the ssc cryogenic system design and operatingmodeslss.fnal.gov/archive/other/ssc/ssc-n-868.pdf ·...
TRANSCRIPT
‘I,Ct
The SSCCryogenic SystemDesignand
OperatingModes
SuperconductingSuper ColliderLaboratory
SSCL-N-868SSCCryo Note 92-12June1994Distribution Category:400
R. ThanS. AbramovichV. Ganni
SSCL-N-868SSC Cryo Note 92-12
The SSCCryogenic SystemDesignand
Operating Modes
R. Than, S. Abramovich,andV. Ganni
SuperconductingSuperCollider Laboratory*2550 BeckleymeadeAve.Dallas, TX 75237 USA
June1994
*Operatedby the UniversitiesResearchAssociation,Inc., for the U.S. Departmentof EnergyunderContractNo. DE-AC35-89ER40486.
1. INTRODUCTION
TheSSCis an applicationof superconductivityon a scalevastly largerthan any before. Anextensivecryogenicsystemis required,capableof providingfor the normaloperationofthe superconductingmagnetswhile handling transientconditionssuchasquenches,beamactivation and ring filling, and beamrampingacceleration.Thecryogenic systemmustalso be able to perform servicessuchas cleanup,cooldown, and warmup to allow formaintenanceandrepairof thesuperconductingcomponentsthroughoutthering.
Themagnetsin thecollider rings and in theHER high energyboosterring will berefrigeratedby single-phasehelium flow controlledat a temperatureof 4 K to maintain themagnetwindingsin a superconductivestate. To minimizetheheatload into the4 K loop,themagnetcryostatsaredesignedto providehigh quality thermal insulationat nominaltemperaturesof 84 K and 20 K, using thermal shields contained in a high vacuumchamberwith multilayer insulatingmaterialsMLI.
The two collider beam tubesare encasedin parallel rings of superconductingmagnets,eachring 87,120m in circumference;the magnetrings are installed one above
the other, 90 cm apart,in a tunnel 25 to 74 m below ground. The HEB single ring,
10,800 m in circumference,is constructedin a separatetunnelparallel to and 14 m above
thecouidertunnel.This immensesystem,if it isto be broughtinto operationwithin a reasonableperiod
of time, requiresparallel plans for tunnel construction and for installation and
commissioningof themagnets. Thus,a highly centralizedcryogenicsystemwould not be
adequate.Instead,therewill be aseriesof units,eachcapableof independentoperationbutinterconnectedfor redundancy.Thenumberof independentlyoperatingunits is determined
in a trade-off betweeneconomiesof scalein the refrigerationplants and the cost oftransportingheatfrom themagnets.Thedesignof theSSCcallsfor ten sectors,eachover8 km in lengthwith a helium refrigerationplant installedat midpoint. Thecryogenicheatload for the HER resultsprimarily from rampinglossesin thesuperconductingmagnets
andis aboutten times greaterthanthesynchrotronradiation,the largestdynamicheatloadin thecollider. Two helium refrigerationplantseachwith a capacitysimilar to a collider
plant arerequiredfor theHER.Figure 1-1 is a schematicview of the SSC and the relative locations of the
refrigerationplants.
3
A location for the air
-j..
i
Fz,
-U
L
‘
location of cryogenics end boxes0 in the tunnel
Figure 1-1. Geometry of the collider and the HER rings and the locationof the heliumzefligeration plants.
highest pointin the collider
N5O
o loeMioti ° the helium refrigeration plantsand the vertical fransfer lines
4
2. THE SYSTEM GEOMETRY
2.1 THE COLLIDER RINGS
The main tunnel of the collider is on a plane with an inclination of 0.2 degrees. It isconfiguredin two arcs,north andsouth,connectedon theeastand westby almost straightsectionsseeFig. 1-I. The highestpoint in the tunnel is in the vicinity of N15, and thelowestpoint is closeto S15.
A helium refrigerationplant locatedon the surfaceservesa sector in the tunnel
extendingapproximately4.3 km to eachside of theplant. The locationsof the heliumrefrigerationplantsfor thecollider are designatedN15, N25, N35, S15,S25,etc.
Cryogensaresuppliedfrom theplantsto thetunnel throughtransferlines in verticalutility shafts near the plants. Additional service shafts are located near the sector
boundaries.A schematiccrosssectionof thecollidertunnel is shown in Figure2.1-2
BetweenN15 and N55 and betweenSl5 and S55 the coflider arcscontain almostcontinuousstringsof superconductingmagnets,for which theyrequirea continuousstreamof coolants. Thecryostatsin theseregionsaredesignedto enablethehandling-including
circulation,distribution,andrecooling-ofthedifferentcryogens.The remainingsectionsof thecolliderring containtheutility regionsbeaminjection,
beamacceleration,beamdump, and tune-upand the interaction regions for the maindetectorsof the SSC. In thesefairly straight segments,superconductingmagnetsareseparatedfrom eachother by warmequipment. To closethe cryogenicloops, specialtransferlines bypassthesewarm regions.
5
480V CONU4JT 30 NIChE U480V CONOIJI FOR MUtt IlPJjj LiGHTING C
"TI
-I
‘a-I
r-3
a.’=C’
C,
a
C
jill/kY CNLE®
069kv CNLt I
¶1 DING Nfl WNWV
°SE’[YER1 ®
ILAftR WIFE! 180V WWl /, rririji_p_. ./ // -‘
® rJJ° C’L f /FOUR OUFJ1CII BYPASS CNWES C
4k III ", l-’"".L-.--- I
0 1SlRUt LiKE SlJ1I’ORI -_..j ITTyfTIIE1j___ ‘, ," ‘.
a" iaw GAS P111W IE-4fr- 1 A! ‘
Li’ ‘j4 / ‘C 2" NITPOG[u GAS tlNF_._...4 dh__+n I
i- ,
/wouEY
V
______ ____
z.g..._._. ‘‘
-‘
___
0 MM D‘-4" DIA FIBER OPIIC CONDIJIS ®
Variationsin terrainand in tunnel inclination causeshaftdepthsandtunnel locationsto vary from site to site. Surfaceand tunnel elevationsand the depthof the shaftsfor thecollider are shown in Table 2.1-1 andin Figure2.1-2.
Table 2.1.1. Surfaceand beamaltitudes,in meters
Location Surfacealtitude
Depth tobeamline
jft depthReamlinealtitude
Beamlineref. altitude
N15 El 233.17 74.06 159.11 75.96
N20 Fl 217.17 53.13 164.04 80.89
N25 E2 197.97 33.87 164.10 80.95
N30 F2 207.26 48.00 159.26 76.11
N35 E3 208.03 57.92 150.11 66.96N40F3 161.54 23.70 137.83 54.68
N45 E4 161.54 37.50 124.04 40.89
N50F4 151.64 41.21 110.43 27.28
N55 ES 140.21 41.45 98.76 15.61S10* lED515 E6 150.88 66.48 84.40 1.25
520 F6 140.21 57.06 83.15 0.00
525 E7 139.45 53.40 86.05 2.90
S30P7 145.54 52.76 92.78 9.63
535 ES 129.54 27.04 102.50 19.35
540 PS 155.45 41.49 113.96 30.81
545 E9 156.21 30.51 125.70 42.55
550 P9 163.83 27.61 136.22 53.07
555 ElO 169.16 24.99 144.17 61.02N1O* lED
* SW in the east cluster and N1O in the west cluster are located between the utilitystraights and the interaction regions.
An arrangementof magnetsin series, starting with the feed connectionat therefrigerationplant andendingwith areturn box at thecryogenicsectorboundary,is termeda "string." A nominal string is 4.3 km long. The stringsare segmentedinto "sections"connectedto eachother by U tubesthat enable the isolation of parts of the systemformaintenance.
For practicalreasons,the lengths ofthe magnetstrings andthe lengthsofthesectionsvary, asshownin Table2.1-2.
7
liii iii F I [Ti I I I I I I I I hhfJJUf I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I i I IEAST CLUSTER
WEST CLUSTER
i32Om 387Dm 432Cm 4626m 4463m 4320m 432Dm 432O SI I2m 3886n 3906m 4823n, 4050m 3960m 486Om 4320m 4320,.. 3472g. 5333m 3886m
IR4IR3IR2IRI9415 NEC 9425 9430 N35 9440 9445 N50 9455 SIC SIS S20 525 S30 S35 S40 545 S50 S55 9410 N15
1R8lR7 1R6IR5NI5ELEVA1ION ‘ ‘i..... 1
10 + 44 $44 itt 444 -23020 130 123 135 49 II ISO 047 ISO 130 19 I 97 8 .220
-21030.q 40e 50 190
ISO
BEKUNE
r N-L A- 80 160
41
::Z . 170
ISOI;J 90 IS *fl
N
. ISO140
a 130 i -r
. 200
.S 120B - 110
140 I -. 100. ‘5° I I I
_____________
90160 I I I 80170 SE IUNEA 11102 I I I 70ISO I I I - 60
9 390 159 164 164 159 ISO ‘38 024 110 99 84 83 86 92 102 114 125 136 044 159 .502. 200 40
- 30210 444441441 fl 4444444444 20220230 ID
0
UNITS IN MEIERS
Z’C11ON REGION
INTERAC11ON REGION
HIGH ENERGY SOthTER
K NI5AIIt/AsST
Table 2.1-2. Length of collider strings and sections,in meters
String Length Length_ofSections
S15 to 520 3906 1080 1080 667 1080S20 to S25 4823 773 1080 1080 990 900S25 to 530 4050 1080 810 1080 1080530 to 535 3960 810 540 1080 450 1080S35 to 540 4860 765 945 630 1080 1080 360S40 to 545 4320 1350 1080 810 1080S45 to 550 4320 1170 720 1080 1350550 to 555 3472 396 1088 1125 1350
5333 450 1116 1087 676 756 1087 298
West Utility 3886 917 990 1350 629
NlStoN2O 4320 1080 1080 667 1080 413N20 to N25 3870 360 1080 1080 990 360N25toN3O 4320 540 1080 810 1080 810N30to N35 4626 1080 540 1080 450 1080 396N35 to N40 4463 953 990 1080 1080 360N4OtoN4S 4320 1350 1080 810 1080N4StoN5O 4320 1170 720 1080 1350N5OtoN55 4320 405 1080 765 1080 990NS5TOS1Ol.R.
5112 1206 1087 676 756 1087 298
510 to 515East Utility
3886 917 990 1350 629
2.2 THE HEB RING
The1-fEB is a bipolarmachinewith onering of superconductingmagnets.It is constructedin a tunnel 10,800m in circumference,locatedin a parallelplaneto thecollider, 14 mabovethecollider tunnel. The generallayout of the HEB ring is shown in Figure 2.2-1.Two helium refrigerationplantslocatedon thesurfaceatH20 andH60 supply thecryogensto theHEB. The boundariesbetweenthetwo cryogenicsectorsareat H80 andH40. Eachof thefour stringsof the HEB is divided into two sections. Altitudes and depthsto thebeamlinearegiven in Table2.2-1. Lengthsof thesectionsareshownin Table2.2-2.
As in the collider, thereare straight regionsalongthe ring wherecryogenflowsb>passwarm equipmentthroughspecialcryogenictransferlines.
9
CI
Injection to the Collider
Straight segments and warm beam eqwpment are located at 1110, 1120, 1140. H50, H60, and 1180
HELIUM
PLANT
From the Medium Energy Booster1*
if’4
Abort lIne
HELIUMREFRIGERATIONPLANT
Figure 2.2-1. The HEB ring.
Table2.2-1. Surfaceandbeamaltitudesfor the HEB, in meters
Location SurfacealtitudeDepth tobeamline
Beamlinealtitude
Beamlineref. altitude
1410 229.3 39.4 189.9 16.31420 247.4 57.7 189.7 16.1H30 248.6 63 185.6 12H40 233.6 55 178.6 5H50 226.2 52.5 173.7 0.11460 226.6 53 173.6 01470 221.6 43.3 178.3 4.71480 215.0 30.2 184.8 11.2
Table 2.2-2: Length of FEB stringsand sections,in meters
String Length Length of SectionsFf80 to 1420 2960 1480 1480Fl2OtoH4O 2440 1220 12201440 to Ff60 2960 1480 1480H60toH80 2440 1220 1220
Thenitrogenis supplieddirectly from delivery trucksto theHER’snitrogendewarslocated
at H20 and H60. From the dewarsthe nitrogen is suppliedto the tunnel for the 80 Kshieldrefrigeration,andto thehelium plantsfor precooling. A more sophisticatedschemewould supply the nitrogen through the collider shield lines and is given in detail
elsewhere,.
11
12
3. THE SYSTEM CONFIGURATION
3.1 THE CRYOSTAT
The cold componentscryostatwith superconductingmagnets,spool pieces, empty
cryostats,etc.of thecollider and theHEB are designedfor six differentstreams,describedasfollows:
Line 1 - Single-phasefeed
For normal operation,a nominal helium flow of 100g/s at 4K, 0.4MPa flows through
themagnetsto maintainthecoils in thesuperconductivestate. This flow entersthestring atoneend andexits attheotherend, while beingrecooledevery 180m in recoolerslocatedin
thespool pieces. Thecrosssectionof this flow is definedby thesumof thedifferentflow
areaswithin the magnet. A small amountof this feed streamis tappedoff at differentlocationsalong the sthng for therefrigerationof the high currentleads,the bypassleads,and thecurrentleadsfor thecorrectormagnets.
Line 2 - Single-phasereturn
This line, which has an insidediameterID of 45.2mm, is mounted in the vacuumenvelopealongsidethemagnetwinding case. It carriesthesingle-phaseflow from the endofthesiring backto therefrigerator. A sizableportion of this return streamis injectedintotherecoolers.Undernominalconditionsandfor a nominalstring length in thecollider, thebalanceof theflow returningat theendof the line is approximately25g/sper string. Theheatload of theHEB stringsis higherthanthat of thecollider andthehigh boil-off ratein
the recoolersmay requiresupply of single-phaseflow from both ends.
Line 3 - 4K helium vapor return
This line, sizedat 86.5mmID for thecollider and 110mmID for the HEB, returnstheboil-off helium from the recoolersto the cold compressor,which dischargesit to therefrigerator.
Line 4 - 20K feed/return
For the 20 K shield loop, 82.5mmID pipe is used.Thedesign flow rate is lOOg/s at 0.3MPa with adesignload of 2500Wper string or a total of 5000Wper loop. Accordingto a given scheme,theflow is suppliedto thetop ring andreturnedto theplant throughthebottom ring. A different schemecalls for a clockwise flow in one ring andcounterclockwisein thesecondring; this mayallow for sharingloadsbetweensectorsandbalancingmassinventory.
13
In the HEB the flow is routed from one refrigeratorthrough the two connectingstringsto the secondrefrigeratorfrom H20 throughH30, H40, and H50 to H60; and fromH60 throughH70, H80, and H10 to H20.
Line S - 80K LN2 shield line
This 57.2mm ID line is used to distribute the liquid nitrogen in the tunnel for the
refrigerationof the 80K shield andto supply liquid nitrogen to the refrigerationplantsfor
precooling. A detaileddescriptionof the nitrogensystemis presentedin "Nitrogen System
for theSSC."
Line 6 - 80K GN2 shield line
A second57.2mmID line is usedto return thevapornitrogenproducedin the nitrogen
recoolersto thehelium refrigeratorfor precoolingpurposes.Thevapor is subsequently
ventedto atmosphereat300 K.
Warm helium return header
A warm returnheader,sizedat 213mmID, is installed in thetunnel to return the warmhelium flow from thecurrentleads. This headeris alsousedto returnwarm helium during
cleaning,cooldown,and maintenanceprocesses.Theinsulatingspacesaroundthecryogeniccomponentsmagnets,spoolpieces,and
transferlinesareevacuatedto 1.3 x 10-2Pa by mechanicalpumpsandto 1.3 x l0- Pa by
cryo pumping. This vacuumis requiredto minimize theheatload on thecold mass. The
insulating spaceis boundedradially by theouter walls of thecryostatand axially by the
vacuumbarrierslocatedin thespool pieces.In the coffider, the insulatingvacuumvolumebetweentwo vacuumbarriershalf-cell is approximately22m3.
Crosssectionsof different cryostatsare shown in Figure 3.1-1 collider dipole,Figure 3.1-2 collider and HER bypasses,and Figure 3.1-3 vertical transfer lineconnectingthe surfacehelium refrigerationplants to therings in the tunnel.
Besidesthe standardcryostatsand bypassesusedin the collider, therearemorecomplicatedcryostats,suchas thosecontainingtwo cold massesFig. 3.1-4 and thosewhich requirecomplexconnectionsto the cryogenic bypasses.Thesewill be discussedelsewhere.
‘McAshan, M.. M. Thinimaleshwar,S. Abramovichand V. Ganni. SSC LaboratoryReportNo.SSCL-592, September1992.
14
UNE I
UNE 3CUE RETURN88.900X 1.2WAIl.
LINE 6CN357.2ID
UNE420K SHIELD
LINE 2SINGLE PHASE RETURN47.6 0123<1.2 WALL
DIMENSIUS IN MM
Figure 3.1-1. Typical collithpoleayostaxcrossseaion.
vessel
‘l’he collider bypasses
The HEB bypasses
Figure 3.1-2. Bypasscryostatcross sections
80 K LN2
GN2
4 K singlephase
return
4KGHe
20
4 K single phasewith cold buses
K single phase return
16
4
Outer wall of the vacuum vessel
4K
return
Figure 3.1-3. Crosssectionof a vertical transfer line from the surfaceto the tunnel
VEEL
CUE 2DK SHIELD
% 82.5 ID
CUE 20K SHIELD82.5 ID
DfMFJJSIOMS IN MM
Figure 3.1-4. Cross stion of cryostatcontaining two veitical bendingdipol
3.2 THE CELL AND THE HALF-CELL
The collider half-cell
The smallestrepetitivegroupof magnetsdipolesand quadrupolesin an acceleratoris thehalf-cell. A regularcollider arc half-cell containsfive dipoles,a quadrupole,and a spoolpiece, and its length is 90m. Figure 3.2-1 showstheconfigurationof a regular arc half-cell and that of an isolation half-cell. The spool piecescontain correctionmagnets,recoolersevery otherspool, cryogenicinstrumentation,a vacuumbarrier, and quenchprotectionbypasses.This designenablesthe systemto contain vacuumproblemsandmagnetquenchingproblemswithin the half-cell.
Half - cell - 90 m
5.85m 4.575 m 15.815m 15.815m 0.5 in 15.815 in 15.815m 15.815mS1’RA CDM CDM CDM CDM COM
QM or iSm 15m C 15m ISm lSniSPXA
..85m 7.125 in 13.2875m 15.815 m 0.5 m 15.815 m 15.815m 15.815in
CQM SPIt!CDM CDM CDM CDM CDM
in lSm 15m iSm lSm
CDM1S - Regulararc dipole 15.8150 m longCDMI3 - Regulararc dipole 13.2875 m longCQM - Regulararc quadrupoleSPXA - Arc spool without recoolerSPRA - Arc spool with recoolerSPRI - Isolationspoolwith recoolerC - Correctionelements
Figure 3.2-1. The collider half-cell
The HER half-cell
In the HER a regulararc half-cell containstwo HEB dipoles,one HER quadrupole,and aspool piece, Thelength of ahalf-cell is 32.5m. Figure 3.2-2showstheconfigurationof aregulararchalf-cell of theHER. A vacuumbarrieris locatedin everyotherspool -65m.Thealternatespool containstherecooler. Therecoolersandvacuumbarriersarelocatedinalternatespoolsbecauseof spacelimitations.
Half - cell with cryo isolation -90 m
19
Half Cell - 32.5 m
2.485m 3.675 inSPRA
13.171m 13,171 m
Q or j BSPXA
slot length
B - Regulararc dipole 13.171 m longQ - Regulararc dipoleSPXA - Arc spool without recoolerwith vacuumbatherSPRA - Arc spool with recoolerwithout vacuumbarrier
Figure 3.2-2. The HER half-cell.
3.3 SECTIONS AND STRINGS
A cryogenicsectionis a seriesof cells with an isolation can at eachend. Thecryogenic
connectionbetweentwo sectionsis madethroughU-tubes.
A cryogenicstring is a seriesof sectionswith a cryogenicfeedcan on oneendandan
end canreturncanat theotherend.
Thelengthof a nominalsectionin thecollider is lO8Om andthenominal length of a
string is 4320m. The actuallengthsvary asshownin Table2.1-2,above.
In the HER there are two standardsections, 1220m long and 1480m longrespectively.Eachstring in theHER containstwo sectionsof the samelength; thus, there
arestrings 244Dm longand stings296Dm long seeFigure2.2-], above.
3.4 THE CRYOGENIC SECTOR
The collider cryogenic sector
Figure 3.4-1 depictsa specific cryogenicsector in the collider. It includesregulararc
stringsNl5 to N2D and the westutility straightwith thebypasstransferline. Thereis aseriesof isolatedcryostatsconnectedto thebypassbut not shown in thediagram. A typicalcryogenicsectorstructureis given in Table 3.4-1.
20
The HEB cryogenic sector
Thereare two cryogenicsectorsin the HEB, each5400mlong, with their refrigerationplants locatedat H20 and H60. TheH20 areacontainsthe injection into thecollider andtheHER beamdump. The H60 areacontainsthe beaminjection from the MEB to the HEBand futurebeamtestequipment Thesedifferencescausesomedifferencesin theheatloadsfor thetwo sectors. Theflow directionuphill in H60 anddownhill in H20, causesomedifferencesin thepressuresin the linesdueto static headeffects.
22
SECTOR Ni
N15 N20
__________________________________________
NI_s*rTTtNrc
STRING i STRING I
IEO 5ICfl SECON 5IC
F
____
it, I/i, IMjj
SIcno ,gcTIo,. liefloli SIC’TION StCtIOII
sppi snu snj F ISPRB Sn’ sni SPRI 05! InS
"rflOt SICflOI tCTIQN SECTION
Ins
SICTIOI.‘acne, SECTTI SECflOTISI oil vi 212 in it,
UTILITY S1RAIGET
STRING 4
*17. 440_ _j_ 1314e - - - In.. 075. In..
- r *y r- nfl-
Figure 3.4-1. Definitions of a cryogenic sector for the collider.
Table 3.4-1. Typical structureof a cryogenic sectorin the collider.
IN EACH RING
H If-cellFive dipoles with interconnectionsQuadrupole with interconnectionsSPXA spool with: conectioncoils, bypassleadswith quenchstopper, beam-linepump-out, quench vent valve,vacuumbarrier, andinstrumentation
90 in long
Cell: Two half-cells including SPRA spoolt 180 in long
Section: Six cells including SPRI spool at each end.** 1080 in long
String: 24 cells; 4 sections including an SPRE spoo1at one endandan SPRFspootatthe other end. SPREandSPRFspoolswith end boxeswith 7 kA lead pair, U-tubes.connection to refrigerator, andinstrumentation
Refrigeration connection box with transferlineAuxiliary end box connecting with adjacent sector
4.320 km lone
Including both rings:Cryogenic sector four strings in pairsRefrigeration plant with compressors, helium management system with gasstonge.
liquid helium storage, liquid helium circulatorandsubcooler. liquid nitrogen circulatorandsubcooler, liquid nitrogen storage
8.640 km long
* These distances may vary and depend on the position of isolation,feed,andend spool.given are "nominal" values.
** Spool definitions are given in Section 4.1.
Numbers
N10
in..
STRING 2
441.
21
4. SPECIFIC CRYOGENIC COMPONENTS
4.1 THE SPOOL PIECES
Genericnamesfor thedifferentspoolsare listed below:
SPXA Standardspool with no recoolerFig. 4.1-1.SPRA Standardspooi with recoolerFig. 4.1-1.
SPRI Isolationspool with a recooleron theright sideFig 4.1-2.
SPRF Feedspooi with recoolerson both sidesFig. 4.1-2.
SPRE End spooi with a recooleron the right half. The righthalf is partof one
sectorand the left half is partof the adjacentsector.
SPXS Standardspoolwith no recoolerextended2.5 m with theaddition of an
emptycryostat.SPRS Standardspool with recoolerand 2.5mextension.
SPRT Spool with recoolerto connectan isolatedmagnetto a bypassFig. 4.1-3.
SPRB Spoolwith recoolerto connecta string of magnetsto a bypassFig. 4.1-4.
SPRC Spool with recoolerto connectan isolatedmagnetstring to a bypass
Fig. 4.1-5SPXR Returnbox Fig. 4.1-3.SPXU Standardspoolwith no recoolerand no vacuumbarrier,used in the utility
straights.
Figure4.1-1 is an isometricview of a standardspoolwith no recooler. In thecolliderthe SPRA is similar to theSPXA, but containsa recoolerconcentricto thecold mass.
Figure 4.1-2 showstheconceptualdesignof theright half of an SPRF. TheSPRE,with a helium recoolerin one half only, is similar to the SPRF but the two halvesareinterconnectedthroughan auxiliary valve box. TheSPRIis thesamelengthastheSPRF,with thetwo halvesconnectedby U-tubes.
4.2 THE EMPTY CRYOSTAT
Theregularempty cryostatEC for the collider and for theFIEB containssix cryogeniclines Sec.3.1, above. Like themagnetsand spool pieces,it containsthebeamtube andrequiresprecisemechanicaldesign. The4K single-phasehelium line Line 1 is designedto carry the cold superconductiveelectric bus. The standardEC is 15.815m for thecollider and 13.171m for theHEB. Thelead and returnendsof the EC havethe sameinterconnectdesignasfor theregularmagnets.Specialemptycryostatsarerequiredin theinteractionregionwheretwo parallelcryostatsaremergedinto one. Thesespecialcryostatswill contain12 cryogeniclines ofthe samediametersastheEC andavacuumvesselsimilarto thecryostatdesigncontainingtwo vertical bendingdipolesFig. 3.1-4.,above.
23
0
I’
CO
tt
COCO
ii01
C,,
IFigure 4.1-1. The cold mass of a standard spool with recoolerSPRA with supports.
24
IOWFI&&Ir.
Ca
To
2-0-I
aa
‘UI 11111!
P71.11
2207.1
27017.1
_-7150.II I_DO KtY
9111A0E ‘0 000 IbIiSl I ‘UI
111 1105
lop rut5
Bottom ring4K line with cold bus In the bypass4K lIne with cold bus in the magnet
BOX WITHVACUUM BARRIERBPSP BPTB
Q...
BYPASS lSm LONG MODULESBPCR.15 /
Figure 4.1-3. Isolated cryostats in the cluster regions
1.B-
a
-e----
0:
SET - 10 LINES
!j1, 1:gj;t;J.L4
a-----1
TO AT BOX IN THE BYPASS
CONNECIIONS
UM LENGTH WITH RECOOLER
1. Top ringB. Bottom ring
.. 4K line with cold bus In the byp.ss4K line with cold bus i the magnet BYPASSEND BOX
DPEBBYPASSlStn LONG MODULES
BPCR.IS m /* 0----
I o
I -
.v
- **tçtç%, d0 -
9-I
__________
1’!MWARM RETUR?4
4,a
‘
j141LIne 6:80K GN shield
SET 12 LINES
BEAM TUBEI 1
c
I r I_---2- -...-
£---_- -..-- -..- -
-- -..-.- - -.-
.&
Wi
._...
-
-
BEAM TUBE
I
.....4.. ....-...
-.-...-..-.-
QUA DRUPOLE/DWOI
BEB1.4 in
SPXBJPRB "24 mMIP
IN LINE CONNECTION BOXWITH JOINTS TO A BYPASS END BOX
IMUM LENGTH WITH RECOOLER
ÜbOL WITh ENDBOX CONNECTIONS
Figure4.1-4. Connections to the cryo-bypass in the clusterregions
I.B.
Top rl.sgBosom ring4K line withoold bus In the bypass4K line with cold bus I. the magnet
"2Am MINIMUM LENGTH WITH RECOOLER
BYPASS iSm LONG MODULESBPCR-15 /
-
Figure 4.1-5. Isolatedcryostatsfor the skew quadrupoles
BOX WITHVACUUM BARRIERBI’SI’
771
RPTR
I
I: - jr
:. :c::::::::s+ -
tt:tr4r.tt;tz;t;z;;; --w-----±:a :E stsi;:
::::::::::::±:::::t:
;t:t:t:T.j$
.ttttvzttt4fttt.
c
WARM RETURN
TUBE SET . 6 LINES
REAM TURF
. I
Ius I
A4.- -.-.--------------.--.. ?--.-.,
.2
...
f.iEIiE:_i IBEAMTUBE‘ -[
‘VSPRC
4.3 THE CRYOGENIC BYPASS TRANSFER LINE
Thecrosssectionsof thebypasstransferlines areshownin Figure3.1-1. For thecollider
the basic moduleof the bypassBPCR is 15.815m long and contains12 cryogenic lines.
For the HEB the basic module is 13.171m long and containssix cryogeniclines. Thefeedlines of the single-phaseflow carryhigh currentbussesfor themagnets.
In the bypassthereare severalcryogenicboxesto enabletheconnectionof isolated
magnetsaswell asboxesfor vacuuminstrumentationandhelium recoolers.Theseare:
BPEB To connectthemagnetstring to thebypass12 connectionsin thecolliderandsix in the HEB
BPTB To connectan isolatedcryostatto thebypass10 connectionsin thecolliderandsevenin theHEB
BPSR A box with a recoolerand/ora vacuumbather
In the HEB the sectorfeed can, the sectorend cans,and the isolation spoolsarelocatedin thebypass.
4.4 THE TRANSFER LINES AND UNDERGROUND DISTRIBUTION Box
The undergroundtunnel distribution box Fig. 4.4-1, Collider and Fig. 4.4-2, HEBdistributes the cryogen streamsfrom the surfacerefrigerator, via the helium coldcompressorbox andthe liquid nitrogensubcoolerbox, to thefour stringsof the collider or
to thetwo strings of theHEB. Transferlines connectthe undergrounddistribution box tothe helium cold compressorbox and liquid nitrogen subcoolerbox. These lines aregroupedinto bundleswhich arepackagedin superinsulatedvacuumvessels.
The shaft transfer line system STL.
The shaft transfer line connnectsthe surfacedistribution box to the tunnel’s coldcompressorbox. It contains:
a. Single-phasefeed helium
b. Single-phasereturn helium
c. Gaseousheliumreturnline helium
d. 20 K feedhelium
e. 20 K returnhelium
f. LN2 line
g. ON2returnline
29
Cryogenic distribution lines
The transferline bundlefrom thecold compressorbox to the undergrounddistribution boxcontains:
a. Single-phasefeed helium
b. Single-phasereturnhelium
c. Gaseoushelium returnline helium
d. 20 K feed helium
e. 20 K returnhelium
f. LN2 line
g. ON2 returnline
Thetransferline bundlefrom theundergrounddistribution box to the LN2 subcoolerbox contains:
a. LN2 lines6
b. ON2 return line 1
The transferline bundlesfrom theundergrounddistributionbox to the feedspools
four bundlesin thecollider, two in the HEB eachcontain six lines:
a. Single-phasefeed,Line I helium.
b. Single-phasereturn,Line 2 helium.
c. Gaseousheliumreturn,Line 3 helium.
d. 20 K feed/return,Line 4 helium.
e. LN2, Line 5.
f. ON2return,Line 6.
The Underground Distribution Box UDB
Theundergrounddistribution box splits themain supplystreamsto thefour strings. Theflow through eachline is regulatedby a control valve and/oran ON/OFF isolationvalvelocatedin this distribution box, asfollows:
a. Single-phasefeedcontrolvalve,Line 1.
b. Single-phasereturnON/OFFvalve,Line 2.
c. Gaseoushelium returnline ON/OFFvalve,Line 3.
d. 20 K feed/returncontrolvalve for supply, ON/OFFfor return,Line 4.
e. LN2 feed/returnline ON/OFFvalve, Line 5.
f. ON2 line ON/OFFvalve,Line 6.
30
E
L
__
JHAFr
p SHAVF TRANSFER LINE
COLD COMPRESSOR BOX
SO K SHIELD
/jL
____
joR
_____
- - - -- - - - -- LIOLThD w*:t.:Y:xxc:x::.
11ft0
______ ____________________
- - - - -: -. U *1941NDERGROIWJD -- -.
- - - - - <- - -: - LIQUID
IISTRIBUTION - - -- -- 0
‘OX u’*-’ *i-"" -
TOP RING 11ff HALFRRF TOP G RIGHA1flPRF
-L1NE I TEL I 1 I/k
4-LINE2T/L I I I ‘‘‘T/R
#LINE3 TéL I I I tttiriTpR
INE4T/L } LDIEIT/R
LJNEST/L N ** LIP/lITER
LINE 6 TEL .._it.. SLOPE INE6 T/E
OTTOM RING RIGHT HALF SPIFIOJTOM gINO IS? HAISS
WARM Ni VAPOR
_____________ _________JNKI./R
TOTIIESURFACELW I TOPRINO
l/t I I - SOTTOMRING-
____
SI/L - - iaos4, . L - LEP7STRINGLINE a. 4m J.NEn’R I - 1110111 STRING
LIQUID NTTROGV DUMP
Figure 4.4-1. Collider cryogenic distribution lines, underground distribution box and LN2 coldbox
HU
13
"or. ,-4 ftrotmt*o. ,0 -T*. UTIUTYOTRMOIT
Figure4.4-2. HEB cryogenic distribution lines, underground distribution box, and LN2 coidhox
4.5 THE AuxILIARY END Box
This box servesasthe interfacebetweentwo sectorsand is locatedat the end of a suing at
theeven-numberedsites. It containsisolation valvesthat allow cryogensto flow across
sectorboundaries. It also containsa nitrogensubcoolerthat is partof thenitrogenshieldcooling system. Thearrangementof the end spoolsand auxiliary end box can be seenin
Figures4.5-1 and 4.5-2.
TOP RING LEFT HALF SPRE
LINE I TELLINE I TELLINE 3 TEL
NE 4 TELLINE 6 TEL
IBOTFOM RING LEFF HALF SNI
flUNEIB/LLINE 2 WI
LINES WL
j
I.TNWAW1
I ItIr 0 WI
a.4j II.
TOP RING RIGHT HALF SPRE
LiNE 1 TER
LINE 2 TERLINE 3 ‘FIR
________UNE4TER ______
LINE S T/R4*4
BOTTOM RING RIGHT HALF SPRE
LINEI BERf’EThEl 8/4
LINE 3 BRLINE 4 HER
LINE S S/R
‘ 4ttruNEA-S
Figure 4.5-1. Collider SPRE and auxiliary end box
T . K
T
*0
WARM VAPOR TOThE SURFACE
UQU
LIQUID NITROGENDUMP
P
FI
33
VAPOR TO 4SURFACE
LIQUID NITROGEN DUMP
Ht4
H 1
1Ett:G sUBCOOLEljH4-’
-U
_________
I .I’r 3
I IN? S
_________
Ifl
Bypass Transfer line Bypass Transfer line
Figure 4.5-2. HER bypass end box SPRE and auxiliary end box.
4.6 THE COLD COMPRESSOR Box CCB
Thehelium cold compressorbox servesasthe interfacepointbetweenthe shafttransferlinesystemand theremainderof the tunnel equipment. It alsocontainsthecold compressorthat maintainsthe boiling temperaturein the recoolersof themagnetstrings at 3.95 K-4.00 K. The single-phasehelium main feed flow from the surface is cooled in a heatexchangerby the returnvapor and the remainingreturnliquid from themagnetstings. The
34
cold compressoroperateswith an inlet temperatureof 4.3K and at a suctionpressureof
0.75bar, and dischargesat 1.45bar. Therewill be additional connectionsto install a
secondcold compressor,operatingin serieswith thefirst, for conditioning of the magnet
stringsby a temporarytemperaturereduction. The appropriatebypassand isolation valves
aredesignedinto this box to performthevariousutility loops andstandardoperatingloops
of the cryogenic system. Figure 4.6.1 shows a conceptualschematicof this box. An
alternatedesign configuration involves the compressionof the saturatedreturn vapor
without superheating.
Figure 4.6-1. Cold compressor box.
SHAFT1RANSFERLINE
44
35
4.7 NITROGEN C0LDB0x NCB AND LN2 RECOOLERS
The nitrogen coldbox is part of the 80K nitrogen shield cooling systemfor the magnetstrings. Themain componentsin this box are:
a. A subcoolervessel and the appropriateheatexchangersto subcool theflows.
b. A circulation/boosterpump for boosting the LN2 pressurefor localcirculation and/orto supply the flow into thenext sector.
c. A boosterpump to supply liquid to the surface
d. Appropriatevalving to operatethenitrogenshieldcooling systemin various
configurations. SeeFigure4.7.1.
LN2 recoolersarelocatedat given intervalsin the tunnel to recoolthe liquid nitrogen
streamthroughthe 84K shield. Thevapor generatedin therecoolersis returnedthroughtheGN2 line to theheliumrefrigeratorand ventedinto theatmosphereat 300K.
4.8 NITROGEN DUMP TANKS NDT
Two uninsulated3000gallon tanksarelocatedin the tunnelfeed areaodd-numberedsitesNl5, N25, N..., 515, S25, S... and in the sectorboundaryarea even-numberedsites
N20, N30, N..., S20, 530, S.... Thesetanksareusedasemergencydump tanks. In the
eventof an accidentto the magnetvesselwhich might causeLN2 to drain into the tunnel
space,thenitrogenshield systemis depressurizedby sendingliquid to thesedump tanks.
Vapor generatedin thesetanks is ventedto the surfacethrougha vent stack. The LN2
dump tankscanbe locatedasshownin Figure 4.5-1,above.
36
S. HEAT LOAD BUDGET
Heattransferinto thecomponentsatliquid helium temperatureis minimized by two thermalshieldsmaintainedat 80K and 20K and by an insulating spacemaintainedat highvacuum. Heat input to the 4K componentsis characterizedinto two loads: dynamicandstatic. Themajorportion of dynamicload is causedby thesynchrotronradiationfrom thebeam. Static load resultsfrom the heatconductionand thermalradiation loadsfrom thewarmerpartsin thecryostat. This heatfrom the4K componentsis removedby circulatingsingle-phase4K helium through thesecomponentsand by recooling this single-phasestreamin recoolersalongthe string.
The heatload from the4K componentsis reflectedasa 4K refrigerationload on thehelium plant. Somecomponentsthat protrudefrom theoutsideinto the4K parts of thecryostat,suchaselectricalleads,are cooledby small streamsof 4K helium; this helium is
returnedwarm to theplant andtranslatesinto a liquefaction loadon theheliumplant.The temperatureof the 20K shield is maintainedby circulating 3 bar helium gas
throughtheshieldat a supply temperatureof 14K. Heat into the 80K shield is removedby an independentnitrogencooling system. Theheatloadsof thevariousequipmentare
budgetedto one of the threeloadson the helium refrigerationsystem-thatis, the 4Krefrigerationload, the liquefaction load, or the 20K shield load. The 80K loads arebudgetedto thenitrogencooling system.
5.1 HEAT BUDGET FOR THE COLLIDER
A typical collider sectorconfigurationis given in Table3.4-1, above.
Collider main componentsheat budget
The heatbudgetfor themain magnetsis given in Table 5.1-1. The heatbudgetfor thevariousspooisis given in Tables5.1-2 through5.1-5.
37
Table 5.1-1. Heat budget for the main magnetsStatic heat loads
WattsDynamic heat loads
WattsMagnet
typeInfrared
andsupport
Intercon TotalStatic
Synchro-tron
Radiation
Splices BeamMicro-wave
BeamGas
TotalDynamic
TotalMagnet
CDM-15 m
Dipole
4 K20 K80 K
0.214.735
0.150.322.1
0.365.037
2.17 0.14 0.2 0.14 2.64 3.05.0
37.0CDM-13 mShortdipole
4 K20 K80 K
0.204.4232
0.150.322.1
0.354.7434.1
1.81 0.14 0.19 0.11 2.25 2.64.7434.1
CQM-Qui
4 K20 K80 K
0.081.813
0.150.322.1
0.232.115
0.74 0.22 0.17 0.05 1.18 1.412.115.0
Table 5.1-2. SPXA-type spoo1 heat budget including interconnect
Heat BudgetLiquidG/S
4K 20K 80K
Total static heat loadDynamic heat loads:
Synchrotron radiationSplicesBeam microwave loadBeam-gas load
0.072 2.58
0.650.080.170.04
15.1 54.5
Total dynamic heat load 095*
Total SPXA-type spool 0.072 353* 15.1 54.5
* The sychrotron radiation heat load is generated in the dipole magnets and some is deposited in thespool pieces. The sector heat loads listed in section account for the synchrotron heat load as beinggenerated and deposited only in the dipole magnets.
38
Table 5.1-3. SPRA-type spool heat budget including interconnect
Heat Budget UquidGIS
4 KW
20 KW
80 KW
Static heat loads:Total static SPXA-typespool 0.072 2.58 15.1 54.5Single-phaserelief line 0.03 0.3 1.4Recoolerfeedvalve 0.03 0.3 1.4Recoolerlevel gauge 0.03 0.3 1.4
Total staticDynamic heat loads:SPXA-typedynamic
Total SPRA.type spool 0.072
2.68
0.95*3.63*
15.9
15.9
58.7
58.7
* The sycspool piecegenerated
hrotron radiation heat load is generated in the dipole magnets and some is deposited in thes. The sector heat loads listed in section account for the synchrotron heat load as being
and deposited only in the dipole magnets.
Table 5.1-4. SPRI-type spool heat budget including interconnect
Heat Budget
Total static heat loadDynamic heatloads:Total static SPRA-type dynamic spoolSynchrotron radiation
LiquidG/S0.072
4KW
5.59
0.95*0.28*
20KW
28.1
80KVV
194
Four SplicesBeam microwave loadBeam-gas load
Total dynamic heat loadTotal SPRA-type spool 0.072
0.080.320.021.66
7.25* 28.1 194
* The sycspool piecegenerated
hrotron radiation heat load is generated in the dipole magnets and some is deposited in thes. The sector heat loads listed in section account for the synchrotron heat load as being
and deposited only in the dipole magnets.
Table 5.1-S. SPRF/SPRE-type spool heat budget including interconnect
Heat budgetLiquidgjs
4KW
20KW
80KW
Static heat loads:Total static SPRI-type spool 0.07 5.59 28.1 194Lessbusconnection -0.1 -4.00 -152pairs6.6kAcurrentleads 1.58 31.7 4.00 20
Total static 1.66 37.2 28.1 199Total dynamic SPR.I-type spool .7 0 0Total SPRF/SPRE-type spool 1.66 38.8* 28.1 199
* The sychrotron radiation heat load is generated in the dipole magnets and some is deposited in thespool pieces. The sector heat loads listed in section account for the synchrotron heat load as beinggenerated and deposited only in the dipole magnets.
39
Collider string heat budget
The heatbudgetfor a typical string is given in Table 5.1-6. There is a differencein theexpectedheatloadsfor thedifferent strings dueto small variationsin thedesignof the arc
strings. Theheatbudgetfor 20 collider strings in onering is given in Table5.1-7. For the4 K loadsthreevaluesare tabulated: the static load theheatleakwith no particle beamin
the system,thedynamicload the addditionalload dueto theexistenceof thebeam,and
the total loadthe sumof the two.
Collider sector heat budget
The sectorheatload is calculated by summationof the loadsof all stringsconnected to the
same feedplus the additional global loads of the sector. Table 5.1-8 showsthecalculated
heatload for each helium refrigeration plant. Figure5.1-1 givesthegraphical comparison
of the heat loadsfor the different sectors.
40
Table 5.1-6. String and sector heat budget
ItemLiquefaction
g/s4 KW
20 KW
80 KW
String heat load static:Dipoles 240Quadrupoles 48SPXA-typespools 24SPRA-type spools 20C0.548SPRI-type spools 2SPRF.Type spools 2
1.71.4
0.23.3
8711625471174
1213100361318
155656
888072013101170100390400
Total Static 6.6 306 2121 12970Siring heat load dynamic:Dipoles 240Quadrupoles 48SPXA-type spools 24SPRA-type spools 20SPR1-type spools 2SPRF-type spools 2
633217622
Total Dynamic 671Stringtotalheatload 6.6 977 2121 12970
Sector heat loadsSector static heat loadsSector dynamic heat loadSector allowancesHelium storageRefrigeration connection boxAuxiliary end boxTransferlinePump boxPump workPurifier operationQuench and cooldown icoveiyPerformance and controlUnallocated
26.5
0.8
3.51.53.7
12272682
81010
140550
500273
51880
150200500400
2500
50004370
Sector total heat load 36.0 5400 10000 65000Redundancy adjustment factor 1.25 1.25 1.5Refrigeration plant cajaity required 45.0 6750 15000 65000
41
Table 5.1-7. The string heat loads
.
Suing HeatLoadsLiquif.
g/s4K
WattsStatic
4KWatts
Dynamic
4KWattsTotal
20KWatts
80KWatts
N10-N15 4.39 238 325 562 1626 10223N15-N20 6.77 314 661 975 2145 13072N20-N25 6.26 285 596 881 1908 11742
N25-N30 6.62 309 663 972 2120 13005
N30-N35 6.91 332 724 1056 2314 14238N35.N40 6.77 317 683 1000 2190 13403
N40-N45 6.62 306 663 968 2107 12866N45-N50 6.62 306 663 969 2108 12870N50-N55 6.77 314 664 978 2151 13118
N55-Sl0 14.04 547 566 1113 2960 17596
510-515 4.39 238 325 562 1626 10223
S15-S20 6.41 288 599 886 1932 11755
520-525 7.06 336 733 1069 2353 14366S25-S30 6.41 291 621 912 1977 12087
530-535 6.34 289 607 897 1948 11970S35-S40 7.13 343 745 1088 2401 14705S40-S45 6.62 306 663 968 2107 12866S45-S50 6.62 306 663 969 2108 12870S50-S55 6.48 292 608 899 1966 11944555-510 14.04 547 566 1113 2960 17596H80-H20 9.78 493 1848 2341 2961 170931420-1440 6.95 345 1812 2157 2211 12305Nominal Siring 6.62 307 671 977 2121 12968
Table 5.1-8. The sector heat loads
SectorUquifaction
gj4 K
watts20 KWatts
Ni N10-N15-N20 28.12 4333 854kN2 N20-N25-N30 31.58 4966 9057N3 N30-N35-N40 33.16 5372 10008N4 N40-N45-N50 32.30 5134 9431N5 N50-N55-S10 47.42 5441 11223SlS10-S15-S20 27A0 4157 8114S2 S20-S25-S30 32.73 5223 9660S3 S30-535-S40 32.73 5229 969754 S40-S45-S50 32.30 5134 9431S5 550-555-Nb 46.84 5285 108511120 H80-H20-H40 25.00 6200 7000Sector Design Loads 36.00 5400 10000Refrigerator Capacity 45.00 6750 15000
42
20K HEAT LOAI WATrSI- -8 Ia
C0 0 0 0 0 0
0 0 0 0 0 0 0
T1 TTiT i----
: I
1]
I,CIIC.4C
2tim
.4maC..
U.
U.
‘I,
U.I.U,
U,‘IU’
U’
U,U,U,
4K I.OAIS WAITS
- ‘a U 4- U. 0.
.n.J.::j:j...:: l:
_________
IrI’
4.
S
::HF i.:i ti
±flLILJLJ1
I: -:1.:.: L .1.
I I . I .. .1.
U,
C-4C
2‘a
2LaUI
24-Ui
.4U.U.
I,U.
It
C’,LIU’
U,4-U.
U.U.
l.aC
I.IQt’IFAClION g/s1- - m Ia LI LI 4. 4. UI
C U 0 0. 0 tj. C ft 0 U 0
U,
aU
‘TI
UI
-I
6pC,
51
C
a6,
2U.
.4It
2UUI
24.Ui
2UiU,
UIUI
‘4CaU’
C’,I,,U’
V.
a
I..0
ma0
5.2 THE HEAT BUDGET FOR THE HEB
HEB main components heat budget
Theheat budget for the main magnets in the HEB is given in Table 5.2-1. The heatbudgetfor the various types of spools and cryogenic boxes is given in Tables 5.2-2 thru 5.2-9.
HEB string heat budget
The heat budget for the four stings of the HEB is given in Table 5.1-7, above.
HEB sector heat budget
The heat budget for the two cryogenic sectors in the HEB is given in Table 5.1-8, above.
Table 5.2.1. Heat budget for the main magnets
Magnet TypeTotal Staticj
Watts
Total DynamicHeat Loads
Watts
Total MagnetHeat Loads
Wafts
HDM4K20K80K
0.465.6141.18
11.46-
-
11.925.61
41.18
HQM4K20K80K
0301.9013.53
1.81-
-
2.111.90
13.53
HQM I4K20K80K
0.301.7712A7
1.17-
-
1.461.77
12.47
HQM24K20K80K
0301.8212.88
1.42-
-
1.711.82
12.88
HQM34K20K80K
0.302.0214.53
2.40-
-
2.702.0214.53
HQM44K20K80K
0.302.2216.19
3.39-
-
3.702.22b6.b9
44
Table 5.2-2. HER SPXA-type spool heat budget
H eat BudgetUquefaction 4 K 20 K 80 K
Infrared,support&otherloads 0.072 2.22 13.81 49.17Beam position monitor heat load 0.20 0.60 1.00Interconnect 0.21 0.44 3.50
Total static hea t loads 0.072 2.63 14.85 53.67
Dynamic heat loads 0.29Total dynamic heat load 0.29
Total spool SF XA loads 0.072 2.92 14.85 53.67
Table 5.2-3. HER SPRA-type spool heat budget
Heat BudgetUquefaction
Ws4KVi’
20KW
80KW
Total static heat loads 0.072 2.73 15.71 57.87Total dynamic heat loads 0.29
Total spool SPRA loads 0.072 3.01 15.71 57.87
Table 5.24. Straight section and isolation spool heat budget
Heat BudgetUquefactionw 4K
W20KVt
80KV1
Total static heat loads 0.012 0.67 7.97 23.14Total dynamic heat loads 0.26
Total spool SPXl loads 0.012 0.93 7.97 23.14
Table 5.2-5. Spool SPRI heat budget including interconnect
Heat BudgetUquefäction 4K
W20K 80K
W
Total static heat loads 0.012 0.77 8.83 27.34
Total dynamic heat loads 0.26
Total spool SPRI loads 0.012 1.03 8.83 27.34
Table 5.2-6. Spool SPRI heat budget including interconnect
Heat BudgetLiquefliction
g/s4 KW
20 KW
80 KVi’
Total static heat loads 0.072 5.64 27.89 19236
Total dynamic heat loads 0.37
Total spool SPRI loads 0.072 6.00 27.89 192.76
45
Table 5.2-7. Bypass spool SPRI/SPRF heat budget including interconnect
Heat BudgetLiquefaction
g/s4 KW
20 KVi’
80 KVi’
Total static heat loads 1.644 36.66 22.95 202.33
Totaldynamicheatloads 0.16
Total spool SPRI loads 1.644 36.82 22.95 202.33
Table 5.2-8. End box heat budget End Box = BPEB + CBEB + Tubeset
Heat Budget Liquefactiong/s
4 KW
20 KW
80 KW
Totalstaticheatloads 3.15 10.14 116.89
Total dynamic heat loads 0.08 0.00
Total spool BPEB loads 3.23 10.14 116.89
Table 52-9. T-box heat budget T-Box = BPTh + CBTB + Tubeset
Heat Budget Liquefactiong/s
4 K71
20 KW
80 KVi’
Total static heat loads 3.11 9.85 115.49
Total dynamic heat loads 0.08 0.00
TotalspoolBPTBloads 3.19 9.85 115.49
46
6. FLUIDS INVENTORY AND HEAT CAPACITY
6.1 FLUIDS INVENTORY
Thefluids inventory for a typical collider sector under normal operating conditions is given
in Table 6.1-1. The inventory of the HEB is given in Table 6.1-2.
6.2 SECTOR HEAT CAPACITY
The magnet mass heat capacity and the sector heat capacity for different ranges oftemperatures are shown in Figure 6.2-1 and Figure 6.2-2. At 80K the heat capacity isapproximately 5% of the heat capacity at 300 K.
47
COLLIDER SECTOR FLUIDS INVENTORYFluid units or meters ID. P T Density Volume Mass Volume Mass Mass -Type pet sthng mm MPa K liters kg /jng kg/string jçççto
nominal values P.T nominal P,T nominalper unit or p er meter
LINE I He 0.4 4.05 1,40E-OlII 15.815 m 236 na. 80 11.2 18.880 2.643 10.573DS 13.285m 4 66 9.24 264 37 148CQM 5.85 m 48 n.a 29 4.06 1.392 195 780
4.892Interconnect/unit 88.3 cm 240+48+38 n.a. 26 3.64 8.736 1,2235poo1 pieces 4.585 m 48 na. 85 11.9 4.080 571 2.285Recooler tube side 24 na. 3 0.42 72 10 40
LINE I Total: 18,717LINE 2 He 4320 45.2 0.3 4.3 1.33E-01 1.60 0.21 6.928 921 3,686LINE 3 He 4320 86.5 0.08 4.3 I.24E-02 5.87 0.07 25.374 315 1,259
Recooler shell 24 na. 0.08 4.3 1.40E-01 27.00 3.78 648 91 363LINE 4 He 4320 82.6 0.3 20 6.OOE-03 5.36 0.03 23.137 139 555LINE S 142 4320 57.2 0.5 84 7.80E-0I 2.57 2.00 11,095 8654 34618LINE 6 N2 4320 57.2 0.13 84 5.50E-03 2.57 0.01 11.095 61 244
WARM GAS RETURN He 4320 203 0.11 300 1.76E.04 32.35 0.01 139.748 25 49
Cohider Sector Total Helium Inventory kg 24,629
Colhider Sector Total Nitrogen Inventory kg: 34,862
STORAGE CAPACITY P T Volume MassMPa K jç4_ litersnominal values
Two Helium Dewars: 0.119 4.4 1 .21E-0l 230,000 27,88710 Gas Tanks: 0.16 300 2.55E-03 1,150,000 2,931
One N2 Dewar: 0.3 87.9 7.57E+02 75,000 56,768
Total liquid Nitrogen consumption by the SECTOR is 272 g/stunnet +128 g/s surface =400 g/s or 1.440 kg/h or 34.560 kg/day or 12.6E+6 kg/year
I I IHELIUMPLANTAND VERTICALTRANSFERLINESNOTJNCLULED
Table 6.1-1. Collider sector fluids inventory
.
H E B FLUIDS INVENTORYFluid units or meters h.D. P T Density Volume Ms Volume Mass - MassType p sector mm MPa K kg/l liters kg kg/HER
short/long nominal values Pj nominal P,T nominalper unit or per meter short/long short/long
LINE 1 He 0.4 4.05 I .40E.0 IB 64/64 na. l2.29 rn 66/unit 9.24/unit 4224/4224 591/591 4,728HQM OF or QD 33/35 n.a 1.6 m1 8.62/unit I .2/unit 284/301 39.7/42 327HQMI Ql,Q3,Q4,Q5 0/4 n.a. 0.902 rn 4.8/unit 0.67/unit 0/19.2 0/2.7 IIHQM2 Q2 0/I n.a. 1.173 m 6.329/unit 0.88/unit 0/6.3 0/.88 4
HQM3 QSI 1/I n.a. 2.258 m 12.15/unit 17.0/unit 12.2/12.2 1.7/1.7 14HQM4 QS2,QS3 2/2 n.a 3.347 m 18.0/unit 2.5/unit 36/36 5/5 40buterconnect/U 100/107 n.a. 88.3 cm 26.0/unit 3.64/unit 2600/2782 364/389 3.012Spool pieces 33/35 n.a. 69.25/unit 9.7/unit 2285/2424 320/339 2,636Bypses 1745m similartoemç*yciyostals 4.1/rn 0.574/rn 7l54total IOOltotal 1,001Empty ctyostats 717rn 2x5.7 ID 20%occupied by COLD BUS 4.1/rn 0.574/rn 2939total 411total 411Recoolertubes 17/27 n.a. 3.0/unit 0.42/unit 51/81 7.1/11.3 74
LINE 2 He 1220/1480rn 45.2 0.3 4.3 I.33E.01 1.605/rn 0.2131/rn l958/2375 260/315 2,300LINE 3 He 1220/l480rn 110 0.08 4.3 l.24E-02 93/rn 0.1178/rn 11590/14060 143.7/174.3 1,272
Recooler Wiell 17/27 n.a, l.40E.Ol 27.0/unit 3.78/unit 459/729 64.2/102 665LINE 4 He 1220/1480m 82.6 0.4 20 6.OOE-03 5.359/rn 0.032/rn 6538/7931 39.2/47.5 347LINE 5 142 1220/1480m 57.2 0.5 84 7.80E.0I 2.57/rn 2/rn 3135/3803 24452966 21,644LINE 6 142 1220/1480m 57.2 0c13 84 5.50E-03 2.57fln 0.014/rn 3135/3803 17.24/20.9 153
WARMGASRETURN He 10800rn 8=203 0.11 300 I.76E.04 349000 67.76
HER Total Helium 1nvetorvfkgj 16,908
Total Nitrogen consurnptknby the HER is 450 g/s or 1620 kg/h or 38,880kg/da
Iy or l4.2E+6 kg/year
I IHELIUM PUNT AND VERTICAL TRANSFERLINES NOTINCLUDED
STORAGECAPACITY
Four Helium Dewars:20 las Tanks:
Two Nitrogen Dewars:
P
:.r
nominal’0.119
0.16
0.3
T
K‘aloes
4.4300
87.9
Density
kg/I
l.21E-0I
2.55E-03
7.57E+02
Volume
liters
460,0002,500,000
150,000
HER To al Nitrogen Inventory kg: 21,797
Mass
kg
55,7745,862
113,536
Table 6.1-2. HEB fluids inventory
HEAT CAPACITY MAGNET MASS J/KG
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300
TEMPERATURE K
TEMPERATURE K
Figure 6.2-1. Magnet heatcapacity
80
100000
80000
60000
/ 40000K
c 20000
0
4000
3500C
3000
2500
2000
1500/ 1000K
500
0
0 10 20 30 40 50 60 70
TEMPERATURE K
35
C 30
25
20J/
15
K 10
G5
00 2 4 6 8 10 12 14 16 18 20
50
SECTOR HEAT CAPACITY
C 1.008+12
8.006+11J
0
U 4.006+11
e 2.006+11
$ 0.006+00
4.506+10C 4.008+10
3.508+10J 3.006+10o 2.506+10u 2.008+10I 1.506+10e 1.008+10s 5.006+09
0.008+00
4.006+08
C 3.508+08
3.006+08
230E-+-080
2.006+08U
I 1.506+081.006+08
5.006+07
0.006+00
6 .008+ 11
TEMPERATURE K
UUt
SUU
.* -
.s
*I!
0i I
10 20 30 40 50
TEMPERATURE K
60 70
TEMPERATURE K
Figure 6.2-2. SectorHeat Capacity
0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300
0 2 4 6 8 10 12 14 16 18 20
51
52
7. REFRIGERATION SCHEMES AND OPERATING CONDITIONSOF THE SECTOR STATION CRYOGENIC SYSTEM SCS
7.1 SYSTEM CONFIGURATION DESJGN
The SCSis divided into the sector refrigerator surface systemSRS, the sector refrigeratortunnel systemSRT, and the sectorrefrigerator control systemSRC. The SRS includesall the equipmenton thesurface-thatis, therefrigerationunit, storagefacilities, and allauxiliariesassociatedwith therefrigerationunit. The SRT includesthe cold compressorbox, the nitrogencoldbox, the undergrounddistribution box, thecryogenicdistributionsystem,the shafttransferline system,thenitrogendump tanks,and the auxiliary end box.TheSRCis thecontrolsystemfor theSCSandfor all of its components.
The sectorrefrigeratorsurfacesystemSRS should be able to operateeffectivelyundera variety of operatingconditions. Theprimary functionof this systemis to providerefrigerationto the magnet strings. Secondaryoperating modes include cleanup,cooldown,warmup,andmaintenanceof themagnetstrings. In orderto meetthe operatingrequirementsfor eachmode, a minimum set of componentsis neededto enablethereconfigurationof the systemby including or excludingspecific subsystemsto adjustthecapacityandthroughputof eachsubsystem.The designmustthereforealso provide theappropriateoverall control philosophy of the system,in particular that of the liquidmanagementscheme.Thelatterservesasthe interfacebetweenthesurfacesystemandthetunnel cryogenicssystem,andshould be capableof handlingthevariousoperatingmodes.
Figure 7.1-1 is a block diagram of the major componentsin the sectorstationcryogenic system. Table 7.1-1 lists the cryogenic systemstatepoints,with locationnumberscorrespondingto thenumberson theblock diagram.
53
ThHE GASSTORAGE
COMPRESSOR
I-fl SYSTEM
I
+ 4+4
I
HEsYSTEM
LIQUID HELIUM
STORAGE
PUMPBOX
GROUND
TUNNEL
[ SURFACEDIS1RIBUTION BOX
v: 4COLI COM’RESSORBOX I
1GROUM
IUNWL
SUBCOLERBOX
IUNIIJERGROU’4D DISTRIBU11ONBOX I
J- ‘I SiRING
-I- sri
I ISWING I
©SiRING
___
I I I____I SIRING I
Figure 7.1-1. Sectorstationciyogñc systemblock diagram
Table 7.1-1. Sectorstation cryogenicsystemstatepoints
Loc Description TemperalureK
PressureBar
I Single-phase helium feed 4.0 4.02 Sinple-flrnseheliumreturn 4.0 3.53 GaSeOUS helium return 3.95 0.774 20K shield feed 14-18 3.0
5 20K shield return 28 max 2.06 Gaseousnitrogenreturn 85 1.57 Lkpiid nitrogen flow 80-85 3.0-10.08 LHe supply from refrigentor 4.45 4.0
9 Coldcompressorreturntosurface 6.1 1.4
10 Sin$e-flrnse helium return to dewar 4.3 3.511 Warmheliumgasretum 305 1.1
12 Nitrogen gas 85 1.3
13 High Jxessurehelium 308 20 nominal14 Medium pressurehelium 303 3 nominal15 Low prsurehelium 303 1.0516 20 K returnpressurehelium 303 1.5 nominal
Figure 7.1-2 showsthe configurationchosenfor the SRS. Theheliumrefrigeratorcoldboxprocessshownin Figure 7.1-2 is somewhatsimilar to theprocessin an existingsystemgivenasan exampleonly, theAcceleratorSystemStringTestASST coldbox.
The SRS consistsof the following major systems: the compressorsystemCMS,Fig. 7.1-3 and the refrigerationsystemRFS, Fig. 7.1-4. A brief description of theequipmentfor eachsystemfollows.
Compressor System
1 Compressorgroup: Two-stagecompressionof helium gas for therefrigerator. Theavailablepowerfor operationat designload is 4.5 MW.
2 Oil removal system: Oil removal systemto removefine oil from thecompressordischargehelium flow.
3 Gasmanagementsystem: A set of controlvalvesthat managestheoverallinventory in and out of thesystemat thewarm end of therefrigerator,andallows the refrigeratorto follow loadchanges.
4 Gasstorage:Warm gasstoragecapacityof 1,150,000liters up to 19 bar.
5 Auxiliary equipment: Bearinggascompressorskid, oil managementsystemfor compressorsystem,utility stations,instrumentair system.
6 Piping network: Warmpiping betweengasstorage,compressorsystemandcoldbox.
55
r
AI
3
* e__
E
- dO_j2
_
:
____
--Ie444 ‘%rI
__
____ ____
I-.. I
I ..s.J
____
,, ‘C
______ _______
* I
____ ____
-‘
______
_____
LIIIII. E
*ri
__
frLLJ
___
E
____-
c::1 I
___
H kh’
___ __ _____
-
c, b1c____..II I
I I..*-‘s
Figure 7.1-2. Sectorrefrigentorsurface system flow diagram
______________________________
VAC
HELIUM
__________
GAS GAS MANAGEMENr
________
STORAGE UTILITY
- STATIONS.T1
OIL
MGT.
______________
SKID
n
BEARING
GAS
I COMPRESSOROIL I COMPRESSORSKIDS
__________
REMOVAL -I COMPRESSORGROUP AIRI
_______ ____ ________
TANK
r -
- j
I REFRIGERA11ONSYSTEM I LEADI COOLING
"1
.4-a.1.
I
Refrigeration System RFS
1 Coldboxsystem: Thecoldbox systemis configuredin a seriesarrangementasfollows: The first coldbox300 Km 80 K contains dual full-size heatexchangercores,thenitrogenboiler, and 80 K adsorberbeds. Thesecondcoldbox80 K to 4 K containsthe expanders,the low temperatureheatexchangers,20 K beds,and buffer volume.
2 Liquid managementsystem: A specialsurfacedistribution box servesas theprecooler,interface,anddistribution managerbetweenthe coldboxes,theLHe storagesystemand the tunnel cryogenic system. Accommodationshavebeenmadefor future installationof a liquid helium circulationpump.
3 Liquid helium storagesystem: Two 115,000-literdewarsprovide liquidstoragecapacityto hold the entire liquid inventoryof the magnetsin thesector.
4 Nitrogendewarand gasgenerationsystem: Provides liquid nitrogenforprecoolingin therefrigerationsystemandwarm gasgenerationfor useinregeneratingtheadsorberbeds. Thedewarcapacityis sizedfor two daysofnormal sectorusage.
5 Auxilialy equipment: Oil brake skidsif oil bearingexpandersare used;regenerationskidsto regenerateadsorberbedsin thecoldbox, dehydrationregenerationskid to regeneratedehydrationbeds,dehydrationunit formoistureremoval from the helium 1oop, additional utility stations,utilityvacuumsystem,andan additionalinstrumentair receivertank.
6 Piping network: Warm and cold piping systemsinterconnectingthecoldbox, the surfacedistribution box, the dewars,theregenerationskids,andthedehydrationskid.
7.2 COOLING SCHEMES OF THE CRYOGENICS SYSTEM
To illustrate therefrigerationloops and otheroperatingmodesof the cryogenicsystem,
flow diagramsshowing critical details of the valving and equipmentthroughoutthe
cryogenic system are provided in many of the sectionsthat follow. For example,
Figure 7.2-1 shows two simplified magnetstrings, the cold compressorbox, the surfacedistribution box, the liquid helium dewar,the coldboxwithout detail, and a simplifiedcompressorsystemalongwith thegasmanagementvalves. Not shownin thediagramsare
the utility system,auxiliariessuchasregenerationskids for the variousbeds,etc. The
valve numberingschemeis given in Tables7.2-1 through7.2-7. Generalsystemprocessrequirementsarediscussedlater.
The valve numberingschemepresentedbelowpertainsto the flow diagramsin thisdocumentonly, for thepurposeof explaining theflow loops and operation;it is not theactualvalvenumberingschemefor thecryogenicsystem.
59
Table 7.2-1. SCS cell valve numbering schemeValve No. ValveDescription Location
V-i Cooldown SPRA, SPRF, SPRI, SPRE. SPRT, SPRE
V.2 Quench SPXA, SPRA, SPRF. SPRI. SPRE.SPRB.SPBT
V.3 Recoolerlevel control SPR
V.4 Power leads SPRF, SPRE
V-S Bymss leads SP
V.6 Quadbypassleads SP
V-7 Correctorleads SP
V-8 LN2 injection to GN2 SPRI, SPRF. SPRE
Table 7.2-2. SCS section valve numbering scheme
ValveNo. Valve Description Location
Iv-! LN2 isolation SPRI, SPRE, SPRF,SPItS, SPRT, or U-tubes
]TV-2 LN2 isolation SPRI, SPRE, SPRF,SPRB, SPRT, or U-tubes
1V-3 ON2 isolation SPR1, SPRE. SPitE,SPItS, SPRT. or U-tubes
IV.4 ON2 isolation SPRI. SPRE, SPItE,SPItS. SPRT. or U-tubes
IV-5 N2 recoolerlevel Next to SPRI
Table 7.2-3. SCS sectorvalve numbering scheme
ValveNo. I Valve Description Location
FEED VALVES
V.3001 LIt feedcontrol upperring Undergrounddistribution box
V.3002 LHe returnupperring Undergrounddistribution box
V-3003 GHe return upperring Undergrounddistribution box
V.3004 20 K returnupperring Undergrounddistribution box
V.3005 LN2 80 K shieldupper ring Undergrounddistribution box
V-3006 ON2 80 K shield upper ring Underground distribution box
V-301 I LHe feedcontrol lower ring UndergrounddistributionboxV.3012 LHe returnlowerring Undergrounddistributionbox
V.3013 GHereturn lower ring Underground distributionboxV-3014 20 K feedcontrol lowerring Underground distribution box
V.30 15 LN2 80K shield lower ring Undergrounddistributionbox
V-3016 0N280 K shield lower ring Undergrounddistribution box
V-3051 LHe supply to returnbypass Undergrounddistribution boxV.3 103 Cold compressorbypass Cold compressorbox
60
Table 7.2-3. SCS sector valve numbering scheme.cont’d
Valve No. I ValveDescription Location
END VALVES
V.0815 LHe turnaroundcontrol Aux end box, next to SPRE
V.0812 LHe feed string isolation Aux endbox, next to SPRE
V.0813 LHe returnstring isol Aux endbox, next to SPRE
V-0811 OHereturn string isol Aux end box, next to SPRE
V.0801 20K turnaround Aux end box, next to SPRE
V-OS 14 20K string isolation Aux end box, next to SPRE
V0821 LN2 stringisolation Aux end box,next to SPItE
V.0822 ON2 string isolation Aux end box, next to SPItE
Table7.2-4. SCS surfacedistribution valve box anddewar
Valvenumber Valve Description
V1513 Precoolerfeedfrom dewar
VISOl Liquid helium feed to precooler
V 1507 Main liquid helium returnto cooldownline crossover
V 1503 Main liquid helium returnto main Lile feedcrossover
V 1505 Main liquid helium returnto dewar-control
V 1504 Liquid helium feedto dewar-control
V1506 Distribution valve box cooldown
V1502 Main liquid helium feed isolation
V1510 2OKreturnheatexchanerbypass
V1509 20K main returnisolation. -
V 1508 20K main feed isolation
VlSi! 20Kfeedtoietumcrossover
V 1532 Dewarvaporreturn - presscontrol
Table 7.2-5. Surface4-80 K coldbox valves
ValveNo.
V 1462
V1461
V 1452
V 1451
V 1443
V 1442
V1441
ValveDescription
Main feed line to warm heliumcrossover
20K to main feed crossover
J-T control valve from coldboxto irecooler
J-T control valve from coldboxto dewar
High pressurefeed to main feedline for tunnel cooldown
20 K feed from turbine 3 control valve20K feed from turbine 2 controlvalve
61
Table 7.2-5. Surface4-80 K coldbox valves,cont’d
Valve No. Valve Descriton
V14 11 20 K return to cooldownreturncrossover
V142! GRe return to cooldown returncrossover
V!43! GHe return to LP coldboxselector4.5 K
V 1432 GHe return to LP coldbox selector 6.0K
V 1433 OHereturn to LP coldboxselector8.0 K
V 1434 GHe returnto LP coldbox selector10 K
V 1422 Cooldownreturn to coldboxselector14 K
V!423 Cooldownreturn to cold box selector 22 K
V!424 Cooldownreturn to cold box selector 36 K
Table 7.2-6. Surface 80-300 K coldbox valves
ValveNo. Valve Description
V 136! Warmheliumfeed to cooldownline FTP
V!362 Warmhelium feed to cooldown line HP purified
V!363 80 K helium from coldbox to cooldown
V!351 80K helium HP to MP bypass
V132! 80K helium cooldown return to LP crossover
V!322 300 K helium cooldown returnto LP crossover
V 1323 300 K helium cooldown returnto 20K crossover
V 1324 300 K helium warm return to 20K suction crossover
Table 72-7. Surfacecompressorandgasmanagement
Valve No. Valve Description
V1003 MPtoLPbypass
V1001 MI’ to 20 K suctionbypass
Vi002 HP to MP bypass
V!004 HP to 20 K suction bypass
V 1005 HP to gasstorage
V 1006 Makeupto MY
V1007 Makeupto2oK
V 1008 Makeupto suction stageI
V 1009 Gassflageto warm headerfeedcontrol
V!0l0 Makeup from warm returnheader
62
4.0 K cooling of the magnet string Fig. 7.2.1
Nominal helium flow of 400 g/s at 4 bar from therefrigeratorsystemcoldbox is suppliedto the precooler. No helium pump is usedfor this purpose.Theprecooleris locatedin thesurfacedistribution box. The subcooledstreamexiting the precoolerat 4.45 K is carried
through thevertical shaft transferline in thesectoraccessshaftdown to the tunnel to aheatexchangerlocatedin thecold compressorbox. Therethe 4 barhelium is subcooledto4.0 K beforedelivery to the undergrounddistribution box by exchangingheatwith the
vaporandthesingle-phasehelium streamsreturningfrom themagnetstrings.
In the tunneldistribution box, this 4 bar flow is split equally, supplyingeachof thefour strings with 100 g/s. Each helium streamis recooledin the SPRF feed spoolrecoolersbeforeenteringthe first celL This helium flows throughthemagnetcold massto
removetheheatgenerated.Thesupercritical flow througheachstring is recooledevery180 m by recoolerslocatedin spoolpiecesSPRA. At thefar endof eachstring in the
SPREthe flow is returned throughthe liquid return line, which is mountedalongsidethemagnetcold mass in the cryostat. The returninghelium suppliestherecoolers,locatedalong the string. Boil-off from the recoolersis collectedin thegaseoushelium return line
andreturnedto thecold compressorbox.
During full load operationof the collider a total of 264 g/s is expandedinto the
recoolersin eachsector. The excessliquid helium from the return line is expandedto
saturatedliquid in the surfaceprecoolervesselandis usedfor precoolingthe heliumflow to
the tunnel. The control valve on the single-phasereturnline in the surfacedistributionboxis usedto control thepressureof thestreamsin the magnetstrings.The main J..T valve
V.1452 on thecoldbox is usedonly asabackuppressurecontrol for the supply stream.The valveon eachfeedline controlsthe flow of eachsupply stream. The control valveonthe single-phasereturn line in the surfacedistribution box, together with the liquidconsumptionin therecoolers,maintainsthetpacrossthemagnevstringandprovidesthe
100 g/s helium flow througheachstring.Excessliquid producedby therefrigeratoris diverted to the dewarvia a parallelJ-T
valve. The vapor is returnedfrom the recoolersat approximately0.77 bar. It is thencompressedby a cold compressorto 1.45bar and returnedto the main coldbox. Thereturnvapor streamsfrom thedewarand from thecold compressorflow arecombinedatthe appropriatetemperaturesandpassthrough the low pressuresideof the heatexchangersto thefirst-stagecompressors.Theoperatingschemeof this cooling loop for the HEB is
slightly differentbecauseof thehigherheatload.
Lead cooling Fig. 7.2.2
Liquid is tappedoff along thestring for cooling of power leadsfor themain magnetsandcorrectormagnets. Valvesatthe warm endof the leadscontrol theflows throughthe leadsto minimize the 4K helium consumptionwithout dangerof burning out the leads. Amaximum of 36 g/s persectoris used to cool the leads. Theleadcooling flow is returned
63
to the warm helium returnheaderin the tunnel. The warm gas is returnedto the first-stage
compressorsthrougha vertical line from the return headerto the refrigerationplant.
20 K shield Fig. 7.2.3
In order to cool the 20 K radiationshieldsin thecryostats,a helium stream is tappedoff
the appropriateexpanderoutlet flow at a temperatureof 14-15K and suppliedthrough a
separatecircuit at 3barnominal pressure.Theflow is divided into two lOOg/s streams.
One 100 gfs stream passesthrough the lower string 20K shield designatedLine 4 and
returns through the upperstring. Theother lOOg/s passesthrough the upperstring and
returnsthrough the lower string in theotherhalf of thesector. In thenominal operating
case,the lOOg/s flow travels a distanceof 8.6km, and the expectedload througheach
loop is 5kW for a total of 10kW per sector. The return flow is brought back at 2bar
througha separatepassin the upperheatexchangers.The 20K loop pressurewill be
maintainedbelow the 4K looppressureto avoid any leakagefrom 20K to 4K. During a
quenchthe 4K magnetcold massflow may alsobe ventedinto the20K shieldline.
84 K shield Fig. 7.2.4
A nitrogencooling ioop providesthe cooling for the84K shield of the magnetcryostats.Two nitrogen lines run througheach cryostat,onecarrying vapor and the other liquid.
Cooling of the shieldis accomplishedby recoolingtheliquid nitrogenstreamwith recoolers
alongthestring and with the injection of liquid into thenitrogenvaporline; thus the vapor
line operatesasa continuousrecooler. The vaporproducedin therecoolersis returnedtothe surfacerefrigeratorfor helium precoolingand is ventedto theatmosphereat 300K.
The 84 K shield cooling systemwill not be describedin detail here,but thereadershouldrefer to the publication entitled: "Nitrogen Systemfor the SSC," cited in Section 2.2,
above.
7.3 OPERATING CONDITIONS AND PRESSURE DROPS
Single-phase 4K helium - Line 1
The flow rate of the single-phasehelium through the magnetstring is designedto be100g/s for both thecollider andtheHEB. Dueto heatload, thereis a temperaturerise inthe single-phaseflow betweenrecoolers . The recoolerscool the supercritical flow to
4.05K, the highestrecoolingtemperatureallowed. At designconditionsthe predictedpressuredropfor a 4320m string is 0.5 bar this excludesthestatic head which can be asmuchas-0.18bar. Thetemperaturechangesin thearc cellsresulting from thepredictedheatloadsare shownin Figures7.3-1 and7.3-2. The distancebetweenrecoolersin thecollider is l8Om and in theHEB 65m.
64
SURFACE
TUNNEL
I
-,
-l
3I VI5]2Ø- rtt
L,!_ JX I’’"9
I__
A1Pt L. I I 1.1517
__________
- -*4---
LJ!.S COLD COIJPRESSORBOX
V31LW
____
[
-I
CR
FIGURE 7.2-1 4.0K REFRIGERATION LOOP
- ‘*v-l0I4 O VI7 *II4I5
V-l2 V-I’ll
0-1004
S
Vl36i
V-I,,,
rI-
L’LI
V1224
V1%3
-t
300K - BoxCOLD BOX
V.’,,’
V-I’ll
]
lip 201< LP1......_....-I I V1404
I V.1441 I I-*4I I 01423
-*4--u cs v’’ -IttI I I -*4--
- .4% I__. VIII?V.1443 BoX - 4K COW BOX WIll?
____
V-14RL<
I L0-1431
I;t-
V_I4514* V142 I -
V_Nil
_____________________ _________
-
__________
V
VII4
-V1513
VlI V151?
E SURFACE DISTRIBUTiON
V15R V-46
P1
_15U
‘00-n
A
LV.
lOX
---I
--I
-t
1
I
II
B
-*4
--t. LEAD
I iI .‘.V_I V-I
-- ---
a’
SURFACE
TUNNEL
- -rn.
Il ., I-
v-nI
IIJI
I WIl laudkm.. klfl
I
*
- I
*1
a
L’I v.4 4 I
j1
Ii
1II L..J .cctr. t.i wcnz L__J .tcwn L.._JI V-_I.
:: ;I *ECflEi aCE a it ti -
V.ll I I I I I I I I- u ! ! Iud,
II TUNNELI DISTRIBUTION - v.r
IBOX .00.
L JtEAt
w.iuwI
II III...$J
IC vA ICLIIA *CTIS ICAI
SIrt.I i iit.I N-401t*
1 I! Vt -IL
-
v-lAO *V-IIA
SURFACE
TUNNEL I
I..-,
IflI
Ia’ I
TUNNELDISTRIBUTIONBOX
FIGURE 7.2-2 LEAD COOLING LOOP
300K - 80KCOW BOX
V-I’ll
VIl
CR I51
1311
.-2
A
A
B
H
H-!
W131?
CII i3" I______
V.AI9
-
v-00l
WI’l4
V.,,,,
-
W1311 L
-t
]-I
- j-Ir
HP lAP 20K LP1_______
I V.1441
I - ‘ I V.4423 V-JIll
WN42I
I - I-*o---.---- VIII?
IV1443 /__J 80K - 4K COLD BOX V-Ill?
V.14311*11
:400 1o-ç:IIIIIT±II: TTTLTTTT±1 ITT
lilt H.I I !:-i V 31’ V VI?
II
p0-1514
I I I v- £ PHCCI.E I V.15k
I SURFACE DISTRIBUTION BOX
I IL..tI_¼_.
D
V.1344 0-17k
I
rT:::o:;::TTTTT
!..T1FB
ii t1ti"n’Efr -H..,
1©IflIkLflnVIIII v-il II IL I J
-1311
7k-I,
‘H
-
SURFACE
TUNNEL
a
r - -V42
‘r i---
1iIF iIi-n444 I-l
- *-.iI -, r ‘4- -
I v.,_VtI I I I I I I
__________
IIl-V3 I-V41 I I I I
II4111
____
1 Il. 1i Ifi
V7k lEan LJ *rc-’
I V-*IH
_________________________________________________
I
__________________________________________________ ___________________________________________________ ______________________________________________________
V.31111 r, r-- -, r----,,1.. -- -
: 1’
______ ______ _______
.?,i I I I I
_________
- -t.tl-- -
L -J
LEADc-lH
V-Il’ $1 1*1 *1
::: ‘rft ii Ij. II IL .11 I[
oral?
Ill IC.Th Iflhlfl ICIXH
V.’
i. -
-
I.
-
V-WI L___
t
L..
j
80K - 4K COLD BOX V-1434 HV1437
V-1431 E*1
L t’’V1131j+<
vII3 V.4411 1 -
131 WI!]?
EKS,3; 1. Th
I , 1V1D1104I
Isw %Lhl
flZCIaEI V.13k
I V-ISI4
I
V.4500 SURFACE DISTRIBUTION BOX
V-CAl V.4313 0-1502 V.47k
-.4-----
I TUNNEl.
I DISTRIBUTION
IBOX -
L.
_ -V04
kKI 14402 t
‘I
II
-
I
- j1
CR
g IV.4400
V1111
[
I cAvtI I I II II-V8 I.V41 I I I I I
3V.4IF
t_j ItflE31 JI
V.1111
k211Th1Nil
I
____ ____ ____
V30I4I r--- r-,
Vj5 I
______ ______ ______
zIII IV-SIll I
JOEl!!? .i I I I I
*1 -
- - -I
flI[ JI[K15k III II IL II IL VIIZZ 3
LEADtIP00
i4_1’
--kt
to VIllI IC_Hal ICtI
L..±
tHCAXR
L..4J
tL..4.J
t
r
V-1313
3001? -
COLD BOXV-I’ll
-Ni-
.
HP liP 201< LF L-043......I V.1121
V.4414
-t -N-
VIII?
V
V.4413-N-
VIII?
.--.2
931
7k-11
‘H
L
B COLD COMPRESSORBOX
:..L:SURFACE
TUNNELII.
AV4nHSI1
IV-3113
SURFACE
TUNNEL
C Hlfl IC_PMa’ 14*021
.4002
A
S
H
*1
FIGURE 7.2-3 20K SHIELD LOOP
V-lAO *DVlIH4
ItICI.
IILUCIIIIII
I"’ I- _
-
TL4- -I
-t- --
®tI I SL.J
I - I%LatlL
I * - - -
I
_ __
I - - -
I - - - - -
I - - - -
_____
I ‘HElfl
I
_____
I NICK KIlS ZI TUNNELI DISTRIBUTIONI BOX 0 It’SL.
FIGURE 7.2-4 841< SHIELD
rVILVEI
"-‘3
- J_1
CR I
51
1113H
-
SV.0,3
I lUll
V-I’ll
I V.4111 II I V.4423
I 0.4442 I
_________________
: I II II - -Ni II V-14l2 801? - IX COLD BOX V.4434
V.4422
I B
_________I
V.4433
I A V.1432111<
I L V.4453 V.44315b11
° 4- V.443 4T V-Ill? -
____
0.1441
_______ ___ _____________
-
V.4414-N
-NV-1402
V
V.4421
0-1411
131j V.453?4
________ _____J____
L11WM4 3; V-lIE
K r"; oS.J PlEat? II
V-13I4
A V-CAl SURFACE DISTRIBUTION
I -‘ V-lId] V-Ill? 01546
I____L . -SURFACE
TUNNEL
BOXLV-
‘.4,?’
3l6l
V
0-3111B COLD COIFRESSOR BOX
V-SI-
-5
___
A V-3II42 IIIV-,,.,
V4111
P.2
V.1311
V ‘HIll HElPSA-LIIIa.’I .‘. VALVE
V-I
SURFACE
TUNNEL
I I
i±’ 1.
- V-llT V4+r
K1 ..I I
I II II II I
-T
ll4GVHLV **r"rn v-Il
iI-r
I.V4I
I I -- II I I
iI I{V-n4.4
r -l rI I
I I,r A r4L J +L V.4114
1 r
-11k
*ri V.H4IjI.4T’T1 4i-i LI
a5 L "‘ L___JI V11
.3
I- r
V.3114 I
V.31111 r,
ElUFIPS 4c3l1 1!I 41r,
ii- F-
-3
--
-- H-
I $1 I
I I IHEECOLE?I I I
I I
LEAD t tC131LI100 10 VIAl ICLIlS Hfll lAMER
I IL .iI IL
I *1 I Vt4111
I. - -
Vt3
Temperature variations in a colilder cell located on the right side of the feedat the end of the string where the recooling temperatureis the highest.
For a similar cell located on the left hand side of the feed, the highest temperature
expected in the last dipole is higher by 14 mK.
For a cell located on the left hand side of the feed and starting with an isolationspool the maximal temperature is higher by 14 mK as above, plus 20 mK due to theheat leak in the SPRI and U-tubes Which are located after the recooler.
The expected change in the recooling temperature between the Feed-Spool to theEnd-Spool is 50 mK.
The designed temperature approach in the recooler is 50 mK.
4.21
4.19
4.17
4.15
4.13
wI
4.1102a.E02
F-4.09
4.07
4.05In
00E E
in in in It It in- - * - -4 -00 0 cc cc14 in L It in It- - - i4 -
L 0
InN
.ItIt
llL4
E E EE EIt It In It It- - * - -
*0 00 *0in .4 o11ç .4- - - -
o o o 0
EIn-4ait-
0
EEItIn00 N
-
04Ct
Figure73-1. Temperature changes in an collider arc cell
Temperature variations in a HEB cell located on the right side of the feed at the end of thestring where the recooling temperature is the highest based on preliminary design ofmagnets with cross flow cooling.
For a similar cell located on the left hand side of the feed, the highest temperatureexpected in the last dipole is higher by 14 mK
The expected change in the recooling temperature between the Feed-Spool to the End-Spool is 50 mK.
The designed temperature approach in the recooler is 50 mK.
4.35
4.33
4.314.29
4.27
4.25
4123
4.21
4.194.17
I.=
02a.EVF-
- ItM
I. ThMERATVRE IN TillERATURE IN TH]
ANNULAR PASSA-
INTERCONNEC1
E
...ifl4%flVflI --
er
//4/
-
--
fr-
4.15
4.13
4.11
4.09
4.07
4.05 F
c
FN.-4
:
FNW
-4
:
FEcONU
fleir
FN.4-4
t
FN-4
±=
FEit
eP’
:.
Figure73-2. Temperature changes in an HEB cell
Single-phasereturn 4K helium - Line 2
The single-phasereturn line carriesthe single-phaseflow exiting themagnet string to the
surfacerefrigerator system. The returningflow is throttled into the recoolersalong the
string,providing refrigeration to thesystem. Theamount of flow exiting the string at the
end of the sectoris equalto the amountof thefeedflow minusthe leadcooling flows. The
amountof flow lost to leadcooling is about9g./sper string. At nominal loading the amount
required for refrigerationwill be around264 g/s per sector;thus thetotal flow returningto
the refrigeratoris normally -lOOg/s or 25g/sper string. Undernominal conditions, the
pressure drop through Line 2 is under0.03bar for a string length of 4320m.
4K vapor helium return - Line 3
Thevaporreturn line, Line 3, collectsthe boil-off vaporfrom all therecoolersdistributed
along the string. The flow rateat theend box is zero and by thetime the flow exits the
string it will havegrown to a value in therangeof 68 g/s for thecollider and212 g/s fortheHER. Requirementsof the operatingtemperaturelimit thepressurechangesallowedthroughthis line. Theoverall changeallowedis 5kPaper string.
20 K helium loop - Line 4
In a collider sector,undernominal operatingconditions,a flow of 100g/s at 3 bar, 14Kis suppliedto one string andreturnedthrough the secondstring at 2 bar and about 24K,
all within thesector. In theHER, theflow throughthe20K helium loop originatesin oneheliumplant and is returnedto the secondhelium plant.
SO K liquid nitrogen loop - Line 5
This line is usedto refrigeratethe 84 K shield. It is also usedfor distribution of liquidnitrogen supplied to the whole systemat two collider locations,at a total feed rateof4*7 kg/s. The expectedmaximumflow rate per line undernormalconditionsis 1.2kg/s.In certainpartsof thesystemthelocal flow rateneedsto be increasedby meansof sectorcirculation pumps. The heatabsorbedby the liquid nitrogen is removedby recoolers
locatedat the endof each1080 m section,and by a continuousrecoolingsystembasedoninjection of liquid into the vaporreturnline.
80 K vapor nitrogen return - Line 6
This line is usedto return theboil-off vaporfrom thenitrogenrecoolers. It is alsousedasa continuousrecooler by injecting liquid nitrogen at sectionboundaries. This type ofrecooleris possibledueto thedip or inclihation of thewholecollider. Detailsaregiven in"NitrogenSystemfor theSSC,"cited in Section2.2, above.
71
8. DESIGN REQUIREMENTS AND DEFINITIONS OFOPERATING MODES
The following are theprimarymodesandoperationalrequirementsof the SCS. Thedesignof thesystemmustmeettheseoperatingmodesandrequirements.
Normal operating modes
Thesemodescover the steadyoperationof the systemwithout the beam,thechangeinoperationwhenthe beamis turnedon, andthechangein operationwhen thebeamis turned
off.
Minimum/maximum capacity modes
For the minimum mode,the systemis operatedat the lowestcapacitythat will maintain
equipmentat liquid helium temperaturesand will processdewarboil-off. The minimum
mode is achievedby operatingtheplant with a the leastpossiblenumberof compressors
andexpanders.In maximumcapacitymode,all compressorsand expandersarerunning exceptfor
redundantorspareequipment.
Utility modes
Thesemodescover the warm gascirculation for cleanup;the cooldownfrom 300K to4 K, magnetconditioning,emptying of the sector,and warmup of the sectorand theproceduresrequiredfor magnetrepair.
Featuresand requirements
Thefollowing featuresof therefrigerationsystemarerequiredin orderto operatetheentirecryogenicsystem. The systemmustallow for theadjustmentof the local capacity,andmust allow fast transitionbetweentheoperatingconditionsof therings. Therefrigerationplant mustoperateefficiently over a wide rangeof operatingconditions. Thesystemmustbe designedto be reliableand a redundancyschememust be providedto allow operationduring equipmentfailures. The systemmusthandleupsetconditions,suchasquenches,without any severeinterruption to its operation. The magnetsystemmay releaseaconsiderablenumberof contaminantsduring its operation,and thecryogenicsystemmustbetolerantto this discharge.
8.1 CAPACITY ADJUSTMENT, EFFICIENCY, AND GAS
MANAGEMENT SCHEME.
Thedynamic load ofthe collidercontributesto abouthalf the4K refrigerationheatload onthecryogenicplant When thebeamis down,the loadon the plantis reducedto lessthan
72
half, and when a sectionis underrepairthe load is considerablyless. In order to haveacost-effectiveandefficientoperatingschemefor the collider, therefrigerationplant mustbecapableof efficientturndownwhenrequired. In the plant’sbasicrefrigerationmode, it willbe capableof operatinganywherebetweenthe maximum capacityand the minimumcapacityobtainablewithout bringing a compressoror expanderoffline. Within this range,the gasmanagementscheme,togetherwith thecoldbox control scheme,will allow theplantto turn up anddown accordingto thedemandsof the loads 4K refrigeration,liquefaction,and20K shield.
The responseof the refrigerationplant to thedifferentloadsis determinedby themaincontrol loops-inparticularthegasmanagementsystem-andthis responseis summarizedasfollows:
a. First-stagecompressors:Flow to thefirst-stagecompressorsis fed from:
1 theflow returningfrom thecoldbox low pressureside,
2 themakeupfrom gasstoragecontrolledby V-1008,and
3 the leadcooling flow controlledfrom the wannreturnheader,V-lOb.
To preventthe suctionpressurefrom droppingto a subatmosphericlevel,thereis a bypassacrossthefirst stagethroughvalveV-l00l that keepsthefirst stagefully loaded. Thenetmassflow contributionfrom thefirst stageto the secondstageis equal to the net flow to the first stage1 + 2 + 3,above.
b. Secondstagecompressors: Thesecondstagesuctioninterstagepressurevariesaccordingto themass flow to the secondstagecompressors.Thisflow is the sumoftherecyclemassflow returnedfrom themediumpressurepassandthenetmassflow contributionfrom thefirst stage.
For small loads the suctionpressureof the secondstagedropsto the levelcontrolledby thesecondstagebypassV-l002. Whenthecoldboxsystemandcompressorsystemreachtheequilibrium necessaryto handlethis load,eachexpandersettlesto its own operatingcondition and the dischargepressureof thesecondstagecompressoris at a valuedeterminedby the netinventory in the coldbox. As a result, the secondstagecompressorpressuressuctionand dischargesettle to therespectivevaluesrequiredtohandlethis flow.
c. 20K compressor: At steadystate the suction pressureof the 20Kcompressoris determinedby therateof flow returningfrom the20K shieldloop. The dischargepressureof this compressoris determinedby thesystemdischargepressurenecessaryto handlethetotal load asdescribedinthepreviousparagraph.
73
The gasmanagementbypassvalvesare:
a. Medium pressureto low pressurebypassV-lOOl. This controls theminimumpressureto which thefirst stagesuctionis allowedto drop; asaresult,thenet flow from the first stageinto the secondstageis equalto theflow from theload returnplus makeup.This valve is alsousedfor runningthefirst stagecompressorsindependentof the coldbox and is sizedfor fullflow bypass.
b. High pressureto medium pressurebypassV-1002. This controls theminimum pressureto which the secondstagesuctionis allowed to drop,and is also usedfor runningthe secondstagecompressorsindependentofthecoldbox. It is sizedfor full flow bypass.
c. Medium pressureto 20K suctionbypassV-l003. This allows the systemto processmore gas when the secondstageruns out of displacementcapacity. V-1003is usedonly if therequiredflow ratesthroughthe 20Kshieldscanbe maintained.
d. High pressureto 20K suction bypassV-I 004. V- 1004 controls theminimum pressureat which the 20 K compressorsuction is allowed tooperate. V-1004is alsousedto run the 20K compressorindependentfromthe coldbox and should be sized for the full capacity of the 20Kcompressorat 4 bar suction.
e. High pressuredischargeoverloadto storageV- 1005.
f. Makeupinto secondstagesuctionV-bOo.
g. Makeup into 20K suctionV- 1007 is suppliedthroughthe dehydrationskid. This allows moisture to be removedfrom contaminatedheliumsuppliedfrom warm gasstorage.
h. Makeupfrom gasstorageto first stagecompressorsV- 1008.
i. Warm gassuppliedfrom storageinto warm return headerV- 1009 forinventorymanagement.
j. Gasmakeupfrom warm returnheaderV-lOb to fir st stagecompressors.Undernormaloperation,this makeupis equalto the liquefactionload.
In summary,therefrigeratorcapacitychangesaccordingto the load total of 4Krefrigeration,liquefactionand 20 K shield. Makeupallowedinto thesystemfrom storageconstitutesan additional load. Changein capacityis reflectedby a changein thesecondstagedischargepressure;this changeoccurswhenthereis a changein thenetequilibriuminventoryin theplant coldboxjcompressors.Any excessliquid producedis storedin thedewar. At lower loads, one or more compressorsor expandersmay be shut down tomaintainefficiency in operationof thesystem. The basiccontrolphilosophyremainsthesamein this casebut thesystemis operatingata lower capacity.
.74
8.2 LIQUID INVENTORY MANAGEMENT AND REDUNDANCY SCHEME
Liquid inventory management
The liquid inventory managementsystemservesas the interfacebetweenthe surfacerefrigeratorand the tunnel cryogenicsystem,and its hardwareconfigurationand control
schemeare critical for smooth operationbetweenthe surfacerefrigeratorand a very
demandingcryogenicload. The liquid inventorymanagementsystemmust be able tohandlethe following minimumfunctions:
a. Managethesingle-phasereturnflow. Thesectorrequiresa circulationflowof 400g/s. Under normal operatingloads, the single-phasereturn flowfrom the 4 K refrigeration loop is returnedto the surfaceprecoolerV-l5 14, andadditional precoolingcapacitycomesfrom the refrigeratorindirectly-thatis, via JT-valveV-b45b into the dewar,andfrom thereviacontrolvalveV-i 513 into theprecoolerbath. This configurationallows therefrigeratorto deliver extraliquid into thedewar. Theflow to theprecoolercan be deliveredfrom thedewarindependentof therefrigerator’scapacityduring transients. Normally all the return flows are flashed into theprecoolervia V-b5b4. During transients,excessflow is returnedto thedewarvia pressurecontrol valveV-b505.
b. Control pressureduring transientssuchasquenchesand inventorychangesof the sthngs: Pressurecontrol valvesV-1504 and V-1505 allow flow tothedewarfrom boththe single-phasefeedand the returnline.
c. Interchangesingle-phasefeed andreturnflows. This reversesflow throughthe magnetsstringsfor instrumentationcalibration. V-b502is closedandthe single-phasefeed is suppliedthroughV-i503 with thereturnhandledthroughV-1504. Mostof theprecoolingsupply comesthroughV-i513.
d. Allow the liquid helium storagedewar to act asa storagebuffer. Excessflow from the single-phasereturn not usedfor precoolingis storedin thedewarvia V-i 505. Additional excessliquid from therefrigeratoris sentviaparalleliT valve V-i45i to thedewar.
e. Allow theliquid helium storagedewarto actasacapacitybuffer. Whentherefrigeratoroutputchangesat a rateslowerthanthe load, liquid from thedewaris usedfor precoolingof thefeed streamV-1513. This allows thesupply flow rate to be increasedwhennecessaryfor loadvariations.
f. Allow transferof liquid helium from neighboringsectors.Whenadditionalliquid inventoryis requiredfrom neighboringsectors,V-15l4 andV-15O5can be usedto lower the local systempressure,andallow theneighborstotransferliquid into thesector.
g. Maintain thecirculationflow throughthe strings in therangeof lOOg/s perstring and a pressurehigherthan3 bar.
75
Redundancy scheme
In theeventof failure of any expander,the systemmustcontinueto operatewith at leastthesteady-statenominal loadcapacitygiven in Table9.2-2. Someliquefactioncapacitymaybeborrowedfrom neighboringplants. This requiresthateachsystembe designedwith excess
capacity. Dueto theflow rate limitations of the cold piping in the magnetstrings, it isdifficult to transfer4K refrigerationbetweensectors. However,liquefaction loadscanbetransferredrelativelyeasilyby shifting the warm gasflow to neighboringsectors-thatis,
the neighboringplant takesmoregasout of the warm return header. Single-phaseflow is
transferredfrom one sectorinto theotherat the sectorboundaryin the auxiliary end box
through a flow controlvalve. Becauseof the liquid inventory in thesectordewarsthereisno needfor immediateaid from theneighboringsectors. Capacityand inventorycan alsobe shifted betweensectorsby handshaking20K flows acrosssectorboundaries. In thiscase,themaximumallowableimbalanceof the20K flows in therefrigeratoris determined
by the remainingliquefactioncapacityof theplant
Therefrigeratoris designedto provide 15kW of cooling to the20K shield at 4bar
supply pressure. The nominal load for an averagesectoris 10kW. Two neighboringplantscan togetherprovide20K refrigerationto a sectorwhenrequired. In this caseoneleg of eachneighbor’s20K loop will be approximately17 km long.
8.3 CONTAMINATION TOLERANCE
Sincethere are 16 km of magnetcoils and laminationsconnectedto eachplant, it isreasonableto expectahigh level of contaminationandimpurities,andthesystemshould bedesignedto be insensitiveto these. Appropriateadsorberbedsmustbe provided in thecoldbox and 20K loop. Tracegasesareremovedin adsorberbedsat 80K and 20 K. Inorder to removemoisture,a mole sievebedis installed inline on thereturnstreamof the20 K loop aheadof thecompressor.This mole sieveis usedduring nominal andlow loadsand during cleanupand cooldown to 80K. Moisture not removedby the beds iscondensedin the 300K-80 K heatexchanger. To allow the systemto operatewithoutinterruption while the first heatexchangeris being derimed,a second,parallel,300K-80 K full sizeheatexchangeris required.
Sincethe initial chargeand all makeuphelium are suppliedto thesystemasliquid,thereis no appreciablesystemcontaminationfrom the helium supply itself However,warm gasthat may be contaminatedwith moisturemust first be processedthroughthedehydrationskid.
76
8.4 QUENCH TOLERANCE AND RECOVERY
The refrigerationplant and systemmust toleratethe quenchof singleand multiple half-cells, and must support rapid quench recovery. The main concernis protection ofexpanders. A cold buffer volume connecteddownstreamof the last expanderis onepossiblemeansof protection. The helium returningthrough the single-phasefeed andreturnlines to the surfaceis sent to thedewar. During a quench,a portion of thehelium
from the 4K loop is ventedinto the 20 K loop. The 20 K expandermust continue
working andmustdischargeits flow to thecoldbox insteadof to the 20 K feed line. On
the 20K return side, an independentpassthrough the heat exchangerstack to an
independentcompressorallows thepressurein the 20 K systemto rise, minimizing theeffect on the rest of the plant. The increasein suction pressureallows the 20 Kcompressorto processmoreflow during quenchrecovery. Excessinventorythat cannotbereliquefiedby the refrigeratorgoesto warm gas storage.
8.5 CLEANUP, COOLDOWN, FILLUP, AND WARMUP REQUIREMENTS.
Separatelines that bypassthecoldbox on the supply andreturnsidesarerequiredto handletheflows during cleanup,cooldown,and warmup.
For cleanup, the plant provides clean warm gas to the system. To removecontaminationfrom thehelium stream,thehelium is cooledto 80K. Cooling the helium to80 K allows impurities to be adsorbedin the 80 K beds. The helium is then warmedto
ambienttemperaturebefore it is sent back to the system. To allow for this mode ofoperation,certain bypassand control valves are requiredin the plant: a bypassvalveV- 1351 from the high pressureto the mediumpressurepassafterthe 80K beds,and acontrol valve V.1362 to regulatethe warm flow to the supply lines of the system.Crossovervalve V-l324 allows thedehydrationunit to processgasfrom the warm return
header.Cooldown from 300 K to 80 K requires450kW refrigeration capacity using
nitrogen. Theliquid nitrogenboiler mustbe appropriatelysizedfor this duty. A controlvalveV-l363 regulatingcold flow into thecooldownline is neededfor this service. Forcooldownto 20K, a crossovervalvefrom the20K expanderto thecooldownsupply lineis required. Crossovervalvesare requiredfrom the cooldownreturn line into the heatexchangerstacksat 80K V.1321and-20K V.1423. On thevaporreturnline from thetunnel cold compressordischarge,crossovervalves V-1431, 1432, 1433, and 1434into theheatexchangerstackatapproximately5 K, 7 K, and 9 K arerequiredto return theflow during upsetconditions,magnetconditioning,and the last phaseof the cooldownprocess.
For warmup,the plant mustbe able to supply cleanwarm gasfrom thecoldbox,orgasobtainedfrom thecompressorsystemafterthegasexits thefine oil removal skid. The
77
sameloop usedto generateclean gasfor cleanupis usedfor the warmup process. Warmgasobtainedfrom the compressorsystemmay be used when high purity gasis not of
concernV-1361.
8.6 EXPANDABILITY
Thecollider is an instrumentunderdevelopmentand someof its operatingrequirements
cannot be known in advance. It is desirablethat provisionbe madefor a futureupgradeinthe systemcapacityto asmuch as 150%of the initial deliveredrating. It is expectedthat
this upgradewould be accomplishedby adding an extra coldbox and additional
compressorsat a later date. The SRS mustprovidefor connectionsfor upgrade-thatis,additional connectionsin the surfacedistribution box and compressorsystem. Theequipmentlayoutsmustalsoallow enoughspacefor additions.
78
9. OPERATING MODES
9.1 OPERATING MODES OF THE REFRIGERATION PLANT
The ninerefrigerationplantsfor the collider andthe two for theHEB are identicalin design
andcapacity. However,variationsin sectordesignresultsin correspondingvariationsinthe refrigerationand liquefaction loads for eachplant. Theplant is designedto handlearangeof situations-whenthe beamis active, or whenthe beamis not active; when a
neighboringplantneedsassistance;whenan quenchoccurs;andwhencooldown,warmup,
or maintenancetakesplace. For eachof thesesituationsthe refrigerationplant operatesin a
differentmode. When the beamis active theplant operatesin normalmode. When the
beamis not active theplant operatesin standbymode. When a quenchoccurstheplant
operatesin quenchrecoverymode. When a neighboringsectorneedsassistancetheplant
operatesin assistmode,and whencleanup,cooldown,warmup, or emptyingneedsto be
performedtheplant operatesin oneofthe utility modes.
Theplant is alsodesignedto operatein othermodes-inspecialmodesfor singleringoperation,andin a minimum capacitymodewhen loadsarevery low. Thesystem’sstatesand plant operationalmodesaredefinedon Figure9.1-1. Thedesignload and thenormaloperatingandspecialmodesaredescribedin this section;theutility modesare describedinchapter10.
The plant is operatingin the normalmodewhenthesystemis cold andthe beamison. In this mode, the load on the refrigerationplant may vary accordingto the beamintensity.
Theplant is operatedin the standbymodewhen the systemis cold with no beamoperatingand thereis no currentin themagnets.In this mode,the loadon the refrigerationplant dependson the static heatload..
Theplant is operatedin the assistmodewhenpartof its capacityis beingtransferredto a neighboringplant In this mode,capacityis transferredby shifting cryogensthroughsectorboundaries.
The plant automaticallychangesto the quench recovery mode after a quench isdetectedin a string.
Theplant is operatedin oneof theutility modesduring cleanup,cooldown,warmup,or maintainance.
Theplant operatesin specialmodesfor different typesof configuration-e.g.,singlering operation.
Theplantis operatedin themaximumcapacitymodewhenthesectorloadsarehigh,or whengasneedsto be processedfrom truck deliveries,or to refrigeratemore than onesectorfor long termcold storageof thering.
Theplant is operatedin theminimumcapacitymodewhenthe sectorheatloadsarelow-e.g., to refrigerateonly onesectorfor long term cold storageof thering.
79
C’
0*0’
te II
:3 I-z
L
Ct
z
ZI
*1=1z
=pi
z
ccCtccUC
zccI-Ccc
STATCS
Irk
PROCESS
I STAW*V
rRLt
*IKSRIUJJCOOL
N - - - _
UOLIAJWN
- - -
Fig 9.1-I. Definition of the Plant Staresand the Refrigeration Plant Operating Modes
Design load Table 9.2.1
Therefrigerationsystemis designedwith a specific capacityto meeteachof the variousnormal loads,to meetall theloadsduring specific upsetconditions,andwith extracapacityto meet redundancyrequirements. The systemis able to reach its maximum designcapacity,given in Table9.2-1,whenall of its componentsare functioningproperly. Thecapacityrequiredfor normaloperationof a nominal coilider sectoris lessthan this designcapacity.
In the eventof failure of any single expander,the systemmustcontinueto operatewith at least the steady-statecapacity given in Table 9.2-2. Furthermore,when aneighboringsector needsassistancein the form of liquefaction or other loads, therefrigeratormustturn up to providethis assistance.Dueto theflow ratelimitationsof thecold piping in the magnetstrings, it is difficult to transfer4 K refrigerationbetween
sectors. However, liquefaction and 20 K loads can be transferredrelatively easily byshifting thewarm gasflow to neighboringsectorsor by handshaking20K flows betweensectors.
This extracapacityallows for quick recoveryafter a quench. During and after aquenchthe recoveryprocessmust begin quickly, with theplant turned up to handlethistransient.
The sectorsarenot all equalin length, asshownin Table 2.1-2. The largersectorwill have capacityto handleits loadslocally, and the shortersectorswill have excesscapacity.Thevarious loadson eachsectorrefrigeratorwill vary from sectorto sectorsee
Figure 5.1-1 andTable 5.1-9.
Normal operating modes
Normalmode- nominal load Table 92-2
In thecouidersector,this is thenominalheatloadexpectedwhenthebeamis on and atfull
power. Theloadfor anominal collidersectoris given in Table9.2-2. This load will varyslightly from sectorto sectorbecauseofthedifferencein lengthand designof the sectors.
Normal operationof theHEB is for approximatelytwo hoursper day. During theremainingtime theFLEE will be idle, in "standbycold" status. It hasa very high dynamic
loadcomparedwith thecollider load, If necessaryduring thenormal operation,heliumfrom thedewarwill be usedandwhenthesystemis in standbystatus,thedewaris refilled.
Thereis only onering in theHEB Fig. 9.1-2,and thereforeits 20K shield loop isrouteddifferently from that of thecollider. Therouting of the the4K loops is similar tothatfor the couider. The HEB ‘S 20 K shieldroute startsat oneheliumplant and endsinthe otherhelium plant, and a similar schemeis proposedfor the collider. If inventoryaccumulatesin oneplant, the20K supply flows maybe temporarilyadjustedto returntheexcessinventory otherwiseinventorymay be exchangedthroughthe warmreturnheader.
81
Standbymode- standbyload Table9.2-3
When the rings arecold andthere is no beamand no current,theonly refrigerationloadsare the static conductionand thermal radiation loads. Flow through the leads is alsodecreased,reducingthe liquefaction loads from 36 g/s to about25 g/s. This is thestandbymode. If a quenchoccurs,theproton beamis dumpedandthe refrigerationsystemin thesectorwherethequenchtook placegoesinto thequenchrecoverymode. Thecurrentsinthe magnetsof theremainingsectorsare rampeddown to zero and their refrigeratorsare
turned down from normal mode to standbymode until recoveryis completedin the
quenchedsector.
Assistmode- assistloadTable 9.2-4
In the event of a moreseriousfailure in one sector-thatis, if more than one expandershould fail to the extent that its refrigerator is unableto handlethe nominal operatingloads-theneighboringplantscan be turnedup to their maximum capacityto take theliquefactionload from the sectorrequiringassistance.In this modetheassisting plantmust
be capableof absorbingat leasthalf the liquefaction load 18Wsof the sectorrequiring
assistance;theotherneighboringsectorwill absorbthe remaininghalf.
Quenchand recoverymodeFigure 9.1-3
In the eventof a quench,the quenchprotectionsystemis designedto dump the storedenergy into specific energydumps. However,some of the half-cell storedenergyis
dissipatedin themagnet windings,causingthemto warm up. When a quenchis detectedin any magnet,a quenchis inducedin theentirehalf-cell 90m for protection. Thehalf-cell stored energy of roughly 8 megajoulesis divided betweenthe helium and thecoldmass,with about3 megajoulesgoing to the helium. As the temperatureandpressureof thehelium increase,the inventoryof thehalf-cell----600liters-mustbe absorbedby the SRSin a few minutes in orderto relievethesystem:The quenchdetectionsystemopensthehalf-cell quenchrelief valve V-2 to vent thewarm helium to the20K shield line, If thewaxmhelium flow is not vented,it may inducea quenchin therest of thestring.
If many half-cellsquenchat any given time, thetemperaturein the20K line dropsandthepressurerises. This low temperaturehelium returns20 K returnline to theplant,exchangingheatwith the 20K feed flow by closing V-i 510 and openingv-i 509. Therising suction pressureon the 20K compressorincreasesits mass flow capacity,thusaiding the quenchrecoveryand the inventorymanagementassociatedwith the quenchrecoveryprocess.Thegasmanagementallows the20Kcompressorto operateat a suctionpressurethatvariesbetween2bar and4 bar. The 4K helium ioop providestheadditionalinventory necessaryto cool and fill the magnets,and to restorenormal operatingconditions. As thequenchedsectionis cooleddown, helium ventsfrom the coidmassthroughthequenchvalveinto the20-K line until it reachesnormaloperatingtemperatures.The remainderof 5 megajoulesper half-cell of energy is removedfrom the cold massduring this recoveryperiod.
82
Excessinventory that cannotbe reliquefied goes to the warm storage. When thesingle-phasereturnflow is insufficientdue to depletionduring the recoveryperiod, liquidfrom thedewar is used to aid subcoolingin the surfaceprecooler. The plant is able toabsorbthe 5megajoulesreleasedby onehalf-cell in approximately30 minutes. During aquenchtheamountof energyreleasedby a half-cell in the HEB ring is lessthan theamountof energyreleasedby a half-cell in thecollider arcs. The amountof energystoredin these
half-cells differs, due mainly to differencesin length. The half-cell of the HEB is only32.5 m long comparedwith 90 m in thecollider arcs.
Special modes
Single ring operation Figure 9.1-4
When oneof thecollider rings is down for a long period of time, it maybe desirableto
operatethe secondring for beamstudies. The downedring may be warm or cold. Theinteraction regions wherethe two parallelcold massesare packagedinto one cryostatrequirespecial treatment. Operationof a single ring in the collider is similar to theoperationof theHEB ring particularly with regardto the 20K shield.
Maximum capacity modes
In maximum capacity mode, all compressorsand expandersare running except for
redundantor spareequipment. Oneexceptionis themaximum20K mode,when all of theequipmentmay not be requiredseebelow. When warm gas is to be liquefied fromexternaldelivery, therefrigeratoroperatesin maximumliquefactionmode. Whencold gasmustbe processedduring externalliquid delivery, therefrigeratoroperatesin maximumrefrigerationmode. To maintain the systemat 20 K or slightly colder therefrigeratoroperatesin maximum20 K refrigerationmode.
Maximum capacitymodesarelistedas-follows;
a. Maximum liquefaction modefor full 100%liquefaction capacity. Theplant will liquefy warm gasfrom storage.
b. Maximum refrigeration mode for full refrigeration capacity duringreliquefactionof vaporduring liquid delivery to thedewar.
c. Maximum 20K refrigerationmodefor maximum20K cooling deliveredtothesystem. Whentherings aremaintainedin cold storage,between10 Kand 30 K, the refrigeratormust be able to providecooling to the 20 Kshield for two sectorsapproximately20kW of cooling. Alternatingplantsmay be shutdown. The 20 K supply pressureis at least4 bar andthe supply temperatureis as low aspossible. Two compressorsmay besufficientfor this mode. Thesparecompressormaybe usedinsteadof the20 K compressorto operatethe 20K suction pressureto 1.05 bar.Operatingat a suctionpressurethis low also allows the systemto processboil-off from thedewar.
83
1
NOI1Y3dQ 1VPIdON 83H Z-L6 3W1011
rI I
I II I
IISLA
L-.
r
lilA
i dO
L
=
Ililt-A
1]NNAJ.
J3YThflS r -
£QA
L tt
t.
cLA ?flI-A
N0W191flS10 ]3YJflS
XO9 OSS3dMO3 01031]N N AL
33YthflS
0C1A t: i li31oO3sd
* -I
LlcI.A
l-A
-LIL*A
NCt,IA
tttIA
-
--tIIA
xoa 0103 t -
t2HA I
---I
1
SO
l_A
IOZ dYI dH L
1 tLCIAL -
riouRE 9.1-3 QUENCH AND RECOVERY
V WO7
v-IesI
v-xl,q
9’
r V.’,’.
/-1371
crL
ibo
v-In’
Mx.’,
v-ia’, I
V.1W
= 3001< - 80KCOLD BOXv-lam
--
IHPI V-lift
-a
__
W1442 t II
_________
I_
_
V1443
:v II
V-l4,IQ j
4.
-I
-
MP 20K LPI_D........... -
V-fillI
BOX - 4K COLD Box V-1434 j.c.c v14V
V1433 DCV-1432
V_I. s< -.-----
_________
1
_____
V14S2
- VIMI V.12
PREtR I * v-aSURFACE
DISTRIBUTION OX
VI2 VI
534 V45OJ
u 9
I I I
‘A’-I-
L
SURFACE
TUNNEL
II
W1413
--
V1412
_--
V141I
a
45110=
rrff
V."’,- --
504
ii4
v-I,o
L
1ICOLD CO&IPRESSOR BOX
CR
S I
k]
S. wc’
V31
5
I -S.
1i
-A *Iv-aa.
S I
I
S
SURFACI
TUNNEL
--I
.V-I
----1 LtAO
‘o’! ---Ti - r---h -
v:In_-a v-4
a - -.v.4 :i II 1 -
I - IUIIotjgc4i
thi1* ‘1 v12
‘Ih"4 t,41 4,1
4’ z
tt’__5
V141
2- ‘ I I - I
I I I I I I II lEn l-v41 I I I I
____
I i1f4LflFt I
1 L___J prcac,l..... L__JI v-_I
V3II ‘
NI iEfZ$ 1ZIt 1’4:
4 I- I I
________ ________ ________
iiI
RtCnERII I I
rn *II I I I I - I I
-l
H
I -
--n1 I--
I
_____________________
III TUNNEL I
I DISTRIBUTION at.fl v-Xfl II I! I I IIIROX
.1
LEADTO V$ CLflJ tn$I *cA
i*irL - - t_ -r v-e I---_..
I
I -
I
_____________________________________________________________________ ___________________________________________________
I
__________________________________
I - - - -
__________
I
___________________________________________________ _______________________________________________________________
vIIu- -
______
Ip
I - I
NUNNEL nw;:1:1II
___________
I DISTRIBUTiON
_______________________________
iBOX.- " I’ I H
LLEADcnDc .0-n- .flla. .cAP
FIGURE 9.14 COLLIDER SINGLE RING OPERATION
Lft::
-‘a
________ _______
LSP .uu ____
___________
3001< - *0K vl22I
Y-IM7V-fl2 COLD BOXI
VIfli
IHP MP 20K L.
-r L7Yi
___
c
____ ____
- - Iv1143 L_____J 80K - 4X COLD BOX
:::::V-I4
LWl4llj.*
-Dcj-..........
v-Ill _I - 1___V149
I -
4
:r*cc D1RlBUTIOt1 Ox
I
- j-1
V1414 I
- I
a CR I
W1412 I
w
Villi
J
33’Ut NM
I YII
L
vnIz Ill
I.-Hx
V.l5 V1O6
SURFACE
TUNNEL
I
-,I I
v-liI
1- 1-’i,i4t’ T
:TT EtI
-
- - -
v13I1
r *S4 lam
rn- 1 I I I
I Ii I
nv-oI v
‘Wi’
a
SURFACE
TUNNEL
carfl7 &NG
-h’Vli
V-2
________
-h’________
_t- UIV-ti
T IiZi 1*
I I - -
I VAL Vt I I I II IV3 I.v.l
V*-:v.4
____
*tCER
VXlJ r-, r-,
V314 Ixnw i _J. I I I
--
_ _
--
-r
___
irit I[ II Ii v4t22
-à2,
Minimum capacity modes
When 4 K cooling of the magnetsthngsis not requiredfor a prolongedperiodof time,
suchasduring repair,maintenance,or cold storageof thecollider rings at 80K or 20K,theplant runsat a minimumcapacity-i.e.,with a minimumset of compressorsonefirstand one secondstage-toprocessboil-off from the dewarand to keepthe 20 K shieldcold. One or moreexpandersmay be shutdown so that the refrigeratorcan run in thismode. In this minimum capacityarrangement,the plant must be able to operatein full*
liquefaction mode,full refrigerationmode,any liquefaction/refrigerationratio mixedmode, or 20K refrigerationmodeatthis minumumcapacity.
9.2 REFRIGERATOR SYSTEM LOADS
Table 9.2-1. Design mode heat loads
P1bw
TIK
HIJIG
SIJIG-K
P0bar
‘10K
LIJIG
SOJIG-K
FLOWg/s
WADW
WearkW
REFR 4.0 4.00 10.18 3.07 0.77 3.95 30.65 8.86 330 6750 574
ui 4.0 4.00 10.18 3.07 1.05 305.0 1599. 31.57 45 320
20-K SYS 4.0 140 83.92 12.60 2.00 27.8 158.9 17.80 200 15000 302
‘IUFAL LOAD CAPACrFY REQUIRED 1196caoCOMPR. 0.75 J__4.3 33.44 9.57 145 6.07 41.76 10.08 330 2745 48
APPROXIMATE TOTAL SYSTEMCAPACITY RECAJIRED 1244
Table 9.2-2. Nominal mode heat toads
P1bar
TIK
HIJIG
SIJIG-K
P0bar
10K
3JIG
SOJIG-K
FWWgis
WADW
WcarkW
REFRIG 4.0 4.00 10.18 3.07 0.77 3.95 30.65 8.86 264 5400 461
LIJff 4.0 4.00 10.18 3.07 1.05 305.0 1599 31.57 36 256
2O-KSYS 3.0 14.0 84.91 13.25 2.00 23.2 134.9 16.9 200 10000
‘TOTAL LOAD CAPACiTY REQUEJWLDCOMPR. 0.75 4.3 3344 9.57 1.40 6.06 41.92 10.16 264 2235
APPROXIMATE WTAL SYSTEM CAPACiTY REQUIRE
208
925
45
970
87
Table 9.2-3. Standby mode heat loads
P1bar
TIK
HIJIG
SIJIG-K
Kbar
iDK
RDJIG
SOJIG-K
FLOWg/s
WADW
Wear
kW
REFRIG 4.0 4.00 10.21 3.07 0.77 3.95 30.65 8.86 138 2800 238
LIQUEF 4.0 4.00 10.21 3.07 1.05 305.0 1599. 31.57 25 178
20-KSYS 3.0 14.0 84.91 13.25 2.00 23.2 134.9 16.9 200 10000 208
TOTAL LOAD CAPACiTY REQUIRED 624
COLDCOMPR. 0.75 4.3 33.44 9.57 1.35 6.05 42.08 10.25 138 1191 27
APPROXIMATE 1UFAL SYSTEM CAPACITY REQUIRED 651
Table 9.2-4. Assist mode heatloads
P1 TI HI SI P0 10 R SO FLOW WAID Wcar
K f/C JIG-K bar K JIG JIG-K g/s W kW
REFRIG 4.0 4.00 10.18 3.07 0.77 3.95 30.65 8.86 264 5400 461
LIQUEF 4.0 4.00 10.18 3.07 1.05 305.0 1599. 31.57 54 384
20-K SYS 3.0 14.0 84.91 13.25 2.00 23.2 134.9 16.9 200 10000 208
1UTAL LOAD CAPACITY REQUIRED 1053COLDCOMPR. 0.75 4.3 3344 9.57 1.40 6.06 41.92 10.16 264 2235 45
APPROXIMATE TOTAL SYSTEM CAPACITY REQUIRED 1098
88
10. UTILITY MODES AND FLOW DIAGRAMS
The modes of operationfor thecollider andthe highenergyboosterare definedby different
states. Such states are determinedby steadytemperatures,pressures,or othermeasuredparanieters,andby processes,which are therequirediransientsto changethe conditionsof
the collider to a new status. The logic diagramfor the different statesand processes
correspondingto the utility modesand otheroperatingmodesis shownin Figure 9.1-1.
Thefollowing is a listing of theutility modesof operation.
a. Warm gascirculationcleanup
b. Cooldown of sector
1. 300Kto8OK
2. 8OKto2OK
3. 2OKto5Kandfil
c. Magnet condilioning
d. Emptyingliquid heliuminventoryhandling
e. Warmupof sector
f. Magnetrepair
1. Stringemptying
2. Section isolation
3. Sectionwarmup
4. Sectioncooldownaftermagnetrepair
5. String fillup.
10.1 SECTOR CLEANUP
initial commissioningof the collider requiresthe circWation of clean warm helium gasthrough themagnetstringsandassociatedequipmentto removecontaminants,particularlymoisture and residual gasesin the windings and piping. The 20K compressorwith
appropriatesuctionpressure2 to 4 barandoutlet atthesystemdesignpressureto provide200-400g/s of 300K helium flow is usedfor cleanup. The flow is routedthroughthehigh pressureside of coldbox heat exchangersHX-1A and HX-1B, and throughthe80Kbed. From there the flow is bypassed throughV-1351 to the mediumpressurecircuit of
HX-1A. The streamis warmedto room temperatureand is dischargedat high pressure
through valve V-i 362 to thecooldownsupply line. Thewarm clean gas is suppliedto themagnetsiring and to the varioushelium flow loops through the cooldownsupply line. Thereturn flow is routeddirectly to 20K compressor suction. Molecular sieveadsorberbeds
89
in the compressorsuctionline removemoistureandcontaminants.Thedryer bed shouldbe sizedfor operationat theseflow andpressureconditions.
Initial Status
The cleanupprocessis performedprior to cooldownof thecollider. The whole systemiswarm, andthe linesare full of dry air. Beforethewarm circulation processis initiated thesystemis purged,evacuated,andchargedwith helium.
RcfrigerationPlant Operation
The 20K compressoris usedto provide200 to 400 Ws of 300K helium flow for cleanup,operatingat appropriatesuctionpressure2-4bar nominal and at the systemdischarge
pressure.The helium flows through the high pressureside of coidhox heatexchangersHX-1A and HX-1B, and through the 80K bed, and is bypassedto the mediumpressurecircuit of HX-1A via V-1351at theoperatingpressurefor warmupto room temperature.The high pressure300K helium is routedthroughvalvesV-1362, V-1462, and V-1506tothe main supplysingle-phasemain feed line to themagnetstrings. Thelow temperaturecoldboxis notoperated. Theboil-off from the dewargoesto the first stagecompressor.Ifnecessary,thecompressorsmay be operatedto processthis gas.
Thereare severalloops to be cleaned: themagnetstring, the single-phasereturn,thegashelium return, the 20 K lines, thehelium recoolers,thepower leads,etc. Thereturnflow hasseveralroutes:
a. The return flow is directed through the warm return header,throughcooldownvalves V-OO1; Figure 10.1-1 showsthe circulation processofthe magnetstrings and cm-rent leads,andreturnsto the dehydrationskidthroughvalveV-1324.
b. Thereturn flow is directedthroughtheOHe return, throughrecoolervalvesV-003; Figure 10.1-2 shows the cleanupprocessof the.magnetstring,single-phasereturn line, helium recoolers,and vapor return line, andreturnsto thedehydrationskid via valvesV-1421 andV-1323.
c. Thereturnflow is directedthroughthe20K feed and return lines, throughthequenchrelief valvesV-002 located in thespoolpiecesFigure 10.1-3showsthecleanupprocessof themagnetstring andthe single-phasereturnline, andreturnsto thedehydrationskid via valvesV-141 1 andV-1323.
d. The return flow is returnedthroughthe single-phasereturn line and viavalve V-1507 to thecompressorFig. 10.1-4.
Flows andoperation
A maximumflow rate of 100 g/s per string is availablefor cleanup, flow resistancelimitsthe flow through themagnetstring to a maximumof 40 gA The flow ratethrough thesystemvaries,dependingon thecleanuproutes.
90
Systemfinal status
Thestatusof the systemafter warm circulation is "WARM CLEAN." Thecold lines and
passagesare at 300K, and the quenchvalves, cooldown valves, and recooler controlvalvesare closed. The systemis clean and readyfor insulatingvacuumpumpdownandreadyfor cooldown.
Processtime
The entirevolume in the sectorhasto be circulatedatleastfive times. Thevolumesof the
piping and magnetflow channelsare listed in Tables6.1-1 and 6.1-2. The minumum
cleauptime is approximately20 minutesperioop.
10.2 SECTOR COOLDOWN
Cooldown of themagnetstrings is carried out in variousphases.Before any cooldownprocessesare initiated, the insulatingvacuumspaceand the beamtubemustbe pumped
down to the appropriatelevel of 1.3 x 10-2 Pa. The 80K liquid nitrogen shield lines are
cooleddownbeforeinitiation of helium cooldownof the magnets.The helium refrigerationsystemis designedfor a nominal supply of 400gls of
helium flow to themagnetstring for cooldownfrom 300K to 80 K. Thesupply pressures
andtemperaturesin variousphasesof cooldownare given in Table 10.2-1. Thesystemis
designedto enablethecontrol ofthecooldownfeed flow temperatureby mixing thewarm
andcold helium suppliesV-1362andV-1363. Someor all of theexpandersmaybe used
in various cooldown phases. During successivecooldown phases,the return flow isvalvedinto therefrigeratorreturn side atvarious temperatures.Thegoal is to controlthecooldownprocessof the different partsof the cryostatto minimize cooldown time andcooldowncost,andto preventexcessivethermalstresses.
Table 10.2-1. Cooldown conditions
Startingtemp
cold mass
Endingtemp
cold mass
Supplypressuz
lxv
ReturnPressure
hr
Supplyflowmte
g/s
Coolingcapacity
k W
Wavespeedrn/hr
Cooldownfime
Sectorinventory
kg
3cXK 80K 16 4 400 450 8.2 22.0 83
80K 20K 16 1.2 140 50 15.8 11.4 330
20K 5K 4 1.2 5OO >12* 36O O.5 22OOO
* With liquid consumptionfrom dewar.
The string cooldown processmay be startedafter the insulating vacuum has beensuccessfullypumpeddown a software interlock will inhibit the cooldown start-up ifvacuumconditionsare inadequate.
91
The cooldown of a string is performedin threemajor stepsfollowing cooldown ofthe80K shieldfrom 300K to 80K.
Step 1: Cooldown from 300K to 80K
Step 2: Cooldown from 80K to 20K
Step 3: Cooldown from 20K to 5K and fill
The cooldown of the 80 K shieldmay be performedsimultaneouslywith step1. If an
upsetoccursduring the first step of cooldown contaminationmay be released. The
expandersare not operatedbecausetheymay be damageddueto releaseof contamination
during an upsetcondition:
During eachof thestepsthe flows of thecryogensatdifferent temperaturesare routed
in different ways. Therewill be softwareinterlocks to preventdisorderin thecooldown
process.
Sector cooldown to 80K
Initial status
Collider initial statusis "WARM STANDBY." Thecollider equipmentis warm arid clean,
and the insulatingvacuumvesselis at a pressurelower than 1.3 x 10-2Pa.
Refrigerationplantoperation
A heliumflow rateof 400g/s at 80K is suppliedto themagnetstrings, 100g/s per string.
Liquid nitrogenfrom storageis suppliedto the80K shields,64 Vs per string for a total
flow rateof 256 g/s. Therequiredcapacityfor cooling the 400 Ws warm helium to 80K
is achievedby boiling 1125g/s of liquid nitrogen. The refrigerationplant requiresa
continuoussupply of 1125 g/s of liquid nitrogenfor thehelium systemand256g/sfor the
80K shield for a total of 4,972 kg/houror 119 tons/day 6 trucks/day.Only thewarm coldboxsystemis operatingduring sectorcooldownto 80K. Liquid
nitrogen is vaporizedand warmedup to 300 K by heatexchangewith thehelium streamcoming from thecompressorsystem. During cooldownfrom 300K to 80 K the pressuredrop is asmuch as 10 bar. Therefrigerationsystemis capableof supplying80 K helium at16 bar. Undernormaloperationthewarm returnheaderis pressurizedto 4 bar, and only
the 20 K compressoris requiredto providethe400 g/s ofcirculation needed. If the returnheadercannotbe pressurizedto 4bar, the systemmust be operatedat lower flow ratestopreventdamageto thedehydrationbed. Theflow exiting the 80K adsorberbedsis routedto thecooldown supply line throughV-1363 and to the single-phasemain feed line viacrossovervalve V-1462. Theflow bypassesthesurfaceprecoolerthroughvalve V-1508.If the precooler is still warm, it should be cooledto 80K by openingvalve V-i 514, withthe waim gasvented through V-1512. A flow of 100 Ws is directedto eachmagnetstring.
92
Flows and operation
Thefirst stepis to cool down the 20 K shield. This cooldownneedsto be carriedout at a
controlledrateto preventexcessivethermal stresseson theshield.The 20 K shield can becooledindependentlyto 80 K using eitherof the following two methods:
a. Usinghelium flows throughcrossovervalve V-1461, V-1508, and controlvalveV-3014.
b. While the quenchvalves are openedthe 20K shield may be cooledsimultaneouslyby 80 K helium flow from the single-phasefeed throughcontrol valve V-3001. The flow rateis controlled by V-3001 to preventexceesthermalstresseson the shield during thecooldown. Oncethe20 Kshieldis cold, the flow rate to the string is increasedto 100 g/s.
Thereare alsotwo possibleways to cool down the magnetstring.
a. Thefirst methodFig. 10.2-1is to cool down themagnetsin parallel bysupplying 80 K helium throughthe20 K lines asfollows: Everyhalf-cellhasa quenchvalve and every full cell a cooldown valve. During thisprocesseveryotherquenchvalveandeverycooldownvalvearekeptopen.The 80 K helium supplied to the 20 K shield lines flows through thequenchvalvesto themagnethalf-cell andthenthroughthe cooldownvalvesto the 300K warm returnheader.
b. The secondmethod Fig. 10.2-2 is to simultaneouslysupply the 80 Khelium at one end of the string to both the single-phasefeed and single-phasereturn lines.Thewarm flow is returnedthrough thecooldownvalvesto thewarm return header. Eachof therecoolers’valvesV-003 is keptopen,andthecooldownvalvesV-OO1 arealsoopened.A cooldownwavedevelopsandtravels alongthe string. Eachcooldownvalveis closedasthecooldownwaveprogressesalongthestring.
A small paTtof theflow may be diveneddirectly to the warm headerthroughthe
currentleadsandbypassleads.At this point, althoughall thecooldownvalvesarenow closed,partsof the system
may still be warm. The 80 K helium is thensuppliedthrough the single-phasefeed and
returnedat theend of the string through the single-phasereturnline. Therecoolervalvesarekeptopen. This flow schemeis maintaineduntil theremainingpartsof thesystemare
cooledto 80K.The cooldownsupply temperaturecan be controlled by mixing warm gas through
V-1351 and V-1362with cold gassuppliedfrom V-1363.
Systemfinal status
The statusof thesystemafter cooldown to 80K is "COLDMASS AT 80K." The 80 Kshield is refrigeratedby nitrogen at a nominal flow rate. Cooldown valves V-OO1,quenchvalvesV-002 andrecoolervalvesV-003 areclosed. All partsof thestring areat
93
80 K and at pressuresof 0.1 to 0.2 MPa, and the 20K shield is also at 80K. Valves
V-3004 and V-3014 are closed. No flow is requiredin the cold mass. The helium
inventoryin thecollider sectoris about83 kg.
Processtime
Thecooldownprocessfrom 300 Km 80K will takeapproximately22 days.
Sector coolciown to 20K
Initial status
Collider initial statusis "COOLDOWN AT 80." The80K shield, 20K shield and thecold
massof the four stringsareat80K. Liquid nitrogenflows in the80K lines.
Rqfrigerationplantoperation
The cooldown processfrom 80 K to 20 K is designedto be performed in one step
Fig. 10.2-3. However, if necessary,this cooldownmay be accomplishedin multiple
stepsby mixing 20 K helium with warmergas. High pressure15 K-20 K gasfrom V
1443 is fed throughthecooldown supply line to the main single-phasefeed line. The
magnetstring, the 20 K shield, the 4K return line, and the OHe return line arecooled
from 80 K to 20K during this process.
For 80K to 20K cooldowntheavailablecooling capacityis approximately50kW,
definedby theexpandercapacity. Helium at approximately15K at high pressurecan be
suppliedat the rateof 140 g from the high pressuretap throughvalve V-1443, located
below thethird expander.Thecold flow is suppliedto the single-phasefeedline through
valvesV-1462 and V-1501, to V-3001 and V-301 1 and to the single-phasereturn line
throughvalvesV-1503andV-3102 to valvesV-3002 and V-3012.
Thereturnflow to theplant is a combinationof theflows throughthequenchvalves,
through the 20K lines to valvesV- 1508, V-i 510, and V- 1411, and throughtherecoolers
and the vaporreturn line, throughV-3103, V-3104, and V-1421, This flow is returned
throughvalveV-i 321 to thefirst stagecompressors.
At theend of this processthenominal 20 K flow is established.
Flowsand operation
Nitrogen flows maintain the 80K shield at the nominal shield temperaturerange. The
availablehelium flow rateis about 140g/s. In the collider this flow is divided into four
streamsof 35 g/s each,andin theHEB this flow is divided into two streamsof 70 Ws each.Theflow ratesandpressurerangesfor this cooldownphasearegiven in Table 10.2-1.
Systemfinal status
The statusof thesystemaftercooldownto 20 K is "SYSTEM AT 20K." The 80K and20 K thermalshieldsarekeptat their nominal temperaturerangeby nitrogenandheliumflows. All helium valvesin the string-i.e., thecooldown V-i, the quenchV-2, the
94
recoolerlevel V-3 andleadcooling V-4 valvesare closed. No flow is necessaryin the
cold mass. Thehelium inventory in the collider sectoris approximately330kg.
Processtimes
Table 10.2-1 givestheestimatedcooldowntime andwave speedfor the variouscooldown
phases.
Sector cooldown to 5K and fill
initial status
Collider initial statusis "SYSTEM AT 20." The 80K shield and 20K shield are at the
nominal temperatureranges. Liquid nitrogenflows in the 80K lines, and 20 K helium
flows in the 20 K shieldlines. Thecold masstemperatureis in therangeof 20-25K.
Refrigerationplantoperation
Before startingthis processthe helium dewaris filled with liquid deliveredfrom external
sources.This is the final stageof cooldown,during which themagnetstring is cooledto4-5 K and filled. The refrigeratorsupplies 4 bar, 4.5 K flow through V-1502 and
throughthe single-phasefeed lines to V-3001 and V-301 I Fig. 10.2-4. Flow can besupplieddirectlyfrom thedewarvia valve V-1504Fig.1O.2-5or, if a pumpis available,flow can be suppliedto thesurfaceprecoolerthroughvalve V-1515Fig.1O.2-6. As thecooldownwavetravelsthrough thestring, inventoryaccumulatesbehindthe wave. As aresultthe returningflow rateis much lower thanthe supply flow rate3-5% of the supply
flow.During the final cooldown,therefrigeratorwill experiencean imbalancein flows and
will operatemainly in liquefactionmode. The coldboxflows arebalancedby additionalflow from thedewar; this flow is evaporatedin theprecooler. The20K vaporreturning
from thetunnelbypassestheheatexchangerV-3102 andis divertedthroughV-1507andreturnedto the coldboxheatexchangerstackvia V-1422. It is preferredthat the finalcooldownand fill not be madedirectly from thedewar,as this would resultin two-phaseflow to thestrings.
Flowsandoperation
Theflow ratesin the80K and 20 K shieldsarekeptat their nominal rates. About 500 Wsof 4.5 K, 4 bar helium from theprecoolervalveV-1502 is suppliedto thesingle-phasemain feedsupply line.
Systemfinal status
Collider statusafter cooldownto liquid temperaturesis "COLOMASS AT 4K." and thesystemis pressurizedto 3-4bar. The 20 K and 80 K shieldarerunning normally. About22000kg of helium inventory is presentin themagnetstrings whenthecooldownand fillprocessis completed.
95
Processtimes
At 500g/s theprocesstakesapproximately12-15hoursto complete.
Temperaturesettingandcontrol.
After cooldownto 4 K-5 K therecoolersare filled and their level control loops may be
activated. At this point thecold compressoris startedand the vaporreturnline pressuresare loweredto their nominalvalues. After all the operatingparametershavesettledto theirnominal values-in particular, when the operating temperaturesreach those inFigures7.3-1 or 7.3-2-thestatusof the ring is changedto "STANDBY COLD."
10.3 MAGNET CONDITIONING
Conditioning involves operatingthe string of magnetsat a reducedtemperatureandcycling
up the currentto a point abovethe nominaloperatingcurrentof thering. A separatecoldcompressorwill be mountedin serieswith theexisting cold compressoronto thehelium
cold compressorbox. This arrangementwill allow the temperatureof thehelium suppliedto any one of the four strings of magnetsto be reducedto 3.5K. One string will beconditionedat a time, while theother stringsarekept cold at 20K with only the 20 K
shield active or, if necessary,near5K if a neighboringsectorrefrigeratoris availabletohelp maintain the string temperature. The SRS will have sufficient capacityto handleconditioningof onestring at a time.
initial status
The refrigerationsystemsuppliesthe nominal flow ratesto the rings at the nominal 4 K
temperatureand4 bar pressure.Thehelium recoolingschemeis activated. The heatloadto the ring is only static no beam,no high current.
Systemoperaiion
The surfacerefrigerationsystemis operating in its nominal mode. The secondcoldcompressorlocated in the tunnel is operatedin serieswith the first cold compressortolower thevaporpressurein onestring.
Flows and operation
Thevaporpressureis loweredto 0.4bar andonly onestring is refrigerated.
System final status
The systemis backto nominal operatingconditions,"STANDBY COLD."
Processtimes
Thetimefor magnetconditioningwill vary, dependingon requirements.
96
10.4 SECTOR/STRING EMPTYING
Emptying the systemis required for two main purposes:
a. Warmupcycle for thedesorptioriof gasfrom the beam tube.
b. Warmup for maintenance.
The liquid inventory of the magnetsis to be transferredto the storagedewarson the
surface. High pressure20 K gas from the shield is allowed into one end of a magnetstring, pushing liquid out. The emptying processis controlled in order to maintainsupercriticalpressureduring this procedure.
Initial status:
Collider initial statusis "STANDBY COLD." Strings arecold at 4K and no flow in the
cold mass. The20 K shield and 80K shieldarerunning.
Refrigerationplantoperalion
Thelower temperatureloops including expandersmay be deactivated.The 20 K helium
ioop is operatingnominally.
Flowsand operation
By openingthe quenchvalvesin the magnetstring and lowering thepressurein the4K
lines, the 20 K helium is allowedinto themagnetcold masschannels.The supercritical4 K helium is pushedoutof themagnetstrings, displacedby the20K helium gas.
System final status
After emptying,thetemperaturein the magnetring is allowedto go up to 20K.
Process times
At a flow rate of 100 g/s in each string,it will takeapproximately12-15hoursto emptyallfour strings. About 22000kg of helium is removedfrom the sectorto the surfacedewars.
This emptyingprocessfor gasdesorptionis performedat regularintervals.
10.5 SECTOR WARMUP
For warmupto 300K, warm clean high pressuregasfrom the refrigeratoris suppliedtothe 4K supply line throughthecooldownsupply line Fig. 10.5-1. Magnetstressesaremanagedwith thesupply temperatureofthe warmupgascontrolledby mixing warm and80 K gas. One or more strings may be warmedup simultaneouslywhile theremainingstrings are kept cool by helium flow, either from the local refrigeratoror from theneighboringplants.
97
Initial status
Collider initial statusis "SYSTEM AT 20 K." Thermalshieldsareat nominal temperaturesand nominal flow rates. Thecold massis at 20K andat low pressure1-2bar.
Refrigerationplant operation
The string can be warmed up by supplyingwarm gasfrom therefrigerator. This requiresthediscontinuationof thecooling loops to theotherthreestrings. While one stringis beingwarmed the other strings are keptcold. The isolation valves betweensectorsare opened,allowing the other neighboringsectorsto provide cooling for theremainingstrings. Thesingle-phase feed and return lines areused in these warmup loops.
Thesupply temperatureof theflow for sectorwarmupcan be variedby mixing warmand cold 80 K gasif a smallertemperaturegradientmust be maintainedalong themagnets.
Warmpure high pressuregasis suppliedthroughcontrolvalve V-1362and via crossovervalve V-1462 into thesingle-phasemain feed line. Thesurfaceprecooleris bypassedbyopening bypassvalve V-i 508 and closing V-i 501 and V-I 502. An alternativeis topressurizethe warm returnheaderto at least2 bar in order to supply warm gas; in thiscase,thecold flow is returnedthrough the20 K linesvia thequenchvalves. This allows aparallelwarmupof the shorterlengthsof the string,decreasingthe warmuptime required.This also "softens"the warmup rate, thus reducingthe stressesin the magnetsduringwarmup seeFigure 10.5-2.
For long-term storageof the systemat nitrogen temperaturesthe 80K shieldsareoperatedatnominalconditionsandthe20K and 4 K flows may be disconnected.
Flows andoperation
Flow resistance limits the warm flow that can be circulated though the string. Thewarmupratewill vary dependingon theroutesusedfor thesupply andreturnflows. If alltheflow is suppliedthroughthesingle-phasefeed andexits alongthe20K line throughthequenchvalves, flow ratesfor an entire sectorwill vary from over 400 g/s at thestart ofthewarmupphaseto 40 g/s whenthewarmupwavereachestheendof the sector.
Excessinventoryfrom therings is storedon thesurfacein thegas tanks.
System final status
Thewarmupprocesscan be stoppedat different temperatureslevels; the temperaturelevelwill definethestatusof the system.
Process time
The time requiredto warm up an entiresectorvariesdepending on the routes usedduringwarmup and how much the warmup rateneedsto be controlled to managemechanicalstressesin themagnets.Warmuptakesabout22 daysif only 400g/s is used. Theparallelwarmupmethodallows for thefastestwarmupand shouldcutthe time by morethan half.
98
10.6 SECTION REPAIR
Therepairof a componentin a sectionrequiresthe isolationof the sectionfrom the rest ofthe ring. The flows throughthesectionmust be reroutedto keepthe rest of thesectorcold.To removeor repair a specific component,such as a magnetor a spool, requires thebreakingof thevacuumin a half-cell; this is doneat room temperature.A sectionin thecolliderrangesbetween360m to 1350 m and in the HEB from 1220 m to 1480m. SeeTables2.1-2 and2.2-2. Thesectionis thesmallestpart of thering that can be isolatedand
warmedup asa unit.
String emptying
For repairof a specific section,the entire string is emptied. This is doneby the same
proceduredescribedin Section 10.4.
Section isolation
All thecryogeniclines aredepressurizedto one atmosphere.Thecryogenicflows in the
neighboringsectionsarereconfiguredto keeptherestof thesystemcold-in particular,to
keepthenitrogenin the80K linesrunning. SeeFigure 10.6-1.
Section warmup Figures 10.6-2, 10.6-3, and 10.6-4
Thewarmupof a single sectionwithout warmupof theremainderof the strings, requiresan externalwarm helium circulation. Therearethreeoptionsfor warmupof a section.
a. Warmupusing low pressurehelium from the warm helium returnheaderrequiresa blower and heaters. The warmupratewill be limited by theblower’s head production. Warm gas from the warm return headeriscompressedby a blower, and the flow is split to the magnetcold masschannels,thesingle-phase.retumline, andtheOHereturnline. Thequench-valvescan be openedto allow flow into the20K line. Theflow exiting theotherend of thesectioncango to a commonheaderandbe heatedbeforeitis returnedto the warm return header. if the warm return headercan bepressurizedseebelow no blower will be requiredfor warmup.
b. Warmupwithout a blower, using helium from the 20 K line, requiresahelium streamfrom therefrigerationloop. Someflow from the20 K loopcan be usedfor this wannupprocess.The supply pressureis higherin thiscaseanda higher flow ratecan be achieved,and in turn a higher warmupratecan be achieved. The 20K flow is heatedanddeliveredto the single-phasesupply line and also deliveredto the single-phasereturn line. Therecooler valves areopenedto allow flow into the gas return line. Thequenchvalvecan be openedto allow flow into the20 K line. The cold gasexits at theend of the sectionand is collectedinto a commonheader,andheatedbeforeit is sentto the warmreturn header.
99
c. Warmupwithout a blower can alsobe accomplishedusing helium from thepressurizedwarm returnheader.Warmgasfrom the warm returnheaderissuppliedinto oneend of the sectionvia the cooldown valves. Thecold gasexits theotherend of the sectionthrough a quenchvalve into the20 K line.To preventdamageto the shields,care should be takentoward the end ofthe warmupsequenceto preventwarm gasentering the 20 K shield at anuncontrolledrate.
Section cleanup
To getcleangasfor removingcontaminationafterrepairs,someof the 20 K flow mustbeused. The samearrangementusedin b, above,for warmupof thesectioncan be usedforcleanup. Another option is to supply high purity helium from portablepressurizedgascylinders.
Section cooldown after magnet repair
The 80 K shield is cooleddown by allowing nitrogen into the section. Then the 20 Kshield is cooled by a controlledand moderate20 K flow. The cold mass is cooledbyopeningthequenchvalvesand allowing the20 K flow into the cold mass,and the warmgas is vented through the cooldown valves to the warm return header. When thetemperatureof the warm gasdropsbelow a setpointvalue thecooldownvalves and thequenchvalvesare closed. SeeFigure 10.6-5
Section cooldown to 5K and fillup
The entirestring mustbe cooleddown to 5 Kand filled oncetherepairedsectionis cooledto 20 K Forthis purpose,the sameprocessis usedasdefinedin Section10.2.
100
FIGURE 10.1-1 WARM GAS CIRCULATION: MAGNET STRINGS, WARM RETURN HEADER, CURRENT LEADS
V-b7 *VIlM D V-la"
frIIIl I
E
%I LEJ
I.’-’’
372
v-"o
v.j,24
av-lw
300K - 80KCOLD OOX
flfl
v-nt’
lIP 20K LP1_.................-I 14Q4
I_______________
V4422
II1
- j-%
Vl4l4 I- I
- I
-Dc-- CR IV02 I
Li
r:ii HP
V.1442 ‘ II CS i_v_s p
i___V.1443
I v-I.,
V 531 V.1532
L
_______
----W1M4 V ‘50
v-Jill
L
SURFACE
TUNNEL
r;r -,-I
80K - 4K COLD BOX V114
v-un
V-1432 -*4v-i.,, V1431 J4X3
V1421
V-lilt
--
L -
COLD COIPRESSOR BOX
v-iw v-flu
-I5jl
* V
SURFACE DISTRIBUTION BOX C
*Iv-31g3
______________________I
-I
I1
fTWW IflbCR
v-o
IsS
1
_____________
- e "k LEAD
- -
____
_! !LS I
____________
--
SURFACE
TuNNEL
- -
r--4Si 1I
‘--4
a
L4
C 1 F 1L
V11
11iF iIIr44TJ_iI J tL L 3
1---TUNNEL
I DISTRIBUTION
box -
I -! U -J U rI vnvI I I I I I I
II-v -vii I I I I8’
-- N: 1’It 4I1f1pfJLD{WI5 L__J.et1....__J fftcrR L CLER L_
- 4
I I Iwru L J - -
H
41 I
HflTV iILL.. Hi tE Ii
flILI
J ‘4---#’LEfl T Ic.I.c IC va .uu RtTjt ICAbCw
I! JLia
a
v-I7
- F
V1%2
r V1%2 L!j_iGN2 t3" lu-IA -
S
300K-80K
COLD BOXv-In’
-0-s--
V1321
V1321Dl
-- I
-J
1HP lIP 20K LPI v-itI I I_______
WI.IZ/
______
Ix I I- V1443
7?L____J 80K - 4K COLD BOX :: k4I AI LI 1 1
_____
Iv-I4i Q* V142 -
__________
V11R -
_____________________________________
-
I. -
V
v-I."
-tV1412
--V1411
L
4-rr iI IJx
____
531 * Vt52
______:
I t-;:t----- V_l54l
I
__________
L_IIDI
L2_..COLD COMPRESSOR BOX
rv-izoe v-wj
-I
CR
g I
C wm.n,. AMI
v-I,"
SURFACE DISTRIBUTION OX
-Ill
V
c
v-3N4
V3t15
-I
I v-Jo,
-I
-;- .-I’
- -
S
ao
LEADnIpc
.1. itrV4 X X v-i
t’!°’ itIi -
‘IV3IaU i.
1k
SURFACE
TUNNL
EcTED
r4I I I I - I I I rii v-JL A IL J iii
a
irI.JIF_ iiri
v-ala
i *1I -r rI vavt I I I I II 11V3 t-v,I I I I I
______
I .4r°4’if.1f
s"-
____________ _________ _________ __________
-Va- L___J &c L___J ER L_ __J RZCCR
____
I
____ ____ ____
v-,a%I r
1i$ 1iFII CR1 Rtmt,
v-’°Il
wr’n L L‘I *1- 1 -; *‘ II -
* ffa1l v2’*I siITUNKEL N, I
III II ‘I H
___________________
jDIST2lJTIOH wrev’11 -f 1 11 Ii 1v-wa
S SI BOXL. LJ
LtJF-l
LEADT0 v Ica .t11 *CaR
FIGURE 10.1-2 WARM CAS CIRCULATION: MACNET STRINGS, SINGLE PHASE RETURN, RECOOLERS, GRE RETURN LINE
TUNNELDISTRIBUTION
BOX
LEAbon-ncI IC
‘v-. 2’-’
I v- I
FIGURE 10.1-3 WARM GAS CIRCUI.ATION: MAGNET STRING, 20K LINES
ii v-IISI
Ov-
V3U LSMLJc,
V-lU’
-1N’-’’
- .0-lu300K-BDI
FCOW BOX
V1322
V1M1
1hF’ 20K LPI v-l.a.
VHfl
B- I
* j-I
V-1414 I- I- I
-Dcl-- CR I
Vtl2 I
SOK - 4K COLD BOX v-io
V-iI
v-i432
__ __
V1452 V-Nil
H- 372
aJL -r
HP_,..
I
__
cs
_____
V-i443
C
IV-u43I Q
53! 4 V-1332 **
______
I
I v-h4 IA
COLb COUPRCSSOR BOX
::-;-j:
L
SURFACEr -
TUNNEL I
L
rv-lw v.
v-I,"
SURtACE DISTRIBUTION BOX L 2Ikfl
-J
V Wk*dEThfl
IT I I
II+IV-3.a3
Di* ia
I
*1 -4
1
-4
-Dlv-,-S
at S
SURFACE
TUHI4EL
mm IIrI
I IL
ULING
IiIi
z
- S
1 V
;i :v.sti4 -l
I S I -- -lL Y-W J
0L0C4 I I rV.tVI I I I I
Il-fl 1V11 I I IV I 4’
_____
‘-
_____ ____ ____ ____
I L - - - J’.rrrar. 1 - L__JI v-_I
V-MISI r----. r----i
D41 1L0lf 1&1 11’
Y$tI
Li
1
v-i4 I I I I I I I II I_____ I I - I I
__tria.TjIY, "‘I
zmar.ftj jlI’ IM,Ii iI_j 4v2$
1 II II II II II VfliI .1
L - 4--t ‘----fcoT T T TC-IwG IC LII PET,i CAK1
v-ta I-----
HP MP2OKLPI_
I V-144 I J‘1’
_________
V-i14? I
V-1443 __1 80K - 4K COLD BOX ;;:; i-I
____
I L V-II5 V-1431 JD<
_______
i-’-’
___
v-l2 - -
-I
CR
I
:iI
--4
v-a!
:i 1H4 4v-i,
1 Iv.tvtl I I I I
__________
p I IIV3 I-v4I I I r-
- N:1r h
L___J cn L__JVXfl L___J
, v-iIi r
1
______ ______ ______
1F 4’FII
t’
.clr..nrn * i_ * IiIi - - ‘r-i iv-ctttT
iII IL ii II jJ I
FIGURE 10.1-4 WARM GAS CIRCULATION: MAGHT STRINGS, SINGLE PHASE RETURN UNE
V rn.,
V I2
HYDR-3
V-1324
r
r
Lt
EEEEEE1:fiV-nOS
-
300K
COLDVfl!i
- 80KBox
-J VI2,
--I
I J
V1114
-N--t-¼-V-t4
v-Mav-w’i
t
_____
I’s’
-
___
I
_______________
L_i_tj_ - I
L-coio C0TM:::: ::
__________ ____
flEC&
- SURFACE DISTRIBUTION BOX
IVI5t V-i5
1il
V
[
-4
2.
TT1I1P-DC
SUR FACt
TUNNEL I
I.-,
IIIx I
LEAD
IT--tv,’_
SURFACE
TUNNEL
il
‘--4
V-34Il I7-;,
I r -II I I
!irti
- -
TuNsaDISTRIBUTIONBOX
fl! W’LJT iJLJT JPv-z L
r flMW es*n* Iot
-cc-
L.LEADCINC TO - *flL
t --
V21 L.._...
n TTa r-,;1- -
L::i d!i ‘jI
HPMP 2OKLPL... 1I v-i.,i I
I V-i42’___ I
-r zifl
______
-tI I II - _- I !-p3----..---- V-142 I
I V-HI BOX - 4K COLD BOX Vi434V 1422
1I
_____
V1477 I
I g
_____
V-HX$< S
I L v-i, VII3Ij-P -*4*."- I
-I
-ll3y V149 V-MlII
I a I IL - -- J
- --- ---Iv-s, 2 V-t3Z I -IlI I
4N±
SURFACE DISTRIBUI1Ot1
---ISURFACE
COW COMPRESSOR BOX ,
III" I
---.
____
I TUNNELI DISTRIBUTIONpeoxL .4
mx
suprAcE
TUNHa
- 1 *i ----iLAO r W WUM
PG prIus fAoo -I ING
I
-a----4c f[--t} :9
___
¶ VilNr
_____________ ______________ _____ _________
F>1 r-l
I
_____________I
I/
____
--J
_______ _____ _____ __ ___
1I II I
_______
I II r--D<- * :I I
I I I I I I I I
- SapJ. II
-: L *‘-" -J nrirnit_..._J . L_J -- rt-- _ v-* r --
Ina4i$.
4IW41
_____
IR 1 SRII,I I I
I I I I I I I I ITIa SV I 41 ZI i
____
- * Tta,Ii fli iv-rr’ I-‘ I- N-
I II Ii 11 II II II II III .JI I. I- *
LCAD
I........4,J L..._.1 L...-1J L.._...1.J VWa L_._
CflIc t$auI.. .CL *t1,. *C*IC
FIGURE 10.2-I SECTOR COOLDOWN 300K 10 80K
-I
V
‘-‘IT,
I V-15M v-I.3 V-l5I2 V-Thu
I___L
-
Vi362 v-au
I Vflfl -! Ia-IA
_____
-
Lit7 I!! E s:: ::± T:Ln: :::::::HP MP 20K LP1........
I V-Jill Ip____I I V.4423 Vl4I4
I CS L 1t3I I II - _ _._. v-ui
V-H43 80K - 4K COLD BOX v-" -NV14fl
I I v-I4I4lI
A v-,,91-t.lI
___
II L V-1453 V-1431
- -a-V-I4 OX V-119 I V-L4ii
Li! 4V I I
_____
r .I 1Vt5II
I I I ‘ I PRZCCI I I------- v-iM £
A I I SURFACE DISTRIBUTION DX -‘? V-1117 VLJ_j_44__ --
_________
I V15& Vi6
___ _____________
S
_________________________________________________________________
Lrç;J i -; I -t 1 -----1 Sg-- 1V4
I I - r " ‘1L I I t - h
_____
rtL--4I V2j I I Ii
-Ti1I I *1 f3 DC-
I :: L:±k:k1_D
--ML 4-1-D H-. ucnt, TT lx1GfI ir s
I I I I I I I I
______I ________________________________ ____
-- :::t’ ‘ .-!
____
[8UflON
::_3 LJ.* L} .‘JL JLEADT I ICING TO V PCRM IrTN cat
FIGURE 10.2-2 SECTOR COOLDUWN 300K TO 80K
v-Itt,
FIGURE 10.2-3 SECTOR COOIDOWN 80K TO 20K
v-ia’?
G112v13’I 1*-li
tv-I,
r
v-Ifl
0
c?Lr::I CS
COLD BOX
HP
v-I,"
V-1141
- IV+42 /fl
Y-1443
-
Iv-lw
v-It
UP 20K LPI V-1414
I v-1423
*4-1421
00K - 4K COLD DOX v-i.,,
I
__________
V1433 1t7<VH32 I$
I L V-1153
I I -I
v-I1. V-I42v-Ma
____________________
--
___________________________________________
-
V-i4Il
-¼-
V442
v-mi
,1511
v- *
____
L
SURFACE
TUNNEL I g4-
-,IkDI
rV-llt V15N
53I V45320j
C
L
LT.21_..ft COLD COMPRESSOR BOX
-i-- . 4 *---- 1*0
*t7- "‘2
-1
CR
I
a I
---I
V WI
v-I,"
SURFACE DISTRIBWIOH BOX
V
V3II4t_
N
_
II v-aa
SURFACE
TUNNEL
rn
r--4
- I
‘-4
a
r1r-ir 11 r ii r 1I r -ijI Ii .11 L JI IL . I
V_2- -
a
‘r x
r
jJJIL44
ri t - r - ___i F
::
_____ _____ _____
*Elt I
________ _________ _________
r
4Et’F 1ZtJf LI
a -r4 I v-14
oI I.w urn
TUNNELDISIRIBLfflON
OCX
- L_J
I I
I MIA!! E1fl !IflJt*1
2
iii IL iiI- -J
ICAD 1ING To tK *C1u4
H
JAJ H*t*IL ii I[
L L
- _$-I
FIGURE 10.2-4 SECTOR COOLDOWN 20K 10 5K AND riLL
11
*0V-IOO2
V13Q
GN2V-fl7I
v-fl’,
V-IOO
L
=
-
NII300K - 80KCOLD BOXv-in,
vao
V1324
V-1122
V-i32
I V-M24III
I vt422
-SV-i4U
t
liP 2aKV-1411 I
- Iv_,,, j’ I
-_I
V-IIC
LPr - -
I CS
__________
80K - 4K COLD BOX VI434
I
_______
V03
I v-I43e I-*1
I L v-1153
V-I4Q -
4
-
-_-__- I
* j-I
V4I4 I- I- I-Dcl-.-- CR I
V1112 I
§ I
----I
V
V.401
v-IlIi
4li
v
v-nw I:1.
SURFACE DISTRIBUTIOtI Box
rVi5 VI6
___
I v-,iia
v:,5
c
-
I--
VZ5I
r w MaXM171W
LEAD
flN
-
531 Vi5R
______
II
A IV1SI4
I I
___________________
L_JtI.._ -
LX-SURFACE L.
;;;ELI,
____ _________
1107 I -
lflhliitiI I - - -Z t
- - *h! aI v-oeIJ
I
_____
I TUNNELI DISTRIBUTION 0* IraI 90XL
LEADCaING
SURFACE
TUNNEL
IF
‘--4-l F 1 r -i r
I - I I I !-!
IJI IN-"4tt41
I ‘V rI VALYCJ I I I I I I
II IIv3 -v.1 I I I IvI
- :v-s4
____ ____
"I L___J cac’t.._..J Lr, -
Lfl! 11
_____ _____ _____
pI IV-CI4 I
1
11
H
II
1
TO W SCjlSq UCTII tIXt
it[ ;‘a-i
Ji ft L Ji IL
n:j iv.4Vt$
L -
--i-_i-i
FIGURE 10.2-5 SECTOR FILL FROM DEWAR
r"NI-IA
Y-1fl4
Ia-ti
-* Ov-Iafl O V-I7iJ
cj_____
____ ___
1I LN2
________ _______
r- --D1- 300K - 80K Vi2i
V-i%3
912flCOWBOX -M-----------
___________
VlI
7 II -*1------"
L - L...
HP UP 20KI I
V14i4
____ ____
I I II - -fri I V1112I v-No C BOX - 4K COLD BOX V4422
IA v-1432k,<
,-.,, v-iiJ-c
__ i
.
iv_iI
SURFACE L
L
___
I_ta -
_________________________________________________
EftS
!
SURFACE
TUNNEL
a
i-rI
T1 1 1II I I
I.-I
L -rr1
_____ __________________________
IDI -I
_____________
Lfti
tflLiF
!1 n.tt
I I
I Im eI II
pI I
II
I TUNNEL -c- -DISTRIEUIIOW UI ‘L
L -‘LEAO T TcnhI
V-22 I
lNG
r - -fl
H
- paII - uIlI3"$__1I - I I
IIv_-I,
1
v_ti2
I I F I rIVSLVLI I I I I I II IkV3 I-v41 I I I I
HI1f 4I
LJ LJ- L - - - J’.tco1icp tv-and ‘
_______MI
r
-IV.II I
I Ir LJ
RECOOI.ER
*1 I
fl
.HIItI*1 t
-H
ID ‘LII *tTItj
yrt
r -
I CS
gL
v-ã43!
v-I4,IlI
SURFACE DISTRIBUTION BOX
r4
__ ____
a
_____
‘I
-4
a
LEflCLlNr
:niwry:e1 Jir1l
j wa":’!4
-
V-fl
80K - 4K COLD BOX
ii ILL - -
VJ4J
v-lot
I
- j-t
gV-lID
-11
1OX
V
I A111IE1W NAm
SURFACE
TUNNEL
I LEAD -VALvE + + Ct-DC
x’fti ,‘ s:IL4Ir L I1_. ] [ vi; -t
"4
vwjI r -! - I I I
- I VatYll I I I I I II II-V3 -v41 I I I I
__
I
__ __ __
Iaa L_JL__J’ -Va rcmERLR
Iv.II
0’2_KIUW
___________ ________
v-3iI ‘ r---n
__________
c1II
____ ____ ____
41
___ ___ ___
1*!D LI! .1 .1-; *
- -
$1I ______ r -- aI -
I ,..GinM ‘flUI TUNNEL
IDISIRIBUTION ..., yyj; I II I! I 1 ILL tIDOX
LEADCTLIP TO tat
i_ -;-
FIGURE 10.2-6 SECTOR FILL FROM DEWAR USING PUMP
- 80KCOLD BOX
IHP
20K LP1_.V_Nfl
V-140 CA:
v-i42
I v-1422V-i134
V 1414
V-1412
v_ic’
L
SUR FACt
TUNNEL
-,I ‘on IIx I
-
____ ___
LL.COLD COMPRESSOR BOX
VIZ
c
-
n
--
rIGURE bA-i SECTOR EMPTYING
V i7
-a---- *n-s.
v-i,.,
1A&
WiltV?I
L
rNI-I.
V.1324
av.u22 I
V
20K LPL_I v-...i 1-44---I I I V1423 V1414
I
__
I CS
________
I II - - I-v<--------- V-Mm
VI443 C 80K - 4K co sox V-Ufl
I I. V4fl3 Vll3’ j*<
I - v-MaV-i4Ip Q VI432 I VICL
I IL
aI
-
-I
CR
SURFACE
TUNNEL
l5U--
I PflCfl I -
SURThCE DISTRIBUTIaI BOX
-V-1543 v-iIu v-,
*1
IIIv-3113
: U
[V.
- V3111
II
V- - -- j -- LEAD
DunGI r.1. £WCPt
EflW*fl jf- -
____
II -tII*
L-1---
_____
SURFACE - - -
I COLD COWPflSSQR BOXTUHI4tLI. -
rr1101
L® L:I - s’_
----r-".fl.I.L
---®
_____
I j I
TUNNEL
I
_______________________ ______________
IBOXL
LEbCWLIIC
Lc- I iijIJ
I- ii------ I I Ii
v-4j
i-IL
-ii r- II I V112
_____
SL J_1
I --- I I t-t’
-l
I cast.. I I I I I Iv-sI I VAtyrl I I I I I I
______
II Il-fl IV4l I I I I
In-
PEC.CR__I LJ".tt.. Jv-I
- V..u ,
___
-
V Is I* :
-- 1 I
H
3
In -I I
I I I
Th - ,_ -Pc.
v-q lIII ,I Lvi4"" III I * I -I
II I 1 II 1 II II‘I - -ii .L ...jI i
lb V&SW ICLita *CTWI. ItA
I * Vt
L
-
J
V1362
FIGURE 10.4-2 STRING EMPTYING
300K - 80K
v-no COLD eaxV-If!
- 20K
V-114p I-- I
Vl442 I
A:
I ii I
V-lw
- J
CR
v-IO7 v-I9
SiVLTOIO
v-nfl
Ia-PA
H!11
Yi322
Lft::
I CSI
-I
V1414
--
-MV-I 412
Ii
____________________
I V-1123
I -
80K - 4K COLD BOX V-I44v141Z
I V-14B
V-l432 I-t’cJ
L v-t43 v-b’
v.1121
V-jill
SURFACE DI51RIBUTIOI
V-In
V31S1
-IlI0=
*
COW COMPRESSOR BOXv-]liE
Ti-I
___
--i. - LCAO
JTrS
_________
V,113
L
-,I WkOO{LI I
SURFACE
TUNNEL
U EIII
L, RID
flw --Iv-2
tI -I ii 1
V-12 I
_____
-
-- -I
2S- -
Il.v IV,I
V%I I- I V.rEKi.1rIçwI1.Dc11 I
L_J RECflER LJV-xe,mEff L_
v-%%: rI
1’
_____
RWv.3114 I*i I I I
-i
i1i
1*! - I *1I - - -I I r --I v-ij IIIt I I’I TUNNEl. - -I *I DISTRIBUTION v-ij lit Ii I H1001 DC1 I S S
LFflCT4D TO VS ICI ØZTUUN
iI[ iI [v-4"it IL Ji I[ ii
V121 L___
____
v4
v1I
v-I,,,
Li% COLD CO1PRESSOR BOX
3 II
-4
II r
I V-1 I
-----I
-
- -‘
--J
V11 -
I
I ‘i I!v-_4V-UI? I
MM
I*rM
FIGURE 10.5-1 SECTOR WARMUP
v_I-
v-i’ll
v*4
___
*-iosi V-l9
win’
-11 -v-iw
_________
a--r;: ±
Lst:: t nnc
[ HP UP 20K LPI_._.I v_ii II
________I
I_______________I
v-iwt I____ICS ‘r I I______I-
- 4K coin Box :::V44?
I L VI4M V1431
______
-
___
Iv-.aj V1412
4v-I,"
SURFACE DISTRIBUTIOI OX‘I.
V-Ill’
-
V1112
V
CR
gv-14a
Sal v-1532
Cth iII
I
__
Ihut e
I I I
IA1
__
I
__
-I-
SURFACE
TUNNEL I
V15i2
PnecJ1
rVThR V-mM
V1411
cIsu
-t
VM-I
Iv-iii
-I
--4
v-3d
-----1 I.IAbnpc
I aI ..
V1 V-I
,1t-
tim
SURFACE
TUNNCL
I°3
r-4-Ti rIl L J I ft
I
tvai MUS
-T-- J, r4L
I I I r -T r 1I I I I I
___________
I II-V I-v41 I I Ival
- M
____ ____ ____
-i L..__J’ ptcI_r. I--
4’ 4p 4I
I I PEC CR I II I
---
t - r VII TUHNEL.
DISTRIBUTION - v-al
L.
ze *
-
5
iIL
to Wa. *Lka .fnw stAid
ii ft - IL - iii IL Iii I -
I aar.annm II---
IUNNCLI DISTRIBUTION - an-I BoxL_
LEAD
V-fl’ V-II2
v-isLe v-15%-N
-1
V1414 I- I- I-P4-- CR I
VUII I
g
a
---I
FIGURE 10.5-2 SECTOR WARMUP, WARM GAS SUPPLY FROM PRESSURIZED WARM RETURN HEADER
VIif-. J.
TA&- I
-D v-I7 *v_II
St
0VINY
6N2 v-1371
9-
W1324
300K-801<COW BOXV-lI
-
aI
MP
2aK
V-l44- I
___
v-1442 I
_____________
- I
___
- _jV1443
I I
I
____________________
I V-i423
I P-S
80K - 4K COLD Bok v-i., HI
_______
V-143J
II L v-Il3
IV-I1 - V-1452 -
!IIu
_______________________
-
V
V-1421
V-MU
‘lit‘?V-I
fzr -
‘CCII
_____
fiShL -- --
v-I",
L
SURFACE
TUNNEL I
L
I WKOOIL I
PRECL
SURFACE DISTRIBIJTION BOX
L
COLD COUPRESSO Ox
2OC-IE
V
=1 -
*1
_______
r - -i - ,CflIN
! E
__
-4
V1511
*A$4ITh *aI
SURFACE
TUNNEL
Lr - - ii
-s LIF 11
HJ--3i ii II
a
r th&N. --
¶11- I T
:, -"*;-4 ‘
p N -‘
I VI4 Iv-uü O4EWCW, - - S I -* I I
I VSLVE I I I I I I II II-V3 ,-v,I I I I I
____
I‘
_____ _____ _____
ôJ L...._....J acwI Vll
v-iI rfl
____
I
____
u,cwvj III
___
v-louI Iwr1n I I I I
___
L IZI
II I!J4L-4’* j
-i
tt LJ L_i.J L.t.JTO WM ICLI Inusi ICR
IL "t
r
V
V1107 DV-IIN
----V1K1
V-1371
372
--p
_________ ________
v-I,"
1Dv5
V-322
SOCK - aoxCOLDBOXVII
-*4--
LHP lAP 20K LP
v-’Q4
531 V-t5
EIl--x. * 1v.niiøj
I I I III Ift.
I v-is,,
___________________
TUNNELDISIMaUTIONBOX
-4
-Dl
L
LEAI
*1
80K - 4K COLD BOX V1434
V1433
v-un *<
v-i,53 V-1431
:32
VI43
I V-022
V1421
H---
V151
PtCEILEP *SURFACE DISTRIBUTION OX
rV15R
Iv-,i.ci Iv-3m
I
____________
II.1
I
I’ ll
I&a
Li’a
a
I I
I V-4
v-_4 * - II VMVII I II I EV3 -w4I
2El I
______
V.4 lIt I
.. --
r, r,.
pq
V
V-all I I IlOflfll I I - I
vooi?thE NIflr 17Th I
iI1t.I
I
__
I
II _!_± I! - 1 I!
-J
aI
- j-I
CR
*1411--
V-Nfl
V-1112
V-1411
-I’ll
v
LflWNVM-fl
ijv.a
V WAa. gu
V.’?
I 1 IH-*t4V."
Vl
Sn I
___________
I
ye i
-C
JLEADCI
4.4j
T to stks .ttu-l *flM
LJ..4a
ILJ ;-
I
FIGURE 10.6-i SECTION REPAIR
IL
I.
I..
COLD COMPRESSOR !OX
1i Y
-I-ici
SURFACE
TUNNEL
SURFACE
TulillO.I- - - -
loI
r - --r
H1-
H
V-3I3
e---
v-lw *V-ISO
V-ID2
rAGE v-Ion
*TC
t_____
____
I iFJ1I4I I IVLVC I I I
I-V3 -v.! I2n’w
v-.4i. 1L __ JIVIrczn t___J
a v-iiI r
IM2ftC 1’ 1LDl I
II Iv-30i4 I
IOICIID I I I4 - -
I
___________________________________________________________________
v4ri rI JMIfl4 It HITUNNa 4 1
I OISIRIBUTIOU *Tv-a.i IJI II I
IBOX N1 I S S S
LLEAE ICLII To VMN HCtM Rt71N *aKt
nrranm Fi - - - t -
FIGURE 106-2 SECTION WARMUP USING WARM HEADER GAS AND BLOWER
-I
V- 361V-1P4
W V-nEZ
________
r r:M
4I MP 20K LP1_
cs
- 4K COLD DOX 4 I v-Her
L
4vIWJ
I i v- PWECP
SURFAC DISTRIBUTION Box
-it-----
_______ ____
V.
F:::::::T
TTTE T1IrI
v-ill.
‘1-1412
* J
-I
CR I
p IV-lw
v-li,,
2OIHX I
L
--t LEAOfln
SURFACE
TUNNEL
II
V-XO3’
-.rr
SURFACE
TUNNEL
r4
r
t WMVT- NOW
a
r
FlI1 -IL II
V-NW
II V
V-WII
Ij * v-Il
v-n.e
El:
Hi
I J t[ tt 1
.il Ii _-J i_L-I. -
-
b
L. - A. -
COLD CONPIZSWR BOXv-NI
-I
pwcmip ISURFACE DJSTRIBUTIOH
rV1542 V-ThU
Cl
r
I I I I1m I I I I
I "H I *1Tram - -
I TUNNEL - "I-DISTRIBUTION *t ‘-
L _.J
LEADcmD
jft
i1
_______
ii[I L iI [v.4van*
ii IL ii ft ii iF 1
ID WW IL1t tTI C
FIGURE 10.6-3 SECTION WARMUP USING 20K now AND HEATERS
0
9
- 121 L__
r
HP lIP 20K LI’
I-
10K - 4K CoLD aox
I1
L V-lfl
1!
V-NM
v-Ic,
v-u,,
V4431
_____
L -
v-fl.
1511
VLBOX
lv-i.v-f
______ _______
5 U I
.
SURFACE
TUNNEL I
rrlI-I
S UR C C
TUNNEL
V I*tlhlan
ING
I I I- ,ws I I
Ii-v3 1-vil Ippl!t ..4IIF 41
___ _____
-4 I ¶1
Do
v-i
tEl:
L
I N1-I
_________ ________
-
1- 20KI V-1441
cs V-1442
Vi143
: 80K - 4K COLD DOXI
_________
v-Il"
A l42
I L V-I43
T::::::T::!::::C i j_
_________________
I
_________
IY15t3
VISA? Vfl86N
suRrAcr
TUNNEL [fi
____ _________
I5acctflI tI s
________
I - --1
1---I TUNNEL "
" ‘°
I QISTRIBIJTJONI BOXL.
LEADCING
GflflIPW +i II
v-o1z
LEAD
CntN
v& ---1iI v-3
v-4 [
i Si ii
LPL_
v-1434 I _V14U
J
-,
V14t4 I
- I-Dc- CR I
Vi1i2 I
J
--V-1411
V81S
---I
r Wa... 10AMETISW
‘I- -I I I F r 1
L J L L Y1"2 I- IF Ir
- F-
MYIH44 I-,
I 4 I
::::
H
-ha- -
V1121 L....__.
jffajL
IL ii
i_liID S ItifiI !tTI4
IL Vt I
-
FIGURE 10.6-4 SECTION WARMUP USING HELIUM FROM PRESSURIZED WARM RETURN HEADER
*1
V-Ut I
V-1421
Iv-31fl
SURFACC
TUNNEL
I 1 r 9 -I VA4vC I I I I I
II-v3 Iv.I I I I Iv&I Iv-.4p 4I
_____ _____
flCR L - - - J L -- -lvi IV L.___J ,ccnc,t___J
_________________________________________________
I
___________________________________________________ ___________________________________________________
V-X.I r--1 r--, r-----
I 4UdFt I
__________ __________ ___________
IIV3014 I
1*rlnI
___
L L I
FIGURE 10.6-5 SECTION COOLDOWN AFTER MAINTENANCE
TOG,
r-
cjf
* *Ov..as V-so? *0w-ion
V-lam
Vi3á? V-i122 ]
I
r
___
::::: LflT :::nt,I HP hIP 20K LP..._.I I v- II v-i,,i r I-.-.p--..------ I
__p
v-n
ics I
____
-stI I I _Dc-CRII - I .__ v-uz I
v-i,i80K - 4K COLD BOX V*IIM
V-1422
I v-Hrç-*c1 II WIQI I$c II - II V.1153
V 431 j-DC I- -a-
V-I42 I I
______________________________________
/1511
v-ri
V Vi512
UIE.CSR 9I
___ _____
L
SURFACE
TUNNEL I
IrriILtCnI
I ViI7
v-I,,,-
Y-15M
I I II I
COLt COUPflSSOR lox
pttc-&
v-is., v-iw v.nCl
SURFACE DISTRIBUTION BOX
hir
11
V wasnt sn
-Dl0t
‘a’
SURFACE
TUNNU.
*-- LEAb
-ii IF4 - -1-i
IVa. E CLL.INO
r"fl VR
I
‘I II’
______
I’-7 J, r -" -,
- J + L JI -. - I II I vavtl I I I I I I
____
*I. L_D’L - - JiViflcj vt - - - J .cv.n L -
r ‘1 r----,NI
___
4j 4I
I I Isi L
TUNNELn.s N’s
DISTRIBU1IDtSc
L
ifli[
1
±
H
II
- -
II- I-----
I_ 1
iIL- ;- v.
]f t-4e* I1 Ii ‘I IF 11 1.1 I. .4 I- -j ..- -I
LJiLCADt t t t
‘0 *ttItM *CflsI .A
11. CRYOGENIC CONTROL SYSTEM
11.1 SECTOR REFRIGERATORCONTROL SYSTEM
The control systemfor the SRS is an integral part of the SSCmain cryogeniccontrol
systemMCCS. Theconceptfor theSSCcryogeniccontrol systemis underdevelopment
and thecurrentconceptfor the MCCS in termsof functionalitiesis describedbelow.Figures 11.1-1 and 11.1-2 show the various functionalities envisionedfor the
MCCS. Figure 11.1-1 showsthat theMCCS is divided into ten sectorrefrigerationcontrol
systems SRC. The SRC is located in the sector refrigerator site as shown inFigure- 11.1-2. Figure 11.1-2showsthat eachSRC is divided into a refrigeratorcontrol
system RCS and a tunnel control systemTCS. The RCS is dedicated to the sectorsurfacerefrigerator system,but it is an integralpartoftheSRC andtheMCCS.
The SSCmachinewill be operatedfrom a main acceleratorcontrolroom MACR.
The SSCcryogenic systemswill normally be remotelyoperatedfrom a main cryogenics
control room MCCR, and from sector cryogenicscontrol rooms SRC forcommissioning,maintenance,etc.
The actualreal-timecontrolof theequipmentwill be performedat theRCS andTCSlevels,with distributedprocessorscontrollersandcommunicationmodulesto remote110andto thecryogenicspeer-to-peernetwork Fig. 1 L1-2. Thesecontrollerswill be locatedabovegroundat the SCCSlocationin order to avoid exposureto thetunnelenvironment.Theonly control hardwareequipmentin thetunnelwill be remoteI/O, which will includeanalog-to-digitalanddigital-to-analogconversionmodules,specialI/O modulese.g.,fordiodetemperaturesensors,andcommunicationmodulesto remotecontrollers.
SRC functions such as supervisorycontrol, operatorinterface, and controllersoftwareconfigurationwill be performedin workstations;- -Theseworkstations contain
communicationmodulesto the peer-to-peernetworkandto theSSC global communicationnetwork,aswell asa databasewith all sectortag information.
Global control of the cryogenic systemwill be performedby the MCCS, whichincludes the functionality of the SRC workstation andaddsglobal supervisorycontrolanda communicationmodule to the office network seeFigure 11.1-1.
The SSC global communicationnetwork provides communicationbetween thedifferent systemse.g.,betweenthecryogenicsystemandthevacuumsystem,andaccessto a specific setof cryogenictagsandaddressesneededfor global machineoperationfromthe MACS. This networkis being developedby theURA/SSCL controlsgroupandit isbasedon Time Division Multiplex TDM technology.
The cryogenicspeer-to-peernetwork provides: communicationamong SCCScontrollerswithin a sectorand betweensectors;accessto all cryogenicI/O points; tagsforpurposesofcryogenicsystemoperation,maintenance,troubleshooting,andmodifications;andfor uploadanddownloadof SCCScontrollersoftware.
117
The field busprovidescommunicationbetweenremoteI/O andSCCScontrollersseeFigure 11.1-2. In order to guaranteea smoothintegrationwithin the SSCLenvironment,opensystemsarepreferredfor the MCCS. Thecriteria used for judging the opennessof asystemare:
* The systemadheresto a well-defined specificationavailableto the industry.
* Thespecificationis met by productsfrom severalindependentcompanies.
* Thespecificationis not controlledby a small groupof companies.
* The specificationis not tied to a specific machinearchitectureor technology.
Formal standardsare essentialasa basisfor open systems. URA will adhereto
internationalstandardsin the following areas:
a. Computercommunicationse.g., Manufacturing Automation Protocol[MAP], andManufacturingMessageSpecification[MMS]
b. Databasemanagementsystemse.g.,StructuredQueryLanguage[SQL]
c. Operatingsystemse.g.,UNIX
d. User interfacese.g.,X Windows
e. Controllerprogramminglanguagee.g.,WC 848
118
omcE NEVVORJC
MACR: Main AcceleratorControl RoomMACS: Main Accelerator Control SystemMCCR: Main Cryo Control RoomMCCS: Main Cryo Control SystemSCCR: SectorCryo ControlRoomSRC: SectorRefrigerator Control SystemRCS: RefrigeTatorControl SystemTCS: Tmnel ControlSystem
C1
n‘:2aIn
C0=g
a
IctcJJCJcJ I
MACS MCCS II, UI p 0 IU MI U I
SCCL COM NETWORK
C,,
0PEERTO PEER
BELOW GROUNDFIELD BUS
INDEX TO TERMINOLOGY
Beamtube-Thevacuumtubein which theprotonbeamtravels.
HEB - High EnergyBooster
CMS - Compressorsystem
Conditioning- The processof bringing a superconductingmagnetto its maximumcurrentwithout quenchesby operatingit at reducedtemperatureand atcuuentsabovethenominal operatingcunent. If themagnetis warmedup,all orpartof theconditioningprocessmayneedto berepeated.
Corrector- A small low-currentsuperconductingmagnetdesignedfor steeringcorrections dipole corrector, optical adjustmentsquadrupole andsextupolecorrectors,or compensationof magneterrorsin main magentsmultipole correctors.Correctionmagnetsresidein spool piecesandotherselectedlocationsin the magnetstring.
Dipole - A superconductingmagnetwith one northpoleand onesouthpole, whichproducesa uniformmagneticfield to bend thepath of theparticlebeam.
Dump Resistors- The magnetcurrentmust be quickly reducedto zerowhen aquench is detected,to preventburnout of the conductor. This isaccomplishedby connectingthe magnetstrings to dump resistorswhichdissipateall orpartof their storedenergy. Theseresistorsare locatedat thestring ends.
Half-cell - The smallestrepetitiveunit in the magnetsystemof the accelerator,consistingof a seriescombinationoffive dipoles,one quadrupole,and onespool piece. Each half-cell is 90 m long. It is expectedthat magnetquenchescanbe confmedto a singlehalf-cell.
MACR - Main acceleratorcontol room
MACS - Main acceleratorcontrolsystem
MCCR - Main cryogenicscontrolroom
Quench - The suddenreversion of a section of the conductor in a magnet to theresistive normalconductingstatedue to an energyinput from a disturbance.This zone increasesin temperatureand size so long as the current ismaintained,evenafter theoriginal disturbanceis over.
Quadrupole- A superconducting magnetwith two pairs of alternatingnorth andsouthpoles,which focustheparticlebeam.
RCS - Refrigerator control system
RFS - Refrigerationsystem
SCS - SectorStationCryogenicSystem.
SCCR- Sectorcryo controlroom.
121
Section- A seriescombination of twelvehalf-cells. At theend of eachsectionarecold valveswhich canisolateall of its cryogeniclines from thoseof thenextsection.
Sector- A parallelcombinationof four strings arrangedasshownin Figure 2.2-1.All connectionsto the SRS are made at this level. The main powerconnectionsfrom the magnetsto the sectorpower supplies and dumpresistorsaremadeat the feedcanandend can of eachstring in the sector.
Spool Piece - A can containing beam optics correctors,instrument leadfeedthroughs,and quenchprotection equipmentfor all magnetsin itsassociatedhalf-cell. Each spool piece also containsa cryostatvacuumbarrierbetweentwo adjacenthalf-cells. Every secondspool piececontainsa recooler.
SPRA - Standardspool with recooler.
SPRB- Spoolwith recoolerto connecta string of magnetsto a bypass.
SPRC- Spool with recoolerto connectan isolatedmagnetstring to a bypass.
SPRE- End spool with a recooleron the right side. The two partsof the spoolsarepart of differentcryogenicsectors.
SPRF- Feedspoolwith recoolerson both sides.
SPRI - Isolationspool with a recooleron the right side.
SPRS- Standardspool with recoolerand 2.5 meterextension.
SPRT- Spoolwith recoolerto connectan isolatedmagnetto abypass.
SPXA - Standardspool with no recooler.
SPXR - Returnbox.
SPXS- Standardspoolwith no recooleranda 2.5 meteremptycryostatextension.
SPXU - Spool with no recoolerand no vacuumbarrierstandardlength, usedintheutility-straight.
SRS- SectorRefrigeratorSurfaceSystem.
SRC- Sectorsw-facerefrigeratorcontrolsystem.
SSC- SuperconductingSuperCollider
String - A seriescombinationof four sectionsstarting with the sectorfeed spoolandendingwith the endspool.
Training - The processof bringing a superconductingmagnetto its maximumcurrentby a seriesof quenchesanddumpsat successivelyhighercurrents.This currentcapabilityis generallymaintainedaslong asthemagnetis keptcold, If the magnetis warmed up, all or part of the training processmayneedto be repeated.
TCS - Tunnelcontrolsystem
122