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PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
PKL III Test Facility
Integral test facility simulating a 1300 MW PWR
• 4-Loop configuration
• All relevant safety and operational systems on the primary and secondary side without turbines and condensers
• Volume and power scale 1:145
• Elevations 1:1
Objectives
• Thermal hydraulic system behavior under accident situations
• Verification and Optimization of cool-down procedures
• Database for the validation of computer codes
• Demonstration of safety margins
• Resolution of safety issues of current interest
• Training of the operating staff
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
PKL III Boron Concentration Measurements
x
COMBO
x x
HP- / LP-Injection
Loop 1}Loop 1
Fluid temperature
Wall temperature
Combi. Temp. Sensor
Grab sampling
CL 1+2
Loop 1
Loop 1-3
Loop 1COMBO
Loop 1-3
Continuous Measurement of
Boron Concentration (COMBO)
Counter Tubes Neutron source
Coolant to bemeasured Pipe
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
PKL-Tests Concerning Boron Dilution
Background:
� Low borated water entering the core can lead to local recriticality and
thereby to a power excursion
� A necessary condition for this to happen is the formation of low borated water slugs in the primary and their transport to the core without sufficient mixing
� Formation of low borated water slugs might occur by separation of borated
and almost boron free coolant within the primary, e.g. by
→ Small Break and Reflux-Condenser Conditions
→ Loss of RHRS under shut-down conditions followed by steam production in the core and condensation in the SG
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
� Break in the hot leg of the pressurizer loop(40cm2)
� 100 K/h cooldown of the SG-secondaries
� HP-SIP: into all 4 loops- E1.1 cold leg- E2.1 hot leg
� Continuous boron concentration measurement (COMBO) at the RPV inlet- E1.1 in loop 1- E2.1 in all 4 loops
PKL-Tests Concerning Boron Dilution after SB-LOCA
Symmetrical injection into all 4 loops (E1.1, E2.1)
SG SG
PRZ
RPV
Borated waterSteamLow borated water
Initial conditions
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
PKL-Tests Concerning Boron Dilution after SB-LOCA
� Break in the cold leg of loop 1 (32cm2)
� 100 K/h cooldown of the SG-secondaries
� 2 out of 4 HP-SIPs (cold leg, 1 in break loop)
� Continuous boron concentrationmeasurement(COMBO) at the RPV inletin all 4 loops
Maximum amount of unborated water: cold leg injection (E2.2)
SG SG
PRZ
RPV
Borated waterSteamLow borated water
Initial conditions
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
PKL III E2.2 - Transport of Condensate Slugs due to Restart of Natural Circulation
0
1000
2000
3000
3000 3200 3400 3600 3800 4000
Bor
on c
once
ntra
tion
at R
PV in
let Boron concentration at RPV inlet in loops 1, 2, 3 and 4
[B]-curves represent floating average (20 s)
in p
pm
0
1
2Natural circulation in loops 1, 2, 3 and 4
Mas
s flo
w in
kg/
s
T ime aftertest start
in s
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
PKL III E3.1: Loss of RHRS
Scenario� Total failure of RHRS
when the reactor isshut down, e.g. forrefuelling (primarysystem still closed)
� 2 SGs filled with water,one of both (SG 1)ready for operation
Objectives� Takeover of residual
heat removal by theSG ready for operation
� Evolution of localboron distribution
Initial Conditions
SG 4Psec = 1.0 bar
SG 1Psec = 1.0 bar
SG 2Psec = 1.0 bar
SG 3Psec = 1.0 bar
Pprim ~ 1 barTcore, out = 60 °C
Decay heat = 0.7 %
[B] = 2200 ppm, homogeneous
RHR in operation fortest preparation -but fails at test start
Water prim., subc. > 10 KN2 primary
Water sec.Air sec.
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
PKL III E3.1: Loss of RHRS
� Failure of RHRS has lead to:
���� Core heat up and steam production
���� Increase in liquid level and primary pressure
���� Condensation in the SGs
� Heteregenous behavior inthe individual SG U-tubes:
���� Slug of subcooled water in the long U-tubes
���� Intermittend overflow of low borated condensate in the small U-tubes
Situation after 7 - 8 hours
SG 4Psec = 1.0 bar
SG 1Psec ~ 2.0 bar
SG 2Psec > pprim
SG 3Psec = 1.0 bar
Pprim = 5 barTcore, out = 150 °C
Decay heat = 0.7 %
[B] = 2200 ppm, inhomogeneous
Water prim., subc. > 10 KWater prim., subc. < 10 K
Water/steam mix. prim.N2/steam mix. prim
[B] = 800 ppm
[B] = 4400 ppm
1400 ppm
[B] = 1200 ppm
Q�
1700 ppm
COMBO[B]
m�
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
0
1000
2000
3000
4000
5000
-4500 0 4500 9000 13500 18000 22500 27000 31500 36000 40500 45000
Boron concentration in ppm
Time in s
COMBO in loop seal 1(continuous measurement)
Sampling at DC bottom
Sampling at core inlet
Sampling at core outlet
0
1
2
3
4
5
6
7
8Pressure in bar
Primary
SG 1 secondary
Controlling ofsec. pressurein SG 1
Begin of ACC injection
Return toRHRS
Failureof RHRS
PKL III E3.1: Loss of RHRS
� Primary pressure stabilizesafter about 5 h at 5 bar
� Heat transfer by steamproduction in the coreand condensation in theSG in operation
� Intermittend overflow ofcondensate (low boratedwater) to the cold side insome SG U-tubes
�Slow but continuousdecrease in boronconcentration at theSG outlet and withsome delay also inthe RPV downcomer
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
Application of PKL Test Results to PWR Plants
Use of the PKL Results
� Understanding of the thermal hydraulic behavior during theinvestigated accident scenarios� System behavior� Local behavior (e.g. SG tubes)
� Application on NPP operation� Contribution to the resolution of a safety issue of current interest (e.g. size
of accumulated low borated water is limited and smaller than expected,restart of NC does not occur simultaneously in several loops)
� Impact on operating procedures
� Support for Code analyses� Validation and development of TH system codes� Boundary conditions for further experimental and/or analytical
investigations on mixing in the RPV downcomer
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
New Program PKL - 2
> Starting in the second half of 2003
> Program period: 3 years
> 7 Experiments (partly with several test runs)
PKL Presentation June 2003.ppt - 06-2003 - R-904748 - FANP TGT1/Um
New Program PKL - 2
Proposed Topics of Investigation(priorities according to comments during 4. PRG and further feedback by the participants)
� Tests on loss of residual heat removal under shut-downconditions with closed RCS (3 Tests with 8 Test Runs)
� Tests on boron dilution after SB-LOCAs (2 Tests)
� Test on loss of residual heat removal under shut-down conditionswith open RCS (1 Test with 2 Test Runs)
� Test on boron precipitation during LB-LOCA (1 Test)
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