page 1 saferib i - cern/geneva 30.10. - 01.11.2002 status of safety analyses for the ess target...
TRANSCRIPT
![Page 1: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/1.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 1
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Status of Safety Analyses for the ESS Target
R.Moormann, R.Bongartz, W.Kühnlein, J.Marx, H.Schaal, K.Verfondern (FZJ)
P.Berkvens (ESRF), P.Wright (RAL)
![Page 2: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/2.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 2
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Artist‘s view of the ESS Facility
![Page 3: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/3.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 3
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Main parameters
![Page 4: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/4.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 4
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Scheme of ESS target and of mercury circuit (15 t Hg, max. operation temperature: 250°C, max. temperature increase by decay heat: 35 °C)yellow =target block, red = mercury
Proton beam
![Page 5: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/5.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 5
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
-The target is the only component in Spallation Sources, which requires detailed accident analyses: accidents, harming the public, are imaginable only for the target due to its substantial radiotoxic and chemical toxic inventory. Other components (accelerators etc.) need safety considerations for normal operation/- abnormal events only.
The preliminary safety analysis report (PSAR including updates) for the SNS target is under review with respect to its applicability for ESS
![Page 6: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/6.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 6
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Short description of PSAR Procedure of PSAR
(preliminary safety analysis report) :- screening of possible events- rough estimation of consequences and
frequencies (limited credit on safety measures = ‘unmitigated’ estimations)
- identification of relevant accidents by ‘risk
binning’; (risk = dose * frequency)
- cut off criteria: low frequencies (< 1.e-6/a) and low consequences (< 1 mSv)
![Page 7: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/7.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 7
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
- more detailed estimation of source term and consequences for relevant accidents (‘unmitigated’ estimations)
- in case of transgression of dose limits:repetition of source term/consequence/- frequency estimations assuming additional ‘mitigating’ safety measures
- stepwise increase of accuracy, until dose limits are met (advantage: reduction of effort, identification of really important safety measures)
![Page 8: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/8.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 8
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Relevant accidents identified:• Fire within the target building• Hydrogen/moderator explosion with and without
subsequent fire• Loss of confinement (Leak in the target circuit)
– [Loss of mercury flow]– [Loss of heat sink]
• [Target hull heat-up by misadjusted proton beam]• Earthquake followed by explosion with and
without following fire• Crane drop accident
![Page 9: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/9.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 9
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Safety work at ESS
Main results of PSAR/SNS review are:
- PSAR/SNS is a valuable basis for ESS safety work
- Additional accident to be considered in case of a Be-reflector: Be-reflector fire
- European conditions require a more detailed safety analysis than performed within PSAR/SNS for the following reasons:
![Page 10: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/10.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 10
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
• larger ESS radioactive inventory• smaller distance ESS – receptor• conservative consequence model for ESS
required, not a realistic one as for SNS• consideration of ingestion pathway for ESS
accidents required (contrast to SNS)• lower dba dose limits in EU:
effective dose/dba: 50 mSv in D 250 mSv for SNS
![Page 11: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/11.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 11
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Safety relevant nuclides in mercury target:
nuclide boiling point [K]
ESS target inventory
[GBq]
half life [d]
radiation type
dose/emission 1) ground cloud inhalation ingestion shine (γ) [ / ]Sv GBq
H-3 ( )HTO 373 2.3e-9 3) 4.6e-8 2) H-3 ( )HT 14
5.6 5 e( )total
4500 weak β 0 0 1.5e-11 3,4) 3.3e-9 4)
I-124 387 3100 4.2 β,γ 2.8e-6 1.0e-8 3.0e-5 3.4e-3 I-125 „ 14000 60 γ 1.8e-6 1.0e-10 1.8e-5 2.3e-3 I-126 „ 630 13 β,γ 3.9e-6 4.2e-9 6.3e-5 7.6e-3
Hg-193 629 1.9 6e 0.16 γ 3.6e-8 1.7e-9 6.5e-9 2.5e-10 Hg-194 „ 2.1 5e 1.9 5e γ 6.1e-3 1.3e-13 1.3e-6 5.0e-7 Hg-195 „ 3.2 6e 0.42 γ 7.5e-8 1.7e-9 8.1e-9 6.3e-10 Hg-197 „ 2.2 7e 2.67 γ 1.1e-7 5.2e-10 2.0e-8 3.0e-9 Hg-203 „ 1.5 7e 47 β, γ 7.5e-6 2.2e-9 1.8e-7 8.1e-9 Gd-148 3546 3.5 4e 2.72 4e α 0 0 2.2e-3 4.0e-7 Hf-172 4875 7.3 5e 683 γ 2.8e-4 7.7e-10 1.3e-5 1.9e-9 Au-195 3081 4.2 6e 186 γ 3.1e-6 6.2e-10 2.2e-8 5.9e-10
1) , (70 ), German directives for design basis accidents infant a continuous ingestion and ground shine effective doses (except for iodine ), : 250 , : 25 , thyroid minimum distance m emission height m2) preliminary ingestion model of , German rules3) ( ), including HTO resorption by skin preliminary model4)HT- oxidation to HTO in soil considered
: = , = Volatility classes green high volatile blue me ( ), = rcury intermediate volatility yellow low volatile
Overview on radiologically most relevant nuclides in the ESS-target (5 , 30 )MW y continuous operation
![Page 12: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/12.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 12
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Note: Long lived actinides are not found in spallation sources
Comparison of activities in LWR and ESS
![Page 13: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/13.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 13
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Conclusion on comparison of inventories:• Determination of spallation yield for long-lived
nuclides (Hg-194, Gd-148) is of particular relevance: ESS will perform evaluation of Hg irradiation experiments of ORNL, performed at SINQ
• Even for individual short lived nuclides the spallation yield is fairly uncertain (which is compensated by the large number of nuclides). Accordingly, short term Hg irradiation experiments are advisable
![Page 14: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/14.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 14
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Comparison of radiotoxicity and chemical toxicity of mercury
• Comparison is problematic, because only incorporation effects are comparable
• Comparison for toxicity by inhalation between the total inactive Hg-inventory and the inventory of one individual nuclide (Hg-197) reveals, that the chemical toxicity is about a factor of 10 - 30 higher than the radiotoxicity of Hg-197
![Page 15: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/15.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 15
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
• Nevertheless, due to strong ground shine (Hg-194) and due to the large number of other radiotoxic nuclides, we expect, that radiotoxicity dominates the overall toxicity.Chemical toxicity may however not be neglected.
![Page 16: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/16.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 16
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Loss of confinement accidents1. Probabilistic and system studies
No Released media
Released activity
Probability / dose limit (mSv)
Unmitigated dose (mSv)
Counter measures
Remarks
Large failure of target confinement, release of Hg and cooling water into core container at operating temperature; release into environment via vacuum system, off gas system and stack
3.1-4
Hg, cooling water
H-3, Hg-,I-isotopes
SNS: U/50 ESS: A/0.3 per path
SNS: 3.2 ESS: > Limit
HEPA-Filter H-3-filter ?
Large failure in target circuit, release of Hg into target cell at operating te mperature; release into environment via Primary Containment Exhaust System (PCE) and stack
3.1-7
Hg “ SNS: A/5 ESS: A/0.3 per path
SNS: 2.2 ESS: >Limit
HEPA-Filter Hg-Adsorber
“
Failure of Hg-flow, local boiling, Hg- and cooling water release into core vessel via leak generated by proton beam, partial evaporation of Hg, release into environment via overpressure valve and stack
3.1-12
Hg, cooling water
“ SNS: A/5 ESS: A/0.3 per path
SNS: 200 ESS: >> Limit
Beam shutdown
Time for beam shutdown?
Failure of target heat sink, Hg- and cooling water release into core vessel via leak generated by proton beam, partial evaporation of Hg, release into environment via overpressure valve and stack
3.1-13
“ “ SNS: A/5 ESS: A/0.3 per path
SNS: > 250 ESS: >> Limit
Beam shutdown
Time for beam shutdown?
Leak in cooling water system (target shroud), release via target cell or core container and stack into environment
3.3-1
Cooling water
H-3 SNS: A/5 ESS: A/0.3 per path
SNS: 0.05 ESS: > Limit
H-3 filter in –PCE?
HT, HTO ?
Leak in reflector cooling system, release of cooling water into auxiliary system building, release into environment via stack
3.3-12
D2O H-3 SNS: A/5 ESS: A/0.3 per path
SNS: 0.22 ESS: > Limit|
H-3 filter in SCE?
“
Relevant ESS dba
A = anticipated within ESS lifetimeU = unlikely
![Page 17: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/17.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 17
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
2. Deterministic examinations• Hg/H-3 thermochemistry has to be examined • JSNS work indicated, that mercury iodides (lower volatility than I2) may be formed:
- PSAR/SNS assumes a pronounced iodine release in loss of confinement accidents, because the chemical status of iodine is considered as elemental (high volatile). Resulting emissions are too high for ESS conditions.- Thermochemical calculations (using ORNL-code SOLGASMIX-PV) at ESS quantified the chemical composition. Validation will be performed.
![Page 18: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/18.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 18
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Equilibrium composition of an Hg/I and of an Hg/I/Fe system
Results of SOLGASMIX-PV
![Page 19: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/19.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 19
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
Additional target and moderator safety work
Other accident classes in examination for ESS (probabilistic, system, source term and dose studies) are:
• External events (earthquake, fire, airplane crash..)
• Internal explosions
![Page 20: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/20.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 20
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
• CFD (CFX-Code): calculations on distribution of moderator within target cell/- building in accidents (burnable gas mixtures etc.):
Leak in H2-pipe with spontaneous evaporation
1.5 kg of H2 released in 30 s
Air ingress with 0.15 kg/s at 288 K
• CFD-calculations on particle (Hg-droplets) transport in case of accidents
Examinations on moderator explosions
![Page 21: Page 1 SAFERIB I - CERN/Geneva 30.10. - 01.11.2002 Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ Status of Safety Analyses for](https://reader030.vdocuments.us/reader030/viewer/2022032703/56649d1b5503460f949f0964/html5/thumbnails/21.jpg)
Status of safety analyses for the ESS target Rainer Moormann, PES-FZJ
Page 21
SAFERIB I - CERN/Geneva30.10. - 01.11.2002
General ESS safety work• Decommissioning, final waste disposal
• Activity transport with ground water flow
• Consequence estimations for accidents using COSYMA model (planned)
• Selected design work for safety systems
• Shielding philosophy and design