FZK/IRS-AS W. Hering, Ch. Homann 1
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
W. Hering, Ch. HomannW. Hering, Ch. Homann
Forschungszentrum KarlsruheProgramme NUKLEAR
P.O. Box 3640, D-76021 Karlsruhe, Germany
11th International QUENCH Workshop, October 25-27 2004
Table of Contents Table of Contents
• Motivation and objectives• Imbedding of Q-11 into Reflood Database • Status of Q-11 preparation • Summary and conclusions
Pre-test calculations of QUENCH-11 Pre-test calculations of QUENCH-11 (Q-L2) using S/R5 and ASTEC (Q-L2) using S/R5 and ASTEC
Pre-test calculations of QUENCH-11 Pre-test calculations of QUENCH-11 (Q-L2) using S/R5 and ASTEC (Q-L2) using S/R5 and ASTEC
FZK/IRS-AS W. Hering, Ch. Homann 2
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Motivation and objectives
• Open issues in SFD core refloodOpen issues in SFD core reflood
– Reduction in H2 uncertainty
– Perform a dry-out-reflood sequence test (Q-11)– Reflood with low capability systems (Q-11)– Assess risk of unintended core reflood (in case of LOOP)
• Pre-test work for QUENCH-11Pre-test work for QUENCH-11– Feasibility study (QWS-10)– Upgrade facility to meet requirements – First results of Q-11 pre-test experiments (Juri Stuckert)– Specification of step-by step approach to meet
requirements of QUENCH-11 (“Vorversuche”)
FZK/IRS-AS W. Hering, Ch. Homann 3
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Data baseData base
– EU-Programs– FZK Experiments– IRSN Phebus– OECD/NEA– USNRC– Plant accidents– LUTCH
Reactor typeReactor type
– PWR– VVER– BWR
Imbedding of Imbedding of Q-11 into Reflood Q-11 into Reflood
DatabaseDatabase
Core damage state prior to refloodinitiation
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Data source 0 1 2 3 4 5 6 7 K K/s sec K g s*rod
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CODEX 3/1 V 1420 / 1430 L 0,3 W 0,9 1
CODEX 3/2 V 1773 / 1916 L 0,6 W 0,9 <5
PARAMETR 1 V 1700 / ~1700 L ? Yes W 7 ?
PARAMETR 2 V B 1700 / ~2700 L ? No W 5 ?
QUENCH IBS05 P 1700 / 1750 L ? --- W 2,6 30
QUENCH-01 " 1830 / 1900 L 0,7 60 W 1,8 7 I
QUENCH-02 " 2470 / 2500 L " W 1,7 90
QUENCH-03 " Tiny 2450 / 2500 L " W 1,4 (85)
QUENCH-04 " 2110 / 2340 L " S 1,7 16 F
QUENCH-05 " Partial 2020 / 2270 L " S 1,7 7 G
Q-06 (ISP45) " 2060 / 2150 L " W 1,5 11 I/F
QUENCH-07 " B4C 2100 />2300 L " S 0,6 (68)
QUENCH-08 " Partial 2070 />2300 L " S 0,6 45 F
QUENCH-09 " B4C Tiny 2100 />2500 L " Yes S 1,8 87
QUENCH-10 (Q-L1) " 2180 / 2300 L " Air W 1,8 10 F
QUENCH-11 (Q-L2) " L 0.5 ? W 0.6 F
QUENCH-12 V t.b.d.
PBF SFD ST " ? / >2700 L 0.1 ? W 0,5 50
Phb SFD B9R2 " ? / 2150 L <0.2 Yes S S ?
CORA-12 " SIC ~2000 / 2300 L 1 --- W 1,4 ?
CORA-13 (ISP-31) " SIC Tiny ~2100 / 2500 L 1 --- W 1,4 48
CORA-17 B B4C ~2000 / 2300 L 1 Yes W 1,4 79
CORA-12 P SIC ? ? / >2400 L 2.2 --- W 130 75
TMI-2 P SIC ? / >2800 H 0.5 ? H 50-180 ~30 I
Paks (CTI) V 1600 / ? L 0.1 ? L W: ? ?
FZK/IRS-AS W. Hering, Ch. Homann 4
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Accident Termination Released Hydrogen fraction A
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Flow rate (g/s*rod) 1 2 3 4 5 6 7 1 2 3 4 5 6 7
TMI-2: 50-180 (BPT) T T T T TLoft LP-FP2: 130 L L L ? ? L L ? ?very high (> 9.0) ? ? ? ? ? ? ?
All HP-SI + LP-SI ? ? ? ? ? ? ?high (2.0 - 9.0) P P ? ? ? P P ? ? ? ?
All LP-SI Q ? ? ? Q ? ? ? ?medium (1.0 - 2.0) C Q Q ? ? C Q Q ? ?
All HP-SI Q C C ? ? Q C C ? ?low ( 0.6... 1.0) Q Q ? ? ? Q Q ? ? ?
single HP-SI X Q ? ? ? ? X Q ? ? ? ?very low (< 0.7) ? Q-L2 ? ? ? ? ? ? ? ?
other ? ? ? ? ? ? ? ? ? ? ? ? ? ?Accident progression
Core damage state prior to refloodinitiation
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Q-L2 in the reflood map Q-L2 in the reflood map Experimental data base: Depending on Experimental data base: Depending on Reflood Mass Flow RateReflood Mass Flow Rate (RMFR) and (RMFR) and Core Damage State (CDS)Core Damage State (CDS)
Steam Steam starvedstarved(PARAMETR) (PARAMETR)
Q-11 Q-11 (Q-L2)(Q-L2)Q-11 Q-11 (Q-L2)(Q-L2)
Color codingA H2< 20%
B 20 < H2 < 50%
C H2 > 50%
Cat A & B
Cat B & C
Data sourcesC CORAQ QUENCHX CODEXP ParametrL LOFT LP-FP2T TMI-2
FZK/IRS-AS W. Hering, Ch. Homann 5
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Step-by-step approach to QUENCH-11Step-by-step approach to QUENCH-11
Test objectives Test objectives - Extend QUENCH facility to low mass flow rate scenarios Extend QUENCH facility to low mass flow rate scenarios
(ceasing pumps or AMM)(ceasing pumps or AMM)
- Prepare facility for experiments with free water surfacePrepare facility for experiments with free water surface
- Investigate scenario with low steam availability Investigate scenario with low steam availability (app. 1g/s 0.04 g/rod*s)
Stepwise approachStepwise approach
- Component tests q11v1Component tests q11v1 - Guidance and control test q11v2 (T < 600 K)Guidance and control test q11v2 (T < 600 K)
qualification of input decks qualification of input decks
- Design basis reflood test q11v3 (T < 1400 K) Design basis reflood test q11v3 (T < 1400 K) extend database also for DBA codes extend database also for DBA codes update of input decks update of input decks
QUENCH-11 (Q-L2)QUENCH-11 (Q-L2)
FZK/IRS-AS W. Hering, Ch. Homann 6
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Best simulation of reactor conditions
with Q-L2
ReactorReactor Consider real volumes
in the RPV: Contribution of downcomer: additional 80 to 120 % of the free core flow area
• Pre-test calculationsPre-test calculations– Pre-test experiments to
assess input decks
– Check independent control of: 1. evaporation rate and 2. bundle heat-up
FZK/IRS-AS W. Hering, Ch. Homann 7
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Tools for pre-test calculations and Tools for pre-test calculations and post-test analysespost-test analyses
SCDAP/RELAP5 mod 3.2.irs:SCDAP/RELAP5 mod 3.2.irs:specially modified for out-of-pile facilities specially modified for out-of-pile facilities basic toolbasic tool
ASTEC V1.x (contribution to SARNET):ASTEC V1.x (contribution to SARNET): Check more possible test scenarios Check more possible test scenarios
(after qualification using S/R5) (after qualification using S/R5)
Parameter studies (fast running code)Parameter studies (fast running code)
Due to manpower restrictions: Due to manpower restrictions: Code validation focussed on DIVA (~ICARE2) Code validation focussed on DIVA (~ICARE2)
FZK/IRS-AS W. Hering, Ch. Homann 8
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Pre-test Q-11v2
• Objectives:
Steam flow control with Auxiliary heater power
Control bundle heat-up
Response time of additional water inflow
Qualification of fluid measurement
Test low mass flow-rate reflood (< 0.7g/s*rod)
FZK/IRS-AS W. Hering, Ch. Homann 9
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
First post test analysis
• Draft findings:
Water ejected due to flashing even
Bundle voided z> 0.25 m
Temperature rise linearly until bundle power reduced
Not observed in experiment
FZK/IRS-AS W. Hering, Ch. Homann 10
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Post-test Q-11v2
• Draft findings:
Boil-off rate larger: z > 0.5 m,smaller: z < 0.5 m
Bundle temperatures underestimated
Flashing observed (due to initial conditions)
Check initial conditions and heat losses to environment at “low” temperatures
FZK/IRS-AS W. Hering, Ch. Homann 11
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Whole scenario
Pre-test calculationPre-test calculation(before Q-11v2):(before Q-11v2):
– Q-11v3 delivers50-60 µm oxide layer(reactor specific)
– Q-11v3 reflood phase simulates Accumulator driven core reflood
– Max temperatures: - Q-11v3: < 1350 K - Q-11 ~ 2600 K
Next steps:Next steps:
1. update input deck
2. Check sequence Q-11v3 and Q-11
FZK/IRS-AS W. Hering, Ch. Homann 12
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Reasonable simulation of axial temperature profile during heat-up phase
Onset of final transient OK (t< 7000s)
Temperature peak prior / during reflood underestimated (like most of the codes in ISP-45)
ASTEC V1.2 in work
Validation: ASTEC results for ISP-45Validation: ASTEC results for ISP-45
FZK/IRS-AS W. Hering, Ch. Homann 13
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
ASTEC: draft
results for Quench-11
Comparable to S/R5 calculations
Deviations during cool-down are due to lacking reflood model in (ASTEC V1.1)
Much faster than S/R5
Shows Temperature evolution in the core as well as shroud insulation
FZK/IRS-AS W. Hering, Ch. Homann 14
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Summary and conclusions (1)
Post test analysis identified unexpected deviations Post test analysis identified unexpected deviations in the S/R5 facility model: in the S/R5 facility model: not required before because experiments not required before because experiments
start at higher temperaturesstart at higher temperatures
Q-11v2 proved successfully step-by-step Q-11v2 proved successfully step-by-step approach to prepare Q-11approach to prepare Q-11
Free water level and steam mass flow rate Free water level and steam mass flow rate could be controlled, although predictions of pre-could be controlled, although predictions of pre-calculations differ from experiment calculations differ from experiment
QUENCH facility, originally not designed for a free water QUENCH facility, originally not designed for a free water level at lower end of the bundle is now able to simulate level at lower end of the bundle is now able to simulate that featurethat feature
FZK/IRS-AS W. Hering, Ch. Homann 15
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany
Q-11v3 – Q11 pre-test calculations initiated Q-11v3 – Q11 pre-test calculations initiated using results of Q-11v2using results of Q-11v2
– Q-11 can be performed as proposed (QWS-10)– Database will be released to LACOMERA partners– Post-test analyses with ASTEC will be continued
with know-how from S/R5
SFD-Research focused on: SFD-Research focused on: SARNET: Validation of ASTEC V1.x by code to code
and code to data
Improvement and extension of the FZK reflood map
Detailed simulation with S/R5 to supply integral codes with reliable boundary conditions for Q-11
Summary and conclusions (2)
FZK/IRS-AS W. Hering, Ch. Homann 16
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
11th International QUENCH Workshop, Karlsruhe, Germany