Estimate of LOCA-FI plenum pressure uncertainty for a five-ring RELAP5 production reactor model

Technical Report · Mon Mar 01 00:00:00 EST 1993

DOI:https://doi.org/10.2172/6283317· OSTI ID:6283317

Griggs, D P

The RELAP5/MOD2.5 code (RELAP5) is used to perform best-estimate analyses of certain postulated Design Basis Accidents (DBAs) in SRS production reactors. Currently, the most limiting DBA in terms of reactor power level is an instantaneous double-ended guillotine break (DEGB) loss of coolant accident (LOCA). A six-loop RELAP5 K Reactor model is used to analyze the reactor system behavior dozing the Flow Instability (FI) phase of the LOCA, which comprises only the first 5 seconds following the DEGB. The RELAP5 K Reactor model includes tank and plenum nodalizations having five radial rings and six azimuthal sectors. The reactor system analysis provides time-dependent plenum and tank bottom pressures for use as boundary conditions in the FLOWTRAN code, which models a single fuel assembly in detail. RELAP5 also performs the system analysis for the latter phase of the LOCA, denoted the Emergency Cooling System (ECS) phase. Results from the RELAP analysis are used to provide boundary conditions to the FLOWTRAN-TF code, which is an advanced two-phase version of FLOWTRAN. The RELAP5 K Reactor model has been tested for LOCA-FI and Loss-of-Pumping Accident analyses and the results compared with equivalent analyses performed with the TRAC-PF1/MOD1 code (TRAC). An equivalent RELAP5 six-loop, five-ring, six-sector L Reactor model has been benchmarked against qualified single-phase system data from the 1989 L-Area In-Reactor Test Program. The RELAP5 K and L Reactor models have also been subjected to an independent Quality Assurance verification.

• Research Organization: Savannah River Site (SRS), Aiken, SC (United States)
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC09-89SR18035
• OSTI ID: 6283317
• Report Number(s): WSRC-TR-93-127; ON: DE93018179
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
L REACTOR
LOSS OF COOLANT
COMPUTERIZED SIMULATION
EVALUATION
F CODES
MULTIPHASE FLOW
NUCLEAR POWER PLANTS
QUALITY ASSURANCE
R CODES
REACTORS
VALIDATION
ACCIDENTS
COMPUTER CODES
FLUID FLOW
HEAVY WATER MODERATED REACTORS
NUCLEAR FACILITIES
POWER PLANTS
PRODUCTION REACTORS
REACTOR ACCIDENTS
SIMULATION
SPECIAL PRODUCTION REACTORS
TESTING
THERMAL POWER PLANTS
210400* - Power Reactors
Nonbreeding
Otherwise Moderated or Unmoderated
990200 - Mathematics & Computers