Design report: SCDAP/RELAP5 reflood oxidation model

Technical Report · Thu Oct 01 04:00:00 EDT 1992

DOI:https://doi.org/10.2172/10115541· OSTI ID:10115541

Coryell, E W; Chavez, S A; Davis, K L; Mortensen, M H

Current SCDAP/RELAP5 oxidation models have proven to under-predict oxidation, and therefore hydrogen production, when modeling reflood during in-pile tests. As an example, while OECD LOFT Experiment LP-FP-2 shows significant increases in temperature and pressure during reflood due to increased oxidation, only minimal additional oxidation is currently predicted with SCDAP/RELAP5. Since SCDAP/RELAP5 predicts a steam rich environment during reflood, the parameter limiting oxidation must be the availability of zircaloy. Two phenomena, not currently modeled, may provide the necessary unoxidized zircaloy during reflood: (1) localized steam starvation prior to reflood, caused by debris blockage or hydrogen generation, or (2) shattering of oxidized cladding during reflood. The objective of this design report is to develop new models to accurately predict zircaloy cladding oxidation during the temperature transients prior to and during reflood. Evidence compiled from postirradiation examination (PIE) of fuel bundles subjected to severe accident conditions from several in-pile tests is used to identify mechanisms for additional cladding oxidation during reflood and to develop specific criteria to determine when these mechanisms are applicable.

• Research Organization: EG and G Idaho, Inc., Idaho Falls, ID (United States)
• Sponsoring Organization: Nuclear Regulatory Commission, Washington, DC (United States)
• DOE Contract Number: AC07-76ID01570
• OSTI ID: 10115541
• Report Number(s): EGG-RAAM--10307; ON: DE93005045
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210200
22 GENERAL STUDIES OF NUCLEAR REACTORS
220600
99 GENERAL AND MISCELLANEOUS
990200
CLADDING
COMPUTER CALCULATIONS
COMPUTERIZED SIMULATION
HYDROGEN
LOFT REACTOR
LOSS OF FLOW
MATHEMATICAL MODELS
MATHEMATICS AND COMPUTERS
OXIDATION
POWER REACTORS
NONBREEDING
LIGHT-WATER MODERATED
NONBOILING WATER COOLED
R CODES
RESEARCH
TEST
TRAINING
PRODUCTION
IRRADIATION
MATERIALS TESTING REACTORS
S CODES
TESTING
ZIRCALOY