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U.S. Department of Energy
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Integrated analysis of DCH in Surry

Conference ·
OSTI ID:10135967

An evaluation of the key elements affecting Direct Containment Heating (DCH) was performed for the Surry plant. This involved determining the dominant high pressure core damage sequences, the probability of proceeding to vessel breach at high pressure, the DCH loads, and the containment strength. Each of these factors was evaluated separately, and then the results were combined to give the overall threat from DCH. The maximum containment failure probability by DCH for Surry is 10{sup {minus}3} when considering four base DCH scenarios and using the two-cell equilibrium (TCE) model. However, higher contamination failure probabilities are estimated in sensitivity cases. When the depressurization and containment loads aspects are combined, the containment failure probability (conditional on station blackout sequence) is less than 19{sup {minus}2}. CONTAIN calculations were performed to provide insights regarding DCH phenomenological uncertainties and potential conservatisms in the TCE model. The CONTAIN calculations indicated that the TCE calculations were conservative for Surry and that the dominant factors were neglect of heat transfer to surroundings and complete combustion of hydrogen on DCH time scales.

Research Organization:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Organization:
Nuclear Regulatory Commission, Washington, DC (United States)
DOE Contract Number:
AC04-94AL85000
OSTI ID:
10135967
Report Number(s):
SAND--93-2261C; CONF-931079--22; ON: DE94008870; BR: GB0103012
Country of Publication:
United States
Language:
English