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Title: Analysis of long-term station blackout at Peach Bottom using MELCOR

Conference · · Transactions of the American Nuclear Society; (United States)
OSTI ID:7089057
 [1]
  1. Brookhaven National Lab., Upton, NY (United States)

MELCOR is a fully integrated computer code that models all phases of the progression of severe accidents in nuclear power plants. It is being developed for the US Nuclear Regulatory Commission (NRC) by Sandia National Laboratories and is designed to provide an improved severe-accident/source term analysis capability relative to the older source term code package (STCP). Brookhaven National Laboratory has a program with the NRC to verify and apply the MELCOR code to severe-accident analysis for several plants. This paper presents the results from a MELCOR calculation of a long-term station blackout accident sequence with failure to depressurize the reactor vessel. Peach Bottom, a boiling water reactor with Mark I containment, was used in the analysis. The paper also compared MELCOR predictions with STCP calculations for the same sequence. This sequence assumes that batteries are available for 6 h following loss of all power to the plant. Station blackout sequences have often been determined to be important contributors to the risk from severe accidents. Following battery failure, the reactor coolant system (RCS) inventory is boiled off through the relief valves by continued decay heat generation. This leads to core uncovery, heat-up, clad oxidation, core degradation, relocation, and, eventually, vessel failure at high pressure. The STCP has calculated the transient up to 13.5 h after core uncovery. MELCOR calculations have been carried out to 16.7 after core uncovery. The results include the release of source terms to the environment.

OSTI ID:
7089057
Report Number(s):
CONF-901101-; CODEN: TANSAO
Journal Information:
Transactions of the American Nuclear Society; (United States), Vol. 62; Conference: American Nuclear Society (ANS) winter meeting, Washington, DC (United States), 11-16 Nov 1990; ISSN 0003-018X
Country of Publication:
United States
Language:
English

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