Project Details
Problem Statement
Severe accident analyses, with respect to nuclear reactors, are needed to support industry in their compliance with regulatory requirements, to understand and learn from past incidences, and to support the development of enhanced accident response guidelines and technology.
Technical Approach
Typically, expertise with the severe accident codes MELCOR, MACCS, WinMACCS, CORQUENCH, and MAAP is drawn upon to analyze the progression of a severe accident, potential radioactive releases, and offsite consequences. Other efforts include developing and validating new models for specific phenomena in order to reduce uncertainty in severe accident analyses. The SCALE code suite, developed at ORNL, is also used to establish radionuclide inventories.
Benefit
Past significant efforts include calculating doses and atmospheric releases for the TMI-2 and Chernobyl Accidents and for postulated accident scenarios at Peach Bottom Unit 2, Grand Gulf Unit 1, and other sites.
To support the U.S. response to the 2011 accidents at the Fukushima Daiichi site in Japan, the accident progression at Unit 3 was analyzed, the response of Unit 4’s spent fuel pool was simulated, and detailed analysis of the ex-vessel core melt was performed for Unit 1. We continue to participate in expert panels to identify and address gaps in our severe accident knowledge base and to develop and disseminate insight from the accidents and decommissioning activities at the Fukushima Daiichi site.
There are ongoing efforts in support the development of accident tolerant fuels (ATF). Also, we are supporting industry’s development of severe accident water management guidelines to comply with regulatory requirements.
Sponsor
U.S. Nuclear Regulatory Commission, Department of Energy – Nuclear Energy, and Department of Defense
