Development of the Versatile Test Reactor Probabilistic Risk Assessment

The Versatile Test Reactor (VTR) is a fast spectrum test reactor currently being developed in the United States under the direction of the U.S. Department of Energy (DOE), Office of Nuclear Energy (DOE-NE). The mission of the VTR is to enable accelerated testing of advanced reactor fuels and materials required for advanced reactor technologies. The conceptual design of the 300-MW(thermal), sodium-cooled, metallic-fueled, pool-type fast reactor has been led by U.S. national laboratories in collaboration with General Electric-Hitachi and Bechtel National Inc. To facilitate risk-informed design and authorization activities during the conceptual development phase, a conceptual design probabilistic risk assessment (PRA) was performed for the VTR. This paper provides an overview of the development of the VTR conceptual design PRA, including key DOE and industry standards and the PRA analysis approach and structure. In addition, the results of the VTR conceptual design PRA are provided, which include its use within authorization documentation and design decisions, along with important lessons learned during the process. The work reported in the paper is the result of studies supporting a VTR conceptual design, cost, and schedule estimate for DOE-NE to make a decision on procurement. As such, it is preliminary.