Core damage frequency results for the Clinch River Breeder Reactor

A probabilistic risk assessment (PRA) for the Clinch River Breeder Reactor Plant (CRBRP) was recently completed by Technology for Energy Corporation, Knoxville, Tennessee, for the Department of Energy, Oak Ridge Operations Office. The PRA was performed in two phases with the second phase starting in January 1983. Phase II activities were originally planned to result in a Level 3 PRA with full-scope analysis of the external and common-cause events, as well as ex-core sources. The Phase II activities were cut short because of the termination of the CRBRP Project in November of 1983, at which point the scope of the PRA was changed to the following goals: 1) complete the CRBRP system models; 2) calculate the plant core-damage frequency; 3) study the core and containment phenomena in a probabilistic sense; 4) determine the design features important to plant safety, and therefore important to any considerations of new designs for liquid-metal reactors; and 5) extensively document the PRA to enable its use for other programs. This paper summarizes the frequency of core-damage accidents as assessed by this study. The discussion also includes the important design operational elements of the CRBRP that affect these results. A short overview of the methodology used is also provided