An Assessment of Clinch River Breeder Reactor Core Disruptive Accident Energetics

A methodology is developed for the evaluation of the energetic consequences of postulated core disruptive accidents (CDAs), in liquid-metal fast breeder reactors. The methodology provides a framework for integrating the results of mechanistic analyses, including whole-core simulations (SAS, SIMMER), special effects analytical evaluations, and simulant material experiments into a probabilistic appreciation of accident evolution paths and respective likelihoods. Detailed quantitative results are presented for the Clinch River Breeder Reactor heterogeneous core design. As a result of this work, new perspectives were generated in the following areas: role of plenum fission gases, presence and role of small recriticalities in the early stages of core disruption, large annular and cylindrical pool recriticalities and associated disassembly yields, energy partition, and the role of structural response of vessel internal structures. The results indicate that a CDA-induced energetic vessel head failure is physically unreasonable.