Applying PRA and HRA methods to meet codes and standards requirements for evaluating criticality risk associated with seismic events

Meeting current codes and standards requirements uniquely challenges the analysts tasked with modeling and evaluating the risk associated with potential criticality accidents brought about by seismic events. For example, the seismic vulnerabilities generally evaluated by the probabilistic risk assessment/human reliability assessment (PRA/HRA) analysts when determining the overall safety of a nonreactor nuclear facility operation are not necessarily bounding when viewing the operation from a criticality perspective. This paper presents a case study by which seismic and criticality requirements from US Department of Energy (DOE) directives, orders, and standards for nonreactor nuclear facilities (e.g., waste management and spent fuel storage) can be integrated with PRA and human reliability assessment (HRA) methods to identify seismic hazards/vulnerabilities specific to criticality. The scope of this new method encompasses (1) the potential contribution PRA/HRA can make to identifying and evaluating seismic vulnerabilities with respect to nonreactor nuclear facilities having the potential for criticality accidents; (2) ways to reduce the criticality risk associated with the identified seismic hazards/vulnerabilities; and (3) the importance from a cost-benefit perspective of integrating the PRA/HRA analysis with the associated structural analyses. This paper specifically addresses item (1) of this method. Items (2) and (3) of the method will be addressed inmore » subsequent papers.« less