Generic reactivity equivalence of PWR fuel in spent fuel storage racks

Generic Reactivity Equivalence provides a way of using licensed Monte Carlo neutronic methods to model the poisonous effects of fission products in the design of spent fuel storage racks. The reduced reactivity state of spent fuel is incorporated by equating spent fuel to a lower enriched fresh fuel. A number of Westinghouse storage rack criticality analyses have employed reactivity equivalence and received NRC approval. However, it is an expensive and time consuming procedure when performed for each iteration of storage rack design. Comparison of data for a number of storage facilities suggests that reactivity equivalence is independent of fuel type and storage rack design. Consequently a study was performed to define one set of data (Generic Reactivity Equivalence)