Investigation of fast and cost-effective partial defect detector for spent fuel transfer verification to enhance nuclear safeguards

• A partial defect detector design proposed for spent fuel inspection before transfer from storage pool to difficult-to-access storage facility. • Performance indicator of a detector applied to the spent fuel inspection was quantitatively analyzed from a regulatory standpoint. • Detection capability of new design was assessed with the randomly distributed fuel defect scenarios. The current nuclear safeguards approach to spent nuclear fuel inspection at nuclear power stations is based on item counting and limited partial defect analysis. With the expected surge in spent fuel storage, limited spent fuel storage pool capacity, and the increasing need for transferring fuel to long-term storage facilities, there is a growing demand for more efficient and cost-effective nuclear safeguards approaches for nuclear materials management in civilian nuclear power facilities. This study proposes a scintillator-based indirect gamma detector for spent fuel inventory screening inspection, specifically designed for use in interim storage pools prior to fuel transfer to difficult-to-access storage. This paper presents the design of the proposed detector, its application for spent fuel screening inventory inspection, and analysis using MCNP for partial defect detection. Results of analysis indicated that verifying a ∼ 13.6 % level of randomly distributed fuel defect for the Westinghouse 17x17 fuel assembly is possible using this approach. The performance evaluation also indicates that inspection of spent fuel assemblies of various vendor types against 1 SQ diversion may be possible.