Determining Plutonium Mass in Spent Fuel Using 252Cf Interrogation with Prompt Neutron Detection

252 Cf Interrogation with Prompt Neutron (CIPN) detection is proposed as one of 14 NDA techniques to determine Pu mass in spent fuel assemblies (FAs). CIPN is a relatively low-cost and portable instrument, and it looks like a modi?ed fork detector combined with an active interrogation source. Fission chambers (FCs) were chosen as the neutron detectors because of their insensitivity to ? radiation. The CIPN assay comprises two measurements, a background count and an active count, without and with the 252 Cf source next to the fuel respectively. The net signal above background is primarily due to the multiplication of Cf source neutrons caused by the ?ssile content. The capability of CIPN to detect diversion and to determine ?ssile content was quanti?ed using MCNPX simulations. New schemes were proposed (such as burnup and cooling time correction, etc.) and the results show that the ?ssile content of a target spent fuel assembly can be determined using CIPN signal.