Applicability Evaluation of Candidate Technologies for Nuclear Material Quantification in Fuel Debris at Fukushima Daiichi Nuclear Power Station - Passive Neutron Technique - (Interim Report)

Japan Atomic Energy Agency (JAEA) and Central Research Institute of Electric Power Industry (CRIEPI) have surveyed technologies for nuclear material quantification of fuel debris at Fukushima Daiichi Nuclear Power Station (1F) since 2012 under the collaborative program with United States Department of Energy (DOE). Four research groups in JAEA and CRIEPI have evaluated independently the applicability for four technologies, passive neutron technique, passive gamma technique, active neutron technique and active gamma technique, by simulation and small scale measurement tests. All parties recognized the importance of the characterization study on each candidate technology for establishment of the concept of integrated measurement system that combines several measurement technologies for accurate quantification. For the characterization study, common set of models for fuel debris and canister were developed. In order to perform the characterization study consistent with the other technologies, we evaluated the applicability of the passive neutron technique for nuclear material quantification of fuel debris based on the common set of models for fuel debris and canister. This paper provides the results of applicability evaluation on passive neutron technique for nuclear material quantification in fuel debris at 1F.