Recommendations for measurement systems for nuclear material accountancy of Fukushima Daiichi fuel debris; technologies

Tomikawa, Hirofumi; Heinberg, C.; Nauchi, Yasushi*; Vo, D.*; Carroll, C.*; Hori, Keiichiro

In order to survey technologies to be developed for nuclear material quantification of fuel debris at 1F, Japan Atomic Energy Agency (JAEA) and United States Department of Energy (DOE) started collaborative research from November 2012. Under the collaborative research, three Working Groups, Neutron Working Group (NWG), Gamma Working Group (GWG) and Source Term Working Group (STWG) were established. The roles of GWG are to identify measurement systems that could be studied further for possible implementation at 1F. Candidate measurement technologies are Gross Counting, Dosimetry, -ray Spectroscopy, -ray Densitometry, -ray Imaging, Transmission (X-ray) Radiography, Prompt Fission -ray Counting and Spectroscopy, and Neutron Induced -ray Spectroscopy. Taking into account system cost, system size, measurement time, development period, and potential for applicability to fuel debris, GWG members have identified recommended combinations among the technologies supplemented with neutron measurement technologies. The evaluation was carried out by literature search and simulation works. This paper provides recommendations of the GWG for measurement systems based on mainly measurement technologies for nuclear material accountancy of fuel debris at 1F.