The Next Generation Safeguards Initiative Spent Fuel (NGSI-SF) Project deployed a non- destructive assay (NDA) Passive Neutron Albedo Reactivity (PNAR) system to measure the heavy-water moderated, light-water cooled Fugen reactor fuel assemblies in June 2013. The NDA system combines the following NDA techniques: ( 1) PNAR, (2) total neutron, (3) total gamma and (4) three sets of fission chambers. Each set of these fission chambers is surrounded by different materials to detect neutrons in differ ent energy ranges. The measurement results of the four NDA techniques included have been analyzed and compared to Monteburns simulations of the Fugen fuel assemblies to assess the measurement capabilities of the PNAR system. Photon measurements matched the photon simu lations performed by the Fugen plant well. PNAR measurements showed a change in the PNAR signal that trended with multiplication. Future plans with this instrument will include measuring a variety of fresh fuel assemblies comprised of differing numbers of low-en riched rods (3.2%, 0.7%, and 0.3% pins, as well as 3.2% pins with Gd) at Los Alamos National Laboratory. These experiments will be performed in water and be driven by neutrons from a Cf source placed inside the assembly.
View of Fugen NPP (Source: Japan Ministry of Land, Infrastructure and Transport)
- J. Eigenbrodt, "Spent Fuel Measurements: Passive Neutron Albedo Reactivity (PNAR) and Photon Signatures", Ph.D. Dissertation, Nuclear Engineering, Texas A&M University, College Station, TX (2016).
- J. Eigenbrodt, S.J. Tobin, W.S. Charlton, A.M. Bolind, H.O. Menlove, M. Seya, H.R. Trellue, "PNAR Measurements of Fugen Fuel", 55th Annual Meeting of the Institute of Nuclear Materials Management, Atlanta, Georgia, 20-14 July 2014.
- J. Eigenbrodt, W. Charlton, H.O. Menlove, S.J. Tobin, M. Seya, H.R. Trellue, A.M. Bolind, "Simulations and Preparation for PNAR Measurements of Fugen Fuel", Proceedings of the 35th ESARDA Annual Meeting, 27-30 May, 2013, Bruges, Belgium.