S.J. Tobin, W.S. Charlton, M.H. Ehinger, M.L. Fensin, A.S. Hoover, H.O. Menlove, B.J. Quiter, A. Rajasingam, N.P. Soval, S.F. Saavedra, D. Strohmeyer, M.T. Swinhoe, S.J. Thompson, “Determining Plutonium in Spent Fuel with Nondestructive Assay Techniques”, Proceedings of 31st Annual Meeting of ESARDA, May 26-28, 2009, Vilnius, Lithuania.
There are a variety of motivations for quantifying plutonium in used (spent) fuel assemblies by means of nondestructive assayincluding the following: shipper/receiver difference, input accountability at reprocessing facilities and burnup credit at repositories or fuel storage facilities. Twelve NDA techniques were identified that provide information about the composition of an assembly. Unfortunately, none of these techniques is capable of determining the Pu mass in an assembly on its own. However, it is expected that the Pu mass can be quantified by combining a few of the techniques. Determining which techniques to combine and estimating the expected performance of such a system is the purpose of the research effort recently begun. The research presented here is a complimentarily experimental effort. This paper will focus on experimental results of one of the twelve non-destructive assay techniques – passive neutron albedo reactivity. The passive neutron albedo reactivity techniques work by changing the multiplication the pin experiences between two separate measurements. Since a single spent fuel pin has very little multiplication, this is a challenging measurement situation for the technique. Singles and Doubles neutron count rate were measured at Oak Ridge National Laboratory for three different burnup pins to test the capability of the passive neutron albedo reactivity technique.