Initial Measurements of BN-350 Spent Fuel in Dry Storage Casks using the Dual Slab Verification Detector

Year
2010
Author(s)
Richard Williams - Los Alamos National Laboratory
Peter Santi - Los Alamos National Laboratory
M.C. Browne - Los Alamos National Laboratory
Corey Freeman - Los Alamos National Laboratory
Robert F. Parker - Los Alamos National Laboratory
Abstract
The Dual Slab Verification Detector (DSVD) has been developed, built, and characterized by Los Alamos National Laboratory in cooperation with the International Atomic Energy Agency (IAEA) as part of the dry storage safeguards system for the spent fuel from the BN-350 fast reactor. The detector consists of two rows of 3He tubes embedded in a slab of polyethylene which has been designed to be placed on the outer surface of the dry storage cask. By performing DSVD measurements at several different locations around the outer surface of the Dual Use Cask (DUC), a signature “fingerprint” can be established for each DUC based on the neutron flux emanating from inside the dry storage cask. The neutron fingerprint for each individual DUC will be dependent upon the spatial distribution of nuclear material within the cask, thus making it sensitive to the removal of a certain amount of material from the cask. An initial set of DSVD measurements have been performed on the first set of dry storage casks that have been loaded with canisters of spent fuel and moved onto the dry storage pad to both establish an initial fingerprint for these casks as well as to quantify systematic uncertainties associated with these measurements. The results from these measurements will be presented and compared with the expected results that were determined based on MCNPX simulations of the dry storage facility.