DEVELOPMENT OF AN ACTIVE WELL COINCIDENCE COUNTER FOR U-AL BILLET ASSAY

Year
1989
Author(s)
Jeffrey C. Griffin - Westinghouse Savannah River Company
Edward R. Selden - Westinghouse Savannah River Company
Edward R. Selden - Westinghouse Savannah River Company
Abstract
The Savannah River Site (SRS) has completed an experimental evaluation of the application of an active well (neutron) coincidence counter (AWCC) to the assay of 235U in U-A1 coextrusion billets of the Savannah River Site fuel fabrication area. Using U-A1 coextrusion core standards for the experimental measurements, the AWCC was tested in several different source/sample configurations. As a result of this work, a new configuration was identified for billet assay. This configuration, using a moderated ArnLi source placed in the central hole of the billet, yielded a twostandard- deviation precision of 0.6-1.0% for a twentyminute assay. This precision is a factor of 2-3 better than that obtained from the operation of the AWCC in the standard configuration, i.e., with the interrogation sources located above and below the billet. A dedicated Billet AWCC, using the new center-source configuration and custom-built to accommodate coextrusion billets, is being acquired for use in the fuel fabrication area of SRS. This paper will present details of the experimental work, as well as a description of the resulting AWCC design.