Diverse active well neutron coincidence counter utility at the Savannah River National Laboratory

Abstract

In this paper we describe use of the Aquila active well neutron coincidence counter for nuclear material assays of 235U in multiple analytical techniques at Savannah River Site (SRS), at the Savannah River National Laboratory (SRNL), and at Argonne West National Laboratory (AWNL). The uses include as a portable passive neutron counter for field measurements searching for evidence of 252Cf deposits and storage; as a portable active neutron counter using an external activation source for field measurements searching for trace 235U deposits and holdup; for verification measurements of U-Al reactor fuel elements; for verification measurements of uranium metal; and for verification measurements of process waste of impure uranium in a challenging cement matrix. The wide variety of uses described demonstrate utility of the technique for neutron coincidence verification measurements over the dynamic ranges of 100–5000 g for U metal, 200–1300 g for U-Al, and 8–35 g for process waste. In addition to demonstrating use of the instrument in both the passive and active modes, we also demonstrate its use in both the fast and thermal neutron modes.