The Uranium Cylinder Assay System for Enrichment Plant Safeguards

Year
2010
Author(s)
Tomonori Iwamoto - Japan Nuclear Fuel Limited
Howard O. Menlove - Los Alamos National Laboratory
Martyn T. Swinhoe - Los Alamos National Laboratory
J. B. Marlow - Los Alamos National Laboratory
Carlos D. Rael - Los Alamos National Laboratory
Karen A. Miller - Los Alamos National Laboratory
Takayuki Tamura - Japan Nuclear Fuel Limited
Syun Aiuchi - Japan Nuclear Fuel Limited
Abstract
Safeguarding sensitive fuel cycle technology such as uranium enrichment is a critical component in preventing the spread of nuclear weapons. A useful tool for the nuclear materials accountancy of such a plant would be an instrument that measured the uranium content of UF6 cylinders. The Uranium Cylinder Assay System (UCAS) was designed for Japan Nuclear Fuel Limited (JNFL) for use in the Rokkasho Enrichment Plant in Japan for this purpose. It uses total neutron counting to determine uranium mass in UF6 cylinders given a known enrichment. This paper describes the design of UCAS, which includes features to allow for unattended operation. It can be used on 30B and 48Y cylinders to measure depleted, natural, and enriched uranium. It can also be used to assess the amount of uranium in decommissioned equipment and waste containers. Experimental measurements have been carried out in the laboratory and these are in good agreement with the Monte Carlo modeling results.