Application of nondestructive assay to the plutonium fuel fabrication facility

Several nondestructive assay methods being utilized or developed for measuring uranium and plutonium at the fuel processing facility of PNC are shortly reviewed. These methods are intended to be used for accounting nuclear materials or for the quality control in the fuel fabrication. (1) The passive gamma assay is being utilized to the quantitative determination of plutonium amount in a fuel pin and to measure the plutonium adhered on various wastes. (2) The passive neutron assay is adopted for the determination of the total plutonium contained in the subassembly of JOYO. (3) An active neutron assay system with Cf-252 as a neutron source has recently been installed, and the measurement of the fissile isotope contents of plutonium and uranium is expected. (4) An X-ray fluorescence equipment is being used to deal with numerous analysis samples coming from fuel fabrication process. It is expected to serve as a quick analysis method for the process control of the solution or powder of uranium or plutonium. (5) A calorimeter is under test run, and is expected to be of high accuracy, though it takes long time in measurement. (Aoki, K.)