Post-Irradiation Examination of ~(237)Np Targets for ~(238)Pu Production

摘要

Plutonium-238 is used as a heat source in radioisotope thermoelectric generators. In support of the U.S. Department of Energy ~(238)Pu production program, a number of irradiation tests have been performed by the Oak Ridge National Laboratory (ORNL). For one particular test, two arrays—each containing seven neptunium-loaded targets—were irradiated at the Advanced Test Reactor (ATR) in Idaho to examine the influence of multi-target self-shielding on the products. The arrays were located in the same irradiation facility but were axially separated to minimize the influence of one array on the other. After completion of irradiation and shipment back to ORNL, the targets were chemically processed to measure the residual neptunium, total plutonium production, ~(238)Pu production, and ~(236)Pu concentration. The amount and isotopic composition of fission products were also measured. The results of these tests are being used in the design of the ~(238)Pu production process.