Initial phase of Pu-238 production in Idaho National Laboratory

The initial phase of Plutonium-238 (Pu-238) production for radioisotope thermal generation is described here in detail. Two dosimeters with/without cadmium sleeve containing Neptunium-237 (Np-237) and other neutron sensors were inserted into the low power Advanced Test Reactor Critical (ATRC) for Pu-238 production testing. The gamma-ray energy measurements from Np-238, the short-lived intermediate product, confirmed that sizable amount of Pu-238 can be produced in the full power Advanced Test Reactor (ATR). The Pu-238 production determined from the irradiation experiment was in accord with the modelling predictions. Detailed studies of the Au/Cu sensors for thermal and epithermal flux analysis and their consistency for sensors in different locations, bare and in Cd-sleeve, provided confidence in the Pu-238 production data.