Production of Plutonium-238 with Minimum Plutonium-236 Contamination

Abstract

Small-scale test irradiations of ²³⁷Np in the Richland and Savannah River production reactors have provided substantial empirical information on the mechanisms for formation of ²³⁶Pu. Application of this information to the design of larger scale irradiations in the Savannah River high flux reactor has resulted in successful production of 2 kg of ²³⁸Pu, meeting current isotopic specifications for the heart program. Further work is planned to develop practical technology of producing still larger amounts. The optimum location for target ²³⁷Np in the D₂O reflector of the high flux charge has been established. Tests have demonstrated that matrix material for the targets is an important variable, and that the use of aluminum should be avoided. Irradiations of kilogram quantities of ²⁴¹ Am have been completed and most of the resulting ²⁴²Cm will be allowed to decay into ²³⁸Pu before chemical processing (about two years). However, small amounts of the irradiated ²⁴¹Am will be processed promptly to provide ²⁴²Cm for decay into ultra-high purity ²³⁸Pu.