The Preparation of Multigram Quantities of Curium-242 for SNAP-11

SNAP-11 is an isotope-fueled thermoelectric generator, fueled with 7.5 g of ²⁴²Cm, which was obtained from ²⁴¹Am irradiated to ∼1.2 × 10²¹ n/cm². The irradiated material was dissolved in hydrochloric acid 15 to 30 days after discharge from the reactor and processed through two cycles of solvent extraction to remove ionic and radioactive contaminants. The curium and americium were converted to the sesquioxide, pelletized, and encapsulated into the isotopic heat source. The heat source was installed in a thermoelectric converter package to complete the SNAP-11 system, which was then tested for 90 days in a lunar environment simulator at a pressure of 10⁻⁷ Torr and temperatures from −235 to +235°F. It successfully met all performance specifications.