Post-cold war nuclear weapons demilitarization is expected to yield tonnes of fissile material which must be destroyed rapidly to assure complete unrecoverable weapon demilitarization. An effective, efficient, and economical method of destroying this fissile material is to mix it with spent nuclear fuel that has been reprocessed by the AIROX (Atomics International Reduction Oxidation) method [AIROX Dry Reprocessing of Uranium Oxide Fuels, DOE Research and Development Report, Rockwell International, Report No. ESD-DOE-13276]. The mixture can then be transmuted in light water reactors (LWRs) with concurrent electric power generation.
To form a suitable powder for fabrication of high-quality LWR oxide fuel ceramic-pellets, the feed (i.e., fuel) material must be well-mixed, finely divided, and reactive under pressing and sintering conditions. Therefore, the enrichment material prepared from demilitarization of nuclear-weapons must also be very finely-divided reactive PuO.sub.2 powder.
In order for the fissile plutonium (Pu) to form an enrichment material for AIROXed spent fuel, however, it must be converted to a fine (&lt;200 mesh) reactive plutonium oxide (PuO.sub.2) powder. Normally plutonium metal is converted to PuO.sub.2 powder by slow combustion. This does not, however, necessarily produce a fine reactive powder and can produce very unreactive (e.g., high-fired) oxide. High fired oxide (i.e., oxide heated at 550.degree. C. for over an hour) is very unreaetive, forms poor-quality LWR oxide fuel pellets, and could easily be separated from the PuO.sub.2 already in AIROXed spent fuel even after mixing by simple dissolution of the AIROXed produced PuO.sub.2 in 2N HNO.sub.3 (PUREX) process.
Fissile, high-fired PuO.sub.2 will not dissolve in 2N HNO.sub.3. AIROXed PuO.sub.2 is easily dissolved in 2N HNO.sub.3. Therefore, a method is needed which renders weapons grade plutonium to a form which is (1) reactive for fuel fabrication and (2) readily dissolves in 2N HNO.sub.3.