PLUTONIUM BURNING IN PRESSURIZED-WATER REACTORS VIA NONFERTILE MATRICES

The plutonium that comes from dismantled warheads and that is already stockpiled from commercial fuel reprocessing has raised many proposals for its burning in a safe and economical manner. The utilization is e xamined of current pressurized water reactors (PWRs) that are partiall y fed with a nonfertile oxide-type fuel, while the rest of the core is still fed with standard U-235-enriched fuel. The unconventional fuel consists of PuO2 diluted in an inert matrix, which should be highly ra diation resistant, scarcely neutron absorbent, and chemically stable a nd which allows the final disposal of the discharged fuel without any treatment. Commercial PWRs operating in a once-through cycle scheme ca n transmute 97 to 99% of Pu-239 and 71 to 84% of total initially loade d reactor- and weapons-grade plutonium, respectively. The remnant plut onium is in a proliferation-resistant condition. The high initial reac tivity of the plutonium-bearing rods causes a high initial rod power p eak and continuously decreasing power generation in these rods during the irradiation. A less pronounced rod power peak in UO2 rods at end o f life has to be addressed. The reactivity coefficients are, in absolu te terms, slightly lower than the standard UO2 fuel ones.