Plutonium Fast Power Breeder with Oxide Fuel and Blanket Elements

A fuel element consisting of plutonium and uranium oxide in steel tubing and capable of a large fraction of fuel burnup is described. As this fuel element makes possible recovery and refabrication with fewer steps than are required for a metal fuel element, lower recycle costs result. Breeders with fuel and fertile material in both oxide and metallic form were analyzed by the multigroup method on the UNIVAC for the purpose of comparing characteristics. A summary of the calculations is presented. The decrease in the breeding ratio resulting from the replacement of the metal core by oxide is only 0.2, a small effect in a future nuclear power economy where plutonium will have a low value as fuel rather than a high value as weapon material. Use of an oxide blanket may further reduce the breeding ratio by 0.05.An illustrative design is presented which has five atoms of uranium per atom of plutonium in the core and 45% sodium, a breeding ratio of 1.4 and a critical mass of 400 kg. Incremental refueling is assumed to reduce the control range required for 50% burnup of the original fuel loaded.