Abstract: The nuclear fuel material includes up to 1% of plutonium and the remainder enriched uranium of an enrichment necessary to achieve a desired fissile content. A typical nuclear fuel material includes 0.160% fissile plutonium or 0.216% total plutonium and 99.784 uranium of 3.171 enrichment in uranium 235. This material replaces 100% uranium of 3.30 enrichment. There is also disclosed a nuclear fuel element with the above-described fuel material and a nuclear reactor fueled by such elements.There is further disclosed wet methods of treating spent nuclear fuel wherein the appropriate quantity of enriched uranium to achieve the desired fissile content is added to the solution of uranium and plutonium after separation from the fission products or to the solution of plutonium alone after separation of the plutonium from the uranium.

Abstract: An improved spacer grid for a nuclear fuel assembly comprising fuel rods in a matrix wherein each rod is adapted to be enclosed by a spacer "cell" for positioning thereof relative to adjacent rods in the fuel assembly.