EXPLOITING THE PLUTONIUM STOCKPILES IN PWRS BY USING INERT MATRIX FUEL

The plutonium coming from dismantled warheads and that already stockpi led coming from spent fuel reprocessing have raised many concerns rela ted to proliferation resistance, environmental safety and economy. The option of disposing of plutonium by fission is one of the most widely discussed and many proposals for plutonium burning in a safe and econ omical manner have been put forward. Due to their diffusion, PWRs appe ar to be the main candidates for the reduction of the plutonium stockp iles. In order to achieve a high plutonium consumption rate, a uranium -free fuel may be conceived, based on the dilution of PuO2 within a ca rrier matrix made of inert oxides. In this paper, a partial loading of inert matrix fuel in a current technology PWR was investigated with 3 -D calculations. The results indicated that this solution has good plu tonium elimination capabilities: commercial PWRs operating in a once-t hrough cycle scheme can transmute more than 98% of the loaded Pu-239 a nd 73 or 81% of the overall initially loaded reactor grade or weapons grade plutonium, respectively. The plutonium still left in the spent f uel was of poor quality and then offered a better proliferation resist ance. Power peaking problems could be faced with the adoption of burna ble absorbers: IFBA seemed to be particularly suitable. In spite of a reduction of the overall plutonium loaded mass by a factor 3.7 or 5.4 depending on its quality, there was no evidence of an increase of the Minor Actinides radiotoxicity after a time period of about 25 years. C opyright (C) 1996 Elsevier Science Ltd