Proliferation risks, radiotoxicity, environmental safety and energy conservation reasons suggest to burn excess Pu in existing world-wide available LWRs.Inert matrix fuel is a non-fertile oxide fuel consisting of PuO2, either weapon-grade or reactor-grade, diluted in inert oxides such as stabilized ZrO2. Its primary advantage consists in no-production of new plutonium during irradiation, because it does not contain uranium (U-free fuel). Some thoria addition in the matrix (thoria-doped fuel) may be required for coping with reactivity feedback needs. The full thoria-plutonia fuel though still a U-free variant cannot be defined non-fertile any more because the U-233 generation. The advantage of such a fuel option resides in a remarkable already existing technological background and a potential acceleration in getting rid of the Pu stocks. All U-free fuels are envisaged to be operated under a once-throug cycle scheme (the spent fuel is supposed to be sent directly to the final disposal in deep geological formations without requiring any further reprocessing treatment).Calculations show that IMF allows an almost complete burning of fissile plutonium, thus eliminating any proliferation concern. However whole core loading is not feasible, then the yearly amount of burnt plutonium is limited. On the other hand thoria-plutonia fuels have lower capability of plutonium burning, alleviated by the possibility to accept a whole core loading. Some proliferation concerns still exist.An R&D activity for fuel validation is in progress in Italy, in view of an irradiation testing in Halden Reactor and/or a russian PWR. Fabrication test on simulated fuels via GSP process are in progress. Corrosion tests confirmed the high chemical stability of these materials. A new method for thermal parameters measurement has been set up and thoroughly tested.
|Titolo:||Inert Matrix and Thoria Fuels for Plutonium Burning in LWRs|
|Data di pubblicazione:||21-ott-1998|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|