Development of recycling processes for clean rejected MOX fuel pellets

• Dry and wet (MWDD) methods were developed for 100% recycling of CRO (0.4–44% PuO2).
• Dry method showed higher productivity and comparable powder/product characteristics.
• MWDD batches demonstrated improved powder/product characteristics to that of virgin.
• Second/multiple recycling is possible with MWDD with better powder/product characteristics.
• MWDD batches prepared by little milling showed better macroscopic homogeneity to that of virgin.

The dry and wet recycling processes have been developed for 100% recycling of Clean Reject Oxide (CRO) generated during the fabrication of MOX fuel, as CRO contains significant amount of plutonium. Plutonium being strategic material need to be circumvented from its proliferation issues related to its storage for long period. It was difficult to recycle CRO containing higher Pu content even with multiple oxidation and reduction steps. The mechanical recycling comprising of jaw crushing and sieving has been coupled with thermal pulverization for recycling CRO with higher Pu content in dry recycling technique. In wet recycling, MicroWave Direct Denitration (MWDD) technique has been developed for 100% recycling of CRO. The powder prepared by dry and wet (MWDD) recycling techniques was characterized by XRD and BET techniques and their effects on the pellets were evaluated. (U,21%Pu)O2 pellets fabricated from virgin powder and MWDD were characterized using optical microscopy and α-autoradiography and the results obtained were compared.