HEAD-END PROCESS FOR THE REPROCESSING OF HTGR SPENT FUEL

摘要

The HTGR spent fuel has a special structure compared with LWR spent fuel. The main difference comes from the head-end process of reprocessing. Recently, some work on the head-end has been done in China. First, the electrochemical method with nitrate salt as electrolyte was studied to disintegrate the graphite matrix from HTGR fuel elements and release the coated fuel particles, to provide an option for the head-end technology of reprocessing. The results show that the graphite matrix can be effectively separated from the coated particle without any damage to the SiC layer. Secondly, the microwave-assisted heating was applied to dissolve the UO_2 kernel from the crashed coated fuel particles. The ceramic UO_2 as the solute has a good ability to absorb the microwave energy. The results of UO_2 kernel dissolution from crushed coated particles by microwave heating show that the total dissolution percentage of UO_2 is more than 99.99% after 3 times cross-flow dissolution with the following parameters: 8mol/L HNO_3, temperature 100 °C, initial ratio of solid to liquid 1.2g/mL.