Release characteristics of cesium from green pellet fabricated with spent fuel under different sintering conditions

The dry process, known as DUPIC(Direct Use of spent PWR fuel in CANDU reactor), for fabricating fuel pellets from spent fuel as recycling technology has been well demonstrated by establishing an optimization process for fuel fabrication through a number of batch processes using typical PWR spent fuel. As considering a strategy for extending the burn-up in LWR fuel, experimental verification for analyzing the effect of spent fuel burn-up on fuel fabrication is necessary in some respects that one of key parameters influencing the fuel fabrication characteristic would amount of fission products contained as impurity elements in spent fuel. A high burn-up spent fuel has a higher amount of fission products compared with typical spent fuel irradiated in about 27,000 MWd/tU. A preliminary study showed that the sintered pellet density fabricated with a high burn-up fuel has a lower value than that of common fuel burn-ups of about 30,000 MWd/tU. To provide better understanding a remote fuel fabrication characteristic in an aspect of wide ranges of spent fuel generated from PWR reactor, the influence of fission products release on fabrication characteristics of the dry processed fuel with a high burn-up fuel of 65,000 MWd/tU were experimentally evaluated. It is expected that key fission product affecting fabrication characteristics in dry process is cesium isotope due to the boiling point of 670 .deg. C and the low dissociation temperature of its oxides(<700 .deg. C). This study focus to analyze the release characteristics of cesium from green pellets fabricated with a variation of compaction pressure under different sintering conditions using tubular furnace in IMEF M6 hot cell