FABRICATION, IRRADIATION TESTING AND POST-IRRADIATION EXAMINATION OF DUPIC FUEL

摘要

A total of about four kg of spent PWR fuel has been processed at AECL into three DUPIC (Direct Use of spent PWR fuel in CANDU~®) fuel elements. The fuel elements have been undergoing irradiation testing in the fuel test loops in the NRU reactor for about two years. One fuel element has been discharged after achieving a burnup of 230 MWh/kg H.E. and has undergone post-irradiation examination (PIE). Initial indications are that the DUPIC fuel generally behaves similar to fresh UO2 fuel irradiated under similar conditions, except that it experiences a greater degree of pellet-centre microstructural change and slightly higher fission gas release. This result is consistent with expectations, given the high total burnup of the fuel material (28 MWd/kg H.E. in a PWR, plus an additional 10 MWd/kg H.E. as DUPIC fuel). This paper describes the fabrication of the DUPIC pellets and elements, the irradiation testing conditions and the PIE results on the world's first DUPIC fuel element.