Post Irradiation Examination for The FUGEN High Burn-up MOX Fuel Assembly (III) Final Report

Ikusawa,Yoshihisa   ; Kikuchi, Keiichi ; Ozawa, Takayuki   ; Nakazawa, Hiroaki; Isozaki,Takao*; Nagayama, Masahiro*

The E09 fuel assembly was irradiated in the FUGEN from February 1990 to January 1997. The fuel assembly was the highest burn-up assembly in FUGEN and the pellet peak burn-up reached about 48 GWd/t. The E09 fuel assembly was transported to Japan Atomic Energy Research Institute (JAERI) Tokai in 2001. Post Irradiation Examinations (PIE) were started in July 2001, and all PIE items were completed by March 2005. The irradiation behavior of E09 MOX fuel was evaluated from the result of PIE. The major results are as follows; The integrity of E09 fuel assembly and fuel rods was confirmed. The corrosion behavior of ATR MOX fuel cladding was similar to that of LWR-UO2 fuel cladding. The central void was observed in outer ring samples irradiated with the maximum linear power over 45kW/m. A porous fine structure, similar to the rim structure seen in LWR-UO pellet, was observed in the circumferential region of MOX pellet and around the plutonium-rich spots. The MOX fuel properties irradiated up to ~48 GWd/t, which are pellet swelling, thermal conductivity, pellet melting temperature and diffusivity of fission gas, were similar to LWR-UO fuel properties. These results will be used for CANDU-OPTION program, which is one of Russian surplus weapon plutonium disposition programs with AECL in Canada, and available for LWR plutonium recycle program in Japan.