Microstructure and elemental distribution of americium-containing uranium plutonium mixed oxide fuel under a short-term irradiation test in a fast reactor

Tanaka, Kosuke  ; Miwa, Shuhei  ; Sato, Isamu; Hirosawa, Takashi  ; Obayashi, Hiroshi ; Koyama, Shinichi  ; Yoshimochi, Hiroshi; Tanaka, Kenya

In order to confirm the effect of americium addition on irradiation behavior of MOX fuel, the "Am-1" program is being conducted in Joyo. The Am-1 program consists of two short-term irradiation tests and a steady-state irradiation test. The short-term irradiation tests were successfully completed and the post irradiation examinations are in progress. This paper reports on the results of PIEs for Am-containing MOX fuel irradiated for 10 minutes. MOX fuel pellets containing 3% or 5% Am were fabricated in a shielded air-tight hot cell using a remote handling technique. The oxygen to metal ratio (O/M) of these fuel pellets was 1.98. They were irradiated at peak linear heating rate of about 43 kW/m. The ceramography results showed that structural changes such as lenticular voids and a central void occurred early, within the brief 10 minutes of irradiation. The results of EPMA revealed that Am migrated to the radial center of the fuel pellet up the temperature gradient.