Irradiation test of fuel containing minor actinides in the experimental fast reactor Joyo

Soga, Tomonori ; Sekine, Takashi ; Tanaka, Kosuke  ; Kitamura, Ryoichi; Aoyama, Takafumi 

The mixed oxide containing minor actinides (MA-MOX) fuel irradiation program is being conducted using Joyo. Two irradiation experiments were conducted in the MK-III 3rd operational cycle. Six prepared fuel pins included MOX fuel containing americium, MOX fuel containing americium and neptunium, and reference MOX fuel. The first test was conducted with high linear heat rates of 430 W/cm maintained during only 10 minutes in order to confirm whether or not fuel melting occurred. After 10 minutes irradiation in May 2006, the test subassembly was transferred to the hot cell facility and two test pins were replaced with dummy pins. The test subassembly loaded with the remaining four fuel pins was re-irradiated in Joyo for 24 hours in August 2006 to obtain re-distribution data on MA-MOX fuel. Linear heat rates for each pin were calculated using MCNP. Post irradiation examination of these pins to confirm the irradiation behavior of MA-MOX fuel is underway.