Post irradiation examination of (U,Pu) C and (U,Pu) N fuel for fast reactor; Non-destructive examination result of the fuel pin

not registered ; not registered; not registered  ; Matsumoto, Shinichiro

In order to evaluate irradiation behavior of(U, Pu) C and (U, Pu) N fuel using fast reactor, (U, Pu) C and (U, Pu) N fuel pins were irradiated in JOYO for the fist time in Japan. In this study, one (U, Pu) C fuel pin and two (U, Pu) N fuel pins were irradiated to maximum burn up about 40GWd/t. Post irradiation examination of (U, Pu) C and (U, Pu) N fuel pins started in Fuel Monitoring Facility (FMF) at JNC from October 1999, and it ended in March, 2000. The results of non-destructive post irradiation examination reported in this document. Main results are shown in the following. (1)The soundness of all (U,Pu) C and (U,Pu) N fuel pins were confirmed from the non-destructive examination result. (2)The fuel stack elongation of (U,Pu) C and (U,Pu) N is bigger than it of the MOX fuel for fast reactor. (3)The singular behavior from the gamma ray scanning measurement in the stack area was not confirmed. The migration of Cs137 to lower insulator pellet and outside of the pellet was confirmed in (U,Pu) N B9NO2 pin. In (U,Pu) C fuel, the migration of Cs137 was not confirmed. (4)In (U,Pu) C B9CO1 pin and (U,Pu) N B9NO2 pin in which the gap width was small, diameter of cladding increase around 50 m in the stack area which originates for FCMI was confirmed. In (U,Pu) N B9NO1 pin in which the gap width was wide, the ovality which originates from the relocation of the pellet was confirmed. (5)Fission gas release rate of (U,Pu) N were 3.3% and 5.2%, and the low value compared to the MOX fuel was shown.