Evaluation of lrradiation performance in Monju-type fuel subassembly (MFA-1)

Donomae, Takako; ; ; Akasaka, Naoaki; Yamagata, Ichiro; ;

JNC TN9400 2000-075, 374 Pages, 1999/08

JNC-TN9400-2000-075.pdf:18.85MB

The irradiation test of the Monju-type fuel subassembly, MEA-1, was conducted at FFTF as a Joint Research Program of Fuels and Materials between DOE and PNC. MFA-1 subassembly is consisted of cladding tube, wrapper tube, wrapping wire which are all made of PNC316, as well as 85% low density pellet. The pellet peak burnup and maximum fast neutron fluence reached 147.1GWd/t and 21.410n/m, respectively. Based on the results of Post-irradiation examination, Subassembly and fuel elements behaviors have been evaluated, and the following results were obtained. (1)The wrapper tube elongation and dilation are relatively small, and the fuel pin diameter changes were measured to be about 4% in maximum. The Bundle-Duct lnteraction (BDI) was confirmed not to be severe condition in Monju-type fuel assembly up to the fast neutron fluence of 21.410n/m. (2)In the claddings with the sand-brusted treatment to shave the flaw on the inner surface, the enhanced sweIling was measured, compared with PNC316 claddings manufactured by the usual process. lt is considered that this swelling enhancement in sand-brusted claddings attributed to relatively higher level of residual stress and lower cold-worked. (3)The deferent temperature dependency in swelling was evaluated for cladding and wrapping wire: the peak swelling temperature to be 495C for cladding and 475C for wrapping wire. 0n the contrary, the swelling-temperature dependency for wrapper tube was not able to be determined.