An analysis of fast reactor fuel performance

A method for predicting the performance of fast reactor fuel is shortly described together with some results. A computer code, LIFE-I developed at ANL, was used as basic tool. It calculates temperature distribution, fuel restructuring, fission gas release rate and plenum pressure. To evaluate the accuracy of the restructure routine of the code, the calculated radii in central voids, columnar grain region and equiaxed grain region were compared with corresponding measured radii. For this purpose, fuel pins of GE F-1 and F-2 groups irradiated in EBR-II upto 2,000 - 50,000 MWD/T were used. The agreement was within +- 25%. The result of comparison is shown by a figure. Based on this comparison, the restructure routine was adjusted, then the performance of JOYO (Japanese fast experimental reactor being built) fuel was predicted. Pellet diameter, linear heat rate and the irradiation time of the fuel are 5.4 mm, 430 w/cm and 300 days, respectively. The results of prediction are shown in a figure. It shows fuel surface temperature, fuel center temperature, F.P. gas release rate and plenum pressure as the functions of irradiation time. (Aoki, K.)