Irradiation Test on Swaged UO2 Fuel, (I)

In order to know the in-reactor behavior of swaged UO2 rod developed by Mitsubishi Atomic Power Ind., Inc., the irradiation test of it had been performed with a partial subsidy from Japanese government in 1961. Planning and manufacturing of the irradiation capsule had been done by M. A. P. I. After finishing the irradiation and post-irradiation examination in W. T. R., the specimens were sent back to JAERI's hot cell for the further examination.The irrradiation specimens of cold swaged, hot swaged and sintered pellet fuel rods were assembled in one capsule and irradiated to 8×1020 nvt (2, 700 MWD/T-UO2).The following results were obtained by W. T. R. post-irradiation test concerning visual examination and dimensional change.(1) No appreciable change was observed in the outer appearance of swaged fuel rods.While, the surface of sintered pellet rod was observed to be somewhat oxidized.(2) No dimensional change in swaged rods, but about 0.1 mm swelling in the diameter of sintered pellet rod was found.