Neutron Irradiation Creep at 100°C on 316L, AMCR, and Welded 316L Stainless Steel Alloys

Abstract

We performed measurements on the elongation of many different austentic stainless steel alloys irradiating at 100°C in a low flux channel of the High Flux Reactor at Petten varying the applied stress between zero and 300 MPa. We irradiated in total 98 samples in two irradiation rigs. Of these samples only 26 samples could be tested up to a dose of 2.1 dpa, and 13 samples up to a dose of 0.21 dpa. The steels tested are listed in Table I. In the second irradiation rig four TIG-welded samples and one EB-welded sample were irradiated. We found that the length of the samples increased up to an irradiation dose of 0.11 dpa and then either decreased or increased slightly depending on the magnitude of the applied stress. We attributed the increase in length to the volume change due to the formation of carbides and to the accommodation of carbides to the applied stress. The decrease of the length with irradiation time is attributed to the formation of brittle α-ferrite. The amount of α-ferrite formed increases with decreasing irradiation temperature and increases with decreasing applied stress. Eight samples broke during irradiation in 8 columns or stems in two rigs before the first elongation test at 0.11 or 0.21 dpa could be performed. Irradiation of 343 samples of the same materials in the last fifteen years at temperatures between 300 and 500°C did not cause fracture.

Linear variable differential transformer (LVDT)-based elongation measurements in Advanced Test Reactor high temperature irradiation testing

“…As discussed in [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] have deployed creep test rigs to detect the growth of tensile and creep specimens using a bellows to apply a variable load to a specimen and LVDTs to detect the growth of the specimen. In table 1, we compare aspects of these various creep test setups.…”