The radiation-induced microstructure of a cold-worked 316SS flux thimble tube from an operating pressurized water reactor (PWR) was examined. Two irradiated conditions, 33 dpa at 290ºC and 70 dpa at 315ºC were examined by transmission electron microscopy. The original dislocation network had completely disappeared and was replaced by fine dispersions of Frank loops and small nano-cavities at high densities. The latter appear to be bubbles containing high levels of helium and hydrogen. An enhanced distribution of these nano-cavities was found at grain boundaries and may play a role in the increased susceptibility of the irradiated 316SS to intergranular failure of specimens from this tube during post-irradiation slow strain rate testing in PWR water conditions.
Revised: June 23, 2010 |
Published: February 28, 2009
Citation
Edwards D.J., F.A. Garner, S.M. Bruemmer, and P.G. Efsing. 2009.Nano-cavities observed in a 316SS PWR Flux Thimble Tube Irradiated to 33 and 70 dpa.Journal of Nuclear Materials 384, no. 3:249-255.PNNL-SA-63624.