Deformation Microstructures of 30 dpa AISI 304 Stainless Steel after Monotonic Tensile and Constant Load Autoclave Testing

Irradiated AISI 304 stainless steel extracted from the Chooz A center filler assembly has been the subject of a number of studies. Previously the results of slow strain rate tensile and constant load autoclave tests of 30 dpa material have been reported. They showed an influence of temperature, strain rate and environment on the fracture behavior of the material. The irradiated microstructure and deformation micro structures of those materials following testing have now been examined by TEM. The findings suggest that substantial channel deformation was associated with the purely ductile fracture following SSRT testing in argon, while the intergranular fractures following SSRT in simulated PWR environment and constant load testing in both simulated PWR and argon environments were associated with very localized deformation primarily exhibiting alpha martensite. This possibility is discussed in the light of literature.