Irradiation damage and IASCC of printed 316L for use as fuel cladding

摘要

Additive manufacturing is an area of increasinginterest to the nuclear industry. It offers a number ofbenefits over traditional manufacturing methods,such as the ability to create complex geometrieswithout the need for welds. In addition to thepotential for creating nuclear structural components,additive manufacturing may be used to create novelfuel/cladding designs. However, printed steelbehaves differently than traditional wroughtmaterial. A number of industries are alreadystudying the effects of the printed microstructures onmechanical properties. For cladding material andsome structural nuclear components, however, thenuclear industry must also understand the materialresponse to irradiation. This work examines theirradiation damage and the irradiation assistedstress corrosion cracking behavior of both protonirradiated (1 and 5 dpa) printed 316L steel andwrought 316L steel that were irradiated side by sideat the Michigan Ion Beam Laboratory. Asorientation with respect to the build direction canaffect the mechanical properties of printed metal,specimens were taken from multiple orientationswithin the printed steel. For the IASCC testing,specimens were strained to 4% in simulated BWRNWC water (288°C, 0.2 μS/cm). TEM, SEM and XraymicroCT were used to examine coupons of thematerial as well as tensile bars used in the IASCCtesting. This work found that the wrought 316L wasmore susceptible to IASCC than the printed steel,however, significant IASCC was observed in theprinted steel when tested with the tensile axis in linewith the build direction. TEM observations haveshown significantly fewer radiation induced voidsforming in the printed steel, likely due to the preexistingvoid network acting as sinks to point defects.The lower density of voids is believed to becontributing to the IASCC resistance by decreasingthe localization of deformation in the irradiatedspecimens.