Development of 316L(N)-IG stainless steel fabrication approaches for ITER divertor and limiter applications

The US has focused on development of a cast and hot-isostatic-pressed (HIP) fabrication approach for an affordable and reliable method for fabricating the stainless steel components of the divertor and limiters for ITER. Initial results with the cast/HIP 316L(N)-IG (ITER Grade) stainless steel fabrication approach are encouraging. Cast/HIP mechanical properties are lower than for wrought, but are adequate for fabrication of the components. Casting a near-net-shape blank saves considerable cost in two ways: (1) from a raw material standpoint, less weight of material is needed, and (2) less machining is necessary to remove the excess material. After the sections are cast, they are subjected to a HIP operation intended to provide improved and consistent mechanical properties, compared to stainless steel castings that have not received the HIP operation. This paper discusses the US progress toward developing and evaluating cast and HIP fabrication methods for limiter and divertor applications.