Establishing ITER-Grade Properties in CuCrZr: The Indian Experience

In high heat flux components of neutral beam injector (NBI) systems, CuCrZr alloy is used as a heat sink material. In different national standards, chromium content varies from 0.4 to 1.5 wt%, and zirconium content varies from 0.03 to 0.25 wt%. Indian CuCrZr material was produced at the Non-Ferrous Materials Technology Development Centre and used for the NBI system of the Indian tokomak SST-1, which complied with these chemical composition ranges. The properties of the Indian CuCrZr material were in accordance with procurement specifications. CuCrZr ITER-grade (IG) specifications are as defined in “ITER Materials Properties Handbook” (MPH). The MPH recommends a narrower range of Cr and Zr contents. The reason for limiting the Cr content is that a high Cr content may result in the formation of coarse Cr precipitates, which affect the radiation resistance. Indian CuCrZr with ITER specifications has been produced in a large number (38) of heats and characterized for compositional, tensile, grain size, and weld properties. The properties are, in general, found to comply with those of ITER specifications. The material-processing and component-making steps have been determined, and prototypes of heat transfer elements have been made. Residual ion dump plates have been successfully deep drilled, and component welding trials are in progress. This paper discusses experiences in producing CuCrZr IG and making the elements.