PNNL

Abstract

A challenging issue for the magnetic fusion concept is the performance of plasma facing components, particularly the divertor. Tungsten alloys are the prime candidate structural materials for divertors of next-step devices beyond ITER. Material experts developed several W alloys (such as W-TiC, W-La2O3, W-Re, etc.) for advanced He-cooled divertors that can handle heat fluxes beyond 10 MW/m2. In recent years, W-Ni-Fe heavy alloys (WHAs) emerged as a promising alternative for divertor applications. WHAs offer good fabricability and remarkable fracture toughness. However, the Ni raises concerns on radwaste and production of He and H gases that may be significant enough to impact the thermo-mechanical properties. In response, this paper addresses the Ni activation issue for a wide range of 2-9 wt.% Ni content in WHAs and suggests alternative approaches to alleviate the radwaste disposal limitations. Furthermore, essential neutron flux and spectrum, transmutation products, and He/H gas production data are generated for a typical divertor design to help future studies in assessing the primary-knock-on atom recoil spectrum, atomic displacement per atom, and radiation damage accumulation in different microstructural regions of the alloys. As such, we generate separate activation data to distinguish the He, H, and transmutation products that come from W, Ni, and Fe separately at the front and back regions of the divertor.