Neutron activation and radiation damage assessment for W-Ni-Fe tungsten heavy alloys with variable Ni content

Abstract

A challenging issue for the magnetic fusion concept of generating nuclear power is the performance of plasma-facing components, particularly in the divertor within the fusion power plant. Tungsten alloys, such as W-TiC, W-La2O3, etc., are the prime candidate structural materials for advanced He-cooled divertors in next-step devices beyond ITER. In recent years, W-Ni-Fe heavy alloys (WHAs) have emerged as more promising alternatives than the above-mentioned alloys. WHAs exhibit superior fracture toughness and better fabricability. However, Ni raises concerns because it may generate an unsafe level of radioactive waste (radwaste). Given the significant promise of WHAs, neutron activation assessment is critically needed, particularly to determine the limit of Ni that can be employed. This is the main purpose of this study. The assessment is provided for disposal option and for recycling alternative of divertors made of WHAs. Additional calculations are performed to obtain the neutron flux and spectrum, transmutation products, and He/H gas production data for a typical divertor design. These additional data are generated to inform future multiscale simulations of microstructure evolution and radiation damage accumulation in WHAs. Furthermore, estimation of atomic displacement damage dose is presented. In the future, the estimated dose should be compared with the more accurate data from the multiscale simulations and revised accordingly.

Keywords

• Neutron activation
• Radiation damage
• Transmutation products
• H and He gas production
• W-Ni-Fe tungsten heavy alloys
• Tungsten composites