Pacific Northwest Laboratory Report on Fusion Energy Research, April 1977 - June 1977

The development of economic data for fusion power plants continued in a study estimating the potential impact of a shortage of materials important in fusion plant construction. In studies developing heat transfer and fluid flow design tools for fusion reactor blankets, preconceptual design studies were initiated to identify the potential design limits of water cooling in the first wall of Tokamak Next Step (TNS) concepts. In surface effects research clean gold samples were irradiated in the University of California (D,Be) neutron source for a neutron sputtering experiment. Light ion and neutron irradiation experiments have continued in studies of the effects of radiation on mechanical properties. The hardening response of 14 MeV neutron-irradiated nickel changed at high particle fluences (10/sup 16/ to 10/sup 17/ particles/cm/sup 2/) while the hardening response of 16 MeV proton-irradiated nickel did not, which may have been due to a difference in irradiation hardening mechanisms. The flux dependence of the damage microstructure and irradiation hardening of materials needs further study to clarify uncertainty about light ion and fusion neutron damage processes. Neutron irradiations of Ni, 316SS, and Nb wires and foils were completed. Work has continued in studies developing acoustic emission (AE) techniques for determining the prebreakdown behavior and failure mechanisms in electric insulators with potential applications in fusion reactors. Scoping experiments with the high-vacuum dielectric breakdown apparatus were conducted