Abstract
Liquid mercury target system for high power spallation neutron sources is being developed. When high intensity proton beams are inj ected into the target, pressure waves are generated by the thermal shock in mercury and pitting damage will be imposed on the target vessel. Bubble injection into mercury is effective to mitigate the pressure waves, In this work, we propose a method of fabricating mesa-nozzle for bubbles inj ection. The method is based on powder metallurgy by inserting thin glass fibers into a metal powder matrix to create a green compact, followed by sintering at a temperature between the melting points of the powder and the fiber. SUS316L and molybdenum powders were used as the nozzle matrix materials. In order to investigate optimum sintering condition, experiments were performed at different combinations of pressing load and sintering temperature. We found that a pressing load of 392MPa and sintering temperature of 1875℃ for molybdenum provide high relative density and straight hole with circular cross section.
