Experimental study of lithium free-surface flow for IFMIF target design

Lithium free-surface flow experiments to verify the design of IFMIF target have been carried out at Osaka University. The present report summarizes experimental results of surface phenomena, and cavitation characteristics of the loop, so as to try to apply these results to design parameters. Waves on the lithium flow surface is similar to that on water, and can be predicted by a linear stability theory. The wave amplitude is measured by an electro-contact probe. Surface roughness on a target nozzle, caused for example by attached chemical compounds and/or wastages by erosion and corrosion, can lead to a significant loss of target flow stability as well as surface wakes. The need of a polishing manipulator or exchange of the nozzle may be anticipated. Cavitation characteristic of the loop was measured by an accelerometer. From the results, a friction factor could be estimated fort he lithium flow.