Mercury flow experiments, 4; Measurements of erosion rate caused by mercury flow

Kinoshita, Hidetaka; Kaminaga, Masanori; Haga, Katsuhiro; Hino, Ryutaro

JAERI-Tech 2002-052, 28 Pages, 2002/06

JAERI-Tech-2002-052.pdf:7.59MB

Since the Neutron Scattering Facility will be using mercury as the target material and contain radioactive products, it is necessary to estimate reliability of instruments in a system. The system would be damaged by erosion. An erosion test section and coupons were installed in the mercury loop, and their thickness was measured. As a result, the erosion is about 3m in 1000 hours under 0.7m/s condition. The wall thickness decrease during facility lifetime of 30 years is estimated to be less than 0.5mm. Therfore, the effect of erosion on component strength is extremely small. Moreover, a measurement of residual mercury on the piping surface was carried out. As a result, 19g/m was obtained. Thus, estimation of residual mercury for 150A-sch80 piping is 8.5g/m, and for the mercury target is about 40g. As for the target, radioactivity of the residual mercury is 1.210 Bq, which is extremely lower than that in the target casing of 1.010 Bq. Then, there is no influence for maintenance and storage of the spent mercury target.