Experiments on mercury circulation system for spallation neutron target

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

A construction of the spallation neutron source is being promoted under the Japan Proton Accelerator Research Complex (J-PARC) Project. A mercury circulation system has been designed to supply mercury to the target stably. It was necessary to make clear a mercury pump performance, erosion rate under the mercury flowing condition and an amount of remaining mercury after draining from the viewpoints of evaluating lifetime of piping and establishing remote handling scenario of mercury components. The mercury pump performance, the erosion rates and the amount of remained mercury were investigated by using a mercury experimental loop with an experimental gear pump. The discharged flow rates of the experimental gear pump are sufficient and it is increased linearly with the rotation speed. Erosion rates were found to be so small that decrease of piping wall thickness would be estimated 660 m after 30-year operation under the rated velocity of 0.7 m/s. For the amount of remaining mercury, remaining rates of weight was estimated at 50.7 g/m.