Kobayashi Tooru, Miura Kuniaki, Hayashizaki Noriyosu, Aritomi Masanori
Kyoto University Research Reactor Institute, Osaka 590-0494, Japan; Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan.
Sukegawa Electric Co., Ltd., Ibaraki 317-0051, Japan.
Appl Radiat Isot. 2014 Jun;88:198-202. doi: 10.1016/j.apradiso.2013.12.013. Epub 2013 Dec 19.
A feasibility study on liquid lithium target in the form of a flowing film was performed to evaluate its potential use as a neutron generation target of (7)Li(p,n)(7)Be reaction in BNCT. The target is a windowless-type flowing film on a concave wall. Its configuration was adapted for a proton beam which is 30mm in diameter and with energy and current of up to 3MeV and 20mA, respectively. The flowing film of liquid lithium was 0.6mm in thickness, 50mm in width and 50mm in length. The shapes of the nozzle and concave back wall, which create a stable flowing film jet, were decided based on water experiments. A lithium hydrodynamic experiment was performed to observe the stability of liquid lithium flow behavior. The flowing film of liquid lithium was found to be feasible at temperatures below the liquid lithium boiling saturation of 342°C at the surface pressure of 1×10(-3)Pa. Using a proto-type liquid lithium-circulating loop for BNCT, the stability of the film flow was confirmed for velocities up to 30m/s at 220°C and 250°C in vacuum at a pressure lower than 10(-3) Pa. It is expected that for practical use, a flowing liquid lithium target of a windowless type can solve the problem of radiation damage and target cooling.
对流动薄膜形式的液态锂靶进行了可行性研究，以评估其作为硼中子俘获疗法（BNCT）中（7）Li（p，n）（7）Be反应的中子产生靶的潜在用途。该靶是凹壁上的无窗型流动薄膜。其结构适用于直径为30mm、能量高达3MeV、电流高达20mA的质子束。液态锂的流动薄膜厚度为0.6mm，宽度为50mm，长度为50mm。基于水实验确定了产生稳定流动薄膜射流的喷嘴和凹形后壁的形状。进行了锂流体动力学实验，以观察液态锂流动行为的稳定性。发现在表面压力为1×10（-3）Pa时，液态锂的流动薄膜在低于342°C的液态锂沸腾饱和度的温度下是可行的。使用用于BNCT的原型液态锂循环回路，在低于10（-3）Pa的真空度下，在220°C和250°C时，对于高达30m/s的速度，确认了薄膜流动的稳定性。预计对于实际应用，无窗型流动液态锂靶可以解决辐射损伤和靶冷却问题。
