中子慢化器低温及真空性能测试系统设计

中子慢化器低温及真空性能测试系统,用于验证中国散裂中子源氢慢化器的低温性能和真空密封性。此套系统由供液系统、气体加热系统、流量控制系统、温度与压力监测系统组成,采用液氮替代液氢作为测试介质,通过加热器对液氮直接加热的方式获得低温氮气。每根输液管道都是独立的真空单元,配有真空抽口,采用双层不锈钢管道,管道之间做绝热处理。通过控制加热器与内管的装配精度来保证气体换热效率。使用Lakeshore Model 336温控仪和TELEDYNE HASTINGS流量控制器进行气体温度和流量调节。该系统气体输出温度精度达到±5 K,气体输出流量约500 L/min±10%。此套系统不仅为大型低温系统提供安全可靠的低温测试工作介质,同时节约了实验成本,将来在航空航天领域能得以应用推广。

Self-Developed Test Platform for Evaluation of Operation Conditions of Neutron Moderator

A novel test platform was developed for evaluation of the cryogenic,vacuum and sealing conditions of the neutron moderator and hydrogen moderator for China Spallation Neutron Source.The self-developed test platform comprised the liquid-nitrogen supply,heating of gas unit,flow-rate controller,monitoring of temperature subunit,and pressure alarm subunit. The red-copper resistive heaters turn liquid nitrogen into cold gas(80~100 K); and the cryogenic pipelines were thermally insulated. The test platform was used to evaluate the coupled/decoupled posioned hydrogen moderators. The results show that the test platform meets all the stringent design requirements. For example,it is capable of providing cryogenic nitrogen-gas at a flow-rate up to 500 L/min with a tolerance of 10% and a gas temperature control precision of 5±K. We suggest that the test platform be of some technological interest in testing large-sized vacuum and/or cryogenic equipment.