Safety Relief System Design for the DALS Test Facility Cryogenic System

A new project called Dalian Advanced Light Source (DALS) is proposed by the Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences (CAS) and is subject to Chinese central government’s approval. To test SRF cavities and accelerator cryomodules, a series of test benches, including horizontal test bench (HTB), vertical test cryostat (VTC), injector test bench (ITB) and cryogenic test bench (CTB), are under construction in Dalian, China. The dedicated test facility cryoplant (TFCP) will provide cooling power for test benches through the test facility distribution box (TFDB). The cooling capacity of the TFCP is 370W@2 K. Amongst those key issues for the entire system, like reliability, efficiency, process arrangement as well as auxiliary design, top priority has been given to the safety relief system. Such a system shall be able to handle emergency scenarios include but not limited to degradation or sudden loss of vacuum, runaway fill, pipe rupture and rapid energy dissipation in cold helium. In this paper, safety relief solutions for DALS test facility cryogenic system have been introduced and evaluated. Sudden loss of vacuum to air will be viewed as the worst case during the sizing phase, to deter the niobium cavities from danger of over-design pressure, there also equips a decompression system for safety relief.