Safety assessment and design of pressure relief plate for 2K cryostat to test SCRF cavities

Pressure relief device protects process equipment from the hazards of high pressure. The purpose of relief valve sizing is to determine the proper discharge area of the device. This also includes size of the associated inlet and outlet piping. Calculations were performed to determine the size of the relief systems; so that the helium gas can escape in event of catastrophic vaporization of the liquid helium. The pressure build up has to remain within the acceptable limit. Two independent relief systems are incorporated i.e. rupture disc and plate type valve. Mass flow rates through these devices have been calculated for different set of temperatures and pressures. Pressure build up under different catastrophic scenarios such as loss of insulation vacuum, in case of fire and leakage of liquid helium inside the vacuum space are simulated and discussed in the paper. Considering the worst case pressure and temperature, the overall flow rate has been found to be safe with a factor of safety in excess of two. (author)