Speaker
Description
The sudden loss of insulating vacuum is a potentially severe event to be considered in the safety analysis of cryogenic applications. When insulating vacuum is broken, large heat fluxes can heat up and expand cryogenic fluids inside the vacuum-insulated apparatus in a very short time.
The effect is particularly pronounced in applications involving helium, hydrogen and neon at temperatures below the condensation temperature of air, where air condensation on the cold surfaces leads to instantaneous peak heat fluxes that have been reported to be on the order of tens of kilowatts per square meter in some cases.
The effect is currently being investigated at several institutions worldwide. However the incorporation of the vacuum loss scenario into the safety design, and particularly the sizing of relief devices of cryogenic apparatus based on existing norms and standards, is not immediately obvious. We take a look at existing norms and present a way forward which we consider to be prudent and appropriate.
