Internal review on the state of loss of vacuum research on helium cryogenic systems

It is commonplace in helium cryogenic systems to utilize vacuum insulation to mitigate convective heat transfer to the low temperature fluids. While the insulating vacuum meaningfully improves cryogenic system thermal performance, failure of the insulating vacuum results in rapid heat transfer to the cryogenic helium often resulting in loss of fluids from venting, potential over-pressure of the system, and risks damage to vessels and equipment. The nature of the loss of vacuum problem is highly transient and difficult to predict uniformly across applications, although several efforts have incurred in recent decades to evaluate the heat transfer mechanism and develop useful models.