[fbdab103]

I do not work with MRIs, but I work next to the guys who run the NMRs (which is the ~same technology). It is my understanding that all of these super cooled magnets are designed for the eventuality of an emergency quench. Which means the machine has a direct path to evacuate the gas, and it should be piped into the building's HVAC so that if a quench does happen, the people in the area do not suffocate because of lack of oxygen.

A surprising amount of maintenance can occur while the magnets are cold and energized. My armchair-uniformed-guess is that they can replace the not-always-working relief path without venting.