Just crap
The super conducting alloys might need cooling but not not down to 0 kelvin more like 200 kelvin and it will be kept at 180 which leaves a safety gap of 20 degrees a small piece bread would not increase heat atall. The reason for the heat increase was a plumbing failure which might for been caused by some from the future but much more likely to be simple mistake made while fitting the hundreds of miles of pipe work.