no surprise the Rac cracked it is 30 years old these were designed for 25 year life.I would suggest that the damned thing is at end of life and now they need to toss it .No easy fix, because it is in a radiation zone and not a service replacement item. you can send welders in, but, the cost is fairly high and you would spend a long time in an outage, at least 2 years and you have to recertify, so maybe