Board Thread:General Discussion/@comment-27779933-20160212001823/@comment-26247132-20160221021916

It was never stated on the show but it was alluded to that Mount Weather was falling apart (as supported by the radiation breaches and their state-of-the-art medical facility just for blood treatments). Basically, even without radiation leaks, they were still getting exposed to small enough amounts of radiation to require weekly maintenance for all 382 of them (hence the number of Grounders they processed through).