Wiscasset cask leaks? (Score 1)

The article stated, without explanation, that the casks emit radiation into the air. Can anyone provide more information about these incidents? Thanks. From the article: --"..which retains a small staff to maintain its 64 casks of radioactive waste, each of which weighs more than 300,000 pounds, emits temperatures of up to 114 degrees, and releases small amounts of radiation into the air. .."