Since March 2011, the government has focused on the cost of cleaning up after Fukushima, the worst nuclear disaster since Chernobyl. Now, the bill is coming due for another unbudgeted consequence of that calamity — shutting down the nation's 48 remaining nuclear reactors for costly safety reviews that could see many of them mothballed.

While their reactors have been idled, nuclear plant operators have had to spend around $87 billion to burn replacement fossil fuels. This, in part, explains the utilities' estimated combined losses of around $47 billion as of March, and the $60 billion wiped off their market value.

That pain is beginning to tell.