This is not what the U.S. nuclear industry needed.

We now appear to be running out of an essential compound needed to cool fission in the most common type of nuclear generator, according to a General Accounting Office report.

The news comes as American utilities will have mothballed at least five nuclear power plants in 2013 due to lower natural gas prices and runaway operation costs.

Lithium-7 is used to filter out acidity and contaminants in a pressured water nuclear plant's coolant. Here's the diagram.

We used to produce our own lithium-7.

But doing so is really bad for workers' health, so we stopped in the '60s.

Since then we've basically relied on the Russians and the Chinese to supply us. They harvest it as a byproduct from making nuclear weapons.

But according to GAO, we now barely have enough lithium-7 to meet our current demand, and definitely not enough to add more nuclear generating capacity if we ever wanted to.

"...little is known about the lithium-7 production capabilities of China and Russia and whether they will be able to provide future supplies. China and Russia produce lithium-7 as a by-product of enriching lithium-6 for their nuclear weapons programs, according to a DOE official, much like the United States previously did. Because of the secrecy of their weapons programs, China and Russia’s lithium-7 production capabilities are not fully known, according to lithium-7 brokers."

And the supply risk out of both countries is only going to increase.

China will need to begin keeping its own lithium-7 for the 25 new nuclear plants its scheduled to open by 2015.

And a lithium-7 broker to GAO staff that for reasons that remain unclear, he was now having trouble finding Russian manufacturers.

The agency outlines three options to address the situation: start aggressively sourcing and stockpiling lithium-7, restarting domestic production of it, or start transitioning reactors away from it. The first one would be resisted by whatever manufacturers are left as it would tank prices, and the other two would be insanely expensive.

So the bottom line is this: "The risk of relying on so few producers of lithium-7 leaves the 65 pressurized water reactors in the United States vulnerable to supply disruptions."