Millstone’s Unit 2 nuclear reactor was shut down for 12 days after the water temperature in Long Island Sound rose above 75 degrees, which regulators deem too warm to properly cool the reactor.
That was the first time the water in Long Island Sound was measured to be that warm, Millstone Spokesman Ken Holt said in a previous interview with Patch. Now, Dominion, owner of Millstone, is asking the Nuclear Regulatory Commission (NRC) to allow it to use warmer water to cool its reactors, according to the Associated Press.
Meanwhile the head of the NRC has asked for a review of climate change impacts on nuclear plants nationwide, according to the AP. This was the first time since Millstone opened in 1970 that the water in Long Island Sound hit temperatures above 75 degrees, a temperature buoyed by a warm winter, Holt said in a previous interview with Patch.
Millstone uses water from Long Island Sound to cool its two reactors. The NRC's regulations, which were established several decades ago, state that water used to cool reactors must be below 75 degrees.
The Unit 3 reactor takes in deeper water, which is colder, and therefore was able to stay open in August. But Unit 2 takes water closer to the surface, and that water was deemed too warm to cool the reactor by the NRC.
Now Millstone must provide “a lot of calculations” showing that the reactors could be cooled with water above 75 degrees, AP reports, but other power plants in the country use water warmer than 75 degrees to cool their reactors.
The warm water temperature was attributed to a warm winter last year, along with a hot summer. The winter is much colder this year, however, and so is the water in Long Island Sound.