Friday, July 05, 2019

Nuclear Power, Once Seen as Impervious to Climate Change, Threatened by Heat Waves

By Alan Neuhauser, Staff Writer July 1, 2019, at 3:02 p.m.

Harnessing the enormous power of nuclear fission, plants generate steam, which shoots through pipes to spin a turbine that generates massive amounts of electricity. To keep from getting dangerously hot, the plants suck up surrounding water from the nearby rivers, lakes or oceans around which they're built to cool the steam.

Now, increasingly, more frequent heat waves and hotter average temperatures are making those waters so warm that engineers are concerned that it can't do the job. Analysts say climate change is to blame.

In little-noticed but publicly available reports to regulators, nuclear plant owners revealed that unusually hot temperatures last year forced them to reduce the plants' electricity output more than 30 times – most often in the summer, when demand from nuclear plants is at its highest. In 2012, such incidents occurred at least 60 times. At one plant in Connecticut a reactor was taken offline for nearly two weeks when temperatures in the Long Island Sound surged past 75 degrees.

The incidents, submitted to the Nuclear Regulatory Commission, reflect a sharp uptick from even a decade ago, when plants appear to have submitted only nine such reports in 2009. In 1988, 1989 and 1991, there was just one such report. The dramatic increase mirrors the rise in average U.S. and global temperatures spurred by climate change.


And even when water temperatures only approach those thresholds, plants can still be forced to dial down their output if the water used to cool their reactors will cause the temperatures in surrounding waterways to rise so much that it will endanger the habitats of fish and plants.

Limerick Generating Station outside Philadelphia, for example, reported turning down its output 79 times between 2008 and 2016.


Climbing temperatures are not the first climate impact to strike nuclear power plants: The sector has also faced challenges from periodic but increasingly frequent droughts that can cause local water sources to run low.

And it's not just water temperatures that plants have to contend with. Air temperatures can also cause conditions inside the plant to get too hot to operate. So desperate was a power plant in France during last year's heat wave that it began spraying water on the outside of the building to keep the interior from overheating. Plants in the U.S., meanwhile, have regularly slashed their output by anywhere from 3% to 60%.


Unlike other power sources such as gas, oil and coal, increasing and decreasing the output from a nuclear plant puts considerable strain on the facility – forcing earlier and more frequent maintenance expenses in a cash-strapped industry.

"Ramping plants is terrible for them, because nuclear plants don't respond well to the changes in stresses. It's a big deal to ramp up and down," Kammen says. "It's definitely not ideal for the long-term: The only way a nuclear plant ever makes money is if they operate for the long-term with low maintenance costs."


"For every 10 degrees that the temperature goes up, the lifetime of the electrical equipment is reduced quite a bit. Some of your safety equipment may then just fry," Lochbaum says.

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