Domestic nuclear plants significantly reduced their power level, or were forced offline, more than 40 times between August 2007 and August 2015 in connection with either severe weather events or temperature changes at the plant’s cooling water source.
That’s according to information that the Nuclear Regulatory Commission (NRC) provided to Sen. Edward Markey (D-Mass.) in December.
In October 2015 Markey had requested that NRC provide him with information on the effects of extreme weather, higher water temperatures and climate change on nuclear power plants over the past decade.
The weather-related changes in reactor operational status ranged from less than 30 minutes to more than a month, according to the NRC data.
“In compiling a list of power reactor shutdowns and power reductions, NRC staff searched through events that were required to be reported to the NRC and also met the conditions described in your request,” NRC Chairman Stephen Burns said in a Dec. 10 letter to Markey.
The NRC chairman also noted that the Federal Energy Regulatory Commission (FERC), as the federal agency responsible for monitoring grid reliability, would also have data on power plant changes induced by weather effects, Burns said in the letter.
One of the enclosures provided to Markey shows that events affecting nuclear plant performance included tornados, hurricanes, flooding, winter storms and various cold or icing events.
“In addition to a list of shutdowns and power reductions, you also requested a list of requests for permission to increase the water intake temperature, as well as the NRC’s justifications for approving or denying those requests,” Burns said in the letter.
NRC requires nuclear plants to have an “ultimate heat sink (UHS), which is a source of cooling water that is available under both normal and accident conditions, to remove heat from the nuclear station. “It is the temperature of this UHS that limits the ability of the facility to remove heat from the plant,” Burns said in the letter.
During his career in Congress, Markey has been a frequent critic of the nuclear energy industry and NRC.