North Anna Nuclear Power Plant: A Closer Look
Much of the concern of a possible nuclear disaster following the Virginia earthquake was quelled this morning when Dominion Power Company ended the alert at its North Anna Nuclear Power Plant in Mineral, Va., at 11:16 a.m. EST.
“The reactors were cooled by natural circulation and emergency pumps while the reactor coolant pumps were not operating,” it announced.
The site remains in a Notification of Unusual Event (NOUE) category, the least serious of four Nuclear Regulatory Commission (NRC) emergency classifications.
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Twelve other nuclear plants in Virginia, Maryland, Pennsylvania, New Jersey, North Carolina and Michigan were placed in the "unusual events," category. This includes Calvert Cliffs, the closest plant to Washington, D.C., just 50 miles from the city limits.
North Anna is located just a few miles from the epicenter of Tuesday’s earthquake that shook the East Coast, which is why it was the hardest hit. Anna lost power after the quake, immediately stopping operations. This caused four diesel generators to kick in and keep the plant running safely, according to Scott Burnell, spokesperson for the Nuclear Regulatory Commission (NRC).
The backup generators prevent reactors from overheating and potentially melting during emergency shutdowns. One of the backup generators, however, had a leak, according to the NRC incident report. A fifth one was then brought in to help cool.
Dominion released a statement saying that there was no release of radioactive material exceeding those that are typical during normal operations.
“Things are under control. There’s no appreciable damage. The operators are continuing to examine the plant in more detail to make sure they aren’t missing anything.”
Japan’s Fukushima power plant caused major health issues when it was hit by a 9.0-magnitude earthquake and tsunami in March. The failure of back-up generators to cool the system was the main culprit to the partial meltdown the plant experienced. In light of Tuesday’s earthquake, many people feared that U.S. nuclear plants are not properly equipped to handle natural disasters.
People also feared that because the plant was in the East, it would not be structurally built to withstand an earthquake as strong as the one on Tuesday, which was magnitude 5.8.
"An earthquake in our area is very unusual," said Nianhong Chen, a visiting lecturer in University of Maryland Eastern Shore's Department of Natural Sciences, according to the Star Democrat. "Earthquakes are caused by movement in the crust, and on the East Coast we don't have a very active tectonic process. This type of earthquake is not generated by active tectonic boundaries. It's caused by a fault."
After the Fukushima disaster that caused high toxic levels in water and other major health concerns, the U.S. launched a readiness program, called Near Term Task Force, to ensure that the nuclear plants in this country would not cause widespread safety concerns if a natural disaster were to occur.
The Nuclear Energy Institute ensures in a press statement that the nuclear facilities are “required by law to develop and regularly test comprehensive on-site and off-site emergency response plans.” The NRC and each respective state reviews and regularly tests these plans with the aid of police, firemen, and other emergency personnel. The communication between different levels of government is “crucial to preparing for possible emergencies.”
According to Power Engineering Magazine, the Near Term report concluded a similar chain of events that happened in Japan was “unlikely” to happen in the U.S. However, it did propose 12 safety recommendations in the areas of loss of electrical power, earthquakes, flooding spent fuel pools and preparedness. The NRC told its staff it had until October 3 to determine which of the task force’s recommendations to implement first.
Massachusetts Rep. Edward Markey, the top Democrat in the House Natural Resources Committee and a senior member of the Energy and Commerce Committee, said in an August 24 letter to NRC Chairman Gregory Jaczko that the Virginia earthquake is a sign the Task Force recommendations need to be implemented sooner.
“The Virginia earthquake is now our local 911 call to stop delaying the implementation of stricter safety standards,” Markey said.
Having emergency diesel generators and secondary battery generators onsite “is not sufficient,” according to Markey. He called on the NRC to enforce maintenance requirements to ensure that the generators operate as intended.
According to Power Engineering, a report that Markey released in May, there were 74 reports of emergency diesel generator inoperability at 33 nuclear plants in the past eight years, including the one at North Anna, despite warnings from the NRC in 1989 and 2007.
“The station was safe during the event. We are just doing investigations to find out why it would lose power. There is no damage,” said Jim Norvelle, spokesperson for Dominion, implying that the shutdown was more of a safety precaution than the result of harmful destruction.
“All U.S. nuclear power stations are built to withstand the most historic natural disaster that occurred in its geographic location. Anna was built for 6.2 Richter event.”
Burnell points out to The Wall Street Journal that, in fact, the soil part of the site is built to withstand a 6.2 magnitude quake. However, North Anna is built partially on soil and rock. The rocky part can only withstand up to a 5.9 magnitude.
The plant is likely to have "extra margins built into the design," Burnell said, according to the WSJ. So "the real-world performance" could be better than those levels.
The analysis of North Anna, which is ongoing, will also determine whether the ground motion the plant experienced Tuesday exceeded the levels it was built to withstand. Burnell told The Christian Post that the NRC requires nuclear plants to be able to withstand a certain amount of ground motion, known as ground acceleration.
These requirements are specific to each nuclear plant and measure the point at which a plant can safely shut down. At this point, they do not have enough information to determine what the ground acceleration was on Tuesday.
Norvelle maintained, “The power station did exactly what it was supposed to.”
No other East Coast plant had operations disrupted.
