Public Affairs Officer
The NRC requires U.S. nuclear power plants to be able to shut down safely in the face of many extreme events – tornados, hurricanes and earthquakes. But the NRC also takes into account far more unusual events, like solar flares and man-made electromagnetic pulse (EMP). Both can affect generators, transformers and other parts of the electric grid – which in turn could affect nuclear power plants.
The NRC has been examining these issues for more than 30 years, starting in the late 1970s when the agency studied how EMP could affect nuclear power plant safe-shutdown systems. In February 1983 the NRC issued the study’s conclusion: nuclear power plants’ safety systems can do their jobs after an EMP event. The agency revisited the issue in 2007 to account for the increasing use of digital computer systems in nuclear plants, which potentially could be more susceptible to EMP. The agency continued to conclude as recently as two years ago that nuclear power plants can safely shut down following an EMP event.
The NRC has also examined “solar storms” and their potential to damage the electric grid. A strong geomagnetic storm on March 13, 1989, for example, severely disrupted electrical power equipment in Canada, Scandinavia, and the United States. After studying the event the NRC issued an Information Notice in June 1990, to ensure nuclear power plants understood how severe solar activity could affect transmission systems and other components of the power grid.
Additional research in 2010 analyzed and compared solar or geomagnetically-induced current events to those of the EMP events previously analyzed. This work led to the same conclusion as the EMP studies – U.S. nuclear power plants can safely shut down if a solar storm disrupts the grid.
The edge of the NRC’s authority lies in a nuclear power plant’s electric switchyard, where our rules mesh with those of the Federal Energy Regulatory Commission, which oversees the nation’s electric grids. Another body, the North American Electric Reliability Corporation develops and enforces grid reliability standards. The NRC works closely with FERC and NERC on grid reliability issues, including the effects of solar or geomagnetic storms and EMP. In 2015 FERC began the process of creating reliability standards to protect the grid against these events.
In 2011 a citizen petitioned the NRC to revisit the issue of grid disruption. The petition discussed ensuring U.S. nuclear power plants have emergency systems to keep spent fuel pools cool for two years after an electric grid failure. The NRC’s draft rule on maintaining key plant safety functions after a severe event, issued last year, includes measures to keep spent fuel pools cool.
The NRC is also participating in a White House-led task force on better understanding and dealing with space weather such as solar flares. Much of this work aims to improve society’s ability to forecast and warn against these events. Both the Department of Energy and electric grid companies have started efforts to stockpile specialized electrical equipment (such as large transformers) needed to restore the grid after these events.
The original blog post ran in October 2011.