Scott Burnell
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.