(Changes time frame to late February instead of late January in
By Timothy Gardner
WASHINGTON, March 1 A group of engineers within
the U.S. nuclear power regulator is concerned that a design flaw
in nearly all U.S. nuclear plants could endanger emergency core
cooling systems. The group has urged the regulator to order
power station operators to either fix the problem or face
Seven engineers in late February petitioned the Nuclear
Regulatory Commission to order immediate enforcement actions
against licensees of U.S. nuclear power plants, in a
little-noticed, but public move.
The petition, filed under a standard NRC process, urges the
agency to respond by March 21.
The engineers are concerned that a design flaw in nearly all
U.S. nuclear facilities leaves them vulnerable to so-called open
phase events in which an unbalanced voltage, such as an
electrical short, could cause motors to burn out and reduce the
ability of a reactor's emergency cooling system to function. If
the motors are burned out, backup electricity systems would be
of little help, the petition said.
In early 2012 an unbalanced voltage event forced Exelon
Corp's Byron 2 reactor in Illinois to shut down
automatically. The unit was shut for about a week.
Later that year, the NRC alerted nuclear power plant
operators in a bulletin to a potential design vulnerability
concerning open phase and collected feedback from the operators.
But the agency never ordered the plants to make changes to
reduce any open phase vulnerabilities. The petition said 13 open
phase events have occurred at U.S. and international nuclear
plants over the last 14 years.
Dave Lochbaum, a nuclear expert at nonprofit group the Union
of Concerned Scientists, said it was encouraging that the
engineers stepped forward without fear of retribution. But he
said those concerns show "something is not right with the safety
culture at the agency." The NRC could have eased concerns years
ago by forcing plants to take action, he said.
"Why the NRC snatched defeat from the jaws of victory, I
don't know," Lochbaum said.
The nuclear industry played down the petition. "This is not
a matter of safety significance that merited interruption of the
safe operations of our facilities, in 2012 or now," said John
Keeley, a spokesman at the Nuclear Energy Institute.
Scott Burnell, an NRC spokesman, said the engineers'
petition "will be considered under our normal process." Based on
responses to the bulletin the agency issued in 2012, the NRC is
"confident that plants are safe to continue operating," Burnell
(Editing by Matthew Lewis)