E Hitachi told nuclear operators to conduct tests to determine what conditions would prevent the reactors from shutting safely during an earth quake.
It warned operators of boiling water reactors worldwide that the plants could fail to shut automatically during an earthquake, potentially risking the safety of the power plant.
The affected plants are of the same GE design as Japan's Fukushima reactors which were crippled by an earthquake and tsunami in March.
GE said the probability of a reactor not shutting properly is very low. Because of the limited circumstances under which a unit might not shut automatically, NRC spokesman Scott Burnell said the issue "is not an immediate safety issue."
Affected by the potential glitch are type 2-5 BWRs designed by General Electric and built between the late 1960s and the early 1990s.
GE Hitachi spokesman Michael Tetuan said most nuclear plants could fix the problem by replacing fuel channels, if needed. A typical boiling water reactor has between 400 and 800 such channels.
GE Hitachi identified the problem in July 2010 and reported to the NRC last September, months before an earthquake-spawned tsunami crippled GE reactors in Japan.
"We've proactively identified a very unique set of conditions in which a plant rarely operates where this is a concern," Tetuan said. "With the guidance provided to our customers, they will be able to monitor potentially affected fuel channels and avoid a safety concern."
Tetuan said the company also notified operators of BWRs located elsewhere.
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