PHOENIX — The margin of safety at the nation's largest nuclear power plant has narrowed but the problems don't pose a threat to the public, according to federal regulators.
The Nuclear Regulatory Commission has increased oversight at the Palo Verde Nuclear Generating Station outside Phoenix since March, spending 8,500 hours on the project.
During a meeting at the triple-reactor plant Wednesday night, the commission said it found 37 more-than-minor performance deficiencies affecting operations.
Most of the problems cited involved laxness in procedures, incomplete documentation, and inefficient problem-solving efforts.
There has been a notable decline in Palo Verde's performance since 2003, said Troy Pruett, chief of the reactor-projects division of the NRC, who led the investigation.
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But Pruett added that the team determined the plant is operating safely even though it has seen degradation in safety performance.
Officials with Arizona Public Service Co., the plant's operator, said they are addressing safety at Palo Verde.
Pruett said inspectors twice witnessed managers ignoring signs announcing required radiological monitoring. The managers walked past stations intended to test for contamination.
Investigators also found combustible material stored in a nuclear-containment dome without proper documentation, Pruett said.
Palo Verde, the nation's largest nuclear power plant both in size and capacity, has been on the regulatory hot seat in recent years over a series of problems that have included generator failure.
Located in Wintersburg about 50 miles west of downtown Phoenix, the plant supplies electricity to about 4 million customers in Arizona, New Mexico, Texas and California.
