The U.S. Nuclear Regulatory Commission is ending stepped-up inspections at the nation’s largest nuclear power plant complex because of improvements made by the plant’s operator, the agency announced Tuesday.
The action also boosts the plant’s safety rating from the lowest on the NRC’s ranking system to the top, said Victor Dricks, a commission spokesman.
The triple-reactor Palo Verde Nuclear Generating Station 50 miles west of Phoenix has been under heightened scrutiny since 2004. That’s when federal inspectors found that plant operator Arizona Public Service Co. had left air pockets in portions of the emergency core cooling system at all three reactors.
More problems followed, and in 2006 the NRC lowered the plant’s safety rating to the lowest of any U.S. plant.
“They’ve fulfilled all the requirements and we’ve seen substantial improvement, so we’re reducing our oversight accordingly, but maintaining our vigilance,” Dricks said.
Palo Verde supplies electricity to about 4 million customers in Arizona, New Mexico, Texas and California. It is run by APS for a consortium of power companies in the four states.
Teams of federal inspectors have done five comprehensive inspections at the plant in the past year to ensure that APS was implementing its plan to improve operations. Earlier this year, 10 inspectors from all four NRC regional offices spent two weeks at the plant.
Besides the dry emergency cooling system found in 2004, inspectors later found leaky oil seals in reactor coolant pumps, a broken backup diesel generator and heat exchangers that cool emergency equipment and spent fuel storage areas that were fouled by years of plant technicians using an improper chemical mix.
An APS spokesman said the decision by the NRC was important for the company. “The people at the plant have worked very, very hard and that work has paid off, but they understand that the work is not done and it is an ongoing mission,” spokesman Jim McDonald said.