Prairie Island questions safety rating from NRC

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Prairie Island nuclear plant

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RED WING - Questioning a safety rating issued earlier this summer, Prairie Island nuclear plant officials met Thursday with the Nuclear Regulatory Commission to make their case.

Xcel Energy is challenging a preliminary safety rating that classified a battery charger issue as "white," meaning it has low to moderate safety significance. Xcel officials said they believed it should instead be "green" - having very little safety significance.

The NRC characterizes issues on a color scale. Green is the lowest, followed by white. Those posing more serious safety concerns can be tagged with a "yellow" or "red" rating.

The plant's "white" rating stems from an issue discovered in Unit 1's safety-related battery chargers. The chargers were "found to have the potential of not performing their safety functions under certain event scenarios" including a low charge, the NRC said. The charger would "lock up" and stop charging during tests that simulate losing off-site power, inspectors found.

Prairie Island Site Vice President Mark Schimmel had said the finding is based on a condition that existed in the past. The chargers on Unit 1 have been replaced, and those on Unit 2 are slated for replacement during the next refueling outage. Xcel just completed a fuel outage earlier this summer.

"Xcel Energy is committed to operating its nuclear plants safely, and we take this matter very seriously," Schimmel said in a statement after Thursday's meeting. He added, "This condition does not represent any actual failure of plant systems or equipment nor did it pose any threat to the public or plant workers."

The NRC was not set to make any final decisions at the conference, which took place at the agency's Region III office in Illinois. The agency will review the findings and any new information or clarifications from Xcel before ruling on the preliminary safety rating.

The plant, which is looking to increase generating capacity at both of is units, was relicensed in July after a three-year review process. The new licenses for the site's two reactors will expire in 2033 and 2034.

The utility also recently settled lawsuits with the federal government on the issue of storing spent nuclear fuel. The government has agreed to pay Xcel Energy more than $100 million to cover the cost of storing the fuel, and Xcel officials have said the company will pass the reimbursement on to ratepayers.

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