As Atlanta-based Southern Co. pushes forward with plans for new nuclear reactors in Georgia, problems continue with existing reactors in Alabama.

New equipment failures at Plant Farley near Dothan —- two backup generators failed in March —- have pushed the company close to another safety downgrade, the Nuclear Regulatory Commission told Southern in a letter Friday.

The Farley plant is one of three nuclear plants in the country with a "degraded" safety ranking now. The NRC downgraded it last fall based on the company's handling of valve and breaker failures.

The generator failures could push one of Farley's two reactors —- Unit One —- into the next-worse category by fall, the NRC wrote.

Only one other nuclear plant nationally —- Palo Verde in Arizona —- is in that category, which is one ranking shy of the one that will force a reactor to shut down.

Neither last year's downgrade or the possible additional one mean Plant Farley is unsafe, NRC Deputy Regional Administrator Victor McCree said Friday.

Farley is now in the NRC's third safety classification. One of its reactors could drop to the fourth. Only a plant in the fifth ranking is considered unsafe to operate, McCree said.

But each drop in the rankings brings additional scrutiny from the NRC, at company expense.

Jeff Gasser, chief nuclear officer of Southern Nuclear, said the NRC's safety classification was intended to help the agency allocate inspection resources.

He said the company was concentrating on addressing any problems at Farley.

The NRC is poised to do an in-depth inspection in early June. Gasser said the company is ready for it.

"From our perspective, we fixed the issues," he said. "We're ready for them to come look and verify that we have done the right things."

Farley's problems began in April 2006, when a valve in the plant's cooling system stuck during a test.

The valve was part of the safety system that would flood the reactor's core with water in an emergency.

Believing the problem was the result of dirt, plant employees never opened the valve to inspect it.

It stuck again in January 2007. Employees opened it then and found serious corrosion.

The breaker failure happened several months later, as the NRC was completing its evaluation of the valve problem.

Farley's problems came to a head in November. The NRC issued a finding that pushed both Farley reactors into the "degraded" status, kicking off new inspection requirements.

The same day, a plant engineer filed a whistle-blower complaint with the U.S. Department of Labor, saying he had been punished for reporting safety problems.

Southern settled with the engineer in December. The terms are confidential.

The generator failures happened in March. Like the valve and breakers that failed in the fall, the generators are part of the reactor's contingency system. They're there in case the power fails.

Whether Farley will fall further in the rankings depends on upcoming inspections.

But David Lochbaum, a nuclear safety expert at the Union of Concerned Scientists, said Farley's margin for error is now slim.

"They're right at the edge," he said.

He said it wasn't unusual for plants that slip in the NRC rankings to keep slipping.

"One of the things that happens is that more and more NRC [inspectors] show up at your doorstep," he said.

"With more eyes looking, they find more rocks to turn over."

Eventually, the inspectors run out of rocks, he said.

"It's what happened at Palo Verde," he said. "Farley is not unique."

UPDATE

THE STORY SO FAR

> Previously: Regulators lowered the safety rating for Southern Co.'s Plant Farley in Alabama last fall.

> The latest: The NRC wrote the company Friday that Farley could be hit with another downgrade this fall.

> What's next: An in-depth NRC inspection is planned for early June.

 Staff
Map locates Southern Co. Farley Plant near the border of Alabama and Georgia. Inset map shows area of detail relative to Atlanta.