Instrument and controls technicians performing some of the many procedurally required calibrations required before start up of the Unit 1 reactor at the Browns Ferry Nuclear Plant near Athens, Ala.

Browns Ferry Nuclear Plant in Athens, Ala., is shown from above.

Nearly two years after federal regulators red flagged the Browns Ferry Nuclear Plant for safety violations following a critical valve failure, the Tennessee Valley Authority says it has fixed the problems that led to its worst nuclear citation.

TVA Nuclear Chief Preston Swafford said Thursday he expects to submit a letter to the U.S. Nuclear Regulatory Commission in the next few days asking for a review of Browns Ferry and the equipment and procedural improvements made at the North Alabama plant.

"We've been working over two years preparing for this, and I think we've done a good job to try to address the issues we and the NRC have identified," Swafford said. "We've completed everything we were expected to do. We did not request this review until we were ready."

The NRC inspection procedure, known as a 95003 review, is one of the most intense reviews the commission conducts of a plant. In the past decade, there have been only five red flagged nuclear plants and the Browns Ferry citation is the first red flag ever for TVA.

In October 2010, a valve on piece of safety equipment on Unit 1 at the Browns Ferry plant failed to open when operators shut down the reactor for refueling. TVA later determined that the last time the valve definitely had worked as required was in March 2009.

The malfunction, and TVA's inability to detect the problem for so long, led regulators to order an enhanced review of the plant's safety systems and procedures. Potentially, the stuck valve could have impaired TVA's ability to shut down the unit in some accident scenarios.

The valve problem came 26 years after the same Browns Ferry unit suffered from an electrical fire that ignited when a worker was using a candle to check for air leaks.

Since NRC issued a red flag for Browns Ferry in early 2011, TVA has replaced equipment, revamped procedures, upgraded training and performed root-cause analyses to identify problems that led to the equipment and management problems at Browns Ferry. Swafford said TVA spent more than $80 million to bring the plant in compliance with heightened fire safety rules for the first time.

"We have spent a lot of time and effort at Browns Ferry getting ready for the 95003 inspection," TVA CEO Bill Johnson said. "I think we are ready. We expect (NRC inspectors) to come in the next few months and we will be ready when they get there."

NRC spokesman Joey Ledford said a 21-person team from the NRC will conduct the review, which is expected to begin in April and last through much of the spring.

"This is about as an extensive review as a plant gets," Ledford said.