Arkansas Nuclear One near Russellville is in the process of restarting a reactor after it was shut down on Tuesday. One of the plant's two reactors was manually shut down after Entergy found that part of a system that generates steam for its turbines was malfunctioning. Sarah Millard, a spokeswoman for Arkansas Nuclear One, said "feedwater oscillations" were the problem.
“After that shut down all the equipment required for safe shutdown of the plant operated exactly as it’s designed. And that allowed us to do some investigating…to understand the cause,” she said.
Millard said the she did not have details about the cause of the malfunction. She couldn't say the exact time and date the reactor would return to service because it was “confidential information for our company.”
The Nuclear Regulatory Commission’s website defines feedwater as:
“Water supplied to the reactor pressure vessel in a boiling-water reactor (BWR) or the steam generator in a pressurized-water reactor (PWR)that removes heat from the reactor fuel rods by boiling and becoming steam. The steam becomes the driving force for the plant's turbine generator.”
Victor Dricks, a spokesman for Region IV of the NRC, said in an email that on-site inspectors are monitoring Entergy's response:
"After the reactor shut down Entergy officials filed a four-hour non-emergency notification with the NRC as required by Title 10CFR 50.72(b)(2)(iv)(B)
Our resident inspectors who work at the site each day are monitoring the licensee’s review of the event to ensure that the root cause is properly identified and any corrective actions that are needed are taken. If they have any findings they will be documented in a quarterly inspection report that will be made publicly available," said Dricks.
The NRC is to conduct a major inspection at Arkansas Nuclear One early next year, a result of the agency giving the plant one of the poorest ratings in the nation.