Christmas Scram Catches NRC Eye

Thursday, January 29, 2015 @ 05:01 PM gHale

An emergency shutdown of Entergy’s River Bend nuclear power plant near Baton Rouge, LA, Christmas morning prompted a special inspection by a team of Nuclear Regulatory Commission (NRC) experts.

The plant automatically shut down at 8:37 a.m. Dec. 25 due to the failure of an electrical circuit for a valve controlling one of the turbines that generates electricity, said Mike Bowen, a spokesman for Entergy Nuclear, which oversees all of Entergy’s nuclear plants.

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Bowen said the initial failure of a piece of equipment at the St. Francisville, LA, plant, 24 miles north northwest of Baton Rouge, did not involve the nuclear reactor.

During the “scram,” where control rods insert into the reactor’s fuel core, water levels reached an overly high “Level 8,” or 56 inches, in the vessel, according to a report on the incident filed with the NRC. That resulted in pumps that feed water to the reactor shutting down.

When the water level dropped below 51 inches, workers attempted to restart one of the feed pumps, and it failed to start. Workers then used an alternate pump to take the failed pump’s place, but a water regulating valve failed to open and monitoring equipment indicated the water level in the reactor had dropped to an extremely low 8.1 inches.

Workers then manually aligned another feed water regulating valve and restored the water level to its normal height, the report said.

The plant was operating at 85 percent capacity when the unplanned shutdown occurred.

“The purpose of this special inspection is to better understand the circumstances surrounding the event, determine if there are any generic implications, and review the licensee’s corrective actions to ensure that the cause of the event, including associated equipment problems, have been effectively addressed,” said Marc Dapas, NRC Region IV administrator.

The inspectors will spend about a week at the reactor to evaluate a “root cause analysis” conducted by Entergy employees, maintenance of plant systems and the adequacy of the company’s corrective actions. An inspection report documenting the findings will be available to the public within 45 days of the end of the inspection.

River Bend’s 974 megawatts of electricity ends up used by Entergy Louisiana and Entergy Gulf States. The plant, which employs 675, began commercial operations in June 1986, and its federal license expires in August 2025. The plant was operating at 100 percent capacity Monday.

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