Nuke plant unit offline after power disruption

Published 3:56 pm Monday, March 11, 2019

A Notice of Unusual Event was declared by the Tennessee Valley Authority Saturday after an external source powering Unit 3 at Browns Ferry Nuclear Plant was lost, causing the reactor to shut down.

The incident did not pose a risk to the plant or public, but a NOUE was filed with the Nuclear Regulatory Commission because the off-site power loss lasted longer than 15 minutes. The notice was declared at 11:12 p.m. Saturday and ended at 1:10 p.m. Sunday.

A NOUE is the lowest of four Nuclear Regulatory Commission classifications for a nuclear event.

TVA Spokeswoman Melinda Hunter said the unit shut down after the power loss and the backup diesel generators automatically started. The off-site power was eventually restored, but Unit 3 won’t be restarted until the cause of the outage has been determined.

“TVA nuclear personnel are working to safely return the unit to service,” she said.

The loss of Unit 3 means only one reactor, Unit 1, is functional at the nuke plant. Unit 2 is also down for a scheduled refueling outage.

Despite only having one reactor working, Hunter said customers should not be affected because of TVA’s energy diversity, which includes coal and hydroelectric sources.

She said the Unit 3 reactor “remains stable” and Unit 1 is unaffected.

“Operators performed as trained, systems operated as designed and there was no safety impact to employees or the public. An investigation is under way to determine the cause.”