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TVA cooling system shutdown.

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This sounds like something that may have been a very short LCO but is getting more press than normal because of Japan. Though an electrical short in a safety system following a valve failure in a safety system does not sound good. Any thoughts or input from our operations types?

The Tennessee Valley Authority, which has touted the safety of its nuclear reactors amid a continuing crisis in Japan, suffered a cooling system shutdown for 40 minutes Thursday after electricity shorted out at a Browns Ferry Nuclear Plant reactor.

The incident came two days after the plant 100 miles south of Nashville was cited by federal authorities with a “red” level violation for a cooling system valve that failed at its Unit 1 reactor.|topnews|text|FRONTPAGE

I read that article on

They have definitely sensationalized the topic.  When I first read it, they stated they lost cooling for over 80 minutes but that figure was a mistake and it was later changed to 40 minutes.

I think the media is trying to find correlation between the violation through the NRC and this incident.

I think one of the comments to that article says it best.

" Reactor water temps rising from 112* to 122* in an idled reactor that normally operates at 300* is like reporting that the sun came up today and reactor temps rose. "

They found somethign that didn't work the way it was supposed to (apparently procedure related) during a functional test. Not something that you like to happen but it does happen. That's why we do PM and testing and have defense in depth.

Lets see if this works  ;D

Here is what was reported to the NRC

Power Reactor Event Number: 46847
Region: 2 State: AL
Unit: [ ] [ ] [3]
RX Type: [1] GE-4,[2] GE-4,[3] GE-4
HQ OPS Officer: JOHN KNOKE  Notification Date: 05/13/2011
Notification Time: 01:53 [ET]
Event Date: 05/12/2011
Event Time: 18:25 [CDT]
Last Update Date: 05/13/2011 
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(B) - POT RHR INOP
 Person (Organization):

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
3 N N 0 Cold Shutdown 0 Cold Shutdown

Event Text


"At 1825 CDT on 05/12/2011, with Browns Ferry Nuclear Plant Unit 3 in Mode 4, Browns Ferry Nuclear Plant PCIS [Primary Containment Isolation System] relay maintenance activities for a Group 1 PCIS relay inadvertently interrupted the neutral for a Group 2 PCIS relay and a Group 2 PCIS isolation occurred resulting in a loss of Shutdown Cooling. Relays were reset and Shutdown Cooling was restored at 1905 CDT. Moderator temperature prior to the event was 112.5 degrees F and the highest moderator temperature recorded during the loss of Shutdown Cooling was 122 degrees F.

"This condition is reportable under 10CFR50.72(b)(3)(v) - Any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to: B.) Remove residual heat.

"This is also reportable as a 60 day written report IAW 10CFR 50.73(a)(2)(v).

"The NRC Resident Inspector has been notified of this event.

"This event was entered into the licensee's Corrective Action Program as SR# 368205".

When I read this my first thought was oh-no not after a degraded cornerstone finding classified as RED.  I think there will be lots of outage work available at the ferry soon.

Honestly I hope it works out for the folks there but does not sound promising to me


Been there, done that. Lots of opportunity to loss SDC at a BWR especially with the amount of common neutrals and daisy chains in the relay schemes.


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