Tuesday, May 08, 2018

Junk Plant Callaway Safety Analysis and Procedures

This could have turned a terrible accident into meltdown. One has no assurance there is no similar issues throughout the industry.  

This is my version of the engineers screwing the control room people. Can you believe this went unaddressed since initial startup? If the licensee can't do their jobs then it is up to the NRC to catch these flaws. Why didn't the CDBI or other special engineering inspection catch them on this years ago? Give them a big fine for not catching it.

Believe me, if you have the big one up in the control room, you are going to all be alone up in the control room. And you know it!!! The NRC and licensees set you up for failure.  
Power Reactor Event Number: 53388
Facility: CALLAWAY
Region: 4 State: MO
Unit: [1] [ ] [ ]
RX Type: [1] W-4-LP
NRC Notified By: JEREMY MORTON
HQ OPS Officer: DAN LIVERMORE
Notification Date: 05/07/2018
Notification Time: 16:31 [ET]
Event Date: 05/07/2018
Event Time: 13:35 [CDT]
Last Update Date: 05/07/2018
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(A) - POT UNABLE TO SAFE SD
50.72(b)(3)(v)(B) - POT RHR INOP
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Person (Organization):
MARK HAIRE (R4DO)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N Y 100 Power Operation 100 Power Operation

Event Text

DISCOVERY OF A CONDITION THAT COULD HAVE PREVENTED FULFILLMENT OF A SAFETY FUNCTION

"On May 7, 2018, during an engineering review of mission time requirements for Technical Specification related equipment, a deficiency was discovered regarding the Emergency Operating Procedure (EOP) guidance for natural circulation cooldown with a stagnant loop. This condition could be the result of a postulated Main Steam Line Break with a loss of offsite power.

"During a natural circulation cooldown with a faulted steam generator, flow in the stagnant reactor coolant system (RCS) loop associated with the isolated faulted steam generator (SG) could stagnate and result in elevated temperatures in that loop. This becomes an issue when RCS depressurization to residual heat removal system (RHR) entry conditions is attempted. The liquid in the stagnant loop will flash to steam and prevent RCS depressurization. In this condition, the time required to complete the cooldown would be sufficiently long that the nitrogen accumulators associated with Callaway's atmospheric steam dumps and turbine driven auxiliary feedwater pump flow control valves would be exhausted. The atmospheric steam dumps and turbine driven auxiliary feedwater pump would not be capable of performing their specified safety functions of cooling the plant to entry conditions for RHR operation. This issue has been analyzed by Westinghouse in WCAP-16632-P. This WCAP determined that to prevent loop stagnation, the RCS cooldown rate in these conditions should be limited to a rate dependent on the temperature differential present in the active loops.

"The WCAP analysis was used to support a revision to the generic Emergency Response Guideline (ERG) for ES-0.2 "Natural Circulation Cooldown." Figure 1 in ES-0.2 provides a curve of the maximum allowable cooldown rate as a function of active loop temperature differential which is directly proportional to the level of core decay heat. At the time of discovery of this condition, Callaway's EOP structure did not ensure that the ES-0.2 guidance would be implemented for a natural circulation cooldown with a stagnant loop.

"Callaway has issued interim guidance to the on-shift personnel regarding this concern and is in the process of revising the applicable EOPs.

"This condition is reportable per 10 CFR 50.72(b)(3)(v) for 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 (A) Shutdown the reactor and maintain it in a safe shutdown condition, (B) Remove residual heat, or (D) mitigate the consequences of an accident."

The licensee notified the NRC Resident Inspector of this condition.

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