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Event Notification Report for April 21, 2016

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
04/20/2016 - 04/21/2016

** EVENT NUMBERS **


51872 51874

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Power Reactor Event Number: 51872
Facility: SUSQUEHANNA
Region: 1 State: PA
Unit: [1] [2] [ ]
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: RON FRY
HQ OPS Officer: VINCE KLCO
Notification Date: 04/20/2016
Notification Time: 01:52 [ET]
Event Date: 04/19/2016
Event Time: 21:59 [EDT]
Last Update Date: 04/20/2016
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(C) - POT UNCNTRL RAD REL
Person (Organization):
CHRISTOPHER CAHILL (R1DO)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N N 0 Cold Shutdown 0 Cold Shutdown
2 N Y 100 Power Operation 100 Power Operation

Event Text

INOPERABLE SECONDARY CONTAINMENT

"On April 19th, 2016 at 2159 [EDT], Secondary Containment became inoperable due to failure to meet Surveillance Requirement (SR 3.6.4.1.1) on Unit 1 and Unit 2.

"The inoperability was caused when Reactor Building differential pressure was discovered to be less than Technical Specification requirements [-0.25 inches of water gauge].

"Secondary Containment was restored April 19, 2016 at 2222 by adjusting intake louvers in accordance with off normal operating procedure ON-RBHVAC-201.

"This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system."

The licensee notified the NRC Resident Inspector.

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Power Reactor Event Number: 51874
Facility: CALLAWAY
Region: 4 State: MO
Unit: [1] [ ] [ ]
RX Type: [1] W-4-LP
NRC Notified By: DAVID HURT
HQ OPS Officer: JEFF HERRERA
Notification Date: 04/20/2016
Notification Time: 22:04 [ET]
Event Date: 04/20/2016
Event Time: 14:05 [CDT]
Last Update Date: 04/20/2016
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
Person (Organization):
HEATHER GEPFORD (R4DO)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N N 0 Defueled 0 Defueled

Event Text

UNANALYZED CONDITION DUE TO ESSENTIAL SERVICE WATER PRESSURE TRANSIENT

"Recent Operating Experience at Callaway has shown that the pressure transient experienced in the Essential Service Water (ESW) system during Engineered Safety Feature Actuation System (ESFAS) testing can result in gasket failure on the Control Room Air Conditioners rendering the units nonfunctional. Previously, this pressure transient was considered to be the result of the system alignment used to perform the surveillance test, which is not the same as the system lineup which would occur on an actual Loss of Offsite Power (LOOP) or Safety Injection Signal Design Basis Accident (DBA) event. However, on April 20th, 2016, Callaway received preliminary analysis results that predict the Control Room Air Conditioners would actually experience a greater pressure transient during a DBA than what is currently experienced during ESFAS testing. This condition could result in the Control Room Air Conditioners not being capable of performing their safety function following a DBA event, and challenge Control Room Habitability. Therefore, this condition meets the reporting criteria of 10 CFR 50.72(b)(3)(ii)(B).

"Based on current conditions (i.e., the plant is not in Power Operation), this condition does not present an immediate safety concern.

"The analysis of the pressure transient experienced by the ESW system during a postulated DBA event is preliminary and further evaluation of the analysis is ongoing.

"The NRC Resident Inspector has been notified."

Page Last Reviewed/Updated Thursday, April 21, 2016
Thursday, April 21, 2016