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Event Notification Report for March 07, 2017

U.S. Nuclear Regulatory Commission
Operations Center

EVENT REPORTS FOR
03/06/2017 - 03/07/2017

EVENT NUMBERS
52597

Power Reactor
Event Number: 52597
Facility: SEQUOYAH
Region: 2     State: TN
Unit: [1] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: JONATHAN REDNER
HQ OPS Officer: JEFF ROTTON
Notification Date: 03/07/2017
Notification Time: 14:39 [ET]
Event Date: 03/07/2017
Event Time: 08:30 [EST]
Last Update Date: 03/07/2017
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(C) - POT UNCNTRL RAD REL 50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Person (Organization):
BINOY DESAI (R2DO)
Power Reactor Unit Info
Unit SCRAM Code RX Crit Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N Y 100 Power Operation 100 Power Operation
2 N Y 100 Power Operation 100 Power Operation
Event Text
BREACH IN AUXILIARY BUILDING SECONDARY CONTAINMENT

"At 0830 [EST] on March 7, 2017, operators discovered that on March 3, 2017 at 2046 a door was blocked open creating a breach of the auxiliary building secondary containment enclosure (ABSCE) boundary that exceeded the allowed ABSCE breach margin. As a result, both Unit 1 and Unit 2 entered Technical Specification Limiting Condition of Operation (LCO) 3.7.12 Condition B for two trains of Auxiliary Building Gas Treatment System (ABGTS) inoperable due to an inoperable ABSCE boundary in MODE 1, 2, 3, or 4. The condition has been corrected and ABGTS was restored to operable as of 0949 March 7, 2017.

"In MODES 1, 2, 3, and 4, the analysis of the loss of coolant accident (LOCA) assumes that radioactive materials leaked from the Emergency Core Cooling System are filtered and adsorbed by the ABGTS. For the fuel handling accident, the analysis assumes that the ABSCE boundary is capable of being established to ensure releases from the auxiliary and containment buildings are consistent with the dose consequence analysis.

"The event is reportable in accordance with 10 CFR 50.72(b)(3)(v) as an event or condition that could have prevented fulfillment of a safety function of structures or systems that are needed to: (C) control the release of radioactive material and (D) mitigate the consequences of an accident.

"No actual LOCA or fuel handling accident occurred while both trains of ABGTS were inoperable. The condition had no impact on the health and safety of the public.

"The NRC Resident Inspector has been notified."