05000259/FIN-2009008-01

Finding

Title

Violation of Technical Specification 5.4.1 for Failure to Develop Adequate Procedures to Ensure Tornado Depressurization Protection of the Emergency Diesel Generators

Description

The inspectors identified a Green non-cited violation (NCV) of TS 5.4.1 for the failure to have an adequate procedure that would ensure tornado depressurization protection of the emergency diesel generators (EDGs). Abnormal Operating Instruction, 0-AOI-100-7, Severe Weather, did not provide guidance on how to provide pressure equalization of the EDG building for mitigating atmospheric depressurization associated with tornado conditions that could impact the EDG building ventilation system. The design of the EDG ventilation system intake and exhaust dampers requires the dampers to be manually opened prior to a tornado depressurization event to ensure the EDG building and ventilation system remain intact and operable during and after a tornado. This finding was entered into the licensees corrective action program as problem evaluation report (PER) 206919. As an immediate corrective action, the licensee added steps to procedure 0-AOI-100-7 to station an operator in the EDG building to perform required manual actions in the event of a tornado warning in the area. This finding is more than minor because it affects the Mitigating Systems Cornerstone objective of ensuring the availability, reliability, and operability of the EDGs to perform the intended safety function during a design basis event and the cornerstone attribute of Procedure Quality, i.e. Operating (Post Event) Procedures (AOPs). The inspectors assessed the finding using a Phase I Significance Determination Process (SDP) screening which determined a Phase III SDP evaluation was required due to the fact that the finding involved the loss or degradation of equipment specifically designed to mitigate a severe weather initiating event (e.g., tornado doors). The loss of this equipment by itself, during the external initiating event it was intended to mitigate, would degrade two or more trains of a multi-train safety system. A Phase III SDP evaluation was performed in accordance with NRC Inspection Manual Chapter 0609 Appendix A by a regional Senior Reactor Analyst using the NRC Standardized Plant Analysis Risk (SPAR) model. The analysis determined that the performance deficiency resulted in a core damage frequency (CDF) risk increase of less than 1E-6. Therefore, the finding was characterized as having very low safety significance (Green). The large early release frequency (LERF) result was less than 1E-7 which would not override the CDF risk characterization. The dominant sequence was a tornado which caused damage to the EDG dampers for all EDGs and resulted in a loss of offsite power (LOOP). The risk was mitigated by the low initiating event likelihood for tornadoes and the probability for EDG recovery which was proceduralized. The inspectors determined that the use of operating experience (OE) information was a significant cause of this performance deficiency. Regulatory Information Summary 2006-03, Post Tornado Operability of Ventilation and Air Conditioning Systems as well as an internal licensee OE had raised a similar concern. The licensee was unaware of the vulnerability of the EDG ventilation system to tornado depressurization events until it was brought to their attention by the inspectors. The licensees failure to use available OE is directly related to the OE component of the cross-cutting area of Problem Identification and Resolution and the aspect of implementing OE through changes to procedures (P.2.(b))

01
Site:	Browns Ferry
Report	IR 05000259/2009008 Section 1R21
Date counted	Dec 31, 2009 (2009Q4)
Type:	NCV: Green
cornerstone	Mitigating Systems
Identified by:	NRC identified
Inspection Procedure:	IP 71111.21
Inspectors (proximate)	J Leivo R Aiello R Berryman H Campbell C Even R Patterson B Desai J Kent
CCA	P.5, Operating Experience
INPO aspect	CL.1
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Finding - Browns Ferry - IR 05000259/2009008

2(6)3(6)4(4)5(4)6(2)7(4)8(4)9(4)301(0)402(0)403(0)501(0)23(0)

IR 05000259/2009008: 1 2 3 4

Finding List (Browns Ferry) @ 2009Q4

CCA Matrix: 2009Q4

	Q	CCA	Title
05000259/FIN-2009002-02	2009Q1	P.2	Inadequate Surveillance Procedure Causes Loss of Unit 1 RHR System Safety Function (Section 1R22)
05000259/FIN-2009002-03	2009Q1		Unit 1 RPV Flange Leak Due to Lack of Prompt Identification and Resolution (Section 4OA2.3)
05000259/FIN-2009002-04	2009Q1	H.14	Main Generator Voltage Regulator Relay Failure Results in Unit 2 Reactor Scram (Section 4OA3)
05000259/FIN-2009002-01	2009Q2		Inappropriate Change to SSI Entry Conditions For Appendix R Fire Events (Section 1R15)
05000259/FIN-2009003-03	2009Q2	H.11 H.12	Failure to Comply with the Requirements of an RWP by Entering a Posted High Radiation Area
05000259/FIN-2009003-01	2009Q2	H.4 H.5	Failure to Assess and Manage Shutdown Risk Associated with Outage maintenance Activities
05000259/FIN-2009007-04	2009Q2		Categorization of Operator Manual Actions as Meeting Appendix R Section III.G.1 versus III.G.2
05000259/FIN-2009007-03	2009Q2		Operator Manual Actions to Isolate Main Steam Safety Relief Valves for a Unit 2 Appendix R Fire Event
05000259/FIN-2009007-02	2009Q2		Containment Isolation Valves not Included in the Appendix R Separation Analysis
05000259/FIN-2009007-01	2009Q2		Suppression Pool Initial Temperature Assumed in the Appendix R Thermo-Hydraulic Analysis May not be the Most Limiting Value
05000259/FIN-2009003-05	2009Q2	P.3	Untimely Actions to Resolve Excessive IBC System Condensation Results in Unit 1 Reactor Scram
05000259/FIN-2009003-02	2009Q2	H.7	Failure to Perform an Adequate Risk Assessment During Severe Weather Conditions
05000259/FIN-2009003-04	2009Q2		Inadequate Scoping of Risk Significant Systems For Online Risk Assessment
05000259/FIN-2009004-01	2009Q3		Unit 3 Reactor Core Isolation Cooling Pump Flow Oscillations
05000259/FIN-2009006-01	2009Q3	P.2	Standby Gas Treatment Subsystem A Inoperable Beyond the Technical Specification Allowed Outage Time
05000259/FIN-2009009-02	2009Q4	H.5	Failure to Establish Adequate Compensatory Measures for an Out-of-Service Hose Station
05000259/FIN-2009005-03	2009Q4	H.7	Inadequate Operating Procedures Cause Partial Loss of Reactor Feedwater Which Results In Unit 2 Manual Reactor Scram
05000259/FIN-2009005-04	2009Q4	P.1 P.1(a)	Unit 2 RCIC System Inoperable Beyond the Technical Specification Allowed Outage Time
05000259/FIN-2009008-01	2009Q4	P.5	Violation of Technical Specification 5.4.1 for Failure to Develop Adequate Procedures to Ensure Tornado Depressurization Protection of the Emergency Diesel Generators
05000259/FIN-2009008-02	2009Q4		Violation of 10CFR50, Appendix B, Criterion V for Inadequate Procedure for Emergency Equipment Cooling Water System Flow Balancing
05000259/FIN-2009009-03	2009Q4	P.3	Failure to Protect Cables of Systems Necessary to Achieve and/or Maintain Post-Fire Safe Shutdown Conditions for Fire Areas Subject to the Requirements of 10 CFR Part 50, Appendix R, Section III.G.2
05000259/FIN-2009009-01	2009Q4	H.5	Deficiencies with Emergency Lighting Units
05000259/FIN-2009008-03	2009Q4		Safety-Related Molded Case Circuit Breakers
05000259/FIN-2009009-04	2009Q4	P.2	Failure to Meet the Requirements of 10 CFR Part 50, Appendix R, Section III.G.1 for 20 Fire Areas
05000259/FIN-2009005-02	2009Q4	P.3	Failure to Report a Safety System Functional Failure Per 10 CFR 50.73
05000259/FIN-2009005-01	2009Q4	P.2	Failure to Report an Automatic RPS Actuation While Shutdown Per 10 CFR 50.73

Self-Identified List (Browns Ferry)

	Q	Title
05000259/FIN-2009002-05	2009Q1	Licensee-Identified Violation
05000259/FIN-2009002-06	2009Q1	Licensee-Identified Violation
05000259/FIN-2009003-06	2009Q2	Licensee-Identified Violation
05000259/FIN-2009004-02	2009Q3	Licensee-Identified Violation
05000259/FIN-2009004-03	2009Q3	Licensee-Identified Violation
05000259/FIN-2009004-04	2009Q3	Licensee-Identified Violation
05000259/FIN-2009006-02	2009Q3	Licensee-Identified Violation
05000259/FIN-2009008-04	2009Q4	Licensee-Identified Violation

[Browns Ferry Findings full list]

05000259/FIN-2009008-01

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