CNL-15-131, Individual Plant Examination of External Events (IPEEE) Report, Revision 3

Individual Plant Examination of External Events (IPEEE) Report, Revision 3

ML15196A544
Person / Time
Site:	Watts Bar
Issue date:	07/15/2015
From:	James Shea Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNL-15-131
Download: ML15196A544 (7)

Text

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-15-131 July 15, 2015 10 CFR 50.54(f)

ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-001 Watts Bar Nuclear Plant, Unit 2 Construction Permit No. CPPR-92 NRC Docket No. 50-391

Subject:

WATTS BAR NUCLEAR PLANT UNIT 2 - INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE) REPORT, REVISION 3

Reference:

Letter from TVA to NRC, Watts Bar Nuclear Plant Unit 2 - Individual Plant Examination of External Events Final Report, dated March 20, 2015 The purpose of this letter is to provide Revision 3 of the Watts Bar Nuclear Plant (WBN)

Unit 2, Individual Plant Examination of External Events (IPEEE) Report. Revision 2 of the IPEEE Report was previously submitted in the referenced letter. Revision 3 impacts three pages (i.e., page 1 - cover page, page 29 - Table 2-3, and page 48 - references).

The Tennessee Valley Authority (TVA) recently revised calculation CDQ0009992012000125, Updated WBN Seismic IPEEE HCLPF Capacity, to establish a High Confidence Low Probability of Failure (HCLPF) capacity of at least 0.50g, consistent with IPEEE implementation requirements for a 0.50g Review Level Earthquake plant. The calculation revision specifically involved a reassessment of the seismic margin for the Refueling Water Storage Tank. The revised page 29 included in Enclosure 1 reflects the new HCLPF value for the Refueling Water Storage Tank.

In the process of revising the report to reflect the new Refueling Water Storage Tank value, TVA identified several other values on page 29 of the report that needed to be updated to reflect previous changes to HCLPF capacities for other plant components. Due to an oversight, the other values were not updated when Revision 2 of the report was submitted on March 20, 2015. The WBN Unit 2 HCLPF seismic capacity remains above 0.50g.

U.S. Nuclear Regulatory Commission CNL-15-131 Page 2 July 15, 2015 provides the revised pages. Enclosure 2 provides the filing instructions to update the Revision 2 document previously provided in the above reference.

There are no new regulatory commitments made in this letter. Should you have questions regarding this submittal , please contact Gordon Arent at (423) 365-2004.

Enclosures:

1. Watts Bar Nuclear Plant, Unit 2 - Individual Plant Examination of External Events, Final Report, Revision 3

2. Filing Instructions cc (Enclosures) :

U.S. Nuclear Regulatory Commission , Region II NRC Project Manager - Watts Bar Nuclear Plant, Unit 2 NRC Senior Resident Inspector - Watts Bar Nuclear Plant, Unit 2

Enclosure 1 Watts Bar Nuclear Plant, Unit 2 - Individual Plant Examination of External Events, Final Report, Revision 3

T96150429001 T96150429001 Revision 3 April 16, 2015 Table 2-3: WBN2 Updated HCLPF Seismic Capacities (Reference [19])

HCLPF Description Key Considerations Capacity 6900V Shutdown Boards 0.57g Seismic demand based on ACB median centered response spectra 480V Shutdown Board 0.85g Seismic demand based on ACB median centered response Transformers (Modified) spectra Governed by base attachment bolts which are readily accessible.

These were changed out to higher strength bolts eliminated anchorage as a weak link and significantly increased HCLPF capacity, now governed by the tested functional capacity.

CCS Heat Exchangers 0.58g Seismic demand based on ACB median centered response spectra Actual piping nozzle loads used ERCW Pumps 1.27g WBN IPS Screen Wash Pump configuration specifically evaluated (not scaled from SQN)

Actual piping nozzle loads were used.

IPS Screen Wash Pumps 0.80g WBN IPS Screen Wash Pump configuration specifically evaluated (not scaled from SQN)

Actual piping nozzle loads used.

480V RMOV Boards 0.69g Seismic demand based on ACB median centered response spectra 480V Reactor Vent Boards 0.75g Seismic demand based on ACB median centered response spectra 480V Control & Aux. Boards 0.89g Seismic demand based on ACB median centered response spectra RWST 0.61g WBN RWST configuration specifically evaluated including thicker tank shell, larger anchor bolts, and shear keys Block Walls 0.53g No change from WBN1 evaluation (Reference [4]).

Main Control Room Ceiling 0.52g Based on non-liner analysis results and scaled B+C ARS for the ACB.

WBN2 IPEEE FINAL REPORT Page 29

T96150429001 Revision 3 April 16, 2015

14. Watts Bar Design Criteria Document No. WB-DC-20-32, Integrated Interaction Program Screening and Acceptance Criteria, Revision 05.

15. Tennessee Valley Authority Design Criteria No. WB-DC-40-31.2, Seismic/Structural Qualification of Seismic Category I Electrical and Mechanical Equipment, Revision 11, April 2009.

16. United States Nuclear Regulatory Commission, Generic Letter No. 88-20, Supplement 5 dated September 8, 1995, Individual Plant Examination of External Events (IPEEE) for Severe Accident Vulnerabilities.

17. Tennessee Valley Authority Letter to NRC dated December 5, 2000, "Sequoyah Nuclear Plant (SQN) - Units 1 and 2 - Response to Request for Additional Information on the Individual Plant Examination of External Events (IPEEE) (TAC nos. M83674 and M83675)," RIMS No. S64 001205 802.

18. United States Nuclear Regulatory Commission Letter to TVA dated February 21, 2001, "Sequoyah Nuclear Plant, Units 1 and 2 - Review of Sequoyah Individual Plant Examination of External Events Submittal (TAC Nos. M83674 and M83675)."

19. Tennessee Valley Authority Calculation No. CDQ 000 999 2012 000125, Updated WBN Seismic IPEEE HCLPF Capacity, Rev 02.

20. United States Nuclear Regulatory Commission Letter to TVA dated February 3, 2012, Watts Bar Nuclear Plant Unit 2 Construction - NRC Integrated Inspection Report 05000391/2011610.

21. Seismic Qualification Utility Group (SQUG), Generic Implementation Procedure (GIP) for Seismic Verification of Nuclear Plant Equipment, Revision 3A, December 2001.

22. Tennessee Valley Authority Calculation No. CDQ 000 999 2014 000619, WBN2 Seismic IPEEE Walkdown Screening Evaluations, Rev 0.

23. Tennessee Valley Authority Design Criteria No. WB-DC-40-31.12, Seismic/Structural Qualification of Seismic Category I and I(L) In-Line Valves and Other In-Line Fluid System Components, Rev. 11.

24. Tennessee Valley Authority, Updated Final Safety Analysis Report, Amendment 7, Submitted to the NRC September 2008.

25. Tennessee Valley Authority Calculation No. WCG-2-617, Seismic Margin Assessment of Main Control Room Ceiling, Revision 0, March 2010.

26. U.S. Nuclear Regulatory Commission (NRC), NUREG/CR-0098, "Development of Criteria for Seismic Review of Selected Nuclear Power Plants," N.M. Newmark and W. J. Hall, May 1978.

27. United States Nuclear Regulatory Commission, Regulatory Guide 1.59, Design Basis Floods for Nuclear Power Plants, Revision 2, August 1977.

WBN2 IPEEE FINAL REPORT Page 48

Enclosure 2 Filing Instructions Update Individual Plant Examination of External Events (IPEEE) Report, Revision 2 to Revision 3 by performing the following:

Revision 2 to Revision 3 Remove Cover Page 1 Replace with Cover Page 1 Remove Page 29 - Table 2-3 Replace with Page 29 - Table 2-3 Remove Page 48 - References Replace with Page 48 - References