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Request for Approval of an Alternative (IST-RR-5) to the Testing Requirements of American Society of Mechanical Engineers (ASME) Operation and Maintenance (OM) Code for Class 1 Safety Valves
	ML16054A586
Person / Time
Site:	Watts Bar
Issue date:	02/23/2016
From:	James Shea; Tennessee Valley Authority
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	CNL-16-028
	Download: ML16054A586 (6)
	v • d • e

Tennessee Valley Authority,1101 Market Street, Chattanooga , Tennessee 37402 CNL-16-028 February 23, 2016 10 CFR 50.55a ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 2 Facility Operating License No. NPF-96 NRC Docket No. 50-391

Subject:

Watts Bar Nuclear Plant Unit 2 - Request for Approval of an Alternative (IST-RR-5) to the Testing Requirements of American Society of Mechanical Engineers (ASME) Operation and Maintenance (OM) Code for Class 1 Safety Valves

Reference:

NRC Letter to TVA, "Watts Bar Nuclear Plant, Unit 2 Review of lnservice test Program and Preservice Test Program, and Safety Evaluation of Relief Requests IST-RR-1/2/3/4 for the First 10-Year Interval of the lnservice Testing program (TAC NO. MF4118)," dated October 21 , 2014 (ML14289A222)

In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a, "Codes and Standards," paragraph (z)(1), Tennessee Valley Authority (TVA) is requesting the Nuclear Regulatory Commission (NRC) approval of the enclosed request for an alternative (IST-RR-5) to the requirements of the American Society of Mechanical Engineers (ASME)

Operation and Maintenance (OM) Code, 2004 Edition through 2006 Addenda , Mandatory Appendix I, Section 1-7210, Class 1 Safety Valves, for the Watts Bar Nuclear Plant (WBN)

Unit 2 Class 1 pressurizer safety valves.

ASME OM Code, Mandatory Appendix I, Section 1-7210, "Class 1 Safety Valves ," states "Within 6 months before initial reactor criticality, each valve shall have its set-pressure verified ." For WBN Unit 2, initial criticality is considered to be achieved when the plant is in Mode 2 as defined in the WBN Unit 2 Technical Specifications.

The WBN Unit 2 Class 1 pressurizer safety valves (PSVs) 2-RFV-68-563, 2-RFV-68-564, and 2-RFV-68-565 were satisfactorily tested in accordance with ASME OM Code, Mandatory Appendix I, Section 1-7210 on October 14, 2015, October 15, 2015, and

U.S. Nuclear Regulatory Commission CNL-16-028 Page 2 February 23, 2016 October 13, 2015, respectively. This testing was performed in accordance with TVA relief request IST-RR-4, which was approved by the NRC in the referenced letter. IST-RR-04 requested relief from the ASME OM Code, Mandatory Appendix I, Section 1-721 O requirement to verify set pressure while the valves are installed in the plant using system pressure or reduced system pressure with an assist device.

In order to comply with the six month requirement of ASME OM Code, Mandatory Appendix I, Section 1-7210, WBN Unit 2 would need to achieve initial criticality (i.e. , Mode 2) no later than April 13, 2016 (i.e., six months from the earliest test date of October 13, 2015).

The scheduled WBN Unit 2, Mode 2 date is March 29, 2016. However, TVA is requesting additional margin in the event that WBN Unit 2 is not able to achieve Mode 2 before April 13, 2016.

Therefore, pursuant to 10 CFR 50.55a(z)(1), TVA is requesting an alternative to the ASME OM Code, Mandatory Appendix I, Section 1-7210 requirement for testing the PSVs within six months of initial criticality. Specifically, TVA is requesting the six months prior to initial criticality requirement be extended to nine months prior to initial criticality. This alternative request would extend the time period for compliance with ASME OM Code, Mandatory Appendix I, Section 1-7210 from April 13, 2016 to July 13, 2016. provides a description and assessment of the proposed request for alternative, and the basis as to why the proposed alternative provides an acceptable level of quality and safety in accordance with 10 CFR 50.55a(z)(1). TVA requests NRC approval of this alternative request by April 8, 2016.

Enclosure 2 provides the new regulatory commitment associated with this submittal. Please address any questions regarding this response to Mr. Gordon Arent at 423-365-2004.

ce President, Nuclear Licensing

Enclosures:

1. Request for Alternative Number IST-RR-5, Pressurizer Safety Valve Testing Before Initial Electric Power Generation

2. List of Commitments cc (Enclosures):

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Watts Bar Nuclear Plant, Unit 1 NRC Senior Resident Inspector - Watts Bar Nuclear Plant, Unit 2 NRR Project Manager - Watts Bar Nuclear Plant

ENCLOSURE 1 TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT UNIT 2 DOCKET NO. 50-391 IST-RR-5 Pressurizer Safety Valve Testing Before Initial Electric Power Generation Proposed Alternative in Accordance with 10 CFR 50.55a(z)(1)

Acceptable Level of Quality and Safety ASME Code Component(s) Affected Valve ID Function Drawing /Coord Cat AcUPass Class Size 1 Type Act 2-RFV-68-563 PR ESSURIZER SAFETYVALVE 2-47W81 3-1 / A-2 c Active 1 6 RVL SA 2-RFV-68-564 PRESSURIZER SAFETYVALVE 2-47W813-1 /A-2 c Active 1 6 RVL SA 2-RFV-68-565 PRESSURIZER SAFETYVALVE 2-47W813-1 /A-2 c Active 1 6 RVL SA

Applicable Code Edition and Addenda

ASME OM Code, 2004 Edition through 2006 Addenda

Applicable Code Requirement

Mandatory Appendix I, Section I-7210 Class 1 Safety Valves "Within 6 months before initial reactor criticality, each valve shall have its set-pressure verified ."

Reason for Request

Relief is being requested from the requirement to verify set-pressures for the Watts Bar Nuclear Plant (WBN) Unit 2 pressurizer safety valves (PSVs) within six months before initial reactor criticality. The basis of the request is that the proposed alternative would provide an acceptable level of quality and safety. Specifically, Tennessee Valley Authority (TVA) is requesting that the ASME OM Code, Mandatory Appendix I, Section 1-7210 requirement to test the PSVs within six months of initial criticality be extended to nine months before initial criticality.

This alternative request would extend the time period for compliance with Section 1-7210 from April 13, 2016 (i.e., six months from the date that the PSVs were last tested) to July 13, 2016.

TVA requests the contingency of extending the due date for compliance with Section 1-7210 in order to have additional margin to reduce the potential effect on other plant activities and reduce the risk of having to regress the plant operating mode in order to perform the required testing should the initial criticality date exceed April 13, 2016.

1 In TVA relief request IST-RR-4 (Reference 1) this valve size was incorrectly reported as 1. This error has been entered into the TVA corrective action program .

CNL-16-028 E1 -1 of 3

Proposed Alternative and Basis for Use TVA proposes a contingency to extend the time interval for verifying set-pressure testing of the WBN Unit 2 PSVs prior to initial reactor criticality from six months to nine months. If it becomes necessary to utilize th is extension , TVA will remove and test (or replace with pretested valves) the WBN Unit 2 PSVs at the first refueling outage. If WBN Unit 2 is able to achieve initial criticality by April 13, 2016, then this relief request will not be implemented and testing at the first refueling outage will be in accordance with the ASME OM Code requ irements .

The WBN Unit 2 PSVs Serial Numbers N56964-10-0118 , -0119 , and -0 120 (which correspond to 2-RFV-68-563 , 2-RFV-68-564 , and 2-RFV-68-565 ) have a design set pressure of 2485 psig and were as-left tested at the vendor's facility on April 29, 2011 , April 28, 2011 , and May 3, 2011 , respectively. The as-left set pressures were 2485 psig , 2501 psig, and 2481 psig ,

respectively. After installing the PSVs and performing hot functional testing , TVA removed the valves and sent them to an off-site test facility where they were retested on October 14, 2015, October 15, 2015, and October 13, 2015, respectively. The initial (as-found) set pressures were 2446 psig (1. 57% off set pressure, low), 2505 psig (0.8% off set pressure, high) , and 2546 psig (2.45% off set pressure, high), respectively. The as-found set pressures were within the ASME OM Code, Mandatory Appendix I, Section 1-1320 allowed three percent tolerance fo r as-found set pressure.

By comparing the difference between the as-left tests at the vendor in 20 11 to the as-found tests in 2015, the amount of set pressure drift from 2011 to 2015 was determined . For these PSVs, the drift in set pressure between 2011 .and 2015 (approximately 4 years and 5-1 /2 months) was 1.57% (low), 0.16% (high), and 2.62% (high), respectively. Although not an OM Code criteria , the set pressure drifts between 2011 and 2015 were also with in three percent of design set pressure.

The test data from 2011 and 2015 provide high confidence that the set pressures for these valves will remain within the allowable OM Code tole rances until the first WBN Unit 2 refuel ing outage (currently scheduled for October 9, 2017) .

Summary of PSV Set Pressure Test Information As-Left As-Found Code Drift Valve S/N Design Set Pressure Set Pressure (Design vs. (As-Left vs N56964 Set Pressure As-Found) As-Found)

Date Date 2485 psig 2446 psig 011 8 2485 psig 1.57% (low) 1.57% (low)

April 29, 201 1 Oct 14, 20 15 2501 psig 2505 psig 0119 2485 psig 0.8% (high) 0.16% (high)

April 28, 201 1 Oct15, 2015 2481 psig 2546 psig 0120 2485 psig 2.45% (high) 2.62% (high)

May 3, 2011 Oct 13, 2015 CNL-16-028 E1-2 of 3

The WBN Unit 2 PSVs are a proven design considering that they are interchangeable with the PSVs at WBN Unit 1 and Sequoyah Nuclear Plant, Units 1 and 2. Additionally, the pressurizer relief system configurations are similar amongst these units.

To verify set pressures would require TVA to either replace the PSVs with pretested valves, or remove and test the PSVs at an off-site facility. Either option would require intensive work in a short time, affect other work and test activities currently underway, and could delay startup of WBN Unit 2 by causing a regression in plant status to a lower operating mode.

OM Code, Mandatory Appendix I, Section l-1 320(a) requires 20 percent of these valves to be tested within any 24 month period and all to be tested within five years. Potentially extending the time period for testing before initial criticality from six months to nine months will not affect that requirement. If the extension is applied and the first refueling outage is scheduled for October 9, 2017, the PSVs will be tested within 24 months, which would exceed the OM Code requirement to test 20% of the valves within any 24 month period and would also meet the OM Code requirement to test all of the valves within five years. Testing the PSVs at the first refueling outage (if required) would provide additional assurance that the PSVs will remain within the OM Code allowed three percent tolerance for as-found set pressure. Therefore, the OM Code requirements for percentages and frequency will be met.

Based on the information provided above, the proposed alternative provides an acceptable level of quality and safety and provides reasonable assurance of the operational readiness of the WBN Unit 2 PSVs.

Duration of Proposed Alternative This request is for the duration of the WBN Unit 2 Preservice Test period .

Precedents A similar relief request was approved by the NRC for WBN Unit 1 (Reference 2).

References

1. TVA Letter to NRC, "Watts Bar Nuclear Plant (WBN) Unit 2 - lnservice Test (IST)

Program/Preservice Test (PST) Program," dated May 8, 2014(ML14133A296)

2. NRC Letter to TVA, "Watts Bar Unit 1 - Relief from ASME Section XI Regarding Pressurizer Safety Valve Testing (TAC NO. M92773)," dated September 5, 1995 (ML073200567)

CNL-16-028 E1-3 of 3

ENCLOSURE 2 LIST OF COMMITMENTS

1. If the contingency to extend the time interval (from six months to nine months) is applied ,

TVA will remove and test (or replace with pretested valves) the WBN Unit 2 pressurizer safety valves at the first refueling outage.

CNL-16-028 E2-1 of 1