BVY 12-086, Inservice Inspection Program Relief Request ISI-PT-02, (Fourth ISI Program Interval)

Inservice Inspection Program Relief Request ISI-PT-02, (Fourth ISI Program Interval)

ML12362A013
Person / Time
Site:	Vermont Yankee
Issue date:	12/21/2012
From:	Wamser C Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BVY 12-086
Download: ML12362A013 (9)

Text

Entergy Nuclear Operations, Inc.

Vermont Yankee 320 Governor Hunt Rd

%-lmýEnhqW Vernon, VT 05354 Tel 802 257 7711 Christopher J. Wamser Site Vice President BVY 12-086 December 21, 2012 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555

SUBJECT:

Inservice Inspection Program Relief Request ISI-PT-02 (Fourth ISI Program Interval)

Vermont Yankee Nuclear Power Station Docket No. 50-271 License No. DPR-28

Dear Sir or Madam:

Pursuant to 10 CFR 50.55a(a)(3)(ii), Entergy Nuclear Operations, Inc. (Entergy) hereby requests NRC approval of the following relief request for Vermont Yankee Nuclear Power Station (VY) for the fourth ten-year inservice inspection (ISI) program interval, which began on September 1, 2003.

Entergy has determined that compliance with certain inspection requirements of ASME Section XI would result in unnecessary hardship or unusual difficulty without a compensating increase in the level of quality and safety. The details of the proposed relief request are attached.

Entergy requests approval by March 1, 2013, to support the upcoming VY refueling outage in March 2013.

There are no new regulatory commitments being made in this submittal.

If you have any questions or require additional information, please contact Mr. Robert J. Wanczyk at (802) 451-3166.

Sincerely, CJW/plc cc list: next page bqj

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BVY 12-086 / Page 2 of 2 Attachments: 1. 10 CFR 50.55a Relief Request ISI-PT-02

2. Reactor Pressure Vessel Head Flange Leak-Off Lines Sketches cc: Mr. William M. Dean Regional Administrator, Region 1 U.S. Nuclear Regulatory Commission 2100 Renaissance Blvd, Suite 100 King of 'Prussia, PA 19406-2713 Mr. Richard V. Guzman, Project Manager Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 08C2A Washington, DC 20555 USNRC Resident Inspector Entergy Nuclear Vermont Yankee, LLC 320 Governor Hunt Rd Vernon, VT 05354 Ms. Elizabeth Miller, Commissioner VT Department of Public Service 112 State Street - Drawer 20 Montpelier, VT 05620-2601

BVY 12-086 Docket No. 50-271 Attachment 1 Vermont Yankee Nuclear Power Station 10 CFR 50.55a Relief Request ISI-PT-02

BVY 12-086 / Attachment 1 / Page 1 of 3 10 CFR 50.55a Relief Request ISI-PT-02 Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(ii)

--Hardship or Unusual Difficulty without a Compensating Increase in Level of Quality or Safety--

1. ASME Code Components Affected

Description:

Reactor pressure vessel head flange leak-off lines originating from reactor vessel nozzles N-13 and N-14 ASME Code Class: 2 Examination Category: C-H (all pressure retaining components)

Item Number: C7.10 Components Affected: Valve FCV-2-20, valve FCV-2-21, orifice RO-2-23, valve V2-22, excess flow check valve SL-2-23, pressure instrument PI-2-101, pressure switch PS-2-102, and associated piping and fittings

2. Applicable Code Edition and Addenda ASME Boiler and Pressure Vessel Code,Section XI, 2001 Edition through 2003 Addenda

3. Applicable Code Requirement IWC-5221: The system leakage test shall be conducted at the system pressure obtained while the system, or portion of the system, is in service performing its normal operating function or at the system pressure developed during a test conducted to verify system operability (e.g., to demonstrate system safety function or satisfy technical specification surveillance requirements).

4. Reason for Request The ASME Boiler and Pressure Vessel Code requirement for the ASME Code Class 2 reactor pressure vessel (RPV) head flange leak-off lines is to perform a system leakage test at a pressure corresponding to 100% rated power. This is approximately 1005 psig.

However, the configuration of the leak-off lines makes testing difficult and presents a personnel and equipment hazard.

The RPV head flange leak-off line originating from reactor vessel nozzle N13 (N13 leak-off line) is separated from the reactor coolant pressure boundary by one passive membrane, which is a metallic seal ring located on the inner vessel flange. A second seal ring is located on the outside of the tap in the vessel flange. The leak-off line originating from reactor vessel nozzle N14 (N14 leak-off line) has a tap located outside of the second seal ring. For the N13 leak-off line, failure of the inner seal ring is the only condition under which this line is pressurized. The N14 leak-off line requires both seal rings to fail. Therefore, these lines are not expected to be pressurized during normal reactor operation.

The configuration of this piping precludes system leakage testing while the RPV head is removed because the configuration of the vessel taps, coupled with the high test pressure, prevents the taps from having test equipment installed. The N1 3 leak-off line tap has a diameter of 3/16" and the N14 leak-off line tap has a diameter of 1/2". Both taps are smooth walled making the effectiveness of a temporary test connection seal at high pressure

BVY 12-086 / Attachment 1 / Page 2 of 3 limited. Failure of the test connection presents a personnel safety hazard and may result in foreign material entering the reactor vessel.

The configuration also precludes pressurizing the lines with the RPV head installed. The head contains two grooves that hold the seal rings. The seal rings are held in place by a series of retainer clips that are housed in recessed cavities in the flange face. If a system leakage test was performed via the N13 leak-off line, the inner seal ring would be pressurized in a direction opposite its design function. This test pressure would result in a net inward force on the inner seal ring that would tend to push it into the recessed cavity that houses the retainer clips. The thin seal ring material would likely be damaged by the inward force. The same situation exists for the outer seal ring when testing via the N14 leak-off line.

Also, not installing the seal rings in order to perform a system leakage test requires the additional time and radiation exposure associated with the subsequent removal and reinstallation of the RPV head to install the seal rings prior to startup. Purposely failing the seal rings would require purchasing new seal rings in addition to the subsequent removal and reinstallation of the RPV head.

Considering this information, compliance with IWC-5221 will result in undue hardship and unusual difficulty without a compensating increase in the level of quality or safety.

5. Proposed Alternative and Basis for Use In lieu of the requirements of IWC-5221, a VT-2 visual examination will be performed during the next refueling outage in March 2013 on the accessible portions of the affected components. This is the last refueling outage in the fourth inservice inspection (ISI) program interval. The examination will be conducted with the affected components subject to static pressure head with the RPV head removed and the refueling cavity filled to its normal refueling water level for at least four (4) hours. The static head developed with the leak-off lines filled with water will allow for detection of pressure boundary failures.

This proposed alternative is identical to that presented in Code Case N-805. However, this Code Case has not yet been approved by the NRC and is not yet identified in Regulatory Guide 1.147, "In-service Inspection Code Case Acceptability, ASME Section XI, Division 1".

6. Duration of Proposed Alternative This alternative is requested for the remainder of the fourth ISI program interval, which ends on August 31, 2013.

BVY 12-086 / Attachment 1 / Page 3 of 3

7. Precedents (1) Comanche Peak, Unit 1, Relief Request No. C-2 for the Unit 1 Reactor Pressure Vessel Leak-off Flange (Third ISI Interval Start Date: August 13, 2010); submittal, dated August 23, 2012, is under review by NRC; Docket No. 50-445 (ADAMS Accession No. ML12250A670]

(2) LaSalle County Station, Units 1 and 2 - Request for Relief Nos. 13R-03, 13R-04, 13R-08, 13R-09 and 13R-10: Third 10-Year Interval In-service Inspection Program Plan (TAC NOS. MD5459, MD5460, MD5390, MD5463, MD5464, MD5465, MD5466, MD5467, and MD5468); January 30, 2008; Docket Nos. 50-373 and 50-374 [ADAMS Accession No. ML073610587]

(3) Susquehanna Steam Electric Station, Units 1 and 2 - Third 10-Year Inservice Inspection Interval Program Plan (TAC NOS. MC1185, MC1186, MC1191, MC1192, MC1193, MC1194, MC1195, MC1196, MC1197, MC1198, MC1199, MCI200); September 24, 2004; Docket Nos. 50-387 and 50-388 [ADAMS Accession No. ML042680078]

The following precedents pertain to approved relief requests for leak-off lines classified as ASME Code Class 1:

(4) Millstone Power Station, Unit No. 3 - Issuance of Relief Request IR-3-11 Regarding Use of American Society of Mechanical Engineering Code,Section XI, 2004 Edition (TAC No. ME1263); April 29, 2010; Docket No. 50-423 [ADAMS Accession No. ML101040042]

(5) Limerick Generating Station, Units 1 and 2, Evaluation of Relief Requests RR-33, RR-34 and RR-35, Associated with the Second In-service Inspection Interval (TAC Nos.

MD8071, MD8073, MD8074, MD8075, and MD8076); January 27, 2009; Docket Nos.

50-352 and 50-353 [ADAMS Accession No. ML090060218]

(6) Limerick, Units 1 and 2 -- Evaluation of Relief Requests 13R-02, 13R-06, 13R-07, 13R-08, 13R-09, 13R-10, 13R-1 1, 13R-12, Associated with the Third In-service Inspection Interval (TAC Nos. MD5200 and MD5201); March 11, 2008; Docket Nos. 50-352 and 50-353

[ADAMS Accession No. ML080500584]

(7) North Anna Power Station, Unit No's. 1 and 2 Re: ASME Code Third 10-year ISI Program. (TAC No's MC5588, MC5589, MC5590, MC5591, MC5592, MC5593, MC5594, MC5595, MC5599 and MC5600); February 9, 2006; Docket Nos. 50-338 and 50-339 [ADAMS Accession No. ML060450517]

8. Reference Code Case N-805, "Alternative to Class1 Extended Boundary End of Interval or Class 2 System Leakage Testing of the Reactor Vessel Head Flange O-Ring Leak-Detection System," approved by the American Society of Mechanical Engineers (ASME) on February 25, 2011

BVY 12-086 Docket No. 50-271 Attachment 2 Vermont Yankee Nuclear Power Station Reactor Pressure Vessel Head Flange Leak-Off Lines Sketches

BVY 12-086 / Attachment 2 / Page 1 of 2 4

FRESSUM 1--IA

• Reactor Pressure Vessel Head Flange Leak Detection System (From drawing G-191167)

BVY 12-086 / Attachment 2 / Page 2 of 2 Inner Seal Outer Seal Ring (typ.) -* *Ring (typ.)

Detail of Reactor Pressure Vessel Head Flange Leak Detection Taps (From drawing 5920-00327)