ET 14-0019, 10 CFR 50.55a Request 13R-11 for the Third Inservice Inspection Program Interval

10 CFR 50.55a Request 13R-11 for the Third Inservice Inspection Program Interval

ML14182A091
Person / Time
Site:	Wolf Creek
Issue date:	06/26/2014
From:	Reasoner C Wolf Creek
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ET 14-0019
Download: ML14182A091 (8)

Text

1'CREEK OPERATING CORPORATION Cleveland Reasoner June 26, 2014 Vice President Engineering ET 14-0019 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

Subject:

Docket 50-482: 10 CFR 50.55a Request 13R-11 for the Third Inservice Inspection Program Interval Gentlemen:

Pursuant to 10 CFR 50.55a(a)(3)(ii), Wolf Creek Nuclear Operating Corporation (WCNOC) hereby requests Nuclear Regulatory Commission (NRC) approval of 10 CFR 50.55a Request Number 13R-1 1 for the Third Ten-Year Interval of WCNOC's Inservice Inspection (ISI) Program.

The Attachment provides 10 CFR 50.55a Request 13R-11, which requests relief from the Pressure Test Requirements of ASME Section Xl IWC-5220.

Performance of the proposed alternative pressure testing of this Request will be performed in Refueling Outage 20, which begins February 28, 2015. Therefore, approval is requested by March 6, 2015.

This letter contains no commitments. If you have any questions concerning this matter, please contact me at (620) 364-4171, or Mr. Michael J. Westman at (620) 364-4009.

Sincerely, Cleveland Reasoner COR/rlt Attachment ACQ-7 P.O. Box 411 / Burlington, KS 66839 / Phone: (620) 364-8831

ýJile An Equal Opportunity Employer M/F/HCNET

ET 14-0019 Page 2 of 2 cc: M. L. Dapas (NRC), w/a C. F. Lyon (NRC), w/a N. F. O'Keefe (NRC), w/a Senior Resident Inspector (NRC), w/a

Attachment to ET 14-0019 Page 1 of 5 Wolf Creek Nuclear Operating Corporation 10 CFR 50.55a Request 13R-11 Request for Relief from the Pressure Test Requirements of ASME Section Xl IWC-5220

Attachment to ET 14-0019 Page 2 of 5 10 CFR 50.55a Request 13R-11 Request for Relief from the Pressure Test Requirements of ASME Section Xl IWC-5220 Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(ii)

Hardship or Unusual Difficulty Without Compensating Increase in Level of Quality or Safety

1.0 ASME Code Components Affected

The affected components are the Wolf Creek Generating Station (WCGS) ASME Code Class 2 piping and components in the reactor vessel flange leak-off lines connected to the Reactor Pressure Vessel running to isolation valve BBHV8032. The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code, Section Xl (Reference 1) examination category and item number covering the required examination and testing are IWC-2500-1, Examination Category C-H, Item No. C7.10.

A marked-up drawing that shows the configuration of piping is included in Attachment 1 to this Request.

2.0 Applicable Code Edition and Addenda ASME BPV Code Section XI, 1998 Edition through 2000 Addenda 3.0 Applicable Code Requirement ASME Section Xl, paragraph IWC-5221, states "The system leakage test shall be conducted at a 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)."

ASME Section XI, subparagraph IWC-5222(a), states "The pressure retaining boundary includes only those portions of the system required to operate or support the safety function up to and including the first normally closed valve (including a safety or relief valve) or valve capable of automatic closure when the safety function is required."

4.0 Reason for Request Nuclear Regulatory Commission (NRC) Information Notice 2014-02, Failure to Properly Pressure Test Reactor Vessel Flange Leak-Off Lines, (Reference 2) was issued on February 25, 2014. It provided examples of instances where licensees did not perform, or inadequately performed, system pressure tests of reactor vessel flange leak-off lines.

Attachment to ET 14-0019 Page 3 of 5 Wolf Creek Nuclear Operating Corporation (WCNOC) has determined that a similar situation exists at WCGS and has entered this condition into its corrective action program; investigation has additionally determined that a similar request for alternative testing is appropriate, which results in this Request.

The following discussion provides the basis for the requested relief and NRC approval of the proposed alternative testing in accordance with 10 CFR 50.55a(a)(3)(ii) because complying with ASME Section XI, Subsection IWC-5221 Code requirements would result in a hardship or unusual difficulty to the station without a compensating increase in the level of quality and safety.

The ASME Code Section Xl, 1998 Edition through 2000 Addenda requires that Class 2 pressure boundary piping shall be pressure tested once each inspection period. The reactor vessel flange seal leak detection piping is separated from the reactor coolant pressure boundary by a metallic O-ring seal. The pressure openings for the leak detection piping are located on the vessel flange mating surface. The inboard pressure opening is located between the inner and outer O-rings. The outboard pressure opening is located on the outboard side of the outer O-ring in the vessel flange. Failure of the inner O-ring is the only condition under which the reactor vessel flange leak-off line could be pressurized to any significant pressure. Therefore, the reactor vessel flange leak-off line is not expected to be pressurized during the system pressure test following a refueling outage or during normal operation. The leak-off line located outboard of the outer O-ring is outside of both O-ring sealing boundaries. The isolation valve for the outboard leak-off line, BBV0079, is normally closed. The isolation valve for the inboard leak off-line between the two O-rings, BBV0080, is normally open during plant operations.

The configuration of this piping poses personnel and equipment safety concerns if pressure testing is performed at Reactor Coolant System (RCS) operating pressure:

" Plugs would need to be installed in the reactor vessel flange face to act as a pressure boundary for each test, and then removed after the test.

" The installation of the plugs and subsequent use would incur additional radiological dose due to additional time for personnel at the reactor vessel flange.

" The plugs would also present a foreign material exclusion issue for the handling of a very small diameter plug over the reactor vessel that would be required to be installed to complete a leakage test at pressure.

• The use of an alternative test rig to test those isolated portions of piping to full RCS operating pressure would have to include application of a compatible pressurized medium. This would result in personnel stationed near pressurized vent or drain valves, exposing them to unnecessary personal safety hazards in the event of a leak from the non-class test pressure rig connections. A break at any connection of the rig under such conditions (temporary non-code connections under RCS test pressure) would pose a substantial personnel safety hazard.

The configuration also precludes pressurizing the line externally with the head installed.

The closure head contains two concentric grooves that hold the inner and outer O-rings.

Attachment to ET 14-0019 Page 4 of 5 The O-rings are held in place by a series of retainer clips that are housed in recessed cavities in the flange face. If a pressure test were to be performed with the head installed, the O-ring would be pressurized in a direction opposite to its design function.

This test pressure would result in a net inward force on the inner O-ring that would tend to push it into the recessed cavity that houses the retainer clips. The thin O-ring material could be damaged by the inward force.

5.0 Proposed Alternative and Basis for Use WCNOC proposes to use reduced pressure testing as an alternative for the Code required pressure. The basis for the alternative testing is described below. The pressure tests and VT-2 examinations performed at the lower pressures (as an alternative to the pressure requirement in ASME Section Xl, paragraph, IWC-5221) provide an acceptable level of assurance of the leakage integrity and operational readiness of the tested piping.

The proposed alternative to the System Leakage Test requirements of ASME Section Xl, Table IWC-2500-1, Examination Category C-H, Item No. C7.10, and ASME Section Xl, paragraph, IWC-5221, is to perform a VT-2 visual examination of the accessible areas of the leak detection system piping while the system is subjected to the static pressure from the head of water when the reactor cavity is filled to its normal refueling water level, 23 feet of water or greater, for at least four hours.

During the operating cycle if the inner O-ring should leak it will be identified by an increase in temperature of the leak-off line above ambient temperature. This leak detection piping has a temperature indication and a high temperature alarm in the Control Room, which is monitored by the operator. This piping also acts as a leak-off line to collect leakage which is routed to the Reactor Coolant Drain Tank.

Additionally, the reactor vessel flange leak detection piping would only function as a Class 2 pressure boundary if the inner O-ring fails; thereby, pressurizing the line. If any significant pipe through-wall leakage were to occur in the leak detection piping during this time of pressurization, it would exhibit boric acid accumulation that would be identified by the boron trace residue during the VT-2 visual examination to be performed as proposed in this request. The reactor vessel flange leak-off lines are also VT-2 examined during the RCS Pressure Test at the end of each refueling outage for indications of leakage.

The proposed alternative testing will be performed by WCNOC in the Third Inservice Inspection (ISI) Interval for WCGS. The leak-off lines have been pressurized during each previous refueling outage similar to the proposed alternative testing identified in this Request but have not been credited for Code compliance. Subject to NRC approval of the proposed alternative testing in this Request, the proposed alternative testing will be performed and credited in Refueling Outage 20.

6.0 Duration of Proposed Alternative Relief is requested for the remainder of the Third Ten-Year ISI Interval, which ends on September 2, 2015. Implementation of the alternative testing will be performed during

Attachment to ET 14-0019 Page 5 of 5 Refueling Outage 20, which is the last refueling outage of the Third Ten-Year ISI Interval.

7.0 Precedents NRC letter from M.T. Markley, USNRC, to R.K. Edington, Arizona Public Service, "Palo Verde Nuclear Generating Station, Units 1, 2, and 3 - Request for Relief from the American Society of Mechanical Engineers (ASME) Code, Section Xl Requirements Regarding the Reactor Vessel Head Flange Seal Leak Detection Piping (TAC Nos.

MF0447, MF0448, and MF0449)," April 4, 2013. ADAMS Accession No. ML13085A254.

NRC letter from M.T. Markley, USNRC, to Vice President Operations, Entergy Operations, Inc., "Arkansas Nuclear One, Unit 2 - Request for Relief ANO2-ISI-015 from American Society of Mechanical Engineers (ASME) Code, Section Xl, for Periodic Pressure Sealing Requirements on the Reactor Vessel Flange Leak Detection Piping (TAC No. MF0941)," June 27, 2013. ADAMS Accession No. ML13161A241.

NRC letter from M.T. Markley, USNRC, to R. Flores, Luminant Generation Company LLC, "Comanche Peak Nuclear Power Plant, Unit 2 - Request for Relief from Pressure Test Requirements on Reactor Pressure Vessel Flange Leak-off Piping for the Second 10-year Inservice Inspection Interval (TAC No. MF2997)," April 4, 2014. ADAMS Accession No. ML14084A291.

8.0 References

1. ASME Boiler and Pressure Vessel Code, Section Xl, 1998 Edition through 2000 Addenda, American Society of Mechanical Engineers, New York.

2. NRC Information Notice 2014-02: "Failure to Properly Pressure Test Reactor Vessel Flange Leak-Off Lines," February 25, 2014.

9.0 Attachments The boundaries of the portion of Class 2 piping and components covered in this Request are indicated in Attachment 1, which is a marked-up extraction from the applicable piping and instrumentation drawing.

to 10 CFR 50.55a Request 13R-11 Page 1 of 1

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