DCL-10-157, Snubber Visual Examination and Functional Testing Related to the Inservice Inspection Program Third 10-Year Interval

Snubber Visual Examination and Functional Testing Related to the Inservice Inspection Program Third 10-Year Interval

ML103560316
Person / Time
Site:	Diablo Canyon
Issue date:	12/21/2010
From:	Becker J Pacific Gas & Electric Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
PG&E Letter DCL-10-157
Download: ML103560316 (6)

Text

Pacific Gas and Electric Company James R. Becker Diablo Canyon Power Plant Site Vice President Mail Code 104/5/ 601

p. o. Box 56 Avila Beach, CA 93424 805.545.3462 Internal: 691.3462 December 21,2010 Fax: 805.545.6445 PG&E Letter DCL-1 0-157 10 CFR 50. 55a u.s. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Power Plants (DCPP) Units 1 and 2 Snubber Visual Examination and Functional Testing Related to the Inservice Inspection Program Third 10-Year Interval

Dear Commissioners and Staff:

The purpose of this letter is to document PG&E's intent to comply with the requirements of 10 CFR 50.55a(b)(3)(v) for snubber visual examination and functional testing for the remainder of the inservice inspection program third 10-year interval, in lieu of utilizing Relief Request NDE-SBR, approved by the NRC by letter dated February 25,2009 (ADAMS Accession No. ML090210691). The third 10-year interval began January 1, 2006, for Unit 1 and July 1, 2006, for Unit 2.

Pursuant to 10 CFR 50.55a, PG&E will perform snubber visual examination and functional testing in accordance with the ASME OM Code to include the 2001 Edition with 2003 Addenda. Paragraph 50.55a(b)(3)(v) allows Subsection ISTD, "Preservice and Inservice Examination and Testing of Dynamic Restraints (Snubbers) in Light-Water Reactor Nuclear Power Plants," to be used in place of the requirements for snubbers in ASME Section XI, IWF-5200(a) and (b) and IWF-5300(a) and (b), by making appropriate changes to technical specifications or licensee-controlled documents with the additional provision that examinations must be performed using the VT-3 visual examination method described in ASME Section XI, Article IWA-2213.

DCPP Equipment Control Guideline (ECG) 99.1, "Snubbers," has been revised, effective September 15, 2010, to require performance of snubber visual examinations and functional testing in accordance with the requirements of SUbsectio'n ISTD. A snubber visual examination and testing program plan is enclosed.

In addition, PG&E will also utilize Code Case OMN-13 "Requirements for Extending Snubber Inservice Visual Examination Interval at LWR Power Plants." This Code Case has been approved unconditionally for. use in Regulatory Guide 1.192, "Operation and Maintenance Code Case Acceptability."

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Comanche Peak

• Diablo Canyon

• Palo Ve r de

• San Onofre

• South Te x as Project

• Wolf Creek

Document Control Desk PG&E Letter DCL-10-157 December 21,2010 Page 2 If you have any questions or require additional information, please contact Tom Baldwin at (805) 545-4720.

Sincerely, cc: Diablo Distribution cc/enc: Elmo E. Collins, Regional Administrator, NRC Region IV Michael S. Peck, NRC Senior Resident Inspector Alan Wang, Project Manager, Office of Nuclear Reactor Regulation State of California, Pressure Vessel Unit A member of the STARS (Strategic Teaming and Resource Sharing) Allian c e Callaway

• Comanche Peak

• Diablo Canyon

• Palo Verde

• San Onofre

• South Texas Project

• Wolf Creek

Enclosure PG&E Letter DCL-10-157 Third Interval Snubber Program Diablo Canyon Power Plant

1.0 General

1.1 In order to ensure the required operability of all safety-related snubbers for both Diablo Canyon Power Plant (DCPP) Units 1 and 2 during a seismic or other event, initiating dynamic loads, the inspection and testing of these snubbers shall be implemented and performed in accordance with the requirements of Equipment Control Guideline (ECG) 99.1, "Snubbers."

1.2 The Snubber Program, as defined within ECG 99.1, establishes visual examination, functional testing and service life monitoring requirements, pertaining to mechanical and hydraulic safety-related snubbers.

1.3 The examination boundaries shall include the snubber assembly from pin to pin inclusive. Coordination with the Inservice Inspection Program Owner will be required to complete the surveillance requirements for piping and structural attachments.

1.4 The Snubber Program described in ECG 99.1 adheres to the requirements of the ASME OM Code, Subsection ISTD, 2001 Edition with 2003 addenda, as allowed by 10 CFR 50.55a(b)(3)(v) in lieu of ASME Section XI, IWF-5200(a) and (b) and IWF-5300(a) and (b).

1.5 Surveillance Test Procedure M-78B, in conjunction with ECG 99.1, includes a snubber service life monitoring program for hydraulic and mechanical snubbers that adheres to the requirements of ISTD-6000.

2.0 Examination, Testing and Service Life Monitoring Requirements:

2.1 Visual examinations and functional testing shall be performed to the extent specified within ECG 99.1.

2.2 Snubbers are currently grouped into defined test plan groups (DTPG) by design type, in accordance with ISTD-5252 for testing purposes. (Sample selection will follow the 10 percent sampling plan described in ISTD-5300.)

The groups at DCPP are as listed below:

Snubber Design Unit 1 Unit 2 Type DTPG Includes DTPG Includes AD40, AD70, AD40, AD70, AS AS AD150 AD150 Anchor Darling AM AD500 AM AD500 AL AD1600, AD 5500, AL AD1600, AD 1

Enclosure PG&E Letter DCL-10-157 Snubber Design Unit 1 Unit 2 Type DTPG Includes DTPG Includes AD12500 5500, AD12500 PS 1/4, 1/2 PS 1/4, 1/2 Basic PSA PM 1, 3, 10 PM 1, 3, 10 PL 35, 100 PL 35, 100 Paul Munroe M 20x3 LG Bore M 20x3 LG Bore Grinnell/Anvil G/A All Sizes G All Sizes (Hydraulic) 2.3 The service life of all snubbers shall be monitored and snubbers replaced or regreased as required to ensure that the service life is not exceeded between surveillance inspections during a period when the snubber is required to be operable. The replacement or regreasing shall be documented and records retained in accordance with DCPP procedures.

3.0 Examination and Testing Methods:

3.1 Visual examinations shall be performed by qualified individuals using the VT-3 method as described in ASME Section XI, IWA-2213. Visual examinations and functional testing shall be performed to verify the requirements specified within ECG 99.1 are met in accordance with Subsection ISTD.

4.0 Examination and Testing Frequency:

4.1 Visual examinations and functional testing shall be performed at the frequency specified within ECG 99.1. DCPP currently performs accessible and inaccessible snubber visual examinations during alternating refueling outages, which results in approximately one half of the snubber population being examined during each refueling outage.

4.2 Visual (VT-3) examinations shall be performed whenever new snubbers are installed, reinstallation of existing or swapped snubbers that were functionally tested, or after repairs, replacements or modifications.

4.3 Functional testing requirements for new installations or spares shall be equal to or more stringent than that specified within ECG SR 99.1.

5.0 ASME OM Code Case, OMN-13:

5.1 Code Case OMN-13, which allows the extension of the visual examination interval, will be implemented for snubber inspections during this interval.

Code Case OMN-13 is approved for use by the NRC in Regulatory Guide 1.192 (June 2003).

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Enclosure PG&E Letter DCL-10-157 5.2 DCPP will continue to perform accessible and inaccessible snubber visual examinations separately, which results in approximately one half of the snubber population for each Unit being examined during a campaign.

However, the interval will be extended as allowed by Code Case OMN-13 for each group, accessible and inaccessible.

6.0 Examination, Testing and Service Life Monitoring Evaluation:

6.1 Snubbers that do not appear to conform to the visual examination requirements of ECG 99.1, shall be reported for evaluation and appropriate corrective action.

6.2 Snubbers that do not appear to conform to the visual examination acceptance requirements and are later confirmed as operable as a result of functional testing may be declared operable for the purpose of establishing the next visual inspection interval, providing that the unacceptable condition did not affect operational readiness.

6.3 Snubbers that do not meet the operability testing acceptance criteria in ECG 99.1 shall be evaluated to determine the cause of the failure and appropriate corrective action taken.

6.4 The service life of a snubber is evaluated using manufacturing input and engineering information gained through consideration of the snubber service conditions and inservice functional test results. A service life monitoring program is included in ECG 99.1 and Surveillance Test Procedure M-78B.

7.0 Repair, Replacement and Modification Requirements:

7.1 Repairs, Replacements and Modifications performed on snubbers under this program shall conform, as applicable, to the requirements specified within the ASME Code,Section XI.

8.0 Scheduling

8.1 The visual examinations and functional testing schedules shall be established, tracked and maintained within the Snubber Testing Program.

8.2 The Snubber Program Owner shall identify and track expanded or additional testing and/or examinations as required by ECG 99.1 and Subsection ISTD.

9.0 Reports and Records:

9.1 Reports and records for snubber visual examinations and functional testing shall be maintained for all snubbers included within the Snubber Program.

9.2 Applicable records and reports, as required for repair and replacements, 3

Enclosure PG&E Letter DCL-10-157 shall be maintained for snubbers.

9.3 Records of the service life of all hydraulic and mechanical snubbers listed in this program, including the date at which the service life commences or expires, and associated installation and maintenance records will be maintained.

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