ML081300408

Relief Request No. RV-07, Alternate to the ASME OM Code 5-Year Test Interval for Main Steam Safety Relief Valves - Pilgrim Nuclear Power Station

ML081300408
Person / Time
Site:	Pilgrim
Issue date:	05/27/2008
From:	Mark Kowal NRC/NRR/ADRO/DORL/LPLI-1
To:	Entergy Nuclear Operations
kim J, NRR/ADRO/DORL, 415-4125
References
TAC MD8526
Download: ML081300408 (12)

Text

May 27, 2008 Vice President, Operations Entergy Nuclear Operations, Inc.

Pilgrim Nuclear Power Station 600 Rocky Hill Road Plymouth, MA 02360-5508

SUBJECT:

RELIEF REQUEST NO. RV-07, ALTERNATE TO THE ASME OM CODE 5-YEAR TEST INTERVAL FOR MAIN STEAM SAFETY RELIEF VALVES -

PILGRIM NUCLEAR POWER STATION (TAC NO. MD8526)

Dear Sir or Madam:

By letter dated April 16, 2008 (Agencywide Documents and Management System (ADAMS)

Accession No. ML081150716), Entergy Nuclear Operations, Inc. (the licensee) submitted Relief Request (RR) No. RV-07 for the Fourth 10-Year Interval Inservice Testing (IST) Program at Pilgrim Nuclear Power Station (PNPS). The licensee requested relief from certain IST requirements of the American Society of Mechanical Engineers Code for Operation and Maintenance of Nuclear Power Plants (ASME OM Code). The RR involves an extension to the ASME OM Code 5-year test interval for pressure relief devices in light water reactor power plants.

Based on the information provided in the RR, the Nuclear Regulatory Commission (NRC) staff concluded that the licensees compliance to the ASME OM Code requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

Therefore, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(a)(3)(ii), the NRC staff authorizes the IST program alternative proposed in RR, RV-07, for the fourth 10-year IST interval for Pilgrim. The proposed alternative provides reasonable assurance that the component is operationally ready.

The requested duration of the RR is 11 months for the affected Main Steam Safety Valve (MSSV). The licensee stated that the compliance with the applicable requirements of the ASME OM Code for the one MSSV, prior to refueling outage 17 is not practical, in that the evolution would result in an unnecessary plant shutdown, unnecessary challenges to safety systems, and unnecessary cycling of equipment, all without a compensating increase in the level of quality or safety. The results of the staffs review are provided in the enclosed safety evaluation.

If you have any questions regarding this approval, please contact the Pilgrim Project Manager, James Kim, at 301-415-4125.

Sincerely,

/RA/

Mark G. Kowal, Chief Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-293

Enclosure:

As stated cc w/encl: See next page

If you have any questions regarding this approval, please contact the Pilgrim Project Manager, James Kim, at 301-415-4125.

Sincerely,

/RA/

Mark G. Kowal, Chief Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-293

Enclosure:

As stated cc w/encl: See next page Docket No. 50-293

Enclosure:

As stated cc w/encl: See next page DISTRIBUTION:

PUBLIC RPowell, RI RidsOgcMailCenter JMcHale RidsNrrDorlLpl1-1 SLittle JKim GHill (2) WPoertner RidsAcrsAcnw&mMail center Amendment No.: ML081300408 *See memo dated May 09, 2008 OFFICE LPLI-1/PM LPLI-1/LA CSGB/BC OGC LPL1-1/BC NAME JKim SLittle JMcHale

• JBielecki MKowal DATE 05/12/2008 05/12/2008 05/09/2008 5/21/08 5/27/08 OFFICIAL RECORD COPY

Pilgrim Nuclear Power Station cc:

Regional Administrator, Region I U. S. Nuclear Regulatory Commission 475 Allendale Road Massachusetts Emergency King of Prussia, PA 19406-1415 Management Agency Attn: John Giarrusso, Senior Resident Inspector Nuclear Preparedness Manager U. S. Nuclear Regulatory Commission 400 Worcester Road Pilgrim Nuclear Power Station Framingham, MA 01702-5399 Post Office Box 867 Plymouth, MA 02360 Mr. William D. Meinert Nuclear Engineer Chairman, Board of Selectmen Massachusetts Municipal Wholesale 11 Lincoln Street Electric Company Plymouth, MA 02360 P.O. Box 426 Ludlow, MA 01056-0426 Chairman Nuclear Matters Committee Site Vice President Town Hall Entergy Nuclear Operations 11 Lincoln Street Pilgrim Nuclear Power Station Plymouth, MA 02360 600 Rocky Hill Road Plymouth, MA 02360-5508 Chairman, Duxbury Board of Selectmen Town Hall General Manager, Plant Operations 878 Tremont Street Entergy Nuclear Operations Duxbury, MA 02332 Pilgrim Nuclear Power Station 600 Rocky Hill Road Office of the Commissioner Plymouth, MA 02360-5508 Massachusetts Department of Environmental Protection Director, Nuclear Safety Assurance One Winter Street Entergy Nuclear Operations Boston, MA 02108 Pilgrim Nuclear Power Station 600 Rocky Hill Road Office of the Attorney General Plymouth, MA 02360-5508 One Ashburton Place 20th Floor Manager, Licensing Boston, MA 02108 Entergy Nuclear Operations Pilgrim Nuclear Power Station MA Department of Public Health 600 Rocky Hill Road Radiation Control Program Plymouth, MA 02360-5508 Schrafft Center, Suite 1M2A 529 Main Street Charlestown, MA 02129

Pilgrim Nuclear Power Station cc:

Senior Vice President Senior Manager, Nuclear Safety & Licensing Entergy Nuclear Operations, Inc. Entergy Nuclear Operations, Inc.

P.O. Box 31955 P.O. Box 31955 Jackson, MS 39286-1995 Jackson, MS 39268-1995 Vice President, Oversight Assistant General Counsel Entergy Nuclear Operations, Inc. Entergy Nuclear Operations P.O. Box 31995 440 Hamilton Avenue Jackson, MS 39286-1995 White Plains, NY 10601 Senior Vice President and COO Ms. Stacey Lousteau Entergy Nuclear Operations, Inc. Treasury Department 440 Hamilton Avenue Entergy Services, Inc.

White Plains, NY 10601 639 Loyola Avenue New Orleans, LA 70113 Vice President, Operations Entergy Nuclear Operations, Inc. Mr. James Sniezek Pilgrim Nuclear Power Station 5486 Nithsdale Drive 600 Rocky Hill Road Salisbury, MD 21801-2490 Plymouth, MA 02360-5508 Mr. Michael D. Lyster Mr. Michael Kansler 5931 Barclay Lane President & CEO/CNO Naples, FL 34110-7306 Entergy Nuclear Operations, Inc.

P.O. Box 31955 Mr. Garrett D. Edwards Jackson, MS 39268-1995 814 Waverly Road Kennett Square, PA 19348 Mr. John F. McCann Director, Nuclear Safety & Licensing Mr. John Doering Entergy Nuclear Operations, Inc. P.O. Box 189 440 Hamilton Avenue Parker Ford, PA 19457 White Plains, NY 10601

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR RELIEF NO. RV-07 ENTERGY NUCLEAR OPERATIONS, INC.

PILGRIM NUCLEAR POWER STATION DOCKET NO. 50-293

1.0 INTRODUCTION

By letter dated April 16, 2008 (Agencywide Documents and Management System (ADAMS)

Accession No. ML081150716), Entergy Nuclear Operations, Inc. (the licensee) submitted Relief Request (RR) No. RV-07 for the Fourth 10-Year Interval Inservice Testing (IST) program at Pilgrim Nuclear Power Station (PNPS). The licensee requested relief from certain IST requirements of the 1995 Edition through 1996 Addenda of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code).

The Pilgrim Fourth 10-Year IST Interval commenced in December 2002. The RR involves an extension to the ASME OM Code 5-year test interval for pressure relief devices in light-water reactor power plants.

2.0 REGULATORY EVALUATION

Title 10 of the Code of Federal Regulations (10 CFR) 50.55a, requires that IST of certain ASME Code Class 1, 2, and 3 pumps and valves be performed at 120-month (10-year) IST program intervals in accordance with the specified ASME Code and applicable addenda incorporated by reference in the regulations, except where alternatives have been authorized or relief has been requested by the licensee and granted by the Nuclear Regulatory Commission (NRC) pursuant to paragraphs (a)(3)(i), (a)(3)(ii), or (f)(6)(i) of 10 CFR 50.55a. In accordance with 10 CFR 50.55a(f)(4)(ii), licensees are required to comply with the requirements of the latest edition and addenda of the ASME Code incorporated by reference in the regulations 12 months prior to the start of each 10-year IST program interval. In accordance with 10 CFR 50.55a(f)(4)(iv),

Inservice tests of pumps and valves may meet the requirements set forth in subsequent editions and addenda that are incorporated by reference in 10 CFR 50.55a(b), subject to the limitations and modifications listed in paragraph (b) and NRC approval. Section 50.55a(f)(4)(iv) also provides that Portions of editions or addenda may be used provided that all related requirements of the respective editions or addenda are met. In proposing alternatives or requesting relief, the licensee must demonstrate that: (1) the proposed alternatives provide an acceptable level of quality and safety; (2) compliance would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety; or (3) conformance is impractical for the facility. Section 50.55a authorizes the NRC to approve alternatives and to Enclosure

grant relief from ASME OM Code requirements upon making necessary findings. NRC guidance contained in Generic Letter (GL) 89-04, Guidance on Developing Acceptable Inservice Testing Programs, provides alternatives to ASME Code requirements which are acceptable. Further guidance is given in GL 89-04, Supplement 1, and NUREG-1482 Revision 1, Guidance for Inservice Testing at Nuclear Power Plants.

The NRC staffs findings, with respect to granting or denying the IST program RR, are given below:

3.0 TECHNICAL EVALUATION

3.1 Valve Relief Request RV-07 3.1.1 Code Requirements The licensee requested relief from Appendix I, Section I-1.3.3 of ASME OM, which requires that a minimum of 20 percent of the valves from each group be tested within any 24-month interval and that the test interval for any individual valve shall not exceed 5 years. Relief was requested for Main Steam Safety Valve (MSSV) serial number BK 6302 installed in location RV-203-4A.

3.1.2 Licensees Basis for Requesting Relief (as stated by licensee) 10 CFR 50.55a(f)(4) directs licensees to meet inservice testing requirements for ASME Code Class 1 valves set forth in the ASME OM Code and addenda. The fourth 10-year IST interval for PNPS is based on the 1995 Edition through 1996 Addenda of the ASME OM Code, and specifically Appendix I of the OM Code.

The ASME OM Code, Subsection ISTC, Section ISTC 3.2, states that Inservice testing in accordance with this subsection shall commence when the valves are required to be operable to fulfill their required function(s). The ASME OM Code, Appendix I, Section I-1.3.3 states that Class 1 pressure relief valves shall be tested at least once every 5 years, starting with initial electric power generation. This section also states that the test interval for any individual valve shall not exceed 5 years.

The required test ensures that the MSSV, which is located on the A main steam line between the reactor vessel and the first isolation valve within the drywell, will open at the pressures bounded by the safety analysis.

Compliance with the applicable requirements of the ASME OM Code for MSSV

[RV-203-4A], prior to refueling outage 17 (RFO-17) is not practical, in that the evolution would result in an unnecessary plant shutdown, unnecessary challenges to safety systems, and unnecessary cycling of equipment, all without a compensating increase in the level of quality or safety.

Entergy currently replaces one (out of 2) MSSV at PNPS every refueling outage, so that all valves are removed and tested every two refueling outages. This methodology supports the ASME OM Code requirements for testing previously untested Class 1 pressure relief valves. After each valve is removed and as-found tested, the MSSVs are refurbished to a like-new condition, and reset to an as-left value of plus or minus 1%.

Entergy utilizes Wyle laboratories to perform as-found and as-left testing, and test inspection of the PNPS MSSVs. Entergy utilizes Dresser, Inc. for the valve disassembly, refurbishment, and part inspections for the Pilgrim MSSVs. Both Wyle and Dresser are qualified and approved Pilgrim vendors for the respective tasks that they perform.

Pilgrim procedures require that the safety valve with the earliest service date be removed for testing each RFO. Since there are only 2 safety valves installed, this means that the longest any safety valve can be installed in the plant without testing is 2 cycles (48 months). During the following cycle, the valve is as-found tested by Wyle, disassembled, inspected, and reassembled by Dresser, and re-certified by Wyle for installation during the next RFO. When the re-certification is completed early in the cycle (so the valve will be available as a spare), the valve test-to-test interval may exceed 60 months; but is always less than 72 months.

The valve is disassembled, inspected, and reassembled in accordance with the Dresser Repair Plan and Report for Model 3700 Series Safety Valves. The repair plan identifies the critical dimensions that are required to be measured during the inspection, and the critical components that are required to be inspected and verified as acceptable for wear and defects. If any components are found to be worn or outside the specified tolerances, they are refurbished to meet these required tolerances, or the applicable part is replaced.

The valve is then re-assembled and certified by performing a minimum of two consecutive lifts within 1% of the valves nameplate set pressure. The certified as-left set point is typically set to within 1/2% of the valves nameplate set pressure.

As part of a review of the PNPS IST program with respect to a recent ASME OM Code interpretation, Entergy identified a discrepancy relative to the 5-year test interval. The ASME OM Code interpretation (i.e., ASME Code Interpretation 01-18 from the ASMEOM code, 2004 Edition) indicated that implementation of the 5-year test interval should be based upon a test-to-test duration. The historical method used at Pilgrim with respect to MSSV test intervals has been to use an installation-to-test duration, and to ensure that all installed MSSVs would not exceed a 5-year testing frequency.

According to the licensee, both MSSVs will be replaced and tested during RFO-17, which is scheduled to begin in April 19, 2009. MSSV RV-203-4A is currently scheduled to be replaced during RFO-17. The replacement and test schedule is consistent with the historical Entergy method for implementing OM Code, Appendix I requirements (i.e., the valves will have been installed for less than or equal to two operating cycles). However, utilizing a test-to-test interpretation, the 5-year interval for MSSV RV-203-4A will have been exceeded (by approximately 11 months) prior to beginning RFO-17.

3.1.3 Licensees Basis for Use (as stated by licensee)

IST history for MSSVs at PNPS from 1987 to the present indicates that the results for all of the tests (7 total), conducted on MSSVs that have been installed for two operating cycles (i.e., 48 months) have successfully passed the ASME OM Code as-found acceptance criteria of plus or minus 3%. Furthermore, historical test data indicates that 3 of the 7 tests remained within the as-found Technical Specification (TS) tolerance of plus or minus 1%. Finally, the as-found test data for the other 4 MSSVs that lifted outside the TS 1% tolerance showed that 3 of the valves exceeded the acceptance criteria in the

negative or conservative direction. The one MSSV that exceeded the TS acceptance criterion in the positive direction was found to be above the TS specified 1% tolerance by 8 psig.

IST history, for MSSV serial number BK 6302, for which relief is being requested, from 1990 to the present all of the tests (3 total) for which this MSSV was installed for two operating cycles (i.e., 48 months) successfully passed the ASME OM Code as-found acceptance criteria of plus or minus 3%. Historical test data also indicated that 2 of the 3 tests remained within the TS tolerance of plus or minus 1%. The one test that lifted outside the 1% tolerance showed that the valve exceeded the acceptance criteria in the conservative direction; the valve lifted one pound below the 1% acceptance band.

Moreover, a fourth test of the MSSV occurred after it had been installed for 1.3 years.

Prior to this installation, the valve was stored for 1.6 years. After it was removed, it was stored for an additional 3.9 years prior to the as-found testing (a total test-to-test time of 6.8 years). The as-found test was 4 psig high (0.32%) which is within the 1% TS tolerance.

The Entergy data analysis also indicates that the test data is consistent with other industry data for this model MSSVs, including Quad Cities Nuclear Power Station, Units 1 & 2 and Dresden Nuclear Power Station, Units 1 & 2. Additionally, PNPS personnel have indicated that station experience with Dresser Model 6-3777QA MSSVs has been reliable and consistent, and recalled no failures exceeding the OM Code as-found acceptance criteria of plus or minus 3% since the early 1980s.

Entergy has reviewed the historical MSSV vendor Technical Information Program Manual to identify any operating and/or maintenance experience with Model 6-3777QA valves that could provide additional insights regarding the impact of controlled environment storage upon MSSVs. This review indicated that the Dresser 3777Q MSSVs should be stored in a controlled environment, inside specially designed metal containers prior to installation as replacement MSSVs. The vendor recommendations also specify that the controlled environment in which these MSSVs would be stored not be subject to thermal cycling or vibration (i.e., the normal operating conditions to which MSSVs are subjected).

Entergy complies with these vendor recommendations for valve storage. The test certified valves are stored with robust foreign material exclusion barriers installed on the valve inlet and outlet ports, in areas that meet Level B storage requirements at both Wyle Labs and Pilgrim Station. The tested valves are normally stored in sealed metal containers (they may be stored out of the metal container on the shop floor in a controlled area at Wyle Labs while they await shipment), in the upright position. At Pilgrim, the valves are normally stored in the Reactor Building. At both locations, the valves are maintained in environments that are well within the temperature limits specified by the vendor for extended storage.

Finally, the MSSV vendor (Dresser, Inc) has indicated to other industry users (i.e., Plants within the Exelon Generating Company) of the Model 3777Q valve that, in general, there is no degradation in an MSSV when properly stored in a controlled environment for approximately 5 years.

3.1.4 Licensees Proposed Alternative Testing MSSV serial number BK 6302 installed in location RV-203-4A will be removed and tested during RFO-17, along with the remaining other MSSV that will not have exceeded the 5-year test requirement by RFO-17.

3.1.5 Staff Evaluation of Relief Request RV-07 The NRC staff has reviewed the licensees basis and use for relief to determine if it is acceptable to extend the test interval for MSSV serial number BK 6302 installed in location RV-203-4A beyond the allowable 5-year interval specified in the ASME OM Code. Under the proposed alternative, the test interval will be extended approximately 11 months until RFO-17 on a one time basis. The alternative provides that the valve will be removed and tested along with the other remaining MSSV that will not have exceeded the 5-year interval specified by the OM Code.

Both valves will have been installed in the Unit for a maximum of 48 months, and MSSV serial number BK 6302 installed in location RV-203-4A, was in storage for 221/2 months prior to installation.

According to the licensee, the ASME Code does not require that MSSVs be routinely refurbished but refurbishment every two operating cycles provides reasonable assurance that setpoint drift will be minimized. The licensees test history for MSSV serial number BK 6302 from 1990 to the present indicates that all of the tests (3 total) for this MSSV in which it was installed for two operating cycles did not exceed the plus 1% upper acceptance criteria of the TS. One of the three tests lifted one pound below the minus 1% lower acceptance criteria of the TS, which is conservative with respect to overpressure mitigation. The licensees fourth test of MSSV serial number BK 6302 occurred after it had been installed 1.3 years. Prior to this installation, the valve had been stored for 1.6 years. After the valve was removed it was stored for an additional 3.9 years prior to as-found testing (a total test-to-test time of 6.8 years). The licensees as-found test was within the plus or minus 1% TS criteria.

According to the licensee, the testing history for all MSSVs at Pilgrim from 1987 to the present (7 total tests) indicates that 3 of the 7 tests conducted on MSSVs that have been installed for two operating cycles (i.e., 48 months) remained within the as-found TS tolerance of plus or minus 1%. The licensees as-found test data for the other 4 MSSVs that lifted outside the TS 1% tolerance showed that 3 of the valves exceeded the acceptance criteria in the negative or conservative direction. The one MSSV that exceeded the TS acceptance criteria in the positive direction was found by the licensee to be above the TS specified 1% tolerance by 8 psig. As shown in the fourth test of MSSV serial number BK 6302, the licensees test results for MSSVs stored in a controlled environment indicated that the impact of storage in a controlled environment on the opening setpoint was minimal.

The NRC staff finds that the licensee has demonstrated that the refurbishment in every two operating cycles, testing history of MSSVs from 1987 to the present, and storage conditions provide adequate assurance that the operational readiness of the valve to perform its safety function will not be impaired during the period that the proposed alternative is authorized.

Therefore, the NRC staff finds that the proposed alternative to extend the test interval for MSSV serial number BK 6302 installed in valve location RV-203-4A beyond the ASME OM Code 5-year test requirement is acceptable. Compliance with the ASME Code requirements would result in

hardship or unusual difficulty without a compensating increase in quality and safety due to unnecessary plant shutdown, unnecessary challenges to safety systems, and unnecessary cycling of equipment.

4.0 CONCLUSION

The NRC staff concludes that the proposed alternative to remove and test MSSV serial number BK 6302 installed in location RV-203-4A during RFO-17, along with the remaining other MSSV that will not have exceeded the 5-year test requirement by RFO-17, is authorized pursuant to 10 CFR 50.55a(a)(3)(ii) on the basis that compliance with the Code requirements would result in hardship or unusual difficulty without a compensating increase in quality and safety. The additional time beyond that required by the ASME Code should not impair the valves operational readiness. The proposed alternative is authorized until the completion of RFO-17.

Principal Contributor: William K. Poertner Date: May 27, 2008