ML050870348
| ML050870348 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 05/17/2005 |
| From: | Gramm R NRC/NRR/DLPM/LPD4 |
| To: | Parrish J Energy Northwest |
| Benney B, NRR/DLPM, 415-3764 | |
| References | |
| TAC MC5189, TAC MC5190 | |
| Download: ML050870348 (10) | |
Text
May 17, 2005 Mr. J. V. Parrish Chief Executive Officer Energy Northwest P.O. Box 968 (Mail Drop 1023)
Richland, WA 99352-0968
SUBJECT:
COLUMBIA GENERATING STATION - AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) INSERVICE INSPECTION PROGRAM RELIEF REQUESTS 2ISI-29 AND 2ISI-30, SUBSEQUENT ASME SECTION XI EDITION AND ADDENDA FOR PRESSURE TESTING (TAC NOS. MC5189, MC5190)
Dear Mr. Parrish:
By two separate letters to the Nuclear Regulatory Commission (NRC) dated November 22, 2004 (Agencywide Document Access System (ADAMS) Accession Nos. ML043350363, and ML043350364), as supplemented by letter dated April 28, 2005 (ADAMS Accession No. ML051260210), Energy Northwest, the licensee for the Columbia Generating Station (CGS),
submitted inservice inspection (ISI) relief requests 2ISI-29 and 2ISI-30 for its current 10-year ISI interval. By letter dated December 6, 2004 (ADAMS Accession No. ML043550218), the licensee provided the drawings referring to the scope of relief request 2ISI-29 that were inadvertently left out of the letter dated November 22, 2004, for 2ISI-29. The applications proposed relief from the test condition holding time for a small segment of the standby liquid control system (SLC) under relief request 2ISI-29, and use of a portion of a subsequent Edition of the ASME Section XI Code and Addenda for pressure testing Code Category B-P items under relief request 2ISI-30.
The NRC staff completed its review and concluded that compliance with the ASME Code pressure test hold time requirement for the SLC piping section discussed in relief request 2ISI-29 causes undue hardship due to high SLC relief valve failure rates. Pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(a)(3)(ii), the NRC staff authorizes the licensees alternative relief to perform a VT-2 inspection while performing the 3 - 5 minute quarterly operational test as requested under relief request 2ISI-29 for CGS, for its current 10-year ISI interval. This completes the NRC staff review for TAC No. MC5189.
The NRC staff completed its review of relief request 2ISI-30 which proposed using ASME Code Section XI, 2001 Edition, 2003 Addenda, Table IWB-2500-1, for examination category B-P components. The NRC staff concluded that all related requirements are met, and therefore, pursuant to 10 CFR 50.55a(g)(4)(iv), the staff approves the use of relief request 2ISI-30 for CGS for the remainder of its current 10-year interval.
J. Parrish The NRC staff's Safety Evaluation for Relief Request Numbers 2ISI-29 and 2ISI-30 for CGS are enclosed. If you need further clarification, please contact Brian Benney at (301) 415-3764.
Sincerely,
/RA/
Robert A. Gramm, Chief, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-397
Enclosure:
As stated cc w/encl: See next page
J. Parrish The NRC staff's Safety Evaluation for Relief Request Numbers 2ISI-29 and 2ISI-30 for CGS are enclosed. If you need further clarification, please contact Brian Benney at (301) 415-3764.
Sincerely,
/RA/
Robert A. Gramm, Chief, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-397
Enclosure:
As stated cc w/encl: See next page DISTRIBUTION:
PUBLIC RidsNrrDlpmiv2 (RGramm)
RidsAcrsAcnwMailCenter PDIV-2 R/F RidsNrrPMBBenney JDixon-Herrity RidsNrrDlpmiv (HBerkow)
RidsNrrLALFeizollahi OgcRp RidsRgn4MailCenter TChan ADAMS ACCESSION NO. ML050870348
DReddick RGramm DATE 5/6/05 4/14/05 2/23/05 5/13/05 5/17/05 OFFICIAL RECORD COPY
Columbia Generating Station cc:
Mr. W. Scott Oxenford (Mail Drop PE04)
Vice President, Technical Services Energy Northwest P. O. Box 968 Richland, WA 99352-0968 Mr. Albert E. Mouncer (Mail Drop PE01)
Vice President, Corporate Services/
General Counsel/CFO Energy Northwest P.O. Box 968 Richland, WA 99352-0968 Chairman Energy Facility Site Evaluation Council P.O. Box 43172 Olympia, WA 98504-3172 Mr. Douglas W. Coleman (Mail Drop PE20)
Manager, Regulatory Programs Energy Northwest P.O. Box 968 Richland, WA 99352-0968 Mr. Gregory V. Cullen (Mail Drop PE20)
Supervisor, Licensing Energy Northwest P.O. Box 968 Richland, WA 99352-0968 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Chairman Benton County Board of Commissioners P.O. Box 190 Prosser, WA 99350-0190 Senior Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 69 Richland, WA 99352-0069 Mr. Dale K. Atkinson (Mail Drop PE08)
Vice President, Nuclear Generation Energy Northwest P.O. Box 968 Richland, WA 99352-0968 Mr. William A. Horin, Esq.
Winston & Strawn 1400 L Street, N.W.
Washington, DC 20005-3502 Mr. Matt Steuerwalt Executive Policy Division Office of the Governor P.O. Box 43113 Olympia, WA 98504-3113 Ms. Lynn Albin Washington State Department of Health P.O. Box 7827 Olympia, WA 98504-7827 Technical Services Branch Chief FEMA Region X 130 228th Street S.W.
Bothell, WA 98201-9796
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO RELIEF REQUEST NUMBERS 2ISI-29 AND 2ISI-30 ENERGY NORTHWEST COLUMBIA GENERATING STATION DOCKET NO. 50-397
1.0 INTRODUCTION
By two separate letters to the Nuclear Regulatory Commission (NRC or Commission) dated November 22, 2004 (Agencywide Document Access System (ADAMS) Accession Nos.
ML043350363, and ML043350364), as supplemented by letter dated April 28, 2005 (ADAMS Accession No. ML051260210), Energy Northwest (EN), the licensee for the Columbia Generating Station (CGS), submitted Relief Request Numbers 2ISI-29 and 2ISI-30, requesting relief from American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI requirements related to the ASME Section XI, IWA-5213 pressure test holding time, and use of a portion of a subsequent year and Addenda of the ASME Code Section XI at the Columbia Generating Station (CGS). By letter dated December 6, 2004 (ADAMS Accession No. ML043550218), the licensee provided the drawings referring to the scope of relief request 2ISI-29 that were inadvertently left out of the letter dated November 22, 2004, for 2ISI-29.
Relief Request 2ISI-29 would authorize the use of a proposed alternative to visually examine (VT-2) a portion of the standby liquid control system (SLC) during its 3 - 5 minute quarterly functional test at 1240 psig rather than maintain a 10 minute hold time. Relief Request 2ISI-30 would authorize the use of ASME Section XI, 2001 Edition, 2003 Addenda, Table IWB-2500-1 for examination category B-P components. Both relief requests would be for the remaining portion of the second 10-year inservice inspection (ISI) interval at the CGS.
2.0 REGULATORY EVALUATION
Alternatives to NRC requirements may be authorized or relief may be granted by the NRC pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(a)(3)(i), 10 CFR 50.55a(a)(3)(ii), or 10 CFR 50.55a(g)(6)(i). In proposing alternatives, the licensee must demonstrate that: (1) the proposed alternatives provide an acceptable level of 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. Pursuant to 10 CFR 50.55a(g)(4)(iv), ISI items may meet the requirements set forth in subsequent Editions and Addenda of the ASME Code that are incorporated by reference in 10 CFR 50.55a(b), subject to the limitations and modifications listed therein, and subject to Commission approval. Portions of Editions and Addenda may be used provided that related requirements of the respective Editions and Addenda are met.
The licensee submitted Relief Request 2ISI-29, pursuant to 10 CFR 50.55a(g)(5)(iii), as a proposed alternative to the implementation of ASME Code,Section XI holding times required by IWA-5213 for a Class 2 portion of the SLC piping for the remaining portion of the second ISI interval for the CGS.
3.0 TECHNICAL EVALUATION
- RELIEF REQUEST 2ISI-29 3.1 Code Requirements for Which Relief is Requested The licensee requested relief from the requirements of ASME Section XI, Code Case N-498-4, which has been approved for use in Regulatory Guide 1.147, Revision 13, with the provision that IWA-5213, "Test Condition Holding Times," of ASME Section XI 1989 Edition be used.
The ISI Code of Record for CGS is the 1989 Edition of ASME Section XI.
3.1.1 System/Component(s) for Which Relief is Requested The requested relief from the holding time requirements applies to Examination Category C-H, Item Numbers C7.40, C7.60, and C7.80, which apply to piping, pumps and valves for the SLC system. The affected portion of the ASME Section III Class II SLC system is from the SLC pumps 1A and 1B to valves SLC-V-3A/3B, and to relief valves SLC-RV-29A/B. In accordance with the NRC-approved conditions for use with this Code Case, the pressure test requires a hold time of 10 minutes in accordance with IWA-5213, prior to performing the VT-2 examination.
3.2 Licensee's Proposed Alternative and Bases The licensee stated that the ASME Code requirement for a 10-minute hold time prior to performing the VT-2 visual examination is impractical in this case because the hold time increases the potential of damage to relief valves SLC-RV-29A and SLC-RV-29B. The section of the SLC system subject to this pressure test contains a small volume of fluid, which is circulated through 1-inch, 1-1/2-inch, 3-inch, and 4-inch nominal pipe size (NPS) pipe and a small test tank (210 gallon capacity). The pump suction pressure is approximately 50 psig and the pump discharge pressure is approximately 1240 psig. The system test fluid (demineralized water) rapidly heats up, causing chattering of the system relief valves and erratic pump discharge. The licensee stated that relief valves SLC-RV-29A and SLC-RV-29B have experienced frequent set point failures. Investigation into the frequent failures of relief valves SLC-RV-29A and SLC-RV-29B to meet their set points concluded that excess operation of the SLC system during the quarterly functional test leads to relief valve chatter, which damages the sealing surfaces. Damaged sealing surfaces prevent the relief valves from meeting their set point requirement. Procedure enhancements made after this investigation have significantly reduced the valves' failure rate. These enhancements include limiting the time of operation during the system functional test. To reduce the likelihood of damage to the relief valves, the system is now normally operated for 3 - 5 minutes during the functional test. If the functional test cannot be completed in this time frame, the system is allowed to cool and restarted to continue the test. Prior to the procedure enhancements, SLC-RV-29A failed 2 of its 5 tests in a five-year period (1990-1995). During the same five-year period, SLC-RV-29B failed 4 of its 5 tests. Since making the procedure changes in 1996, there have been two failures of SLC-RV-29A and one failure of SLC-RV-29B. The three failures occurred with the valves that were installed during the functional tests when the ASME Section Xl first and second inspection period VT-2 examinations were performed. For these examinations, the system was in operation for greater than 10 minutes due to the 10-minute hold time requirement. Running the system during the functional test for the length of time to meet the 10-minute hold time increases the potential to damage the relief valve sealing surface resulting in set point failure.
The licensee stated that it is not possible to pressurize this portion of the system with the hydro pump without disconnecting the pumps from the system and installing blind flanges with fittings to connect the hydro pump. This would involve major maintenance on the system and is not considered prudent to perform for this visual examination.
The alternative that the licensee proposes is to perform a VT-2 examination of this uninsulated section of piping during its quarterly 3 - 5 minute operating time without implementing a hold time. The system pressure rapidly increases to the 1240 psig operating pressure when the pump starts and the system pressure should reveal any through wall discontinuities without implementing the 10-minute hold time required by IWA-5213. The duration of the alternative would be for the second 10-year inservice inspection interval, which ends on December 12, 2005.
3.3 Staff Evaluation The licensee submitted Relief Request 2ISI-29 and, pursuant to 10 CFR 50.55a(g)(5)(iii),
indicated that compliance with the ASME Section XI 10-minute hold time was impractical for CGS. The basis for the impracticality was damage to the SLC relief valves caused by chattering of relief valves SLC-RV-29A/B during the hydrostatic test. The chattering is caused by the heating of the small volume of liquid involved in this section of piping from the hydrostatic pump with a suction pressure of 50 psig and a discharge pressure of 1240 psig. The end result is high failure rates at the set points of the subject relief valves. Based on the information provided by the licensee, the staff concludes that the licensee has sufficiently demonstrated hardship when complying with the ASME Code requirement. As an alternative, the licensee proposed performance of a VT-2 inspection of the affected section of piping during its quarterly operational test at 1240 psig.
The duration of the VT-2 examination would be 3 - 5 minutes and would cover the entire length of the uninsulated piping. The staff notes that this would equate to 12 - 20 minutes per year that the affected piping would be at operating pressure while being examined by VT-2 personnel. Table IWC-2500-1 of the 1989 Edition of ASME Section XI, requires that the affected Code Categories have a system pressure test once each inspection period with a hold time of 10 minutes. The licensee's alternative would exceed the time at operating pressure by 32 - 60 minutes per period over the 10 minute holding time required per ASME Section XI. The 3 - 5 minute time segments at operating pressure, however, are not equivalent to the 10 minute hold time, which is considered the minimum time for a tight crack to expose leakage on uninsulated piping through a VT-2 inspection. In this case, the staff considers maintaining the operability of the SLC relief valves, and the cumulative minutes at operating pressure over the period, overriding factors to meet the 10 minute hold time for this short section of piping. The staff concludes that the licensee's alternative provides reasonable assurance of structural integrity.
4.0 CONCLUSION
The NRC staff concludes that for relief request 2ISI-29, imposition of the ASME Code requirements on the licensee would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety, and that the licensee's proposed alternative provides reasonable assurance of structural integrity of the SLC system. Therefore the licensees proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(ii) for the CGS for the remainder of the second 10-year ISI interval.
All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
5.0 TECHNICAL EVALUATION
- RELIEF REQUEST 2ISI-30 5.1 Code Requirements for Which Relief is Requested CGS uses ASME Section XI, 1989 Edition with no Addenda.
5.1.1 System/Component(s) for Which Relief is Requested All ASME Class 1 pressure retaining components.
5.2 Licensee's Proposed Alternative and Bases The licensee proposes to use ASME Section XI, 2001 Edition, 2003 Addenda, Table IWB-2500-1, Examination Category B-P and all related requirements, incorporated by reference in 10 CFR 50.55a(b), by the Federal Register Notice dated October 1, 2004 (69 FR 58804).
The licensee requests the use of the later edition of the ASME Code pursuant to 10 CFR 50.55a(g)(4)(iv) and states that all related requirements including limitations identified in 10 CFR 50.55a are to be met.
5.3 Staff Evaluation Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the pre-service examination requirements, set forth in the ASME Code,Section XI, "Rules for Inservice Inspection (ISI) of Nuclear Power Plant Components," to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein.
Pursuant to 10 CFR 50.55a(g)(4)(iv), inservice examination of components and system pressure tests 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 therein, and subject to Commission approval. Portions of editions or addenda may be used, provided that all related requirements of the respective editions and addenda are met.
The ASME Code,Section XI, 2001 Edition with Addenda through 2003, was incorporated by reference into 10 CFR 50.55a(b) on November 1, 2004. The NRC staff's position regarding the use of the above Code has been published in the Federal Register on October 1, 2004 (69 FR 58804), subject to certain limitations and modifications. By letter dated November 22, 2004, EN submitted relief request 2ISI-30, which requested NRC approval, under the terms of 10 CFR 50.55a(g)(4), to apply the ASME Code,Section XI, 2001 Edition with Addenda through 2003, to the second ISI interval for CGS.
When using portions of later editions and addenda of the Code, all related requirements including limitations identified in 10 CFR 50.55a are to be met. Under 10 CFR 50.55a(b)(2),
three limitations are identified for pressure testing:
1.
(xx) - This paragraph defines hold times for Code Class 2 and 3 system leakage tests. This is not applicable since this request applies to Code Class 1 pressure retaining components.
2.
(xxvi) - This paragraph defines pressure testing of mechanical joints during repair and replacement activities. Because this request does not include repair and replacement activities, this limitation is not applicable.
3.
(xxvii) - This paragraph addresses insulation removal when pressure-testing Code Class I borated systems. Since CGS is a boiling water reactor and does not have Code Class I borated systems, this limitation is not applicable to this request.
In addition, the licensee stated that the following related requirements from ASME Section XI, 2001 Edition, 2003 Addenda would be implemented as applicable to Examination Category B-P:
1.
IWB-5220 System Leakage Test 2.
Examination Method - VT-2 a) IWA-2212 VT-2 Examination b) IWA-2300 Qualifications of Nondestructive Examination Personnel c) IWA-5000 System Pressure Tests 3.
Acceptance Standard a) IWB-3522 Standards for Examination Category B-P b) IWB-3142 Acceptance c) IWA-5250 Corrective Action d) IWA-5243 Components with Leakage Collection Systems e) IWA-5242 Insulated Components f) IWA-5244 Buried Components The staff concludes that the licensee has committed to complying with the related requirements and limitations pertaining to implementation of the pressure testing of Class 1 pressure retaining components under ASME Section XI, 2001 Edition, 2003 Addenda as applicable to Examination Category B-P, and the request for relief under 2ISI-30 for CGS is acceptable.
6.0 CONCLUSION
Based on the above review, the NRC staff concludes that the use of ASME Section XI, 2001 Edition, 2003 Addenda, Table IWB-2500-1, for Examination Category B-P components, is acceptable. Therefore, pursuant to 10 CFR 50.55a(g)(4)(iv), the staff approves for use the portion of later Edition of the ASME Code as submitted under relief request 2ISI-30 for the remainder of the second ISI interval at CGS.
All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: T. K. Steingass Date: May 17, 2005