ML13039A292
| ML13039A292 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 02/22/2013 |
| From: | George Wilson Plant Licensing Branch 1 |
| To: | Joseph Pacher Ginna |
| Thadani M NRR/DORl/LPL1-1 301-415-1476 | |
| References | |
| TAC ME8720 | |
| Download: ML13039A292 (7) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 22, 2013 Mr. Joseph E. Pacher Vice President RE. Ginna Nuclear Power Plant RE. Ginna Nuclear Power Plant, LLC 1503 Lake Road Ontario, NY 14519 SUB~IECT:
RE. GINNA NUCLEAR POWER PLANT - RE: RELIEF REQUEST 151-06, ASME CODE EXAMINATION REQUIREMENTS FOR REACTOR VESSEL BOTTOM MOUNTED INSTRUMENTATION NOZZLE A86 (TAC NO. ME8720)
Dear Mr. Pacher:
By letter dated April 24, 2012, Constellation Energy Nuclear Group LLC, the licensee for RE. Ginna Nuclear Power Plant (Ginna), submitted a request to the U.S. Nuclear Regulatory Commission (NRC, the Commission) for relief from certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI requirements at. Ginna.
Relief Request 151-06 for Ginna is applicable to the fifth 1 O-year inservice inspection (lSI) interval.
Relief Request 151-06 is proposed, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Paragraph 50.55a(a)(3)(ii). Approval of the relief request ISI-06 would provide the licensee an alternative to ASME Code,Section XI requirements to perform ultrasonic examination for each successive period of reactor pressure vessel bottom mounted instrumentation (BMI) penetration A86. This would allow the volumetric examinations on BMI Penetration Nozzle A86 to coincide with a planned removal of the Reactor Vessel Internals at the end of the fifth 10-year lSI interval.
The NRC staff has determined that the proposed alternative provides reasonable assurance of quality and safety when performing successive ultrasonic examinations, each period, on Reactor Pressure Vessel BMI Penetration Nozzle number AB6. Through its flaw evaluation, the licensee previously demonstrated that the continued service of BMI nozzle A86 was acceptable for a 40 year service life. The NRC staff evaluated the licensee's analysis, and agreed with the licensee's conclusions. The NRC staff's evaluation is contained in the letter from the NRC dated January 8,2013 to Mr. Joseph E. Pacher, Vice President, RE. Ginna Nuclear Power Plant (Agencywide Document Access and Management System Accession No. ML12355A429).
Accordingly, based upon the previous evaluation of structural integrity of the flaws, the review of the information provided in the licensee's submittals, and given the maximum time between volumetric re-inspection in accordance with the requirements of Item No. B4.40 of Table 1 of ASME Code Case N-729-1 for Ginna, the NRC staff concludes that the licensee's proposed alternative demonstrates that compliance with the specified requirements of 10 CFR 50.55a(g)(6)(ii)(D) would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(ii), the use of the proposed alternative to define an alternate examination zone below the J-groove weld is authorized for Ginna for the fifth 10-year lSI interval.
J. Pac her
- 2 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.
If you have any questions, please contact Mohan Thadani, the NRC Project Manager for Ginna, at (301) 415-1476 or email mohan.thadani@nrc.gov.
Sincerely,
~_--./I Georg;;;;;;:) Chief Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-244
Enclosure:
Relief Request ISI-06 cc w/encl: Distribution via Listserv
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST NO. ISI-06 R E. GINNA NUCLEAR POWER PLANT, LLC RE. GINNA NUCLEAR POWER PLANT DOCKET NOS. 50-244
1.0 INTRODUCTION
By letter dated April 24, 2012, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML121170481), Constellation Energy Nuclear Group LLC, the licensee for RE. Ginna Nuclear Power Plant (Ginna), submitted a request to the U.S. Nuclear Regulatory Commission (NRC, the Commission) for relief from certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI "Rules for Inservice Inspection of Nuclear Power Plant Components." requirements at Ginna.
Relief Request ISI-06 is proposed pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Paragraph 50.55a(a)(3)(ii). Approval of the relief request ISI-06 would provide the licensee an alternative to ASME Code,Section XI requirements to perform ultrasonic examination for each successive period of reactor pressure vessel bottom mounted instrumentation (BMI) penetration A86. This would allow the volumetric examinations on BMI Penetration Nozzle A86 to coincide with a planned removal of the Reactor Vessel Internals at the end of the fifth 1 O-year inservice inspection (lSI) interval.
Through its flaw evaluation, the licensee previously demonstrated that the continued service of BMI nozzle A86 was acceptable for a 40 year service life. The NRC staff evaluated the licensee's analysis, and agreed with the licensee's conclusions. The NRC staff's evaluation is contained in the letter from the NRC dated January 8, 2013 to Mr. Joseph E. Pacher, Vice President, R Ginna Nuclear Power Plant (ADAMS Accession No. ML12355A429). Based upon its testing and analysis the licensee requests relief ISI-06 from reexamination requirements normally associated with the identification of flaws. The licensee has proposed to define an alternate examination zone below the J-groove weld to satisfy the regulatory requirements to address the detection of flaws.
Enclosure
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2.0 REGULATORY EVALUATION
Paragraph to 10 CFR 50.55a(g) specifies that lSI of nuclear power plant components shall be performed in accordance with the requirements set forth in the ASME Code,Section XI, except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i), which states that the Commission may grant such relief and may impose such alternative requirement as it determines is authorized by law, and will not endanger life or property or the common defense and security and is otherwise in the public interest, given the consideration of the burden upon the licensee.
Paragraph 10 CFR 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. The regulation at 10 CFR 50.55a(g)(5)(iii) states that if the licensee has determined that conformance with certain code requirements is impractical for its facility, the licensee shall notify the Commission and submit, as specified in §50.4, information to support the determinations.
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 preserves examination requirements, set forth in the ASME Code,Section XI, to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that lSI of components and system pressure tests conducted during the first 1 O-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),
twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein.
When flaws are identified and accepted via ASME Code,Section XI, IWB-3132.3 or IWB-3142.4, the ASME Code directs the user that "[the component of interest is to] be reexamined during the next three inspection periods listed in the schedule of the inspection program of IWB-2400."
3.0 TECHNICAL EVALUATION
3.1 Licensee Evaluation Components for Which Relief is Requested Class 1, Reactor Pressure Vessel, Bottom Mounted Instrumentation (BMI) Penetration Nozzle A86.
ASME Code Requirements Paragraph IWB-2420(b) requirement regarding subsequent re-examinations.
- 3 Licensee's Request for Relief The licensee requested relief from performing all three required examinations due to complications caused by intervening components that are not regularly removed during refueling outages. Specifically, the licensee cites the fuel, core barrel, and associated lower internals as hindering access to the BMI nozzle for examination purposes.
Licensee's Proposed Alternative Examination The licensee proposes to perform a subsequent ultrasonic (UT) examination of BMI nozzle A86 during the 3rd period of the Fifth Interval lSI program. The licensee cites the very slow growth of Indication #1 as reported to the NRC in the flaw evaluation submitted previously as supporting this action. With the identified slow growth rate, the ASME Code required reexaminations would not serve to increase assurance of the structural adequacy of the nozzle, while presenting real difficulties such as increased dose and potential damage to intervening components.
Additionally, the licensee cites the every-outage visual examinations of the exterior of the BMI nozzles as providing further assurance regarding the state of the nozzle A86.
3.2
NRC Staff Evaluation
The ASME Code required re-examinations are most appropriate when applied to flaws and indications with appreciable growth rates, especially if the flaws are surface breaking. As discussed in the SE of the licensee flaw evaluation referenced in Section 1.0 of this safety evaluation, the NRC staff has previously accepted that the indications of interest are most likely fabrication flaws, slow growing, non-surface breaking, and of very little short-term concern. Due to the location and nature of the flaws, UT examination would impose hardship and unusual difficulty without a compensating increase in the level of quality or safety. Examination would optimally require the removal of the Upper Internals package, fuel, and the Core Barrel to provide full access to the BMI nozzles.
As discussed in the previous safety evaluation noted above, the license in its evaluation dispositioned one of the flaws as a laminar flaw, roughly 0.16 by 0.25 inches in diameter and 0.0 inches through-wall. The licensee determined that this flaw was acceptable for continued service in accordance with the ASME Code, and the staff concurred with the licensee's evaluation. The second flaw was analyzed for growth over a 40-year period beginning with the discovery of the flaw. The conclusion of this analYSis, which included a number of conservative assumptions, was that the flaw would grow from 0.167 inches depth to 0.188 inches depth, while the nozzle itself is 0.595 inch thick. The flaw was identified to be imbedded in the metal, and the flaw growth would not cause the flaw to become surface breaking. This licensee's evaluation supports the proposed relief and the NRC staff confirms that the proposed alternative provides reasonable assurance of structural integrity of the BMI nozzle A86.
The proposed alternative examination to take place during the 3rd period of the Fifth Interval lSI program would provide adequate assurance regarding the integrity of the nozzle A86 and the veracity of the licensee's flaw analysis. Therefore, the NRC staff concludes that neither flaw represents an analyzed threat to the structural integrity of the nozzle A86 for a 40-year period after the flaw discovery, and certainly until the 3rd period of the Fifth Interval lSI program, the staff concludes that the ASME Code required examinations would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
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4.0 CONCLUSION
The NRC staff concludes that the proposed alternative provides reasonable assurance of structural integrity of the BMI nozzle A86 and that complying with the ASME Code requirement listed above will result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Therefore, pursuant to 10 CFR SO.SSa(a)(3)(ii), the NRC staff authorizes the proposed alternative.
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 Contributors: D. Widrevitz Date: February 22, 2013
J. Pacher
- 2 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.
If you have any questions, please contact Mohan Thadani, the NRC Project Manager for Ginna, at (301) 415-1476 or email mohan.thadani@nrc.gov.
Sincerely,
/raJ George Wilson, Chief Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-244
Enclosure:
Relief Request ISI-06 cc w/encl: Distribution via Listserv DISTRIBUTION:
PUBLIC RidsNrrDorlLpl1-1 RidsNrrPMREGinna LPL1-1 Reading File RidsNrrLAKGoldstein RidsAcrsAcnw_MailCTR RidsNrrDorlDpr RidsRgn1 MailCenter D. Widrevitz RidsOgcRp ADAMS ACCESSION NO.. ML13039A292
- SE I nput OFFICE LPL 1-1/PM LPL1-1/LA DE/EVIB/BC LPL1-1/BC LPL 1-1/PM NAME MThadani KGoldstein SRosenberg*
GWilson MThadani DATE 02/21/13 02/22/13 01/24/2013 02/22/13 02/22/13 OFFICIAL RECORD COPY