ML092790210
| ML092790210 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 10/09/2009 |
| From: | Stang J Plant Licensing Branch II |
| To: | Heacock D Virginia Electric & Power Co (VEPCO) |
| Sreenivas V.NRR/DORL/LPL2-1 415-2597 | |
| References | |
| N1-I3-NDE-024, N2-I3-NDE-025, TAC ME1276, TAC ME1277 | |
| Download: ML092790210 (8) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 October 9, 2009 Mr. David A. Heacock President and Chief Nuclear Officer Virginia Electric and Power Company Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711
SUBJECT:
NORTH ANNA POWER STATION, UNIT NOS. 1 AND 2, THIRD 10-YEAR INTERVAL INSERVICE INSPECTION (lSI) PROGRAM, REACTOR COOLANT PRESSURE BOUNDARY VISUAL INSPECTIONS N1-13-NDE-024 AND N2-13-NDE-025 (TAC NOS. ME1276 AND ME1277)
Dear Mr. Heacock:
By letter dated May 12, 2009, Virginia Electric and Power Company (the licensee) requested relief from certain requirements of Section XI of the American Society of Mechanical Engineers, Boiler and Pressure Vessel Code (ASME Code), under the provisions of Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 50.55a(g)(6)(ii)(E), footnote 1 for the remainder of the third 1O-year Inservice Inspection (lSI) Interval for North Anna Power Station (NAPS), Unit Nos. 1 and 2.
The U.S. Nuclear Regulatory Commission (NRC) staff finds that the proposed alternative that the visual examinations performed on the bottom-mounted RPV instrument penetrations during the fall 2007 refueling outage for NAPS Unit NO.1 and fall 2008 refueling outage for NAPS Unit NO.2 provide an acceptable level of quality and safety. Therefore, the NRC staff authorizes the alternative in RR N1-13-NDE-024 and RR N2-13-NDE-025 pursuant to 10 CFR 50.55a(a)(3)(i) for the third 1O-year lSI interval.
All other requirements of ASME Code,Section XI for which relief has not been specifically requested remain applicable, including a third party review by the Authorized Nuclear lnservice Inspector.
D. Heacock
- 2 If you have any questions concerning this matter, please contact Dr. Sreenivas, at (301) 415-2597.
Sincere~
n Stang, Acting Branch Chief Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of l\\luclear Reactor Regulation Docket Nos. 50-338 and 50-339
Enclosure:
Safety Evaluation 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 THIRD 10-YEAR INTERVAL INSERVICE INSPECTION RELIEF NOS. N1-13-NDE-024 AND N2-13-NDE-025 NORTH ANNA POWER STATION, UNIT NOS. 1 AND 2 VIRGINA ELECTRIC AND POWER COIVIPANY DOCKET NOS. 50-338 AND 50-339
1.0 INTRODUCTION
By letter dated May 12, 2009, (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML091320639), as supplemented by letter dated August 24, 2009 (ADAMS Accession No. ML092370646), Virginia Electric and Power Company (the licensee), submitted Relief Requests (RRs) N1-13-NDE-024 and N2-13-NDE-025 for its third 10-year inservice inspection (lSI) interval at North Anna Power Station (NAPS) Units 1 and 2. The licensee has proposed that the visual examinations performed on the bottom-mounted reactor pressure vessel (RPV) instrument penetrations during the fall 2007 refueling outage for NAPS Unit 1 and fall 2008 refueling outage for NAP, Unit 2, provide an acceptable level of quality and safety as an alternative to performing the initial inspections in Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Section 50.55a(g)(6)(ii)(E), initial inspections in the next refueling outage after January 1, 2009.
The U.S. Nuclear Regulatory Commission (NRC) staff has evaluated the licensee's proposed alternative provides an acceptable level of quality and safety. pursuant to the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(i), and compliance with the 10 CFR 50.55a(g)(6)(ii)(E) requirements for the remainder of the third 1O-year lSI interval.
2.0 REGULATORY REQUIREMENTS According to 10 CFR 50.55a(g)(4), the American Society of Mechanical Engineers, Boiler and Pressure Vessel Code (ASIVIE 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 (lSI) 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 1O-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. The ASME Code of record for the NAPS Unit 1 third 10-year lSI interval program is the 1998 Edition Enclosure
- 2 with no Addenda of Section Xl of the ASME Code. The ASME Code of record for the NAPS Unit 2 third 1O-year lSI interval is the 1995 Edition with the 1996 Addenda.
Pursuant to 10 CFR 50.55a(a)(3) alternatives to requirements may be authorized by the NRC if the licensee demonstrates that: (i) the proposed alternatives 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 licensee submitted the subject request for authorization of an alternative, pursuant to 10 CFR 50.55a(a)(3)(i), which proposed to use previous bare metal visual examinations of the bottom-mounted RPV instrument penetrations to examination requirements of 10 CFR 50.55a(g)(6)(ii)(E).
3.0 EVALUATION Relief Request (RR) Nos. N1-13-NDE-024 (NAPS Unit 1) and N2-13-NDE-025 (NAPS Unit 2)
ASME Code Components ASME Code Class:
1 System RPV Examination Category:
B-P Item No.:
ASME Code,Section XI, Item B15.80 lSI Component 10:
RPV Bottom-Mounted Instrument (BMI) Penetrations ASME Code and 10 CFR 50.55a Requirements ASME Code Case N-722, "Additional Examinations for PWR Pressure Retaining Welds in Class 1 Components Fabricated with Alloy 600/82/182 Materials,Section XI, Division 1," establishes augmented lSI requirement in 10 CFR 50.55a(g)(6)(ii)(E). ASME Code Case N-722 requires, in part, that the bare metal visual inspection of BMI nozzles are performed every other refueling outage. Footnote 1 to 10 CFR 50.55a(g)(6)(ii)(E) requires that the initial BMI inspections be performed at the next refueling outage after January 1, 2009.
Section 50.55a(g)(6)(ii)(E) requires that "All licensees of pressurized water reactors shall augment their lSI program by implementing ASME Code Case N-722 subject to the conditions specified in 10 CFR 50.55a(g)(6)(ii)(E)(2) through (4) of this section. The inspection requirements of ASME Code Case N-722 do not apply to components with pressure retaining welds fabricated with Alloy 600/82/182 materials that have been mitigated by weld overlay or stress improvement."
Licensee's Basis for Relief Request The licensee stated that NAPS, Units 1 and Unit 2, completed bare metal visual examination of RPV BMI penetrations prior to the "initial inspection" indicated by 10 CFR 50.55a(g)(6)(ii)(E),
which became effective October 10, 2008. NAPS, Unit 1 inspections were performed during the fall 2007 refueling outage, and NAPS, Unit 2, inspections were performed during the fall 2008 refueling outage. These bare metal visual inspections met the intent of ASME Code Case N-722.
- 3 ASME Code Case N-722 establishes additional requirements to the examination requirements of ASME Code,Section XI, Table IWB-2500-1 for pressurized water reactor plants having partial or full penetration welds in ASME Code, Class 1 components fabricated with Alloy 600/82/182 material.
For RPV ASME Code,Section XI, Table IWB-2500-1, Item Number B15.80, RPV BMI penetrations, all penetrations require Visual Examination (VE) to the requirements of ASME Code,Section XI, IWB-3522, every other refueling outage.
In Table 1 Examination Categories Continued under Footnotes. The ASME Code Case N-722 includes specific requirements for the VE and the qualification of personnel performing the VE.
The following paragraphs of footnotes are applicable:
Footnote (3): The VE performed on Alloy 600/82/182 components for evidence of pressure boundary leakage and corrosion on adjacent ferritic steel components shall consist of the following:
(a)
A direct VE of the bare-metal surface performed with the insulation removed. Alternatively, the VE may be performed with insulation in place using remote visual inspection equipment that provides resolution of the component metal surface equivalent to a baremetal direct VE.
(b)
The VE may be performed when the system or component is depressurized.
(c)
The direct VE shall be performed at a distance not greater than 4 ft (1.2 m) from the component and with a demonstrated illumination level sufficient to allow resolution of lower case characters having a height of not greater than 0.105 in (2.7 mm).
Footnote (4): Personnel performing the VE shall be qualified as VT-2 visual examiners and shall have completed a minimum of four (4) hours of additional training in detection of borated water leakage from Alloy 600/82/182 components and the resulting boric acid corrosion of adjacent ferritic steel components The bottom-mounted RPV instrument penetrations examinations during the fall 2007 and fall 2008 refueling outages were performed to the enhanced [VE] requirements and the personnel training and qualification requirements as described in Enclosure 1, "Examiner Qualification and Resolutions Requirements. This enclosure documents a comparison of the bare metal visual examinations performed on the RPV BMI nozzles at NAPS Units 1 & 2 performed during previous outages (N1R19 and N2R19) with the new requirements of ASME Code Case N-722. The two areas related to examination equivalency were addressed:
Personnel Qualifications: The licensee has stated that "the examiners that performed these examinations held current VT-2 (non-alternative) and VT-3 qualifications. In addition, each of the examiners had successfully taken the Dominion Boric Acid Corrosion Control (BACC) Inspector training. The inspection team included at least one VT examiner that has also completed the Dominion BACC Evaluator training and qualification requirements". The licensee has also stated that "the examiners that performed these
-4 bare metal visual examinations met the requirements of ASME Code Case N-722 as VT-2 qualified examiners with an additional four hours of training addressing the detection of borated water leakage from Alloy 600/82/182 components and the resulting boric acid corrosion of adjacent ferritic steel components. Based upon the additional training of the visual examiners the qualifications of the bare metal VEs of the BMI nozzle penetrations performed during the N1 R19 and N2R19 outages are considered equivalent to the personnel qualification requirements of ASME Code Case N-722".
Resolution Requirements: Further, the licensee presented that "the previous bare metal VEs were performed using a (VT-2) examination technique and required each penetration to be examined for evidence of leakage for 360 degrees around each nozzle. The bare metal VEs were documented in the applicable Engineering Periodic Test Procedure.
These periodic test procedures specify the use of inspection equipment to be used for the inspection, which consists of a mirror, portable lights, and a visual testing examination resolution card. Access to the BMI nozzles for the bare metal VE is through removable insulation panels. The bare metal visual examinations of the BMI nozzles were performed in accordance with the direct VE requirements of within 4 feet and sufficient illumination to resolve 0.105 inches lower case characters. Based upon the access for the examiner to perform the bare metal VE of the BMI nozzle penetrations, [and] the equipment used to perform the examination (mirror, flashlight, 0.105 inches low case character resolution card), the [resolution of the] previously performed bare metal VEs of the BMI nozzle penetration are considered equivalent to the resolution requirements of ASME Code Case N-722".
Staff Evaluation Section 50.55a(g)(6)(ii)(E) requires that "Alllicensees of pressurized water reactors shall augment their lSI program by implementing ASME Code Case N-722 subject to the conditions specified in 10 CFR 50.55a(g)(6)(ii)(E)(2) through (4) of this section. The licensee has requested that the VEs performed during the fall 2007 refueling outage for NAPS, Unit 1 and fall 2008 refueling outage for NAPS Unit 2 be credited as the initial inspections requirements required in 10 CFR 50.55a(g)(6)(ii)(E). The licensee has proposed as an alternative to the requirements in 10 CFR 50.55a(g)(6)(ii)(E) that inspections performed in the fall of 2007 for NAPS Unit 1 and the fall of 2008 for NAPS Unit 2 be considered the initial inspections to meet the 10 CFR 50.55a(g)(6)(ii)(E) footnote requirements for the performance of the initial inspection.
The licensee made a comparison of its inspection procedure and inspector qualification requirements used for the examinations of the RPV instrument penetrations during the fall 2007 refueling outage for NAPS Unit 1 and fall 2008 refueling outage for NAPS Unit 2, respectively, to those outlined in ASME Code Case N-722. The licensee noted in its request for additional information response dated August 12, 2009, that it had inspected BMI penetrations twice in NAPS Units 1 and 2 finding no indications of leakage, or signs of corrosion or boric acid residue on either unit. The licensee also noted that it examined all BMI penetrations for both NAPS, Units 1 and 2 during the fall 2007 and fall 2008 refueling outages, respectively and this approach was consistent with the requirements of Table 1 of ASME Code Case N-722. The staff reviewed the licensee's comparison of the inspection procedure and inspector qualification requirements to the ASME Code Case N-722 footnote requirements and determined that the licensee's inspection procedure and inspector qualification is equivalent to each requirement in ASME Code Case N-722. Therefore, the NRC staff determined that the licensee's proposed alternative to credit the
- 5 visual examinations performed during the fall 2007 refueling outage for NAPS Unit 1 and fall 2008 refueling outage for NAPS Unit 2 to meet the ASME Code Case N-722 footnotes and 10 CFR 50.55a(g)(6)(ii)(E) requirements is acceptable and provides an acceptable level of quality and safety.
4.0 CONCLUSION
As set forth above, the NRC staff determined that the licensee's proposed alternative provides an acceptable level of quality and safety. Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(i), and is in compliance with the 10 CFR 50.55a(g)(6)(ii)(E) requirements. Therefore, the NRC staff authorizes the licensee's proposed alternative at NAPS Units 1 and 2 for the remainder of the third 10-year lSI interval. All other ASME Code,Section XI, requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: Thomas K. McLellan, NRR Date of Issuance: October 9, 2009
D. Heacock
- 2 If you have any questions concerning this matter, please contact Dr. Sreenivas, at (301) 415-2597.
Sincerely, IRA!
John Stang, Acting Branch Chief Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-338 and 50-339
Enclosure:
Safety Evaluation cc w/encl: Distribution via Listserv DISTRIBUTION: Public RidsAcrsAcnw MailCTR Resource LPL2-1 R/F RidsRgn2MailCenter Resource (GMcCoy)
RidsNrrDorlLpl2-1 Resource RidsOgcRp Resource RidsNrrLAMO'Brien Resource Ridsl\\lrrDciCsgb Resource RidsNrrPMNorthAnna Resource PPatnaik, NRR TMcLellan, NRR MMitchell, NRR a e ADAMS Accesslon N0.: ML092790210
- bly memo d t d OFFICE NRR/LPL2-1 /PM NRR/LPD2-1/LA NRR/CSGBI/BC NRR/LPL2-1/BC NAME VSreenivas MO'Brien (SRohrer for)
MMitchell*
JStang DATE 10/06/09 10/8/09 09/16/09 10/9/09 OFFICIAL RECORD COPY