NL-09-0406, Second 10-Year Interval Inservice Inspection Program. Submittal of Revised Relief Requests
| ML090830276 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 03/23/2009 |
| From: | Ajluni M Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-09-0406 | |
| Download: ML090830276 (18) | |
Text
Southern Nuclear Operating Company, Inc SOUTHERN COMPANY A
March 23, 2009 Ellerg)' to Serlle Your World Docket Nos.: 50-424 NL-09-0406 50-425 U. S. Nuclear Regulatory Commission ATrN: Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant Second 10-Year Intervallnservice Inspection Program Submittal of Revised Relief Requests Ladies and Gentlemen:
Pursuant to 10 CFR 50.55a(g)(5)(iv), Southern Nuclear Operating Company hereby submits the enclosed revised relief requests for the Vogtle Electric Generating Plant - Units 1 and 2, Second 10-Year Intervallnservice Inspection Program. The original Relief Requests submitted May 30, 2008 have been revised based on NRC comments during a teleconference on December 17, 2008. These relief requests are coverage relief requests where it is impractical to obtain more than 90 percent coverage and there is reasonable assurance of structural integrity. Two of the nine relief requests pertain to pipe weld examinations performed after the implementation of risk informed inservice inspection (RI-ISI). The relief requests are requested to be approved by May 29, 2009.
This letter contains no NRC commitments. If you have any questions, please advise.
Sincerely, iVW9~
M. J. Ajluni Manager, Nuclear Licensing MJAITAH/daj
U. S. Nuclear Regulatory Commission NL-09-0406 Page 2
Enclosures:
- 1. RR-49, Vogtle - Units 1 and 2 Reactor Pressure Vessel Shell and Bottom Head Welds
- 2. RR-50, Vogtle - Units 1 and 2 Class 2 Vessel Weld Examinations
- 3. RR-51 , Vogtle - Units 1 and 2 Class 2 Residual Heat Removal Heat Exchanger Shell Welds cc: Southern Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. T. E. Tynan, Vice President - Vogtle Mr. D. H. Jones, Vice President - Engineering RType: CVC7000 U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. R. E. Martin, NRR Project Manager - Vogtle Mr. M. Cain, Senior Resident Inspector - Vogtle
Vogtle Electric Generating Plant - Units 1 and 2 Second 10-Year Intervallnservice Inspection Program Submittal of Relief Requests Enclosure 1 Relief Request RR-49 Reactor Pressure Vessel Shell and Bottom Head Welds
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR SO.SSa(g)(S)(iii)
RR-49 Version 2.0 Plant Site-Unit: Vogtle Electric Generating Plant - Units 1 and 2.
Interval-Interval 2nd lSI Interval - May 31, 1997 through May 30,2007.
Dates:
Requested Date 10 CFR 50.55a(g)(5)(iv) states: Where an examination requirement by for Approval and the code or addenda is determined to be impractical by the licensee and Basis is not included in the revised inservice inspection program as permitted by paragraph (g)(4) of this section, the basis for this determination must be demonstrated to the satisfaction of the Commission not later than 12 months after the expiration of the initial 120-month period of operation from start of facility commercial operation and each subsequent 120 month period of operation during which the examination is determined to be impractical." Hence, SNC is asking for approval as soon as possible in order to close-out the second lSI interval activities.
ASME Code Class 1, ASME Section XI Category B-A, Items B1.11, B1.12, and B1.21 Components Affected: reactor pressure vessel (RPV) welds, as shown in Table RR-49.
Applicable Code Edition and ASME Section XI, 1989 Edition with no addenda.
Addenda:
Applicable Code ASME Item numbers (B1.11, B1.12, and B1.21) listed above for Table Requirements: IWB-2500-1, Examination Category B-A, require that 100% of the length of each weld be examined. Per Code Case N-460, coverage greater than 90% of the required examination volume is acceptable. The examination volume is shown in ASME Section XI, Figure IWB-2500-1 for Item Number B1.11, Figure IWB-2500-2 for Item Number B1.12, and Figure IWB-2500-3 for Item Number B1.21.
Impracticality of Physical limitations due to the geometric configuration of the welded Compliance: areas restricted coverage of the examination volume as required by the figures. A total of seven RPV welds for Vogtle-1 and -2 are shown in Table RR-49. Three longitudinal welds on the Vogtle-1 RPV are included but the corresponding welds for Vogtle-2 did not have the limited examination. The design of the Vogtle-2 RPV included placing the core support lugs at different azimuths from the three lower shell longitudinal welds. As noted in the limitations, additional positioning of the ultrasonic transducer was undertaken to maximize the coverage for these seven welds so that the welds were examined to the fullest extent practical.
Appreciably increasing coverage was impractical due to the interferences described in Table RR-49.
El-l
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR 50.55a(g)(5)(iii)
RR-49 Version 2.0 Burden Caused To obtain more coverage, the design of the Unit-1 RPV would need to be by Compliance: changed to:
- 1. Re-Iocate the six core support lugs away from the three longitudinal shell welds (welds W18 through W20) and circumferential shell weld W06, plus
- 2. Re-Iocate the RPV bottom-mounted inspection (BMI) tubes away from bottom head circumferential weld W07.
To obtain more coverage, the design of the Unit-2 RPV would need to be changed to:
- 1. Re-Iocate the six core support lugs away from circumferential shell weld W06, plus
- 2. Re-Iocate the RPV bottom-mounted inspection (BMI) tubes away from bottom head circumferential weld W07.
To change the design of the Vogtle reactor pressure vessels to obtain more examination coverage would be a significant burden on SNC.
Proposed The examination of these seven welds was performed using automated Alternative and ultrasonic techniques qualified throUgh the ASME Section XI, Appendix Basis for Use: VIII process. A large percentage of the weld root was interrogated for these seven welds and no ultrasonic indications exceeded the allowable flaw tables. In addition, VT-2 visual examinations are performed each refueling outage for these components. The visual examinations have not found any through-wall flaws on the RPV shell or head welds. Based on these examination results, plus the cumulative volumetric examination coverage of all RPV shell welds, there is reasonable assurance of structural integrity. There is no anticipated impact upon the overall plant quality and safety, and the granting of relief should not jeopardize the health and safety of the public. Therefore, pursuant to the requirements of 10 CFR 50.55a (g)(5)(iii), relief is requested from performing the 100%
volumetric examination requirements of the applicable Category B-A welds listed in Table RR-49.
Duration of Proposed The proposed relief request is applicable for the 2 nd Interval.
Relief Request:
Precedents: These RPV welds were examined during the first lSI interval with less coverage and were documented to the NRC. The NRC granted approval for these limited examinations by letters dated January 29, 1999 for Unit 1 and June 5, 2000 for Unit-2.
References:
TAC Nos. MA0284 and MA3944 plus MA4356 Status: Awaiting NRC approval.
El-2
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR SO.SSa(g)(S)(iii)
RR-49 Version 2.0 TABLE RR-49 Weld Number I ASME Examined Item Coverage Basis for Limited Coveraae 11201-V6-001-W06 81.11 78.4% The UT examination of this circumferential weld was limited by the proximity of six RPV core support lugs. Scanning was conducted between and below the obstructing lugs with the 1R13 (Fa1l2006 scan boundaries maximized by visually-assisted positioning of the remote examination head Outaae) so that the scan starts and stops were as close to the core support luas as possible.
11201-V6-001-W18 81.12 79.0% The UT examination of this longitudinal weld was limited by the proximity of RPV core support lug at the 60 0 azimuth location. Scanning was conducted in both the perpendicular 1R13 (Fall 2006 and parallel directions around the obstructing lug with the scan boundaries maximized by Outage) visually-assisted positioning of the remote examination head so that the scan starts and stops were as close to the core support IUQ as possible.
11201-V6-001-W19 81.12 79.0% The UT examination of this longitudinal weld was limited by the proximity of RPV core support lug at the 1800 azimuth location. Scanning was conducted in both the perpendicular 1R13 (Fall 2006 and parallel directions around the obstructing lug with the scan boundaries maximized by Outage) visually-assisted positioning of the remote examination head so that the scan starts and stops were as close to the core support luq as possible.
11201-V6-001-W20 81.12 79.0% The UT examination of this longitudinal weld was limited by the proximity of RPV core support lug at the 300 0 azimuth location. Scanning was conducted in both the perpendicular 1R13 (Fa1l2006 and parallel directions around the obstructing lug with the scan boundaries maximized by Outage) visually-assisted positioning of the remote examination head so that the scan starts and stops were as close to the core support lug as possible.
11201-V6-001-W07 81.21 74.1% The UT examination of this circumferential weld was limited by the proximity of the peripherally-located bottom-mounted inspection (8MI) tubes. Scanning was conducted 1R13 (Fa1l2006 between the obstructing tubes with the scan boundaries maximized by visually-assisted Outage) positioning of the remote examination head so that the scan starts and stops were as close to the 8MI tubes as possible.
El-3
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR 50.55a(g)(5)(iii)
RR-49 Version 2.0 TABLE RR-49 Weld Number I ASME Examined Item Coverage Basis for Limited Coverage 21201-V6-001-W06 81.11 78.4% The UT examination of this circumferential weld was limited by the proximity of six RPV core support lugs. Scanning was conducted between and below the obstructing lugs with the 2R12 (Spring 2007 scan boundaries maximized by visually-assisted positioning of the remote examination head Outage) so that the scan starts and stops were as close to the core support luas as possible.
21201-V6-001-W07 81.21 74.1% The UT examination of this circumferential weld was limited by the proximity of the peripherally-located bottom-mounted inspection (8MI) tubes. Scanning was conducted 2R12 (Spring 2007 between the obstructing tubes with the scan boundaries maximized by visually-assisted Outage) positioning of the remote examination head so that the scan starts and stops were as close to the 8MI tubes as possible.
El-4
Vogtle Electric Generating Plant - Units 1 and 2 Second 10-Year Intervallnservice Inspection Program Submittal of Relief Requests Enclosure 2 Relief Request RR-50 Class 2 Vessel Weld Examinations
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR SO.SSa(g)(S)(iii)
RR-SO Version 2.0 Plant Site Vogtle Electric Generating Plant - Units 1 and 2 Unit:
Interval 2 nd lSI Interval- May 31, 1997 through May 30, 2007 Interval Dates:
Requested 10 CFR 50.55a(g)(5)(iv) states: 'Where an examination requirement by Date for the code or addenda is determined to be impractical by the licensee and Approval and is not included in the revised inservice inspection program as permitted Basis by paragraph (g)(4) of this section, the basis for this determination must be demonstrated to the satisfaction of the Commission not later than 12 months after the expiration of the initial 120-month period of operation from start of facility commercial operation and each subsequent 120 month period of operation during which the examination is determined to be impractical." Hence, SNC is asking for approval as soon as possible in order to close-out the second lSI interval activities.
ASME Code Class 2, ASME Section XI, Code Category C-B, Item No. C2.21, for Components Class 2 vessel welds as shown on Table RR-52.
Affected:
Applicable ASME Section XI, 1989 Edition with no addenda.
Code Edition and Addenda:
Applicable Table IWB-2500-1, Examination Category C-B, Item C2.21 requires Code examination per Figure IWC-2500-4(a), (b) or (c).
Requirements:
Impracticality Physical limitations due to geometric configuration of the welded areas of restricted coverage of the examination volume as required by the figures Compliance: referenced above. The five welds with limitations include the RHR heat exchanger (1205 system) and the Class 2 portion of the steam generator 4 (1201 system). The limitations are described in Table RR
- 50. Figure RR-50-1 shows the Vogtle RHR heat exchanger nozzle configuration which includes the reinforcing plate on the 10 of the nozzle as compared to the ASME Code Figure IWC-2500-4(c) which shows the reinforcing plate on the 00. Figure RR-50-2 shows the Auxiliary Feedwater Nozzle on Unit-2 steam generator 4. In each case, the welds were examined to the fullest extent practical. Appreciably increasing coverage was impractical due to the limitations described in the table.
E2-1
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR 50.55a(g)(5)(iii)
RR-50 Version 2.0 Burden To obtain more coverage, the design of the Unit-1 and -2 RHR heat Caused by exchangers would need to be changed such that:
Compliance
- 1. The nozzle to shell weld is located on the shell as shown in ASI\I1E Section XI, Figure IWC-2500-4(a), plus
- 2. The nozzle 00 near the weld would need to have sufficient flatness to permit scanning to be performed parallel to the weld looking for axial cracking, plus
- 3. The nozzle to shell weld would need to be ground smooth to permit scanning over the weld.
To obtain more coverage, the design of the Unit-2 steam generators would need to be changed such that:
The Auxiliary Feedwater nozzle 00 near the weld would need to have sufficient flatness to permit scanning to be performed parallel to the weld looking for axial cracking.
To change the design of the Vogtle RHR heat exchangers and the steam generators to obtain more examination coverage would be a significant burden on SNC.
Proposed Surface and ultrasonic examinations were performed on these welds.
Alternative The inspection volume of all five welds was interrogated with UT from one and Basis for side of the weld looking for circumferential cracking. In addition, VT-2 Use: visual examinations associated with the Class 2 leakage test are performed once an lSI period on all of these welds. The visual examinations have not found any through-wall flaws on the RHR heat exchangers or the steam generator. These examinations and tests provide reasonable assurance of structural integrity. There is no anticipated impact upon the overall plant quality and safety, and the granting of relief should not jeopardize the health and safety of the public.
Therefore, pursuant to the requirements of 10 CFR 50.55a (g)(5)(iii), relief is requested from performing the 100% vOlumetric examination requirements of the applicable Category C-B welds listed in Table RR-50.
Duration of The proposed relief request is applicable for the 2nd lSI Interval.
Proposed Relief Request:
Precedents: The physical limitations described in this relief request are very similar to Vogtle RR-14, Revision 3 which was approved by the NRC on June 20, 2001.
References:
NRC SER TAC Nos. MB0603 and MB0604.
Status: Awaiting NRC approval.
E2-2
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR 50.55a(g}(5}(iii}
RR-50 Version 2.0 TABLE RR-50 Weld Number I ASME Examination Examined Item Coverage Limitations Results 11205-E6-002-W04 C2.21 100% PT This is a stainless steel heat exchanger. Due to the configuration (see No Recordable 41.5% UT Figure RR-50-1), the axial scans looking for circumferential cracking Indications 1R12 (Spring were performed only from the nozzle side. Axial scan coverage from 2005 Outage) the nozzle side was complete; however, because the material is stainless steel, only 50% of the examination volume was conservatively credited for examination. There were limited circumferential scans looking for axial cracking due to the weld configuration. 100% surface examination performed.
11205-E6-002-W05 C2.21 100% PT This is a stainless steel heat exchanger. Due to the configuration (see No Recordable 41.5% UT Figure RR-50-1), the axial scans looking for circumferential cracking Indications 1R12 (Spring were performed only from the nozzle side. Axial scan coverage from 2005 Outage) the nozzle side was complete; however, because the material is stainless steel, only 50% of the examination volume was conservatively credited for examination. There were limited circumferential scans looking for axial cracking due to the weld configuration. 100% surface examination performed.
21205-E6-002-W04 C2.21 100% PT This is a stainless steel heat exchanger. Due to the configuration (see Code-allowable 41.5% UT Figure RR-50-1), the axial scans looking for circumferential cracking PT indication; 2R12 (Spring were performed only from the nozzle side. Axial scan coverage from No Recordable 2007 Outage) the nozzle side was complete; however, because the material is UT Indications stainless steel, only 50% of the examination volume was conservatively credited for examination. There were limited circumferential scans looking for axial cracking due to the weld configuration. 100% surface examination performed.
E2-3
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR 50.55a(g)(5)(iii)
RR*50 Version 2.0 TABLE RR-50 Weld Number I ASME Examination Examined Item Coverage Limitations Results 21205-E6-002-W05 C2.21 100% PT This is a stainless steel heat exchanger. Due to the configuration (see No Recordable 41.5% UT Figure RR-50-1), the axial scans looking for circumferential cracking PT Indications; 2R12 (Spring were performed only from the nozzle side. Axial scan coverage from Code-allowable 2007 Outage) the nozzle side was complete; however, because the material is UT indication stainless steel, only 50% of the examination volume was conservatively credited for examination. There were limited circumferential scans looking for axial cracking due to the weld configuration. 100% surface examination performed.
21201-B6-004-W26 C2.21 100% MT This is a carbon steel steam generator. Due to the configuration (see No Recordable 50%UT Figure RR-50-2), the axial scans looking for circumferential cracking Indications 2R10 (Spring were performed only from the vessel side. Axial scan coverage from 2004 Outage) the vessel side was complete. Circumferential scans looking for axial cracking were limited to the weld and vessel side. 100% surface examination performed.
E2-4
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR SO.SSa{g){S){iii)
RR-SO Version 2.0 Reinforcing Plate 1_~f1 Thick
//
/
Nozzle ___' '~~,~[t Welds /'
./
J W04& W05/
Figure RR-50-1 for RHR Heat Exchanger Nozzle Welds AFW Nozzle IDS
, Vessel Shell I US
, I Figure RR-50-2 for Steam Generator 4 Nozzle Weld E2-5
Vogtle Electric Generating Plant - Units 1 and 2 Second 10-Year Intervallnservice Inspection Program Submittal of Relief Requests Enclosure 3 Relief Request RR-51 Class 2 Residual Heat Removal Heat Exchanger Shell Welds
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR 50.55a{g)(5)(iii)
RR-51 Version 2.0 Plant Site Vogtle Electric Generating Plant - Units 1 and 2 Unit:
Interval 2nd lSI Interval - May 31, 1997 through May 30, 2007 Interval Dates:
Requested 10 CFR 50.55a(g)(5)(iv) states: "Where an examination requirement by Date for the code or addenda is determined to be impractical by the licensee and Approval and is not included in the revised inservice inspection program as permitted Basis by paragraph (g)(4) of this section, the basis for this determination must be demonstrated to the satisfaction of the Commission not later than 12 months after the expiration of the initial 120-month period of operation from start of facility commercial operation and each subsequent 120 month period of operation during which the examination is determined to be impractical." Hence, SNC is asking for approval as soon as possible in order to close-out the second lSI interval activities.
ASME Code Class 2, ASME Section XI, Code Category C-A, Item Number C1.1 0, for Components Class 2 vessel shell welds as shown in Table RR-51.
Affected:
Applicable Code Edition ASME Section XI, 1989 Edition with no addenda.
and Addenda:
Applicable Table IWB-2500-1, Examination Category C-A, Item C1.1 0 requires Code Requirements: examination per Figure IWC-2500-1.
Impracticality Physical limitations due to geometric configuration of the welded areas of restricted coverage of the examination volume as required by the figure Compliance: referenced above. The two welds with limitations are on the Residual Heat Removal (RHR) heat exchanger and are described in Table RR-51.
Figure RR-51 shows the typical representation of the limited weld examinations. In each case, the welds were examined to the fullest extent practical. Appreciably increasing coverage was impractical due to the limitations described in the table.
Burden To obtain more coverage, the design of the Unit-1 and -2 RHR heat Caused by exchangers would need to be changed such that:
Compliance 1. The circumferential weld joining the flange to the heat exchanger shell would have to permit access for ultrasonic examination from the flange side. In particular, the flange 00 near the weld would need to be flat to permit scanning to be performed parallel to the weld looking for axial cracking, plus
- 2. The nozzle to shell weld would need to be ground smooth to permit scanning over the weld.
E3-1
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR SO.SSa(g)(S)(iii)
RR-S1 Version 2.0 To change the design of the Vogtle RHR heat exchangers to obtain more examination coverage would be a significant burden on SNC.
Proposed At least 74% of the examination volume of each weld was interrogated Alternative using two beam directions looking for circumferential cracking.
and Basis for Additionally, at least 95% of the examination volume of each weld was Use: interrogated using one beam direction looking for circumferential cracking. In addition, VT-2 visual examinations associated with the Class 2 leakage test are performed once an lSI period on all of these welds.
The visual examinations have not found any through-wall flaws on the RHR heat exchangers. These examinations and tests provide reasonable assurance of structural integrity. There is no anticipated impact upon the overall plant quality and safety, and the granting of relief should not jeopardize the health and safety of the public. Therefore, pursuant to the requirements of 10 CFR 50.55a (g)(5)(iii), relief is requested from performing the 100% volumetric examination requirements of the applicable Category C-A welds listed in Table RR-51.
Duration of Proposed Relief The proposed relief request is applicable for the 2 nd lSI Interval.
Request:
Precedents: The physical limitations described in this relief request are very similar to Vogtle RR-14, Revision 3 which was approved by the NRC on June 20, 2001.
References:
NRC SER TAC Nos. MB0603 and MB0604.
Status: Awaiting NRC approval.
E3-2
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR 50.55a(g)(5)(iii)
RR-51 Version 2.0 TABLE RR-51 Weld Number I ASME Examination Examined Item Coverage Limitations Results 11205-E6-002-W01 CUO 55%UT No examination coverage from the flange side due to the configuration. No Recordable Limited clockwise and counterclockwise scans (for axial flaws) on the Indications 1R10 (Spring weld due to the weld configuration. See Figure RR-51 for coverage.
2002 Outage) 21205-E6-002-W01 CUO 56%UT No examination coverage from the flange side due to the configuration. UT indications Limited clockwise and counterclockwise scans (for axial flaws) on the dueto 2R09 (Fall 2002 weld due to the weld configuration. See Figure RR-51 for coverage. Geometry Outage)
E3-3
SOUTHERN NUCLEAR OPERATING COMPANY PROPOSED RELIEF REQUEST IN ACCORDANCE WITH 10 CFR 50.55a(g)(5)(iii)
RR-51 Version 2.0 FLANGE I DOWNSTREAM Figure RR-51 for RHR Heat Exchanger Shell Welds E3-4