ML12321A096
| ML12321A096 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 01/30/2013 |
| From: | Markley M Plant Licensing Branch IV |
| To: | Entergy Operations |
| Kalyanam N | |
| References | |
| TAC ME8270, TAC ME8275 | |
| Download: ML12321A096 (17) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 January 30, 2013 Vice President, Operations Arkansas Nuclear One Entergy Operations, Inc.
1448 S.R. 333 Russellville, AR 72802
SUBJECT:
ARKANSAS NUCLEAR ONE, UNIT 2 - REQUEST FOR RELIEF NOS. AN02-ISI-008 AND AN02-ISI-013 FOR THIRD 10-YEAR INTERVAL INSERVICE INSPECTION (TAC NOS. ME8270 AND ME8275)
Dear Sir or Madam:
By letter dated March 26,2012, Entergy Operations, Inc. (the licensee), proposed Request for Relief (RR) Nos. AN02-ISI-008 and AN02-ISI-013 (in addition to four other RRs) from certain requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (ASME Code), under the provisions of Title 10 of the Code of Federal Regulations (10 CFR), paragraph 50.55a(g)(5)(iii), for the third 10-year inservice inspection (lSI) program for Arkansas Nuclear One (ANO), Unit 2. Additionally, in response to two U.S. Nuclear Regulatory Commission (NRC) requests for additional information dated July 18, 2012, the licensee supplemented the application by two letters, both dated September 4,2012, for RRs AN02-ISI-008 and AN02-ISI-013.
The ANO, Unit 2, third 10-year lSI interval ended on March 25, 2010. The licensee extended the third 1O-year lSI interval by 1 year in accordance with ASME Code,Section XI, Paragraph IWA-2430 for the 2R21 (21 st) refueling outage.
RR No. AN02-ISI-008 covers the nozzle-to-vessel welds and inner radii. In its letter dated March 26, 2012, the licensee stated that during ultrasonic examination, 100 percent coverage of the required examination volume could not be obtained and. due to the geometric configuration of the cO,mponents and the close proximity of other structures which limited scan paths, the use of approved beam angles in the axial and circumferential direction were not able to achieve greater than 90 percent Code-required volume.
Similarly, RR No. AN02-ISI-013 covers the feedwater nozzle-to-shell weld where 100 percent coverage of the required examination volumes could not be obtained. Due to the close proximity of one of the steam generator insulation brackets, 100 percent examination of the Code-required volume was not achieved.
Based on information provided by the licensee, the NRC staff concludes that it is impractical for the licensee to meet the ASME Code-required 100 percent volumetric examination coverage for the nozzle-to-vessel welds and inner radii and feedwater nozzle-to-shell weld. The licensee considered radiographic testing (RT); however, RT was not practical on these types of nozzle-to vessel weld configurations, which prevent placement of the film and exposure source. The
-2 licensee has examined these welds to the extent practical and will continue to perform pressure testing on the subject components as required by the ASME Code.
The NRC staff also concludes that the examinations performed to the extent practical on the subject welds provide reasonable assurance of structural integrity of the subject welds. Based on the volumetric coverage obtained for the subject welds, and considering the licensee's performance of UT techniques employed to maximize this coverage, the NRC staff also concludes that if significant service-induced degradation had occurred, evidence of it would have been detected by the examinations that were performed.
The NRC staff has determined that granting relief pursuant to 10 CFR 50.55a(g)(6)(i) 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 due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility. Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(g)(6)(i). Therefore, the NRC staff grants relief from the specified ASME Code,Section XI, examination coverage requirements of the subject welds contained in RRs AN02-ISI-008 and AN02-ISI-013 for the ANO, Unit 2, 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.
The NRC staffs safety evaluation is enclosed.
Sincerely, Michael T. Markley, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-368
Enclosure:
As stated 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 INSERVICE INSPECTION INTERVAL REQUEST FOR RELIEF NOS. AN02-ISI-008 AND AN02-ISI-013 ARKANSAS NUCLEAR ONE, UNIT 2 ENTERGY OPERATIONS, INC.
DOCKET NO. 50-368
1.0 INTRODUCTION
By letter dated March 26, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12086A293), Entergy Operations, Inc. (the licensee), proposed Request for Relief (RR) Nos. AN02-ISI-008 and AN02-ISI-013 (in addition to four other RRs) from certain requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (ASME Code), under the provisions of Title 10 of the Code of Federal Regulations (10 CFR), paragraph 50.55a(g)(5)(iii), for the third 10-year inservice inspection (lSI) program for Arkansas Nuclear One (ANO), Unit 2. Additionally, in response to two U.S. Nuclear Regulatory Commission (NRC) requests for additional information dated July 18, 2012 (ADAMS Accession Nos. ML12201A274 and ML12201A270, respectively), the licensee supplemented the application by two letters, both dated September 4, 2012 (ADAMS Accession Nos.
ML12249A252 and ML12249A254, respectively), for RR Nos. AN02-ISI-008 and AN02-ISI-013.
2.0 REGULATORY 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 preservice 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 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, which was incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-rnonth interval, subject to the limitations and modifications listed therein.
The regulations in 10 CFR 50.55a(g)(5)(iii), state, in part, that that licensees may determine that conformance with certain ASME Code requirements is impractical and that the licensee shall notify the Commission and submit information in support of the determination. Determination of impracticality in accordance with this section must be based on the demonstrated limitations experience when attempting to comply with the code requirements during the lSI interval for Enclosure
-2 which the request is being submitted. Requests for relief made in accordance with this section must be submitted to the NRC no later than 12 months after the expiration of the initial 120-month inspection interval or subsequent 120-month inspection interval for which relief is sought.
The regulations in 10 CFR 50.55a(g)(6)(i) state that'lt]he Commission will evaluate determinations under paragraph (g)(5) of this section that code requirements are impractical.
The Commission may grant such relief and may impose such alternative requirements 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 giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility:'
The licensee has requested relief from ASME Code requirements pursuant to 10 CFR 50.55a(g)(6)(i). The ASME Code of record for the ANO, Unit 2, third 10-year lSI interval program is the 2001 Edition through the 2003 Addenda of Section XI of the ASME Code. ANO, Unit 2, also uses the 1995 Edition through the 1996 Addenda for ultrasonic testing (UT) examination requirements. The ANO, Unit 2, third 10-year lSI interval ended on March 25, 2010. The licensee extended the third 10-year lSI interval by 1 year in accordance with ASME Code,Section XI, Paragraph IWA-2430 for the 2R21 (21st) refueling outage.
3.0 TECHNICAL EVALUATION
3.1 RR No. AN02-ISI-008 3.1.1 ASME Code Components ASME Code,Section XI, Examination Category 8-D, Item Numbers 81.30 and 83.140 in Steam Generator (SG) Full Penetration Welded Nozzle-to-Vessel Welds.
For a list of components, see Table 1, "Limited 8-D Examinations;' on pages 7-10 of this safety evaluation (SE), which was reproduced from the licensee's submittal dated March 26,2012.
3.1.2 ASME Code Requirements ASME Code,Section XI, Examination Category 8-D, Items 83.110 and 83.140 requires 100 percent volumetric examination, as defined by ASME Code,Section XI, Figures IW82500-7 (a) through (d), as applicable, of full penetration ASME Code, Class 1 nozzle-to-vessel welds on the SG. ASME Code Case N-460, "Alternative Examination Coverage for Class 1 and Class 2 Welds,Section XI, Division 1:' as an alternative approved for use by the NRC in Regulatory Guide (RG) 1.147, Revision 16, "Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1;' October 2010 (ADAMS Accession No. ML101800536), states that a reduction in examination coverage due to part geometry or interference for any Class 1 and 2 weld is acceptable provided that the reduction is less than 10 percent (Le., greater than 90 percent examination coverage is obtained).
The licensee has invoked ASME Code Case N-593, "Alternative Examination Requirements for Steam Generator Nozzle to Vessel Welds,Section XI, Division 1:' This ASME Code Case requires that the examination volume indicated in Figure 1 of ASME Code Case N-593 shall be
-3 used in lieu of the examination volume specified in Table IWAB-2500-1, Examination B-O, where the contour of this head design prohibits full examination coverage of the A-B-C-O-E-F-G-H examination volume from two directions. This volume shall be examined to the extent practical. ASME Code Case N-593 has been conditionally approved as an alternative for use by the NRC in RG 1.147, Revision 16. The RG 1.147, Revision 16, condition for ASME Code Case N-593 states that:
Essentially 100 percent (not less than 90 percent) of the examination volume A-B-C-O-E-F-G-H must be inspected.
3.1.3 Licensee's Basis for Relief Request (as stated by the licensee)
During ultrasonic [(UT)] examination of the nozzle-to-vessel welds and inner radii listed in Table 1 below, 100% coverage of the required examination volume could not be obtained.
Due to the geometric configuration of the components and the close proximity of other structures which limited scan paths, the use of approved beam angles in the axial and circumferential direction were not able to achieve greater than 90%
code required volume. See Table 1 below for additional information.
Radiography is not practical on these types of nozzle-to-vessel weld configurations, which prevent placement of the film and exposure source. To effectively perform any significant additional Code allowable ultrasonic examinations, modification and/or replacement of the component would be required. The examinations performed on the subject items in addition to the examination of other vessel welds contained in the Inservice Inspection Program would detect generic degradation, if it existed, demonstrating an acceptable level of integ rity .
Additional information was provided by the licensee in its letter dated September 4, 2012, for RR No. AN02-ISI-008 for components in Table 1 contained in the licensee's submittal dated March 26, 2012, identified as Numbers03-005, 03-006, and 03-007 associated with Figures 5, 6, and 7 1 .(as stated)
The limitation is due to the configuration on the nozzle side of the component.
These examinations were performed in 2003. During that time, the vessel weld ultrasonic examination procedure did not specifically require scanning down a nozzle taper in a best effort attempt to enhance coverage; therefore; scanning was only credited from a single side e.g., 50%.
The Figures 5, 6, and 7 contained in the Request for Relief AN02-ISI-008 are typical of the examination scans performed in the 2006 inspection and depict scans down the nozzle taper. Those scans down the nozzle taper were not performed in 2003 on components03-005,03-006 and 03-007.
Figures 5, 6, and 7 are not included in this SE. See the licensee's submittal dated September 4, 2012, for the subject figures.
-4 During the development of the response to this request it was determined that Request for Relief AN02-ISI-008, Figures 5, 6, and 7 were incorrect. They were actually a copy of earlier figures in the same request. The correct figures [5, 6, and 7] are shown below and are typical of the examination scans performed in the 2003 time frame.
For Item Nos.03-005, 03-006, and 03-007, additional clarifying information was provided in the licensee's e-mail datedSeptember19.2012(ADAMSAccessionNo.ML12263A182). which stated, in part, that Welds03-005, 03-006 & 03-007 were volumetrically examined in 2003 to satisfy rd the 3 lSI interval compliance requirements of IWB-2500, Table 1. The NDE
[nondestructive examination] procedure was written to the ASME Section XI 1986 code. These were the Nozzle to Extension Piece welds on the then new"/f.
steam generator. They were scanned from the extension piece side only resulting in 50% coverage of the code required examination volume. This exam, at the time, was compliant with the procedures and the code of record.
rd In 2006 we examined welds04-005,04-006 & 04-007. These 3 lSI interval examinations were for the "8' steam generator Nozzle to Extension Piece welds (sister welds to the 03-xxx welds). They were volumetrically examined in accordance with ASME Section XI, 1995 ed [Edition] wI [with] 96 ad [Addenda].
These welds were scanned from both sides of the weld and additional code coverage was achieved. However, since essentially 100% of these welds could not be examined either, they were included in AN02-RR-008 also.
rd All of the above welds were only examined once during the 3 interval and no relief requests previous to AN02-RR-008 were submitted for limited examination coverage.
3.1.4 Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination at this time. The licensee considered radiographic testing (RT); however, it concluded that RT was not practical on these types of nozzle-to-vessel weld configurations, which prevent placement of the film and exposure source.
The licensee has examined these welds to the extent practical and will continue to perform pressure testing on the subject components as required by the ASME Code.
3.1.5 NRC Staff Evaluation The ASME Code requires 100 percent volumetric examination of ASME Code, Class 1 Nozzle to-Extension Pipe Welds04-005,04-006, and 04-007. In addition, the ASME Code requires that the volumetric examinations be conducted from both sides of these pressure retaining welds. However, the design configurations of the subject nozzle-to-extension pipe welds limit access for UT scanning primarily to the vessel side of the welds. In order to effectively increase the examination coverage, the subject welds would require design modifications or replacement.
The licensee did not propose an alternative examination at this time. The licensee considered
- 5 RT; however, it concluded that RT was not practical on these types of nozzle-to-vessel weld configurations, which prevent placement of the film and exposure source. To require the licensee to perform the ASME Code-required examinations would place a burden on the licensee.
The SG Outlet Nozzle-to-Extension Pipe Welds04-005,04-006, and 04-007, shown in Table 1 on pages 7-10 of this SE, are constructed of carbon steel material, with stainless steel cladding on the inside surface. This design geometry limits ASME Code-required UT angle beam examinations to be performed primarily from the vessel side of the welds. As shown on the sketches and technical descriptions included in the licensee's submittals, examinations of the subject welds have been completed to the extent practical with aggregate coverage of the ASME Code-required volumes 61.5, 61.5, and 54.69 percent, respectively, as shown in Table 1 on pages 7-10 of this SE. Manual UT examinations were conducted using ASME Code,Section V, Article 4 techniques and included O-degree longitudinal, and 45-degree and 60-degree shear waves primarily from the vessel side. limitations were caused by the configuration of the nozzle-to-extension pipe design, and proximity to nozzle outside diameter radius sections, or blend areas. The examination volumes included the weld and base materials near the inside surface of the weld jOints, which are typically the highest regions of stress, and where one would expect degradation sources to be manifested should they occur.
No unacceptable indications were recorded during these examinations. Although UT scans were primarily limited to the vessel side, recent studies have found that inspections conducted through carbon steel are equally effective whether the UT waves have only to propagate through the base metal, or have to also propagate through the carbon steel weldmene*
Therefore, due to the fine-grained carbon steel microstructures, it is expected that the UT techniques employed would have detected structurally significant flaws that may have occurred on either side of the subject welds.
The ASME Code requires 100 percent volumetric examination of ASME Code, Class 1 SG Nozzle Inner Radius Welds 03-005IR, 03-0061IR, 03-007IR, 04-005IR, 04-0061R, and 04 0071R. In addition, the ASME Code requires that the volumetric examinations be conducted from both sides of these pressure retaining welds. However, the design configurations of the subject inter radius welds limit access for UT scanning primarily to the vessel side of the welds.
In order to effectively increase the examination coverage, the subject welds would require design modifications or replacement. This would place a burden on the licensee.
The SG Nozzle Inner Radius Welds 03-0051R, 03-00611R, 03-0071R, 04-0051R, 04-0061R, and 04-0071R shown in Table 1 below are constructed of carbon steel material, with stainless steel cladding on the inside surface. This design geometry and four integral attachments each 4.25-inch x 3.75-inch in size, located on the SG lower head limits ASME Code-required UT angle beam examinations to be performed primarily from the vessel side of the welds. As shown on the sketches and technical descriptions included in the licensee's submittals, examinations of the subject welds have been completed to the extent practical with aggregate coverage of the ASME Code-required volumes 88, 88, 90, 88, 88, and 90 percent, respectively, as shown in Table 1 below. Manual UT examinations were conducted using ASME Code,Section V, Article 4 techniques and included 25-degree shear, 90-degree skew angle, 35-degree shear at
+120-degree and -120-degree skew angles, 55-degree shear at +22-degree and degree 2 P. G. Heasler and S. R. Doctor, 1996. Piping Inspection Round Robin, NUREG/CR-5068, PNNL-10475.
U.S. Nuclear Regulatory Commission, Washington, DC.
- 6 skew angles, and 70-degree at +81-degree and degree skew angels waves primarily from the vessel side. Limitations were caused by the configuration of the nozzle configuration and four integral attachments. The examination volumes included the weld and base materials inside surface of the weld jOints, which are typically the highest regions of stress, and where one would expect degradation sources to be manifested should they occur. No indications were recorded during these examinations.
The SG Outlet Nozzle-to-Extension Pipe Welds03-005,03-006, and 03-007 shown in Table 1 below are constructed of carbon steel material, with stainless steel cladding on the inside surface. This design geometry limits ASME Code-required UT angle beam examinations to be performed primarily from the pipe side of the welds. As shown on the sketches and technical descriptions included in the licensee's submittals, examinations of the subject welds have been completed to the extent practical with aggregate coverage of the ASME Code-required volumes 50, 50, and 50 percent, respectively, as shown in Table 1 below. Manual UT examinations were conducted using ASME Code,Section V, Article 4 techniques and included 45-degree, O-degree, 60-degree, and 70-degree longitudinal and shear waves primarily from the extension pipe side. By letter dated September 4,2012, in response to the NRC staff request for additional information (RAI) dated July 18,2012 (ADAMS Accession No. ML12201A274), the licensee noted that these examinations were performed during 2003, and that the vessel weld UT examination procedure did not specifically require scanning down a nozzle taper in a best effort attempt to enhance coverage, thus the scanning was only credited from a single side (e.g., 50 percent as noted above).
Limitations were caused by the configuration of the nozzle side of the component. The examination volumes included the weld and base materials near the inside surface of the weld joints, which are typically the highest regions of stress, and where one would expect degradation sources to be manifested should they occur. No unacceptable indications were recorded during these examinations. Although UT scans were primarily limited to the extension pipe, recent studies have found that inspections conducted through carbon steel are equally effective whether the UT waves have only to propagate through the base metal, or have to also propagate through the carbon steel weldmene. Therefore, due to the fine-grained carbon steel microstructures, it is expected that the UT techniques employed would have detected structurally significant flaws that may have occurred on either side of the subject welds.
The licensee has shown that it is impractical to meet the ASME Code-required 100 percent volumetric examination coverage for the subject SG nozzle-to-extension and nozzle inter radius welds due to the nozzles'designs and in the case of the subject nozzle inter radius welds the nozzle configuration and four integral attachments. Based on the volumetric coverage obtained for the subject welds, and considering the licensee's performance of UT techniques employed to maximize this coverage, the NRC staff concludes that that if significant service-induced degradation had occurred, evidence of it would have been detected by the examinations that were performed. The staff also concludes that the examinations performed to the extent practical on the subject welds provide reasonable assurance of structural integrity of the subject welds.
3 P. G. Heasler and $. R. Doctor, 1996. Piping Inspection Round Robin, NUREG/CR-5068, PNNL-10475, U.S. Nuclear Regulatory Commission, and Washington. DC.
-7
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Table 1 for RR No. AN02-ISI-008 Limited B-D Examinations Component Description ~-~
Additional Information i Estimated %
Coverage of Item Item Exam Method Surface Exam Comp.ID Code Examination Summary Scan Plan Search Units Number Description and Limitations Examination Results Required Volume ~-~
83.130 04-005 Steam Generator 61.5 Component was scanned See the attached Manual UT Wave modalities are None required. No (SG) "8" Primary from both sides; however, sketch (Figure 1) longitudinal and indications A detailed sketch shear. were Outlet Nozzle-to scanning was limited from the derived from UT Extension Pipe (Figure 1) of the recorded.
nozzle side due to the examination report limitation is Insonification angles Circumferential component configuration. ISI-UT-06-045 on included with the included 0*, 45°, and Weld file at AND.
~-~ ~-~
scan plan 60*.
83.130 04-006 SG "8" Primary 61.5 Component was scanned See the attached Manual UT Wave modalities are None required. No Outlet Nozzle-to from both sides; however, sketch (Figure 2) longitudinal and indications Extension Pipe A detailed sketch shear. were scanning was limited from the derived from UT (Figure 2) of the recorded.
C i rcu mferential nozzle side due to the examination report limitation is Insonification angles Weld component configuration. ISI-UT-06-046 on included with the included 0*, 45*, and File at ANO.
scan plan. 60*.
83.130 04-007 Extension Pipe 54.69 Component was scanned See the attached Manual UT Wave modalities are None required. No to-SG "8" from both sides; however, sketch (Figure 3) longitudinal and indications Primary Inlet A detailed sketch shear. were scanning was limited from the derived from UT (Figure 3) of the recorded.
Nozzle nozzle side due to the examination report limitation is Insonification angles Circumferential component configuration. ISI-UT-06-049 on included with the included 0°, 45°, and Weld file atANO.
~-~
scan plan. 60*.
83.140 03-0051R SG "A" Primary 88 Scanning was performed See the attached Manual UT Wave modality and None required. No Outlet Nozzle from the vessel side only due sketch (Figure 4) insonification angles indications Inner Radii derived from UT Four integral included 25' shear at were to component configuration.
examination reports attachments, each 90' skew angle; 35' recorded.
4.25" x 3.75" in size, shear at +120' and ISI-UT-06 located on the SG 120' skew angles; 059and1SI-UT-06 lower head, reduced 55' shear at +22*
060 and UT examination and -22' skew procedure CEP-NDE-0485 on file at coverage by 12% angles and 70' shear ANO. at +81' and -81" skew angles.
-8 Table 1 for RR No. AN02-ISI-008 Limited B-D Examinations Component Description Additional Information Estimated %
Coverage of Item Item Exam Method Surface Exam Comp.ID Code Examination Summary Scan Plan Search Units Number Description and Limitations Examination Results Required Volume 83.140 03-006IR SG "A" Primary 88 Scanning was performed See the attached Manual UT Wave modality and None required. No Outlet Nozzle from the vessel side only due sketch (Figure 4) insonification angles indications derived from UT Four integral included 25' shear at were Inner Radii to component configuration.
examination reports attachments, each 90' skew angle; 35' recorded.
ISI-UT 061 and 4.25" x 3.75" in size, shear at +120' and located on the SG 120' skew angles; ISI-UT 062 and UT procedure CEP- lower head, reduced 55' shear at +22*
examination and -22' skew NDE-0485 on file at I coverage by 12% angles and 70' shear ANO.
at +81* and -81' skew angles.
83.140 03- 0071R SG "A" Primary 90 Scanning was performed from See the attached Manual UT Wave modality and None required. No Inlet Nozzle the vessel side only due to sketch (Figure 4) insonification angles indications Inner Radii derived from UT Four integral included 25* shear at were com ponent configuration.
examination reports attachments, each 90' skew angle; 35' recorded.
IS1-UT 063 and 4.25" x 3.75" in size, shear at + 120" and located on the SG 120' skew angles; ISI-UT 064 and lower head, reduced 55" shear at +22' UT procedure CEP-examination and -22' skew angles NDE-0485 on file at coverage by 10% and 70* shear at ANO.
+81' and -81" skew angles.
83.140 04- 0051R SG "8" Primary 88 Scanning was performed See the attached Manual UT Wave modality and None required. No Outlet Nozzle from the vessel side only due sketch (Figure 4) insonification angles indications Inner Radii derived from UT Four integral included 25' shear at were to component configuration.
examination reports attachments, each 90* skew angle; 35* recorded.
4.25" x 3.75" in shear at + 120* and ISI-UT 050 and size, located on the 120* skew angles; ISI-UT 051 and UT procedure CEP- SG lower head, 55* shear at +22*
NDE-0485 on file at reduced and _22* skew angles ANO. examination and 70* shear at coverage by 12% +81' and _81* skew angles.
-9 Table 1 for RR No. AN02-ISI-008 Limited B-D Examinations Component Description Additional Information Estimated %
Coverage of Item Item Exam Method Surface Exam Comp.ID Code Examination Summary Scan Plan Search Units Number Description and Limitations Examination Results Required Volume S3.14O 04- 006IR SG "S" Primary 88 Scanning was performed from See the attached Manual UT Wave modality and None required. No Outlet Nozzle the vessel side only due to sketch (Figure 4) insonification angles indications Inner Radii Four integral component configuration. derived from UT included 25° shear at were attachments, each examination reports 90° skew angle; 35° recorded.
4.25" x 3.75" in size, ISI-UT 052 and shear at +120° and located on the SG ISI-UT 053 and 120° skew angles; lower head, 55° shear at +22*
UT procedure CEP-reduced and -22° skew angles NDE-0485 on file at examination ANO. and 70° shear at coverage by 12% +810 and -810 skew angles.
83.140 04 SG "S" Primary 90 Scanning was performed See the attached Manual UT Wave modality and None required. No 0071R Inlet Nozzle Inner from the vessel side only due sketch (Figure 4) insonification angles indications Radii Four integral to component configuration. derived from UT included 25° shear at were attachments, each 0 examination reports 90° skew angle; 35 recorded.
4.25" x 3.75" in ISI-UT 054 and shear at +120° and-size, located on the ISI-UT 055 and 120° skew angles; SG lower head, UT procedure CEP- 55° shear at +22° NDE-0485 on file at reduced and _22° skew angles examination ANO. and 70° shear at coverage by 10%
+81° and -81° skew angles.
S3.13O 03-005 SG "A" Primary 50 Component was scanned See the attached Manual UT Wave modalities are None required. No Relevant Outlet Nozzle* from extension pipe side only. sketch (Figure 5) longitudinal and indications to-Extension A detailed sketch derived from UT shear. Insonification were Pipe (Figure 5) of the examination report angles included 0°, recorded.
Circu mferential limitation is 2031SIUT011 and 45°, 60*, and 70°.
Weld included with the 2031SIUT012on file scan plan atAND.
- 10 Table 1 for RR No. AN02-ISI*OO8 I Limited B-D Examinations Component Description ---
Additional Information I Estimated "10 Coverage of Item Item Exam Method Surface Exam Comp.ID Code Examination Summary Scan Plan Search Units Number Description and Limitations Examination Results Required Volume 83.130 03-006 SG "A" Primary 50 Component was scanned See the attached Manual UT Wave modalities are None required. No Outlet Nozzle* from extension pipe side only. sketch (Figure 6) longitudinal and indications to-Extension derived from UT A detailed sketch shear. Insonification were Pipe examination report (Figure 6) of the angles included 0", recorded.
Circumferential 2031SIUT0130n file limitation is 45°,60°, and 70°.
Weld atANO. included with the scan plan.
83.130 03-007 Extension Pipe 50 Component was scanned See the attached Manual UT Wave modalities are None required. No to- SG "A" from extension pipe side only. sketch (Figure 7) longitudinal and indications Primary Inlet derived from UT A detailed sketch shear. Insonification were (Figure 7) of the recorded.
Nozzle examination report angles included 0°,
Circumferential 2031SIUT0150n file limitation is 45,60°, and 70°.
Weld atANO. included with the
"---- L __ --
scan plan. - - - ---
NOTE: Figures 1-7 referenced in this table are not reproduced for this SE. See Attachment 1 of the licensee's submittal dated March 26, 2012, for the subject figures.
- 11 3.2 RR No. AN02-ISI-013 3.2.1 ASME Code Components ASME Code,Section XI, Examination Category C-B, Item Numbers C2.21, SG"B'Nozzle-to Shell Weld 04-002.
For a list of components, see Table 1, "Limited C-B Examinations:' on page 13 of this SE, which was reproduced from the licensee's submittal dated March 26,2012.
3.2.2 ASME Code Requirements ASME Code,Section XI, Examination Category C-B, Item C2.21 requires 100 percent volumetric examination, as defined by ASME Code,Section XI, Figure IWC-2500-4 (a) or (b), as applicable, of full penetration ASME Code, Class 2 nozzle-to-vessel welds on the SG. ASME Code Case N-460, "Alternative Examination Coverage for Class 1 and Class 2 Welds,Section XI, Division 1:' as an alternative approved for use by the NRC in RG 1.147, Revision 16, states that a reduction in examination coverage due to part geometry or interference for any Class 1 and 2 weld is acceptable provided that the reduction is less than 10 percent (Le.,
greater than 90 percent examination coverage is obtained).
3.2.3 Licensee's Basis for Relief Request (as stated by the licensee)
During [UTJ examination of the [SG BJ Feedwater Nozzle-to-Shell Weld [04-002]
listed in Table 1, 100% coverage of the required examination volumes could not be obtained.
Due to the close proximity of one of the steam generator insulation brackets, located around the circumference of the vessel and directly below the Feedwater nozzles, scan paths from below the nozzle were impeded and 100% examination of the [ASME CodeJ required volume was not achieved. See Table 1 for additional information.
There are several insulation bracket rings located around the circumference of the steam generator. These brackets facilitate supporting the many insulation panels surrounding the circumference of the steam generator. Removal of the subject bracket requires removal of all insulation panels directly supported by that ring as well as removal or engineered rigging of all insulation rings and panels above the removed ring. The insulation rings are not bolted directly to the steam generator shell therefore each lower elevation ring helps support the above rings and insulation panels.
Radiography [(RT)J is not practical on these types of nozzle-to-vessel weld configurations, which prevent placement of the film and exposure source. To effectively perform any significant additional Code allowable ultrasonic examinations, modification and/or removal are replacement of the insulation ring would be required. The examinations performed on the subject items in addition to the examination of other vessel welds contained in the Inservice Inspection
- 12 program would detect generic degradation, if it existed, demonstrating an acceptable level of integrity.
3.2.4 Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination at this time. The licensee considered RT; however, it concluded that RT was not practical on these types of nozzle-to-vessel weld configurations, which prevent placement of the film and exposure source. The licensee examined these welds to the extent practical and will continue to perform pressure testing on the subject components as required by the ASME Code.
3.2.5 NRC Staff Evaluation The ASME Code requires 100 percent volumetric and surface examinations of Class 2 nozzle to-shell (or head) welds. However, for SG B Feedwater Nozzle-to-Shell Weld 04-002 complete examinations are limited due to the configuration of the shell-to-nozzle blend area and close proximity of an insulation bracket ring below the nozzle. In order to achieve greater volumetric coverage, the nozzle and bracket would have to be redesigned and modified. The licensee did not propose an alternative examination at this time. The licensee considered RT; however, it concluded that RT was not practical on these types of nozzle-to-shell weld configurations, which prevent placement of the film and exposure source. To require the licensee to perform the ASME Code-required examinations would place a burden on the licensee, therefore, the ASME Code volumetric examination is considered impractical.
The SG B Feedwater Nozzle-to-Shell Weld 04-002 shown in Table 1 below are constructed of carbon steel material, with stainless steel cladding on the inside surface. As shown in the sketches and technical descriptions included in the licensee's submittal, examination of SG B Feedwater Nozzle-to-Shell Weld 04-002 was performed to the extent practical, with the licensee obtaining 71.6 percent of the required examination volume. The shell-to-nozzle blend area and close proximity of an insulation bracket ring below the nozzle limited the examination from both sides of the weld. The licensee applied both 45-degree and 60-degree shear waves from both sides of the weld. The licensee also completed the full ASME Code-required surface examinations on the subject weld. No indications were noted during the volumetric and surface examinations of the subject weld.
The licensee has shown that it is impractical to meet the ASME Code-required 100 percent volumetric examination coverage for the subject nozzle-to-shell weld due to the nozzle's configuration and of an insulation bracket ring below the nozzle. However, based on the volumetric and full surface coverage obtained, the NRC staff concludes that if significant service-induced degradation had occurred, evidence of indications would be have been detected by the examinations performed. The NRC staff concludes that the examinations performed to the extent practical on the subject welds provide reasonable assurance of structural integrity of the subject welds.
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Table 1 for RR No. AN02-ISI-013 Limited CoB Examinations Component Description Additional Information Estimated ASME Coverage of Code Compo Item Code Exam Method Surface Exam Examination Summary Scan Plan Search Units Item 10 Description Required and Limitations Examination Results Number Volume Percent C2.21 04-002 Steam 71.6 This was a dual sided exam, See the attached Manual UT Wave modality used A surface No Generator "B" limited by the configuration of sketch (Figure 1) included shear. examination indications Feedwater the shell-to-nozzle blend area derived from A detailed sketch was performed were Nozzle-to-Shell and the close proximity of an (Figure 1) of the Insonification angles ultrasonic test (UT) and recorded.
Weld insulation bracket ring below examination report limitation is included 45° shear (S) documented on 0
the nozzle. ISI-UT-06-067 on included with the and 60 S. examination file at ANO. scan plan. report ISI-MT 06-039.
100% of the required surface was
-~~~
examined.
NOTE: Figure 1 referenced in this table is not reproduced for this SE. See Attachment 6 of the licensee's submittal dated March 26, 2012, for the subject figure.
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4.0 CONCLUSION
As set forth above, the NRC staff has determined that granting relief pursuant to 10 CFR SO.SSa(g)(6)(i) 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 due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.
Accordingly, the staff concludes that the licensee has adequately addressed all of the regulatory requirements setforth in 10 CFR SO.SSa(g)(6)(i). Therefore, the NRC staff grants relief from the specified ASME Code,Section XI, examination coverage requirements of the subject welds contained in RRs AN02-ISI-008 and AN02-ISI-013 for the ANO, Unit 2, third 1O-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: T. McLellan, NRRJDE/EPNB Date: January 30, 2013
-2 licensee has examined these welds to the extent practical and will continue to perform pressure testing on the subject components as required by the ASME Code.
The NRC staff also concludes that the examinations performed to the extent practical on the subject welds provide reasonable assurance of structural integrity of the subject welds. Based on the volumetric coverage obtained for the subject welds, and considering the licensee's performance of LIT techniques employed to maximize this coverage, the NRC staff also concludes that if significant service-induced degradation had occurred, evidence of it would have been detected by the examinations that were performed.
The NRC staff has determined that granting relief pursuant to 10 CFR 50.55a(g)(6)(i) 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 due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility. Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(g)(6)(i). Therefore, the NRC staff grants relief from the specified ASME Code,Section XI, examination coverage requirements of the subject welds contained in RRs AN02-ISI-008 and AN02-ISI-013 for the ANO, Unit 2, 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.
The NRC staffs safety evaluation is enclosed.
Sincerely, IRA by CFLyon forI Michael T. Markley, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-368
Enclosure:
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