ML092870544

Request for Relief No. 43 for the Second 10-Year Inservice Inspection Program Interval

ML092870544
Person / Time
Site:	Palo Verde  (NPF-074)
Issue date:	11/04/2009
From:	Markley M Plant Licensing Branch IV
To:	Edington R Arizona Public Service Co
Hall, J R, NRR/DORL/LPL4, 301-415-4032
References
TAC ME0375
Download: ML092870544 (18)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 4, 2009 Mr. Randall K. Edington Executive Vice President Nuclear/

Chief Nuclear Officer Mail Station 7602 Arizona Public Service Company P. O. Box 52034 Phoenix, AZ 85072-2034 SUB..IECT:

PALO VERDE NUCLEAR GENERATING STATION, UNIT 3 - REQUEST FOR RELIEF NO. 43 FOR THE SECOND 10-YEAR INSERVICE INSPECTION PROGRAM INTERVAL (TAC NO. ME0375)

Dear Mr. Edington:

By letter dated January 12, 2009, as supplemented September 17, 2009, Arizona Public Service Company (APS, the licensee) submitted Relief Request No. 43 (RR-43), requesting relief from certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) requirements at Palo Verde Nuclear Generating Station (Palo Verde), Unit 3, for the second 1O-year inservice inspection (lSI) program interval which ended on January 10, 2008.

RR-43 requests relief from certain weld examination requirements of ASME Code,Section XI that APS has considered impractical.

The staff of the U.S. Nuclear Regulatory Commission (NRC) has reviewed the licensee's submittal and determined that granting RR-43, pursuant to paragraph 50.55a(g)(6)(i) of Title 10 of the Code of Federal Regulations, 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. Relief is granted for the second 10-year lSI program interval at Palo Verde, Unit 3, based on the NRC staff's determination that the examination coverage requirements are impractical for the subject welds listed in RR-43, Parts A through E, and that the examinations performed to the extent practical provide reasonable assurance of structural integrity of the welds. The NRC staff has further determined that the VT-2 visual examinations for leakage provide reasonable assurance of leak integrity of the subject tubing in RR-43, Part E.

A copy of the related Safety Evaluation is enclosed. All other ASME Code,Section XI, requirements for which relief has not been specifically requested and approved remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.

R. Edington

- 2 If you have any questions, please contact Mr. Randy Hall at (301) 415-4032 or via email at randy.hall@nrc.gov.

Sincerely, Michael 1. Markley, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-530

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 ON THE SECOND 10-YEAR INSERVICE INSPECTION PROGRAM INTERVAL RELIEF REQUEST NO. 43 ARIZONA PUBLIC SERVICE COMPANY, ET AL.

PALO VERDE NUCLEAR GENERATING STATION, UNIT 3 DOCKET NO. STN 50-530

1.0 INTRODUCTION

By letter dated January 12, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML090280369), the Arizona Public Service Company (APS, the licensee) submitted Request for Relief No. 43 (RR-43) for the second 10-year inservice inspection (lSI) program interval for the Palo Verde Nuclear Generating Station, Unit 3 (PVNGS-3). The licensee requested relief from the requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) for examinations of certain welds and piping which the licensee has determined are impractical.

In response to a request for additional information (RAI) from the Nuclear Regulatory Commission (NRC) staff, the licensee submitted further information in its letter dated September 17, 2009 (ADAMS Accession No. ML092740372). The NRC staff has completed its review of RR-43, as documented in this safety evaluation (SE). Attachment 1 to this SE lists each individual relief request (Parts A through E) and the status of approval. The sketches, drawings, photographs, cross-sectional data, and technical descriptions provided by the licensee in the referenced letters are not restated or reproduced in this SE.

2.0 REGULATORY EVALUATION

lSI of the ASME Code Class 1, 2, and 3 components is to be performed in accordance with Section XI of the ASME Code, and applicable addenda, as required by Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g), except where specific relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). The regulation at 10 CFR 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if the licensee demonstrates that (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.

Enclosure

- 2 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 1O-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-month interval, subject to the limitations and modifications listed therein. The ASME Code of record for PVNGS-3 second 10-year interval lSI program, which ended on January 10, 2008, is the 1992 Edition, through 1992 Addenda, of Section XI of the ASME Code.

3.0 TECHNICAL EVALUATION

The information provided by the licensee in support of the request for relief from ASME Code requirements has been evaluated and the bases for disposition are documented below. For clarity, the licensee's request has been evaluated in several parts according to ASME Code,Section XI, Examination Category.

3.1 Request for Relief No. 43, Part A. ASME Code,Section XI. Examination Category B-H, Item B8.20, Integral Attachments for Vessels 3.1.1 ASME Code Requirement ASME Code,Section XI, Examination Category B-H, Item B8.20 requires essentially 100 percent surface examination of integrally welded supports on the pressurizer (PZR), as defined by ASME Code,Section XI, Figures IWB-2500-13, -14, or -15, respectively.

The examination must be performed on accessible inside diameter (10) and outside diameter (00) surfaces of the weld. If the weld is a full penetration configuration as shown in ASME Code,Section XI, IWB-2500-14, a volumetric examination may be used in lieu of the surface examination. "Essentially 100%," as clarified by ASME Code Case N-460, "Alternative Examination Coverage for Class 1 and Class 2 Welds,Section XI, Division 1," is greater than 90 percent coverage of the examination volume, or surface area, as applicable. ASME Code Case N-460 has been approved for use by the NRC in Regulatory Guide (RG) 1.147, Revision 15, "Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1" (ADAMS Accession No. ML072070419).

3.1.2 Licensee's ASME Code Relief Request In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the ASME Code required 100 percent surface examination of PZR integral support skirt Weld 5-1.

3.1.3 Licensee's Basis for Relief Request (as stated)

The Pressurizer Skirt weld (Weld #1 [5-1]) is inaccessible from the inside due to radiation, insulation, heaters, and drain lines. Only the outside surface of the

- 3 skirt weld is accessible for examination. Where the outside portion is accessible, an ultrasonic examination was also performed to augment the surface examination. The ultrasonic examination achieved 78% [ASME] Code volume coverage. Therefore, APS considers this examination to be limited. In addition, a magnetic particle [testing] (MT) surface examination was performed on 100%

of the accessible surface of the weld.

3.1.4 Licensee's Proposed Alternative Examination The licensee performed a vOlumetric examination from the outside surface to augment the limited surface examination.

3.1.5 Staff Evaluation The ASME Code requires essentially 100 percent surface examination of both 10 and 00 surfaces of PZR main support skirt Weld 5-1. However, examination on the 10 surface is restricted due to the geometry of the PZR bottom head, heater nozzle penetrations, and other appurtenances. To gain access for examination, the support skirt weld and PZR bottom head would require extensive design modifications or replacement. Imposition of this requirement would create a burden on the licensee; therefore, the ASME Code-required examination on the 10 surface is impractical.

As shown on the sketches and technical descriptions included in the licensee's submittal, surface examinations of the PZR support skirt weld have been performed to the extent practical with the licensee obtaining 100 percent examination on the 00 surface. While PZR skirt attachment Weld 5-1 is not a full penetration design, as described in ASME Code,Section XI, IWB-2500-14, the licensee conducted an augmented volumetric examination of the weld from the outside surface, and obtained additional volumetric coverage of approximately 78 percent.

This vOlumetric examination used both 45-and 50-degree shear waves applied from the skirt side of the weld. A portion of the blend radius between the PZR head and support skirt was inaccessible for examination. During the vOlumetric examinations, the 45-degree and 50-degree scans identified one indication that was seen throughout the exam area at varying amplitudes. The indication was classified as a subsurface planar flaw which was evaluated acceptable in accordance with the ASME Code. The MT examination revealed no recordable indications.

The licensee has shown that it is impractical to meet the ASME Code-required surface examination coverage on both inside and outside surfaces of the subject weld due to limited access caused by the PZR bottom head geometry, heater penetrations, and other instrument lines and insulation in this area. However, based on the 100 percent examination coverage obtained on the outside surface of the weld and the volumetric examination performed to augment the inspection, it is reasonable to conclude that, if significant service-induced degradation had occurred, evidence of it would have been detected. Furthermore, the NRC staff concludes that the examinations performed to the extent practical provide reasonable assurance of structural integrity of the subject weld.

- 4 3.2 Request for Relief No. 43, Part B, ASME Code,Section XI, Examination Category B-J, Items B9.11, Pressure Retaining Welds in Piping 3.2.1 ASME Code Requirement ASME Code,Section XI, Examination Category B-J, Item B9.11, requires essentially 100 percent volumetric and surface examinations, as defined by ASME Code,Section XI, Figures IWB-2500-8, for piping circumferential welds 4-inch nominal pipe size (NPS), and greater, in diameter. "Essentially 100%," as clarified by ASME Code Case N-460, is greater than 90 percent coverage of the examination volume, or surface area, as applicable. ASME Code Case N-460 has been approved for use by the NRC in RG 1.147, Revision 15.

3.2.2 Licensee's ASME Code Relief Request In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the ASME Code required 100 percent volumetric examination coverage of ASME Code Class 1 pipe-to-valve Weld 23-4.

3.2.3 Licensee's Basis for Relief Request (as stated)

The [ASME Code,Section XI, Table IWB-2500-1, Category B-J] piping weld was examined in accordance with the [performance demonstration initiative (PDI)]

generic procedure PDI-UT-2. No limitations to the procedural requirements were encountered. The following sketch is a typical weld profile configuration (pipe-to-fitting, pipe-to-valve, pipe-to-pump, etc.). As shown in the following sketch, these types of welds contain a taper as the connection transitions into the attached item. As a result of the slope of this taper and limited distance from the weld to the attached item, no meaningful axial scans can be performed from the tapered side of the weld.

The body of the valve on pipe-to-valve Weld 23-4 is SA 351 GR CF8M, Austenitic Steel Casting for High Temperature Service (stainless steel).

3.2.4 Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination; however, it did perform the ASME Code-required examinations to the extent practical.

3.2.5 Staff Evaluation The ASME Code requires essentially 100 percent VOlumetric and surface examination coverage for selected Examination Category B-J pressure retaining welds in piping. The volumetric examination must be applied from both sides of the weld to maximize coverage. Full ASME Code-required surface examinations were conducted on piping Weld 23-4. However, volumetric examinations are limited by the pipe-to-valve geometry of the weld, which restricts scanning to the pipe side only. To gain access for examination, the weld would require design modifications. Imposition of this requirement would create a burden on the licensee; therefore,

- 5 the ASME Code-required 100 percent vOlumetric examination coverage from both sides of the weld is impractical.

As shown on the sketches and technical descriptions included in the licensee's submittal, access for examination of Weld 23-4 is limited to the pipe side only, due to the cast material of the valve, and limited taper region caused by the valve-to-pipe and weld configuration. The ultrasonic test (UT) methods employed for this weld have been qualified through the industry's POI, which meets ASME Code,Section XI, Appendix VIII requirements. These methods have been qualified for flaws located on the near-side of welds; far-side detection of flaws is considered to be a "best effort." For this reason, the licensee has taken credit for completing only 50 percent of the ASME Code-required inspection volume on the sUbject piping weld.

However, the licensee's ultrasonic methods included 45-degree shear and 60-degree refracted longitudinal waves (L-waves), which have been shown to provide enhanced detection on the far-side of austenitic stainless steel welds (References 1 and 2). While the licensee has only taken credit for obtaining 50 percent volumetric coverage, the L-wave technique would have provided coverage well beyond the near-side of the welds. A review of the typical weld cross sectional information indicates that limited volumetric coverage on the far-side of piping Weld 23-4 has also been obtained by the licensee. No service-induced defects have been identified in these welds.

The licensee has shown that it is impractical to meet the ASME Code-required 100 percent volumetric examination coverage for the subject piping weld due to the design and ultrasonic access restrictions. Although the ASME Code-required coverage could not be obtained, the ultrasonic methods employed would have provided full volumetric coverage for the near-side of the welds and limited volumetric coverage for the weld fusion zone and base materials on the opposite side of the welds. Based on the aggregate coverage obtained for the subject welds, and considering the licensee's performance of ultrasonic techniques used to maximize this coverage, it is reasonable to conclude that if significant service-induced degradation were occurring, evidence of it would have been detected by the examinations that were performed.

The NRC staff concludes that the examinations performed to the extent practical provide reasonable assurance of structural integrity of the weld.

3.3 Request for Relief No. 43. Part C. ASME Code.Section XI. Examination Category C-C. Item C3.30, Integral Attachments for Vessels. Piping.

Pumps and Valves 3.3.1 ASME Code Requirement ASME Code,Section XI, Examination Category C-C, Item C3.30, requires 100 percent surface examination, as defined by ASME Code,Section XI, Figure IWC-2500-5, of integrally welded attachments to ASME Code Class 2 pumps. ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 15, 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 (i.e., greater than 90 percent examination coverage is obtained).

- 6 3.3.2 Licensee's ASME Code Relief Request In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the ASME Code required 100 percent surface examination of integrally welded attachments 116-1A, 116-'10, 117-1 A, and 117-1 D on high-pressure safety injection (HPSI) pumps.

3.3.3 Licensee's Basis for Relief Request (as stated)

The HPSI Pump front support lugs (116-1A, 116-1 D, 117-1A and 117-1 D) have restricted access by the structural base support material. The lugs are accessible for examination; however, the Code required examination area is limited on the bottom of the front lugs. The following drawing illustrates the location of the lugs and the photo identifies the support member limitations. A comparison photo for the rear lugs illustrates the difference in accessibility. The rear lugs were not limited and 100% coverage was obtained. The front lugs were limited at the bottom side of the lug-to-pressure boundary weld. The examination reports for the front lugs noted 78% of the required area was examined.

Therefore, APS considers this examination to be limited.

3.3.4 Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination; however, it did perform the ASME Code-required examinations to the extent practical.

3.3.5 Staff Evaluation The ASME Code requires essentially 100 percent surface examination of the length of the subject pump supports on the safety injection system. Complete examinations were restricted by the design of the support lug Welds 116-1A, 116-1 D, 117-1A, and 117-1 D on the HPSI pumps. To gain access for examination, the pump lugs would require design modifications.

Imposition of this requirement would create a burden on the licensee; therefore, the ASME Code-required 100 percent surface examinations are impractical.

As shown on the sketches, photographs, and technical descriptions included in the licensee's submittal, examinations of the subject integral attachment welds have been performed to the extent practical with the licensee obtaining surface coverage of approximately 78 percent on the pump lugs. A structural steel member adjacent to the pump causes an access limitation to the underside of Welds 116-1A, 116-1 D, 117-1A, and 117-'10 on the front support lugs for the HPSI pumps. No restrictions exist on rear support lugs, and the licensee completed the examinations on the rear support lug welds to the full ASME Code extent. No service-induced defects have been identified in Welds 117-1A and 117-1 D. For Weld 116-1A, the penetrant test (PT) examination identified one 1/8-inch round indication and one 3/16-inch round indication and for Weld 116-1 D, the PT examination identified one 1/8-inch round indication. The licensee noted in its letter dated September 17, 2009, that the size of these indications did not exceed the allowable flaw standards for the applicable supported pressure-retaining component to which the attachment is welded, and thus these welds were determined to be acceptable per the ASME Code.

- 7 The licensee has shown that it is impractical to meet the ASME Code-required surface examination coverage for the subject integrally welded attachments due to access restrictions caused by the design of the pump lugs and the presence of structural steel components. Based on the surface coverage obtained, it is reasonable to conclude that, if significant service-induced degradation had occurred in the subject welds, evidence of it would have been detected by the examinations performed. Furthermore, the NRC staff concludes that the examinations performed to the extent practical provide reasonable assurance of structural integrity of the subject weld.

3.4 Request for Relief No. 43, Part 0, ASME Code,Section XI Examination Category C-F-1, Items C5.11 and Item C5.21, Pressure Retaining Welds in Austenitic Stainless Steel or High Alloy Piping 3.4.1 ASME Code Requirement ASME Code,Section XI, Examination Category C-F-1, Items C5.11 and C5.21 require 100 percent volumetric and surface examinations, as defined by ASME Code,Section XI, Figure IWC-2500-7, of selected ASME Code Class 2 austenitic stainless steel or high alloy piping welds. ASME Code Case N-460, as an alternative approved for use by the NRC in RG 1.147, Revision 15, 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).

3.4.2 Licensee's ASME Code Relief Request In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the ASME Code required volumetric examinations of the high alloy piping welds shown in Table 3.4.1.

• ASME Code,Section XI, C*F*1 Weld 10 Weld.

Pipe Size, Thickness (Inches)

C5.11 62-24 Pipe-to-penetration 6 NPS, 0.562 T C5.11 63-4 Pipe-to-valve 6 NPS, 0.562 T C5.11 63-30 Pipe-to-penetration 6 NPS, 0.562 T C5.11 77-7 Pipe-to-flange 12 NPS, 0.375 T C5.11 77-14 Pipe-to-valve 12 NPS, 1.125 T C5.11 79-14 Pipe-to-valve 12 NPS, 1.125 T C5.11 76-7 Pipe-to-flange 12 NPS, 0.375 T C5.11 77-16 Pipe-to-valve 12 NPS, 1.125 T C5.11 84-9 Pipe-to-valve 24 NPS, 0.562 T C5.11 77-27 Pipe-to-valve 12 NPS, 1.312 T C5.11 70-121 Pipe-to-valve 16 NPS, 1.594 T C5.11 84-3 Pipe-to-penetration 24 NPS, 0.375 T

- 8 Table 3.4.1

• ASME Code,Section XI, Examination Category C..F*1

.. ASME Code Item Weld 10 Weld Configuration Pipe Size, Thickness (inches)

C5.11 84-12 Pipe-to-valve 24 NPS, 0.562 T C5.11 85-46 Pipe-to-valve 20 NPS, 0.375 T C5.21 106-1 Pipe-to-pump 4 NPS, 0.337 T C5.21 106-21 Pipe-to-valve 4 NPS, 0.438 T C5.21 107-11 Pipe-to-valve 4 NPS, 0.337 T C5.21 107-42 Pipe-to-tee 2 NPS, 0.344 T C5.21 109-21 Pipe-to-tee 4 NPS, 0.337 T C5.21 110-39 Pipe-to-penetration 3 NPS, 0.438 T C5.21 110-17 Pipe-to-valve 2 NPS, 0.344 T C5.21 110-52 Pipe-to-tee 2 NPS, 0.344 T C5.21 111-34 Pipe-to-flange 4 NPS, 0.438 T C5.21 112-45 Pipe-to-reducer 3 NPS, 0.438 T C5.21 113-21 Pipe-to-tee 2 NPS, 0.344 T C5.21 113-28 Pipe-to-valve 2 NPS, 0.344 T C5.21 115-13 Pipe-to-penetration 3 NPS, 0.438 T C5.21 118-49 Pipe-to-valve 3 NPS, 0.438 T C5.21 119-52 Pipe-to-valve 3 NPS, 0.438 T C5.21 119-53 Pipe-to-valve 2 I\\lPS, 0.344 T 3.4.3 Licensee's Basis for Relief Request (as stated)

The butt welds of [ASME Code,Section XI, Category C-F-1] with single sided access were credited to only a 50% code volume coverage based on Appendix VIII POI demonstration.

All of the C-F-1 piping welds were examined in accordance with the POI generic procedure POI-UT-2. No limitations to the procedural requirements were encountered. The Item 2 [previous ASME Code, Category B-J, Part B of this SE]

discussion illustrates a typical weld profile sketch (pipe-to-fitting, pipe-to-valve, pipe-to-pump, etc.) for these weld configurations. As shown in the sketch in Item 2, these types of welds contain a taper as the connection transitions into the attached item. As a result of the slope of this taper and limited distance from the weld to the attached item, no meaningful axial scans can be performed from the tapered side of the weld.

- 9 3.4.4 Additional Information Provided by the Licensee's Letter Dated September 17, 2009 (as stated)

Piping Welds> 3/8-inch Nominal Wall Thickness for Piping> NPS 4 inches Circumferential Welds Piping Welds> 1/5-inch Nominal Wall Thickness for Piping::: NPS 2 inches and

~ 4 inches - Circumferential Welds Weld 63-4 The PT examination revealed no recordable indications. The 45-degree SW [shear wave] UT examination revealed no recordable indications. The 60-degree refracted longitudinal wave (RL) identified one indication. This indication was classified as a geometric indication and was the result of a counterbore discontinuity which was determined to be acceptable in accordance with Appendix I - Mandatory, Supplement 11 Geometric Indications.

Weld 77-16 The PT examination revealed no recordable indications. Both the 45-degree SW and the 60-degree RL UT examinations revealed the same indication. This indication was classified as a geometric indication and was the result of a counterbore discontinuity which was determined to be acceptable in accordance with Appendix I Mandatory, Supplement 11 - Geometric Indications.

Weld 85-46 The PT examination revealed no recordable indications. A 45-degree SW examination and a supplemental 45-degree RL UT examination were performed which revealed no recordable indications. The 70-degree SW UT examination identified one indication. This indication was classified as a geometric indication and was the result of root geometry which was determined to be acceptable in accordance with Appendix I - Mandatory, Supplement 11 - Geometric Indications.

Weld 106-21 The PT examination revealed no recordable indications. The 45-degree SW UT examination revealed no recordable indications. The 70-degree SW UT examination identified one indication. This indication was classified as a geometric indication and was the result of root geometry which was determined to be acceptable in accordance with Appendix I - Mandatory, Supplement 11 - Geometric Indications.

Weld 107-42 The PT examination revealed no recordable indications. The 45-degree SW UT examination revealed no recordable indications. The 70-degree SW UT examination identified one indication. This indication was classified as a geometric indication and was the result of root geometry which was determined to be

- 10 acceptable in accordance with Appendix I - Mandatory, Supplement 11 - Geometric Indications.

Weld 112-45 The PT examination revealed no recordable indications. The 45-degree SW UT examination revealed no recordable indications. The 70-degree SW UT examination identified one indication. This indication was classified as a geometric indication and was the result of root geometry which was determined to be acceptable in accordance with Appendix I - Mandatory, Supplement 11 - Geometric Indications.

Weld 113-21 The PT examination revealed no recordable indications. The 45-degree SW UT examination revealed no recordable indications. The 70-degree SW, 60-degree SW and 60-degree RL UT examinations all identified the same single indication. This indication was classified as a geometric indication and was the result of root geometry which was determined to be acceptable in accordance with Appendix I - Mandatory, Supplement 11 Geometric Indications.

Weld 115-13 The PT examination revealed no recordable indications. The 45-degree SW UT examination revealed no recordable indications. The 70-degree SW UT examination identified one indication. This indication was classified as a geometric indication and was the result of root geometry which was determined to be acceptable in accordance with Appendix I - Mandatory, Supplement 11 - Geometric Indications.

For the remaining components listed in the ASME Code,Section XI, Examination Categories included in the January 12, 2009, submittal, no recordable indications were observed.

3.4.5 Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination; however, it did perform the ASME Code-required examinations to the extent practical.

3.4.6 Staff Evaluation The ASME Code requires essentially 100 percent volumetric and surface examination coverage for selected Examination Category C-F-1 pressure retaining welds in piping. The volumetric examination must be applied from both sides of the weld to maximize coverage. Full ASME Code-required surface examinations were conducted for all of the subject welds. However, volumetric examinations are limited by the geometry of the welds, which restricts scanning to the pipe side only. To gain access for examination, the welds would require design modifications. Imposition of this requirement would create a burden on the licensee; therefore,

- 11 the ASME Code-required 100 percent volumetric examinations from both sides of the welds are impractical.

As shown on the sketches and technical descriptions included in the licensee's submittal, access for examination of the subject welds is limited to the pipe side only due to the cast materials of the valves and the extreme tapers caused by the valve-to-pipe, pipe-to-tee, pipe-to pump, pipe-to-reducer, and pipe-to-penetration weld configurations (see Table 3.4.1 above).

The UT methods employed for these welds have been qualified through the industry's PDI, which meets ASME Code,Section XI, Appendix VIII requirements. These methods have been qualified for flaws located on the near-side of the welds; far-side detection of flaws is considered to be a "best effort." For this reason, the licensee has taken credit for completing only 50 percent of the ASME Code-required inspection volume on each of the subject piping welds.

However, depending on the piping wall thickness (see Table 3.4.1 above), the licensee's UT methods included 45-, 60- and 70-degree, shear or refracted longitudinal waves (L-waves),

which have been shown to provide enhanced detection on the far-side of austenitic stainless steel welds (References 1 and 2). While the licensee has only taken credit for obtaining 50 percent volumetric coverage, the techniques employed would have provided coverage beyond the near-side of the welds. A review of the typical weld cross-sectional information indicates that limited volumetric coverage on the far-side of the welds has been obtained by the licensee. In most cases, no service-induced defects have been identified in these.welds. In the examinations in which indications were found, they were found acceptable per the ASME Code.

The licensee has shown that it is impractical to meet the ASME Code-required 100 percent volumetric examination coverage for the subject piping welds due to their design and ultrasonic access restrictions. Although the ASME Code-required coverage could not be obtained, the UT methods employed would have provided full volumetric coverage for the near-side of the welds and limited volumetric coverage for the weld fusion zone and base materials on the opposite side of the welds. Based on the aggregate coverage obtained for the subject welds, and considering the licensee's performance of UT techniques used to maximize this coverage, it is reasonable to conclude that if significant service-induced degradation were occurring, evidence of it would have been detected by the examinations that were performed. Furthermore, the NRC staff concludes that the examinations performed to the extent practical provide reasonable assurance of structural integrity of the subject weld.

3.5 Request for Relief No. 43. Part E. ASME Code,Section XI. Examination Category C-H, Items C7.30 and C7.40, All Pressure Retaining Components 3.5.1 ASME Code Requirement ASME Code,Section XI, Examination Category C-H, Items C7.30 and C7.40, require 100 percent visual VT-2 leakage tests, as defined by ASME Code,Section XI, Figure IWC-2500-7, of selected ASME Code Class 2 austenitic stainless steel or high-alloy piping welds.

- 12 3.5.2 Licensee's ASME Code Relief Request In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the ASME Code required volumetric examinations of the high alloy piping welds 3.5.3 Licensee's Basis for Relief Request (as stated)

The three chemical and volume control system (CVCS) charging pumps each have a suction stabilizer and pulsation dampener for system stability purposes.

These components have a bladder and nitrogen system to moderate the fluid shock in the CVCS to maintain consistent operating characteristics. The nitrogen tubing lines up to and including the first isolation valve from the stabilizer and dampeners are ASME Class 2. A visual testing level II (VT-2) qualified examiner employs a "snoop" method to detect escaping gas in the form of bubbles on this tubing. This tubing has installation clips and other attachments that prevent 100% snooping of the tubing. Therefore, APS considers this examination to be limited. Note the following photograph depicts a typical installation clip and associated VT-2 limitation.

3.5.4 Licensee's Proposed Alternative Examination The licensee did not propose an alternative examination; however, it did perform the ASME Code-required examinations to the extent practical.

3.5.5 Staff Evaluation The ASME Code requires 100 percent visual VT-2 leakage tests, as defined by ASME Code,Section XI, Figure IWC-2500-7, of selected ASME Code Class 2 austenitic stainless steel or high-alloy piping welds. The licensee noted in its letter dated September 17, 2009, that the nitrogen supply lines are approximately 40 feet in length and each supply line has 30 of the clips installed. It also noted that each clip is approximately 1/2-inch wide and 30 clips which is equal to about 1.25 linear feet of nitrogen supply lines. The 1.25 linear feet represents approximately 3 percent of the 40 feet of the linear footage that was inaccessible for examination. Therefore, the licensee was able to examine 97 percent of the linear footage of the subject lines.

To examine the subject tubing, the licensee used a method called snooping, which utilizes a liquid solution that would form bubbles, if a nitrogen leak was occurring.

As shown in the photographs and technical description included in the licensee's submittal, access of the subject lines is limited due to the installation clips and other attachments, preventing the licensee from performing a 100 percent examination of the linear footage of the subject lines.

The licensee has shown that it is impractical to meet the ASME Code-required 100 percent visual examination coverage for the subject piping due to the installation clips and other attachments restrictions. Although the ASME Code-required coverage could not be obtained, the examinations methods employed would have provided full coverage for the subject tubing

- 13 linear footage. Based on the coverage obtained for the subject tubing, it is reasonable to conclude that if significant service-induced degradation were occurring, evidence of it would have been detected by the examinations that were performed. Furthermore, the NRC staff concludes that the examinations performed to the extent practical provide reasonable assurance of leak integrity of the subject tubing. All accessible portions of these lines have been examined and the licensee did not find any leakage or degrading of the subject lines.

4.0 CONCLUSION

The NRC staff has reviewed the licensee's submittal and concludes that conformance with the ASME Code examination coverage requirements is impractical for the sUbject welds and tubing listed in RR-43, Parts A through E. Furthermore, based on the volumetric, surface, and/or visual coverage obtained, it is reasonable to conclude that if significant service-induced degradation had occurred, evidence of it would have been detected by the examinations that were performed. Furthermore, the staff concludes that the examinations performed to the extent practical provide reasonable assurance of structural integrity of the subject welds and that the VT-2 visual examinations for leakage provide reasonable assurance of leak integrity of the subject tubing in RR-43, Part E.

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), and is in compliance with the ASME Code's requirements with the granting of this relief. Therefore, the NRC staff grants relief for the subject examinations of the components contained in RR-43, Parts A through E, at PVNGS-3 for the second 1O-year lSI interval.

The staff further concludes that granting RR-43, Parts A through E, 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. 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.

5.0 REFERENCES

1.

Ammirato, F.V., X. Edelmann, and S.M. Walker, Examination of Dissimilar Metal Welds in BWR Nozzle-to-Safe End Joints, 8th International Conference on NDE in the Nuclear Industry, ASM International, 1987.

STATUS OF APPROVAL RELIEF REQUEST NO. 43 PALO VERDE NUCLEAR GENERATING STATION, UNIT 3 DOCKET NO. STN 50-530 Relief Licensee Request System or Exam.

Item Volume or Area to be Required Proposed Relief Request Number Component Category No.

Examined Method Alternative Disposition RR-43 (Part A)

Integrally welded attachments B-H B8.20 100% of selected Class 1 component supports; PZR skirt weld Surface Use surface coverage achieved with augmented volumetric Granted 10 CFR 50.55a(g)(6)(i) examination RR-43 Piping welds B-J B9.11 100% of selected Class Volumetric Use volumetric Granted (Part B) 1 piping welds; pipe-to and Surface coverage(s) 10 CFR valve Weld 23-4 achieved 50.55a(g)(6)(i)

RR-43 Integrally C-C C3.30 100% of selected Class Surface Use surface Granted (Part C) welded 2 component supports; coverage(s) 10 CFR attachments HPSI pump lugs achieved 50.55a(g)(6)(i)

RR-43 Piping welds C-F-1 C5.11 100% of selected Class Volumetric Use volumetric Granted (Part D)

C5.21 2 piping welds in high and Surface coverage( s) 10 CFR alloy systems achieved 50.55a(g)(6)(i)

RR-43 (Part E)

Pressure Retaining Components C-H C7.30 C7AO 100% of all Class 2 pressure retaining components Leakage Test (VT-2 visual)

Use leakage coverage achieved Granted 10 CFR 50.55a(g)(6)(i)

Attachment

R. Edington

- 2 If you have any questions, please contact Mr. Randy Hall at (301) 415-4032 or via email at randy.hall@nrc.gov.

Sincerely, IRN Michael T. Markley, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-530

Enclosure:

Safety Evaluation cc w/encl: Distribution via Listserv DISTRIBUTION:

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