ML051640307

Third 10-Year Interval Inservice Inspection Program Plan Requests for Relief 04-ON-002 and 04-ON-003

ML051640307
Person / Time
Site:	Oconee
Issue date:	07/22/2005
From:	Marinos E NRC/NRR/DLPM/LPD2
To:	Rosalyn Jones Duke Energy Corp
Olshan L N, NRR/DLPM, 415-1419
References
TAC MC2704
Download: ML051640307 (28)

Text

July 22, 2005 Mr. Ronald A. Jones Vice President, Oconee Site Duke Energy Corporation 7800 Rochester Highway Seneca, SC 29672

SUBJECT:

THIRD 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN REQUESTS FOR RELIEF 04-ON-002 AND 04-ON-003 FOR OCONEE NUCLEAR STATION, UNIT 2 (TAC NO. MC2704)

Dear Mr. Jones:

The NRC staff, with technical assistance from its contractor, the Pacific Northwest National Laboratory, has reviewed and evaluated the information that you provided in a letter dated April 9, 2004, which proposed Requests for Relief (RRs) Nos. 04-ON-002 and 04-ON-003 for the third 10-year inservice inspection interval for Oconee Nuclear Station, Unit 2. In response to our request for additional information, you revised these RRs and provided additional information in a letter dated November 30, 2004.

We conclude that RR No. 04-ON-002 and RR No. 04-ON-03 are acceptable for Oconee, Unit 2 for the third 10-year inspection interval. As discussed in the enclosed Safety Evaluation, portions of these RRs are granted pursuant to 10 CFR 50.55a(g)(6)(i) and portions are granted pursuant to 10 CFR 50.55a(a)(3)(ii).

Sincerely,

/RA/

Evangelos C. Marinos, Chief, Section 1 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-270

Enclosure:

As stated

ML051640307 NRR-028 OFFICE PDII-1/PM PDII-1/LA BMCB/SC EMCB/SC OGC PDII-1/SC NAME LOlshan CHawes MMitchell TChan KKannler EMarinos DATE 7/21/05 7/21/05 05/ 31 /05 06 / 22 /05 07/19/05 7/22/05 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR THIRD 10-YEAR INTERVAL INSERVICE INSPECTION REQUESTS FOR RELIEF NOS. 04-ON-002 AND 04-ON-003 FOR OCONEE NUCLEAR STATION, UNIT 2 DUKE POWER COMPANY DOCKET NO. 50-270

1.0 INTRODUCTION

The Nuclear Regulatory Commission (NRC) staff, with technical assistance from its contractor, the Pacific Northwest National Laboratory (PNNL), has reviewed and evaluated the information provided by Duke Power Company (the licensee) in its letter dated April 9, 2004 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML041170047), which proposed Requests for Relief (RRs) Nos. 04-ON-002 and 04-ON-003 for the third 10-year interval inservice (ISI) interval for Oconee Nuclear Station, Unit 2 (Oconee 2). In response to a NRC request for additional information the licensee revised the RRs and provided additional information in its letter dated November 30, 2004 (ADAMS Accession No. ML043490190).

2.0 REGULATORY REQUIREMENTS ISI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) Class 1, 2, and 3 components is performed in accordance with Section XI of the ASME Code and applicable addenda as required by Title 10 of the Code of Federal Regulation (10 CFR) Section 50.55a(g), except where specific relief has been granted by the NRC pursuant to 10 CFR 50.55a(g)(6)(i). 10 CFR 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if: (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

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 pre-service examination requirements, set forth in the ASME Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," to the extent practical within the Enclosure

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 incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The ASME Code of record for the Oconee 2 third 10-year ISI inspection program, which began on December 16, 1994, is the 1989 Edition of Section XI of the ASME Code, with no addenda.

3.0 EVALUATION For the subject welds listed in RR No. 04-ON-002, for ASME Code Category B-F, B-J, C-B, C-F-1, and C-F-2 welds, and RR No. 04-ON-003, for ASME Code Category B-A and B-D welds, the NRC staff determined that the ASME Code requirements of essentially 100 percent coverage for volumetric examinations, surface examinations, or both, for the components are impractical to obtain for these welds, because of access limitations. To gain access for complete examination of these welds, design modifications would be required.

Imposition of this requirement would create a significant burden on the licensee. For these welds the ultrasonic coverage ranged from 22 percent1 through 82 percent. In addition the surface examination coverage ranged from 64 percent through 100 percent. Based on the coverage obtained, the NRC staff determined that any existing patterns of degradation would have been detected by the examinations. The examinations performed provide reasonable assurance of structural integrity of Categories B-F, B-J, C-B, C-F-1, and C-F-2 welds contained in RR No. 04-ON-002 and ASME Code Categories B-A and B-D welds contained in RR No.

04-ON-003.

For RR No. 04-ON-003, Examination Category B-J welds 2-53A-8-63 (safe end-to-pipe) and 2-53A-8-64 (core flood nozzles), the NRC staff found that the licensee performed the subject examinations in accordance with volumetric requirements of the 1989 Edition of the ASME Code,Section XI, Appendix III, instead of using performance demonstrated procedures, equipment and personnel qualified to the 1995 Edition, through 1996 Addenda, Supplements 2 and 3 of the ASME Code,Section XI, Appendix VIII as required by 10 CFR 50.55a(g)(6)(ii)(C).

The licensee was required to implement this later ASME Code Edition, and supplemental requirements, on all piping welds examined after May 22, 2000. As a result of an NRC staff request for additional information the licensee submitted an alternative to the requirements of the ASME Code. This alternative has been reviewed and accepted by the NRC staff in a Safety Evaluation dated June 20, 2005 (ML051240226).

In addition, the NRC staff had previously authorized the licensee to use an alternative ultrasonic examination performed from the inside diameter in lieu of the outside surface examination requirements prescribed in ASME Code,Section XI for nozzle safe end-to-pipe welds 2-53A-8-63 and 2-53A-8-64. NRC staff approval is documented in a Safety Evaluation dated November 15, 1995.

1. The staff found the 22 percent volumetric converge acceptable based on other scans that were performed on other portions of the subject nozzle welds. 100 percent of the examination volume was covered from the shell side of the subject welds by scanning perpendicular to the welds (axial scan) and approximately 88 percent of the ASME Code-required nozzle inside radius sections were volumetrically examined. In addition 100 percent of the surface examinations were also completed on the subject welds.

For RR No. 04-ON-003, Examination Category B-J welds 2-53A-8-63 and 2-53A-8-64, the NRC staff has determined that meeting the ASME Code requirements of essentially 100 percent volumetric examination coverage for welds 2-53A-8-63 and 2-53A-8-64 would be a significant hardship without a compensating increase in quality and safety, because of limitations that were caused by air at the top of the nozzle that prevented the transducer from making contact when scanning the surface. After two attempts, the licensee was unable to remove the air, because additional air was being reintroduced from an unknown source. The licensee then decided to perform the scans and obtain as much coverage as possible. For welds 2-53A-8-63 and 2-53A-8-64, a volumetric examination coverage of 76 percent and 71 percent, respectively, was obtained by the licensee. Based on the coverage obtained, the NRC staff has determined that any existing patterns of degradation would have been detected by the examinations. The examinations performed provide reasonable assurance of structural integrity of welds 2-53A-8-63 and 2-53A-8-64.

4.0 CONCLUSION

The Oconee 2 RR Nos. 04-ON-002 and 04-ON-003 to the ASME Code requirements have been reviewed by the NRC staff with the assistance of its contractor, PNNL. The Technical Letter Report (Attachment 2) provides PNNL's evaluation of these RRs. The NRC staff has reviewed the Technical Letter Report and adopts the evaluations and recommendations for granting or authorizing these RRs. Attachment 1 lists each relief request and the status of approval.

The NRC staff concludes that the ASME Code examination coverage requirements are impractical for the subject welds listed in RR No. 04-ON-002, for ASME Category B-F, B-J, C-B, C-F-1, and C-F-2 welds, and RR No. 04-ON-003, for ASME Category B-A and B-D welds.

Based on the coverages obtained, if significant service-induced degradation were occurring, there is reasonable assurance that evidence of it would be detected by the examinations that were performed. Therefore, for these parts of the requests, relief is granted, pursuant to 10 CFR 50.55a(g)(6)(i) for the third 10-year ISI interval at Oconee 2. 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 giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

For RR No. 04-ON-003, ASME Category B-J welds, the NRC staff has concluded that compliance with the ASME Code requirements would result in a hardship or unusual difficulty without a compensating increase in quality or safety. The volumetric coverages obtained for welds 2-53A-8-63 and 2-53A-8-64 provide reasonable assurance that evidence of significant service-induced degradation, were it occurring, would be detected by the examinations performed. Therefore, for this portion of the request the licensees proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(ii), for the third 10-year ISI interval at Oconee 2.

All other requirements of the ASME Code, Sections III and XI for which relief has not been specifically requested remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.

Attachments: As stated Principal Contributor: T. McLellan Date: July 22, 2005

TECHNICAL LETTER REPORT ON THE THIRD 10-YEAR INTERVAL INSERVICE INSPECTION REQUESTS FOR RELIEF NOS. 04-ON-002 and 04-ON-003 FOR DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNIT 2 DOCKET NUMBER: 50-270

1.0 INTRODUCTION

By letter dated April 9, 2004, the licensee, Duke Power Company, submitted Requests for Relief 04-ON-002 and 04-ON-003, seeking relief from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components. In response to an U.S. Nuclear Regulatory Commission (NRC) Request for Additional Information (RAI), the licensee revised the requests and provided further information in a letter dated November 30, 2004. These requests are for the third 10-year inservice inspection (ISI) interval at Oconee Nuclear Station, Unit 2 (Oconee 2). Pacific Northwest National Laboratory (PNNL) has evaluated the revised requests for relief and supporting information submitted by the licensee in the following sections.

2.0 REGULATORY REQUIREMENTS Inservice inspection (ISI) of the ASME Code Class 1, 2, and 3 components is to be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code (B&PV Code),

and applicable addenda, as required by Title10 of the Code of Federal Regulations (10 CFR) 50.55a(g), except where specific relief has been granted by the Nuclear Regulatory Commission (NRC) 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.

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-month interval, subject to the limitations and modifications listed therein. The ASME Code of record for the Oconee 2 third 10-year interval inservice inspection program, which began on December 16, 1994, is the 1989 Edition of Section XI of the ASME Boiler and Pressure Vessel Code, with no addenda.

Attachment 2

3.0 TECHNICAL EVALUATION

The information provided by Duke Power Company in support of the requests for relief from ASME Code requirements has been evaluated and the bases for disposition are documented below. For clarity, the request has been evaluated in several parts.

3.1 Request for Relief 04-ON-002, Examination Category B-F, Item B5.40, Pressure Retaining Dissimilar Metal Welds in Vessel Nozzles ASME Code Requirement: Examination Category B-F, Item B5.40, requires 100%

volumetric and surface examination, as defined by Figure IWB-2500-8, of Class 1 full penetration nozzle welds in the pressurizer (PZR). ASME Code Case N-460, as an alternative approved for use by the NRC staff, 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%, i.e., greater than 90% examination coverage is obtained.

Licensees ASME Code Relief Request: In accordance with 10 CFR 50.55a(g)(5)(iii),

the licensee requested relief from the 100% volumetric examination coverage requirement for PZR spray nozzle-to-safe end weld 2-PZR-WP45.

Licensees Basis for Relief Request (as stated):

The pressure spray nozzle material is SA-508 CL. 1 and the safe-end material is SB-166. The diameter of the nozzle-to-safe end weld is 4 inches and it has a wall thickness of 0.75 inches. During the ultrasonic examination of dissimilar metal weld 2-PZR-WP45, 75% coverage of the required examination volume was obtained.

Scanning limitations were caused by the taper of the nozzle which prevented scanning from both sides of the weld. The percent coverage reported represents the aggregate coverage from all scans performed on the weld. The examination volume was scanned in two circumferential and one axial direction using 45E shear wave and longitudinal wave search units. In order to scan all of the required surfaces for the inspection of this weld, the nozzle would have to be redesigned to allow scanning from both sides of the weld, which is impractical. There were no recordable indications found during the inspection of this weld.

Although 100% of the required scanning could not be achieved, the amount of coverage of the examination volume obtained for this weld provides an acceptable level of quality and integrity. In addition to the volumetric examination with limited scan, Duke Energy performed a code required surface examination on the B5.40 item and achieved 100%

coverage. The result from the surface examination was acceptable. A review of the nozzle detail drawings shows no buttering at this weld location.

Licensees Proposed Alternative Examination (as stated):

The scheduled 10-year code examination was performed on the referenced area/weld and it resulted in the noted limited coverage. No additional examinations are planned for the area/weld during the current inspection interval.

Evaluation: The ASME Code requires 100% volumetric and surface examination of Class 1 full penetration nozzle welds in the PZR. In addition, the ASME Code requires that the volumetric examination be conducted from both sides of this circumferential nozzle-to-safe end dissimilar metal weld. However, 100% volumetric examination coverage from both sides of PZR spray nozzle-to-safe end weld 2-PZR-WP45 could not be obtained due the outside surface geometry of the nozzle. For the licensee to achieve 100% volumetric coverage, the spray nozzle and weld would need to be redesigned and modified. This would place a significant burden on the licensee, thus the ASME Code-required 100% volumetric examination is impractical.

As shown on the sketches and technical descriptions provided in the request, which are not included in the report, the licensee was able to obtain approximately 75% volumetric coverage for weld 2-PZR-WP45. In fact, the licensees calculated coverage includes 100% of the ASME Code-required volume for the axial scan from the safe end side of the weld, and 100% of the ASME Code-required volume for the circumferential scans, using 45 degree shear and longitudinal waves. Only the axial scan performed from the nozzle side could not be completed due to the outside surface taper of the nozzle. In addition, the licensee completed 100% [coverage] of the ASME Code-required surface examination on weld 2-PZR-WP45 with no limitations. No indications were observed during the volumetric or surface examinations.

It is concluded that, based on nozzle-to-safe end design, the ASME Code-required volumetric examination is impractical for weld 2-PZR-WP45. Based on the volumetric coverage obtained from the safe end side of the weld, in conjunction with the full surface examination performed, if significant service-induced degradation were occurring in the subject weld, there is reasonable assurance that evidence of it would be detected by the examinations that were performed. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), it is recommended that relief be granted.

3.2 Request for Relief 04-ON-002, Examination Category B-J, Item B9.11, Pressure Retaining Welds in Piping ASME Code Requirement: Examination Category B-J, Item B9.11 requires essentially 100% volumetric and surface examination, as defined by Figure IWB-2500-8, of the length of selected Class 1 full penetration circumferential piping welds. Essentially 100%, as clarified by ASME Code Case N-460, is greater than 90% coverage of the examination volume, or surface area, as applicable.

Licensees ASME Code Relief Request: In accordance with 10 CFR 50.55a(g)(5)(iii),

the licensee requested relief from the ASME Code requirement to complete 100%

coverage of the examination volume described in Figure IWB-2500-8 for valve-to-pipe weld 2LP-189-15 on the low pressure injection system.

Licensees Basis for Relief Request (as stated):

Weld 2LP-189-15 has a diameter of 10 inches and a wall thickness of 1.0 inch. The valve and pipe material was stainless steel. During the ultrasonic examination of weld 2LP-189-5, 62.5% coverage of the required examination volume was obtained.

Scanning limitations were caused by the valve configuration which prevented scanning from both sides of the weld. The percent coverage reported represents the aggregate coverage from all scans performed on the weld. The examination volume was scanned in two circumferential directions using 45E shear waves and one axial direction using 60E shear and longitudinal waves. In order to scan all of the required surfaces for the inspection of this weld, the valve would have to be redesigned to allow scanning from both sides of the weld, which is impractical. There was a recordable indication found during the inspection of this weld. It was determined to be a geometric reflector due to root geometry.

Ultrasonic examination of areas/welds for item number B9.11 were conducted using personnel, equipment and procedures qualified in accordance with ASME Section XI, Appendix VIII Supplement 2 of the 1995 Edition with the 1996 Addenda as administered by the PDI. Although 100% [coverage] of the required scanning [volume] could not be achieved, the amount of coverage of the examination volume obtained for this weld provides an acceptable level of quality and integrity. In addition to the volumetric examination with limited scan, Duke Energy performed a [ASME Code] required surface examination on the B9.11 item and achieved 100% coverage. The result from the surface examination was acceptable.

Licensees Proposed Alternative Examination (as stated):

The scheduled 10-year code examination was performed on the referenced area/weld and it resulted in the noted limited coverage. No additional examinations are planned for the area/weld during the current inspection interval.

Evaluation: The ASME Code requires essentially 100% volumetric and surface examination of selected Class 1 full penetration piping welds. In addition, the ASME Code requires that the volumetric examination be conducted from both sides of these pressure retaining girth welds. However, the pipe-to-valve configuration of weld 2LP-189-15 on the low pressure injection system limits ultrasonic scanning to the pipe side of the weld only. For the licensee to achieve 100% volumetric coverage, the subject pipe-to-valve weld would have to be redesigned and modified. This would place a significant burden on the licensee, thus the ASME Code-required 100% volumetric examinations are impractical.

As shown on the sketches and technical descriptions provided in the request, which are not included in this report, the licensee was able to obtain approximately 62.5%

coverage of the ASME Code-required examination volume, including 100% coverage of the required volume with an axial scan from the pipe side using 60 degree shear and longitudinal waves, and 100% coverage of the circumferential scans, using 45 degree shear waves. The outside surface taper of the cast austenitic valve body prevented ultrasonic scanning from the valve side of the weld. Ultrasonic examination of weld 2-LP-189-15 was conducted using personnel, equipment and procedures qualified in

accordance with ASME Section XI, Appendix VIII, Supplement 2, 1995 Edition with the 1996 Addenda as administered through the Performance Demonstration Initiative (PDI)

Program. One ultrasonic indication was observed, but evaluated as geometrical in origin (inside diameter weld root geometry). This root geometry was confirmed with a 70 degree shear and an ID creeping wave technique. In addition, the licensee completed 100% of the ASME Code-required surface examination on Weld 2LP-189-15 with no limitations. No other indications were found during the volumetric and surface examinations.

It is concluded that, based on the pipe-to-valve design, the ASME Code-required volumetric examination is impractical for weld 2-LP-189-15. Based on the volumetric coverage obtained from the pipe side of the weld, in conjunction with the full surface examination performed, if significant service-induced degradation were occurring in the subject weld, there is reasonable assurance that evidence of it would be detected by the examinations that were performed. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), it is recommended that relief be granted.

3.3 Request for Relief 04-ON-002, Examination Category C-B, Items C2.21 and C2.22, Pressure Retaining Nozzle Welds in Vessels ASME Code Requirement: Examination Category C-B, Items C2.21 and C2.22, require 100% volumetric and surface examinations, as defined in Figure IWC-2500-4(b), of selected Class 1 nozzle-to-shell (or head) welds and nozzle inside radius sections for vessels greater than 1/2-inch in thickness. ASME Code Case N-460, as an alternative approved for use by the NRC staff, states that a reduction in examination coverage due to part geometry or interference for any Class 1 and 2 welds is acceptable provided that the reduction is less than 10%, i.e., greater than 90% examination coverage is obtained.

Licensees ASME Code Relief Request: In accordance with 10 CFR 50.55a(g)(5)(iii),

the licensee requested relief from examining 100% of the ASME Code-required weld volume for Class 2 nozzle-to-shell welds 2-SGA-WG23-1 and 2-SGA-WG23-2, and their corresponding inside radius sections. These welds are main steam outlet nozzle welds on Steam Generator A at Oconee 2.

Licensees Basis for Relief Request (as stated):

The steam generator shell material is SA-212 GR. B and the nozzle material is SA-508 CL. 1. The diameter of the nozzle-to-steam generator shell weld is 29 inches and it has a wall thickness of 6.75 inches. During the ultrasonic examination of welds 2-SGA-WG23-1 and 2-SGA-WG23-2, 100% coverage of the required examination volume could not be obtained. The examination coverage was limited to 22.22%.

Limitations were caused by the nozzle configuration. The percent coverage reported represents the aggregate coverage from all scans performed on the weld. The examination volume was scanned with 45E and 60E shear waves from one axial direction. No coverage could be achieved in the circumferential direction or with the straight beam scan because of the interference caused by the nozzle blend radius. The percentage coverage reported represents the aggregate coverage. In order to scan all of the required surfaces [volumes] for the inspection of this weld, the nozzles would have to be redesigned to allow scanning from both sides of the weld, which is

impractical. There were no recordable indications found during the inspection of these welds.

During the ultrasonic examination of the inside radius sections for 2-SGA-WG23-1 and 2-SGA-WG23-2, 100% coverage of the required examination volume was not obtained.

The examination coverage was limited to 88.11%. The percentage of coverage reported represents the aggregate coverage. The inner radius examination volume was scanned from the vessel shell side using 60E and 70E shear waves. Duke Energy Corporation had been investigating the use of computer modeling of the nozzles to develop ultrasonic techniques that would achieve 100% coverage of the examination volume. However, these techniques were not ready at the time these examinations were scheduled. Therefore, a best effort examination was performed. There were no recordable indications found during these inspections.

Licensees Proposed Alternative Examination (as stated):

The scheduled 10-year [ASME Code] code examination was performed on the referenced areas/welds and it resulted in the noted limited coverage. No additional examinations are planned for the areas/welds during the current inspection interval.

Evaluation: The ASME Code requires 100% volumetric and surface examinations of the subject Class 2 nozzle-to-shell welds, and 100% volumetric examination of the associated inner radius sections, for steam generator main steam nozzle welds 2-SGA-WG23-1 and 2-SGA-WG23-2. The ASME Code also requires that the volumetric examinations be performed from both sides of the weld using two beam paths. However, the licensee was unable to scan from the nozzle side of the welds due to the nozzles design and blend radii. For the licensee to achieve 100% volumetric coverage, the subject nozzle-to-shell welds would have to be redesigned and modified.

This would place a significant burden on the licensee, thus the ASME Code-required 100% volumetric examinations are impractical.

The licensee was only able to obtain approximately 22% volumetric coverage of these nozzle-to-shell welds. Several factors influenced this limited coverage, including:

1) the set-in design of the nozzle, resulting in the nozzle outside surface being nearly parallel to the weld cross-section; this configuration does not allow ultrasonic scans to be directed into the weld region from the nozzle side,

2) a curved outside surface weld blend transition zone between the nozzle and the shell which prevents scanning directly above the weld, and

3) the normal curvature of the domed shell tends to redirect sound from the area of interest during scanning as the ultrasonic probe is moved away from the weld.

However, the licensee stated that 100% of the examination volume was covered from the shell side of the weld, scanning perpendicular to the weld (axial scan). Also, approximately 88% of the ASME Code-required nozzle inside radius sections were volumetrically examined, and 100% of the surface examinations were completed. The steam generator main steam outlet welds are fabricated of carbon steel, so that

ultrasonic sound fields generated in the wrought base material are not significantly attenuated or redirected by the weld microstructure. Thus, examinations performed from one side only are generally adequate to detect degradation that may occur on either side of the weld.

It is concluded that, based on the design configuration of main steam outlet nozzle welds 2-SGA-WG23-1 and 2-SGA-WG23-2, the ASME Code-required volumetric examinations for these nozzle-to-shell welds and inside radius sections are impractical.

Based on the volumetric coverages obtained from the shell side of these welds, in conjunction with the full surface examinations performed, if significant service-induced degradation were occurring in the subject welds and associated inner radius sections, there is reasonable assurance that evidence of it would be detected by the examinations that were performed. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), it is recommended that relief be granted.

3.4 Request for Relief 04-ON-002, Examination Category C-F-1, Items C5.11 and C5.21, Pressure Retaining Welds in Austenitic Stainless Steel or High Alloy Piping ASME Code Requirement: Examination Category C-F-1, Items C5.11 and C5.21, require 100% volumetric and surface examination, as defined in Figure IWC-2500-7(a),

of selected Class 2 circumferential piping welds. ASME Code Case N-460, as an alternative approved for use by the NRC staff, states that a reduction in examination coverage due to part geometry or interference for any Class 1 and 2 welds is acceptable provided that the reduction is less than 10%, i.e., greater than 90% examination coverage is obtained.

Licensees ASME Code Relief Request: In accordance with 10 CFR 50.55a (g)(5)(iii),

the licensee requested relief from the ASME Code requirements to perform 100%

coverage of the examination volumes for the following ASME Class 2 stainless steel piping welds:

Weld ID Configuration Completion Percentage 2LP-150-70 Valve-to-reducer weld 56.75%

2HP-219-14 Valve-to-pipe weld 37.5%

2HP-396-5 Valve-to-pipe weld 62.5%

2HP-221-22 Valve-to-elbow weld 62.5%

Licensees Basis for Relief Request (as Stated):

Weld 2LP-150-70 has a diameter of 12 inches and a wall thickness of 1.312 inches.

The valve and reducer material was stainless steel. During the ultrasonic examination of weld 2LP-150-70, 56.75% coverage of the required examination volume was obtained. Scanning limitations were caused by the valve configuration which prevented scanning from both sides of the weld. The percent coverage reported represents the aggregate coverage from all scans performed on the weld. The examination volume

was scanned using 45E shear waves in two circumferential directions covering 59% of the volume and in one axial direction using 60E shear longitudinal waves covering 100%

of the examination volume. In order to scan all of the required surfaces [volumes] for the inspection of this weld, the valve would have to be redesigned to allow scanning from both sides of the weld, which is impractical. There were no recordable indications found during the inspection of this weld.

Weld 2HP-219-14 has a diameter of 4 inches and a wall thickness of 0.674 inches. The valve and pipe material was stainless steel. During the ultrasonic examination of weld 2HP-219-14, 37.5% coverage of the required examination volume was obtained.

Scanning limitations were caused by the valve configuration which prevented scanning from both sides of the weld. The percent coverage reported represents the aggregate coverage from all scans performed on the weld. The examination volume was scanned using 45E shear waves in two circumferential directions covering 50% of the volume and in one axial direction using 60E shear and longitudinal waves covering 100% of the examination volume. In order to scan all of the required surfaces [volumes] for the inspection of this weld, the valve would have to be redesigned to allow scanning from both sides of the weld, which is impractical. There were no recordable indications found during the inspection of this weld.

Welds 2HP-396-5 and 2HP-221-22 have a diameter of 4 inches and a wall thickness of 0.531 inches. The valve and pipe/elbow material was stainless steel. During the ultrasonic examination of welds 2HP-396-5 and 2HP-221-22, 62.5% coverage of the required examination volumes was obtained. Scanning limitations were caused by the valve-to-pipe and valve-to-elbow configurations, respectively, which prevented scanning from both sides of the weld. The percent coverage reported represents the aggregate coverage from all scans performed on the weld. The examination volume was scanned using 45E shear waves in two circumferential directions covering 50% of the volume and in one axial direction using 60E shear and longitudinal waves covering 100% of the examination volume. In order to scan all of the required surfaces [volume] for the inspection of this weld, the valves would have to be redesigned to allow scanning from both sides of the weld, which is impractical. There were no recordable indications found during the inspection of these weld.

Licensees Proposed Alternative Examination (as stated):

The scheduled 10-year [ASME Code] code examination was performed on the referenced areas/welds and it resulted in the noted limited coverage. No additional examinations are planned for the areas/welds during the current inspection interval.

Evaluation: The ASME Code requires 100% volumetric and surface examination of the subject pressure-retaining high alloy piping welds. However, complete examinations are restricted by component configurations (e.g., pipe-to-valve or elbow-to-pipe). These conditions make compliance with ASME Code-required volumetric examinations impractical to perform for these welds. To achieve greater examination coverage, substantial portions of the piping runs would need to be redesigned. Imposition of this requirement would create a significant burden on the licensee, therefore, the ASME Code-required examinations are impractical.

Drawings and descriptions included in the licensees submittal, which are not included in this report, clearly show that examinations of the subject welds have been performed to the extent practical, with the licensee obtaining aggregate volumetric examination coverages ranging from approximately 38% to 63%, and 100% of the ASME Code-required surface examinations for these welds. The volumetric examinations employed an axial scan that covered 100% of the weld metal and far-side base metal with a 60 degree refracted longitudinal beam, circumferential scans with a 45 degree shear wave, and an axial scan that covered 100% of the near-side base metal with a 60 degree shear wave.

For all the welds in this request for relief, severe limitations caused by the component configurations prevent the necessary access to achieve additional examination coverages. The limitations for these restricted examinations cannot be overcome without redesigning the subject piping welds, or adjacent components, and portions of the associated piping systems. The subject welds are part of an inspection population that includes an additional 23 Category C-F-1 welds which were examined to the full extent of ASME Code-required volumes. No problems or reportable indications have been detected during any of these examinations. The limited examinations performed by the licensee on welds 2LP-150-70, 2HP-219-14, 2HP-396-5, and 2HP-221-22, in conjunction with other Category C-F-1 weld examinations, should detect any significant patterns of degradation in the areas examined.

Based on the volumetric coverages obtained on these welds, in conjunction with the full surface examinations performed, if significant service-induced degradation were occurring in the subject welds and associated inner radius sections, there is reasonable assurance that evidence of it would be detected by the examinations that were performed. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), it is recommended that relief be granted.

3.5 Request for Relief 04-ON-002, Examination Category C-F-2, Item C5.70, Pressure Retaining Welds in Carbon or Low Alloy Steel Piping ASME Code Requirement: Examination Category C-F-2, Item C5.70 requires 100%

surface examination, as defined by Figure IWC-2500-7(b), of Class 2 socket welds (pipe to flange weld) in piping. ASME Code Case N-460, as an alternative approved for use by the NRC staff, 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%, i.e., greater than 90% examination coverage is obtained.

Licensees ASME Code Relief Request: In accordance with 10 CFR 50.55a(g)(5)(iii),

the licensee requested relief from the ASME Code requirement to complete 100%

coverage of the examination surface described in Figure IWC-2500-7(b) for the outlet flange-to-pipe weld 2-BWST-OUT-2 on the borated water storage tank (BWST).

Licensees Basis for Relief Request (as stated):

The diameter of the pipe to flange weld is 14 inches and it has a wall thickness of 0.375 inches. The material was carbon steel. During MT [Magnetic Particle Testing]

examination of weld 2BWST-OUT-2, 100% coverage of the required examination

surface could not be obtained. The examination coverage was limited to 63.66%.

Limitations were caused because the pipe has minimum clearance from a steel support member; thus, access for the inspection of 100% of the weld is not possible. The percentage of coverage reported represents the aggregate coverage. There were no recordable indications found during the inspection of this weld. In order to achieve more coverage, the pipe would have to be relocated to allow full access to MT or PT [Liquid Penetrant] 100% of the weld, which is impractical.

Licensees Response to the Request for Additional Information (as stated):

BWST stands for Borated Water Storage Tank and the material associated with the tank is A-283 GR.C carbon steel, the piping material is A-106 GR B carbon steel and the flange material is SA-181 carbon steel. There are several factors that contribute to the surface area limitation. The first factor is that the BWST is sitting on a concrete base of which the bottom of the piping associated with the limited weld is located at approximately 5 inches from the concrete base surface. The second factor is that the backside of the flange surface is located only 2.75 inches from the BWST wall surface and the distance from the outside diameter of the flange to the concrete base surface is only 2.187 inches. The third factor is that there are 39 anchor bolt brackets evenly spaced around the bottom of the BWST that have a siding plate attached to the anchor brackets. One of the anchor brackets is the support steel member that has minimum clearance from the pipe which was noted in Paragraph I of Relief Request 04-ON-002.

It is this very confined space that caused the liquid penetrant examination to be limited.

A liquid penetrant examination was the method of surface examination performed on this weld. Paragraph I in Relief Request 04-ON-002 was corrected to show that a Liquid Penetrant exam was performed. There were no other C5.07 items examined during this inspection interval.

Licensees Proposed Alternative Examination (as stated):

The scheduled 10-year code [ASME Code] examination was performed on the referenced area/weld and it resulted in the noted limited coverage. No additional examinations are planned for the area/weld during the current inspection interval.

Evaluation: The ASME Code requires 100% surface examination of certain Class 2 socket welds in piping systems. However, due to the design and proximity of structural components near the outlet flange-to-pipe weld 2-BWST-OUT-2, the surface is not accessible for complete examination. For the licensee to achieve 100% surface examination coverage, the subject flange-to-pipe socket weld, and nearby structural elements, would have to be redesigned and modified. This would place a significant burden on the licensee, thus the ASME Code-required 100% volumetric examinations are impractical.

Weld 2-BWST-OUT-2 is located on the outlet flange near the bottom of the BWST.

Very limited spaces exist between the weld surface and the concrete support base pad (approximately 5 inches), as well as, the BWST outside surface (approximately 2.75 inches). In addition, BWST anchor bolt brackets and supporting steel structures further limit access to apply the surface examination. However, the licensee was able to obtain approximately 64% coverage during the ASME Code-required surface examination,

given the extremely limited accessibility. There were no indications detected during this examination. The surface examination coverage obtained should detect any significant patterns of degradation in the areas examined.

Based on the surface coverage obtained on this socket weld, if significant service-induced degradation were occurring, there is reasonable assurance that evidence of it would be detected by the examinations that were performed. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), it is recommended that relief be granted.

3.6 Request for Relief 04-ON-003, Examination Category B-A, Items B1.11 and B1.21, Pressure Retaining Welds in Reactor Vessel ASME Code Requirement: Examination Category B-A, Items B1.11 and B1.21 require essentially 100% volumetric examination, as defined by Figures IWB-2500-1 and -3, of the length of Class 1 full penetration circumferential shell and head welds in the reactor pressure vessel (RPV). ASME Code Case N-460, as an alternative approved for use by the NRC staff, 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%, i.e., greater than 90% examination coverage is obtained.

Licensees ASME Code Relief Request: In accordance with 10 CFR 50.55a(g)(5)(iii),

the licensee requested relief from the ASME Code requirement to complete essentially 100% coverage of the examination volumes described in IWB-2500-1 and -3 for RPV lower shell-to-lower head ring weld 2-RPV-WR-34 and lower head cap-to-lower head ring weld 2-RPV-WR35.

Licensees Basis for Relief Request (as stated):

During the ultrasonic examination of welds 2-RPV-WR34 and 2-RPV-WR35, 100%

coverage of the required examination volume could not be obtained. The examination coverage was limited to 36% and 42%, respectively. Limitations were caused by the core guide lugs & flow stabilizers for WR34 [2-RPV-WR34] and incore nozzles & flow stabilizers for WR35 [2-RPV-WR35] that restrict the scanning surface as shown on the Attachment A, B, and C drawings. The percent coverage reported represents the aggregate coverage from all scans. Some areas received no coverage at all while some areas were completely covered from four directions. 13.3% of the near surface (inner 15% of wall thickness) volume of the weld and base material was covered in four scan directions using a 70E beam angle from one axial and circumferential direction. Only 10.1% of the near surface volume of the weld and base material received no coverage.

There were no recordable indications found in the areas that were examined for either of these two welds. In order to achieve more coverage the core guide lugs, incore nozzles and flow stabilizers would have to be moved to allow greater access for scanning, which is impractical.

Ultrasonic examination of welds 2-RPV-WR34 and 2-RPV-WR35 was conducted using personnel, equipment and procedures qualified in accordance with ASME Section XI, Appendix VIII, Supplements 4 and 6, 1995 Edition with the 1996 Addenda as administered through the PDI Program. Although limited scanning prevented 100%

coverage of the examination volume, the amount of coverage obtained for these

examinations along with the additional volumetric and visual examinations (listed in the next paragraph) provides an acceptable level of quality and integrity.

In addition to the Category B-A welds that relief is being sought for, there were 4 circumferential Category B-A welds that were inspected, and all obtained greater than 90% coverage and there were no reportable indications found during the inspections.

Visual examinations were also performed as part of the reactor vessel inspections (Item numbers B13.10 and B13.50) and were found to be without any reportable indications.

Licensees Proposed Alternative Examination (as stated):

The scheduled 10-year code [ASME Code] examination was performed on the referenced areas/welds and it resulted in the noted limited scanning and coverage of the required ultrasonic volume. No additional examinations are planned for the areas/welds during the current inspection interval.

Licensees Response to the Request for Additional Information (as stated):

The reference to 13.3% of the near surface volume is incorrect. It should read as follows:

The near surface volume of the weld and base material (inner 15% of wall thickness) received the following coverage:

13.4% of the weld length covered in four scan directions 38.3% of the weld length covered in one axial and one circumferential direction 48.3% of the weld length received no coverage All near surface volume scans were conducted using a 70° beam angle.

The outer 85% of the weld and base material received the following coverage:

13.4% of the weld length covered in four scan directions 38.3% of the weld length covered in one axial and one circumferential direction 48.3% of the weld length received no coverage The outer 85% volume scans were conducted using 45° and 60° beam angles Paragraph A of Relief Request 04-ON-003 was revised to incorporate the above information.

Evaluation: The ASME Code requires essentially 100% volumetric examination of Class 1 full penetration RPV circumferential shell and head welds. However, 100%

coverage for RPV lower shell-to-head ring weld 2-RPV-WR34 and lower head ring-to-cap weld 2-RPV-WR35 is not possible. The vessel core guide lugs and flow stabilizers limit the scanning coverage for weld 2-RPV-WR34, and incore nozzles and flow stabilizers limit scanning coverage for weld 2-RPV-WR35. For the licensee to achieve 100% volumetric coverage, the RPV would need to be redesigned and modified. This would place a significant burden on the licensee, thus the ASME Code-required 100% volumetric examinations are impractical.

As shown on the sketches and technical descriptions provided by the licensee, which are not included in this report, an aggregate coverage of approximately 36% and 42% of the required examination volumes were obtained for welds 2-RPV-WR34 and 2-RPV-WR35, respectively. This aggregate includes examination of a portion of each weld with a 70 degree beam angle in order to detect flaws in the inner 15% of the weld volume, and with 45 and 60 degree angles for the outer 85% of the weld volume. The ultrasonic examination of welds 2-RPV-WR34 and 2-RPV-WR35 were conducted using personnel, equipment and procedures qualified in accordance with ASME Section XI, Appendix VIII, 1995 Edition with the 1996 Addenda as administered through the EPRI PDI. Ultrasonic systems qualified through the EPRI PDI program have shown high (approximately 90%) probability of detection levels. This has resulted in an increased reliability of inspections for weld configurations within the scope of PDI (Performance Demonstration - 25 Years of Progress; L. Beckner, Electric Power Research Institute, 3nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, November 14-16, 2001, Seville Spain).

In addition, other pressure-retaining shell welds in the RPV were examined to the full extent of ASME Code requirements. No service-induced flaws were detected during any of these examinations. It is concluded that, due to the design of the RPV, it is impractical for the licensee to meet the ASME Code-required 100% volumetric examination coverage on welds 2-RPV-WR34 and 2-RPV-WR35. Based on the limited examinations that have been completed on these welds, in conjunction with full volumetric examinations on other RPV shell welds, if significant service-induced degradation were occurring, there is reasonable assurance that evidence of it would be detected by the examinations that were performed. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), it is recommended that relief be granted.

3.7 Request for Relief 04-ON-003, Examination Category B-D, Items B3.90 and B3.100, Full Penetration Welded Nozzles in Vessels ASME Code Requirement: Examination Category B-D, Items B3.90 and B3.100 require 100% volumetric examination, as defined by Figure IWB-2500-7(a), of Class 1 full penetration nozzle-to-vessel welds and associated inside radius sections. ASME Code Case N-460, as an alternative approved for use by the NRC staff, 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%, i.e., greater than 90%

examination coverage is obtained.

Licensees ASME Code Relief Request: In accordance with 10 CFR 50.55a(g)(5)(iii),

the licensee requested relief from the ASME Code requirement to complete 100%

coverage of the examination volumes described in IWB-2500-7(a) for RPV outlet nozzle-to-shell welds 2-RPV-WR13 and 2-RPV-WR13A, and core flood nozzle-to-shell welds 2-RPV-WR54 and 2-RPV-WR54A, and associated inside radius sections on welds 2-RPV-WR54 and 2-RPV-WR54A.

Licensees Basis for Relief Request (as stated):

During the ultrasonic examination of welds 2-RPV-WR13 and 2-RPV-WR13A, 100%

coverage of the required examination volume could not be obtained. The examination coverage was limited to 82% [of the required volumes]. Limitations were caused by the outlet nozzle boss that restricts the scanning surface both from the nozzle ID and the vessel ID. The percent of coverage reported represents the aggregate coverage from all scans. The weld and adjacent base material received 100% coverage from the nozzle bore with 15E and 45E beam angles. Scans from the vessel shell side resulted in 42% coverage of the weld and base material with a 45E beam angle of the outer 85% of the vessel wall and coverage of the inner 15% with a 70E beam angle. There were no recordable indications found in the areas that were examined for weld 2-RPV-WR13.

There were 21 recordable indications found during examination of weld 2-RPV-WR13A.

All of the indications were detected from the nozzle bore and were determined to be acceptable, sub-surface flaws. In order to achieve more coverage, the outlet nozzles boss would have to be moved to allow greater access for scanning, which is impractical.

During the ultrasonic examination of welds 2-RPV-WR54 and 2-RPV-54A, 100%

coverage of the required examination volume could not be obtained. The examination coverage was limited to 81% of the required volumes. The core flood nozzles of a B&W

[Babcock and Wilcox design] 177 plant have several obstructions which limit ultrasonic examination coverage. In order of significance these are:

1. The flow restrictor which is welded to the inner bore of the nozzle.

2. The inlet nozzles located 30E on either side of each core flood nozzle.

3. The taper above the core flood nozzles associated with the core support ledge.

The percentage of exam volume coverage reported represents the aggregate coverage as follows:

• Weld and adjacent base material = 81% scanned parallel to the weld centerline in two directions and perpendicular to the weld centerline from one direction.

• Inner 15% from the vessel ID = 97%, in four orthogonal directions.

There were no recordable indications found in the area that was examined for weld 2-RPV-WR54. There was one recordable indication found during examination of weld 2-RPV-WR54A. This indication was detected from the vessel ID and was determined to be an acceptable, sub-surface flaw. In order to achieve more coverage, the inlet nozzles would have to be moved and the taper on the flange would have to be redesigned to allow greater access for scanning which is impractical. In addition, because of the proximity of the flow restrictors no scanning was performed from the nozzle ID. (0% examination coverage). In order to achieve more coverage, the flow restrictor would have to be moved to allow access for scanning, which is impractical.

During the ultrasonic examination of inside radius sections [of welds] 2-RPV-WR54 and 2-RPV-54A, 100% coverage of the required examination volume could not be obtained.

The examination coverage was limited to 52% [of the required volumes]. Limitations were caused by the flow restrictor that prevents scanning from the nozzle bore surface.

The percentage of coverage reported represents the aggregate coverage from all scans. There were no recordable indications found in the areas that were examined for either of these inside radius sections. In order to achieve more coverage, the flow

restrictor would have to be moved to allow greater access for scanning, which is impractical.

Ultrasonic examination of RPV outlet and core flood nozzle welds 2-RPV-WR13, 2-RPV-WR13A, 2-RPV-WR54 and 2-RPV-WR54A were conducted using personnel, equipment and procedures qualified in accordance with ASME Section XI, Appendix I, 1989 Edition with no Addenda.

Licensees Proposed Alternative Examination (as stated):

The scheduled 10-year code [ASME Code] examination was performed on the referenced areas/welds and it resulted in the noted limited scanning and coverage of the required ultrasonic volume. No additional examinations are planned for the areas/welds during the current inspection interval.

Licensees Response to the Request for Additional Information (as stated):

The [Item] B03.100 (inner radius sections) examinations for [welds] 2-RPV-WR13 and 2-RPV-WR13A were performed. The results of the examinations were acceptable and 98% coverage was achieved for each of the items. The flow restrictor is welded to the inner bore of the nozzle. Since the flow restrictor is permanently attached to the inside of the nozzle it prevents scanning from the nozzle bore area. The inlet nozzles are located 30° on either side of each core flood nozzle. The inlet nozzles limit scanning between 90° to 150° and between 225° to 270°. The shell taper above the core flood nozzles is associated with the core support ledge. The core support ledge limits scanning to a maximum scan distance of 31.44 inches from the nozzle center line between 315° and 45°.

The following information is offered to support the determination that additional coverage could not reasonably be increased by examination from the outside nozzle surface:

Approximately 40 man-hours would be required to prepare each weld for examination.

The preparation would involve removing the refueling canal seal plate, shielding bricks, shielding supports and insulation. The radiation dose rate in the nozzle area is estimated to be 0.51 R/hr. An alternative approach is to enter from the bottom of the RPV and build a scaffold approximately 30 feet high to reach the nozzles. This effort would require approximately 80 man-hours, 40 in a 0.51 R/hr radiation field and another 40 in a 1-2 R/hr field at the bottom of the RPV. The total anticipated exposure would be 80-140 man-rem. Shielding is considered impractical in this area. The dose information noted in this paragraph was the reason Relief Request ONS-001 was submitted to perform UT from the ID surface in lieu of performing the OD [Outside Diameter] surface examinations for the core flood nozzle to safe end welds. Relief Request ONS-001 was approved by SER dated 11-15-1995 (TAC # M88484, M88485, and M88486). The same problem with dose would be incurred if examinations were to be performed from the OD surface for welds 2-RPV-WR54 and 2-RPV-WR54A.

Evaluation: The ASME Code requires 100% volumetric examination of Class 1 full penetration nozzle-to-vessel welds and inner radius sections for all RPV nozzles.

However, the specific designs of the reactor outlet and core flood nozzles limits access for examination of these welds so that 100% of the required coverage cannot be obtained. For the licensee to achieve 100% volumetric coverage, the subject nozzles would have to be redesigned and modified. This would place a significant burden on the licensee, thus the ASME Code-required 100% volumetric examinations are impractical.

As shown on the sketches and technical descriptions provided by the licensee, which are not included in this report, the examinations of primary outlet nozzle welds 2-RPV-WR13 and 2-RPV-WR13A (90 and 270 degrees, respectively) are limited by the nozzle boss that restricts the scanning surface. The examinations of welds 2-RPV-WR54 and 2-RPV-WR54A (0 and 180 degrees, respectively) are limited by the flange taper and proximity of the inlet nozzles, which restrict scanning. However, the licensee was able to obtain approximately 80% of the ASME Code-required examination volumes for these welds.

The ASME Code-required inspection volume of the inside radius sections of nozzle-to-vessel welds 2-RPV-WR54 and 2-RPV-WR54A could not be examined due to the proximity of flow restrictors inside the nozzle that do not permit scanning from the inner surface. The licensee was able to examine 52% of the required examination volume for these inside radius sections. The inner radius sections for welds 2-RPV-WR13 and 2-RPV-WR13A were fully examined in accordance with ASME Code requirements.

The examinations performed by the licensee did not detect any unacceptable indications and there is no history of failures for these nozzle-to-vessel welds. While the licensee cannot meet the ASME Code-required 100% volumetric examination coverage for these nozzle-to-vessel welds and associated inner radius sections, if significant service-induced degradation were occurring, there is reasonable assurance that evidence of it would be detected by the examinations that were performed. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), it is recommended that relief be granted.

3.8 Request for Relief 04-ON-003, Examination Category B-J, Item B9.11, Pressure Retaining Welds in Piping ASME Code Requirement: Examination Category B-J, Item B9.11, requires essentially 100% surface and volumetric examination, as defined by Figure IWB-2500-8, of the length of selected Class 1 of circumferential piping welds greater than NPS 4-inches in diameter. ASME Code Case N-460, as an alternative approved for use by the NRC staff, 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%, i.e., greater than 90% examination coverage is obtained.

Note: During this review it was discovered that the licensee performed the subject examinations in accordance with volumetric requirements of the 1989 Edition of the ASME Code,Section XI, Appendix III, instead of using performance demonstrated procedures, equipment and personnel qualified to the 1995 Edition, through 1996 Addenda, Supplements 2 and 3 of the ASME Code,Section XI, Appendix VIII as required by 10 CFR 50.55a(g)(6)(ii)(C). The licensee was required to implement this later ASME Code Edition, and supplemental requirements, on all piping welds examined

after May 22, 2000. As a result of an NRC request for additional information the licensee submitted an alternative to the requirements of the ASME Code. This alternative has been reviewed and accepted by the NRC in a Safety Evaluation dated June 20, 2005 (ML051240226).

Licensees ASME Code Relief Request: In accordance with 10 CFR 50.55a(g)(5)(iii),

the licensee requested relief from the ASME Code requirement to complete essentially 100% coverage of the examination volumes described in IWB-2500-8 for safe end-to-pipe welds 2-53A-8-63 and 2-53A-8-64 on the core flood nozzles.

Licensees Basis for Relief (as stated):

During the ultrasonic examination of welds 2-53A-8-63 and 2-53A-8-64, 100% coverage of the required examination volume could not be obtained. The examination coverage was limited to 76% and 71%, respectively. Limitations were caused by air at the top of the nozzle that prevented the transducer from making contact for scanning the surface.

The reactor vessel inspection services vendor made two attempts to evacuate the air with equipment made for the purpose but additional air was reintroduced from an unknown source. After the second attempt was unsuccessful and the source for the air could not be determined, a decision was made to perform the scan and obtain as much coverage as possible (the percentage shown above). The vendor noted that similar problems with eliminating trapped air have been experienced on other RPVs with small diameter piping.

Alternatively, it is impractical to perform this exam from the outside nozzle surface due to the excessive personnel radiation exposure. Approximately 40 man-hours would be required to prepare each safe-end to pipe weld for examination from the outside surface. The preparation involves removing the refueling canal seal plate, shielding bricks, and shielding supports in the nozzle area and insulation. The radiation levels in this area are expected to be 0.51 R/hr. An alternative path would be to enter from the bottom of the RPV and build scaffolding approximately 30 feet high to reach the core flood nozzles. This activity would require approximately 80 man-hours; 40 man-hours in a 0.51R/hr radiation field and 40 man-hours in a 1-2 R/hr radiation field. Total estimated exposure would be 80-140 man-rem. Shielding in this area is impractical. Any remote inspection would require the same preparatory work.

The percent of coverage reported represents the aggregate coverage. There were no recordable indications found in the volumes that were examined for either of these two welds. In order to achieve more coverage, the air would have to be eliminated which proved to be impractical during the subject inspection.

Ultrasonic examination of areas/welds 2-53A-8-63 and 2-53A-8-64 were conducted using personnel, equipment and procedures qualified in accordance with ASME Section XI, Appendix III, 1989 Edition with no Addenda. Inspection of Item B9.11 welds from the outside diameter is not a viable alternate due to the dose that would be received to prepare and perform the inspections. Relief Requests ONS-001 and ONS-002 were written to perform UT [ultrasonic examination] from the ID surface in lieu of a surface exam from the OD surface of all RPV nozzle to pipe welds due to the radiation exposure that is involved with performing inspections from the OD surface. Requests for Relief

ONS-001 and ONS-002 were granted in an SE dated November 15, 1995. Although limited scanning prevented 100% coverage of the examination volume, the amount of coverage obtained for these examinations provides an acceptable level of quality and integrity.

Licensees Proposed Alternative Examination (as stated):

The scheduled 10-year code [ASME Code] examination was performed on the referenced areas/welds and it resulted in the noted limited scanning and coverage of the required ultrasonic volume. No additional examinations are planned for the areas/welds during the current inspection interval.

Licensees Response to the Request for Additional Information (as stated):

When the PDI proposed an alternative implementation schedule, the examinations of Category B-J welds performed from the inside surface were not considered during the public comment period. Qualification specimens for the B-J welds past the RPV nozzle were not available at the time the examinations were scheduled for Oconee 2.

Specimens that existed prior to November 2002 were not suitable for an inside qualification. Duke Power has prepared Request for Relief 04-ON-014 to explain our use of Appendix III, 1989 Edition as an alternative to [Section XI], Appendix VIII, Supplement 2, 1995 Edition with 1996 addenda for qualifying personnel, equipment and procedures for the examination of these welds.

Evaluation: The ASME Code requires essentially 100% volumetric and surface examinations of RPV nozzle safe end-to-pipe welds. The NRC previously authorized the licensee to use an alternative ultrasonic examination performed from the inside diameter in lieu of the outside surface examination requirements prescribed in Section XI for nozzle safe end-to-pipe welds. NRC approval is documented in a Safety Evaluation Report dated November 15, 1995. As an alternative, the licensee has proposed to use the reduced volumetric coverage that was obtained during these examinations in lieu of the ASME Code-required volumetric and surface examinations.

During the ultrasonic examination of core flood nozzle safe end-to-pipe welds 2-53A-8-63 and 2-53A-8-64, the licensee discovered that air had become entrapped at the top of piping at the subject welds. The trapped air resulted in limited examinations near the top of the nozzles due to an inability to couple the ultrasonic transducers to the inside surface. The licensee made two attempts to evacuate the air but was unsuccessful because air was reintroduced and the licensee could not determine the source of the air. Similar problems with eliminating trapped air in small diameter piping have occurred in other RPV examinations. An alternative for achieving more examination coverage would have been for the licensee to manually examine the nozzle from the outside surface. Accessing the subject nozzle welds from the outside diameter is physically possible, however, the licensee stated that such an examination would result in approximately 80-140 man-rem in exposure resulting from supporting activities associated with this type of examination. The activities include preparation of the nozzle safe end-to-pipe welds for examination, removing the refueling canal seal plate, providing shielding, removing insulation and conducting the examination.

The licensee completed approximately 71% to 76% of the required volumetric examinations for the subject welds. The licensee did not record any indications in the portions of the nozzle welds that were examined. In addition, 100% of the ASME Code-required volumetric examinations were obtained for other Category B-J piping welds in the reactor coolant system. Exposing inspection personnel to 80 to 140 man-rem of radiation [exposure] for an increase of less than 20% in examination volume coverage is not warranted and would result in a hardship without a compensating increase in quality or safety.

The limitations (trapped air) as described above prevented the licensee from achieving 100% of the alternative volumetric examination from the inside diameter of the pipe.

However, the licensee completed approximately 71% to 76% of the alternative volumetric examination from the inside surface for the subject welds. Any existing patterns of degradation that may occur on these welds should be detected by the limited examinations performed by the licensee. The licensee could meet the ASME Code requirements by examining these welds from the outside surface, however, as shown in the discussion above, this would result in a significant hardship.

Based on the examination limitations caused by the trapped air in core flood nozzle safe end-to-pipe welds 2-53A-8-63 and 2-53A-8-64, and considering the levels of volumetric coverage obtained, requiring the licensee to access the outside surface of the component to make relatively small increases (less than 20%) in coverage would result in a hardship with no compensating increase in quality or safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(ii), it is recommended that the licensee's alternative be authorized.

The licensee should make every effort to eliminate entrapped air during the next inspection of these components.

4.0 CONCLUSION

S PNNL staff have reviewed the licensee's submittal and conclude that the ASME Code examination coverage requirements are impractical for the subject welds listed in Request for Relief 04-ON-002, for ASME Category B-F, B-J, C-B, C-F-1, and C-F-2 welds, and Request for Relief No. 04-ON-003, for ASME Category B-A and B-D welds. Based on the coverages obtained, if significant service-induced degradation were occurring, there is reasonable assurance that evidence of it would be detected by the examinations that were performed.

Therefore, for these parts of the requests, it is recommended that relief be granted, pursuant to 10 CFR 50.55a(g)(6)(i), for the third inspection interval at Oconee 2.

For Request for Relief 04-ON-003, for ASME Category B-J welds, it has been shown that compliance with the ASME Code requirements would result in a hardship or unusual difficulty with no compensating increase in quality or safety. The volumetric coverages obtained for the subject welds in the licensees alternative provide reasonable assurance that evidence of significant service-induced degradation, were it occurring, would be detected by the examinations being performed. Therefore, for this portion of the request, it is recommended that the alternative be authorized, pursuant to 10 CFR 50.55a(a)(3)(ii), for the third inspection interval at Oconee 2.

All other requirements of the ASME Code, Sections III and XI for which relief has not been specifically requested remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.

OCONEE NUCLEAR POWER STATION, UNIT 2 Page 1 of 1 Third 10-Year ISI Interval TABLE 1

SUMMARY

OF RELIEF REQUESTS Relief PNNL Request TLR System or Exam. Required Licensee Proposed Relief Request Number RR Sec. Component Category Item No. Volume or Area to be Examined Method Alternative Disposition 04-ON-002 3.1 PZR Spray B-F B5.40 100% of dissimilar metal Weld 2-PZR- Volumetric Use achieved volumetric Granted Nozzle WP45 in PZR spray nozzle and Surface coverage 10CFR50.55a(g)(6)(i) 04-ON-002 3.2 Class 1 B-J B9.11 100% of circumferential Weld 2LP- Volumetric Use achieved volumetric Granted Piping Welds 189-15 in the low pressure safety and Surface coverage 10CFR50.55a(g)(6)(i) injection system 04-ON-002 3.3 SG Nozzle- C-B C2.21 100% of main steam outlet nozzle-to- Volumetric Use achieved volumetric Granted to-Shell C2.22 shell Welds 2-SGA-WG23-1 and -2 and Surface coverage 10CFR50.55a(g)(6)(i)

Welds 04-ON-002 3.4 Class 2 C-F-1 C5.11 100% of circumferential piping Welds Volumetric Use achieved volumetric Granted Piping Welds C5.21 2LP-150-70, 2HP-219-14, 2HP-396-5 and Surface coverage 10CFR50.55a(g)(6)(i) and 2HP-221-22 04-ON-002 3.5 Class 2 C-F-2 C5.70 100% of socket weld 2-BWST-OUT-2 Surface Use achieved surface Granted Piping Welds on the borated water storage tank coverage 10CFR50.55a(g)(6)(i) outlet nozzle 04-ON-003 3.6 RPV Shell B-A B1.11 100% of RPV bottom shell-to-head Volumetric Use achieved volumetric Granted and Head B1.21 Welds 2-RPV-WR34 and 2-RPV- coverage 10CFR50.55a(g)(6)(i)

Welds WR35 04-ON-003 3.7 RPV Nozzle B-D B3.90 100% of nozzle-to-shell welds 2-RPV- Volumetric Use achieved volumetric Granted Welds B3.100 WR13, 2-RPV-WR13A, 2-RPV-WR54, coverage 10CFR50.55a(g)(6)(i) and 2-RPV-WR54A 04-ON-003 3.8 Class 1 B-J B9.11 100% of safe end-to-pipe Welds 2- Volumetric Use achieved volumetric Authorized Piping Welds 53A-8-63 and 2-53A-8-64 and surface and surface coverage 10CFR50.55a(a)(3)(ii)

Attachment 1

Oconee Nuclear Station, Units 1, 2, and 3 cc:

Ms. Lisa F. Vaughn Ms. Karen E. Long Duke Energy Corporation Assistant Attorney General Mail Code - PB05E NC Department of Justice 422 S. Church St. P.O. Box 629 P.O. Box 1244 Raleigh, NC 27602 Charlotte, NC 28201-1244 Mr. R. L. Gill, Jr.

Ms. Anne W. Cottingham, Esq. Manager - Nuclear Regulatory Winston and Strawn LLP Issues and Industry Affairs 1700 L St, NW Duke Energy Corporation Washington, DC 20006 526 S. Church St.

Mail Stop EC05P Manager, LIS Charlotte, NC 28202 NUS Corporation 2650 McCormick Dr., 3rd Floor Mr. Richard M. Fry, Director Clearwater, FL 34619-1035 Division of Radiation Protection NC Dept of Environment, Health, & Natural Senior Resident Inspector Resources U.S. Nuclear Regulatory Commission 3825 Barrett Dr.

7812B Rochester Highway Raleigh, NC 27609-7721 Seneca, SC 29672 Mr. Peter R. Harden, IV Mr. Henry Porter, Director VP-Customer Relations and Sales Division of Radioactive Waste Management Westinghouse Electric Company Bureau of Land and Waste Management 6000 Fairview Road Dept. of Health and Env. Control 12th Floor 2600 Bull St. Charlotte, NC 28210 Columbia, SC 29201-1708 Mr. Henry Barron Mr. Michael A. Schoppman Group Vice President, Nuclear Generation Framatome ANP and Chief Nuclear Officer 1911 North Ft. Myer Dr. P.O. Box 1006-EC07H Suite 705 Charlotte, NC 28201-1006 Rosslyn, VA 22209 Mr. B. G. Davenport Regulatory Compliance Manager Oconee Nuclear Site Duke Energy Corporation ON03RC 7800 Rochester Highway Seneca, SC 29672