PLA-6159, Proposed Relief Request No. 3RR-14 to Third 10-Year In-Service Inspection Program
| ML071010140 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 03/30/2007 |
| From: | Mckinney B Susquehanna |
| To: | Document Control Desk, NRC/NRR/ADRO |
| References | |
| PLA-6159 | |
| Download: ML071010140 (11) | |
Text
Britt T. McKinney PPL Susquehanna, LLC Vice President-Nuclear Site Operations 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3149 Fax 570.542.1504 btmckinney@pplweb.com PP~I %!*.
'T MAR 3 0 2007 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station OP 1-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION PROPOSED RELIEF REQUEST NO. 3RR-14 TO THE THIRD 10-YEAR IN-SERVICE INSPECTION PROGRAM FOR SUSQUEHANNA SES UNITS 1 AND 2 Docket Nos. 50-387 PLA-6159 and 50-388 This letter requests NRC approval of PPL Susquehanna, LLC (PPL) Relief Request No. 3RR-14, in support of the Third 10-Year In-service Inspection interval for Susquehanna SES Units 1 and 2.
This relief request is submitted in accordance with 10 CFR 50.55a(a)(3)(i) and applies to the use of an alternate program for the inspection of the RPV shell-to-flange weld and head-to-flange weld. The alternative program will be implemented through the Performance Demonstration Initiative (PDI) program.
This relief request is similar to one approved for the Edwin I. Hatch Nuclear Plant on January 3, 2006 (Accession Number ML053470091). Approval is requested by January 1, 2008.
Should you have any questions, please contact Mr. C. T. Coddington at (610) 774-4019.
B. T. McKinney Enclosure - Relief Request No. 3RR- 14 Copy: NRC Region I Mr. A. J. Blamey, NRC Sr. Resident Inspector Mr. R. V. Guzman, NRC Sr. Project Manager Mr. R. R. Janati, DEP/BRP
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PPL SUSQUEHANNA, LLC SUSQUEHANNA SES, UNITS 1 AND 2 THIRD 10-YEAR INTERVAL RELIEF REQUEST NO. 3RR-14
Enclosure to PLA-6159 Page 1 of 9 PPL SUSQUEHANNA, LLC SUSQUEHANNA SES, UNITS 1 AND 2 THIRD 10-YEAR INTERVAL RELIEF REQUEST NO. 3RR-14 SYSTEM/COMPONENT(S) FOR WHICH RELIEF IS REQUESTED Category B-A, reactor pressure vessel (RPV) shell-to-flange weld AF (Item B 1.30) and head-to-flange weld AG (Item B 1.40).
CODE REQUIREMENTS Third interval examinations will be performed per the requirements of ASME Section XI, 1998 Edition through the 2000 Addenda, as amended by 10 CFR 50.55a.
The NRC amended the use of the 1998 Edition through the 2000 Addenda in Paragraph 10 CFR 50.55a(b)(2)(xxiv), which states, "The use of Appendix VIII and the supplements to Appendix VIII and Article 1-3000 of Section XI of the ASME BPV Code, 2002 Addenda through the latest edition and addenda incorporatedby reference in paragraph(b)(2) of this section, is prohibited." Therefore, when referencing Appendix VIII, licenses are limited to using the 2001 Code.
The RPV shell-to-flange weld and the head-to-flange weld are currently required to be examined per Appendix I, 1-2100(b) of the 1998 Edition of the ASME Section XI through the 2000 Addenda, which requires that the examination be conducted in accordance with Article 4, except that alternative beam angles may be used.
Additionally, there is a requirement to supplement the Section V examinations with Table 1-2000-1. Section T-472.1 of the 1998 Edition of Section V with the 2000 Addenda defines the ultrasonic scanning criteria for the examination of reactor vessel-to-flange welds and closure head-to-flange welds. ,These are:
" (T-472. 1.1) The beam angle shall be appropriate for the configuration being examined and that the beam angle shall be capable of detecting the calibration reflectors, over the required angle beam paths.
- (T-472.1.2) When scanning for reflectors parallel to the weld seam, the angle beam shall be directed at approximate right angles to the weld axis from both sides of the weld (i.e., from two directions) on the same surface when possible. The search unit shall be manipulated so that the ultrasonic energy passes through the required volume of weld and adjacent base material.
Enclosure to PLA-6159 Page 2 of 9
" (T-472.1.3) When scanning for reflectors transverse (perpendicular) to the weld seam, the angle beam shall be directed essentially parallel to the weld axis. The search unit shall be manipulated so that the ultrasonic energy passes through the required volume of weld and adjacent base material. The search unit shall be rotated 180 degrees and the examination repeated.
" (T-472.2) Welds that cannot be fully examined from two directions using the angle beam techniques shall also be examined if possible with a straight beam technique.
" (T-472.3) Welds that cannot be examined from at least one side (edge) using the angle beam technique shall be noted in the examination report. For flange welds, the weld may be examined with a straight beam or low angle longitudinal waves from the flange surface provided the examination volume can be covered.
RELIEF REQUESTED In lieu of the Article 4 of Section V angle beam examination, PPL proposes to use an angle beam examination that will be performed using examination procedures, personnel, and equipment qualified in accordance with Appendix VIII, Supplements 4 and 6, as amended by the conditions set forth in 10 CFR 50.55a..
BASIS FOR RELIEF Appendix VIII requirements were developed to ensure the effectiveness of UT examin-ations within the nuclear industry by means of a rigorous, item-specific performance demonstration. The performance demonstration (through PDI) was conducted on RPV mockups containing flaws of various size and allocations. The demonstration established the capability of equipment, procedures, and personnel to find flaws that could be detri-mental to the integrity of the RPV. The performance demonstration showed that for the detection of flaws in RPV welds, the UT techniques were equal to or surpassed the requirements of the Section V, Article 4 of the ASME Code. Additionally, the PDI qualified sizing techniques are considered to be more accurate than the techniques used in Article 4 of Section V.
Although Appendix VIII is not required for the RPV shell-to-flange weld and RPV head-to-flange weld, the use of Appendix VIII criteria for detection and sizing of flaws in these welds will be equal to or will exceed the requirements established by Article 4 of Section V. Therefore, the use of this proposed alternative will continue to provide an
Enclosure to PLA-6159 Page 3 of 9 acceptable level of quality and safety, and approval is requested pursuant to 10 CFR 50.55a(a)(3)(i).
ALTERNATIVE EXAMINATION In lieu of the Article 4 of Section V angle beam examination, PPL proposes to use an angle beam examination that will be performed using examination procedures, personnel, and equipment qualified in accordance with Appendix VIII, Supplements 4 and 6, as amended by the conditions set forth in 10 CFR 50.55a. Examination of each weld is described below: (See Figure 1)
AF - Vessel-to-Flange The Section XI required examination volume will be scanned for flaws from the outside of the vessel using a 60-degree refracted longitudinal wave; however, the curvature of the flange surface above the weld will limit transducer travel such that examinations can only be performed from the shell side. Additionally, the refueling bellows prevent examina-tions from being performed from the vertical portion of the flange surface located directly above the curvature. The projected single-side coverage for flaws located parallel to the weld is shown in Figures 2 and 3.'
Since the examination will be from a single side, the requirements of 10 CFR 50.55a (b)(2)(xvi)(A) apply. Therefore, examinations will be conducted with equipment, proce-dures, and personnel that have demonstrated proficiency with single-side examinations.
To demonstrate equivalency to two-sided examinations, the demonstration must be per-formed to the requirements of Appendix VIII as modified by this paragraph and 10 CFR 50.55a(b)(2)(xv)(B) through (G), on specimens containing flaws with non-optimuum sound energy reflecting characteristics or flaws similar to those in the vessel being examined. Examination of the Section XI required volume will be performed as follows:
Per 10 CFR 50.55a(b)(2)(xv)(G)(l), the clad-to-base metal interface, including a minimum of 15 percent T (measured from the clad-to-base metal interface), shall be examined from four orthogonal directions using procedures and personnel qualified in accordance with Supplement 4 to Appendix VIII.
Per 10 CFR 50.55a(b)(2)(xv)(G)(2), if the clad-to-base-metal-interface procedure demonstrates detectability of flaws with a tilt angle relative to the weld centerline of at least 45 degrees, the remainder of the examination volume is considered fully examined if coverage is obtained in one parallel and one perpendicular direction.
This must be accomplished using a procedure and personnel qualified for single-side examination in accordance with Supplement 6. Subsequent examinations of
Enclosure to PLA-6159 Page 4 of 9 this volume may be performed using examination techniques qualified for a tilt angle of at least 10 degrees.
Per 10 CFR 50.55a(b)(2)(xv)(G)(3), the examination volume not addressed by 10 CFR 50.50a(b)(2)(xv)(G)(1) is considered fully examined if coverage is obtained in one parallel and one perpendicular direction, using a procedure and personnel qualified for single-sided examination when the provisions of 10 CFR 50.55a(b)(2)(xv)(G)(2) are met.
AG - Closure Head-to-Flange Weld The Section XI required examination volume will be scanned for flaws using a 60-degree refracted longitudinal wave. Examinations will be performed from both the head and flange side of the weld; however, the short distance from the weld to the flange limits the examination on the flange side weld. The RPV head is not clad; therefore, when apply-ing Appendix VIII, only Supplement 6 would normally be required. However, instead of using Supplement 6 to perform the examination of the entire examination volume, guidance will be taken from Code Case N-664 (which applies to unclad vessel welds, excluding flanges), to perform the examination of the inner 15% of the examination volume per Supplement 4 of Appendix VIII. The outer 85% of the examination volume will be examined using Supplement 6. the application of Code Case N-664 (and thus the use of Supplement 4 for the inner 15% on this flange configuration) is considered to be an acceptable practice because the PDI qualification using Supplement 4 clad specimens is considered to be more difficult than the qualification using Supplement 6 specimens.
By using this approach, weld AG will be examined using the same requirements as specified above for weld AF. The projected coverage for flaws located parallel to the weld is shown in Figures 4 and 5.
JUSTIFICATION FOR GRANTING RELIEF Pursuant to 10 CFR 50.55a(a)(3)(i), approval is requested to use the proposed alternatives described above in lieu of the ASME Code Article 4 of Section'V. Compliance with the proposed alternatives will provide an adequate level of quality and safety for examination of the affected welds.
IMPLEMENTATION SCHEDULE The alternative program will be applicable to the Third 10-Year In-service Inspection Interval for Susquehanna SES Units 1 and 2.
Enclosure to PLA-6159 Page 5 of 9 Relief Request 3RR-14 Weld AG Weld AF NOTE, SCALE IN INCHES ABOVE VESSEl. ZERO Figure 1 Location of Welds
Enclosure to PLA-6159 Page 6 of 9 Relief Request 3RR-14 Weld 'AF 60 S6 Exam Volume = 64.2 Sq. In.
60' S4 Exam Volume = 12.4 Sq. In.
60 T-Scan achieved = 56.1 Sa. In.
60' S4 T-Scan achieved = 12.4 Sq.
60" S6 P-Scan achieved = 37.6 Sq.
60( S4 P-Scan achieved = 6.6 Sq.
100% of the weld nugaet examined single sided demonstra ed techniques for flaws parallel to the weld axis.
Figure 2 Susquehanna SES Unit 1 AF - Vessel-to-Flange Weld
Enclosure to PLA-6159 Page 7 of 9 Relief Request 3RR-14 r
Weld 'AF 60 S6 Exam Volume = 64.2 Sq. In.
60 S4 Exam Volume = 12.4 Sq. In.
60 T-Scan achieved = 56.1 Sq. In.
60' S4 T-Scan achieved = 12.4 Sq.
60' S6 P-Scan achieved = 37.6 Sq.
60* S4 P-Scan achieved = 6.6 Sq.
100% of the weld nugvet examined single sided demonstra ed techniques for flaws parallel to the weld axis.
Figure 3 Susquehanna SES Unit 2 AF - Vessel-to-Flange Weld
Enclosure to PLA-6159 Page 8 of 9 Relief Request 3RR-14 Weld AG 60 S6 Exam Volume = 37 4 Sq In 60" S4 Exam Volume = N/A Unclad 60 S6 T-Scan achieved = 34 7 Sq. In.
660" S4 T-Scan achieved = N/A Unclad
- 60 S6 P-Scan achieved = 25 Sq. In.
60* S4 P-Scan achieved = N/A Unclad ro)
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- 3, Figure 4 Susquehanna SES Unit 1 AG - Closure Head-to-Flange Weld
Enclosure to PLA-6159 Page 9 of 9 Relief Request 3RR-14
,Weld AG 6(T S6 Exam Volume = 37N4 Sq In 60( S4 Exam Volume =N/A Unad 60" S6 T-Scan achieved = 34 7 Sq In.
60C S4 T-Scan achieved N/A Unclad 60 S6 P-Scan ochieved = 25 Sq. In.
60I S4 P-Scan achieved = N/A Unclad
-a Figure 5 Susquehanna SES Unit 2 AG - Closure Head-to-Flange Weld