ML110110172
| ML110110172 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 02/03/2011 |
| From: | Markley M Plant Licensing Branch IV |
| To: | Reddeman M Energy Northwest |
| Singal, Balwant, 415-3016, NRR/DORL/LPL4 | |
| References | |
| TAC ME3582, TAC ME3714 | |
| Download: ML110110172 (25) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 3, 2011 Mr. Mark E. Reddemann Chief Executive Officer Energy Northwest P.O. Box 968 (Mail Drop 1023)
Richland, WA 99352-0968
SUBJECT:
COLUMBIA GENERATING STATION - RELIEF REQUESTS 31SI-10 AND 31SI-11 FOR THE THIRD 10-YEAR INSERVICE INSPECTION PROGRAM (TAC NOS. ME3582 AND ME3714)
Dear Mr. Reddemann:
By letter dated March 11, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML100770221), as supplemented by letter dated September 28,2010 (ADAMS Accession No. ML102780484), Energy Northwest (the licensee) requested U.S.
Nuclear Regulatory Commission (NRC) approval of Relief Request (RR) 31SI-1 0 and RR 31SI-11 for Columbia Generating Station (CGS) for its third 10-year inservice inspection (lSI) program. In RR 31SI-10, the licensee requested approval for use of an updated method for the inspection of Reactor Pressure Vessel shell-to-flange weld and head-to-flange weld at CGS. In RR 31SI-11, the licensee requested approval to use the requirements of BWRVIP-75-A, "BWR
[Boiling-Water Reactor1 Vessel and Internals Project, Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules," in lieu of the American Society of Mechanical Engineers, Boiler and Pressure Vessel Code (ASME Code),Section XI and other augmented requirements for the examination of Category B-J, Item B9.11 dissimilar metal welds Nominal Pipe Size 4-inch or larger.
The NRC staff has completed its review of the subject relief requests. Based on the enclosed safety evaluation, the NRC staff concludes that the licensee's proposed alternatives contained in RRs 31S1-10 and RR 31SI-11 provide an acceptable level of quality and safety. Therefore, in accordance with Title 10 of the Code of Federal Regulations (10 CFR), paragraph 50.55a(a)(3)(i), the proposed alternatives are authorized for the third 10-year lSI interval at CGS.
All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
M. Reddeman - 2 If you have any questions regarding this matter, please contact the NRC project manager, Balwant Singal, at (301) 415-3016 or via e-mail at balwant.singal@nrc.gov.
Sincerely, J:.U;:~rk~~ f
\ Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-397
Enclosure:
As stated cc w/encl: Distribution via Listserv
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST NOS. 31SI-10 AND 31SI-11 DURING THIRD 10-YEAR INSERVICE INSPECTION PROGRAM COLUMBIA GENERATING STATION ENERGY NORTHWEST DOCKET NO. 50-397
1.0 INTRODUCTION
By letter dated March 11, 2010 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML100770221), as supplemented by letter dated September 28,2010 (ADAMS Accession No. ML102780484), Energy Northwest (the licensee) requested U.S.
Nuclear Regulatory Commission (NRC) approval of Relief Requests (RRs) 31SI*10 and 31SI-11 for Columbia Generating Station (CGS) in accordance with Title 10 of the Code of Federal Regulations (10 CFR), paragraph 50.55a(a)(3)(i). In both RRs, the licensee requested NRC approval of proposed alternatives to the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI inspection requirements regarding examination of the reactor pressure vessel (RPV) circumferential shell-to-flange weld and the RPV closure head-to-flange weld, and use of the BWRVIP-75-A, "BWR [Boiling-Water Reactor]
Vessel and Internals Project, Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules," for nozzle-to-safe end butt welds and dissimilar metal welds of nominal pipe size (NPS) 4-inch or larger, respectively.
2.0 REGULATORY EVALUATION
Inservice inspection (lSI) of the ASME Code, Class 1, 2, and 3 components is performed in accordance with Section XI of the ASME Code and applicable addenda as required by 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 regulations in 10 CFR 50.55a(a)(3) state that alternatives to the requirements of paragraph (g) may be used, when authorized by the Director of the Office of Nuclear Reactor Regulation 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.
The regulations in 10 CFR 50.55a(g)(4) further state that ASME Code Class 1,2, and 3 components (including supports) must meet the requirements, except design and access Enclosure
-2 provisions and 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 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 applicable lSI Code of record for the third 10-year lSI interval for CGS is the 2001 Edition through the 2003 Addenda of the ASME Code,Section XI.
In addition, for ultrasonic (UT) examinations, the licensee will follow the Electric Power Research Institute's (EPRl's) "Performance Demonstration for Ultrasonic Examination Systems," of the ASME Code,Section XI, Appendix VIII of the 2001 Edition in accordance with 10 CFR 50.55a(b)(2)(xv) and as amended by 10 CFR 50.55a(b)(2)(xv)(B) through (G) and 10 CFR 50.55a(b)(2)(xvi)(A).
3.0 TECHNICAL EVALUATION
3.1 RR 31SI-1 0, ASME Code,Section XI, Examination Category B-A, Items B1.30 and B1.40 - Pressure Retaining Welds in RPV Components for Which Relief is Requested RPV Shell-to-Flange Weld AE (Code Category B-A, Item No. B1.30)
Top Head-to-Flange Weld AG (Code Category B-A, Item No. B1.40)
ASIVIE Code Class ASME Code Class 1 ASME Code Requirements (as stated by the licensee)
The NRC amended the use of the 2001 Edition through the 2003 Addenda in 10 CFR 50. 55a(b)(2)(xxiv), which states, "The use of [ASME Code,Section XI, Appendix VIII] and the supplements to Appendix VIII and Article 1-3000 of ASIVIE Section XI of the ASME BPV [Boiler and Pressure Vessel] Code, 2002 Addenda through the latest edition and addenda incorporated by reference in paragraph (b)(2) of this section, is prohibited." Therefore, when referencing [ASME Code,Section XI, Appendix VIII], licensees are limited to using the 2001 [ASME] Code.
The RPV shell-to-flange weld and the head-to-flange weld are currently required to be examined per Appendix I, 1-2110(b) of the 2001 Edition of the [ASME Code, Section XI] through the 2003 Addenda, which requires that the examination be conducted in accordance with [ASME Code,Section V, Article 4], except that alternative beam angles may be used. Additionally, there is a requirement to supplement the [ASME Code, Section V] examinations with Table 1-2000-1.
Section T-472.1 of the 2001 Edition of [ASME Code, Section V] with the 2003
-3 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.
- (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.
Licensee's Proposed Alternative (as stated by the licensee)
In lieu of the Article 4 of [ASME Code, Section Vl angle beam examination,
[CGS] proposes to use an angle beam examination that will be performed using examination procedures, personnel, and equipment qualified in accordance with
[ASME Code,Section XI, Appendix VIII, Supplements 4 and 6], as amended by the conditions set forth in 10 CFR 50.55a.
Licensee's Basis for Relief Request (as stated by the licensee)
[ASME Code,Section XI, Appendix VIII] requirements were developed to ensure the effectiveness of UT examinations within the nuclear industry by means of a rigorous, item-specific performance demonstration. The performance demonstration was conducted through industry's Performance Demonstration Initiative (POI) on RPV mockups containing flaws of various size and allocations.
The demonstration established the capability of equipment, procedures, and
-4 personnel to find flaws that could be detrimental 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 [ASME Code,Section V, Article 4]. Additionally, the PDI qualified sizing techniques are considered to be more accurate than the techniques used in [ASME Code,Section V, Article 4.]
Although [ASME Code,Section XI, Appendix VIII] is not required for the RPV shell-to-flange weld and RPV head-to-flange weld, the use of [ASME Code,Section XI, Appendix VIII] criteria for detection and sizing of flaws in these welds will be equal to or will exceed the requirements established by [ASME Code,Section V, Article 4.] Therefore, the use of this proposed alternative will continue to provide an acceptable level of quality and safety, and approval is requested pursuant to 10 CFR 50.55a(a)(3)(i).
AE - Vessel-to-Flange Weld The [ASME Code, Section XI] required examination volume will be scanned for flaws from the outside of the [RPV] using a 50-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 examinations 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 Figure 2 [(of the submittal dated March 11, 2010)]. 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, procedures, and personnel that have demonstrated proficiency with single-side examinations. To demonstrate equivalency to two-sided examinations, the demonstration must be performed to the requirements of [ASME Code,Section XI, Appendix VIII] as modified by this paragraph and 10 CFR 50.55a(b)(2)(xv)(8) through (G), on specimens containing flaws with non-optimum sound energy reflecting characteristics or flaws similar to those in the vessel being examined.
Examination of the [ASME Code, Section XI] required volume will be performed as follows:
- Per 10 CFR 50. 55a(b)(2)(xv)(G)(1 ), 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 [ASME Code,Section XI, Appendix VIII, Supplement 4].
- 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
-5 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 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 50.55a(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 [ASME Code, 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 applying [ASME Code,Section XI, Appendix VIII], only Supplement 6 would normally be required.
However, instead of using [ASME Code,Section XI, Appendix VIII, Supplement 6] to perform the examination of the entire examination volume, guidance will be taken from Code Case N-664[1 j (which applies to unclad vessel welds, excluding flanges), to perform the examination of the inner 15% of the examination volume per [ASME Code,Section XI, Appendix VIII, Supplement 4].
The outer 85% of the examination volume will be examined using [ASME Code,Section XI, Appendix VIII, Supplement 6]. The application of Code Case N-664 (and thus the use of [ASME Code,Section XI, Appendix VIII, Supplement 4] for the inner 15% on this flange configuration) is an acceptable practice because the POI qualification using [ASME Code,Section XI, Appendix VIII, Supplement 4]
clad specimens requires examiners to demonstrate more proficiency than the qualification using [ASME Code,Section XI, Appendix VIII, Supplement 6]
specimens. By using this approach, weld AG will be examined using the same requirements as specified above for weld AE. The projected coverage for flaws located parallel to the weld is shown in Figure 3 [(see the licensee's submittal dated March 11, 2010.)]'
NRC Staff Evaluation
The ASME Code requires that prescriptive UT requirements found in ASME Code,Section V, Article 4 be employed for examining RPV Shell-to-Flange Weld AE and RPV Head-to-Flange Weld AG, respectively. As an alternative to those prescriptive requirements, the licensee has proposed to use the techniques, personnel, and equipment qualified to meet the requirements ASME Code Case N-664, "Performance Demonstration Requirements for Examination of Unclad Reactor Pressure Vessel Welds, Excluding Flange Welds,Section XI, Division 1," has been approved for general use in Regulatory Guide 1.147, Revision 15, "Inservice Inspection Code Case Acceptability ASME Section XI, Division 1."
- 6 of ASME Code,Section XI, Appendix VIII, Supplements 4 and 6 of the 2001 Edition, in accordance with 10 CFR 50.55a(b)(2)(xv) and as amended by Sections 10 CFR 50.55a(b)(2)(xv)(8) through (G) and 10 CFR 50.55a(b)(2)(xvi)(A), by following the EPRI POI processes.
UT performance-based techniques are based on the ability of personnel, procedures and equipment to detect and characterize simulated flaws in specimens that are typical of components found in the field. These methods are required by 10 CFR 50.55a for RPV shell and head welds, piping welds, dissimilar metal welds, and bolting. The performance demonstration examinations are believed more sensitive for detecting flaws than ASME Code,Section V, Article 4 methods, which are based on amplitude thresholds determined via calibration blocks with machined reflectors, because the examination sensitivity levels, detailed procedure criteria, and blind demonstrations enhance and verify their effectiveness. As such, the POI-qualified procedures generally provide a higher probability of detection than prescriptive-based methods.
Therefore, based on the enhanced properties of UT techniques qualified through ASME Code,Section XI, Appendix VIII requirements, the NRC staff concludes that the licensee's proposal provides an acceptable level of quality and safety.
3.2 Request for Relief 31SI-11, ASME Code,Section XI, Examination Categories 8-F and 8-J, Items 85.10 and 89.11 - RPV Nozzle-to-Safe End 8utt Welds NPS 4 or Larqer and Dissimilar Metal Circumferential Welds NPS 4 or Larger Not Included in Category 8-F Components for Which Relief is Requested Table 1 ASME ASME Code ASME Code Examination Code Item Class Category Number Description 1 8-F 85.10 Reactor Vessel Nozzle-to-Safe End 8utt Welds, NPS 4 or larger 1 8-J 89.11 Dissimilar metal circumferential welds NPS 4 or larger not included in Category 8-F A list of the affected welds is contained in the Table 2 as an attachment to this safety evaluation (SE).
ASME Code Requirements (as stated by the licensee)
[ASME Code,Section XI, Subsection IW8-2412] requires the percentage of examinations be completed in accordance with Table IW8-2412-1, exceptfor the examinations that may be deferred until the end of the Inspection Interval.
Table IW8-2412-1 defines a minimum and maximum number of examinations to be performed each inspection period.
-7 (CGS] relief request 3ISI-08, authorized by NRC letter dated 12/3/2008[2], defines the scope of the risk-informed inservice inspection program for Category 8-J welds. This program excludes the dissimilar metal welds of Category 8-J.
Examination of Category 8-J dissimilar metal welds is defined in Table IW8-2500-1.
[ASME Code,Section XI, Subsection IW8-2500] requires components to be examined as specified in Table IW8-2500-1. Table IW8-2500-1 column headed "Extent and Frequency of Examination" requires that all Category 8-F welds and all dissimilar metal 8-J welds be examined over the ten-year lSI interval as described in items 85.10 and 89.11 below:
Item 85.10 Examine the reactor vessel nozzle-to-safe end butt welds, NPS 4 or larger, by volumetric and surface examination method.
Item 89.11 Examine piping circumferential welds NPS 4 or larger by volumetric and surface examination method. Per Note (1 )(c) examinations shall include all dissimilar metal welds not covered under Category 8-F.
These welds are also covered by the augmented examination requirements of NUREG-0313[3j and GL 88-01[41, including Supplement 1[5]. Energy Northwest implemented the inspection schedules of 8WRVIP-75 for this augmented program in [its letters dated February 9,2001 (ADAMS Accession No. ML010510129), and April 9, 2001 (ADAMS Accession No. ML010990083)].
Licensee's Proposed Alternative (as stated by the licensee)
In lieu of the requirements of [ASME Code, Section XI], 2001 Edition, 2003 Addenda, the proposed alternative described below shall be used.
Energy Northwest will examine the affected [ASME Code,Section XI,]
Category 8-F and 8-J welds [(See Table 2 in Attachment to this SE)] in accordance with the 8WRVIP-75-A schedule and frequency for normal water 2 Markley, M. T., U.S. Nuclear Regulatory Commission, letter to J. V. Parrish, Energy Northwest, "Columbia Generation Station Request for Relief No. 31SI-08 for the Third 10-Year Inservice Inspection Program Interval (TAC No. MD7507)," dated December 3,2008 (ADAMS Accession No. ML083220206).
3 U.S. Nuclear Regulatory Commission, "Technical Report on Material Selection and Processing Guidelines for BWR Coolant Pressure Boundary Piping," NUREG-0313, Revision 2, January 1988 (ADAMS Accession No. ML031470422).
4 U.S. Nuclear Regulatory Commission, "NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping (Generic Letter 88-01 )," dated January 25, 1988 (ADAMS Accession No. ML031130463).
5 U.S. Nuclear Regulatory CommiSSion, "NRC Position on Intergranular Stress Corrosion Cracking (IGSCC) in BWR Austenitic Stainless Steel Piping (Generic Letter 88-01, Supplement 1)," dated February 4, 1992 (ADAMS Accession No. ML031130421).
- 8 chemistry, as defined by the NRC Final Safety Evaluation[61. The examination methods listed in [ASME Code,Section XI,] Table IWB-2500-1 are not affected by this request.
Licensee's Basis (as stated by the licensee)
By letter dated May 14, 2002[7], the NRC issued their Final Safety Evaluation (SE) on BWRVIP-75. In that Safety Evaluation, the NRC staff concluded that, "licensee implementation of the guidelines of BWRVIP-75 report, as modified, will provide an acceptable level of quality for inspection of the safety-related components addressed". Additionally, the NRC concluded that, "the revised BWRVIP-75 guidance is acceptable for licensee referencing as the technical basis for relief from, or as an alternative to, the ASME Code and 10 CFR
[50.55a], in order to use the sample schedules and frequencies specified in the revised BWRVIP-75 report that are less than those required by the ASME Code'"
BWRVIP-75-A is the updated version of the report which incorporated changes by BWRVIP in response to recommendations in the NRC SE and other necessary revisions identified since the previous publication of the report.
BWRVIP-75-A was approved by the NRC March 16, 2006[6].
The licensee provided additional information for the basis for relief regarding BWR water chemistry for CGS in its supplemental letter dated September 28,2010, which states:
CGS uses the latest version of the EPRI BWR Water Chemistry Guidelines, (BWRVIP-190) for control of the unit's water chemistry. BWRVIP-130 is a previous version of the EPRI BWR Water Chemistry Guidelines. Initial Noble Metal Chemical Addition (NMCA) application was completed May 2001, followed by implementation of Hydrogen Water Chemistry (HWC) in November 2004. The second application of NMCA was performed in May 2007. Through August 2010 HWC availability has been 97.9% for current operating cycle and 98.4% since starting HWC in November 2004.
CGS follows the guidance of BWRVIP-62 for evaluating effective implementation of HWC with NMCA. BWRVIP-62 outlines the approaches that may be used to demonstrate that HWC is effectively implemented. The goal of an effective HWC mitigation plan is to reduce an electrochemical corrosion potential (ECP) at the metal surface during normal operation thereby providing protection against IGSCC. The approach used depends on the HWC process employed (Le.,
HWC-Moderate or NMCA) and may be further influenced by whether ECP measurements are made. The monitoring requirements for establishing and maintaining an effective control program are found in BWRVIP-62.
6 Bateman, W. H., U.S. Nuclear Regulatory Commission, letter to B. Eaton, BWRVIP Chairman, "NRC Approval Letter for BWRVIP-75-A, "BWR Vessel and Internals Project, Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules," dated March 16,2006 (ADAMS Accession No. ML060760028).
7 Bateman, W. H., U.S. Nuclear Regulatory CommiSSion, letter to C. Terry, BWRVIP Chairman, "Final Safety Evaluation ofthe 'BWRVIP Vessel and Internals Project, BWR Vessel and Internals Project, Technical Basis For Revisions To Generic Letter 88-01 Inspection Schedules (BWRVIP-75),' EPRI Report TR-113932, October 1999 (TAC No. MA5012)," dated May 14, 2002 (ADAMS Accession No. ML021350645).
-9 CGS is currently a Category 3a plant per BWRVIP-62 guidance, meaning that CGS is an NMCA plant with ECP monitoring. As such, CGS complies with the following primary and secondary monitoring methods:
Primary Parameters:
- Measured ECP
- Monitoring of Catalyst loading Secondary Monitoring Parameters include the following:
- Measured Reactor water dissolved oxygen concentration
NRC Staff Evaluation
ASME Code,Section XI, Table IWB-2500-1, Category B-F, Item B5.10 requires examination of accessible areas of the reactor vessel nozzle-to-safe end butt welds, NPS 4 and larger, by volumetric and surface examination methods. ASME Code,Section XI, Table IWB-2500-1, Category B-J, Item 9.11 requires examination of pressure retaining welds in piping dissimilar metal circumferential welds NPS 4 or larger not included in Category B-F.
The licensee proposes to examine the affected ASME Code,Section XI, Category B-F and B-J .
welds in Table 2 (see Attachment to this SE) in accordance with the BWRVIP-75-A schedule and frequency for normal water chemistry, as defined by the NRC Final Safety Evaluation dated March 16,2006. The licensee also noted that the examination methods listed in ASME Code,Section XI, Table IWB-2500-1 are not affected by this request.
The BWRVIP-75 report was submitted to the NRC for staff review by letter dated October 27, 1999 B* The BWRVIP-75 report proposed revisions to the scope and frequencies of inspections of Category A through E welds as defined in GL 88-01 and NUREG-0313, Revision 2 for both normal water chemistry and HWC conditions. The proposed revisions were based on the consideration of inspection results and service experience gained by the industry since the issuance of GL 88-01 and included additional knowledge regarding the benefits of improved BWR water chemistry. The NRC staff reviewed the BWRVIP-75 report, as supplemented, and concluded that the revised guidance of the BWRVIP-75 report, with the modifications as described in the NRC staff's final SE is acceptable for inspection of the subject safety-related ASME Code, Class 1 piping welds.
6 Terry, C., BWR Vessel and Internals Project. letter to U.S. Nuclear Regulatory CommisSion, "Project 704
'BWRVIP Vessel and Internals Project, Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules (BWRVIP-75): EPRI Report TR-113932, October 1999," dated October 27,1999 (ADAMS Accession No. ML993080249).
- 10 The licensee noted that CGS uses the latest version of the EPRI BWR Water Chemistry Guidelines, BWRVIP-190, for control of the unit's water chemistry. In addition, the licensee follows the guidance of BWRVIP-62 for evaluating effective implementation of HWC with NMCA.
This provides for an effective HWC mitigation plan to reduce the ECP at the metal surface during normal operation and providing protection against IGSCC. The licensee also noted that CGS is currently a Category 3a plant per the BWRVIP-62 guidance, meaning that CGS is an NMCA plant with ECP monitoring.
For volumetric non-destructive examination by the UT methodology of Category A piping at CGS, the licensee will use personnel and procedures complying with the EPRI PDI, under the ASME Code,Section XI, Appendix VII and Appendix VIII requirements.
The licensee's proposed alternative examination would use sample scope and frequencies specified in the BWRVIP-75 report for normal water chemistry in lieu of those required by the ASME Code. Based on the above, the NRC staff concludes that licensee's implementation of the guidelines in the BWRVIP-75 report, as modified, will provide an acceptable level of quality for inspection of the safety-related components addressed. Further, the NRC staff concludes that the BWRVIP-75 guidance, as revised by the NRC staffs final SE dated May 14, 2002, is acceptable for licensee referencing as the technical basis for relief from, or as an alternative to, the ASME Code and 10 CFR 50.55a.
While these proposed inspections can be credited toward ASME Code,Section XI requirements, inspections of those welds outside the GL 88-01 scope are not affected and are not included in this relief approval. The findings and conclusions in the NRC staff's final BWRVIP-75 SE are not applicable to any welds or piping (e.g., socket welds, carbon steel piping, etc.) other than those within the original scope of GL 88-01 and NUREG-0313, Revision 2 (Le., those in BWR piping made of austenitic stainless steel 4 inches or larger in nominal diameter and exposed to reactor coolant at a temperature above 200 degrees Fahrenheit during power operation, and to RPV attachments and appurtenances).
4.0 CONCLUSION
Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(a)(3)(i), and is in compliance with the requirements of 10 CFR 50.55a with the authorizing of this relief. Therefore, the staff concludes that the licensee's proposed alternatives contained in RR 31SI-10 and RR 31SI-11 provide an acceptable level of quality and safety, and are in accordance with 10 CFR 50.55a(a)(3)(i), and the proposed alternatives are authorized for the third 10-year lSI interval at CGS.
All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: Thomas McLellan Date: February 3, 2011
RELIEF REQUESTS 31SI*10 AND 31SI*11 FOR THE THIRD 10-YEAR lNSERVICE INSPECTION PROGRAM COLUMBIA GENERATING STATION DOCKET NO. 50-397 Table 2 ASME ASMECode Item BWRVIP*75-A Material See Identification Number Description Category Number Category Note Number Mitigation Drawing 1OHPCS(1 )-4 Safe-end to Nozzle B-F B5.10 C 4 MSIP RPV-109 1OlPCS(1 )-4 Safe-end to Nozzle B-F 85.10 C 4 MSIP RPV-109 12RFW(1)AC-13 Safe-end to Nozzle 8-F B5.10 C 4 MSIP RPV-108 12RFW(1 )AB-11 Safe-end to Nozzle B-F B5.10 C 4 MSIP RPV-108 12RFW(1)M-11 Safe-end to Nozzle B-F 85.10 C 4 MSIP RPV-108 12RFW(1)BF-14 Safe-end to Nozzle 8-F B5.10 C 4 MSIP RPV-108 12RFW(1 )BE-11 Safe-end to Nozzle B-F B5.10 C 4 MSIP RPV-108 12RFW(1)BD-11 Safe-end to Nozzle 8-F 85.10 C 4 MSIP RPV-108 12lPCI(1 )A-6 Safe-end to Nozzle 8-F B5.10 C 4 MSIP RPV-110 12LPCI(1)B-6 Safe-end to Nozzle 8-F 85.10 C 4 MSIP RPV-110 12lPCI(1)C-6 Safe-end to Nozzle 8-F B5.10 C 4 MSIP RPV-110 4JP(NZ)A-1 Safe-end to Nozzle B-F B5.10 C 1 MSIP RPV-115 4JP(NZ)B-1 Safe-end to Nozzle 8-F 85.10 C 1 MSIP RPV-115 24RRC(2)A-1 Safe-end to Nozzle B-F B5.10 C 2 MSIP RPV-105 12RRC(1 )-N2A-6 Safe-end to Nozzle B-F B510 C 3 MSIP RPV-106 12RRC(1)-N2B-6 Safe-end to Nozzle 8-F 85.10 C 3 MSIP RPV-106 12RRC(1 )-N2C-6 Safe-end to Nozzle B-F 85.10 C 3 MSIP RPV-106 12RRC(1 )-N2D-6 Safe-end to Nozzle 8-F B5.10 C 3 MSIP RPV-106 12RRC(1 )-N2E-6 Safe-end to Nozzle B-F B5.10 C 3 MSIP RPV-106 24RRC(2)B-1 Safe-end to Nozzle 8-F 85.10 C 2 MSIP RPV-105 12RRC(1)-N2F-6 Safe-end to Nozzle B-F B5.10 C 3 MSIP RPV-106 12RRC(1)-N2G-6 Safe-end to Nozzle 8-F B5.10 C 3 MSIP RPV-106 12RRC(1)-N2H-6 Safe-end to Nozzle B-F B5.10 C 3 MSIP RPV-106 12RRC(1 )-N2J-6 Safe-end to Nozzle B-F 85.10 C 3 MSIP RPV-106 12RRC(1 )-N2K-6 Safe-end to Nozzle B-F 85.10 C 3 MSIP RPV-106 1OHPCS( 1)-3 Safe-end Extension to Safe-end 8-J B9.11 A 6 MSIP RPV-109 1OlPCS( 1)-3 Safe-end Extension to Safe-end B-J B9.11 A 6 MSIP RPV-109 12RFW(1)AC-11 Safe-end Extension to Safe-end Stub 8-J B9.11 A 7 MSIP RPV-108 12RFW(1 )AB-9 Safe-end Extension to Safe-end Stub 8-J B9.11 A 7 MSIP RPV-108 12RFW(1)M-9 Safe-end Extension to Safe-end Stub 8-J 89.11 A 7 MSIP RPV-108 12RFW(1 )8F-12 Safe-end Extension to Safe-end Stub 8-J B9.11 . .
A 7 MSIP RPV-108 Attachment
-2 ASME ASMECode Item BWRVIP-75-A Material See Identification Number Description Category Number Category Note Number Mitigation Drawing 12RFW(1 )8E-9 Safe-end Extension to Safe-end Stub 8-J 89.11 A 7 MSIP RPV-108 12RFW(1 )8D-9 Safe-end Extension to Safe-end Stub 8-J 89.11 A 7' MSIP RPV-108 12LPCI(1)A-5 Safe-end Extension to Safe-end 8-J 89.11 A 6 MSIP RPV-110 12LPCI(1 )8-5 Safe-end Extension to Safe-end 8-J 89.11 A 6 MSIP RPV-110 12LPCI(1)C-5 Safe-end Extension to Safe-end 8-J 89.11 A 6 MSIP RPV-110 20RHR(2)-2 Safe-end to Valve 8-J 89.11 8 8 IHSI Figure 1 12RHR(1)A-14 Valve to Safe-end 8-J 89.11 8 9 IHSI Figure 2 12RHR(1)8-10 Valve to Safe-end 8-J 89.11 8 9 IHSI Figure 2 4JP(NZ)A-2 Safe-end to Fitting 8-J 89.11 A 5 MSIP RPV-115 4JP(NZ)8-2 Safe-end to Fitting 8-J 89.11 A 5 MSIP RPV-115 4RRC(4)A-11 Safe-end to Valve 8-J 89.11 8 10 IHSI Figure 3 4RRC(4)8-12 Safe-end to Valve 8-J 89.11 8 10 IHSI Figure 3 Abbreviations:
HPCS - High Pressure Core Spray IHSI - Induction Heating Stress Improvement JP - Jet Pump LPCI - Low Pressure Core Injection LPCS - Low Pressure Core Spray MSIP - Mechanical Stress Improvement Process NZ - Nozzle RFW - Reactor Feed water RHR - Residual Heat Removal RRC - Reactor Recirculation Notes:
- 1. SA 508 CI2 nozzle, buttered with Inconel 182 weld metal, welded to 336 F8 (0.025 C) Safe end with Inconel 82 weld metal.
- 2. SA 508 CI2 nozzle, buttered with Inconel182 weld metal. Post weld heat treated. Welded to SA 336 F8 Safe end (with 0.020 carbon content) with Inconel82 weld metal for root/hot pass and Inconel182 for balance.
- 3. SA 508 CI2 nozzle, buttered with Inconel182. Originallnconel600 safe-end removed. New 316L safe end with Inconel182 butter on the nozzle side of the safe end welded to originallnconel 182 buttering with Inconel 82 weld metal for the butt weld. Originallnconel 182 buttering with Inconel 82 weld metal for the butt weld.
- 4. Inconel182 buttering on safe end welded to Inconel600 SE with Inconel182 weld metal root/hot pass and Inconel182 for balance.
- 6. Inconel 600 safe end welded to carbon steel safe end extension with Inconel 82 weld material exposed to the fluid media.
- 7. Inconel600 safe end, stub, and carbon steel safe end extension welded with Inconel82 weld material exposed to the fluid media.
- 8. Valve body SA-352 welded to SA-182 F316 transition pipe (safe end) with SFA 5.4 filler material.
- 9. Valve body SA-350 welded to SA-182 F304 transition pipe (safe end) with SFA 5.4 filler material.
- 10. Valve body SA-350 welded to SA-182 F316 transition pipe (safe end) with SFA 5.1 and SFA 5.4 filler material.
M. Reddeman -2 If you have any questions regarding this matter, please contact the NRC project manager, Balwant Singal, at (301) 415-3016 or via e-mail at balwant.singal@nrc.gov.
Sincerely, IRA by James R. Hall fori Michael T. Markley, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-397
Enclosure:
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