ML042300476
| ML042300476 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Mcguire, Catawba  |
| Issue date: | 08/06/2004 |
| From: | Barron H Duke Energy Corp, Duke Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML042300476 (18) | |
Text
I -
If Duke HENRYB.BARRON
!iPowere Group VP, Nuclear Generation and Chief Nuclear Officer A Duke Energy Company Duke Power EC07H / 526 South Church Street Charlotte, NC 28202-1802 August 6, 2004 Mailing Address:
PO Box 1006 EC07H U. S. Nuclear Regulatory Commission Charlotte, NC 28201-1006 Washington, D.C. 20555-0001 704 382 2200 704 382 6056 fax ATTENTION: Document Control Desk hbarron @duke-energy. corn
SUBJECT:
Duke Energy Corporation Oconee Unit 3 Docket No. 50-287 McGuire Nuclear Station, Units 2 Docket No. 50-370 Catawba Nuclear Station, Units 1 & 2 Docket Nos. 50-413, 50-414 Relief Request for Alternative to ASME Section XI Relief Request 04-GO-001 Pursuant to 10 CFR 50.55a (a) (3) (i), Duke Energy Corporation (Duke) requests the use of an alternative to the ASME Boiler Section XI, Figures IWB-2500-7 (a) and (b), 1989 Edition with no addenda for the Reactor Pressure Vessel (RPV) examinations scheduled for the fall 2004 outages at Catawba Unit 2 and Oconee Unit 3; and the spring 2005 outages at McGuire Unit 2 and Catawba Unit 1.
Specifically, Duke requests relief from the requirement to perform volumetric examination of the RPV nozzle welds using the requirements of ASME Section XI, Figures IWB-2500-7 (a) and (b) 1989 Edition with no addenda. Duke requests approval to use, as an alternate, Code Case N-613-1 to examine the RPV Nozzle-to-Vessel Welds at McGuire Unit 2, Oconee Unit 3 and Catawba Units I and 2.
A detailed description of the proposed alternative and justification is included as an attachment to this letter. Duke is requesting approval of this request by September 23, 2004 to support the fall outages for Catawba Unit 2 and Oconee Unit 3. Questions regarding this request may be directed to M. H. Hazeltine at 704-382-5880.
Very truly yours, Henry B. Barron www. dukepower. corn q1
U. S. Nuclear Regulatory Commission August 6, 2004 Page 2 Attachment xc wlatt: W. D. Travers, Regional Administrator U. S. Nuclear Regulatory Commission, Region II Sam Nunn Atlanta Federal Center 23T85 61 Forsyth St., SW Atlanta, GA 30303 L. N. Olshan (Addressee only)
NRC Senior Project Manager (ONS)
U. S. Nuclear Regulatory Commission Mail Stop 0-8 H12 Washington, DC 20555-0001 J. J. Shea (Addressee only)
NRC Senior Project Manager (MNS)
U. S. Nuclear Regulatory Commission Mail Stop 0-8 H12 Washington, DC 20555-0001 S. E. Peters (Addressee only)
NRC Project Manager (CNS)
U. S. Nuclear Regulatory Commission Mail Stop 0-8 H12 Washington, DC 20555-0001 M. E. Shannon, NRC Senior Resident Inspector (ONS)
J. B. Brady, NRC Senior Resident Inspector (MNS)
E. F. Guthrie, NRC Senior Resident Inspector (CNS)
U. S. Nuclear Regulatory Commission August 6, 2004 Page 3 bxc w/ att: R. L. Gill (ECO50)
C. J. Thomas (MGOIRC)
K. L. Crane (MGOIRC)
N. T. Simms (MGOIRC)
L. A. Keller (CNOIRC)
K. E. Nicholson (CNO1RC)
L. J. Rudy (CNOIRC)
B. G. Davenport (ON03RC)
J. E. Smith (ON03RC)
R. P. Todd (ON03RC)
J. M. Ferguson - Date File (CNOISA)
R. K. Rhyne (EC05A)
J. J. McArdle (EC05A)
North Carolina Municipal Power Agency Number I Saluda River Electric Cooperative, Inc.
Piedmont Municipal Power Agency North Carolina Electric Membership Corporation MNS MasterFile MC-801.01 (MGOlDM)
CNS MasterFile CN-801.01 (CN04DM)
ONS MasterFile ON-801.01 (ON03DM)
ELL
04-GO-001 Page 1 of 3 Duke Energy Corporation CATAWBA UNITS I AND 2 McGUIRE UNIT 2 OCONEE UNIT 3 REQUEST FOR RELIEF No. 04-GO-001 Pursuant to 10 CFR 50.55a (a) (3) (i), Duke Energy Corporation proposes to use ASME Section XI Code Case N-613-1 as an alternative to the requirements of ASME Section XI, Figures IWB-2500-7 (a) and (b) 1989 Edition with no addenda. The proposed alternative provides an acceptable level of quality and safety.
I ASME Code Component (s) Affected:
Reactor Pressure Vessel (RPV) Nozzle-to-Vessel Welds.
ASME Section XI Class-1, Category B-D, Item Number: B3.90. There are eight Main Coolant Loop Nozzle-to-Vessel Welds at McGuire Unit 2, and Catawba Units 1 and 2; and six Main Coolant Loop Nozzle-to-Vessel Welds plus two Core Flood Nozzle-to-Vessel Welds at Oconee Unit 3.
II Applicable Code Edition and Addenda:
The ASME Section XI, 1989 Edition with no addenda is the applicable code of record for all units requesting relief. Catawba Unit I is in the second Inservice Inspection Interval, which started June 29, 1995 and ends June 29, 2005.
Catawba Unit 2 is in the second Inservice Inspection Interval, which started August 19, 1996 and ends August 19, 2006. Oconee Unit 3 is in the third Inservice Inspection Interval which started December 16, 1994 and ends December 16, 2004.
McGuire Unit 2 will be performing second interval RPV inspections. Specific relief has been granted to extend the 10 year interval 92 days beyond the code allowed 1 year interval extension to complete the Reactor Vessel inspections (Duke Relief Request No.03-004 approved July 20, 2004).
III Applicable Code Requirement:
ASME Section XI, Figures IWB-2500-7 (a) and (b) 1989 Edition with no addenda requires volumetric examination of a minimum volume of base material on each side of the weld equal to a distance of t,/2 (one half of the RPV shell thickness adjacent to the weld).
IV Reason for Request:
The required examination volume for the RPV nozzle-to-shell welds extends far beyond the weld into the base material and is unnecessarily large. The Section XI examination volume for the pressure retaining nozzle-to-vessel welds extends from the edge of the weld on the nozzle side and includes a substantial portion of the nozzle forging (inward) and the RPV upper shell course (outward). This large
04-GO-001 Page 2 of 3 volume causes a major increase in examination time with no resultant increase in quality or safety. The proposed alternative would define the examination volume as the weld and one-half inch of base material on each side of the widest portion of the weld. This base material examination volume was ultrasonically examined during preservice and subsequent inservice inspections. The examination results showed that there were no recordable indications outside of the volume defined in Code Case N-613-1, Figures 1 and 2. Relief is requested to use the examination volumes shown in Code Case N-613-1 Figures 1 and 2 in lieu of the examination volume requirements of ASME Section XI, Figures IWB-2500-7 (a) and (b), 1989 Edition with no addenda.
V Proposed Alternative and Basis for Use:
In lieu of the requirements of ASME Section XI, Figures IWB-2500-7 (a) and (b)
Duke Energy Corporation proposes to reduce the examination volume as shown in the attached Code Case N-613-1 and as represented in the attached illustrative vendor scan plans. The scan plans are derived from the vessel manufacturer design drawings which are the most dependable source for weld location, size and thickness. Code Case N-613-1, Figure 1 will be used for the RPV Main Coolant Loop Nozzle-to-Vessel Welds at McGuire Unit 2, Oconee Unit 3 and Catawba Units I and 2. Figure 2 will be used for Oconee Unit 3 Core Flood Nozzle-to-Vessel Welds. As added conservatism, the vendor scan plans have included an additional 0.5 inch of scan path to ensure that the boundaries of the weld are covered by the ultrasonic beams.
Stresses caused by welding are concentrated at the weld and heat affected zone.
Post weld heat treatment reduces these stresses and any residual stresses decrease as a function of the distance from the weld.
Operational stresses originate from internal pressure in the vessel and temperature changes occurring during transients. These stresses are limited by design to ensure that ASME Code stress limits are not exceeded. Additionally, a fatigue analysis is required by ASME Section III to ensure that flaws are unlikely to initiate during operation. Compared to the code limit of 1.0, the fatigue usage in the nozzle-to-shell weld regions are as follows:
Catawba Unit 1 0.1290 Catawba Unit 2 0.4472 McGuire Unit 2 0.113 Oconee Unit 3 0.634 Because stresses are reduced by post weld heat treatment and design requirements, the occurrence of flaws during service is unlikely.
04-GO-001 Page 3 of 3 During preceding ultrasonic examinations conducted in the first Interval at Catawba Units 1 and 2, the first Interval at McGuire Unit 2 and the first and second Intervals at Oconee Unit 3, no indications were found in the RPV Nozzle-to-Vessel Weld examination volume excluded by Code Case N-613-1. These examinations were conducted from the inside surface of the RPV and the inside diameter of the nozzle in accordance with ASME Section V, Article 4 and Regulatory Guide 1.150, Rev. 1. The previous ultrasonic examinations used an automated system to acquire, analyze and store data. The ultrasonic examinations schedule for the current interval will use personnel, -automated equipment and procedures qualified in accordance with ASME Section XI, Appendix VIII, Supplements 4, 6 and 7, 1995 Edition through the 1996 Addenda. Duke Energy Corporation is confident that satisfactory comparisons can be made between past and present examinations if necessary. Use of the proposed alternative will provide an acceptable level of quality and safety.
VI Duration of Proposed Alternative:
Duke Energy Corporation proposes to use Code Case N-613-1 to examine the RPV Nozzle-to-Vessel Welds during the 10-year RPV examinations scheduled for the fall 2004 outages at Catawba Unit 2 and Oconee Unit 3, the spring 2005 outages at McGuire Unit 2 and Catavba Unit 1.
VII Precedents:
This request for alternative is similar to the request approved for Hope Creek Generating Station (TAC NO. MB7839) on August 26, 2003. The request is also similar to those requested by Nuclear Management Company LLC for Monticello Nuclear Generating Plant, Docket 50-331, submitted on February 27, 2004 and Entergy Nuclear Northeast for Indian Point, Nuclear Generating Units 2 and 3 Dockets 50-247 and 50-286 respectively, submitted December 30, 2003.
Sponsored By t ha Date: a y Approved By: -Dat o4
CASE N-613-1 CASES OF ASME BOILER AND PRESSURE VESSEL, CODE Approval Date: August 20, 2002 See Numeric Index for expiration and any reaffirmation dates.
Case N-613-1 Ultrasonic Examination of Full Penetration Nozzles in Vessels, Examination Category B-D, Item No's. B3.10 and 113.90, Reactor Nozzle-To-Vessel Welds, Figs. IWB-2500-7(a), (b), and (c)
Section XI, Division 1 Inquiry: What alternatives to the examination volume requirements of Figs. IWB-2500-7(a), (b), and (c) arc permissible for ultrasonic examination of reactor-nozzle-to-vessel welds?
Reply: It is the opinion of the Committee that Cate-gory B-D nozzle-to-vessel wclds previously ultrasoni-cally examined using the examination volumes of Figs.
IWVB-2500-7(a), (b), and (c) may be examined using the reduced examination volume (A-B-C-D-E-F-G-Hi) of Figs. 1, 2. and 3.
1029 SUPP. 6 - NC
CASE (continued)
N-613-1 CASES OF ASME BOILER AND PRESSURE VESSEL CODE nl 1 --1 I\ I I \I tni, tn2 = nozzle wall thickness ts = shell (or head) thickness ri= nozzle inside corner radius A max.
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(1) Examination regions are identified for the purpose of differentiating the acceptance standards in IWB-3512.
(2) Examination volumes may be determined either by direct measurements on the component or by measurements based on design drawings.
FIG. 1 NOZZLE IN SHELL OR HEAD (Examination Zones in Barrel Type Nozzles Joined by Full Penetration Corner Welds) 1030 SUPP. 6- NC
CASE (continued)
N-613-1 CASES OF ASME BOILER AND PRESSURE VESSEL CODE
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Shell (or head) adjoining region C-D-E-F Attachment weld region B-C-F-G Nozzle cylinder region A- B- G- H Nozzle inside corner region M-N-O-P NOTES:
(1) Examination regions are identified for the purpose of differentiating the acceptance standards in IWB-3512.
(2) Examination volumes may be determined either by direct measurements on the component or by measurements based on design drawings.
FIG. 2 NOZZLE IN SHELL OR HEAD (Examination Zones in Flange Type Nozzles Joined by Full Penetration Butt Welds) 1031 SUPP. 6 - NC
CASE (continued)
N-613-1 CASES OF ASME BOILER AND PRESSURE VESSEL CODE elwt II I,
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Corner flaw EXAMINATION REGION (Note (111 EXAMINATION VOLUME [Note (2)1 Shell (or head) adjoining region C-D-E-F-G Attachment weld region B-C-G Nozzle cylinder region A-B-G-H Nozzle inside corner region M - N -O-P NOTES:
(1) Examination regions are identified for the purpose of differentiating the acceptance standards in IWB-3512.
(2) Examination volumes may be determined either by direct measurements on the component or by measurements based on design drawings.
FIG. 3 NOZZLE IN SHELL OR HEAD (Examination Zones in Set-On Type Nozzles Joined by Full Penetration Corner Welds) 1032 SUPP. 6 - NC
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