ML092370296
| ML092370296 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 08/19/2009 |
| From: | Jordan A Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 09-369, FOIA/PA-2011-0115 | |
| Download: ML092370296 (10) | |
Text
Dominion Nuclear Connecticut, Inc.
Millstone Power Station S4'Dominion-Rope Ferry Road Waterford, CT 06385 AUG 1 9 2009 U. S. Nuclear Regulatory Commission Serial No.09-369 Attention: Document Control Desk NLOS/WDC RO Washington, DC 20555 Docket No. 50-423 License No. NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 ALTERNATIVE REQUEST IR-3-13 FOR THE USE OF ALTERNATIVE DISSIMILAR METAL WELD EXAMINATION DEPTH-SIZING REQUIREMENTS FROM ASME CODE, SECTION XI Pursuant to 10 CFR 50.55a(a)(3)(i), Dominion Nuclear Connecticut, Inc. (DNC) hereby requests approval for the use of an alternative to the dissimilar metal weld examination depth-sizing requirements from ASME Code,Section XI, at Millstone Power Station Unit 3 (MPS3). This request supports the scheduled reactor vessel dissimilar metal nozzle-to-safe end weld ultrasonic test (UT) volumetric examinations to be performed during the MPS3 third 10-year inservice inspection (ISI) interval. Although there is no expectation that an identifiable indication exists which would require depth-sizing during these examinations, DNC is submitting this request as a contingency. DNC has determined that the proposed alternative in this request provides an acceptable level of quality and safety.
Alternative Request IR-3-13 and the proposed alternative for depth-sizing requirements are contained in Attachment 1 to this letter. DNC requests Nuclear Regulatory Commission review and approval of this request by March 1, 2010 to support the potential need for its use during the MPS3 spring 2010 refueling outage.
If you have any questions regarding this submittal, please contact Wanda D. Craft at (804) 273-4687.
Sincerely, A.J.
Site President - Millstone 9 0oq7 kttK
Serial No.09-369 Docket Nos. 50-423 Alternative Request IR-3-13 Page 2 of 2
Attachment:
1
- 1. Alternative Request IR-3-13 For the Use of Alternative Dissimilar Metal Weld Examination Depth-Sizing Requirements from ASME Code, Section Xl Commitments made in this letter: None cc: U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1415 Ms. C. J. Sanders Project Manager - Millstone Power Station U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop O-8B3 Rockville, MD 20852-2738 NRC Senior Resident Inspector (w/o attachments)
Millstone Power Station
Serial No.09-369 Alternative Request IR-3-13 Docket No. 50-423 ATTACHMENT 1 ALTERNATIVE REQUEST IR-3-13 FOR THE USE OF ALTERNATIVE DISSIMILAR METAL WELD EXAMINATION DEPTH-SIZING REQUIREMENTS FROM ASME CODE, SECTION XI DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3
Serial No.09-369 Alternative Request IR-3-13 Docket No. 50-423 Attachment 1 Page 1 of 7 ALTERNATIVE REQUEST IR-3-13 FOR THE USE OF ALTERNATIVE DISSIMILAR METAL WELD EXAMINATION DEPTH-SIZING REQUIREMENTS FROM ASME CODE, SECTION XI CONTENTS 1.0 ASME Code Components For Which the Alternative is Requested ........ ... 2 2.0 Applicable Code Edition and Addenda ............................................................ 3 3.0 Applicable Code Requirements For Which The Alternative is Requested ..... 3 4.0 Reason For The Request ........................................................................... 4 5.0 Proposed Alternatives and Basis For Use ....................................................... 5 6.0 Duration of the Proposed Alternative ........................................................ 6 7 .0 Precede nts .............................................................................................. .. 6 8 .0 R efe re nces .............................................................................................. .. 7 9 .0 C o n c lu s io n ................................................................................................. 1..... 7 TABLES Table 1 - Millstone Power Station Unit 3: Nozzle-to-Safe End Welds ................ 2 Table 2 - MPS3 Class 1 PWR Components Alloy 600/82/1826 ........................ 5
Serial No.09-369 Alternative Request IR-3-13 Docket No. 50-423 Attachment 1 Page 2 of 7 ALTERNATIVE REQUEST IR-3-13 FOR THE USE OF ALTERNATIVE DISSIMILAR METAL WELD EXAMINATION DEPTH-SIZING REQUIREMENTS FROM ASME CODE, SECTION XI ProposedAlternative In Accordance with 10 CFR 50.55a(a)(3)(i)
- Alternative ProvidesAcceptable Level of Quality and Safety -
1.0 ASME CODE COMPONENTS FOR WHICH THE ALTERNATIVE IS REQUESTED The reactor vessel dissimilar metal welds to be examined under this request are identified in Table 1 as follows:
Table 1 - Millstone Unit 3: Nozzle-to-Safe End Welds Internal Wall Weld Identification Number Diameter Thickness (inches) (inches) 301-121-A Inlet Nozzle To Safe End (RC Loop 3) 27.5 2.32 301-121-B Inlet Nozzle To Safe End (RC Loop 4) 27.5 2.32 301-121-C Inlet Nozzle To Safe End (RC Loop 1) 27.5 2.32 301-121-D Inlet Nozzle To Safe End (RC Loop 2) 27.5 2.32 302-121-A Outlet Nozzle To Safe End (RC Loop 3) 29 2.45 302-121-B Outlet Nozzle To Safe End (RC Loop 4) 29 2.45 302-121-C Outlet Nozzle To Safe End (RC Loop 1) 29 2.45 302-121-D Outlet Nozzle To Safe End (RC Loop 2) 29 2.45 Materials: Nozzle is SA508 Class 2, Safe End is SA 182 F316, and weld metal is Alloy 82/182 a) ASME Code Class:
American Society of Mechanical Engineers (ASME) Code Class 1, Dissimilar Metal Welds b) System:
Millstone Power Station Unit 3 (MPS3), Reactor Coolant System
Serial No.09-369 Alternative Request IR-3-13 Docket No. 50-423 Attachment 1 Page 3 of 7 c) Code Category:
Category B-P as required by Code Case N-722, Class 1 Pressurized Water Reactor (PWR) Components with augmented volumetric examination schedule requirements from Table 1 above and Alternative Request IR-3-10.
d) Item Nos.:
B15.90 - Hot Leg Nozzle Welds B15.95 - Cold Leg Nozzle Welds 2.0 APPLICABLE CODE EDITION AND ADDENDA MPS3 is in the third 10-year inservice inspection (ISI) interval which began on April 23, 2009, and is scheduled to end April 22, 2019. The ASME Code, Section Xl, 2004 Edition, Division 1, with No Addenda is the Code of record for the current third 10-year ISI interval program.
3.0 APPLICABLE CODE REQUIREMENTS FOR WHICH THE ALTERNATIVE IS REQUESTED The requirements for ultrasonic test (UT) examination of the reactor vessel dissimilar metal nozzle-to-safe end welds, which are performed once each 10-year ISI interval, are listed in ASME Section X1, Table IWB-2500-1, Examination Category B-F. In the second 10-year ISI interval, MPS3 performed volumetric UT examination of these welds using the risk-informed ISI program and the industry requirements in Electric Power Research Institute (EPRI), Materials Reliability Program (MRP) - 139, "Primary System Piping Butt Weld Inspection and Evaluation Guideline," (Reference 5) and its revisions.
In the third 10-year ISI interval, as part of the requirements mandated in 10 CFR 50.55a, Code Case N-722, "Additional Examinations for PWR Pressure Retaining Welds in Class 1 Components Fabricated With Alloy 600/82/182 Materials Section Xl, Division 1,"
(Reference 6), requires bare metal visual examinations of these welds on the outside surface at varying frequencies. For MPS3, bare metal visual examination of the welds is extremely difficult to perform -which is the subject of Alternative Request IR-3-10. In lieu of bare metal visual examination of the welds, MPS3 will volumetrically UT these welds.
These UT examinations will be performed on a more frequent schedule than the ASME Code and risk-informed ISI program requirements, as well as at a frequency that meets or exceeds the schedule shown in Table 2. These volumetric UT examinations will be performed in accordance with the performance demonstration requirements in ASME Code, Section Xl, 2001 Edition, with No Addenda under Appendix VIII, Supplement 10
Serial No.09-369 Alternative Request IR-3-13 Docket No. 50-423 Attachment 1 Page 4 of 7 with a demonstrated Root Mean Square (RMS) error of 0.125 inches, if depth-sizing is used.
4.0 REASON FOR THE REQUEST Dominion Nuclear Connecticut, Inc. (DNC) is submitting this request as a contingency for the use of alternatives to the reactor vessel nozzle examination depth-sizing requirements from ASME Code, Section Xl at MPS3, although there is no expectation that an identifiable indication exists which would require depth-sizing during these examinations. This request supports the reactor vessel nozzle-to-safe end weld volumetric examination schedule shown in Table 2 that will be performed on a more frequent schedule than once each 10-year interval in accordance with Alternative Request IR-3-1 0 that was included in the submittal of the MPS3 Third 10-year ISI Interval Program (Reference 7).
The ASME Code of record for the current MPS3 Third 10-Year ISI Interval Program is ASME Code, Section Xl, 2004 Edition, Division 1, with No Addenda (Reference 1). In accordance with the provisions of 10 CFR 50.55a(b)(xv), licensees that use later editions and addenda than the 2001 Edition of the ASME Code, shall use the 2001 Edition of Appendix VIII. Therefore, for MPS3, UT examination of the subject dissimilar metal nozzle-to-safe end welds is required to be implemented in accordance with the requirements of the ASME Code Section Xl, 2001 Edition, with No Addenda, Appendix VIII, Supplement 10 (Reference 2).
Code Case N-695, "Qualification Requirements for Dissimilar Metal Piping Welds, Section Xl Division 1" (Reference 3) may be used as an alternative to the ASME Section Xl, Appendix VIII, Supplement 10 requirements. Code Case N-695 is acceptable for use in Regulatory Guide 1.147, "Inservice Inspection Code Case Acceptability, ASME Section Xl, Division 1,"
Revision 15 (Reference 4), with no conditions required.
The specific Code requirements for this alternative request pertain to the depth-sizing qualification requirements for the performance demonstration of UT examination systems for dissimilar metal piping welds. Specifically, Code Case N-695 requires a demonstrated ability to meet the depth-sizing qualification requirements using a RMS error of 0.125 inches for the ultrasonic examination of dissimilar metal piping welds.
To date, an examination vendor for UT of the reactor vessel dissimilar metal nozzle-to-safe end welds shown in Table 1 has not been chosen. Although qualified for detection and length sizing on these welds, examination vendors have not met the established RMS error requirement for depth-sizing criteria (0.125 inches). DNC's examination vendor will be chosen from the available vendors that have demonstrated their ability to meet the depth-sizing qualification requirement with a RMS error of no greater than 0.224 inches instead of the required 0.125 inches.
Consequently, DNC proposes to use an alternative through wall depth-sizing criteria for volumetric UT examinations performed from the inside surface of ASME Code, Section
Serial No.09-369 Alternative Request IR-3-13 Docket No. 50-423 Attachment 1 Page 5 of 7 Xl, Appendix VIII, Supplement 10, components. UT examination of these components will be performed according to the schedule in Table 2 below.
Table 2: MPS3 Class 1 PWR Components Alloy 6001821182 Reproduced From Alternative Request IR-3-10 Deferral of First Successive Inspection Parts Examination Examination Acceptance Inspection Inspection To end of Item No. Examined Requirements Method Standards Interval Intervals Interval B15.90 Hot leg All 4 Hot leg Volumetric(a'b) IR-3-10 Every Same as for Not nozzle-to- nozzle-to safe other 1 st interval permissible pipe end welds refueling connections outagelcl B15.95 Cold leg All 4 Cold leg Volumetric(a'b) IR-3-10 Every 3 rd Same as for Not Nozzle-to nozzle-to safe refueling 1 st interval permissible pipe end welds outage"'
connections Notes related to examination of hot leg nozzle to pipe connection (B15.90) and cold leg nozzle to pipe connection (B1 5.95):
(a) UT will be performed from the inside diameter of these welds in lieu of the Visual, VE.
(b) UT examinations will meet the appropriate supplement of Section Xl, Appendix VIII of the ASME Boiler and Pressure Vessel Code. The required weld volume shall be as shown on Fig. IWB-2500-8(c), of the ASME Code, Section Xl, 2004 Edition, with No Addenda.
(c) UT will be performed every other refueling outage. These welds were last examined in the spring of 2007 (3R11) outage and will be due in the spring 2010 (3R13) outage based on the analysis in Attachment 2 of Request IR-3-10, which supports UT approximately every 36 months.
(d) UT will be performed every 3 rd refueling outage. They were last examined in the spring of 2007 (3R1 1) and will be due in the fall 2011 (3R14) outage based on the analysis in Attachment 2 of Request IR-3-10, which supports UT approximately every 54 months.
5.0 PROPOSED ALTERNATIVES AND BASIS FOR USE The volumetric examinations are to be conducted in accordance with Code Case N-695 as an alternative to ASME Code,Section XI, 2001 Edition with No Addenda, Appendix VIII, Supplement 10. The specific Code requirement for which an alternative is requested
Serial No.09-369 Alternative Request IR-3-13 Docket No. 50-423 Attachment 1 Page 6 of 7 pertains to the depth-sizing qualification requirement for the performance demonstration of UT examination systems for dissimilar metal piping welds.
Code Case N-695 - "Qualification Requirements for Dissimilar Metal Piping Welds,"
Section Xl, Division 1 Code Case Requirement: Examination procedures, equipment, and personnel are qualified for depth-sizing when the RMS error of the flaw depth measurements, as compared to the true flaw depths, do not exceed 0.125 inches (3 mm).
Proposed Alternative: To use Code Case N-695 with a modified demonstrated maximum RMS error of 0.224 inches instead of the 0.125 inches as specified in the Code Case.
DNC proposes to use the maximum RMS error values that have been demonstrated and approved previously for other licensees. In the event an indication is detected that requires depth-sizing, the difference between the required RMS error and the demonstrated maximum RMS error of the selected vendor will be added to the measured through-wall extent for comparison with applicable acceptance criteria.
Addition of the difference in allowable depth-sizing tolerance from that actually demonstrated to the estimated flaw depths measured will compensate for the variance in the measured depth.
Because the UT examinations will be performed over the 10-year ISI interval more frequently than required by the ASME Code, DNC is proposing that this request be applied for the entire interval to alleviate the need to submit this request each time a different vendor is used. By using the maximum demonstrated RMS error values, this request will not change the acceptable level of quality and safety related to these examinations as they are performed at MPS3.
6.0 DURATION OF THE PROPOSED ALTERNATIVE The proposed alternative to the ASME Code is applicable for the remainder of the MPS3 third 10-year ISI interval.
7.0 PRECEDENTS There have been multiple requests submitted and approved regarding the use of similar alternatives to the requirement for depth-sizing contained in Section XI, Appendix VIII and Code Case N-695. Alternative Request (RR-1 1-20) has been approved for use at the V.C. Summer Station in NRC letter dated February 3, 2004 (ADAMS Accession No. ML040340450). In addition, Alternative Request IR-2-42 was approved for MPS3 for
Serial No.09-369 Alternative Request IR-3-13 Docket No. 50-423 Attachment 1 Page 7 of 7 use during the second 10-year ISI interval in NRC letter dated May 1, 2007 (ADAMS Accession No. ML070740586).
8.0 REFERENCES
- 1. 2004 Edition, ASME Code, Section Xl, "Rules for Inservice Inspection of Nuclear Power Plant Components," Division 1, with No Addenda.
- 2. 2001 Edition, ASME Code, Section Xl, Division 1, with No Addenda, Appendix VIII, Supplement 10.
- 3. Code Case N-695, "Qualification Requirements for Dissimilar Metal Piping Welds,"
Section Xl, Division 1.
- 4. NRC Regulatory Guide 1.147, "Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1," Revision 15.
139, "Primary System Piping Butt Weld Inspection and Evaluation Guideline,"
and its revisions.
- 6. Code Case N-722, "Additional Examinations for PWR Pressure Retaining Welds in Class 1 Components Fabricated With Alloy 600/82/182 Materials," Section Xl, Division 1.
- 7. DNC letter to NRC Document Control Desk, "Millstone Unit 3 - Third 10-Year Interval Inservice Inspection Program and Associated Proposed Alternatives and Relief Requests," dated April 28, 2009 (ADAMS Accession No. ML091310666).
9.0 CONCLUSION
DNC has determined that the alternative in this request will result in an acceptable level of quality and safety, pursuant to the provisions of 10 CFR 50.55a(a)(3)(i), because the proposed alternative assures that the subject welds will be fully examined by procedures, personnel and equipment qualified by demonstration in all aspects except depth-sizing.
The proposed addition of the difference between the ASME required RMS error value and the vendor demonstrated RMS error value to any flaw that is required to be depth sized, compensates for the potential variation and likewise assures an acceptable level of quality and safety.