BW070052, Inservice Inspection Program Relief Request I2R-49
| ML071910315 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 07/10/2007 |
| From: | Coutu T Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BW070052 | |
| Download: ML071910315 (6) | |
Text
10 CFR 50.55a July 10, 2007 BW070052 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Facility Operating License Nos, NPF-72 and NPF-77 NRC Docket Nos. 50-456 and 50-457
Subject:
Inservice Inspection Program Relief Request 12R-49 In accordance with 10 CFR 50.55a, Codes and standards, paragraph (a)(3)(i), Exelon Generation Company, LLC (EGC), is requesting relief from the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, on the basis that alternative methods will provide an acceptable level of quality and safety.
Specifically, relief is requested to use the qualification requirements for weld examinations conducted from the inside piping surface contained in ASME Code Case N-696 along with the vendors Root Mean Squared (RMS) error achieved under the Performance Demonstration Initiative (PDI) at the EPRI NDE Center. The details of the request for relief are enclosed.
EGC requests approval of this request by October 2007 in order to support the second ten-year Inservice Inspection for Braidwood Station Units 1 and 2. If there are any questions or comments, please contact Mr. David Gulloff, Regulatory Assurance Manager, at (815) 417-2800.
Respectfully, Ic~J~,~/; /
Thomas Coutu Site Vice President Braidwood Station
Enclosure:
Braidwood Station Relief Request l2R-49
Enclosure Braidwood Station Relief Request l2R-49
lSl Program Plan Braidwood Station Units 1 & 2, Second Interval 10 CFR 50~55aRELIEF REQUEST I2R-49 Revision 0 (Page 1 of 4)
Request for Relief in Accordance with 10 CFR 50.55a(a)(3)(i)
Alternative Requirements to ASME Section XI Appendix VIII (Supplements 2 and 10)
Examinations of Class 1 Pressure Retaining Welds Conducted from the Inside Surface 1.
ASME CODE COMPONENT(S) AFFECTED:
Code Class:
1 Examination Categories:
Category R-A (Risk Informed ISI)
Item Numbers:
R1.15 (Nozzle-to-Safe End)
Ri.20 (Safe End-to-Pipe, Safe End-to-Elbow)
Component Numbers:
See Table 1 Drawing Numbers:
See Table 1 2.
APPLICABLE CODE EDITION AND ADDENDA:
The current inservice inspection program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 1989 Edition with no Addenda. Ultrasonic examination of applicable Class 1 and 2 components is governed by Appendix VIII, Performance Demonstration for Ultrasonic Examination Systems, of the ASME Code, Section Xl, 1995 Edition with the 1996 Addenda.
3.
APPLICABLE CODE REQUIREMENTS:
The examination of Class 1 and 2 piping welds are required to be performed using procedures, personnel, and equipment qualified to the criteria of the ASME Code,Section XI, 1995 Edition 1996 Addenda, Appendix VIII, Supplement 10, Qualification Requirements for Dissimilar Metal Pipe Welds and Supplement 2, Qualification Requirements for Wrought Austenitic Piping Welds for the examination of Item Ri.15 nozzle-to-safe end welds and Item Ri.20 austenitic safe end welds, respectively.
Paragraph 3.2, Sizing Acceptance Criteria, subparagraph (b) of Supplement 10 states that the examination procedures, equipment, and personnel are qualified for depth-sizing when the RMS (root mean square) error of the flaw depth measurements, as compared to the true flaw depths, is less than or equal to 0.125-inch (3.2mm).
Paragraph 3.2, Sizing Acceptance Criteria of Supplement 2 also requires an RMS error less than or equal to 0.125-inch in order for examination procedures, equipment, and personnel to be qualified for depth-sizing.
Code Case N-695, Qualification Requirements for Dissimilar Metal Piping Welds,Section XI, Division 1 provides alternative requirements to Appendix VIII, Supplement 10 and is unconditionally approved for use through Regulatory Guide 1.147, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, Revision 14.
ISI Program Plan Braidwood Station Units 1 & 2, Second Interval 10 CFR 50.55a RELIEF REQUEST I2R-49 Revision 0 (Page 2 of 4)
Paragraph 3.3(c) of Code Case N-695 states 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 in, (3 mm).
Code Case N-696, Qualification Requirements for Appendix VIII Piping Examinations Conducted From the Inside Surface,Section XI, Division 1 provides alternative requirements to Appendix VIII Supplements 2, 3, and 10 examinations conducted from the inside surface. Code Case N-696 is currently not approved in the current Revision of Regulatory Guide 1.147 (i.e.,
Revision 14), but is listed unconditionally for use in the proposed Draft Regulatory Guide DG-1134 Table 1 (ADAMS MLO61 210404). Note that Supplement 3, Qualification Requirements for Ferritic Piping Welds, is not applicable to the welds referenced under this relief request.
Paragraph 3.3(d) of Code Case N-696 states Supplement 2 or Supplement 3 examination procedures, equipment, and personnel are qualified for depth-sizing when the flaw depths estimated by ultrasonics, as compared to true depths, do not exceed 0.125 in. (3 mm) RMS, when they are combined with a successful Supplement 10 qualification.
4.
REASON FOR THE REQUEST:
Exelon Generation Company, LLC. (EGC) is performing volumetric examinations of all nozzle-to-safe end welds dissimilar metal (DM) welds and a select number of adjacent safe end-to-pipe or safe end-to-elbow welds (austenitic welds) from the inside diameter (ID) surface during the upcoming ten-year ISI inspections. If only the DM weld is examined, EGC will use the NRC approved requirements of Code Case N-695 for qualification requirements. However, if both welds (DM weld and the adjacent austenitic weld) are examined, EGC proposes using Code Case N-696 to perform a combined qualification.
EGC also proposes using an alternative RMS error depth-sizing requirement as compared to the 0.125-inch RMS error value stated in Code Cases N-695 and N-696. EGC contacted the Electric Power Research Institute (EPRI) NDE Center on June 15, 2007 and confirmed that no vendor has successfully demonstrated compliance with the Code required 0.125-inch RMS value for qualification tests for examinations conducted from the ID surface (for either stand alone Supplement 10 or combined Supplement 2 and 10 qualifications).
EGC has verified through the EPRI NDE Center that the examination vendor selected to perform the scheduled examinations at Braidwood Station, has achieved a 0.245-inch RMS error for the combined Supplement 2 and 10 qualification (as addressed in Code Case N-656) and a 0.189-inch RMS error (as addressed in Code Case N-695) for the stand alone Supplement 10 qualification.
5.
PROPOSED ALTERNATIVE AND BASIS FOR USE:
Pursuant to 10 CFR 50.55a(a)(3)(i), relief is requested for an alternative requirement that will provide an acceptable level of quality and safety.
When examinations of both the DM weld and an adjacent austenitic weld are performed, EGC proposes to use the qualification requirements in Code Case N-696 to perform a combined Supplement 2 and 10 qualifications. The difference between the examination vendors achieved RMS error of 0.245-inch and the Code Case N-696 required 0.125-inch RMS error (total of 0.120-inches) will be applied to actual flaw depths when depth-sizing of indications is required.
ISI Program Plan Braidwood Station Units 1 & 2, Second Interval 10 CFR 50.55a RELIEF REQUEST 12R-49 Revision 0 (Page 3 of 4)
For examinations limited to DM welds (adjacent austenitic weld is not being examined), EGC proposes to apply the difference between the examination vendors achieved RMS error of 0.189-inch and the Code Case N-695 required 0.125-inch RMS error (total of 0.064-inches) to actual flaw depths when depth-sizing of indications is required.
Applying the difference between the required RMS error and the achieved RMS error to the actual flaw being sized will ensure a conservative bounding flaw depth value for dissimilar metal and austenitic welds examined at Braidwood Station.
6, DURATION OF PROPOSED ALTERNATIVE:
This relief request will be implemented during the remainder of the Braidwood Station Second Ten-Year inservice inspection interval, currently scheduled to end July 28, 2008 (Unit 1) and October 16, 2008 (Unit 2).
7.
PRECEDENTS:
Relief requests approving the examination vendor selected by Braidwood Station have been approved for a number of sites (i.e., Byron, V. C. Summer, Callaway, Diablo Canyon, et al).
Southern Nuclear, using the same examination vendor as Braidwood Station, has submitted and was granted approval of a similar relief request under the following:
Evangelos C. Marinos (NRR) letter to D. E. Grissette (Southern Nuclear Operating),
dated September 29, 2006, Joseph M. Farley Nuclear Plant, Unit 1, and Vogtle Electric Generating Plant, Units 1 and 2 Evaluation of Relief Request ISl-GEN-ALT-06-02 (TAC Nos. MD2482, MD2483, and MD2484), ADAMS ML062770359.
8.
ATTACHMENTS None
ISI Program Plan Braidwood Station Units 1 & 2, Second Interval 10 CFR 50.55a RELIEF REQUEST 12R-49 Revision 0 (Page 4 of 4)
TABLE 1: Applicable Components at Braidwood Station WELD NUMBER DESCRIPTION R WN
~
FORMER ASME XI ITEM NUMBER CURRENT RI-ISI ITEM NUMBER Unit 1 1RV-Oi-022 RPV Nozzle-to-Safe End Hot Leg, Loop C 1RV-0i 85.10 Ri.15 1 RV-01 -030 RPV Safe End-to-Pipe Hot Leg, Loop C 1 RV-0i B9.i 1 Ri 20 1RV-01 -023 RPV Nozzle-to-Safe End Cold Leg, Loop C 1RV-O1 85.10 Ri.15 1 RV-O1 -031 RPV Safe End-to-Elbow Cold Leg, Loop C 1 RV-O1 89.11 Ri.20 1RV-Oi-024 RPV Nozzle-to-Safe End Cold Leg, Loop 0 1RV-0i 85.10 Ri.15 1RV-O1-032 RPV Safe End-to-Elbow Cold Leg, Loop D 1RV-Oi 89.11 Ri.20 1RV-Oi-025 RPV Nozzle-to-Safe End Hot Leg, Loop D 1RV-O1 85.10 Ri.15 1 RV-0i -033 RPV Safe End-to-Pipe Hot Leg, Loop 0 1 RV-O1 B9.i 1 Ri.20 1RV-01-026 RPV Nozzle-to-Safe End Hot Leg, Loop A 1RV-Oi 85.10 AilS 1RV-01-034 RPV Safe End-to-Pipe Hot Leg, Loop A 1RV-0i 89.11 R1.20 1 RV-Oi -027 RPV Nozzle-to-Safe End Cold Leg, Loop A 1 RV-Oi 85.10 Ri.15 iRV-Oi-035 RPV Safe End-to-Elbow Cold Leg, Loop A 1RV-Oi 89.11 R1,20 1RV-Oi-028 RPV Nozzle-to-Safe End Cold Leg, Loop B 1RV-Oi 85.10 AilS 1RV-01-036 RPV Safe End-to-Elbow Cold Leg, Loop B 1RV-01 89.11 Ri.20 1RV-Oi-029 RPV Nozzle-to-Safe End Hot Leg, Loop B 1RV-Oi 85.10 Ri,iS 1RV-01-037 RPV Safe End-to-Pipe Hot Leg, Loop B 1RV-Oi 89.11 Ri,20 Unit 2 2RV-Oi -022 RPV Nozzle-to-Safe End Hot Leg, Loop D 2RV-Oi B5.iO R1.iS 2RV-Oi -030 RPV Safe End-to-Pipe Hot Leg, Loop D 2RV-Oi 89.11 Ri.20 2RV-Oi -023 RPV Nozzle-to-Safe End Cold Leg, Loop D 2RV-Oi 85.10 Ri.i5 2RV-Oi-03i RPV Safe End-to-Elbow Cold Leg, Loop D 2RV-01 89.11 Ri.20 2RV-Oi-024 RPV Nozzle-to-Safe End Cold Leg, Loop C 2RV-Oi 85.10 Ri.i5 2RV-Oi -032 RPV Safe End-to-Elbow Cold Leg, Loop C 2RV-Oi 89.11 Ri.20 2RV-Oi -025 RPV Nozzle-to-Safe End Hot Leg, Loop C 2RV-Oi B5.iO Ai.i5 2RV-Oi-033 RPV Safe End-to-Pipe Hot Leg, Loop C 2RV-Oi B9.i 1 Ri.20 2RV-Oi-026 RPV Nozzle-to-Safe End Hot Leg, Loop B 2RV-Oi 85.10 AilS 2RV-0l-034 RPV Safe End-to-Pipe Hot Leg, Loop B 2RV-Oi B9.ii Ri.20 2RV-0i -027 RPV Nozzle-to-Safe End Cold Leg, Loop B 2RV-0i 85.10 Ri.15 2AV-Oi-035 RPV Safe End-to-Elbow Cold Leg, Loop B 2AV-Oi 89.11 Ri 20 2RV-Oi-028 RPV Nozzle-to-Safe End Cold Leg, Loop A 2RV-Oi 85.10 Ri.i5 2RV-Oi-036 RPV Safe End-to-Elbow Cold Leg, Loop A 2RV-Oi 89.11 Ri.20 2AV-Oi-029 RPV Nozzle-to-Safe End Hot Leg, Loop A 2RV-Oi 85.10 Ri.i5 2RV-Oi-037 RPV Safe End-to-Pipe Hot Leg, Loop A 2RV-0l 89.11 Ri.20