ML20135C778
| ML20135C778 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 02/25/1997 |
| From: | Tulon T COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9703040287 | |
| Download: ML20135C778 (8) | |
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Commonwealth Illiwn Company liraidwo(xl Gencrating Station Route 01,ihm Hi liraces ille, IL 60 607 Axil 9 Tel8144 W 2801 l
l February 25,1997 United States Nuclear Regulatory Conunission Attention: Document Control Desk Washington, D.C. 20555-0001 l
Subject:
Braidwood Nuclear Power Station, Units I and 2, Response to Request for Additional Information Regarding First 10-year ISI, Facility Operating Licenses NPF-72 and NPF-77, NRC Docket Nos. 50-456 and 50-457 i
References:
1.
Robert A. Capra (USNRC) letter to D. L. Farrar (Comed), Safety i
Evaluation of the Insenice Inspection Program Relief Requests Nos. NR-20, NR-21, NR-22 for Braidwood Station Units I and 2 (TAC Nos. M 92120, M92121) dated September 1, 1995.
2.
- 11. G. Stanley (Comed) letter to Document Control Desk (USNRC), Resision 4 of the Insenice Inspection Plan for i
Braidwood Station Units 1 and 2 dated October 8,1996.
3.
George F. Dick (USRNRC) letter to Irene M. Johnson (Comed),
Request for Additional Information Regarding First 10-Year Insenice inspection Program - Braidwood Station, dated February 11,1997.
Ladies and Gentlemen:
Commonwealth Edison Company's (Comed's) Braidwood Nuclear Power Station, Units I and 2 (Braidwood), performs insenice inspections MSI) in accordance with Section XI of the 1983 Edition of the American Society of Mechanical Engineers Boiler ant' Pressure Vessel Code through the Summer 1983 Addenda (ASME Code), as required by Title 10, Code of Federal P.gulations, Part 50, Section 55a, Paragraph f, Subparagraph 3 [10 CFR 50.55a(f)(3)], except where alternatives be been authorized or relief has been requested and granted by the United States Nuclear Regulatory Commie:Jon (USNRC).
The information requested in Reference 3 is provided in Attachment I and Table A. All relief request updates for NR-29 are reflected in Attachment 2.
Comed respectfully requests USNRC continued expedited resiew and approval of Relief Request NR-29, such that these requirements can be implemented during the upcoming Unit I and Unit 2,1997 outages. These outages represent the last outages in the first ISI interval for Braidwood Station. Please address any comments or questions regarding this matter to Ms. Patricia A. Boyle, at (815)458-2801 extension 2519.
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Dohment Control Desk Pace 2 Sincerely,
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Timf y J. Tulon Staf nManager Br idwood Generating Station Attachments (3)
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cc:
A. B. Beach. Regional Administrator - Rill G. F. Dick, Jr., Braidwood Project Manager - NRR C. Phillips, Senior Resident inspector - Braidwood Office of Nuclear Facility Safety - IDNS Michael T. Anderson, INEL Research Center p
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ATTACHMENT 1 NRC RAIItem A.
Based on the resiew of Relief Request NR-29, it appears that the licensee is requesting relief from Code volumetric examination technique and procedural requirements (i.e. ASME Section XI, ASME Section V, Article 4, and Regulatory Guide 1.150). As an alternative, the licensee proposes to implement a performance based procedure. It is generally agreed that qualification by demonstration would provide a basis to conclude that the flaw detection capabilities of a performance based procedure would be at least equal to that of past examinations. However, the qualification of volumetric examination techniques in accordance with the Performance Demonstration Initiative (PDI),
is currently under resiew by the StaK. As such, performance based qualifications do not preclude the requirement to satisfy the Code of record for a plant or other commitments that the licensee may have made.
Response
The staff has determined that licensees must state the specific paragraph of the Regulations under which each proposed alternative or request for reliefis submitted:
1 10 CFR 50.55a(a)(3)(i) "The proposed alternatives would provide an acceptable level of quality and safety, or" 10 CFR 50.55a(a)(3)(ii) " Compliance with the specified requirements of this section would result in hardship or unusual difliculty without a compensating increase in the level of quality and safety."
10 CFR 50.55a(g)(5)(iii) "If the licensee has determined that conformance with certain code requirements is impractical for its facility, the licensee shall notify the Commission and submit, as specified in 10 CFR 50.4, information to support the determinations."
Braidwood is requesting relief under paragraph 10 CFR 50.55a(a)(3)(i). The proposed alternative would provide an acceptable level of quality and safety. Relief Request NR 29 is updated to reflect the paragraph of the Regulations.
NRC RAI Item B.1.
From initial resiew of the relief, the staff cannot determine the specific part(s) of the Code or regulations for which i
reliefis being requested. As such, please describe the differences between the requirements associated with the Code of record and commitments for the licensce's plant, and the performance based ultrasonic examination procedure being implemented to satisfy the subject examinations.
Remonhe j
i Braidwood is requesting relief from the Section XI, Summer 1983 Addenda, Paragraph IWA-2232 requirements which requires these examinations to be conducted in accordance with Article 4 of Section V, Summer 1983 Addenda and as l
amended by Section XI. The attached Table A identifies the specific applicable Section V and XI requirements and the proposed correspmling alternative Performance Demonstration Initiative (PDI) technique. The above information is j
incorporated into Relief Request NR-29, which is provided in Attachment 2.
1 NRC RAI Item B.2.
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Provide the bases to conclude that the proposed alternative will meet or exceed current code requirements.
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1 ReYponse I
Framatome Technologies' (FTI) performance-based UT procedure for reactor vessel shell welds has been successfully i
demonstrated in accordance with the Performance Demonstration initiative (PDI) in December 1995. The PD1 program was developed consistent with the objectives of ASME Section XI,1992 Edition with the 1993 Addenda, Appendix Vill. Because the performance-based demonstration requires the inspection equipment, procedures, and i
examiners to be tested on flawed specimen representing materials and configurations similar to those found in actual plant conditions, perfonnance-based UT techniques provide a higher degree of reliability for detection and l
characterization of flaw when compared to the conventional amplitude-based UT techniques which is currently
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required by ASME Section XI,1989 Edition and earlier code editions and addendas. The NRC Staff has acknowledged the improvement achieved by perfonnance-based UT techniques in the recently issued proposed Generic Letter 96-XX: Effectiveness of Ultrasonic Testing Systems In Inservice Inspection Programs (Federal Register Notice of December 31,1996; 61 FR 69120). Additionally, the NRC Staff has assessed the PDI program activities and found that PD1 has established and executed a well-planned and effective program to test UT equipment, procedures, and examiners on selected ponions of Appendix VIII, which include reactor vessel inspection technique. This l
I assessment is documented in a letter from J. Strosnider (NRC) to B. Sheffel (PDI) dated March 6,1996 and referenced l
in the above mentioned proposed Generic Letter. This information has been added to Relief Request NR-29, which is l
provided in Attachment 2.
NRC RAI Item B.3.
l Verify that scanning of welds will be performed from both sides of the weld on the same surface, where feasible.
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Renmnse I
it is the Braidwood's intent to use the technique that was qualified by the Performance Demonstration Initiative (PDI) at the EPRI NDE Center to meet the intent of Appendix VIII of the 1992 Edition with 1993 Addenda. This qualified technique consisted of scanning the examination volume, weld and base metal, as below:
1 (1)
For flaw detection, the examination volume will be scanned in two directions, one perpendicular and one parallel to the weld axis. The examination volume is scanned from one direction such that all the examination angles pass through the entire examination volume of interest for each transducer. If full coverage is limited, scarming from both directions will be performed when coverage can be maximized.
l (2)
For flaw characterization (or flaw sizing), the examination will be conducted from two opposing directions, in the direction perpendicular to the plane of the flaw, when feasible.
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ATTACIIMENT 2 l
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l RELIEF REOUEST NR-29 COMPONENT IDENTIFICATION Code Class (es):
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Reference:
IWB-2500-1 Examination Categories:
B-A Item Numbers:
Bl.11, Bl.21, Bl.30
==
Description:==
Alternative rules for the Inservice Inspection of Reactor Vessel Circumferential Shell Welds, Lower Head Circumferential Weld and Shell to Flange Weld.
Component Number (s):
Unit I Welds:
1RV-01-003, IRV-01-004, IRV-01-005, iRV-024)01,1RV-024)02 Unit 2 Welds:
2 RV-01 -003, 2RV-014X)4, 2RV-01 -005, 2RV-024)01, 2 RV-024X)2 CODE REOUIREMENT Subsection IWB, Table IWB-2500-1, Examination Category B-A, items Bl.11, Bl.21 and Bl.30 requires volumetric examination be performed on the above Reactor Vessel Welds. These volumetric examinations are to be performed in accordance with IWA-2232. IWA-2232 states that the inspections "shall be conducted in accordance with Article 4 of Section V", and amended by Section XI. Braidwood is currently committed to the ASME Section XI 1983 Edition with Summer 1983 Addenda of Section V and XI.
BASIS FOR REl.lEF Reliefis requested pursuant to the provision of 10 CFR 50.55a(a)(3)(i), the proposed alternative would provide an acceptable level of quality and safety.
Braidwood is iequesting relief from the Section XI,1983 Edition with Summer 1983 Addenda, Paragraph IWA-2232 requirements which requires these examinations to be conducted in accordance with Article 4 of Section V,1983 Edition with Summer 1983 Addenda and as amended by Section XI. The attached Table A identifies the specific applicable Section V and XI requirements and the proposed corresponding alternative Performance Demonstration Initiative (PDI) technique.
1 The Electric Utility industry has developed a program to qualify ultrasonic inspection techniques. This program, Performance Demonstration Initiative (PDI), is designed to meet the intent of Appendix Vill of the ASME Code,Section XI,1992 Edition with 1993 Addenda. This program, PDI, used a variety of test blocks to evaluate transducer 1
designs, scanning requirements and flaw sizing techniques.
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Braidwood has contracted with Framatome Technologies (FTI) to use the URSULA manipulator to perform the 10 Year Ultrasonic (UT) Reactor Vessel inspections. It is the Braidwood's intent to use the FTl technique qualified in December 1995 to the PDI Program at the EPRI NDE Center that meets the intent of Appendix Vll! of the 1992 Edition with 1993 Addenda. This FTl qualified PD1 technique consists of scanning the examination volume, weld and base metal, as follows-chefidssteycorresp:199797016 doe i
RELIEF REOUEST NR-29 (cont.)
i (1)
For flaw detection, the examination volume will be scanned in two directions, one perpendicular and one
. parallel to the weld axis. The examination volume is scanned from one direction such that all the examination angles pass through the entire examination volume ofinterest for each transducer. If full coverage is limited, scanning from both directions will be performed when coverage can be maximized.
(2)
For flaw characterization (or flaw sizing), the examination will be conducted from two opposing directions, in the direction perpendicular to the plane of the flaw, when feasible.
Performance-based UT techniques provide a higher degree of reliability for detection and characterization of flaws when compared to the conventional amplitude-based UT techniques that are currently required by ASME Section XI, 1989 Edition and earlier code editions and addendas. The performance-based demonstration requires the inspection l
equipment, procedures, and exeminers to be tested on flawed specimen representing materials and configurations similar to those found in actual plant conditions. The NRC Staff has acknowledged the improvement achieved by j
performance-based UT techniques in the recently issued proposed Generic Letter 96-XX: EfTectiveness of Ultrasome Testing Systems in Inservice Inspection Programs (Federal Register Notice of December 31,1996; 61 FR 69120).
Additionally, the NRC StafT has assessed the PDI program activities and found that PD1 has established and executed a well-planned and efTective program to test UT equipment, procedures, and examincts on selected portions of Appendix VIII, which include reactor vessel inspection technique. This assessment is documented in a letter from J. Strosnider (NRC) to B. Sheffel (PDI) dated March 6,1996 and referenced in the above mentioned proposed Generic Letter.
PROPOSED ALTERNATE PROVISIONS Braidwood proposes to use FTI's underwater volumetric inspection techniques to inspect the reactor vessel Circumferential shell welds, lower head Circumferential weld and shell to flange weld. FTI's inspection techniques
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have been demonstrated and qualified to the PD1 Program which meets the intent of the rules of Appendix Vill of the ASME Code,Section XI,1992 Edition with 1993 Addenda. These techniques will be used in place of the currently required Section XI,1983 Edition with Summer 1983 Addenda, techniques.
APPLICABLE TIME PERIOD This relief request will be required for the First Ten Year inspection Interval.
APPROVAL STATUS i
Pending NRC resiew.
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Table A COMPARISON OF RPV SIIELL WELD EXAMINATION TECIINIQUES Description (Code reference)
Standard Section V, XI, Reg, Guide 1.150 Procedure FTl PDI/ Appendix Vill Qualified Procedure
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Examination Angles Four transducers required to perform the detection scans 0*,
Three transducers 45' S,45' L, and 70* L.
(Section V, T-441.1 and T-441.6) 45' Shear wave (S),. and 60* S for Code examination and a 45' L and 70* L to examine the inner 10% of thickness.
70* longitudinal wave (L) for clad to base metal interface, 45' S and 45' L to examine beyond 10% thickness.
Reg Guide 1.150 requirement. Additional transducers used for sizing unacceptable flaws.
Calibrations 0*,45* S, and 60* S calibrated on each ASME calibration One calibration standard designed to establish a calibrated time (Section V, T-432 and T-434) stamlard based on examination thickness range, usually 9.0" base and calibration sensitivity for each transducer using 1/16" or and 5.0" bhicks. De 70* is calibrated on one calibration I/8' diameter side drilled holes. One calibration stamlard, three standard using I/16' or 1/8" diameter side drilled holes.
calibrations.
Three calibration bhicks, ten calibrations.
Scan Direction To the extent practical the examination volume is scanned in The examination volume, weld and base metal, is scanned in two (Section V, T-441.4, T-441.5 and T-four directions, two perpendicular and two parallel to the directions, one perpendicular and one parallel to the weld axis.
l 441.6) weld axis. The weld metal is scanned with two angles from De examination volume is scanned from one direction such that all two opposing directions and the base metal is scanned with the examination angles pass through the entire examination volume two angles but not necessarily from two opposing directions.
of interest for each transducer. If full coverage is limited, semning from both directions will be performed when coverage can be maximized. Sizing is performed from two opposing directions, when feasible.
Scanning Sensitivity Section XI, +6dB beyond 25% of thidness. Reg. Guide Minimum +20dB at the maximum thickness of the applicable (Section V T-425) 1.150, + 14dB for the first 25%.
examination volume.
Recording Level Section XI,50% DAC (Code required reflectors). Reg.
70* L - 20% DAC, (1/16" dia. SDH cal.)
(Section V, T-441.3.2.8)
Guide '.150,20% DAC for the first 25% of material 45* S - 20% DAC, (1/8" dia. SDH cal.)
thickness.
45' L - 10% DAC, (li8" dia. SDH cal.)
Sean Index Minimum 50% overlap.
33% overlap for detection and 73% overlap for sizing.
(Section V, T-425 and amended by t
paragraph IWA-2232)
Flaw Sizing Amplitude based sizing at 50% DAC. Tip diffraction as Tip diffraction techniques using the same transducers and (Section V, T-441.8) option for flaws determined to exceed IWB-3500 acceptance calibrations used for the initial detection scans. FTl qualified the standards based on amplitude sizing. Requires additional examination procedure for Supplement 4 and 6 sizing using the transducers, calibrations, and scanning. Beam spread same transducers and calibrations used for detection. In addition, calculations are required.
FTl qualified a forward scatter time-of-flight eliffraction (TOFD) technique for the Supplement 4 examination volume as a supplemental technique. Beam spread calculations are not perfomied for these techniques.
Scan Speed (Section V T-425)
Up to 6.0" per second.
Up to 9.0* per second.
Proedure Qualification Transducers capable of detecting the calibration reflectors in Perfomiance denmnstration using cracks. Qualified on 12.0" thick the applicable calibration bkick.
samples containing a 12.0" wide band of manual clad 0.44" thick.
Data Analyst Certified Level 11 per Code of record (Section XI, Summer A minimum of a certified Level II (Section XI, Summer 1983 1983 Addenda and 1980 SNT-TC-1 A).
Addenda and 1980 SNT-TC-1 A) and qualified by perfomiance demonstration using flawed samples.
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