ML101230179

Relief Request I3R-03 for Examination of Structural Weld Overlays

ML101230179
Person / Time
Site:	Braidwood
Issue date:	05/10/2010
From:	Shawn Campbell Plant Licensing Branch III
To:	Pardee C Exelon Nuclear
David, Marshall - DORL 415-1547
References
I3R-03, TAC ME2198, TAC ME2199
Download: ML101230179 (12)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 10, 2010 Mr. Charles G. Pardee President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

BRAIDWOOD STATION, UNITS 1 AND 2 - RELIEF REQUEST 13R-03 FOR EXAMINATION OF STRUCTURAL WELD OVERLAYS (TAC NOS. ME2198 AND ME2199)

Dear Mr. Pardee:

By letter to the Nuclear Regulatory Commission (NRC), dated September 4,2009 (Agencywide Documents Access and Management System Accession No. ML092510267), Exelon Generation Company, LLC (the licensee), submitted Relief Request (RR) 13R-03 for relief from certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), for the third 10-year inservice inspection (lSI) interval for Braidwood Station (Braidwood), Units 1 and 2. The third 10-year lSI interval for Braidwood is currently scheduled to end on July 28, 2018, for Unit 1 and on October 16, 2018, for Unit 2. Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR), 50.55a(a)(3)(i), the licensee proposed an alternative to the requirements in ASME Code,Section XI, Appendix VIII, Supplement 11, "Qualification Requirements for Full Structural Overlaid Wrought Austenitic Piping Welds." In lieu of the ASME Code requirements, the licensee proposed using the qualification process as administered by the Electric Power Research Institute's Performance Demonstration Initiative (PDI) program for weld overlay qualification.

The NRC staff has reviewed the licensee's submittal and determined that, in accordance with 10 CFR 50.55a(a)(3)(i), use of the PDI program for implementation of ASME Code,Section XI, Appendix VIII, Supplement 11 provides an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the alternative proposed in RR 13R-03 is authorized for the third 10-year lSI interval at Braidwood, Units 1 and 2. All other ASME Code,Section XI requirements for which relief was not specifically requested and approved remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector. The NRC staff's safety evaluation is enclosed.

C. Pardee -2 Please contact Mr. Marshall David at (301) 415-1547 if you have any questions on this action.

Stephen J. Campbell, Chief Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-456 and 50-457

Enclosure:

Safety Evaluation 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 NO. 13R-03 EXELON GENERATION COMPANY, LLC.

BRAIDWOOD STATION. UNITS 1 AND 2 DOCKET NOS. STN 50-456 AND 50-457

1.0 INTRODUCTION

By letter to the Nuclear Regulatory Commission (the Commission, NRC), dated September 4, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML092510267), Exelon Generation Company, LLC (the licensee), submitted Relief Request (RR) 13R-03 for relief from certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) at the Braidwood Station, Units 1 and 2. Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR),

50.55a(a)(3)(i), the licensee proposed an alternative to the requirements in ASME Code,Section XI, Appendix VIII, Supplement 11, "Qualification Requirements for Full Structural Overlaid Wrought Austenitic Piping Welds." In lieu of the ASME Code requirements, the licensee proposed using the qualification process as administered by the Electric Power Research Institute (EPRI), Performance Demonstration Initiative (PDI) program for weld overlay qualification. The request is for the third 1O-year inservice inspection (lSI) interval, which is currently scheduled to end on July 28, 2018, for Unit 1 and on October 16, 2018, for Unit 2.

The NRC staff has reviewed and evaluated the information provided by the licensee in its submittal. The results of the NRC staff's review are presented in the remainder of this safety evaluation.

2.0 REGULATORY EVALUATION

lSI of ASME Code Class 1, 2, and 3 components is to be performed in accordance with ASME Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components,"

applicable edition and 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 at 10 CFR 50.55a(a)(3) state in part that alternatives to the requirements of paragraph (g) may be used when authorized by the NRC staff, if the applicant demonstrates that: (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.

-2 Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1,2, and 3 components (including supports) will meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in 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 10-year lSI 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 regulations at 10 CFR 50.55a(g)(4)(iv) state that inservice examination of components and system pressure tests may meet the requirements set forth in subsequent editions and addenda that are incorporated by reference in paragraph 10 CFR 50.55a(b), subject to the limitations and modification listed in 10 CFR 50.55a(b) and subject to Commission approval. Portions of editions or addenda may be used provided that all related requirements of the respective editions or addenda are met.

The code of record for the third 10-year lSI interval at the Braidwood Station, Units 1 and 2, is the 2001 Edition through 2003 Addenda of the ASME Code,Section XI.

3.0 TECHNICAL EVALUATION

3.1 ASME Code Components Affected

Code Class: 1 Examination Category: R-A

Description:

Appendix VIII, Supplement 11 examination of Structural Weld Overlays (SWOLS) of the Pressurizer Surge, Spray, Safety, and Relief Nozzles, Dissimilar Metal Welds including the SWOLs of the Adjacent Safe-End to Pipe, Reducer and Elbow Welds on Pressurizer Surge, Spray, Safety and Relief Nozzles

- COMPONENT IDENTIFICATION I Unit 1 Pressurizer 1RY01S Weld Overlays NOZZLE NOZZLE-TO-SAFE ITEM SIZE ADJACENT CONFIGURATION ITEM#

END WELD # WELD h;e

. Spray 1PZR-01-SE-01 1PZR-01-SE-05 R1.11 R1.15 R1.11 14" 4"

1RC-05-01 1RC-16-01 Safe-end to Pipe 6"x4" Reducer to R1.11 R1.11 R1.15 Safe-end

!Relief 1PZR-01-SE-06 R1.15 6" 1RC-35-01 Safe-end to Cut R1.20 45° Elbow I Safety A 1PZR-O 1-SE-02 R1.15 6" 1RC-32-01 Safe-end to Cut R1.20 90° Elbow Safety B 1PZR-O 1-SE-03 R1.15 6" 1RC-32-07 Safe-end to Cut R1.20 90° Elbow Safety C 1PZR-01-SE-04 R1.15 6" 1RC-32-13 I Safe-end to Cut R1.20 I 90° Elbow

- 3 COMPONENT IDENTIFICATION Unit 2 Pressurizer 2RY01S Weld Overlays NOZZLE NOZZLE-TO-SAFE ITEM SIZE ADJACENT CONFIGURATION ITEM #

END WELD # WELD Surge 2PZR-01-SE-01 R1.11 14" 2RC-05-01 Safe-end to Pipe R1.11 R1.15 Spray 2PZR-01-SE-05 R1.11 4" 2RC-16-01 6"x4" Reducer to R1.11 R1.15 Safe-end Relief 2PZR-01-SE-06 R1.15 6" 2RC-35-01 Safe-end to Cut R1.20 45° Elbow Safety A 2PZR-01-SE-02 R1.15 6" 2RC-32-01 Safe-end to Cut R1.20 90° Elbow I Safety B 2PZR-01-SE-03 R1.15 6" 2RC-32-07 Safe-end to Cut R1.20 90° Elbow Safety C 2PZR-01-SE-04 R1.15 6" 2RC-32-13 Safe-end to Cut R1.20 I 90° Elbow Note: Item numbers reflect the risk-informed classification per ASME Code Case N-578-1.

R1.11: Elements subject to thermal fatigue.

R1.15: Elements subject to primary water stress corrosion cracking.

R1.20: Elements not subject to a damage mechanism.

3.2 Applicable Code The code of record for the third 10-year lSI interval at Braidwood Station, Units 1 and 2, is the 2001 Edition through 2003 Addenda of the ASME Code,Section XI. The ultrasonic testing (UT) examination must be performed using personnel, procedures, and equipment qualified in accordance with the 2001 Edition, No Addenda, of the ASME Code,Section XI, Appendix VIII, Supplement 11, "Qualification Requirements For Full Structural Overlaid Wrought Austenitic Piping Welds." The specific paragraphs in Supplement 11 affected by this RR are:

1.1(b), 1.1(d)(1), 1.1{e){1), 1.1(e){2), 1.1(e)(2)(a){1), 1.1(e)(2){a){2), 1.1{e)(2)(a)(3),

1.1(e )(2){b )(1), 1.1(e)(2){b )(2), 1.1 (e)(2){b )(3), 1.1(f)(1), 1.1 (f)(3), 1.1 (f){4), 2.0, 2.1, 2.2( d), 2.3, 3.1, 3.2( a), and 3.2(b).

3.3 Licensee's Proposed Alternative Pursuant to 10 CFR 50.55a(a){3)(i), the licensee requests relief from the qualification requirements of ASME Code,Section XI, Appendix VIII, Supplement 11 and proposes instead to use the ultrasonic qualification program for weld overlay inspections developed and administered though the EPRI POI program.

3.4 Licensee's Basis for Proposed Alternative and NRC Staff Evaluation U.S. nuclear utilities created the POI program to implement performance demonstration requirements contained in Appendix VIII of Section XI of the ASME Code. To this end, POI has developed a program for qualifying equipment, procedures, and personnel for examinations of

- 4 weld overlays in accordance with the UT criteria of Appendix VIII, Supplement 11. Prior to the Supplement 11 program, EPRI maintained a performance demonstration program for weld overlay qualification under the Tri-party Agreement among NRC, EPRI, and the Boiling-Water Reactor Owners Group (BWROG), "Coordination Plan for NRC/EPRIIBWROG Training and Qualification Activities of NOE [Nondestructive Examination] Personnel," July 3, 1984 (Reference 1). Instead of having two programs with similar objectives, the NRC staff recognized the POI program for weld overlay qualifications as an acceptable alternative to the Tri-party Agreement (Reference 2).

The POI program is routinely assessed by the NRC staff for consistency with the current ASME Code and proposed changes. The POI program does not fully comport with the existing requirements of Supplement 11. POI presented the differences at public meetings in which the NRC participated (for example, References 3 and 4). The differences are in flaw locations within test specimens and fabricated flaw tolerances. The changes in flaw location permitted using test specimens from the Tri-party Agreement, and the changes in fabricated flaw tolerances provide UT acoustic responses similar to the responses associated with intergranular stress-corrosion cracking (IGSCC). Based on the discussions at these public meetings, the NRC staff determined that the POI program provides an acceptable level of quality and safety.

Pursuant to 10 CFR 50.55a(a)(3)(i), the licensee requested relief to use the EPRI POI program for implementation of Appendix VIII, Supplement 11 requirements. Specifically, relief was requested from Supplement 11, Paragraphs 1.1(b), 1.1(d)(1), 1.1(e)(1), 1.1 (e)(2) , 11(e)(2)(a)(1),

1.1(e)(2)(a)(2), 1.1(e)(2)(a)(3), 1.1(e)(2)(b)(1), 1.1(e)(2)(b)(2), 1.1(e)(2)(b)(3), 1.1(f)(1), 1.1(f)(3),

1.1(f)(4), 2.0, 2.1, 2.2(d), 2.3, 3.1, 3.2(a) and 3.2(b). The proposed alternative will be implemented through use of the EPRI POI program weld overlay examination qualification requirements.

The licensee's basis for the proposed alternative and the NRC staff's evaluation of the differences identified in the POI program vs. Supplement 11 follow.

Paragraph 1.1 (b) of Supplement 11 states limitations to the maximum thickness for which a procedure may be qualified. The ASME Code states that, "The specimen set must include at least one specimen with an overlay thickness within minus 0.1 O-inch to plus 0.25-inch of the maximum nominal overlay thickness for which the procedure is applicable." The ASME Code requirement addresses the specimen thickness tolerance for a single specimen set, but is confusing when multiple specimen sets are used. The POI proposed alternative states that, "The specimen set shall include specimens with overlays not thicker than 0.1 O-inch more than the minimum thickness, nor thinner than 0.25-inch of the maximum nominal overlay thickness for which the examination procedure is applicable." The proposed alternative provides clarification on the application of the tolerance. The tolerance is unchanged for a single specimen set; however, the proposed alternative clarifies the tolerance for multiple specimen sets by providing tolerances for both the minimum and maximum thicknesses. The proposed wording eliminates confusion while maintaining the intent of the overlay thickness tolerance. Therefore, the NRC staff finds that this POI program alternative maintains the intent of the Supplement 11 requirements and is acceptable.

Paragraph 1.1 (d)(1) of Supplement 11 requires that all base metal flaws be cracks. POI determined that certain Supplement 11 requirements pertaining to location and size of cracks

- 5 would be extremely difficult to achieve. For example, flaw implantation requires excavating a volume of base material to allow a pre-cracked coupon to be welded into this area. This process would add weld material to an area of the specimen that typically consists of only base material, and could potentially make ultrasonic examination more difficult and not representative of actual field conditions. In an effort to satisfy the requirements, POI developed a process for fabricating flaws that exhibit crack-like reflective characteristics. Instead of all flaws being cracks, as required by Paragraph 1.1 (d)(1), the POI program for weld overlays contains at least 70 percent cracks with the remainder being fabricated flaws exhibiting crack-like reflective characteristics.

The fabricated flaws are semi-elliptical with tip widths of less than 0.002 inches. The licensee provided further information describing a revision to the POI program alternative to clarify when real cracks, as opposed to fabricated flaws, will be used; "POI limits flaws in cases where implantation of cracks produces spurious reflectors that are uncharacteristic of actual flaws."

The NRC staff has reviewed the flaw fabrication process, compared the reflective characteristics between actual cracks and POI-fabricated flaws, and found that the fabricated flaws for this application provide assurance that the POI program meets the intent of the Supplement 11 requirement. Therefore, the NRC staff finds that the proposed alternative to the Supplement 11 requirement is acceptable.

Paragraph 1.1 (e)(1) of Supplement 11 requires that at least 20 percent but not less than 40 percent of the flaws shall be oriented within +/-20 degrees of the axial direction (of the piping test specimen).

Flaws contained in the original base metal heat-affected zone satisfy this requirement; however, POI excludes axial fabrication flaws in the weld overlay material. POI has concluded that axial flaws in the overlay material are improbable because the overlay filler material is applied in the circumferential direction (parallel to the girth weld); therefore, fabrication anomalies would also be expected to have major dimensions in the circumferential direction. The NRC staff finds that this approach to implantation of fabrication flaws is reasonable for meeting the intent of the Supplement 11 requirement. Therefore, the NRC staff concludes that POI's application of flaws oriented in the axial direction is acceptable.

Paragraph 1.1 (e)(1) of Supplement 11 also requires that the rules of IWA-3300 shall be used to determine whether closely spaced flaws should be treated as single or multiple flaws. POI treats each flaw as an individual flaw and not as part of a system of closely spaced flaws. POI controls the flaws going into a test specimen set such that the flaws are free of interfering reflections from adjacent flaws. In some cases this permits flaws to be spaced closer than what is allowed for classification as a multiple set of flaws by IWA-3300, thus potentially making the performance demonstration more challenging than the existing requirement. Therefore, the NRC staff*

concludes that POI's application for closely spaced flaws is acceptable.

Paragraph 1.1 (e)(2) of Supplement 11 requires that specimens be divided into base metal and overlay grading units. The POI program adds clarification with the addition of the word "fabrication" and ensures that flaw identification will not be masked by other flaws with the addition of, "Flaws shall not interfere with ultrasonic detection or characterization of other flaws."

POI's alternative provides clarification and assurance that the flaws are identified. Therefore, the NRC staff finds that the POI alternative to the Supplement 11 requirement is acceptable.

Paragraph 1.1 (e)(2)(a)(1) of Supplement 11 requires that a base grading unit shall include at least 3 inches of the length of the overlaid weld, and the base grading unit includes the outer 25 percent of the overlaid weld and base metal on both sides. The POI program reduced the

- 6 criteria to 1 inch of the length of the overlaid weld and eliminated from the grading unit the need to include both sides of the weld. The proposed change permits the POI program to continue using test specimens from the existing weld overlay program which have flaws on both sides of the welds. These test specimens have been used successfully for testing the proficiency of personnel for over 16 years. The weld overlay qualification is designed to be a near-side (relative to the weld) examination, and it is improbable that a candidate would detect a flaw on the opposite side of the weld due to the sound attenuation and re-direction caused by the weld microstructure. However, the presence of flaws on both sides of the original weld (outside the POI grading unit), may actually provide a more challenging examination, as candidates must determine the relevancy of these flaws, if detected. The NRC staff has determined that POI's use of the 1 inch length of the overlaid weld base grading unit and elimination from the grading unit of the need to include both sides of the weld, as described in the POI program alternative, is an acceptable alternative to the Supplement 11 requirements. Therefore, the NRC staff finds the proposed alternative acceptable.

Paragraph 1.1 (e)(2)(a)(2) of Supplement 11 requires, when base metal cracking penetrates into the overlay material, that a portion of the base grading unit shall not be used as part of the overlay grading unit. The NRC staff finds that the POI program adjusts for the changes in Paragraph 1.1 (e)(2)(a)(2) and conservatively states that, when base metal flaws penetrate into the overlay material, no portion of it shall be used as part of the overlay fabrication grading unit.

The NRC staff finds that the POI program also provided clarification by the addition of the term "flaws" for "cracks" and the addition of "fabrication" to "overlay grading unit." The NRC staff concludes that the POI program alternative provides clarification and conservatism and, therefore, is acceptable.

Paragraph 1.1 (e)(2)(a)(3) of Supplement 11 requires that for unflawed base grading units, at least 1 inch of unflawed overlaid weld and base metal shall exist on either side of the base grading unit. This is to minimize the number of false identifications of extraneous reflectors.

The POI program stipulates that unflawed overlaid weld and base metal exists on all sides of the grading unit and flawed grading units must be free of interfering reflections from adjacent flaws which addresses the same concerns as the ASME Code. Hence, the NRC staff concludes that POI's application of the variable flaw-free area adjacent to the grading unit meets the intent of the Supplement 11 requirements and is, therefore, acceptable.

Paragraph 1.1 (e)(2)(b)(1) of Supplement 11 requires that an overlay grading unit shall include the overlay material and the base metal-to-overlay interface of at least 6 square inches. The overlay grading unit shall be rectangular, with minimum dimensions of 2 inches. The POI program reduces the base metal-to-overlay interface to at least 1 inch (in lieu of a minimum of 2 inches) and eliminates the minimum rectangular dimension. This change is necessary to allow use of existing examination specimens that were fabricated in order to meet NRC Generic Letter 88-01, "NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping," January 25, 1988 (which refers to the Tri-party Agreement). This change may be more challenging to meet than that of the ASME Code because of the variability associated with the shape of the grading unit.

Therefore, the NRC staff concludes that POI's application of the grading unit is an acceptable alternative to the Supplement 11 requirements and is acceptable.

Paragraph 1.1 (e)(2)(b)(2) of Supplement 11 requires that unflawed overlay grading units shall be surrounded by unflawed overlay material and unflawed base metal-to-overlay interface for at

-7 least 1 inch around its entire perimeter. The POI program redefines the area by noting that unflawed overlay fabrication grading units shall be separated by at least 1 inch of unflawed material at both ends and sufficient area on both sides to preclude interfering reflections from adjacent flaws. The NRC staff determined that the relaxation in the required area on the sides of the specimens, while still ensuring no interfering reflections, may provide a more challenging demonstration than required by the ASME Code because of the possibility of having a parallel flaw on the opposite side of the weld. Therefore, the NRC staff concludes that POI's application is an acceptable alternative to the Supplement 11 requirements.

Paragraph 1.1(e)(2)(b)(3) of Supplement 11 requirements are retained in the POI program. In addition, the POI program requires that initial procedure qualification contain three times the number of flaws required for a personal qualification. To qualify new values of essential variables, the equivalent of at least one personal qualification is required. The NRC staff concludes that POI's additions enhance the ASME Code requirements and are, therefore, acceptable because they provide for more stringent qualification criteria.

Paragraph 1.1(f)(1) of Supplement 11 requirements are retained in the POI program, with the clarification change of the term "flaws" for "cracks." In addition, the POI program includes the requirements that sizing sets shall contain a distribution of flaw dimensions to verify sizing capabilities. The POI program also requires that initial procedure qualification contain three times the number of flaws required for a personal qualification. To qualify new values of essential variables, the equivalent of at least one personal qualification is required. The NRC staff concludes that POI's additions enhance the ASME Code requirements and are, therefore, acceptable because they provide more stringent qualification criteria.

Paragraphs 1.1 (f)(3) and 1.1 (f)( 4) of Supplement 11 requirements are clarified by the POI program by replacing the term "cracking" with "flaws" because of the use of alternative flaw mechanisms. The NRC staff concludes that this clarification in the POI program meets the intent of the ASME Code requirements and is acceptable.

Paragraph 2.0 of Supplement 11 is silent on performance demonstrations for the weld metal and overlay fabrication. The POI program addresses the two performance demonstrations by specifying that they may be performed separately. The POI program adds clarity to the testing criteria without changing the requirement. Therefore, the NRC staff concludes that POI's clarification is an enhancement to the ASME Code requirement and is acceptable.

Paragraphs 2.1 and 2.2(d) of Supplement 11 requirements are clarified by the POI program by the addition of the terms "metal" and "fabrication." These terms were added to clarify the description of the grading units present in a specimen. "Metal" was added to "base" to read "base metal," and "fabrication" was added to "overlay" to read "overlay fabrication." The NRC staff determined that the clarifications provide acceptable classification of the terms they are enhancing. Therefore, the NRC staff concludes that the POI program meets the intent of the ASME Code requirements and is acceptable.

Paragraph 2.3 of Supplement 11 requires that, for depth sizing tests, 80 percent of the flaws shall be sized at a specific location on the surface of the specimen identified to the candidate.

This requires detection and sizing tests to be performed, separately. The POI revised the weld overlay program to allow sizing to be conducted either in conjunction with, or separately from,

- 8 the flaw detection test. If performed in conjunction with detection and the detected flaws do not meet the Supplement 11 range criteria, additional specimens will be presented to the candidate with the regions containing flaws identified. Each candidate will be required to determine the maximum depth of the flaw in each region. For separate sizing tests, the regions of interest will also be identified and the maximum depth and length of each flaw in the region will similarly be determined. In addition, POI stated that grading units are not applicable to sizing tests, and that each sizing region will be large enough to contain the target flaw, but small enough such that candidates will not attempt to size a different flaw. The NRC staff has determined that the above clarification provides a basis for implementing sizing tests in a systematic, consistent manner that meets the intent of Supplement 11. Therefore, the NRC staff concludes that POI's method is acceptable.

Paragraph 3.1 of Supplement 11 requires that examination procedures, equipment, and personnel (as a complete ultrasonic system) are qualified for detection or sizing of flaws, as applicable, when certain criteria are met. The POI program allows procedure qualification to be performed separately from personnel and equipment qualification. Historical data indicate that, jf ultrasonic detection or sizing procedures are thoroughly tested, personnel and equipment using those procedures have a higher probability of successfully passing a qualification test. In an effort to increase this passing rate, POI has elected to perform procedure qualifications separately in order to assess and modify essential variables that may affect overall system capabilities. For a procedure to be qualified, the POI program requires three times as many flaws to be detected (or sized) as shown in Supplement 11 for the entire ultrasonic system. The personnel and equipment are still required to meet the Supplement 11 requirement. Therefore, the POI program criteria exceed the ASME Code requirements for personnel, procedures, and equipment qualifications. The NRC staff concludes that the POI program criteria are acceptable.

Paragraph 3.2(a) of Supplement 11 refers to term the "cracking" in the base metal and flaws within the same acceptance criteria. The POI program changed the term from cracking to flaws for consistency in the acceptance criteria and uniformity within the proposed alternative. The NRC staff concludes that POI's change adds clarity and meets the intent of the ASME Code requirements, thus the change is acceptable.

Paragraph 3.2(b) of Supplement 11 requires that all extensions of base metal cracking into the overlay material by at least 0.1 O-inch are reported as being intrusions into the overlay material.

The POI program omits this criterion because of the difficulty in actually fabricating a flaw with a 0.10-inch minimum extension into the overlay, while still knowing the true state of the flaw dimensions. However, the POI program requires that the crack depth be sized to the tolerance specified in the ASIVIE Code, which is 0.125-inches. Since the ASME Code tolerance is close to the 0.1O-inch value of Paragraph 3.2(b), any crack extending beyond 0.1 O-inches into the overlay material would be identified as such from the characterized dimensions. The NRC staff has determined that reporting of an extension in the overlay material is redundant for performance demonstration testing because of the flaw sizing tolerance. Therefore, the NRC staff concludes that POI's omission of highlighting a crack extending beyond 0.1 O-inches into the overlay material is acceptable.

- 9

4.0 CONCLUSION

The NRC staff has reviewed the licensee's submittal and determined that, in accordance with 10 CFR 50.55a(a)(3)(i), use of the PDI program for implementation of ASME Code,Section XI, Appendix VIII, Supplement 11 provides an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the alternative proposed in RR 13R-03 is authorized for the third 10-year lSI interval at Braidwood Station, Units 1 and 2, which is currently scheduled to end on July 28,2018, for Unit 1, and on October 16,2018, for Unit 2.

All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in this RR remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.

5.0 REFERENCES

1. Tri-party Agreement among NRC, EPRI, and the BWROG, "Coordination Plan for NRC/EPRI/BWROG Training and Qualification Activities of NDE Personnel," July 3, 1984 (Legacy ADAMS Accession No. 8407090122).

2. Letterfrom William H. Bateman to Michael Bratton, "Weld Overlay Performance Demonstration Administered by PDI as an Alternative for Generic Letter 88-01 Recommendations," January 15, 2002 (ADAMS Accession No. ML020160532).

3. Memorandum from Donald G. Naujock to Terence Chan, "Summary of Public Meeting Held January 31 - February 2,2001, with PDI Representatives," March 22,2001 (ADAMS Accession No. ML010940402).

4. Memorandum from Donald G. Naujock to Terence Chan, "Summary of Public Meeting Held June 12 through June 14, 2001, with PDI Representatives," November 29,2001 (ADAMS Accession No. ML013330156).

Principal Contributor: Carol Nove, NRR Date: May 10, 2010

C. Pardee -2 Please contact Mr. Marshall David at (301) 415-1547 if you have any questions on this action.

Sincerely, IRA!

Stephen J. Campbell, Chief Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-456 and 50-457

Enclosure:

Safety Evaluation cc w/encl: Distribution via Listserv DISTRIBUTION:

PUBLIC LPL3-2 R1F RidsNrrDorlLpl3-2 Resource RidsNrrPMBraidwood Resource RidsNrrLATHarris Resource CNove, NRR RidsAcrsAcnw_MailCTR Resource RidsNrrDciCpnb Resource RidsNrrDorlDpr Resource RidsRgn3MailCenter Resource RidsOgcRp Resource ADAMS ACCESSION NO.: ML101230179 *SE memo date NRR-028 E LPL3-2/PM LPL3-2/LA DCI/CPNB/BC* LPL3-2/BC NAME MDavid THarris TChan SCampbell DATE 5/6/10 5/5/10 12/18109 5/10/10 OFFICIAL RECORD COPY