ML041000516

Relief Requests ISI-27 Through ISI-31 Pertaining to Implementation of ASME Section XI Appendix Viii Requirements. (Tacs. MC0478-MC0482)

ML041000516
Person / Time
Site:	Callaway
Issue date:	04/07/2004
From:	Fields M NRC/NRR/DLPM/LPD4
To:	Randolph G Union Electric Co
Fields M B ,NRR/DLPM,415-3062
References
TAC MC0478, TAC MC0479, TAC MC0480, TAC MC0481, TAC MC0482
Download: ML041000516 (30)

Text

April 7, 2004 Mr. Garry L. Randolph Vice President and Chief Nuclear Officer Union Electric Company Post Office Box 620 Fulton, MO 65251

SUBJECT:

CALLAWAY PLANT, UNIT 1 - RELIEF REQUESTS ISI-27 THROUGH ISI-31 PERTAINING TO IMPLEMENTATION OF ASME SECTION XI APPENDIX VIII REQUIREMENTS (TAC NOS. MC0478 THROUGH MC0482, RESPECTIVELY)

Dear Mr. Randolph:

By letter dated August 14, 2003 (ULNRC-04879), you requested relief from certain requirements related to the reactor vessel upper shell to flange ultrasonic qualification criteria and the examination volume requirements of the reactor pressure vessel nozzle-to-vessel welds in Section XI, on inservice inspection, of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (the ASME Code) at Callaway Plant, Unit 1 (Callaway). The five relief requests, ISI-27 through ISI-31, pertaining to the implementation of ASME,Section XI, Appendix VIII requirements, are for the second 10-year inservice inspection interval at Callaway.

The staff has evaluated the five relief requests against the requirements of Section XI of the 1989 Edition of the ASME Code, which is the applicable ASME Code for Callaway. Based on the enclosed safety evaluation, the alternatives to the requirements in Section XI of the ASME Code in RRs ISI-27 through ISI-31 provide an acceptable level of quality and safety. Based on this, pursuant to 10 CFR 50.55a(a)(3)(i), the Commission authorizes the proposed alternatives in RRs ISI-27 through ISI-31 for the remainder of the second 10-year ISI interval at Callaway Sincerely,

/RA by Mel Fields for/

Stephen Dembek, Chief, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-483

Enclosure:

Safety Evaluation cc w/encl: See next page

April 7, 2004 Mr. Garry L. Randolph Vice President and Chief Nuclear Officer Union Electric Company Post Office Box 620 Fulton, MO 65251

SUBJECT:

CALLAWAY PLANT, UNIT 1 - RELIEF REQUESTS ISI-27 THROUGH ISI-31 PERTAINING TO IMPLEMENTATION OF ASME SECTION XI APPENDIX VIII REQUIREMENTS (TAC NOS. MC0478 THROUGH MC0482, RESPECTIVELY)

Dear Mr. Randolph:

By the letter dated August 14, 2003 (ULNRC-04879), you requested relief from certain requirements related to the reactor vessel upper shell to flange ultrasonic qualification criteria and the examination volume requirements of the reactor pressure vessel nozzle-to-vessel welds in Section XI, on inservice inspection, of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (the ASME Code) at Callaway Plant, Unit 1 (Callaway). The five relief requests, ISI-27 through ISI-31, pertaining to the implementation of ASME,Section XI, Appendix VIII requirements, are for the second 10-year inservice inspection interval at Callaway.

The staff has evaluated the five relief request against the requirements of Section XI of the 1989 Edition of the ASME Code, which is the applicable ASME Code for Callaway. Based on the enclosed safety evaluation, the alternatives to the requirements in Section XI of the ASME Code in RRs ISI-27 through ISI-31 provide an acceptable level of quality and safety. Based on this, pursuant to 10 CFR 50.55a(a)(3)(i), the Commission authorizes the proposed alternatives in RRs ISI-27 through ISI-31 for the remainder of the second 10-year ISI interval at Callaway Sincerely,

/RA by Mel Fields for/

Stephen Dembek, Chief, Section 2 Project Directorate IV Division of Licensing Project Management Office of Nuclear Reactor Regulation DISTRIBUTION:

Docket No. 50-483 PUBLIC PDIV-2 Reading

Enclosure:

Safety Evaluation RidsNrrDlpmPdiv (HBerkow)

RidsNrrPMJDonohew cc w/encl: See next page RidsNrrLaEPeyton RidsOgcRp RidsACRSACNWMailCenter RidsRegion4MailCenter (D. Graves)

TChan

• See EMCB Memo dated 03/25/04 AKeim ACCESSION NO.: ML041000516 NRR-106 OFFICE PDIV-2/PM PDIV-2/LA EMCB/SC OGC nlo PDIV-2/SC NAME JDonohew EPeyton TChan* RHoefling MFields for SDembek DATE 3/26/04 3/26/04 03/25/2004 4/6/04 4-7-04 DOCUMENT NAME: C:\MyFiles\Copies\Callaway RelReq-Mc0478.wpd OFFICIAL RECORD COPY

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO RELIEF REQUESTS ISI-27 THROUGH ISI-31 UNION ELECTRIC COMPANY CALLAWAY PLANT, UNIT 1 DOCKET NO. 50-483

1.0 INTRODUCTION

By letter dated August 14, 2003, Union Electric Company (the licensee) requested relief from certain requirements related to the reactor vessel upper shell to flange ultrasonic qualification criteria and the examination volume requirements of the reactor pressure vessel nozzle-to-vessel welds in Section XI, "Rules for In-Service Inspection of Nuclear Power Plant Components," of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (the ASME Code) at Callaway Plant, Unit 1 (Callaway). The five relief requests (RRs),

ISI-27 through ISI-31, pertaining to the implementation of ASME,Section XI, Appendix VIII requirements, are for the second 10-year inservice inspection (ISI) interval at Callaway. The relief is requested from (1) the 1989 Edition to ASME Code,Section XI for selected requirements of nozzle-to-vessel weld volume, and (2) the 1995 Edition including the 1996 Addenda of ASME Code,Section XI, Appendix VIII for requirements on vessel ultrasonic qualification criteria and examination coverage.

2.0 REGULATORY EVALUATION

In the Commission's regulations, 10 CFR 50.55a(g) specifies that inservice inspection (ISI) of nuclear power plant components shall be performed in accordance with the requirements of the ASME Code,Section XI, except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). Section 50.55a(a)(3) states in part that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if the licensee 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. Section 50.55a(g)(5)(iii) states that 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, to support the determinations.

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, "Rules for Inservice Inspection of Nuclear Power Plant Components," 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 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) twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The ISI code of record for Callaway Plant second 10-year ISI interval is the 1989 Edition. The components (including supports) may meet the requirements set forth in subsequent editions and addenda of the ASME Code incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein and subject to Commission approval.

3.0 TECHNICAL EVALUATION

FOR RRs NOS. ISI-27 THROUGH ISI-31 In its application, the licensee requested relief from certain ASME Code,Section XI, requirements in the following five RRs: ISI-27 through ISI-31. These five RRs are addressed in Sections 3.1 through 3.5, respectively, in this safety evaluation.

3.1 RR ISI-27 3.1.1 Components for Which Relief is Requested The applicable reactor pressure vessel (RPV) piping welds in RR ISI-27 are Class 1 pressure retaining piping welds examined from the inside surface using procedures, personnel, and equipment qualified to ASME Code,Section XI, Appendix VIII, Supplements 2 and 10 criteria. These applicable welds are listed in the licensee's application and given in Table 1

[Attachment 1 to this safety evaluation (SE)].

3.1.2 Applicable ASME Code Requirements The licensee requested relief from the qualification requirements contained in ASME Code,Section XI, 1995 Edition with 1996 Addenda, Appendix VIII, Supplements 2 and 10 as specified in Table VIII-3110-1, for the applicable piping welds.

3.1.3 Licensees Proposed Alternative The licensee stated, pursuant to 10 CFR 50.55a(a)(3)(i), that, in lieu of the requirements of ASME Code,Section XI, 1995 Edition, 1996 Addenda, Appendix VIII, Table VIII-3110-1, the Performance Demonstration Initiative (PDI) Program for implementation of Appendix VIII, Supplement 2 in coordination with Supplement 10 is requested to be used (see RR ISI-28 regarding Supplement 10 implementation) for the remainder of the second 10-year inservice inspection interval for Callaway. The PDI program is a nuclear industry group that was set up to develop rules to implement requirements in Appendix VIII or to develop alternatives to these requirements.

The proposed program has been submitted to the ASME Code for consideration as a new Supplement 14 to Appendix VIII. Supplement 14 is entitled "Qualification Requirements for Coordinated Implementation of Supplement 10, 2, and 3 for Piping Examinations Performed

from the Inside Surface," and is an attachment to RR ISI-27 in the licensee's application.

3.1.4 Licensees Basis for Relief The RPV nozzles to main coolant piping contain ferritic, austenitic, and cast stainless steel components and were assembled using austenitic and dissimilar metal welds. These austenitic and dissimilar metal welds are in close proximity to each other, which means the same ultrasonic essential variables would be employed (e.g., the ultrasonic examination process associated with a dissimilar metal weld would be applied to a ferritic or austenitic weld).

With regard to qualification requirements for the inspection of such welds, separate qualifications to Supplements 2, 3, and 10 are redundant when done in accordance with the industrys PDI Program. For example, during personnel qualification to the PDI Program, a candidate would be exposed to a minimum of ten flawed grading units for each supplement.

Personnel qualification for Supplements 2, 3, and 10 would require a minimum of 30 flawed grading units. Test sets this large are impractical. Additionally, a full procedure qualification (three personnel qualifications per supplement) to the PDI Program requirements for three supplements would require a minimum of 90 flawed grading units. This is particularly burdensome for a procedure that will use the same essential variables or the same criteria for selecting essential variables for the three supplements.

To resolve these issues, the PDI Program recognizes the Supplement 10 qualification as the most stringent and technically challenging ultrasonic application. The same Supplement 10 essential variables are used for the examinations subject to the requirements of Supplements 2 and 3. A coordinated add-on implementation would be sufficiently stringent for qualification to the requirements of Supplements 2 and 3 if the requirements used for qualification to Supplement 10 are satisfied as a prerequisite. The basis for this conclusion is the fact that the majority of the flaws addressed in Supplement 10 are located in the austenitic weld material.

This configuration is known to be challenging for ultrasonic techniques due to the variable dendritic structure of the weld material. Conversely, the flaws addressed in Supplements 2 and 3 initiate in fine-grained base materials.

Additionally, the use of the PDI Program for implementation of Supplement 2 requirements in coordination with Supplement 10 implementation would be more stringent than current ASME Code requirements for detection and length sizing qualifications. For example, the current ASME Code would allow a detection procedure, personnel, and equipment to be qualified to Supplement 10 requirements with 5 flaws, Supplement 2 requirements with 5 flaws, and Supplement 3 requirements with 5 flaws, for a total of only 15 flaws. The proposed alternative of qualifying to Supplement 10 requirements using a minimum of 10 flaws and adding on Supplement 2 requirements with 5 flaws and Supplement 3 requirements with 3 flaws results in a total of 18 flaws which will be multiplied by a factor of 3 (PDI multiplier) for the minimum number of flaws in Supplements 10, 2 and 3 procedure qualification.

Based on the above, the use of a limited number of Supplement 2 or 3 flaws is sufficient to assess the capabilities of procedure and personnel who have already satisfied Supplement 10 requirements. The statistical basis used for screening personnel and procedures is still maintained to the same level with competent personnel being successful and less skilled

personnel being unsuccessful. The proposed alternative is consistent with other coordinated qualifications currently contained in Appendix VIII.

3.1.5 Staff Evaluation The licensee requested relief from selected qualification requirements of ASME Code,Section XI, Appendix VIII, Supplements 2 and 3 for examinations performed from the inside surface. The ASME Code currently requires separate qualifications for austenitic piping (Supplement 2), ferritic piping (Supplement 3), and dissimilar metal piping (Supplement 10).

Qualifications for each supplement would entail a minimum of 10 flaws for each supplement, requiring at least 30 flaws for the three supplements. The minimum number of flaws per supplement established a statistical-based pass/fail objective which is identified in the submittal as Table VIII-S10-1. The process of a single qualification for each supplement would greatly expand the minimum number of ferritic and austenitic flaws required to be identified which would also raise the pass/fail acceptance criteria specified in Table VIII-S10-1.

The ASME Code recognized that flaws in austenitic material are more difficult to detect and size than flaws in ferritic material. The prevailing reasoning concluded that a Supplement 3 qualification following a Supplement 2 qualification had diminished returns on measuring personnel skills and procedure effectiveness. Therefore, in lieu of separate Supplement 2 and Supplement 3 qualifications, the ASME Code applied the diminishing return logic in Supplement 12 which provides for a Supplement 3 add-on to a Supplement 2 qualification. The add-on consists of a minimum of three flaws in ferritic material. All of the flaws in the ferritic material must be detected with no false detections. A statistical evaluation of Supplement 12 acceptance criteria satisfied the pass/fail objective established for Appendix VIII performance demonstration acceptance criteria.

The proposed alternative builds upon the experiences associated with Supplement 12 by starting with the most challenging Supplement 10 qualifications, as implemented by the PDI program (see RR ISI-28 in Section 3.2 of this safety evaluation), and adding a sufficient number of flaws to demonstrate the personnel skills and procedure effectiveness of the less challenging Supplement 2 and Supplement 3 qualifications. A PDI Supplement 10 performance demonstration requires at least one flaw with a maximum of 10 percent of the total number of flaws being in the ferritic material. The rest of the flaws are in the more challenging austenitic material. When expanding the Supplement 10 qualification with an add-on Supplement 2 and Supplement 3 qualification, the proposed alternative would add a minimum of five flaws in austenitic material and three flaws in ferritic material to the performance demonstration. All of the add-on flaws must be detected with no false indications. Therefore, a combined Supplement 2 and Supplement 3, add-on to a Supplement 10 qualification requires a minimum of 8 flaws in the detection performance demonstration test in addition to the minimum of 10 flaws for a Supplement 10 qualification. For the sizing performance demonstration of the Supplement 2 and Supplement 3 results are added to the appropriate Supplement 10 results which must satisfy the acceptance criteria of the Supplement 10. A statistical evaluation performed by Pacific Northwest National Laboratories, an NRC contractor, showed that the proposed alternative acceptance criteria satisfied the pass/fail objective criteria specified in Table VIII-S10-1 of the licensee's application.

The staff has determined that the use of a limited number of flaws to qualify personnel,

procedures and equipment to Supplement 2 or Supplement 3 in coordination with the PDI developed implementation of Supplement 10 (see Section 3.2 of this safety evaluation), will provide equivalent flaw detection performance to that of the ASME Code. As such, the staff

concludes that the licensee's proposed alternative provides an acceptable level of quality and safety.

3.1.6 Conclusion The staff has determined that the proposed alternative to use the industry's PDI program for implementation of Appendix VIII, Supplements 2 and 3 as coordinated with the PDI program for implementation of Appendix VIII, Supplement 10, will provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the NRC authorizes the proposed alternative in RR ISI-27 for the remainder of the second 10-year ISI interval at Callaway.

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

3.2 RR ISI-28 3.2.1 Component for Which Relief is Requested The applicable piping welds in RR ISI-28 are pressure retaining dissimilar metal piping welds subject to examinations using procedures, personnel, and equipment qualified to the 1995 Edition with 1996 Addenda of the ASME Code,Section XI, Appendix VIII, Supplement 10, "Qualification Requirements for Dissimilar Metal Piping Welds" for the remainder of the second 10-year ISI interval. A copy of Supplement 10 was submitted as an attachment to the licensee's application. These applicable welds are listed in the licensee's application and given in Table 2 (Attachment 2 to this SE).

3.2.2 Applicable ASME Code Requirements The following items are from ASME Code,Section XI, Appendix VIII, Supplement 10. They identify the specific requirements that are addressed in RR ISI-28. The following statements are taken from the licensee's application:

Item 1 - Paragraph 1.1(b) states in part - Pipe diameters within a range of 0.9 to 1.5 times a nominal diameter shall be considered equivalent.

Item 2 - Paragraph 1.1(d) states - All flaws in the specimen set shall be cracks.

Item 3 - Paragraph 1.1(d)(1) states - At least 50% of the cracks shall be in austenitic material. At least 50% of the cracks in austenitic material shall be contained wholly in the weld or buttering material. At least 10% of the cracks shall be in ferritic material. The remainder of the cracks may be in either austenitic or ferritic material.

Item 4 - Paragraph 1.2(b) states in part - The number of unflawed grading units shall be at least twice the number of flawed grading units.

Item 5 - Paragraph 1.2(c)(1) and 1.3(c) state in part - At least 1/3 of the flaws, rounded to the next higher whole number, shall have depths between 10% and 30% of the nominal pipe wall thickness. Paragraph 1.4(b) distribution table requires 20% of the flaws to have depths between 10% and 30%.

Item 6 - Paragraph 2.0 the first sentence states - The specimen inside surface and identification shall be concealed from the candidate.

Item 7 - Paragraph 2.2(b) states in part - The regions containing a flaw to be sized shall be identified to the candidate.

Item 8 - Paragraph 2.2(c) states in part - For a separate length sizing test, the regions of each specimen containing a flaw to be sized shall be identified to the candidate.

Item 9 - Paragraph 2.3(a) states - For the depth sizing test, 80% of the flaws shall be sized at a specific location on the surface of the specimen identified to the candidate.

Item 10 - Paragraph 2.3(b) states - For the remaining flaws, the regions of each specimen containing a flaw to be sized shall be identified to the candidate. The candidate shall determine the maximum depth of the flaw in each region.

Item 11 - Table VIII-S2-1 provides the false-call criteria when the number of unflawed grading units is at least twice the number of flawed grading units.

3.2.3 Licensees Proposed Alternative For each of the items listed above, the licensee has proposed, as stated in the application, the following alternatives to the selected paragraphs in the 1995 Edition with 1996 Addenda of the ASME Code,Section XI, Appendix VIII, Supplement 10, requirements for Callaway:

Item 1 - Paragraph 1.1(b) alternative:

The specimen set shall include the minimum and maximum pipe diameters and thicknesses for which the examination procedure is applicable. Pipe diameters within 1/2 in. (13 mm) of the nominal diameter shall be considered equivalent.

Pipe diameters larger than 24 in. (610 mm) shall be considered to be flat. When a range of thicknesses is to be examined, a thickness tolerance of +/-25% is acceptable.

Technical Basis - The change in the minimum pipe diameter tolerance from 0.9 times the diameter to within 1/2 inch of the nominal diameter provides tolerances more in line with industry practice. Though the alternative is less stringent for small pipe diameters they typically have a thinner wall thickness than larger diameter piping. A thinner wall thickness results in shorter sound path distances that reduce the detrimental effects of the curvature. This change maintains consistency between Supplement 10 and the recent revision to

Supplement 2.

Item 2 - Paragraph 1.1(d) alternative:

At least 60% of the flaws shall be cracks, the remainder shall be alternative flaws. Specimens with IGSCC [intergranular stress corrosion cracking] shall be used when available. Alternative flaws shall meet the following requirements:

(1) Alternative flaws, if used, shall provide crack-like reflective characteristics and shall only be used when implantation of cracks would produce spurious reflectors that are uncharacteristic of service-induced flaws actual.

(2) Alternative flaw mechanisms shall have a tip width of no more than 0.002 in

(.05 mm).

Note, to avoid confusion the proposed alternative modifies instances of the term "cracks" or "cracking" to the term "flaws" because of the use of alternative flaw mechanisms.

Technical Basis - ..., implanting a crack requires excavation of the base material on at least one side of the flaw. While this may be satisfactory for ferritic materials, it does not produce a useable axial flaw in austenitic materials because the sound beam, which normally passes only through base material, must now travel through weld material on at least one side, producing an unrealistic flaw response. In addition, it is important to preserve the dendritic structure present in field welds that would otherwise be destroyed by the implantation process. To resolve these issues, the proposed alternative allows the use of up to 40% fabricated flaws as an alternative flaw mechanism under controlled conditions. The fabricated flaws are isostatically compressed which produces ultrasonic reflective characteristics similar to tight cracks.

Item 3 - Paragraph 1.1(d)(1) alternative:

At least 80% of the flaws shall be contained wholly in weld or buttering material.

At least one and no more than 10% of the flaws shall be in ferritic base material.

At least one and no more than 10% of the flaws shall be in austenitic base material.

Technical Basis - Under the current [ASME] Code, as little as 25% of the flaws may be contained in austenitic weld or buttering material. Recent experience has indicated that flaws are most likely to be contained within the weld. The metallurgical structure of austenitic weld material is ultrasonically more challenging than either ferritic or austenitic base material. The proposed alternative is therefore more challenging than the current [ASME] Code.

Item 4 - Paragraph 1.2(b) alternative:

Personnel performance demonstration detection test sets shall be selected from

Table VIII-S10-1. The number of unflawed grading units shall be at least 1-1/2

[one and a half] times the number of flawed grading units.

Technical Basis - Proposed Table VIII-S10-1 provides a statistically based ratio between the number of unflawed grading units and the number of flawed grading units. The proposed alternative reduces the ratio to 1.5, thus reducing the number of test samples to a more reasonable number from the human factors perspective. However, the statistical basis used for screening personnel and procedures is still maintained at the same level with regard to competent personnel being successful and less skilled personnel being unsuccessful. The acceptance criteria for the statistical basis are in new Table Vlll-S10-1.

Item 5 - Paragraph 1.2(c)(1) and 1.3(c) alternative:

The proposed alternative to the flaw distribution requirements of Paragraph 1.2(c)(1) (detection) and 1.3(c) (length) is to use the Paragraph 1.4(b) (depth) distribution table (see below) for all qualifications.

Flaw Depth Minimum

(% Wall Thickness) Number of Flaws 10-30% 20%

31-60% 20%

61-100% 20%

Technical Basis - The proposed alternative uses the depth sizing distribution for both detection and depth sizing because it provides for a better distribution of flaw sizes within the test set. This distribution allows candidates to perform detection, length, and depth sizing demonstrations simultaneously utilizing the same test set. The requirement that at least 75% of the flaws shall be in the range of 10 to 60% of wall thickness provides an overall distribution tolerance yet the distribution uncertainty decreases the possibilities for testmanship that would be inherent to a uniform distribution. It must be noted that it is possible to achieve the same distribution utilizing the present requirements, but it is preferable to make the criteria consistent.

Item 6 - Paragraph 2.0 alternative to the first sentence:

For qualifications from the outside surface, the specimen inside surface and identification shall be concealed from the candidate. When qualifications are performed from the inside surface, the flaw location and specimen identification shall be obscured to maintain a 'blind test.'

Technical Basis - The current [ASME] Code requires that the inside surface be concealed from the candidate. This makes qualifications conducted from the inside of the pipe (e.g., PWR [pressurized water reactor] nozzle to safe end welds) impractical. The proposed alternative differentiates between ID [inner diameter] and OD [outer diameter] scanning surfaces, requires that they be

conducted separately, and requires that flaws be concealed from the candidate.

This is consistent with the recent revision to Supplement 2.

Items 7 and 8 - Paragraph 2.2(b) and 2.2(c) alternative:

. . . containing a flaw to be sized may be identified to the candidate.

Technical Basis - The current [ASME] Code requires that the regions of each specimen containing a flaw to be length sized shall be identified to the candidate.

The candidate shall determine the length of the flaw in each region. (Note that length and depth sizing use the term "regions," while detection uses the term "grading units." The two terms define different concepts and are not intended to be equal or interchangeable.) To ensure security of the samples, the proposed alternative modifies the first "shall" to a "may" to allow the test administrator the option of not identifying specifically where a flaw is located. This is consistent with the recent revision to Supplement 2."

Items 9 and 10 - Paragraph 2.3(a) and 2.3(b) alternative:

. . . regions of each specimen containing a flaw to be sized may be identified to the candidate.

Technical Basis - The current [ASME] Code requires that a large number of flaws be sized at a specific location. The proposed alternative changes the "shall" to a "may" which modifies this from a specific area to a more generalized region to ensure security of samples. This is consistent with the recent revision to Supplement 2. It also incorporates terminology from length sizing for additional clarity.

Item 11 - Table VIII-S2-1 alternative:

The proposed alternative modifies the acceptance criteria of Table VIII-S2-1 as

[shown in the attachment for RR ISI-28 to the licensee's application]

Technical Basis - The proposed alternative is identified as new Table VIII-S10-1

... It was modified to reflect the reduced number of unflawed grading units and allowable false calls. As a part of ongoing [ASME] Code activities, Pacific Northwest National Laboratory (PNNL) has reviewed the statistical significance of these revisions and offered the revised Table VIII-S10-1.

The licensee stated that the proposed alternatives will be implemented through the PDI Program.

3.2.4 Staff Evaluation The licensee proposed to use the PDI program that is similar to the ASME Code requirements.

The differences between the ASME Code and the PDI program are discussed item by item below.

Item 1 - Paragraph 1.1(b)

The ASME Code requirement of "0.9 to 1.5 times the nominal diameter are equivalent" was established for a single nominal diameter. When applying the ASME Code-required tolerance to a range of diameters, the tolerance rapidly expands on the high side. Under the current ASME Code requirements, a 5-inch OD pipe would be equivalent to a range of 4.5-inch to 7.5-inch diameter pipe. Under the proposed PDI guidelines, the equivalent range would be reduced to 4.5-inch to 5.5-inch diameter. With current ASME Code requirements, a 16-inch nominal diameter pipe would be equivalent to a range of 14.4-inch to 24-inch diameter pipe.

The proposed alternative would significantly reduce the equivalent range of 15.5-inch to 16.5-inch diameter pipe. The difference between ASME Code and the proposed alternative for diameters less than 5 inches is not significant because of shorter metal path and beam spread associated with smaller diameter piping. The proposed alternative is considered more conservative overall than current ASME Code requirements. Based on this, the staff finds that the proposed alternative will provide an acceptable level of quality and safety and, therefore, is acceptable.

Item 2 - Paragraph 1.1(d)

The ASME Code requires all flaws to be cracks. Manufacturing test specimens containing cracks free of spurious reflections and telltale indicators is extremely difficult in austenitic material. To overcome these difficulties, PDI developed a process for fabricating flaws that produce ultrasonic testing (UT) acoustic responses similar to the responses associated with real cracks. The PDI program presented its process for discussion at public meetings held June 12 through 14, 2001, and January 31 through February 2, 2002, at the Electric Power Research Institute (EPRI) Nondestructive Examination (NDE) Center, Charlotte, NC. The staff attended these meetings and determined that the process parameters used for manufacturing fabricated flaws resulted in acceptable acoustic responses. Based on this, the staff finds that the proposed alternative will provide an acceptable level of quality and safety and, therefore, is acceptable.

Item 3 - Paragraph 1.1(d)(1)

The ASME Code requires that at least 50 percent of the flaws be contained in austenitic material, and 50 percent of the flaws in the austenitic material shall be contained fully in weld or buttering material. This means that at least 25 percent of the total flaws must be located in the weld or buttering material. Field experience shows that flaws identified during ISI of dissimilar metal welds are more likely to be located in the weld or buttering material. The grain structure of austenitic weld and buttering material represents a much more stringent ultrasonic scenario than that of a ferritic material or austenitic base material. Flaws made in austenitic base material are difficult to create free of spurious reflectors and telltale indicators. The proposed alternative of 80 percent of the flaws in the weld metal or buttering material provides a challenging testing scenario reflective of field experience and minimizes testmanship associated with telltale reflectors common to placing flaws in austenitic base material.

Therefore, the staff considers the proposed alternative to be more conservative than current ASME Code requirements. Based on this, the staff finds that the proposed alternative will provide an acceptable level of quality and safety and, therefore, is acceptable.

Item 4 - Paragraph 1.2(b) and Item 11 - Table VIII-S2-1 The ASME Code requires that detection sets meet the requirements of Table VIII-S2-1, which specifies the minimum number of flaws in a test set to be 5 with 100 percent detection. The current ASME Code also requires the number of unflawed grading units to be two times the number of flawed grading units. The proposed alternative would follow the detection criteria of the table beginning with a minimum number of flaws in a test set being 10, and reducing the number of false calls to 11/2 times the number of flawed grading units. The changes to Table VIII-S2-1 are shown in Table VIII-S10-1. Therefore, the staff finds that the proposed alternative satisfies the pass/fail objective established for Appendix VIII performance demonstration acceptance criteria. Based on this, the staff finds that the proposed alternative will provide an acceptable level of quality and safety and, therefore, is acceptable.

Item 5 - Paragraph 1.2(c)(1) and 1.3(c)

For detection and length sizing, the ASME Code requires at least one third of the flaws be located between 10 and 30 percent through-wall thickness and one third located greater than 30 percent through-wall thickness. The remaining flaws would be located randomly throughout the wall thickness. The proposed alternative sets the distribution criteria for detection and length sizing to be the same as the depth sizing distribution, which stipulates that at least 20 percent of the flaws be located in each of the increments of 10-30 percent, 31-60 percent and 61-100 percent. The remaining 40 percent would be located randomly throughout the wall thickness. With the exception of the 10-30 percent increment, the proposed alternative is a subset of the current ASME Code requirements. The 10-30 percent increment would be in the subset if it contained at least 30 percent of the flaws. The change simplifies assembling test sets for detection and sizing qualifications and is more indicative of conditions in the field.

Based on this, the staff finds that the proposed alternative will provide an acceptable level of quality and safety and, therefore, is acceptable.

Item 6 - Paragraph 2.0 The ASME Code requires the specimen inside surface be concealed from the candidate. This requirement is applicable for test specimens used for qualification performed from the outside surface. With the expansion of Supplement 10 to include qualifications performed from the inside surface, the inside surface must be accessible while maintaining the specimen integrity.

The proposed alternative requires that flaws and specimen identifications be obscured from candidates, thus maintaining blind test conditions. Therefore, the staff considers this to be consistent with the intent of ASME Code requirements. Based on this, the staff finds that the proposed alternative will provide an acceptable level of quality and safety and, therefore, is acceptable.

Items 7 and 8 - Paragraph 2.2(b) and 2.2(c)

The ASME Code requires that the location of flaws added to the test set for length sizing shall be identified to the candidate. The proposed alternative is to make identifying the location of additional flaws an option. This option provides an additional element of difficulty to the testing process because the candidate would be expected to demonstrate the skill of detecting and

sizing flaws over an area larger than a specific location. Therefore, the staff considers the proposed alternative to be more conservative than current ASME Code requirements. Based on this, the staff finds that the proposed alternative will provide an acceptable level of quality and safety and, therefore, is acceptable.

Item 9 - Paragraph 2.3(a)

In paragraph 2.3(a), the ASME Code requires that 80 percent of the flaws be sized in a specific location that is identified to the candidate. The proposed alternative permits detection and depth sizing to be conducted separately or concurrently. In order to maintain a blind test, the location of flaws cannot be shared with the candidate. For depth sizing that is conducted separately, allowing the test administrator the option of not identifying flaw locations makes the testing process more challenging. Therefore, the staff considers the proposed alternative to be more conservative than current ASME Code requirements. Based on this, the staff finds that the proposed alternative will provide an acceptable level of quality and safety and, therefore, is acceptable.

Item 10 - Paragraph 2.3(b)

In paragraph 2.3(b), the ASME Code also requires that the location of flaws added to the test set for depth sizing shall be identified to the candidate. The proposed alternative is to make identifying the location of additional flaws an option. This option provides an additional element of difficulty to the testing process because the candidate would be expected to demonstrate the skill of finding and sizing flaws in an area larger than a specific location. The staff considers the proposed alternative to be more conservative than current ASME Code requirements. Based on this, the staff finds that the proposed alternative will provide an acceptable level of quality and safety and, therefore, is acceptable.

Item 11 - Table VIII-S2-1 See the discussion for Item 4 and Item 11 on page 11 of this SE.

3.2.5 Conclusion As discussed above, the staff has determined that the proposed alternative in RR ISI-28 to Supplement 10, as administered by the PDI Program, will provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the staff authorizes the proposed alternative in RR ISI-28 for the remainder of the second 10-year ISI interval at Callaway. 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.

3.3 RR ISI-29 3.3.1 Component for Which Relief is Requested The applicable piping welds in RR ISI-29 are ASME Code,Section XI, Class1, Examination Category B-A, Item no. B1.10 longitudinal and circumferential shell welds and B1.20 head

welds subject to Appendix VIII, Supplement 4 examinations. These applicable welds are listed in the licensee's application and given in Table 3 (Attachment 3 to this SE).

3.3.2 Applicable ASME Code Requirements The applicable code requirements are in the ASME Code,Section XI, 1995 Edition with 1996 Addenda, Appendix VIII, Supplement 4, Subparagraph 3.2(c).

3.3.3 Licensees Proposed Alternative At Callaway, the licensee proposes to use the depth size requirement of 0.15-inch root mean square (RMS) consistent with 10 CFR 50.55a(b)(2)(xv)(C)(1) in lieu of the requirements contained in ASME Code,Section XI, Appendix VIII, Supplement 4, Subparagraph 3.2(c).

3.3.4 Licensees Basis for Relief As stated in RR ISI-29 attached to the licensee's application:

Supplement 4, Subparagraph 3.2(c), imposes three statistical parameters for depth sizing. The first parameter, 3.2(c)(1), pertains to the slope of a linear regression line. The linear regression line is the difference between measured versus true value plotted along a through-wall thickness. For Supplement 4 performance demonstrations, a linear regression line of the data is not applicable because the performance demonstrations are performed on test specimens with flaws located in the inner 15 percent through-wall. The difference between the measured versus true value produce a tight grouping of results, which resemble a shotgun pattern. The slope of a regression line from such data is extremely sensitive to small variations, thus making the parameter of Subparagraph 3.2(c)(1) a poor and inappropriate acceptance criterion. The second parameter, 3.2(c)(2), pertains to the mean deviation of flaw depth. The value used in the ASME Code is too lax with respect to evaluation flaw depths within the inner 15 percent of wall thickness. Therefore, PDI proposes to use the more appropriate criterion of 0.15-inch RMS of 10 CFR 50.55a(b)(2)(xv)(C)(1), which modifies Subparagraph 3.2(a), as the acceptance criterion. The third parameter, 3.2(c)(3), pertains to a correlation coefficient. The value of the correlation coefficient in Subparagraph 3.2(c)(3) is inappropriate for this application since it is based on the linear regression from Subparagraph 3.2(c)(1).

3.3.5 Staff Evaluation Supplement 4, Subparagraph 3.2(c) of Appendix VIII, requires that the ultrasonic performance demonstration results be plotted on a two-dimensional plot, with the measured depth plotted along the ordinate axis and the true depth plotted along the abscissa axis. For qualification, the plot must satisfy the following statistical parameters: (1) slope of the linear regression line is not less than 0.7, (2) the mean deviation of flaw depth is less than 0.25 inch, and (3) the correlation coefficient is not less than 0.7.

The licensee proposes to eliminate the use of Supplement 4, Subparagraph 3.2(c), which imposes three statistical parameters for depth sizing. For the reasons stated by the licensee in Subsection 3.3.4, the staff agrees that the use of Subparagraph 3.2(c) is not appropriate when implementing Appendix VIII, Supplement 4 in accordance with 10 CFR 50.55a(b)(2)(xv). The

staff recognized this issue, and as a result has addressed its resolution in a proposed change to 10 CFR 50.55a (69 FR 892). The licensee's proposed alternative is consistent with the proposed rule change.

Based on the above, the staff has determined that the use of Subparagraph 3.2(c) requirements is inappropriate as a screening parameter for determining the acceptability of Supplement 4 performance demonstration results. Therefore, the proposed alternative to use the RMS value of the proposed rule 10 CFR 50.55a(b)(2)(xv)(C(1), which modifies the criterion of Appendix VIII, Supplement 4, Subparagraph 3.2(a), and applies the same criterion to Subparagraph 3.2(c), specifically 0.15 inch RMS, will provide an acceptable level of quality and safety.

3.3.6 Conclusion Based on the above, the staff finds that the use of Subparagraph 3.2(c) requirements in this context is inappropriate and the proposed alternative in RR ISI-29 to use the RMS value of 10 CFR 50.55a(b)(2)(xv)(C)(1), which modifies the criterion of Appendix VIII, Supplement 4, Subparagraph 3.2(a), in lieu of Subparagraph 3.2(c) will provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the staff authorizes the proposed alternative in RR ISI-29 for the second 10-year ISI interval at Callaway. 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.

3.4 RR ISI-30 3.4.1 Component for Which Relief is Requested The applicable piping weld for RR ISI-30 is one of the ASME Code Class 1, Category B-A pressure retaining welds in the RPV, Item No. B1.30 upper shell to flange weld. It is weld No.

2-RV-101-121.

3.4.2 Applicable ASME Code Requirements The applicable code requirements are in the 1989 Edition of ASME Code,Section XI, Subsection IWA-2232, that requires UT examinations of RPV-to-flange weld to be in accordance with ASME Code,Section V, Article 4. In addition, the recommendations in Regulatory Guide (RG) 1.150, Revision 1, "Ultrasonic Testing of Reactor Vessel Welds During Preservice and Inservice Examinations," which the licensee has committed to follow, augments the ASME Code requirements.

3.4.3 Licensees Proposed Alternative The licensee proposed using qualified personnel and procedures for remote mechanized examination of the reactor vessel flange-to-shell weld in accordance with the 1995 Edition with 1996 Addenda of the ASME Code,Section XI, Appendix VIII, Supplements 4 and 6, in lieu of Section V, Article 4 requirements.

3.4.4 Licensees Basis for Relief Although Appendix VIII is not required for this weld, using an examination procedure and personnel qualified in accordance with Appendix VIII will provide an increased margin of safety and surpass the quality of the generic examination techniques specified by the referencing ASME Code edition. Compliance with these requirements will assure the requisite level of quality and safety is maintained.

The September 22, 1999, revision of 10 CFR 50.55a required implementation of ASME Code,Section XI, Appendix VIII, Supplement 4 (clad-base metal interface) and Supplement 6 (vessel welds other than clad-base metal interface). The reactor vessel shell welds are subject to examination in accordance with these supplements, however, the flange-to-shell weld is the only reactor vessel shell weld not included in Appendix VIII.

For the Callaway reactor vessel examination planned for the upcoming refueling outage in April 2004, the licensee will be employing procedures, equipment, and personnel qualified by performance demonstration in accordance with ASME Code,Section XI, 1995 Edition, 1996 Addenda, as amended by 10 CFR 50.55a. The ASME Code requirements as amended by the final rule will be complied with by using Westinghouse Procedure PDI-ISI-254.

Appendix VIII was developed to ensure the effectiveness of UT examinations within the nuclear industry by means of a rigorous, item-specific performance demonstration. The performance demonstration was conducted on a RPV mockup containing flaws of various sizes and locations. The demonstration established the capability of equipment, procedures, and personnel to find flaws that could be detrimental to the integrity of the RPV.

A comparison between the ASME Code,Section V, Article 4 based UT methods and the procedures developed to satisfy PDI/Appendix VIII can be best described as a comparison between a compliance-based procedure (ASME Code,Section V, Article 4) and a results-based procedure (PDI Appendix VIII). ASME Code,Section V procedures use an amplitude-based technique and a known reflector. The proposed alternate UT method was established independently from the acceptance standards for flaw size found in ASME Code,Section XI.

Because the PDI qualified sizing method is considered more accurate than the method used in ASME Code,Section V, Article 4, the licensee stated that the proposed alternate UT examination technique will provide an acceptable level of quality and examination repeatability as compared to the Article 4 requirements.

The PDI Program's performance demonstration qualification sheet (PDQS) No. 407 attests that Westinghouse Procedure PDI-ISI-254 is in compliance with the detection and sizing tolerance requirements of Appendix VIII. The PDI qualification method is based on a group of samples, which validate the acceptance flaw sizes in ASME Code,Section XI. The sensitivity to detect these flaws is considered to be equal or greater than the sensitivity obtained through ASME Code,Section V, Article 4 because Procedure PDI-ISI-254 relies on a smaller scan index and a higher scan sensitivity for the detection of the UT signals.

The examination and sizing procedure uses echo-dynamic motion and tip diffraction

characteristics of the flaw instead of the amplitude characteristics required by ASME Code,Section V, Article 4. The search units interrogate the same examination volume as depicted by ASME Code,Section XI, Figure IWB-2500-4, "Shell-to-Flange Weld Joint."

The use of procedures for satisfying the requirements of ASME Code Section V, Article 4 for the UT examination of the RPV-to-flange weld from the vessel shell has not received the same qualifications as a PDI qualified procedure.

The PDI qualification specimens are curved vessel shell plate sections and do not have a taper transition geometry. However, the procedure is used to examine reactor vessel shell welds which have taper transitions at weld joints of dissimilar thickness. The PDI qualification for Supplements 4 and 6 allows for examination of material thickness up to 12.3 inches or a metal path distance of 17.5 inches in the case of the 45 degree transducer. This qualified test range bounds a significant percentage of the flange-to-shell weld examination volume even in the thicker portion of the weld centerline.

Callaway's RPV flange-to-shell weld was examined during the pre-service by remote automated inspection in accordance with Section XI. The pre-service examination was performed from the vessel ID surface, using Section XI techniques at 0 degree longitudinal and 45 and 60 degree shear beam angles. Examination from the flange surface was performed using 0, 8, and 19 degree longitudinal. For inservice examinations, during the first interval the weld examination from the flange surface was performed in accordance with Section XI using 0, 6, 12 and 16 degree longitudinal. The weld ID surface examination was performed using 45 and 60 degree shear wave, and 45/70 degree longitudinal beam angles by remote automated inspection in accordance with Section XI and RG 1.150, Revision 1. The licensee stated that no matters of concern were identified during the aforementioned examinations.

The use of Appendix VIII Supplements 4 and 6 for the completion of the RPV vessel-to-flange weld from the shell side (which the PDI group has qualified) is expected to reduce personnel radiation exposure.

Additionally, this relief would allow a smooth transition to the welds adjacent to the RPV circumferential and longitudinal welds (welds B 1.11 and B 1.12) which do require an examination in accordance with Appendix VIII, Supplements 4 and 6. This would eliminate the need to switch to the different calibrations, procedures, and techniques required by ASME Code,Section V, Article 4 and RG 1.150, Revision 1. This would result in a reduction in transition time to the different calibration, procedure, and technique required which translates to reduced personnel radiation exposure and is more cost effective.

3.4.5 Staff Evaluation The 1989 Edition of Section XI IWA-2232 states, "Ultrasonic examination shall be conducted in accordance with Appendix I." I-2100 of Appendix I states, "Ultrasonic examination of vessel welds greater than 2 in. thickness shall be conducted in accordance with Article 4 of Section V, as supplemented by this Appendix [Appendix I of Section XI]." Supplements identified in Table I-2000-1 shall be applied.Section V, Article 4 as supplemented by Appendix I provides a prescriptive-based process for qualifying UT procedures. In lieu of ASME Code,Section XI requirements, the licensee proposed using procedures and personnel qualified in accordance with the performance-based criteria as implemented by the PDI program for the examination of reactor pressure vessels, ASME Code,Section XI, Appendix VIII, Supplements 4 and 6. The licensee contracted the services of Westinghouse to perform the examinations using

Westinghouse Procedure PDI-ISI-254.

When qualified prescriptive-based UT procedures are applied in a controlled setting containing real flaws in mockups of reactor vessels and the results are statistically analyzed according to the screening criteria in Appendix VIII of Section XI of the ASME Code, the procedures are equal to or less effective than UT Appendix VIII, Supplement 4 and 6 qualified procedures.

A tabulation of the differences between the performance-based Westinghouse procedure PDI-ISI-254, Revision 5 and Section V, Article 4 requirements is shown in Table 1 submitted in the licensees letter dated October 23, 2003. Whereas the performance-based UT uses fewer transducers than Section V, the performance-based UT is performed with higher sensitivity which increases the chances of detecting a flaw when compared to prescriptive-based Section V, Article 4 requirements. Also, flaw sizing is more accurately determined with the echo-dynamic motion and tip diffraction criteria used by performance-based UT as opposed to the less accurate amplitude criteria for prescriptive-based Section V, Article 4 requirements.

Procedures, equipment, and personnel qualified through the PDI program have shown high probability of detection levels. Based on this, the staff concludes that this has resulted in an increased reliability of inspections for weld configurations within the scope of the PDI program.

3.4.6 Conclusion Based on the increased reliability of inspections within the scope of the PDI program, as discussed above, the staff concludes that the licensees proposed alternative in RR ISI-30 to use UT procedures and personnel qualified to the 1995 Edition with 1996 Addenda of Section XI of the ASME Code, Appendix VIII, Supplements 4 and 6 as modified by 10 CFR 50.55a(b)(2)(xv) for the RPV shell-to-flange weld, is acceptable. Based on this conclusion, the staff has determined that the proposed alternative examination with PDI qualified procedures and personnel of the shell-to-flange weld would provide an equivalent or better examination than the current ASME Code requirements or the RG 1.150, Revision 1, recommendations.

Therefore, the staff concludes that the alternatives in RR ISI-30 will provide an acceptable level of quality and safety and, therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the proposed alternative in ISI-30 is authorized for the subject flange-to-vessel weld at Callaway for the second 10-year ISI interval. All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in this relief request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.

3.5 RR ISI-31 3.5.1 Component for Which Relief is Requested The applicable piping welds in RR ISI-131 are Class 1 RPV pressure-retaining nozzle-to-vessel welds. The applicable welds are listed in the licensee's application and in Table 4 (Attachment 4 to this SE).

3.5.2 Applicable ASME Code Requirements The applicable code requirements are in the ASME Code,Section XI, 1989 Edition, Examination Category B-D Full Penetration Welds of Nozzles in Vessels, Code Item B3.90,

Figure IWB-2500-7(a) and (b).

ASME Code,Section V, 1989 Edition, Article 4, Paragraphs T-441.3.2.5, Angle Beam Scanning; T-3.2.6, "Scanning for Reflectors Oriented Parallel to the Weld;" and T-441.3.2.7, "Scanning for Reflectors Oriented Transverse to the Weld."

3.5.3 Licensees Proposed Alternative The licensee proposed the following alternative to the examination requirements in the ASME Code:

1. Perform examinations in accordance with the ASME Code Case N-613-1

2. Perform examinations in accordance with ASME Code,Section XI, Division 1, 1995 Edition with the 1996 Addenda, Appendix VIII, Supplement 7.

3.5.4 Licensees Basis for Relief Inservice examination of selected welds is currently performed in accordance with the requirements of 10 CFR 50.55a, the Callaway Technical Specifications, and the 1989 Edition of the ASME Code,Section XI. This ASME Code edition invokes the examination requirements of Appendix I, Article I-2000 which refers to ASME Code,Section V, Article 4. The licensee stated that these requirements are based on an examination methodology that is outdated.

The licensee explained that the required examination volume for the RPV pressure retaining nozzle-to-vessel welds extends far beyond the weld into the base metal, and is unnecessarily large. This extends the examination time significantly and results in no net increase in safety.

The licensee stated that the relief in RR ISI-31 is requested to use the alternative requirements of ASME Code Case N-613-1, Figures 1 and 2 for examination volume, and the requirements of ASME Code,Section XI, Division 1, 1995 Edition with the 1996 Addenda, Appendix VIII, Supplement 7 in lieu of the requirements of ASME Code,Section XI, Figures IWB-2500-7(a) and IWB-2500-7(b) and ASME Code,Section V, Article 4, for the performance of the required volumetric examinations as specified in Table IWB-2500-1, Category B-D, of the 1989 Edition of ASME Code,Section XI. These examinations will be performed during the second inspection interval.

The required examinations will be performed using procedures qualified in accordance with ASME Code,Section XI, Division 1, 1995 Edition with the 1996 Addenda, Appendix VIII, Supplement 7. This will provide added assurance that the reactor vessel welds have remained free of service-related flaws, thus enhancing quality and ensuring plant safety and reliability.

The licensee stated that Code Case N-613-1 reduces the examination volume next to the widest part of the weld from half of the vessel wall thickness to one-half (1/2) inch. This reduction removes from examination the base metal that was extensively examined during construction and preservice inspection and is not in the high residual stress region associated with the weld. The licensee explained that (1) cracks, should they initiate, occur in the high-stress areas of the weld, and (2) these high-stress areas are contained in the volume that is defined by Code Case N-613-1 and are thus subject to examination.

3.5.5 Staff Evaluation The acceptability of the reduced UT examination volume is based on previous volumetric examinations of the welds and the required volume of base metal, which extends out from the weld for a distance equivalent to one-half the through-wall shell thickness. The previous volumetric examinations showed the ASME Code volume to be free of unacceptable flaws. In addition, the base metal region was extensively examined during construction of the vessel.

The initiation of flaws during plant service in the volume excluded in the proposed reduced examination volume is unlikely because of the low stresses in the base metal away from the weld. The stresses caused by welding are concentrated at, or near, the weld. The staff agrees with the licensee that (1) if cracks are initiated they would occur in the highly stressed area of the weld, and (2) these areas are within the volume included in the proposed reduced examination volume in Code Case N-613-1.

Based on the above, the staff finds that the areas to be excluded from UT examination by the proposed alternative, have previously been found to be free of unacceptable flaws during previous inspections. The staff further finds that the initiation of flaws in the unexamined regions is highly unlikely due to the lower stresses in these regions. Therefore, the staff finds that the proposed alternative to reduce the UT examination volume to one-half inch from the nozzle-to-vessel weld on each side of the weld crown will provide an acceptable level of quality and safety.

In regard to performing the subject examinations in accordance with ASME Code,Section XI, Division 1, 1995 Edition with the 1996 Addenda, Appendix VIII, Supplement 7, the staff notes that the qualification, scanning and coverage requirements of:

• 10 CFR 50.55a(b)(2)(xv)(G) to the extent possible but not less than 10 CFR 50.55a(b)(2)(xv)(K)(2) for examinations performed from inside the vessel, or

• 10 CFR 50.55a(b)(2)(xv)(G) and 10 CFR 50.55a(b)(2)(xv)(K)(3) for examinations performed from the outside surface of the vessel must still be met. Therefore, performing examinations qualified with Appendix VIII, Supplement 7 alone does ensure adequate performance for the scanning coverage and sizing capability of the examination volume defined in CC N-613-1 for the subject nozzle to vessel welds.

3.5.6 Conclusion Based on its review, the staff has determined that the proposed alternative to use the examination volumes defined in Code Case N-613-1 will provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the staff authorizes the proposed alternative examination volume in RR ISI-31 for the second 10-year ISI interval at Callaway.

The staff's authorization is limited to the eight primary nozzle-to-vessel welds. All other requirements of the ASME Code,Section XI, for which relief has not been specifically requested remain applicable, including third party review by the Authorized Nuclear Inservice Inspector. In addition, the requirements of 10 CFR 50.55a(b)(2)(xv)(G) and 10 CFR

50.55a(b)(2)(xv)(K)(2) for examinations performed from inside the vessel or the requirements of 10 CFR 50.55a(b)(2)(xv)(G) and 10 CFR 50.55a(b)(2)(xv)(K)(3) for examinations performed from the outside surface must still be met.

4.0 CONCLUSION

The staff has evaluated RRs ISI-27 through ISI-31 against the requirements of Section XI of the 1989 Edition of the ASME Code, which is the applicable ASME Code for Callaway. Based on the above safety evaluation, the staff concludes that the alternatives to the requirements in Section XI of the ASME Code in the five RRs provide an acceptable level of quality and safety.

Based on this, pursuant to 10 CFR 50.55a(a)(3)(i), the Commission authorizes the proposed alternatives in RRs ISI-27 through ISI-31 for the remainder of the second 10-year ISI interval at Callaway. All other requirements of the ASME Code,Section XI, for which relief has not been specifically requested remain applicable, including third party review by the Authorized Nuclear Inservice Inspector. In addition, the requirements of 10 CFR 50.55a(b)(2)(xv)(G) and 10 CFR 50.55a(b)(2)(xv)(K)(2) for examinations performed from inside the vessel or the requirements of 10 CFR 50.55a(b)(2)(xv)(G) and 10 CFR 50.55a(b)(2)(xv)(K)(3) for examinations performed from the outside surface must still be met.

Attachments: 1. Table 1 - ASME Code Category B-F Safe-End Welds and Category B-J Safe-End Welds

2. Table 2 - Category B-F Safe-End Welds

3. Table 3 - Shell and Head Welds

4. Table 4 - Category B-D Nozzle Welds Principal Contributor: Andrea Keim Date: April 7, 2004

TABLE 1 ASME Code Category B-F Safe-End Welds Code Description Weld Number Item B5.10 Safe-end to Loop A RPV Inlet Nozzle 2-RV-302-121-A (Note 1)

B5.10 Safe-end to Loop A RPV Outlet Nozzle 2-RV-301-121-A (Note 1)

B5.10 Safe-end to Loop B RPV Inlet Nozzle 2-RV-302-121-B B5.10 Safe-end to Loop B RPV Outlet Nozzle 2-RV-301-121-B B5.10 Safe-end to Loop C RPV Inlet Nozzle 2-RV-302-121-C B5.10 Safe-end to Loop C RPV Outlet Nozzle 2-RV-301-121-C B5.10 Safe-end to Loop D RPV Inlet Nozzle 2-RV-302-121-D (Note 1)

B5.10 Safe-end to Loop D RPV Outlet Nozzle 2-RV-301-121-D Category B-J Safe-End Welds Code Description Weld Number Item B9.11 Elbow to Loop A RPV Inlet Safe-End Weld 2-BB-01-F102 (Note 1)

B9.11 Pipe to Loop A RPV Outlet Safe-End Weld 2-BB-01-F103 (Note 1)

B9.11 Elbow to Loop B RPV Inlet Safe-End Weld 2-BB-01-F202 B9.11 Pipe to Loop B RPV Outlet Safe-End Weld 2-BB-01-F203 B9.11 Elbow to Loop C RPV Inlet Safe-End Weld 2-BB-01-F302 B9.11 Pipe to Loop C RPV Outlet Safe-End Weld 2-BB-01-F303 B9.11 Elbow to Loop D RPV Inlet Safe-End Weld 2-BB-01-F402 B9.11 Pipe to Loop D RPV Outlet Safe-End Weld 2-BB-01-F403 Note 1: Welds noted are required to be examined in accordance with the ISI Program Plan at Callaway. Due to the V.C. Summer hot leg nozzle cracking, it was decided by Callaway that all inlet and outlet nozzle-to-safe end welds and all inlet and outlet nozzle safe end-to-pipe welds are to be examined during Refuel 13 (Spring 2004).

Attachment 1

TABLE 2 Category B-F Safe-End Welds Code Description Weld Number Item B5.10 Safe-end to Loop A RPV Inlet Nozzle 2-RV-302-121-A (Note 1)

B5.10 Safe-end to Loop A RPV Outlet Nozzle 2-RV-301-121-A (Note 1)

B5.10 Safe-end to Loop B RPV Inlet Nozzle 2-RV-302-121-B B5.10 Safe-end to Loop B RPV Outlet Nozzle 2-RV-301-121-B B5.10 Safe-end to Loop C RPV Inlet Nozzle 2-RV-302-121-C B5.10 Safe-end to Loop C RPV Outlet Nozzle 2-RV-301-121-C B5.10 Safe-end to Loop D RPV Inlet Nozzle 2-RV-302-121-D (Note 1)

B5.10 Safe-end to Loop D RPV Outlet Nozzle 2-RV-301-121-D Note 1: Welds noted are required to be examined in accordance with the ISI Program Plan at Callaway. Due to the V.C. Summer hot leg nozzle cracking, the licensee decided that all inlet and outlet nozzle-to-safe end welds and all inlet and outlet nozzle safe end-to-pipe welds are to be examined during Refuel 13 (Spring 2004).

Attachment 2

TABLE 3 SHELL AND HEAD WELDS Code Description Weld Number Item B1.11 Circumferential Vessel Shell Weld 2-RV-103-121 B1.11 Circumferential Vessel Shell Weld 2-RV-101-171 B1.12 Intermediate Shell Longitudinal Weld 2-RV-101-124A B1.12 Intermediate Shell Longitudinal Weld 2-RV-101-124B B1.12 Intermediate Shell Longitudinal Weld 2-RV-101-124C B1.12 Lower Shell Longitudinal Weld 2-RV-101-142A B1.12 Lower Shell Longitudinal Weld 2-RV-101-142B B1.12 Lower Shell Longitudinal Weld 2-RV-101-142C B1.12 Upper Shell Longitudinal Weld 2-RV-101-122A B1.12 Upper Shell Longitudinal Weld 2-RV-101-122B B1.12 Upper Shell Longitudinal Weld 2-RV-101-122C B1.21 Lower Torus to Shell Weld 2-RV-101-141 B1.21 Lower Torus to Dollar Plate Weld 2-RV-102-151 B1.22 0E Meridional Weld in Lower Torus 2-RV-101-154A B1.22 90E Meridional Weld in Lower Torus 2-RV-101-154B B1.22 180E Meridional Weld in Lower Torus 2-RV-101-154C B1.22 270E Meridional Weld in Lower Torus 2-RV-101-154D B1.30 Flange to Vessel Weld 2-RV-101-121 Attachment 3

TABLE 4 Category B-D Nozzle Welds Code Description Weld Number Item B3.90 Loop A Outlet Nozzle to Vessel Weld 2-RV-107-121-A B3.90 Loop A Inlet Nozzle to Vessel Weld 2-RV-105-121-A B3.90 Loop B Outlet Nozzle to Vessel Weld 2-RV-107-121-B B3.90 Loop B Inlet Nozzle to Vessel Weld 2-RV-105-121-B B3.90 Loop C Outlet Nozzle to Vessel Weld 2-RV-107-121-C B3.90 Loop C Inlet Nozzle to Vessel Weld 2-RV-105-121-C B3.90 Loop D Outlet Nozzle to Vessel Weld 2-RV-107-121-D B3.90 Loop D Inlet Nozzle to Vessel Weld 2-RV-105-121-D Attachment 4

Callaway Plant, Unit 1 cc:

Professional Nuclear Consulting, Inc. Mr. Rick A. Muench 19041 Raines Drive President and Chief Executive Officer Derwood, MD 20855 Wolf Creek Nuclear Operating Corporation P.O. Box 411 John ONeill, Esq. Burlington, KA 66839 Shaw, Pittman, Potts & Trowbridge 2300 N. Street, N.W. Mr. Dan I. Bolef, President Washington, D.C. 20037 Kay Drey, Representative Board of Directors Coalition for the Mr. Mark A. Reidmeyer, Regional Environment Regulatory Affairs Supervisor 6267 Delmar Boulevard Regulatory Affairs University City, MO 63130 AmerenUE P.O. Box 620 Mr. Lee Fritz, Presiding Commissioner Fulton, MO 65251 Callaway County Court House 10 East Fifth Street U.S. Nuclear Regulatory Commission Fulton, MO 65151 Resident Inspector Office 8201 NRC Road Mr. David E. Shafer Steedman, MO 65077-1302 Superintendent, Licensing Regulatory Affairs Mr. Chris Younie AmerenUE Manager, Quality Assurance P.O. Box 66149, MC 470 AmerenUE St. Louis, MO 63166-6149 P.O. Box 620 Fulton, MO 65251 Mr. Keith D. Young Manager, Regulatory Affairs Manager - Electric Department AmerenUE Missouri Public Service Commission P.O. Box 620 301 W. High Fulton, MO 65251 P.O. Box 360 Jefferson City, MO 65102 Mr. Scott Clardy, Director Section for Environmental Public Health Regional Administrator, Region IV P.O. Box 570 U.S. Nuclear Regulatory Commission Jefferson City, MO 65102-0570 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Certrec Corporation 4200 South Hulen, Suite 630 Mr. Ronald A. Kucera Fort Worth, TX 76109 Deputy Director for Public Policy Department of Natural Resources P.O. Box 176 Jefferson City, Missouri 65102