ML20217F884

Safety Evaluation Accepting Third 10-yr Inservice Insp Interval Program Plan Requests for Relief for Plant

ML20217F884
Person / Time
Site:	Duane Arnold
Issue date:	03/23/1998
From:	NRC (Affiliation Not Assigned)
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ML20217F881	List: ML20217F877 ML20217F884
References
NUDOCS 9804010216
Download: ML20217F884 (29)

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r NUCLEAR REGULATORY COMMISSION' WASHINGTON, D.C. 30eeHeM

'4,***** SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE THIRD 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN AND ASSOCIATED REQUESTS FOR RELIEF EQB IES UTILITIES INC. DUANE ARNOLD ENERGY CENTER DOCKET NO. 50-331 I

1.0 INTRODUCTION

The Technical Specifications (TS) for the Duane Amold Energy Center, state that the inservice inspection of the American Society of Mechanical Engineers (ASME) Code Class 1,2, and 3 ) components shall be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel (B&PV) Code and applicable addenda as required by 10 CFR 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i). 10 CFR 50.55a(a)(3) states that attematives to the requirements of paragraph (g) may be used, when authorized by the NRC, if (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. Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1,2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the pre-service examination requirements, set forth in the ASME Code, Secthn XI, " Rules for Inservico inspection of Nuclear Power Plant Components," to the extent prat :al 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) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The applicable edition of Section XI of the ASME Code for the current Duane Energy Center, third 10-year inservice inspection (ISI) interval is the 1989 Edition. ~ 9004010216 990323 PDR ADOCK 05000331 G PDR y

2 Pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not practical for its facility, information shall be submitted to the Commission in suppott of that determination and a request made for relief from the ASME Code requirement. After evaluation of the determination, _ pursuant to 10 CFR 50.55a(g)(6)(i), the Commission may grant relief and may impose - alternative requirements that are determined to be authorized by law, will not endanger life, ~ property, or the common defense and security, and are otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed. By letter dated April 26,1996, IES Utilities Inc., (licensee), subn itted its third 10-year interval inservice inspection program plan and associated requests for relief for the Duane Amold Energy Center. The licensee provided additional information in its letters dated September 30, 1996, October 3,1996, October 31,1996, November 26,1996, January 21,1997, and June 26,

1997, 2.0 EVALUATION The staff, with technical assistance from its contractor, the Idaho National Engineering and Environmental Laboratory (INEEL), has evaluated the information provided by the licensee in support of its third 10-year inservice inspection interval program plan and associated requests for relief for Duane Arnold Energy Center. Based on the results of the review, the staff adopts the contractor's conclusions and recommendations presented in the Technical Letter Report (TLR) attached with the exception of Section 4, Conclusion contained in the attached INEEL Technical Evaluation Report regarding Code Case N-535. This was a typographical error, because Code Case N-535 was authorized for use in a separate NRC Safety Evaluation dated January 15,1997.

The Duane Arnold Energy Center Third 10-Year Interval inservice Program Plan, Revision 0 was evaluated for (a) compliance with the appropriate edition / addenda of Section XI, (b) accept;;,bility of examination sample, (c) correctness of the application of system or component examination exclusion criteria, and (d) compliance with ISI-related commitments identified during the NRC's previous reviews. Therefore, based on the review of the Duane Amold Energy Center Third 10-Year interval inservice Program Plan, Revision 0, no deviations from regulatory requirements or commitments were identified by the staff. Request for Relief NDE-R001: Section XI, Examination Category B-A, items B1.11, B1.12, B1.22, B1.30, B1.51, Reactor Vessel Welds. In the licensee's September 30,1996, response to the NRC's request for additional information, the licensee withdrew Request for Relief NDE-R001. ' Request for Relief NDE-R017: Section XI, Table IWB-2500-1, Examination Category B-G-1, item B6.10 requires a 100% surface examination of all reactor vessel closure head nuts. The licensee proposed an attemative in accordance with 10 CFR 50.55a(a)(3)(i), to the Code- . required surface examination of the reactor vessel closure head nuts specified in Table IWB-2500-1. The licensee proposed:

4-3 "As an attemate examination, DAEC will perform a VT-1 visual examination of the surface of all reactor closure head nuts, utilizing the acceptance criteria of IWB-3517, as delineated in the 1989 Addenda of ASME Section XI." The licensee has requested relief from performing the Code-required surface examination of the reactor pressure vessel closure head nuts. As an attemative, the licensee proposes to perform a VT-1 visual examination. All items in Examination Category B-G-1 except the reactor pressure vessel closure head nuts and the closure studs (when removed) require VT-1 visual examinations and volumetric examination (as applicable). Typical conditions that would require corrective action prior to putting closure head nuts back into service would include corrosion, deformed or sheared threads, deformation, and other degradation mechanisms (e.g., boric acid attack). The Code requires a surface examination for closure head nuts. Surface examination procedures are typically qualified for the detection of linear flaws (cracks) and have acceptance criteria for linear flaws only. Acceptance criteria are not provided in the 1989 Edition of the Code, item B6.10, as they were in the course of preparation when the Code was published. Without clearly defined acceptance criteria, conditions that require corrective measures may not be adequately addressed. The 1989 Addenda of Section XI addresses these problems by changing the requirement for the reactor pressure vessel closure head nuts from surface to VT-1 visual examination and providing appropriate acceptance criteria. Article IWB-3000, Acceptance Standards, Section IWB-3517.1, VisualExamination, VT-1, describes conditions for bolting and associated nuts that require corrective action prior to continued service. One of the requirements is to compare crack-like flaws to the flaw standards of IWB-3515 for acceptance. Because the VT-1 visual examination acceptance criteria include evaluation of crack-like indications and other conditions requiring corrective action, such as deformed or sheared threads, localized corrosion, deformation of the part, and other degradation mechanisms, it can be concluded that the VT-1 visual examination provides a more comprehensive assessment of the condition of the closure head nut. As a result, therefore, the staff concludes that the licensee's proposed VT-1 visual examination provides an acceptable level of quality and safety. Based on the comprehensive assessment that the VT-1 visual examination provides, and considering that later editions of the Code require only a VT-1 visual examination of reactor pressure vessel closure head nuts, the staff concluded that an acceptable level of quality and safety is provided by the proposed alternative. Therefore, the licensee's proposed attemative, ] VT-1 visual examination, is authorized pursuant to 10 CFR 50.55a(a)(3)(i). Request for Relief NDE-R022: Section XI, Examination Category B-A, item B1.30, Reactor l . Pressure Vessel Shell-to-Flange Weld. In the licensee's October 3,1996, response to the NRC's request for additional information, the licensee withdrew Request for Relief NDE-R022.

4 Request for Relief NDE-R026: Section XI, Scheduling Requirements for Reactor Pressure Vessel Nozzle-to-Vessel Welds and Nozzle inner Radius Sections. In the licensee's October 31,1996, response to the NRC's request for additional information, the licensee withdrew Request for Relief NDE-R025. Request for Relief NDE-R026: Section XI, Scheduling Requirements for Reactor Pressure Vessel Nozzle-to-Safe End Welds. In the licensee's October 31,1996, response to the NRC's request for additional information, the licensee withdrew Request for Relief NDE-R026. Request for Relief NDE-R006: Section XI, Examination Category B-J, item B9.11, Recirculation Bypass Weld RBA-J007 Code requires 100% vo'umetric and surface examination of Class 1 circumferential pipe welds 4-inch nominal pipe size and greater as defined in Figure IWB-2500-8. The licensee requested Code relief, pursvunt to 10 CFR 50.55a(g)(5)(iii), from performing the volumetric examination to the extent requitad by the Code for Recirculation Bypass Weld RBA-J007. The licensee proposed as an altemative examination the followinf): "As an attemative to existing Section XI requirements, DAEC proposes to perform volumetric examination to the accessible portion of the weld and obtain a total of 85% coverage for this weld length. The examination records specified in Code Case N-460 shall be utilized to identify the reduction in coverage. To perform the additional 15% of weld length draining the Recirculation System would be required, thus increasing exposure to personnel. The benefit of examining the additional 15% has only a small potential of increasing plant safety margins and a disproportionate impact on expenditures of plant manpower and radiation exposure to perform the radiography. "DAEC will examine applicable pressure retaining piping welds to the maximum extent practical within the limitations of the examination technique or design of the component. Should reportable indications be found in the accessible portions of the listed weld, an engineering evaluation will be performed to determine if the inaccessible portion of the weld would be affected. " Subsequent to examination of an affected weld, NDE data sheets will describe in detail, the extent of the limitation and any attemative examination techniques used to obtain coverage. "The inaccessible portions of the weld will continue to be subject to the applicable system pressure test requirements of IWA, and IWB-5000 with a VT-2, visual examination." 1 The Code requires that the subject tee-to-flange weld receive 100% volumetric and surface examinations. The licensee stated that due to the component design only 85% of the required volume can be examined. To perform the complete volumetric examination, design

5 modifications or replacement of the tee-to-flange weld with one of a configuration that provides for complete examination would be required. Imposition of this requirement would cause a considerable burden on the licensee. The licensee's proposed altemative to perform the volumetric examination to the extent practical would result in 85% coverage. Based on the coverage that can be obtained, in combination with the surface examination, the staff concluded that significant degradation, if present, will be detected and the licensee's proposed attemative provides reasonable assurance of structural integrity of the subject components. The staff concluded that examining the Code required volume of the subject tee-to-flange weld is impractical. Considering the percent of the weld that will be examined, and the surface examinations, the staff concluded that significant degradation, if present, will be detected. Therefore, the licensee's proposed attemative provides reasonable assurance of structural integrity of the subject components. Therefore, the licensee's request for relief is granted and the alternative imposed pursuant to 10 CFR 50.55a(g)(6)(i). Request for Relief NDE-R007: Section XI, Table IWB-2500-1, Examination Category B-J, item B9.11 requires 100% volumetric and suiface examination of Class 1 circumferential butt we!ds 4-inch nominal pipe size and greater as defined in Figure IWC-2500-8. The licensee requested Code relief in accordance with 10 CFR 50.55a(g)(5)(iii), from performing the volumetric examination to the extent required by the Code for Recirculation Bypass Weld RSA-J012. The Code requires that the subject valve-to-weldolet weld receive 100% volumetric and surface examinations. The licensee stated that due to the component design only 76% of the required volume can be examined. To perform the complete volumetric examination, design modifications or replacement of the valve-to-weldotet weld with one of a configuration that provides for complete examination would be required. Imposition of this requirement would cause a considerable burden on the licensee. The licensee proposed to perform the volumetric examination to the extent practical, resulting in. 76% coverage. Based on the coverage that can be obtained, in combination with the surface examination, the staff concluded that significant degradation, if present, can be detected. Furthermore, the licensee's proposed alternative provides reasonable assurance of structural integrity of the subject components. The staff concluded that examining the Code-required volume of the subject valve-to-weldolet weld is impractical. Considering the percent of the weld that will be examined, in conjunction with the surface examinations, the staff concluded that significant degradation, if present, will be detected. The staff concluded that the licensee's proposed alternative provides reasonable assurance of structural integrity for the subject components. Therefore, Request for Relief No. NDE-R007 is granted and the alternative imposed pursuant to 10 CFR 50.55a(g)(6)(i). i-

~ 6 Request for Relief NDE-R008: Section XI, Table IWB-2500-1, Examination Category B-F, item B5.130, requires 100% volumetric and surface examination of Class 1 dissimilar metal welds as defined in Figure IWC-2500-8. The licensee requested relief in accordance with 10 CFR 50.55a(g)(5)(iii). The licensee requested relief from performing the volumetric examination to the extent required by Code for Reactor Water Cleanup Weld CUB-F004. The licensee proposed as an alternative examination the following: "As an attemative to existing Section XI requirements, DAEC proposes to perform volumetric examination of 70% of the weld length. DAEC will examine applicable pressure retaining piping welds to the maximum extent practical within the limitations of the examination technique or design of the component. Should reportable indications be found in the accessible portions of the listed weld, an engineering evaluation will be performed to determine if the inaccessible portion of the weld would be affected. " Subsequent to examination of an affected weld, NDE data sheets will describe In detail, the extent of the limitation and any attemative examination techniques used to obtain coverage. "The inaccessible portions of the weld will continue to be subject to the applicable system pressure test requirements of IWA, and IWB-5000 with a VT-2, visual examination." The Code requires that the subject elbow-to-valve weld receive 100% volumetric and surface examinations. The licensee stated that due to the component design only 70% of the required volume can be examined. To perform the complete volumetric examination, design modifications or replacement of the elbow-to-valve weld with one of a configuration that provides for complete examination would be required. Imposition of this requirement would cause a considerable burden on the licensee. The licensee proposed to perform the volumetric examination to the extent practical, resulting in 70% coverage. Based on the coverage that can be obtained, in combination with the surface examination, it can be concluded that significant degradation, if present, would be detected. Therefore, the licensee's proposed alternative provides reasonable assurance of structural integrity of the subject components. The staff concluded that examining the Code-required volume of the subject elbow-to-valve weld is impractical. The staff a'so concluded that considering the percent of the weld that will be examined, in conjunction with the surface examinations, that significant degradation, if present, would be detected. As a result, reasonable assurance of structuralintegrity is provided. Therefore, Request for Relief No. NDE-R008 is granted and the alternative imposed pursuant to 10 CFR 50.55a(g)(6)(i).

7 Request for Relief NDE-R009: Section XI, Table IWB-2500-1, Examination Category B-J, item B9.31, requires 100% volumetric and surface examination of Class 1 branch connection welds 4-inch and larger as defined in Figure IWB-2500-9, -10, or -11 as applicable. The licensee requested relief, pursuant to 10 CFR 50.55a(g)(5)(iii), from performing the volumetric examination to the extent required by the Code for Residual Heat Removal System Weld RHB-J002. The licensee proposed as an alternative examination the following: "As an alternative to existing Section XI requirements, DAEC proposes to perform volumetric examination of 75% of the weld length. DAEC will examine applicable pressure retaining piping welds to the maximum extent practical within the limitations of the examination technique or design of the component. Should reportable indications be found in the accessible portions of the listed weld, an engineering evaluation will be performed to determine if the inaccessible portion of the weld would be affected. " Subsequent to examination of an affected weld, NDE data sheets will describe in detail, the extent of the limitation and any alternative examination techniques used to obtain cove, age. "The inaccessible portions of the weld will continue to be subject to the applicable system pressure test requirements of IWA, and IWB-5000 with a VT-2, visual examination." The Code requires that the subject branch connection weld receive 100% volumetric and surface examinations. The licensee stated that due to the component design only 75% of the required volume can be examined. To perform the complete volumetric examination, design modifications or replacement of the branch connection weid with one of a configuration that provides for complete examination would be required. Imposition of this requirement would cause a considerable burden on the licensee. The licensee proposed to perform the volumetric examination to the extent practical, resulting in 75% coverage. Based on the coverage that can be obtained, in combination with the surface examination, it can be concluded that significant degradation, if present, will be detected. The licensee's proposed alternative provides reasonable assurance of structuralintegrity of the subject components. The staff concluded that examining the Code-required volume of the subject branch connection weld is impractical. Considering the percent of the weld that will be examined, in conjunction with the surface examinations, it can be concluded that significant degradation, if present, will be deter:ted. As a result, reasonable assurance of structuralintegrity is provided. Therefore, Request for Relief No. NDE-R009 is granted and the alternative imposed pursuant to 10 CFR 50.55a(g)(6)(i).

8 Request for Relief NDE-R010: Section XI, Table IWB-2500-1, Examination Category B-J, item B9.11 requires 100% volumetric and surface examination of Class 1 circumferential butt welds as defined in Figure IWC-2500-8. The licensee's requested Code relief pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from performing the volumetric examination to the extent required by the Code for Recirculation Bypass Weld RBB-J006. The licensee proposed as an altemative examination the following: "As an attemative to existing Section XI requirements, DAEC proposes to perform volumetric examination of the 84% weld length. DAEC will examine applicable pressure retaining piping welds to the maximum extent practical within the limitations of the examination technique or design of the component. Should reportable indications be found in the accessible portions of the listed weld, an engineering evaluation will be performed to determine if the inaccessible portion of the weld would be affected. " Subsequent to examination of the affected weld, NDE sheets will describe in detail, the extent of the limitatior; and any alternative examination technique used to obtain coverage. "The inaccessible portions of weld will continue to be subject to the applicable system pressure test requirements of IWA, and IWB-5000 with a VT-2, visual examination." The Code requires that the subject pipe-to-tee weld receive 100% volumetric and surface examinations. The licensee stated that due to the component design only 84% of the required i volume can be examined. To perform the complete volumetric examination, design modifications or replacement of the pipe-to-tee weld with one of a configuration that provides for l complete examination would be required. Imposition of this requirement would cause a considerable burden on the licensee. The licensee proposed to perform the volumetric examination to the extent practical, resulting in 84% coverage. Based on the coverage that can be obtained, in combination with the surface examination, the staff concluded that significant degradation, if present, will be detected. Therefore, the licensee's proposed attemative provides reasonable assurance of structural integrity of the subject components. The Staff concluded that examining the Code-required volume of the subject pipe-to-tee weld is impractical. Also, considering the percent of the weld that will be examined, in conjunction with the surface examinations, the staff concluded that significant degradation, if present, will be detected. The staff concluded that the licensee's proposed alternative provides reasonable assurance of structuralintegrity of the subject components. Therefore, the licensee's Request

9 - for Relief No. NDE-RO10 is granted and altemative imposed pursuant to 10 CFR 50.55a(g)(6)(i). Request for Relief NDE-R023: Section XI, Table IWB-2500-1, Examination Category B-J, items 89.11 and B9.12 require 100% volumetric and surface examination of Class 1 piping circumferential and longitudinal welds 4 inches in diameter and larger as defined by Figure IWB-2500-8. Table IWB-2500-1, Examination Category B-J, item B9.21 requires 100% surface examination of Class 1 piping circumferential welds less than 4 inches in diameter as defined by Figure IWB-2500-9, -10, and -11 as applicable. The licensee requested relief, pursuant to 10 CFR 50.55a(g)(5)(iii), from the Code-required examinations of Class 1 piping welds located in the following containment penetrations: X-7A; X-7B; X-7C; X-7D; X-9A; X-9B; X-16A; X-168; X-11; X 15; X-36; X-12; X-13A; X-138; X-10; X-42; and X-8. The licensee requested relief from the Code-required examination of piping welds located within containment penetrations. The figures provided by the licensee show that the pipe welds within j the penetrations are inaccessible; therefore, the Code-required examinations are impractical. To examine these welds, penetration design modifications or replacement of the piping within the penetration would be required. Imposition of this requirement would cause a considerable I burden on the licensee. As an attemative to the Code requirements, the licensee proposes to perform a VT-2 visual examination in the annular area of each of the subject penetration assemblies each refueling outage in conjunction witti the Class 1 system leakage or hydrostatic test. Based on the proposed attemative, VT-2 wamination of other Category B-J piping welds, it can be concluded that significant degradation, if present, will be detected. As a result, reasonable assurance of operational readiness will be provided. The staff concluded that for the welds within the subject containment penetrations, the Code-required examination is impractical. The licensee's proposed attemative, VT-2 visual examination, and the Code-required examinations being performed on other piping welds, provide assurance that significant degradation, if present, will be detected. The staff concluded that the licensee's proposed alternative provides reasonable assurance of structural integrity for the subject containment penetrations. Therefore, Request for Relief No. NDE-R023 is granted and alternative imposed pursuant to 10 CFR 50.55a(g)(6)(i). Request for Relief NDE-R004: Section XI, Table IWB-2500-1, Exaministion Category B-M-2, item B12.50, Valve Bodies Exceeding NPS 4". This request for relief was originally approved in a NRC Safety Evaluation (SE) dated September 24,1993, during the licensee's second 10-year ISI interval. The SE approved a non-code repair of the "D" outboard main steam isolation valve. As part of the alternative, the licensee stated that radiography of the repaired area would be performed two times ever four successive refueling outages. The first two outages were within the second 10-year interval, and the second two outages fall into the third 10-year interval. Since the alternative approved

10 included the commitment to perform radiography, no new relief is required for the third 10-year interval. Therefore, this request has not been evaluated in this report. Request for Relief NDE-R002: Section XI, Table IWB 25001-1, Examination Category B-K-1, item B10.10, Piping Integrally Welded Attachments. In the licensee's September 30,1996, response to the NRC's request for additional information, the licensee withdrew Request for Relief NDE-R002. Request for Relief NDE-R021: Section XI, Table IWC-2500-1 Examination Category C-B, item C2.21, requires 100% surface and volumetric examination of nonie-to-shell welds as defined by Figure IWC-2500-4(a) or (b), as applicable. These examinations'may be limited to one of multiple vessels or distributed among multiple vessels. The licensee's relief request from the Code requirements pursuant to 10 CFR 50.55a(g)(5)(iii), requested relief from the Code-required volumetric examination of Class 2, Residual Heat Removal heat exchanger nonle-to-shell Weld HEA-CB-2 and proposed as an alternative examination the following: "As an altemative examination, DAEC shall volumetrically examine the accessible 71% of the nozzle to shell weld length, and perform the code required surface examination. DAEC shall also be implementing examination coverage allowed by Code Case N-460." The Code requires 100% surface and volumetric e>. amination of selected Class 2 pressure vessel nozzle-to-shell welds. As shown in the weld examination coverage plot,' complete volumetric examination of the subject weld is impractical due to the nozzle configuration. To examine the required volume, design modifications or replacement of the component with one of a design providing for complete examination is necessary, imposition of this requirement would cause a considerable burden on the licensee. The licensee proposes to perform the volumetric examination to the extent practical, resulting in an estimated 71% coverage of the Code-required examination volume. Based on this examination, in combination w!th the Code-required surface examination and the examination of similar welds, the staff concluded that a pattern of degradation, if present, will be detected. The licensee's proposed alternative provides reasonable assurance of structuralintegrity of the subject components. The staff concluded that the nozzle configuration makes the Code-required examination of Residual Heat Removal Heat Exchanger Nozzle-to-Shell Weld HEA-CB-2 impractical. Based on the estimtted 7.1% of the Code-required volume that will be examined, in combination with the Code-required surface examination, the staff concluded that a pattern of degradation, if present, will be detected.' Therefore, the licensee's proposed alternative provides reasonable 3Coverage plots provided by the licenses are not included with this evaluation. i-j

11 assurance of structuralintegrity of the subject components. Therefore, Request for Relief No. NDE-R021 is granted and the alternative imposed pursuant to 10 CFR 50.55a(g)(6)(i). Request for Relief NDE-R003: Section XI, Table IWC 2500-1, Examination Category C-C, item C3.20, Piping Integrally Welded Attachments. In the licensee's September 30,1996, response to the NRC's request for additional information, the licensee withdrew Request for Relief NDE-R003. Request for Relief NDE-R005: Section XI, Table IWC 2500-1, Examination Category C-C, item C3.10, Integral Attachment Welds. In the licensee's September 30,1996, response to the NRC's request for additional information, the licensee withdrew Request for Relief NDE-R005. Request for Relief PR-002: Section XI, Table IWC-2500-1, Examination Category C-H, items C7.10 through C7.80 require a VT-2 visual examination during system leakage and hydrostatic pressure tests. The licensee proposed the following alternative pursuant to 10 CFR 50.55a(a)(3)(i). The licensee proposed to use the alternative contained in Code Case - N-522 in lieu of the Code-required system leakage and hydrostatic pressure tests for portions of containment penetration piping classified as Code Class 2, when segments of the line, inside and outside of containment, are non-class. The licensee stated: j l "As an alternative to Section XI pressure testing requirements for piping penetrating containment and attached to a nonsafety-related system, DAEC will adopt the provisions of ASME Section XI Code Case N-522. The Appendix J testing is performed by draining the test volume and pressurizing the test volume with air to a pressure of at least P., where P,is the peak calculated containment internal pressure. The test procedure will provide criteria for identification of the source of indicated leakage, including provisions for detection and location of through-wall leakage in CIVs and pipe segments between CIVs. " Pressure testing shall be performed in accordance with the requirements and frequency specified in 10 CFR 50, Appendix J, in lieu of the additional requirements specified in Table IWC-2500-1, Category C-H." l Code Case N-522

• Pressure Testing of Containment Penetration Piping" allows the use of 10 CFR 50.55, Appendix J as an alternative to the rules in Tabie IWC-2500-1, Category C-H, for pressure testing piping that penetrates a containment vessel, when the piping and isolation valves that are part of the containment system are Class 2 but the balance of the piping system is outside the scope of Section XI.

The licensee proposes to use the alternatives contained in Code Case N-522, in lieu of the Code-required pressure tests for portions of the subject lines that are Class 2 at the containment penetration. These segments of lines are part of the containment pressure ' boundary and can be tested in accordance with the containment test criteria found in 10 CFR 50.55a, Appendix J. usu' a

12 Appendix J pressure tests are local leak rate and integrated leak rate tests that verify the leak-tight integrity of the primary reactor containment and of systems and components that penetrate containment.The Appendix J test frequencies provide assurance that the containment pressure boundary is being maintained at an acceptable level while monitoring for deterioration of seals, valves, and piping. The Class 2 containment isolation valves (CIVs) and connecting pipe segments must withstand the peak calculated containment intemal pressure related to the maximum design containment pressure. The. staff finds that the pressure-retaining integrity of the CIVs and connecting piping and their associated safety functions may be verified with an Appendix J, Type C test if it is conducted at the peak calculated containment pressure. The seal between the connecting pipe ' segment and containment may be verified using an Appendix J, Type B test. Therefore, when the connecting pipe segment is subjected to either a Type B or C test, its safety function is verified by the Appendix J test. When air or gas is used as a testing medium, Section XI, - lWC-5210(b) requires that the test procedure include methods for detection and location of through-wall leakage in components being tested. ID.he licensee's test procedure uses air as a testing medium, the procedure needs to meet us requirement. The staff concludes that use of Appendix J testing in accordance with Code Case N-522 is acceptable if the licensee performs the leak test at the peak calculated containment design pressure and that the test procedure provides for detection and location of through-wall leakages in the pipe segmento being tested. The licensee has revised its alternative to include these conditions. Therefore, the licensee's proposed attemative to the Code-required pressure tests, use of alternatives contained in Code Case N-522, is authorized pursuant to 10 CFR 50.55a(a)(3)(i) in that it provides assurance that the containment pressure boundary is maintained while monitoring for deterioration. The use of the alternative is authorized for the current interval or until the Code Case is published in Regulatory Guide 1.147. At that time, if the licensee intends to continue to implement this Code Case, the licensee is to follow all the provisions of the Code Case with limitations issued in Regulatory Guide 1.147, if any. Request for Relief PR-006: Section XI, Table IWC-2500-1, Examination Category C-H, items C7.40 and C7.80 require a VT-2 visual examination during hydrostatic tests of Class 2 systems performed in accordance with IWC-5222 near the end of the interval. IWA-5213 states that for system hydrostatic tests of insulated systems, a 4-hour hold time is required after attaining the test pressure and temperature conditions and before performing the examination; for noninsulated systems or components the hold time is 10 minutes. Pursuant to 10 CFR 50.55a(a)(3)(ii), the licensee proposed an attemative to the Code requirement for a 4-hour hold time prior to performing the VT-2 visual examinations associated with hydrostatic tests of the Class 2 High Pressure Coolant Injection (HPCI) turbine steam system and related turbine auxiliaries, downstream of MO-2202, extending to V-22-16, V-22-19, and CV-2234.

4 6 13 i The licensee stated: "DAEC proposes to implement the attemative rules for 10-year Hydrostatic Testing for class 2 systems as provided in Code Case N-498-1 with the following exception: A system pressure test shall be performed in accordance with IWC- ) 5210(1), [lWA-5211(b)) for the above subject cystem or portion of a system not required to operate during normal reactor operation but for which periodic system or component functional testing is performed to meet the Owner's requirements. This test shall consist of performing the required visual (VT-2) inspections in conjunction with periodic HPCI turbine test performed in accordance with the ASME Section XI Inservice Testing Program. This VT-2 inspection shall be performed once per period rather than once per interval. The ( test hold time shall be a minimum of 30 minutes and a maximum of 60 minutes ] starting when the Technical Specification flow and pressure requirements have 4 been met." Both the Code and Code Case N-498-1 specify pressure tests that include a 4-hour hold time prior to performing the VT-2 visual examination during the hydrostatic test of insulated systems. The licensee has stated that compliance with the 4-hour hold time will result in a burden and I could compromise plant safety. Based on the information provided, the staff concludes that, for the subject system, performing the pressure test with the 4-hour hold time would require the operation of other safety-related systems, creating an operational safety concern. This is because a 4-hour hold time during system operation would cause the torus water temperature to rise above that allowed by the Technical Specifications. Under these test conditions, should an actual plant emergency occur, the additional actions required to bring the plant to a safe shutdown condition could be compromised. The licensee proposed to perform a VT-2 visual examination in conjunction with the System Functional test once each period. The staff concludes that this VT-2 examination, when performed in conjunction with the system functional test (within the maximum temperature range), will ensure the detection of leakage in insulated systems. The staff concludes, that requiring the licensee to comply with the 4-hour hold time for the HPCI system would result in a burden without a compensating increase in the level of quality and safety. The licensee stated that tests at operating pressure are performed each period. During these tests, the operating pressure is maintained for up to one hour for performance of the functional test. The staff concludes that performing the VT-2 visual examination with the system at normal operating pressure within the allowable temperature range should ensure that leakage will be detected, providing reasonable assurance of operational readiness of the subject systems. Therefore, the licensee's proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(ii). Request for Relief PR-007: Section XI, Table IWC-2500-1, Examination Category C-H, items C7.40 and C7.80 require a VT-2 visual examination during hydrostatic tests of Class 2 systems performed in accordance with IWC-5222 near the end of the interval. lWA-5213 states that, for system hydrostatic tests of insulated systems, a 4-hour hold time is required after attaining the test pressure and temperature conditions and before performing the examination; for noninsulated systems or components the hold time is 10 minutes. a

4 14 Pursuant to 10 CFR 50.55a(a)(3)(ii) the licensee proposed an attemative in leu of the Code requirement to perform a 4-hour hold time prior to the VT-2 visual examinations associated with hydrostatic tests of the Class 2 High Pressure Coolant Injection (HPCI) system piping and components on the water side, downstream of MO-2321 and MO-2300, extending to MO-2312, CV-2315, and MO-2318 as follows: "DAEC proposes to implement the altemative rules for 10-year Hydrostatic - Testing for class 2 systems as provided in Code Case N-498-1 with the following exception: A system pressure test shall be performed in accordance with IWC-5210(1), [lWA-5211(b)] for the above subject system or portion of a system not required to operate during normal reactor operation but for which periodic system or component functional testing is performed to meet the Owner's requirements. This test shall consist of performing the required visual (VT-2) inspections in conjunction with periodic HPCI turbine test performed in accordance with the ASME Section XI Inservice Testing Program.. This VT-2 inspection shall be performed once per period rather than once per interval. The test hold time shall be a minimum of 30 minutes and a maximum of 60 minutes starting when the Technical Specification flow and pressure requirements have been met." Both the Code and Code Case N-498-1 specify pressure tests that include a 4-hour hold time prior to performing the VT-2 visual examination during the hydrostatic test of insulated systems. The licensee has stated that compliance with the 4-hour hold time will result in a burden and could compromise plant safety. Based on the information provided, the staff believes that, for the subject system, performing the pressure test with the 4-hour hold time would require the operation of other safety-related systems, creating an operational safety concem. This is because a 4-hour hold time during system operation would cause the torus water temperature to rise above that allowed by the Technical Specifications. Under these test conditions, should an actual plant emergency occur, the additional actions required to bring the plant to a safe shutdown condition could be compromised. The licensee proposed to perform a VT-2 visual examination in conjunction with the System Functional test once each period. The staff concludes that this VT-2 examination, when performed in conjunction with the system functional test (within the maximum temperature range), will ensure the detection.of leakage in insulated systems. For the HPCI system, requiring the licensee to comply with the 4-hour hold time would result in a burden without a compensating increase in the level of quality and safety. The licensee stated that tests at operating pressure are performed each period. During these tests, the operating pressure is maintained for up to one hour for performance of the functional test. The staff concludes that performing the VT-2 visual examination with the system at normal operating pressure within the allowable temperature range should ensure that leakage will be detected and thus provide reasonable assurance of operational readiness. Therefore, the licensee's proposed alternative is authorized pursuant to 10 CFR 50.55a(s)(3)(ii).

4 15 Request for Relief PR-005: Section XI, Table IWD-2500-1, Examination Category D-A, item D2.10 requires a system pressure test and/or a system hydrostatic test be performed. For safety or relief valve piping that discharges into the containment pressure suppression pool, IWD-5223(f) states that a pneumatic test (at a pressure of 90% of the pipe submergence head of water) that demonstrates leakage integrity shall be performed in lieu of a system hydrostatic ' test. Pursuant to 10 CFR 50.55a(a)(3)(ii), the licensee proposed an attemative to the hydrostatic pressure test requirements for safety or relief discharge piping. The licensee proposed: "In accordance with DAEC Technical Specifications during normal plant operations, each relief valve is manually opened with the reactor pressure >100 psig. Relief valve tailpipe and discharge piping momentarily experiences a discharge pressure of about 25 psi. Tailpipe pressure, temperature and suppression pool temperatures are monitored as necessary. The DAEC will ensure discharge piping integrity through normal plant startup operations. In addition, the DAEC will perform a VT-3 visua! examination of the six discharge lines every interval to provide additional assurance of discharge piping integrity. 'With the pressures (2.2 psi) currently required by Section XI, elevated pressure hydrostatic tests do not offer a commensurate increase in safety with cost benefit and places an undo burden upon a licensee to perform these tests." The Code requires that a pneumatic test that demonstrates leakage integrity be performed in lieu of a system hydrostatic test for safety or relief valve piping that discharges into the containment pressure suppression pool; the test pressure is to be 90% of the pressure of the pipe submergence head of water. Submergence head pressure for the subject piping is approximately 2.2 psig. The staff believes that performing a pressure test at 2.2 psig when the piping operates at a pressure of 25 psig does not demonstrate the operational readiness of the subject piping. In addition, to perform the pneumatic pressure test, assembly and disassembly of scaffolding in radiation areas would be required. It is noted that later editions of the Code (1992 Addenda) have exempted hydrostatic testing for open-ended portions of discharge lines beyond the last shutoff valve and open-ended safety or relief valve discharge lines, including safety or relief valve piping which discharges in the containment pressure suppression pool. Based on a recent failure of discharge piping at another plant, the licensee modified the - alternative to include performance of a VT-3 examination of the six discharge lines every Interval to provide additional assurance of discharge piping integrity. The staff concluded that i requiring the licensee to perform a pneumatic test on the discharge piping to the suppression pool at a test pressure of only 2.2 psig results in a burden without compensating increase in i quality and safety. The licensee's proposed alternative as modified includes performance of a . VT-3 on the subject system and components and provides reasonable assurance of operational readiness of the safety or relief valve piping that discharge into the containment pressure pool. 1 't

16 Therefore, the licensee's proposed attemative is authorized pursuant to 10 CFR 50.55a(a)(3)fi). Request for Relief PR 003: The Code requires system hydrostatic testing once per 10-year interval at or near the end of the interval. These requirements are contained in Tabie f IWB-2500-1, Category B-E, items B4.11, B4.12, and B4.13, and Category B-P, items B15.11, B15.51, B15.61, and B15.71 (for Class 1 systems); Table IWC-2500-1, Category C-H, items C7.20, C7.40, C7.60, ar.d C7.80 (for Class 2); and Table IWD-2500-1, Categories D-A, D-B, and D-C, items D1.10, D2.10, and D3.10 (for Class 3). The licensee proposed as an attemative to the Code requirements pursuant to 10 CFR 50.55a(a)(3)(ii), to use the attematives contained in Code Case N-498-1 in lieu of the ASME Section XI hydrostatic test requirements for Code Class 1,2, and 3 systems. The licensee stated: "As an alternative to existing Section Xl requirements, DAEC will adopt the provisions of Code Case N-498-1, "In lieu of performing a hydrostatic pressure test at a pressure above nominal operating pressure or system pressure for which overpressure protection is required, as required by Table IWA-5210-1, Examination Categories B-E, B-P, C-B, C-H, D-A, D-B, and D-C, a system pressure test at nominal operating pressure and temperature shall be performed. "In lieu of instrumentation requirements specified in IWA-5260, existing plant instrumentation will be used per IWA-5212(b). Where gauging may be required and does not exist, the rules of IWA-5260 shall be used. For Class 3 Systems, DAEC shall also continue to maintain and implement an erosion / corrosion monitoring program for piping determined to be most susceptible to erosion and corrosion, as previously described." The Code requires a system hydrostatic test to be performed once per interval in accordance with lWA-5000 for Class 1,2, and 3 pressure-retaining systems. The licensee proposes to. implement the alternatives to Code requirements contained in Code Case N-498-1, Altemative Rules for 10-Year System Hydrostatic Testing for Class 1, 2, and 3 Systems, dated May 11,1994. The system hydrostatic test stipulated in Section XI is not a test of the structural integrity but rather an enhanced leakage test.8 Hydrostatic testing only subjects the piping to a small i increase in pressure over the design pressure; therefore, piping dead weight, thermal expansion, and seismic loads present far greater challenges to the structural integrity of the I S. H. Bash and R. R. Maccary, " Development ofh. Service Inspection Safety Philosophyfor U.Sk Nuclear Pour Plants." ASME,197I.

c s 17 system. Consequently, the Section XI hydrostatic pressure test is primarily regarded as a . means to enhance leak detection during the examination of components under pressure, rather than as a method to determine the structural integrity of the components. In addition, the industry experience indicates that leaks are not being discovered as a result of hydrostatic test pressures causing a preexisting flaw to propagate through the wall. In most cases, leaks are being found when the system is at normal operating pressure. In lieu of 10-year hydrostatic pressure testing at or near the end of the 10-year interval, Code Case N-498-1 requires a VT-2 visual examination at nominal operating pressure and temperature in conjunction with a system leakage test performed in accordance with Paragraph IWA-5000 of the 1992 Edition of Section XI. The requirements of Code Case N-498-1 for Class 1 and 2 systems are the same as those of Code Case N-498, Alternative Rules for 10-Year System Hydrostatic Testing for Class 1 and 2 Systems, which was previously approved for . general use on Class 1 and 2 systems in Regulatory Guide 1.147, Rev. 9. For Class 3 syrtems, N-498-1 specifies requirements identical to those for Class 2 components. Class 3 systems do not normally receive the amount and/or type of nondestructive examinations that Class 1 and 2 systems receive. While Class 1 and 2 system failures are relatively uncommon, Class 3 leaks occur more frequently and are caused by different failure mechanisms. Based on a review of Class 3 system failures requiring repair during the last 5 years,8 the most common causes of failure are erosion-corrosion (EC), microbiologically-I induced corrosion (MIC), and general corrosion. In general, licensees have implemented programs for the prevention, detection, and evaluation of EC and MIC; therefore, Class 3 systems receive inspections commensurate with their functions and expected failure mechanisms. System hydrostatic testing entails considerable time and radiation dose. The safety assurance provided by the enhanced leakage detection gained frorn a slight increase in system pressure during a hydrostatic test may be of,' set or negated by the necessity to gag or remove safety and/or relief valves (placing the system, and thus the plant, in an off-normal state), erect temporary supports in steam lines, and expend resources to set up testing with special ) equipment and gages. Therefore, performance of system hydrostatic testing represents a considerable burden. Considering the minimalincrease in assurance of structuralintegrity provided by the increased pressure associated with a hydrostatic test (versus the pressure for the system leakage test), the hardship associated with performing the hydrostatic test, and the assurance of structural integrity provided by the alterative, the staff finds that compliance with the Section XI hydrostatic testing requirements results in hardship and/or unusual difficulty without a compensating increase in the level of quality and safety. The staff concluded that compliance with the Cade's hydrostatic testing requirements results in hardship and/or unusual difficulty without a es gensating increase in the level of quality and safety.- Performing the hydrostatic pressure test in accordance with Code Case N-498-1 3 Documented in Licensee Event Reports and the Nuclear Plant Reliability Data System databases.

18 provides reasonable assurance of the structural integrity of the subject systems and components. Therefore, the licensee's proposed altemative, to implement the pressure test rules of Code Case N-498-1 for Code Class 1,2, and 3, is authorized for DAEC, pursuant to 10 CFR 50.55a(a)(3)(ii). This alternative is authorized for the current interval or until such time as this code case is published in Regulatory Guide 1.147. At that time, if the licensee intends to continue to implement this code case, the licensee is to follow all provisions in Code Case N-498-1, with limitations issued in Regulatory Guide 1.147, if any. Request for Relief PR-004: IWA-4700(a) and (b), Altemative Pressure Test Requirements for Code Class 1, Class 2, and Class 3 Systems Following Repair, Replacements and Modifications Code Requirement-lWA-4700(a), Pressure Test, requires that after repair by. welding on the pressure-retaining boundary, a system hydrostatic test shall be performed in accordance with IWA-5000. lWA-5214, Repairs and Replacements, requires that a component repair or replacement shall

be pressure tested prior to resumption of service if required by IWA-4400 and IWA-4600.

The test pressure and temperature for a system hydrostatic test subsequent to the component repair or replacement shall comply with the system test pressure and temperature specified in IWB-5222, IWC-5222, and IWD-5223, as applicable to the system that contains the repaired or replaced component. Tu licensee proposed an alternative to Code requirements pursuant to 10 CFR 50.55a(a)(3)(ii), regarding hydrostatic testing requirements following repairs, replacements, and modifications on Code Class 1, Class 2, and Class 3 systems. The licensee proposed: "DAEC proposes to perform pressure testing on Class 1,2, and 3 repaired / replaced components ia accordance with the requirements of ASME Section XI Code Case N-416-1. This Code Case offers an acceptable attemative to Section XI requirements. In addition to the NDE requirements of the Code Case, DAEC will also perform a surface examination of the root pass layer of repair / replacement weld on Class 3 components in accordance with the NDE requirements of ASME Section Ill. 'With the pressures currently required by Section XI, elevated pressure hydrostatic tests do not offer a commensurate increase in safety with cost benefit and places undo burden upon a licensee to perform these tests." The Code requires a system hydrostatic test to be performed, in accordance with IWA-5000, after repairs by welding on the pressure-retaining boundary. Hardships are generally encountered during hydrostatic testing in accordance with Code specifications. For example, because hydrostatic test pressures are higher than nominal operating pressures, these tests frequently require significant effort to set up and perform and may require special equipment,

e 19 such as temporary pumps and gauges, or unique valve lineups. The licensee proposes to implement the alternative to these tests contained in Code Case N-416-1 for Class 1,2, and 3 components. For Class 3 repair / replacement welds or welded areas, the licensee will supplement the pressure test with a surface examination on the root pass layer. Code Case N-416-1 specifies examination of welded repairs / replacements in accordance with the applicable subsection of the 1992 Edition of Section 111. This Code Case also allows the VT-2 visual examination to be performed at nominal operating pressure and temperature in conjunction with a system leakage test, in accordance with Paragraph IWA-5000 of the 1992 Edition of Section XI. The 1989 Editions of Sections lll and XI are the latest Code editions referenced in 10 CFR 50.55a. Comparison of the system pressure test requirements of the 1992 Edition of Section XI with those of the 1989 Edition show that: the test frequencies and the pressure conditions associated with these tests have not changed; the hold times have either remained unchanged or increased; the terminology associated with the system pressure test requirements for all three Code classes has been clarified and streamlined; and the nondestructive examination (NDE) requirements for welded repairs remain the same. Hydrostatic testing subjects the piping components to only a small increase in pressure over the design pressure and, therefore, does not present a significant challenge to the integrity of the pressure boundary. Accordingly, hydrostatic pressure testing is primarily a means of enhancing leak detection, rather than a measure of structuralintegrity. Depending on wall thickness, the Code requires volumetric examination of repair or replacement welds in Code Class 1 and 2 piping components, but only a surface examination of the final weld pass for Code Class 3 components. The only ongoing NDE requirement for Code Class 3 components is a VT-2 visual examination for leaks in conjunction with the 10-year hydrostatic tests and the periodic pressure tests. Considering the examinations of Code Class 1 and 2 systems and that hydrostatic pressure tests rarely result in pressure boundary leaks that would not occur during system leakage tests, the staff finds that the increased assurance of the integrity of Class 1 and 2 welds is not commensurate with the burden of performing hydrostatic testing. For Class 3 welds, the added assurance provided by a hydrostatic test is not commensurate with the burden of performing hydrostatic testing when, during the repair process, a surface examination is performed on the root pass layer of butt and socket welds, and a system pressure test is performed after the repair.

) e - 20 l For welded repairs or replacements of Code Class 1,2, and 3 components, compliance with the ) hydrostatic testing requirements of the Code would result in hardship without a compensating increase in the level of quality and safety. The licensee has proposed to implement the alternatives to Code requirements contained in Code Case N-416-1, including surface examination of the root pass layer of butt and socket welds in welded repairs. The staff. concluded that the licensee's proposed alternative provides a reasonable assurance of the structural integrity of the subject components. Therefore, the alternative is authorized, pursuant to 10 CFR 50.55a(s)(3)(ii). Use of Code Case N-416-1, with a surface examination on the root pass layer of Class 3 repair / replacement welds or welded areas, is authorized for the second 10-year ISI program or until such time as the Code Case is published in Regulatory Guide 1.147. At that time, if the licensee intends to continue to implement this Code Case, the licensee should follow all provisions in Code Case N-416-1, with limitations issued in Regulatory Guide 1.147,if any. . Request for Relief NDE-R011: Section XI, lWA-2232, Ultrasonic Examination, requires that ultrasonic calibration blocks meet the design criteria of ASME, Section XI, Appendix 1, Article 12100, Appendix 1, Supplement 4, and Section V, Article 4, as applicable. The licensee proposed an alternative to the Code requirements pursuant to 10 CFR 50.55a(a)(3)(i), to the calibration block reflector requirements of the Code, as follows: " Future calibration blocks will meet the design, fabrication, and material specification requirements of ASME Section XI Appendix 1, Ill, and Article 4 and 5 of ASME Section V, and will be provided with the documentation necessary to demonstrate compliance with these requirements. Additionally, when existing calibration blocks that lack certain design requirements or appropriate documentation, action will be taken to provide adequate assurance that the blocks will establish the proper calibration and sensitivity, and a comparison will be made between the attenuation of the calibration block and material being examined. "A demonstration was conducted to verify that the vessel calibration block IE-30 is compatible with ultrasonic equipment that will be utilized for the vessel examination. The results were found to be acceptable under the 1989 Section XI requirements and will be documented under IWA-2240 requirements. A comparison with the sensitivity obtained from an ASME standard block and the DAEC IE-30 block showed that the DAEC calibration was slightly more sensitive." The Code requires that calibration blocks be of the same diameter, thickness, and material as the area to be examined. Section V, Article 4, specifies that each vessel calibration block have 3-inch deep, side-drilled hole reflectors at 1/4T,1/2T,3/4T, and have milled notches on the surfaces corresponding to the inside and outside of the vessel. The licensee procured its -

21 vessel calibration block, IE-30, when the plant was built. This block satisfies the 1989 Code requirements with the exception of two side-drilled holes. To address the NRC's concem regarding examination sensitivity when calibration is done using - this block, the licensee provided a General Electric Nuclear Energy report that addresses examination sensitivity and calibration using both the existing block and one meeting the Code requirements. The report discusses theoretical and empirical information on the " edge effect" of the reflectors and concludes that angle beam calibration on the existing block, with 1%-inch deep side-drilled holes, results in a slightly higher calibration sensitivity than would be obtained on the Code-required 3-inch deep, side-drilled hole reflectors. . Because the licensee is able to establish a distance amplitude curve with the existing block that provides an examination sensitivity equal to or greater than that obtained from a block with the Code-required 3-inch deep side-drilled hole reflectors, the sensitivity will provide an acceptable level of quality and safety. In addition, the licensee verified that calibration block IE-30 is compatible with the ultrasonic equipment to be used for future RPV examinations. The staff concluded that continued use of the existing DAEC calibration block, IE-30, provides an acceptable level of quality and safety. In addition, the licensee has stated that new calibration blocks will be designed to meet Code requirements. Therefore, the licensee's proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i). Request for Relief NDE-R014: Section XI, Appendix ill, lll-3430, specifies requirements for reflectors placed in calibration blocks. The licensee proposed an alternative to the Code requirements pursuant to 10 CFR 50.55a(a)(3)(i), to the calibration block reflector requirements specified in Appendix ill. The licensee proposed: "Duane Arnold Energy Center requests relief from the ASME Section XI, Appendix ill requirements for calibration block notch dimensions, in order to allow the continued use of the existing calibration blocks as supported by Reg. Guide 1.150. All future calibration blocks will be designed and fabricated to the requirements of Appendix ill of the 1989 Edition of ASME Section XI." The Code requires that calibration blocks be of the same diameter, thickness, and material as the area to be examined; Appendix ill give the specifications for placing reflectors in these blocks. The licensee procured its calibration blocks at the time the plant was built and has used them during previous inservice inspection intervals. Based on a review of their specifications, it appears that an acceptable level of equivalency exists. For the calibration blocks with notches slightly shorter than the 1 inch required by the Code, the staff concurs that there is probably little or no effect on the sensitivity of the examination. The calibration blocks with notches slightly shallower than required by the Code would likely provide an examination sensitivity equal to or better than that of a calibration on deeper notches. For the calibration blocks with notches less than 1.5 inches from the edge of the block, it is expected that there is little effect on the calibration sensitivity. For calibration block IE-18, the 1

22 licensee noted that the notch is outside the 10% depth tolerance by +0.0046 inch; the licensee compared responses from this notch and a Code-compliant notch and verified that insignificant amplitude differences result. Although the existing calibration blocks do not comply with the 1989 Appendix lil requirements, use of current designs would result in insignificant differences in examination sensitivities. Therefore, the existing calibration blocks will provide an acceptable level of quality and safety. The licensee procured the existing calibration blocks when the plant was built and has used them during previous inservice inspection intervals. Based on a review of the calibration block specifications, the staff concludes that existing blocks provide an acceptable level of quality and safety. Therefore, the licensee's proposed altemative, use of existing calibration blocks, is authorized pursuant to 10 CFR 50.55a(s)(3)(i). Request for Relief NDE-R012: Section XI, Table IWB-2500-1, Examination Category B-J, item B9.12 requires surface and volumetric examinations of longitudinal piping welds 4-inch nominal pipe size and larger, as defined in Figure IWB-2500-8. These examinations are performed in conjunction with those of the circumferential welds selected for examination. The length of longitudinal welds required to be examined is at least one pipe diameter, but not more than 12 inches, from the circumferential weld intersection point. Examination Categories C-F-1 and C-F-2, items C5.12, C5.22, C5.52, and C5.62 require volumetric and surface examinations of longitudinal piping welds in Class 2 piping to be performed in conjunction with those of circumferential welds selected for examination, as defined in Figure IWC-2500-7. At least 2.5t of longitudinal weld is required to be examined. For items C5.42 and C5.82, a surface examhation is required for longitudinal piping welds intersecting circumferential welds selected for examination, as defined in Figure IWC-2500-7. At least 2.5t of the longitudinal weld is required to be examined. The licensee proposed as an alternative to the Code requirements in accordance with 10 CFR 50.55a(a)(3)(i), to use the attematives contained in Code Case N-524 in lieu of the volumetric and/or surface examination for the length of longitudinal piping welds required to be examined in accordance with Tables IWB-2500 and IWC-2500. The licensee proposed: "DAEC proposes as an alternative to the Code required volumetric examination and/or surface examination of Class 1 and 2 longitudinal pipe welds, to perform the examinations in accordance with ASME Section XI Code Case N-524 (draft), " Alternative Examination Requirements for Longitudinal Pipe Welds in Class 1 and 2 Piping; Section XI, Division 1, which states: '(a) When only a surface examination is required, examination of the longitudinal piping welds is not required beyond those portions of the welds within the examination boundaries of intersecting circumferential welds.

23 '(b) When both surface and volumetric examinations are required, examination of the longitudinal piping welds is not required beyond those portions of the welds within the examination boundaries of the intersecting circumferential welds provided the following requirements are met: '(1)' Where longitudinal welds are specified and locations are known, examination requirements shall be met for both transverse and parallel flaws at the intersection of the welds and for that length of the longitudinal weld within the circumferential weld examination volume. '(2) Where longitudinal welds are specified but locations are unknown, or the existence of longitudinal welds is uncertain, the examination requirements l shall be met for both transverse and parallel flaws within the entire examination volume of the intersecting circumferential welds.'" The Code specifies the length of longitudinal weld, measured from the intersection with the circumferential weld, that must be examined. The licensee's proposed alternative is to examine only the portions of the longitudinal weld contained within the examination area of the intersecting circumferential weld. This altemative is contained in Code Case N-524, Altemative { Examination Requirements for Longitudinal Welds in Class 1 and Class 2 Piping. Longitudinal welds are produced during the manufacture of the piping, not in the field like i circumferential welds. Consequently, longitudinal welds are fabricated under the strict guidelines specified by the manufacturing standard, which provides assurance of structural integrity. These welds were also subjected to preservice and initial inservice examinations, which provide additional assurance of structuralintegrity. No significant loading conditions or material degradation mechanisms have become evident that spec lfically relate to longitudinal seam welds in nuclear plant piping. Since the most critical region of the longitudinal weld is that portion that intersects the circumferential weld, which will be examined during the examination of the circumferential weld, the licensee's alternative provides an acceptable level of quality and safety. The licensee's proposed attemative includes the examination of the most critica! portions of the longitudinal welds. Therefore, use of Code Case N-524 is authorized pursuant to 10 CFR 50.55a(a)(3)(i). Use of Code Case N-524 is authorized for the current interval or until such time as the Code Case is published in Regulatory Guide 1.147. At that time, if the licensee intends to continue to implement this code case, the licensee is to follow all the provisions in Code Case,N-524 with limitations issued in Regulatory Guide 1.147, if any. - Request for Relief NDE-R013: Paragraph IWB-2430, Expansion Criteria for Welds Govemed by Generic Letter 88-01 and NUREG-0313, Rev. 2 requires that: (a) Additional examinations shall be performed during the current outage when indications exceed the acceptance standards of Table IWB-3410-1. The additional

24 examinations shall include the remaining welds, areas, or parts included in the inspection item listing and scheduled for this and the subsequent period. -(b) If the additional examinations required above reveal indications exceeding the acceptance standards of Table IWB-3410-1, the examinations shall be further extended to include additional examinations at this outage. The additional examinations shall include all the welds, areas, or parts of similar design, size, and function. (c) For the inspection period following the period in which the examinations of (a) or (b) above were completed, the examinations shall be performed as normally scheduled in accordance with IWB-2400. The licensee has proposed an alternative, pursuant to 10 CFR 50.55a(a)(3)(i), to the additional examination requirements of IWB-2430 for all full-penetration circumferential and branch pipe connection welds in austenitic stainless steel piping that are nominal pipe size 4 inches or larger and contain reactor coolant at a temperature greater than 200*F during power operation. The licensee proposed: "In instances when examinations are being performed to meet Generic Letter 88-01, and also applied to the percentages required by ASME Section XI, DAEC will perform sample expansions as required by Generic Letter 88-01 and i NUREG-0313, Rev. 2 should unacceptable IGSCC flaw indications be identified in the welds. The expanded sample will be examined utilizing the volumetric and surface examination techniques." The Code states that examinations that reveal indications exceeding acceptance standards shall be extended to the remaining welds, areas, or parts included in the inspection item listing and scheduled for examination during this and the subsequent period. The licenses has requested to use the sample expansion criteria of NUREG-0313 to identify additional examination areas. NUREG-0313 states that an additional sample of welds in the appropriate category (Categories A, B, or C) should be inspected. The additional sample should be similar in distribution (pipe size, system, and location) to the original sample and approximately equalin number. The NUREG-0313 sample expansion methodology is a systematic approach to determining potential failure trends that selects samples from components with similar characteristics. In addition, the NUREG-0313 scheduling criteria essentially double the number of welds recM.ing volumetric examination during the 10-year interval for those welds susceptible to IGSCC. Selecting more vulnerable welds tends to offset any reduction in additional examinations, relative to Code n3quirements, that may occur if IGSCC is identified. The staff concluded that the licensee's proposed alternative provides an acceptable level of quality and safety, because the additional examination areas selected will more closely

4 ~ w 25 resemble the welds where IGSCC was detected. Therefore, the licensee's proposed attemative - is authorized pursuant to 10 CFR 50.55a(s)(3)(l). Request for Relief NDE-R015: The Code, Section XI, IWX-4000 provides the rules and requirements for repair of pressure-retaining Class 1, 2, and 3 components and their supports, and for the attachment of replacements to the system by welding or brazing. Section XI, lWX-7000 provides the rules and requirements for procurement and construction of items to be used for replacement. The licensee proposed an attemative, pursuant to 10 CFR 50.55a(s)(3)(i), to the 1989 Edition Code requirements for IWX 4000 and IWX-7000. The licensee proposed "DAEC will use the 1989 Edition of ASME Section XI, as amended by the 1989 Addenda, to govem Repair Procedures (IWX-4000) and Replacements (lWX-7000)." The licensee requested relief to implement the 1989 Addenda of Section XI to gcVem repair and replacement procedures. Addenda to the Code typically provide enhancements or clarification of existing Code requirements. The staff concludes that the changes incorporated by the 1989 Addenda enhance and/or clarify the intent of the rules for repair and replacement programs and plans. The changes do not alter the technical content of the Code rules. Therefore, the staff concludes that the 1989 Addenda provides an acceptable level of quality and safety. Therefore, the licensee's proposed attemative, to use the 1989 Addenda, is authorized pursuant to 10 CFR 50.55a(s)(3)(i). Request for Relief NDE-R016: ASME Code, Section XI, IWB-2420 and IWC-2420, Successive Examinations of Class 1 and 2 Vessels. In the licensee's September 30,1996, response to the NRC's request for additional information, the licensee withdrew Request for Relief NDE-RO16. Request for Relief NDE-R018: ASME Code, Section XI, Examination Category B-K-1, items B10.10 and B10.20 require a volumetric or surface examination of integrally-welded attachments as defined by Figures IWB-2500-13,-14, or-15, as applicable. Examination Category C-C, items C3.10, and C3.20 require surface examination as defineo by Figure IWC-2500-5. Examination Category D-A, D-B, and D-C; Items D1.20 through D1.60, D2.20 through D2.60, and D3.20 through D3.60 require VT-3 visual examination as defined by Figure IWD-2500-1. The licensee proposed an alternative, under 10 CFR 50.55a(a)(3)(i), to use the attematives contained in Code Case N-509 in lieu of the Code requirements associated with the selection and examination of integrally-welded attachments. The licensee stated: "In lieu of performing the Code required examinations, DAEC proposes to examine integrally welded attachments in accordance with Code Case N-509 requirements. The 10% sample and selection of the nonexempt integrally

A w => 26 welded attachments are designated in Technical Approach and Position TAP-1007." in lieu of Code requirements for selection and examination of integral attachment welds, the licensee proposes to apply alternatives contained in Code Case N-509, Attemative Rules forthe Selection and Examination *of Class 1, 2, and 3 Integrally Welded Attachments. In addition, the licenece has committed to examine a 10% sample of all nonexempt integrally-welded - attachments to piping, pumps, and valves in Class 1,2, and 3 systems. The licensee's approach to implementing Code Case N-509 is documented in their Technical Approach and Position (TAP)-1007. This TAP contains a table that includes the total number of nonexampt integrally-welded attachments for each item number and the 10% sample selected. Many of the Code examination requirements are based on sampling to assure that service-related degradation is not occurring. The licensee's proposed sample of a minimum of 10% of - all integral attachment welds in Code Class 1,2, and 3 systems, will provide assurance that degradation, if occurring, will be detected. Therefore, the use of the attematives contained in Code Case N-509, with a minimum 10% selection of a!I integrally-welded attachments in each Code Class, provides an acceptable level of quality and safety. The licensee has proposed to examine integral attachments in accordance with Code Case N-509, with a minimum 10% selection of all nonexempt Code Class 1,2, and 3 integrally-welded attachments to piping, pumps, and valves. In addition, the licensee will ensure that its proposed 10% sample of all the nonexempt integral welded attachments are uniformly distributed in each piping system of DAEC's Class 1,2, and 3 systems and components as indicated in their Technical Approach and Position numbered TAP-1007, which is contained in the April 26,1996 submittal. The staff concludes that the licensee's proposed altemative provides an acceptable level of quality and safety in that it will provide assurance of structural . integrity. Therefore, the licensee's proposed alternative to use Code Case N-509, and proposed sample of a minimum of 10% of all integral attachment welds in Code Class 1,2, and 3 systems is authorized pursuant to 10 CFR 50.55a(a)(3)(i). Use of alternatives contained in Code Case N-509, with the selection provision noted above, is authorized for the current interval or until such time as the Code Case is published in Regulatory Guide 1.147. At that time, if the licensee intends to continue to implement this code case, the licensee should follow all provisions in Code Case N-509, with limitations issued in Regulatory Guide 1.147, if any. Request for Relief NDE-R019: ASME Code Class 1 and 2, Integrally Welded Attachments. In the licensee's September 30,1996, response to the NRC's request for additional information, the licensee withdrew Request for Relief NDE-RO19. Request for Relief NDE-R020: IWF-5000, inservice inspection Requirements for Snubbers. This request for relief is outside the scope of this review and is be'@ evaluated in a separate report by the NRC. l

,, e 27 Request for Relief NDE-R024: IWA-2430(d), inspection Intervals in the licensee's October 31, 1996, response to the NRC's request for additional information, the licensee withdrew Request for Relief NDE-R024. Request for Relief PR-001: ASME Code, Section XI, IWA-5250(a)(2) requires that the source of leakage detected during a system pressure test be located and evaluated by the Owner for' corrective action. When the leakage is at a bolted connection, the bolting shall be removed, VT-3 visually examined for degradation, and evaluated in accordance with IWA-3100. The licensee proposed an attemative, pursuant to 10 CFR 50.55a(a)(3)(i), to the ASME Section XI requirements for removal of bolting at leaking connections for VT-3 visual examination. The licensee proposed the following: "If leakage occurs at a bolted connection, during the performance of a system pressure test, an engineering evaluation shall be performed to determine if the associated bolting is susceptible to corrosion which could result in further degradation and increased leakage. This evaluation shall address at a minimum:

1) type and location ofleakage

2) historicalleakage

3) bolting material and its resistance to corrosion by leaking medium

4) visual evidence of corrosion

5) history of bolting material degradation, due to corrosion, in a similar environment "If the engineering evaluation indicates that the bolting material is not susceptible i

to corrosion, then bolt removal for visual examination and further evaluation shall not be required. However, termination of leakage shall be addressed and corrective measures taken as necessary. "If the evaluation determines the need for a VT-3 visual examination of the bolting, one bolt closest to the source of leakage shall be removed, and in lieu of performing the Code required VT-3 visual examination of tne bolting will be VT-1 visually examined per IWA-2211(a) and evaluated in accordance with IWB-3517.1. If the removed bolt has evidenco of degradation, all remaining bolting shall be removed and VT-1 examined and evaluated accordingly. All examinations shall be traceable to the VT-2 documentation originally detecting the leakage and applicable records will be maintained per IWA-6000." In accordance with the 1989 Edition of the Code, when leakage occurs at bolted connections, all bolting is required to be removed for VT-3 visual examination, in lieu of this, the licensee has proposed to evaluate the bolting to determine its susceptibility to corrosion. The staff has reviewed the licensee's submittal and concludes that the evaluation process proposed by the licensee provides a sound engineering approach. This evaluation considers a number of parameters, including bolting materials, the potential for corrosion, and visual evidence of corrosion with the bolting in place. If the evaluation'cannot confirm the integrity of the joint, the

o,e 28 ' licensee has proposed to remove one bolt nearest the leakage for VT-3 visual examination. ~ using the VT-1 acceptance criteria. The staff concludes that the acceptance criteria for VF-1 -{ examination are more appropriate and provide a comprehensive assessment of the structural j integrity of the bolting. As a result, significant pattems of degradation will be detected and i provides an acceptable level of quaiity and safety. Based on the licensee's proposed attemative, to evaluate the bolting at a leaking connection, the staff concluded that the degradation of bolting, if present, would be detected and provides an acceptable level of quality and safety. Therefore, the licensee's proposed altamative is authorized pursuant to 10 CFR 50.55a(s)(3)(i).

3. CONCLUSION The staff concluded that based on the review of the Duane Amold Energy Center, Third 10-Year Intervalinservice Inspection Program Plan, Revision 0, the licensee's responses to the Nuclear Regulatory Commission's requests for additional information, and the recommendations for granting relief from the ISI examinations that cannot be performed to the extent required by Section XI of the ASME Code, no deviations from regulatory requirements or commitments were identified.

Pursuant to 10 CFR 50.55a(g)(6)(i), the staff has determined that certa!n inservice examinations cannot be performed to the extent required by Section XI of the ASME Code. For Requests for Relief NDE-R006, NDE-R007, NDE-R008, NDE-R009, NDE-RO10, NDE-R021, and NDE-R023, the licensee has demonstrated that specific Section XI requirements are impractical; therefore, relief is granted and attemative imposed, as indicated, for the above requests for relief. The granting of these reliefs will not endanger life, property, or the common defense and security and is otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility. Specifically, th!s evaluation has not identified any practical method by which the licensee can meet ell the specific inservice inspection requirements of Section XI of the ASME Code for the existing Duane Arnold Energy Center. Compliance with all the exact Section XI required inspections would necessitate redesign of a significant number of plant systems, procurement of replacement components, installation of the new components, and baseline examinations of these components. Even after the redesign efforts, complete compliance with the Section XI examination reg irements probably could not be achieved. Therefore, it is concluded that the public interest is m? served by imposing certain provisions of Section XI of the ASME Code that have been determined to be impractical. - Pursuant to 10 CFR 50.55a(a)(3)(i), the proposed altematives in Requests for Relief NDE-RO11, NDE-RO12, NDE-RO13, NDE-RO14, NDE-RO15, NDE-RO17, NDE-RO18, PR-001, and PR-002 are authorized in that they provide an acceptabie level of quality and safety. For Request for Relief PR-003, PR-004, PR-005, PR-006, and PR-007, code compliance will result in hardship or unusual difficulty without a compensating increase in safety, in these cases, the licensee's proposed attematives are authorized pursuant to 10 CFR 50.55a(a)(3)(ii).

I s

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29 Request for Relief NDE-R020 is not in scope of this review and will be evaluated by the NRC in a separate report. For Request for Relief NDE-R004, it has been determined that relief is not required. 1 The licensee withdrew Requests for Relief NDE-R001, NDE-R002, NDE-R003, NDE-R005, NDE-R016, NDE-RO19, NDE-R022, NDE-R024, NDE-R025, and NDE-R026. l Principal Contributor T. McLellan Date: March 23, 1998 4 ) 4 .}}