ML18153A609
| ML18153A609 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 04/16/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML18153A608 | List: |
| References | |
| NUDOCS 9604240081 | |
| Download: ML18153A609 (8) | |
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Enclosure UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555--0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE THIRD TEN YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN REQUEST FOR RELIEF TO USE CODE CASES FOR
1.0 INTRODUCTION
VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION, UNITS 1 AND 2 DOCKET NUMBERS: 50-280 AND 50-281 The Technical Specifications for Surry Power Station, Units 1 and 2 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 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 alternatives 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 difficulties without a compensating increase in the level of quality and safety.
Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class l, 2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the 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 ten-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 applicable edition of Section XI of the ASME Code for the Surry Power Station, Units 1 and 2 third 10-year inservice inspection (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.
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 support 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 960424-0081 960416 PDR ADOCK 05000280 G
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2 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.
In a letter dated December 7, 1995, Virginia Electric and Power Company, submitted to the NRC Requests for Relief to use Code Case N-522 and N-535 at the Surry Power Station, Units 1 and 2.
2.0 EVALUATION AND CONCLUSIONS The staff, with technical assistance from its contractor, the Idaho National Engineering Laboratory (INEL}, has evaluated the information provided by the licensee in support of its third Ten-Year Interval Inservice Inspection Program Plan, Requests for Relief to use Code Case N-522 and N-535 at the Surry Power Station, Units 1 and 2.
Based on the information submitted, the staff adopts the contractrir's conclusions and recommendations presented in the Technical Letter Report attached.
The ~taff has concluded that the proposed alternatives contained in Requests for Relief to use Code Cases N-522 and N-535 at the Surry Power Station provide an acceptable level of quality and safety.
For Code Case N-522, staff concludes 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 calculated peak 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 subject to either a Type B or C test, its safety function is verified and Code Case N-522 may be used.
For Class 2 pipe segments between the CIVs that are not subject to either a Type B or C test, the safety function is not verified and Code Case N-522 may not be used.
Therefore, the Requests for Relief to use Code Cases N-522 and N-535 at the Surry Power Station is authorized pursuant to 10CFRS0.55a(a)(3)(i).
Principal Contributor:
T. Mclellan Date: April 16, 1996
ATTACHMENT TECHNICAL LETTER REPORT e
THIRD TEN-YEAR INTERVAL ISI REQUESTS FOR RELIEF TO USE CODE CASES VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 DOCKET NUMBERS 50-280 AND 50-281
1.0 INTRODUCTION
In a letter dated December 7, 1995, the licensee, Virginia Electric and Power Company, submitted requests for relief for use of Section XI Code Cases N-522 and N-535.
These requests are for the third ten-year inservice inspection (ISI) interval at the Surry Power Station, Units 1 and 2.
The Idaho National Engineering Laboratory (INEL) staff has evaluated the subject requests in the following section.
2.0 EVALUATION The Code of record for the Surry Power Station, Units 1 and 2, third ten-year ISi interval is the American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, 1989 Edition.
The information provided by the licensee in support of the requests has been evaluated and the bases for disposition are documented below.
A.
Request for Authorization to Use ASME Code Case N-522 Code Requirement: Section XI, Table IWC-2500-1, Examination Category C-H requires pressure tests and associated VT-2 visual examinations.
Code cases are periodically published by ASHE to either clarify the intent of the Code rules or to provide alternatives to existing Code requirements.
Use of these nonmandatory Code cases for ISI is subject to general acceptance by the NRC staff and 1
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incorporation into Regulatory Guide 1.147. Pursuant to 10 CFR 50.SSa, other Code cases may be used provided specific NRC authorization is obtained.
Licensee's Code Relief Request:
Relief is requested from performing the Code-required pressure tests and associated VT-2 visual examinations for the portions of the subject piping penetrating containment, classified as Code Class 2.
The attaching segments of piping inside and outside of containment are nonclass.
Licensee's Basis for Requesting Relief (as stated):
"Code Case N-522 permits the use of Appendix J leakage testing requirements as an alternative to the rules in the Code that govern the pressure testing of certain containment penetrations.
Application of this Code Case will reduce the pressure testing requirements for these containment penetrations consistent with the Appendix J performance-based testing requirements for containment penetrations."
Licensee's Proposed Alternative Examination:
Virginia Electric and Power Company proposes to apply Code Case N-522.
This permits 10 CFR 50, Appendix J testing of Class 2 piping and isolation valves that are part of the containment system to be substituted for the Code required testing.
Application of this Case is restricted to systems where the balance of the piping system is outside the scope of Section XI.
Evaluation:
The Code-required Table IWC-2500-1, Category C-H system pressure leakage tests and VT-2 visual examinations provide verification of the l~ak-tight integrity of the Class 2 piping systems or segments once every 40 months at the Surry Power Station, Units 1 and 2.
The piping segments from non-code class systems that penetrate containment are designed and examined as Class 2 pipe in order to protect the integrity of the containment.
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e Appendix J pressure testing provides periodic verifica~ion of the leak-tight integrity of the primary reactor containment and systems and components that penetrate containment.
The frequency of Appendix J testing provides assurance that the containment pressure boundary is being maintained at an acceptable level while monitoring for deterioration of seals, valves, and piping.
Appendix J also requires that Type Band C tests be performed each refueling outage, but in no case at intervals greater than two years.
The Class 2 containment isolation valves (CIVs) and connecting pipe segments must withstand the peak calculated containment internal pressure associated with the maximum design containment pressure. The containment penetration piping is classified as Class 2 because of its function as part of the containment pressure boundary, and because containment integrity is the only safety-related function performed by this penetration piping.
Therefore, it is logical to test the penetration piping portions of the associated systems to the Appendix J criteria. The INEL staff concludes 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 calculated peak 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 and Code Case N-522 may be used.
For Class 2 pipe segments between the CIVs that are not subjected to either a Type B or C test, the safety function is not verified and Code Case N-522 may not be used.
Section XI, IWC-52IO(b) requires that where air or gas is used as a testing medium, the test procedure shall include methods for detection and location of through-wall leakage in components of 3
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e the system tested. Because an Appendix J, Type C test most likely uses air as a testing medium, Virginia Electric and Power Company's test procedure should meet the above requirement for the CIVs and pipe segments between the CIVs.
The INEL staff believes that an acceptable level of quality and safety will be provided by Appendix J tests, provided that the licensee performs the leak test at the peak calculated containment design pressure and that a test procedure is implemented that provides for detection and location of through-wall leakage in the piping segments and valves that are being tested. Therefore, it is reconvnended that the licensee's proposed alternative pressure test be authorized pursuant to 10 CFR 50.55a(a)(3)(i), subject to the conditions given above.
Request for Authorization to Use ASME Code Case N-535 Code Requirement:
Paragraph IWA-2432 requires that successive inspection intervals be comprised of 10 years following the previous interval except as modified by Paragraph IWA-2430(d).
Paragraph IWA-2430(d) allows an interval to be extended or reduced by as much as one year to coincide with an outage, thus changing the length of an interval.
Code cases are periodically published by ASME to either clarify the intent of the Code rules or to provide alternatives to existing Code requirements.
Use of these nonmandatory Code cases for ISI is subject to general acceptance by the NRC staff and incorporation into Regulatory Guide 1.147.
Pursuant to 10 CFR 50.SSa, other Code cases may be used provided specific NRC authorization is obtained.
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Licensees' Code Relief Request:
The licensee requested authorization to use Code Case N-535, Alternative Requirements for Inservice Inspection Intervals,Section XI, Division 1.
Licensee's Basis for Requesting Relief (as stated):
MCode Case N-535 interprets inspection scheduling requirements and allows both interval and period extensions of up to one year to enable an inspection to coincide with a plant outage. Application of this Code Case would provide additional inspection scheduling flexibility in completing period-specific inspections allowing better application of inspection resources during refueling outages."
Licensee's Proposed Alternative Examination:
Virginia Electric and Power Company proposes to apply Code Case N-535, Alternative Requirements for Inservice Inspection Intervals,Section XI, Division 1.
Evaluation:
Paragraph IWA-2432 requires that successive inspection intervals be comprised of 10 years following the previous interval except as modified by Paragraph IWA-2430(d).
Paragraph IWA-2430(d) allows an interval to be extended or reduced by as much as one year to coincide with an outage, thus changing the length of an interval. The licensee proposes to apply the requirements of Code Case N-535 for the scheduling of intervals and examinations of Code Class 1, 2, and 3 piping and components.
This is in lieu of the existing Code requirements of Paragraph IWA-2432 as modified by Paragraph 2420(d).
Code Case N-535 is broken into four parts; these a) allow a one-year extension of an inspection interval. Also, a successive interval may start prior to the end of the previous interval that was extended; b) prohibit examinations performed as part of the extended interval from being credited in the successive interval; 5
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e c) allow an inspection period to be extended or reduced to coincide with an outage; and d) require examination records to identify in what interval the examination was performed.
Part (a) of the case is the only change from current Section XI requirements.
The one-year extension is independent-of the plant operating cycle and two intervals can be open concurrently during that year. Although slightly different from current Code requirements, this case does not change the number of examinations, acceptance criteria, or any other Code requirement.
Therefore, the INEL staff believes that Case N-535 provides an acceptable level of quality and safety.
The licensee's proposed alternative, to implement Case N-535 for the scheduling of intervals and examination of Class 1, 2, and 3 piping and components, will provide an acceptable level of quality and safety because, as explained above, it only clarifies and adds flexibilty to examination scheduling and does not change any other Code requirement. Therefore, it is recommended that the proposed alternative be authorized, pursuant to 10 CFR 50.55a(a)(3)(i).
3.0 CONCLUSION
The INEL staff has reviewed the alternatives proposed by the licensee for the use of Code Cases N-522 and N-535 and concludes that the alternatives will provide an acceptable level of quality and safety. For Case N-522, it is reconvnended that the proposed alternative be authorized pursuant to 10 CFR 50.55a(a)(3)(1), with the conditions stated in the evaluation. For Case N-535, it is reco11111ended that the proposed alternative be authorized pursuant to 10 CFR 50.55a(a)(3)(i).
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