ML20206G187

Safety Evaluation Approving Third 10-year ISI Program Requests for Relief (RR) RR-08,RR-15 & RR-17

ML20206G187
Person / Time
Site:	Brunswick
Issue date:	05/04/1999
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20206G185	List: ML20206G181 ML20206G187
References
NUDOCS 9905070112
Download: ML20206G187 (10)

Text

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'l ' - o NUCLEAR REGULATORY COMMISSION 5 j WASHINGTON, D. C. 20SF5

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE INSERVICE INSPECTION PROGRAM REQUEST FOR RELIEF BRUNSWICK STEAM ELECTRIC PLANT. UNIT NOS. UNITS 1 AND 2 DOCKET NUMBERS 50-324 AND 50425

1.0 INTRODUCTION

l' The Code of Federal Regulations,10 CFR 50.55a, requires that inservice inspection (ISI) of certain American Society of Mechanical Engineers (ASME) Code Class 1,2, and 3 components ba performed in accordance with Section XI of the ASME Boiler and Pressure Vessel (B&PV)

Colie applicable Edition and Addenda, except where specific written relief has been requested by the licensee and granted by the Commission pursuant to paragraph 10 CFR 50.55a (g)(6)(i),

or altamatives approved pursuant to 10 CFR 50.55a (a)(3). In proposed attematives, the licensee must demonstrate that: (1) the proposed alternatives provide an acceptable level of

. quality arid safety; or (2) compliance would result in hardship or unusual difficulty without a compensaiing increase in the level of quality and safety, in requesting relief, the licensee must demonstrate that the requirement is impractical for their facility. In accordance with Generic Letter (GL) 90 0g, Altemative Requirements for Snubber VisualInspection Intervals and Corrective Actions, Carolina Power and Light Company (CP&L) submitted a request for relief for snubbers (Relief Request RR-8, Revision 0) from ASME B&PV,Section XI, requirements for the Brunswick Steam Electric Plant Units Nos.1 and 2, third 10-year interval ISI Program Plan.

ASME Code,Section XI, Paragraphs IWB-2420(a) and IWC-2420(a) require the sequence of _ y component examinatic'1s established during the first inspection interval be repeated during each

- successive inspection interval, to the extent practical. Pursuant to 10 CFR 50.55a(a)(3)(i), the licensee submitted RR-15 to request relief from the Code-required sequence of component examinations as specified in lWB-2420(a) and IWC-2420(a). The third 10-year ISI Program is based on the 1989 Edition of the ASME B&PV Code,Section XI. The second 10-year ISI Program was based on the 1980 Edition of the Code. Due to differences in the requirements of IWA-5250 contained in these two Code editions, CP&L submitted Relief Request RR-17,

" Leakage at Bolted Connections."

10 CFR 50.55a allows the NRC staff to grant relief from ASME Code requirements upon making the necessary findings. The NRC staff's findings with respect to granting or not granting the requested reliefs as part of the licensee's ISI program are contained in this Safety Evaluation (SE).

304 Enclosure

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2.0 EVALUATION 2.1 Request for Relief No. RR-08

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The licensee requests relief from the examination and testing requirements of the ASME B&PV

' Code, Sect. ion XI, Article IWF-5000, for snubbers at Brunswick Steam Electric Plant (BSEP) 1 Units 1 and 2.-

2.1.1 Basis for Reauested Relief

. CP&L considers that 'mplementation of the alternative requirements outlined in BSEP's Technical Review Manual (TRM) will provide an acceptable level of quality and safety. The TRM consists of the identical snubber surveillance requirements as in the former BSEP's Technical Specifications (TS). TS 3/4.7.5 was previously amended to change the visual inspection requirements to be consistent with the guidance contained in GL 90-09. The use of.

the GL 90-09 attemative guidance alleviates expenditure of unnecessary resources, and reduces radiological exposure associated with snubber risual inspections.Section XI requires

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implementation of ASME/ ANSI OM-1987, Part 4. The implementejion of ASME/ ANSI OM-1987, j Part 4, for the third 10-year ISI would retum BSEP's snubber examination and testing program to the state which existed prior to the publication of GL 90-09, effectively canceling the benefits afforded by the GL. The licensee concluded that the TRM provides a level of quality and safety

. equal to or greater than the requirements of the ASME B&PV Code,Section XI, Article IWF-5000.

2.1.2 Altemate Method j The licensee proposes, as an alternative to the snubber examination and testing required by the ASME B&PV Code,Section XI, Article IWF-5000, to perform the BSEP snubber examinations

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and testing in accordance with requirements currently outlined in the TRM. Further, the attemative requirements will also be applied to preservice examination and testing of snubbers that are repaired or replaced. i 2.1.3 Eyaluation CP&L indicates, in its relief request, that the TRM is consistent with the guidance provided in the GL 90-09 attemative and implemented during the current (second 10-year interval) ISI snubber j examination and testing program.

The staff developed GL 90-09, in part, to reduce unnecessary radiological exposure associated l with snubber inspections. GL 90-09 provides an attemate schedule for snubber visual

Inspections that maintains the same confidence. level as the existing inspection intervals and

. allows for inspections and corrective actions during plant outages. The GL 90-09 altemative inspection interval is based on the number of unacceptable snubbers from the last inspection in proportion to the size of the various snubber populations or categories. The required Section XI interval for visual inspection is based only on the number of unacceptable snubbers found

- during the last inspection without regard to the snubber population. Licensees with a large )

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i population of snubbers find that the visual inspections are excessively restrictive, expend a significant amount of resources, and subject plant personnel to unnecessary exposure. The visual inspection provides for detection of impaired functional ability caused by physical damage, leakage, corrosion, or degradation from environmental exposure or operating conditions. The staff determined that the guidance provided in GL 90-09 for snubber visual inspection schedule is an acceptable alternative to the Section XI requirement, and has encouraged licensees to change their TS to be consistent with this guidance.

The snubber examination and test requirements of the TRM, which are identical to BSEP's former TS 3/4.7.5, provide an acceptable level of quality and safety and are acceptable as an alternative to the applicable requirements of the ASME B&PV Code,Section XI, Article IWF- ,

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1.4 CONCLUSION

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The staff concludes that the licensee's proposal to continue performirg snubber inservice 4 examination and testing during the third 10-year ISI in accordance with the TRM is acceptable. l The staff has determined that the proposed alternative to the ASME Code requirement, pursuant I

' to 10 CFR 50.55a (3)(a)(i), provides,an acceptable level of quality and safety.

2.2 Request for Relief No. RR-15 Paragraphs IWB-2420(a) and IWC-2420(a) require the sequence of component examinations established during the first inspection interval be repeated during each successive inspection interval, to the extent practical. The licensee requested relief from the Code-required sequence of component examinations as specified in IWB-2420(a) and IWC-2420(a).

2.2.1 Basis for Reauested Relief The licensee stated:

In accordance with 10 CFR 50.55a(a)(3)(i), Carolina Power and Light (CP&L) Company is requesting approval to use an alternative requirement to those specified in paragraph IWB-2420(a) and IWC-2420(a). CP&L proposes to sequence component examinations, established during the Second Inspection Interval, to the extent practica!.

CP&L has determined that sequencing of component examinations established during the Second Inspection Interval, to the extent practical, will provide an acceptable level of quality and safety for the following reasons:

1. During the First inspection Interval, BSEP was required to update the ISI Program to the latest Edition and Addenda of the ASME Code,Section XI incorporated by reference in 10 CFR 50.55a each inspection Period (i.e., every 40 months). Accordingly, BSEP implemented several Editions and Addenda of the ASME Code,Section XI (e.g.,1970 Edition,1974 Edition with Summer 1975 Addenda, and 1977 Edition with Summer 1978 Adderida). In several cases, the extent and/or frequency of examination specified in Table IWB-2500-1 and

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IWC-2500-1 listed in these Editions and Addenda have changed significantly in j the 1989 Edition of the'ASME Code,'Section XI. For example, the selection i criteria outlined in the'1977 Edition (with Summer 1978 Addenda) for ~

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- Examination Category C-F does not match the selection criteria outlined in the 1989 Edition for Examination Category C-F-1 or C-F-2. Thus, literal compliance with paragraphs IWB-2420(a) and IWC-2420(a) cannot be attained for the Third Inspection Interval.

2. During the First inspection Interval and the establishment of the Second Inspection Interval, minimum examination completion percentages were applied to the item Number (i.e., not the Category, as currently required). During this period of time, BSEP interpreted the requirements of IWB-2412(a) and

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IWC-2412(b) to apply to each Item Number. This approach required examiners 1 to enter radiation fields more than once to complete the required examinations.

Thus, following the same examination sequence established during previous intervals, without consideration for ALARA, does not provide a compensating increase in quality and safety. j

3. The requirement of IWB-2412(a) and IWC-2412(a) is to ensure initially selected components are reexamined during each inspection Interval, to the extent practical. The phrase "to the extent practical" allows the owner to take acceptable deviations from this requirement. CP&L considered re-sequencing components to reduce personnel exposure an acceptable deviation. During the Third inspection Interval, CP&L has re-selected the components examined during the Second Inspection Interval, as required, to comply with the applicable Examination Categories. CP&L is also maintaining the same examination

' sequence, as established during the Second Inspection interval; however CP&L has optimized their examination sequence to minimize personnel exposure as allowed by IWB-2412(a) and IWC-2412(a). To extent practical, CP&L has re-sequenced these examinations to minimize the time period between examination.

'2 2.2 Alternative Method

' The licensee stated:

During the Third Inspection interval, CP&L will sequence component examinations

established during the Second Inspection Interval, to the extent practical.

2.2.3 Evaluation Paragraphs IWB-2420(a) and IWC-2420(a) require continuation of the sequencing of examinations as established in the first inservice inspection interval. During the first inspection interval, CP&L was required to update their ISI Program to the latest Edition and Addenda of the

. ASME Code,Section XI incorporated by reference in 10 CFR 50.55a each inspection Period (i.e., every 40 months). This resulted in the implementation of several Editions and Addenda of the ASME Code,Section XI (e.g.,1970 Edition,1974 Edition with Summer 1975 Addenda, and n

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5-1977 Edition with Summer 1978 Addenda). The extent and frequency of examination specified in Tables IWB-2500-1 and IWC-2500-1 listed in these Editions and Addenda have changed significantly in the 1989 Edition of the ASME Code,Section XI. For example, the selection criteria outlined in the 1977 Edition (with Summer 1978 Addenda) for Examination Category C-F does not match the selection criteria outlined in the 1989 Edition for Examination Category C-F-1 or C-F-2. - Thus, the licensee cannot literally comply with the requirements of paragraphs IWB-2420(a) and IWC-2420(a) for their third Inspection interval.

During the first and second inspection intervals, CP&L applied minimum examination completion percentages to the item numbers as opposed to the category, as currently required. The '

licensee interpreted the requirements of IWB-2412(a) and IWC-2412(b) to apply to each item number. This required examiners to enter radiation fields more than once to complete the l

required examinations.

The licensee has proposed to sequence their subsequent component examinations as established during the second inspection interval to the extent practical. By so doing, the I licensee will be able to minimize personnel exposure, and maintain an examination cycle that is consistent with the intent of the Code requirement. The NRC staff believes that the licensee's proposed alternative to the Code requirements will provide an acceptable level of quality and safety. Therefore, it is recommended that the licensee's request to sequence their subsequent component examinations as established during the second inspection interval to the extent practical be authorized pursuant to 10 CFR 50.55a(a)(3)(i).

2.2.4. CONCLUSION The NRC staff evaluated the licensee's submittal and concluded that certain examinations cannot be performed to the extent required by the Code at BSEP, Units 1 and 2. For Request for Relief No. RR-15, the NRC Staff concludes that the licensee's proposed alternative will provide an acceptable level of quality and safety, and should be authorized pursuant to 10 CFR 50.55a(a)(3)(i) for the Third ISI interval.

2.3 Request for Relief No. RR-17 in accordance with AGME Code,Section XI, if leakage occurs at a bolted connection, Paragraph IWA-5250(a)(2) requires the removal of the bolting, a visual (VT-3) examination of the bolting for corrosion, and an evaluation in accordance with Paragraph IWA-3100. Pursuant to 10 CFR 50.55a(a)(3)(i), CP&L Company is requesting approval to use alternative requirements to those specified in paragraph IWA-5250(a)(2). If leakage is discovered at a bolted connection, the leakage will be located and evaluated for corrective measures. Where the evaluation of the variables determines the need for further evaluation, the bolt nearest the source of leakage will be removed and a VT-1 examination performed on the bolt.

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2.3.1 Basis for Reouested Relief The licensee stated:

Paragraph IWA-5250(a)(2) requires that if leakage occurs at a bolted connection, the bolting be removed, VT-3 visually examined for corrosion, and evaluated in accordance with IWA-3100. ASME Code Case N-566, " Corrective Action for Leakage Identified at Bolted Connections," which was approved by the ASME on August 9,1996, provides an alternative to the requirements of IWA-5250(a)(2) if one of the following requirements is met:

a) The leakage shall be stopped, and the bolting and component material shall be reviewed forjoint integrity.

b) If the leakage is not stopped, the joint shall be evaluated in accordance with IWB-3142.4 forjoint integrity. This evaluation shallinclude consideration of the number and condition of bolts, leaking medium, bolt and component material, system function, and leakage monitoring.

Code Case N-566 has not yet been incorporated into the latest revision of NRC Regulatory Guide 1.147, " Inservice inspection Code Case Acceptability--ASME Section XI, Division 1."

Revision 1 of ASME Code Case N-566 (i.e., N-566-1) retains the requirements regarding (1) stopping the leakage and evaluating the joint integrity, and (2) evaluating the joint integrity in accordance with IWB-3142.4 if the leakage is not stopped. Code Case N-566-1 clarifies that the following factors should be used in performing the evaluations:

1) The number and service age of bolts

2) Bolt and component material

3) Corrosiveness of process fluid leaking

4) Leakage location and system function

5) Leakage history at connection or other system components

6) Visual evidence of corrosion at connection (while connection is assembled)

As an alternative to the requirements of IWA-5250(a)(2), for BSEP, Unit 2 Refueling

- Outage 13 (i.e., B214R1) only, CP&L proposes to follow the requirements of ASME Code Case N-566-1.

Also, in addition to the requirements of Code Case N-566-1, CP&L proposes an additional action in those cases where the evaluation of the specified factors indicates the need for further evaluation. in such cases, a bolt closest to the source of leakage will be removed. The removed bolt will receive a VT-1 examination and be evaluated and dispositioned in accordance with IWB-3517. If the removed bolt shows evidence of rejectable degradation, all remaining bolts will be removed and receive a VT-1 examination in accordance with IWB-3140. If leakage is identified when the bolted

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connection is in service and the information in the evaluation is supportive, the removal . I of the bolt for the VT-1 examination may be deferred until the next refueling outage. l l

CP&L has determined that implementation of the proposed alternative will provide an acceptable level of quality and safety for the following reasons:

1. _CP&L has determined that implementation of the IWA-5250(a)(2) requirement can have an adverse impact on plant operation and personnel exposure. For example, the disassembly and re-assembly of components for the performance of the visual ,

(VT-3) examination on the bolting has the potential to delay the return of a safety related system to service, delay of plant startup following the completion of the Class 1 leakage test, and the potential for significant additional radiation dose.

2. A significant portion of the pressure retaining bolting is made of stainless steel materials. Since the normal Class 1 pressure boundary of a BWR contains only demineralized water, the likelihood of severe corrosion is minimal. While stainless steel bolting is more :usceptible to stress corrosion cracking under certain conditions, the detection of this type of corrosion on bolting material is difficult with the visual (VT-3) examination technique.

- 3. During each refueling outage, a Class 1 ASME Section XI leakage test is performed.

A majority of the bolted connection leakage found during these leakage tests is associated with the Control Rod Drive (CRD) housing connections. This is a common industry occurrence and, in most cases, the leakage stops within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of being pressurized to greater than 1000 psig. In addition, a number of CRDs are replaced each refueling outage. As with current practice, the bolting is replaced and a baseline visual (VT-3) examination performed prior to installation. Should leakage be detected at these CRDs, the requirements of IWA-5250(a)(2) would mandate removal of the bolting and performance of a VT-3 examination on the bolting that has just been examined, even though the bolting has not been exposed to the service environment. Thus, the removal of the bolting for the sole purpose of performing a visual (VT-3) examination would result in personnel exposure without a compensating increase in quality and safety.

4. The majority of the Class 2 systems transport a non-corrosive medium such as demineralized water, nitrogen, or air. Since the medium is non-corrosive, the bolted connections associated with these systems would not be susceptible to severe

. corrosion. Thus, the disassembly and re-assembly of a bolted connection for the performance of the visual (VT-3) examination of the bolting has the potential to delay the return of a safety related system to service.

Based on the above, the proposed alternative will ensure the structural integrity of the affected joint is maintained, while reducing operational, maintenance, and radiological hardships resulting from the current ASME Code requirement.

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i 2.3.2 Alternative Method The licensee stated:

During BSEP, Unit 2 Refueling Outage 13 (i.e., B214R1), when leakage is detected at bolted connections, as an alternative to the requirements of IWA-5250(a)(2), the ,

requirements of either 1 or 2 below shall be met:

1. The leakage shall be stopped and the bolting and component material shall be l evaluated to determine joint integrity and the susceptibility of the bolting to I corrosion and failure. The evaluation will, at a minimum, consider the following l factors-  !

l a) The number and service age of the bolts b) Bolt and component material l I

c) Corrosiveness of the process fluid that is leaking d) Leakage location and system function j e) Leakage history at the connection or other system components f) Visual evidence of corrosion at the connection (i.e., while the connection is assembled)

'2. If the leakage is not stopped, the joint shall be evaluated in accordance with IWB-3142.4 to determine joint integrity and the susceptibility of the bolting to corrosion and failure. The evaluation will, at a minimum, consider the following factors:

a) The number and service age of the bolts b) Bolt and component material c) Corrosiveness of the process fluid that is leaking d) Leakage location and system function e) Leakage history at the connection or other system components f) Visual evidence of corrosion at the connection (i.e., while the connection is assembled)

When the evaluation of the above factors is concluded, and if the evaluation determines that the leaking condition has not degraded the fasteners, then no further action is required. However, reasonable attempts shall be made to stop the leakage as appropriate. In accordance with IWB-3144(b), the evaluation analyses will be submitted to the regulatory authority having jurisdiction at the plant site.

3-e' if the evaluation of the factors in 1 or 2 above indicates the need for further evaluation, then a bolt closest to the source of leakage shall be removed. The bolt will receive a VT-1 examination and be evaluated and dispositioned in accordance with IWB-3517. If the removed bolting shows avidence of rejectable degradation, all remaining bolts shall be removed and receive a W-1 examination in accordance with IWB-3140. If leakage is identified when the bolted connection is in service and the information in the evaluation is supportive, the removal of the bolt for the VT-1 examination may be deferred until the next refueling outage.

2.3.3 Evaluation.

In accordance with IWA-5250(a)(2), if leakage occurs at a bolted connection, the bolting must be removed, VT-3 visually examined for corrosion, and evaluated in accordance with IWA-3100. In lieu of this requirement, the licensee has proposed to evaluate the bolting to determine its susceptibility to corrosion. The proposed evaluation will consider, as a minimum, bolting materials, the corrosive nature of the process fluid, the leakage location and history, the service age of the bolting materials, visual evidence of corrosion at the assembled connection and plant / industry studies of similar bolting materials in similar environments. The licensee has also proposed to perform a VT-1 visual exam in lieu of a VT-3 visual examination on the removed bolt. The VT-1 examination provides a more detailed examination versus a VT-3 visual examination. A VT-1 examination also has a defined acceptance criteria versus a W-3 visual examination. A VT-1 examination exceeds the examination attributes of a VT-3 examination, and provides greater quality and safety.

Based on the items included in the evaluation process, the staff determined that the evaluation proposed by the licensee presents a sound engineering approach and provides an acceptable level of quality and safety, in addition, if the initial evaluation indicates the need for a more detailed analysis, the bolt nearest to the source of leakage will be removed, VT-1 visually examined, and evaluated in accordance with IWB-3517. Therefore, the licensee's proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i) for the remainder of the second 10-year ISI interval.

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3.4 CONCLUSION

The staff has reviewed the licensee's submittal and concludes that the licensee's proposed alternatives provide an acceptable level of quality and safety. Pursuant to 10 CFR 50.55a(a)(3)(i), both relief requests are authorized for the third 10-year ISI interval. Therefore, the licensee's proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i).

Principal Contributors: F. Grubelich T. McLellan

, ' Date: May 4, 1999

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9 Mr. J. S. Keenan Brunswick Steam Electric Plant Carolina Power & Light Company Units 1 and 2 cc:

Mr. William D. Johnson Ms. Karen E. Long Vice President and Corporate Secretary Assistant Attomey General Carolina Power & Light Company State of North Carolina Post Office Box 1551 Post Office Box 629 Raleigh, North Carolina 27602 Raleigh, North Carolina 27602 Mr. Jerry W. Jones, Chairman Mr. Robert P. Gruber Brunswick County Board of Commissioners Executive Director Post Office Box 249 Public Staff - NCUC Bolivia, North Carolina 28422 Post Office Box 29520 Raleigh, North Carolina 27626-0520 Resident inspector U.S. Nuclear Regulatory Commission 8470 River Road Director Southport, North Carolina 28461 Site Operations Brunswick Steam Electric Plant Mr. John H. O'Neill, Jr. Post Office Box 10429 Shaw, Pittman, Potts & Trowbridge Southport, North Carolina 28461 2300 N Street, NW.

Washington, DC 20037-1128 Mr. William H. Crowe, Mayor City of Southport Mr. Mel Fry, Director 201 East Moore Street Division of Radiation Protection Southport, North Carolina 28461 N.C. Department of Environment and Natural Resources Mr. Dan E. Summers 3825 Barrett Dr. Emergency Management Coordinator Raleigh, North Carolina 27609-7721 New Hanover County Department of Emergency Management Mr. J. J. Lyash Post Office Box 1525 Plant Manager Wilmington, North Carolina 28402 Carolina Power & Light Company Brunswick Steam Electric Plant Mr. Terry C. Morton Post Office Box 10429 Manager Southport, North Carolina 28461 Performance Evaluation and Regulatory Affairs CPB 9 Public Service Commission Carolina Power & Light Company State of South Carolina Post Office Box 1551 Post Office Drawer 11649 Raleigh, North Carolina 27602-1551 Columbia, South Carolina 29211 Mr. K. R. Jury Manager- Regulatory Affairs Carolina Power & Light Company Post Office Box 10429 Southport, NC 28461-0429