ML18318A275

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Alternative Relief Requests Use of Boiling Water Reactor Vessel and Internals Project Guidelines in Lieu of Specific ASME Code Requirements
ML18318A275
Person / Time
Site: Nine Mile Point  Constellation icon.png
Issue date: 12/13/2018
From: James Danna
Plant Licensing Branch 1
To: Bryan Hanson
Exelon Nuclear
Marhsall M, NRR/DORL/LPL, 415-2871
References
EPID L-2018-LLR-0085
Download: ML18318A275 (10)
v • d • e


Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 13, 2018 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

NINE MILE POINT NUCLEAR STATION, UNITS 1 AND 2 - ISSUANCE OF RELIEF REQUESTS RE: USE OF BOILING WATER REACTOR VESSEL AND INTERNALS PROJECT GUIDELINES IN LIEU OF SPECIFIC ASME CODE REQUIREMENTS (EPID L-2018-LLR-0085)

Dear Mr. Hanson:

By letter dated June 8, 2018 (Agencywide Documents Access and Management System Accession No. ML18159A059), Exelon Generation Company, LLC (the licensee) submitted Relief Requests 15R-03 and 14R-03 for the Nine Mile Point Nuclear Station, Units 1 and 2 (Nine Mile Point 1 and 2), respectfully, to (among other things) apply alternative examination methods to certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), Section XI, inservice inspection (ISi) requirements for Class 1 components. These requests were submitted for the fifth and fourth 10-year ISi intervals.

Specifically, the licensee proposed to use the Boiling Water Reactor Vessel and Internals Project (BWRVIP) inspection and evaluation guidelines as an alternative to the requirements of Section XI of the ASME Code for ISi of the reactor pressure vessel interiors, interior attachments within the beltline region, and core support structures at Nine Mile Point 1 and 2.

Pursuant to Title 1O of the Code of Federal Regulations ( 10 CFR) Section 50.55a(z)( 1), the licensee requested to use the proposed alternative on the basis that it provides an acceptable level of quality and safety.

The U.S. Nuclear Regulatory Commission staff has reviewed the subject requests and concludes, as set forth in the enclosed safety evaluation, that the alternative proposed by the licensee will ensure the integrity of the subject components, and that the alternative provides an acceptable level of quality and safety, and has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(z)(1 ). Therefore, pursuant to 10 CFR 50.55a(z)(1 ), the licensee's proposed alternative is authorized for the fifth and fourth 10-year ISi intervals at Nine Mile Point 1 and 2, respectively, with the condition that in the event the licensee wishes to take exceptions to, or deviations from, the NRC staff-approved BWRVIP inspection and evaluation guidelines authorized in this alternative, the licensee must revise and resubmit its request for authorization to use the proposed alternative under 10 CFR 50.55a.

The NRC staff will provide separate correspondence regarding review of the other relief requests submitted in the licensee's June 8, 2018, letter (15R-04, 15R-05, and 15R-06 for Unit 1, and 14R-04, 14R-05, and 14R-06 for Unit 2).

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

If you have any questions, please contact Jennifer Tobin at 301-415-2328 or Jennifer.Tobin@nrc.gov.

Sincerely, S::2?~

Plant Licensing Branch 1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-220 and 50-410

Enclosure:

Safety Evaluation cc: Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO RELIEF REQUESTS 15R-03 (UNIT 1) AND 14R-03 (UNIT 2)

EXELON GENERATION COMPANY, LLC NINE MILE POINT NUCLEAR STATION, UNITS 1 AND 2 DOCKET NOS. 50-220 AND 50-410

1.0 INTRODUCTION

By letter dated June 8, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18159A059}, Exelon Generation Company, LLC (the licensee) submitted Relief Requests 15R-03 and 14R-03 for the inservice inspection (ISi) program at Nine Mile Point Nuclear Station, Units 1 and 2 (Nine Mile Point 1 and 2). These requests were submitted for the fifth and fourth 10-year ISi intervals at Nine Mile Point 1 and 2, respectively, and are applicable to the reactor vessel internal (RVI) components. In this safety evaluation, the term "RVI components" includes reactor pressure vessel (RPV) interiors, interior attachments within the beltline region, and core support structures. The licensee proposed to use the Boiling Water Reactor (BWR) Vessel and Internals Project (BWRVIP) guidelines as an alternative to the requirements of Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code} for the ISi of the RPV interior surfaces, attachments, and core support structures.

2.0 REGULATORY EVALUATION

The ISi of ASME Code Class 1, 2, and 3 components is to be performed in accordance with Section XI of the ASME Code, and applicable edition and addenda, as required by Title 10 of the Code of Federal Regulations (10 CFR) Section 50.55a(g). Pursuant to 10 CFR 50.55a(z),

alternatives to the requirements of paragraph (g) may be used when authorized by the NRC if: (1) the proposed alternatives would provide an acceptable level of quality and safety; or (2) compliance with the specified requirement 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) must meet the requirements, except the design and access provisions and the pre-service examination requirements, set forth in the ASME Code, Section XI, to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system Enclosure

pressure tests conducted during the first 10-year ISi 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(a}(1 )(ii), 12 months prior to the start of the 120-month interval, subject to the conditions listed in 10 CFR 50.55a(b )(2).

Nine Mile Point 1 is currently in the fourth 10-year ISi interval. The fifth interval will begin on August 23, 2019, and is scheduled to end on August 22, 2029. Nine Mile Point 2 is currently in the fourth 10-year ISi interval, which began on August 23, 2018, and is scheduled to end on August 22, 2028.

3.0 TECHNICAL EVALUATION

3.1 Background The licensee proposed an alternative to the requirements of the ASME Code, Section XI, for the Class 1 RVI components at Nine Mile Point 1 and 2 under 10 CFR 50.55a(z)( 1).

3.2 ASME Code Requirements The ASME Code, Section XI requires visual examination (VT) of the RVI components. The specific examination requirements, as specified in Table IWB-2500-1 of the ASME Code, Section XI, Examination Categories B-N-1 and B-N-2, are identified below:

  • B 13.10 - Examine accessible areas of the RPV interior surfaces each inspection period using a technique that meets the requirements for a VT-3 examination as defined in paragraph IWA-2213 of the ASME Code, Section XI (Category B-N-1 ).
  • B13.20 - Examine RPV interior attachment welds within the beltline region each inspection interval using a technique that meets the requirements for a VT-1 examination as defined in paragraph IWA-2211 of the ASME Code, Section XI (Category B-N-2).
  • B13.30 - Examine RPV interior attachment welds beyond the beltline region each inspection interval using a technique that meets the requirements for a VT-3 examination, as defined in paragraph IWA-2213 of the ASME Code, Section XI (Category B-N-2).
  • B13.40 - Examine surfaces of the core support structure each inspection interval using a technique that meets the requirements for a VT-3 examination, as defined in paragraph IWA-2213 of the ASME Code, Section XI (Category B-N-2).

These examinations are performed to assess the structural integrity of the RVI components.

3.3 Applicable ASME Code Edition and Addenda For the fifth and fourth 10-year ISi intervals at Nine Mile Point 1, the Code of record for the inspection of ASME Code Class 1, 2, and 3 components is the 2013 Edition of the ASME Code, Section XI.

3.4 Licensee's Proposed Alternative to the ASME Code The licensee proposed to use the BWRVIP inspection and evaluation (l&E) guidelines as an alternative to the examination requirements of the ASME Code, Section XI, for ISi of Category B-N-1 and B-N-2 RVI components. The licensee stated that implementation of this alternative inspection program will maintain an adequate level of quality and safety for the affected components and will not adversely impact the health and safety of the public. As part of its justification for requesting the alternative, the licensee stated that BWRs now examine these RVI components in accordance with the BWRVIP l&E guidelines. The licensee stated that the proposed alternative covers exa.mination methods, examination volume, frequency, training, successive and additional examinations, flaw evaluations, and reporting criteria. The licensee indicated that the BWRVIP l&E guidelines have been written to address the examination of safety-significant RVI components using appropriate methods and re-inspections at conservative intervals.

3.5 Licensee's Basis for Use of Alternative The licensee's submittal for Requests ISR-03 and 14R-03 cited the BWRVIP reports listed below as the basis for its alternative inspection of the subject RVI components. The BWRVIP reports listed below include BWRVIP l&E guidelines that are applicable to the Category B-N-1 and B-N-2 RVI components, as well as BWRVIP l&E guidelines for additional RVI components that are not traditionally within the scope of Category B-N-1 and B-N-2 components.

  • BWRVIP-06, Revision 1-A, "BWR Vessel and Internals Project, Safety Assessment of BWR Reactor Internals"
  • BWRVIP-25, "BWR Core Plate Inspection and Flaw Evaluation Guidelines"
  • BWRVIP-26-A, "BWR Top Guide Inspection and Flaw Evaluation Guidelines"
  • BWRVIP-38, "BWR Shroud Support Inspection and Flaw Evaluation Guidelines"
  • BWRVIP-41, Revision 4, "BWR Jet Pump Assembly Inspection and Flaw Evaluation Guidelines"
  • BWRVIP-47-A, "BWR Lower Plenum Inspection and Flaw Evaluation Guidelines"
  • BWRVIP-48-A, "Vessel ID [Internal Diameter] Attachment Weld Inspection and Flaw Evaluation Guidelines"
  • BWRVIP-76, Revision 1-A, "BWR Core Shroud Inspection and Flaw Evaluation Guidelines"
  • BWRVIP-94NP, Revision 2, "BWR Vessel and Internals Project Program Implementation Guide"
  • BWRVIP-138, Revision 1-A, "Updated Jet Pump Beam Inspection and Flaw Evaluation"
  • BWRVIP-180, "BWR Vessel and Internals Project, Access Hole Cover Inspection and Flaw Evaluation Guidelines"
  • BWRVIP-183-A, "Top Guide Grid Beam Inspection and Flaw Evaluation Guidelines" The licensee stated that inspection services by an Authorized Inspection Agency will be applied to the proposed alternative. The licensee further indicated that the BWRVIP has established a

reporting protocol for examination results and deviations. The licensee stated that any revised version of a BWRVIP report used to satisfy this alternative will meet or exceed the l&E guidelines of its original version, and if it does not meet this criteria, NRC staff approval is mandatory prior to its implementation, consistent with the requirements of BWRVIP-94.

The licensee stated that by implementing the BWRVIP inspection guidelines, aging degradation of the RVI can be identified in a timely manner so that proper corrective action can be taken to ensure the integrity of the affected RVI component. Therefore, the licensee concluded that implementation of the .BWRVIP inspection guidelines for the Nine Mile Point 1 and 2 RVI components will provide an acceptable level of quality and safety. These results are documented in letters submitted by the Electric Power Research Institute, "Project No. 704 -

BWR Vessel and Internals Inspection Summaries for Spring 2017 Outages," dated February 7, 2018 (ADAMS Accession No. ML18040A464), and "Project No. 704 - BWR Vessel and Internals Inspection Summaries for Spring 2016 Outages," dated November 28, 2016 (ADAMS Accession No. ML17304A944), for Nine Mile Point 1 and 2, respectively. The inspection summaries address RVI inspections through the spring 2017 refueling outage for Nine Mile Point 1 and the spring 2016 refueling outage for Nine Mile Point 2.

3.6 Duration of Proposed Alternative The licensee submitted this request for the fifth and fourth ISi intervals for Nine Mile Point 1 and 2, respectively. The fifth ISi interval at Nine Mile Point 1 will begin on August 23, 2019, and is currently scheduled to end August 22, 2029. The fourth ISi interval at Nine Mile Point 2 began on August 23, 2018, and is currently scheduled to end August 22, 2028.

4.0 NRC STAFF EVALUATION The NRC staff reviewed the information provided by the licensee in its submittal regarding its proposed alternative to the ASME Code, Section XI, Category B-N-1 and B-N-2 examination requirements for the RPV interior surfaces, attachments, and core support structure, and the technical basis for the licensee's proposed alternative. The staff reviewed the status of each of the referenced BWRVIP guidance documents and noted that the BWRVIP did not submit the BWRVIP-180 inspection guidelines for the access hole covers to the NRC staff for review and approval. However, even though the staff did not review BWRVIP-180, the licensee may choose to implement the enhancements described in BWRVIP-180. These enhancements (if chosen) may be implemented because they bound the inspection requirements of the ASME Code, Section XI, for the Category B-N-1 and B-N-2 components. In addition, BWRVIP-183 addresses the l&E guidelines for the top guide, which is currently under review by the staff.

However, the licensee may choose to implement l&E guidelines that are consistent with the staff-approved BWRVIP-26-A report for the top guide components in lieu of BWRVIP-183. The staff found the remaining referenced BWRVIP reports to be acceptable for use, provided that any conditions associated with each BWRVIP report are followed. The conditions are contained in the corresponding staff safety evaluation for each report.

The NRC staff reviewed the BWRVIP reports referenced in the licensee's submittal to determine if they are acceptable for use in lieu of the ASME Code, Section XI, Examination Category B-N-1 and B-N-2 requirements. Based on its review, the NRC staff found the referenced BWRVIP reports identified in the licensee's submittal to be acceptable for use because the l&E guidelines addressed in these reports would identify degradation in a timely manner and ensure that the integrity of the subject components will be maintained. In addition, Nine Mile Point compliance with the l&E guidelines would provide reasonable assurance that age-related degradation in the

subject components will be identified in a timely manner. The details of the NRC staff's assessment of these BWRVIP reports for the purposes of the licensee's proposed alternative is documented below.

Specifically, BWRVIP-06 (Revision 1-A), BWRVIP-18 (Revision 2-A), BWRVIP-26-A, BWRVIP-42 (Revision 1-A), BWRVIP-47-A, BWRVIP-48-A, BWRVIP-76 (Revision 1-A),

BWRVIP-138 (Revision 1-A), and BWRVIP-183-A, have been previously reviewed and approved by the NRC staff with a corresponding safety evaluation attached to each of the "-A" reports. Although BWRVIP-25 and BWRVIP-38 do not have a corresponding "-A" report, they were reviewed and approved by the NRC staff by letters dated December 19, 1999, and July 24, 2000, respectively. During the NRC staff's review of these reports, as documented in the respective "-A" report, it was determined that degradation can be identified in a timely manner and ensures that the integrity of the subject components will be maintained. Thus, the staff aut~orizes the use of these BWRVIP l&E guidelines in lieu of ASME Code requirements because the inspection techniques recommended by the BWRVIP meet or exceed the inspection techniques mandated by the ASME Code, Section XI, ISi program, and the inspection frequencies are sufficient to detect aging degradation.

The BWRVIP-41, Revision 4, l&E guideline was approved by the NRC staff in its safety evaluation dated July 2, 2018 (ADAMS Accession No. ML18130A024), which also identifies conditions associated with its use. The NRC staff determined that the report incorporates adequate l&E guidelines to detect degradation in the subject components in a timely manner and ensures that the integrity of the subject components will be maintained. Thus, the staff authorizes the use of the l&E guidelines in BWRVIP-41, Revision 4, in lieu of ASME Code requirements for the subject components because the inspection techniques recommended by the BWRVIP meet or exceed those mandated by Section XI of the ASME Code, and the inspection frequencies are sufficient to detect aging degradation.

The BWRVIP-180 l&E guideline has not been submitted to the NRC for review and approval.

However, based on the NRC staff's review of the report for the purpose of the licensee's proposed alternative, it was noted that the l&E guideline meets or exceeds the inspection frequency and techniques mandated by Section XI of the ASME Code, and degradation can be identified in a timely manner, which ensures the integrity of the subject components will be maintained. Thus, the staff authorizes the use of BWRVIP-180 in lieu of ASME Code requirements for the subject components.

In addition, the staff notes that BWRVIP-03 and BWRVIP-94NP, Revision 2, do not contain l&E guidelines for any specific components. Rather, BWRVIP-03, in general: (1) provides an overview of the structure of the BWRVIP; and (2) includes guideline documents that establish protocols to follow in order to gain access to BWRVIP-owned mockups, to perform formal demonstrations of nondestructive examination techniques using BWRVIP mockups, and to perform their own demonstrations of nondestructive examination techniques or inspection tooling in an acceptable manner. Furthermore, BWRVIP-94NP, Revision 2, establishes a framework for structuring and strengthening existing BWR vessel and internals programs to ensure consistent application of guidelines by BWRVIP members. The staff notes that these two documents are integral to the implementation of the BWRVIP and the associated l&E guidelines, including those associated with the licensee's submittal.

As part of its evaluation of this proposed alternative, the NRC staff reviewed the results of the licensee's BWRVIP inspection history up until the most recent inspections in 2017 and 2016, for Nine Mile Point 1 and 2, respectively. These results were referenced in the licensee's submittal

as supporting information and provide information regarding inspection methods used on the subject components, inspection dates, the inspection results, and corrective actions related to the inspection findings. These results are documented in letters submitted by the EPRI "Project No. 704 - BWR Vessel and Internals Inspection Summaries for Spring 2017 Outages," and "Project No. 704 - BWR Vessel and Internals Inspection Summaries for Spring 2016 Outages,"

for Nine Mile Point 1 and 2, respectively. Based on its review of these inspection summaries for Nine Mile Point, the NRC staff finds that the licensee has adequately demonstrated its capability in: (1) identifying the weld flaws (cracking), as well as other relevant indications; (2) taking appropriate corrective actions to ensure that the structural integrity of the component is maintained (i.e., proper repair, if necessary, or flaw evaluation with proper engineering justification); and (3) complying with scope expansion of inspections and subsequent inspections per the applicable BWRVIP reports.

NRC Summary In summary, the NRC staff finds that the BWRVIP l&E guidelines require more frequent and more comprehensive inspections of the RVI components for aging effects than those required by the ASME Code, Section XI, Categories B-N-1 and B-N-2. Therefore, subsequent inspections of the RVI components per the applicable BWRVIP l&E guidelines will provide reasonable assurance that any emerging aging effects will be identified in a timely manner. In addition, the more frequent inspections of the RVI components in accordance with these BWRVIP guidelines will enable the licensee to effectively monitor the existing aging degradation in the RVI components. Consistent with the determination that was made in the staff's safety evaluations that approved each of the cited BWRVIP inspection requirements, the licensee's proposed alternative will, therefore, comprehensively identify and evaluate aging degradation of the RVI components at Nine Mile Point 1 and 2. Accordingly, the staff finds that the implementation of the inspection requirements specified in the licensee's proposed alternative will ensure that the integrity of the RVI components at Nine Mile Point 1 and 2 will be maintained with an acceptable level of quality and safety.

If the licensee wishes to take exceptions to, or deviations from, the NRC staff-approved BWRVIP inspection guidelines authorized in this ASME Code alternative, the licensee must revise and resubmit its request for authorization to use the proposed alternative under 10 CFR 50.55a.

The NRC staff acknowledges that the BWRVIP Executive Committee periodically revises the BWRVIP guidelines to include enhancements to inspection techniques and flaw evaluation methodologies. While the licensee may choose to implement enhancements described in a revised version of a BWRVIP inspection guideline, the licensee must also continue to meet the requirements of the version of the BWRVIP inspection guideline that forms the safety basis for the staff-authorized alternative to the requirements of the ASME Code, Section XI, under 10 CFR 50.55a(z). The licensee may, of course, also choose to return to complying with the inspection requirements of the ASME Code of Record for Nine Mile Point 1 and 2.

5.0 CONCLUSION

Based on its review of the information provided in the licensee's June 8, 2018, submittal for Relief Requests 15R-03 and 14R-03, the NRC staff concludes that the licensee's proposed alternative to implement the BWRVIP l&E guidelines in lieu of the ASME Code, Section XI, Category B-N-1 and B-N-2 examination requirements will ensure that the integrity of the RPV

interior surfaces, attachments, and core support structure is maintained with an acceptable level of quality and safety.

Therefore, pursuant to 10 CFR 50.55a(z)(1), the licensee's proposed alternative is authorized for the fifth and fourth 10-year ISi intervals at Nine Mile Point 1 and 2, respectively, with the condition that in the event the licensee wishes to take exceptions to, or deviations from, the NRC staff-approved BWRVIP l&E guidelines authorized in this alternative, the licensee must revise and resubmit its request for authorization to use the proposed alternative under 10 CFR 50.55a.

All other ASME Code, Section XI requirements for which relief was not specifically requested and approved remain applicable, including third-party review by the Authorized Nuclear lnservice Inspector. Any ASME Code, Section XI RVI components that are not included within the scope of these requests for alternative shall continue to be inspected in accordance with the ASME Code, Section XI requirements, and the l&E guidelines addressed in the applicable BWRVIP reports shall continue to be implemented for the non-ASME Code, Section XI RVI components at Nine Mile Point 1 and 2.

Principal Contributor: 0. Yee Date: December 1 3 , 201 8

B. Hanson

SUBJECT:

NINE MILE POINT NUCLEAR STATION, UNITS 1 AND 2-ALTERNATIVE RELIEF REQUESTS RE: USE OF BOILING WATER REACTOR VESSEL AND INTERNALS PROJECT GUIDELINES IN LIEU OF SPECIFIC ASME CODE REQUIREMENTS (EPID L-2018-LLR-0085) DATED DECEMBER 13, 2018 DISTRIBUTION:

PUBLIC PM File Copy RidsACRS_MailCTR Resource RidsNrrDorlLpl1 Resource RidsNrrDmlrMvib Resource RidsNrrLALRonewicz Resource RidsNrrPMNineMilePoint Resource RidsRgn1 MailCenter Resource JBowen, OEDO CCook, OEDO LBurkhart, OEDO OYee, NRR ADAMS Access1on No.: ML18318A275 *b1y e-ma1*1 OFFICE NRR/DORL/LPL 1/PM NRR/DORL/LPL 1/LA NRR/DMLR/MVIB/BC*

NAME JTobin LRonewicz DAIiey DATE 11/29/2018 12/04/2018 08/03/2018 OFFICE NRR/DORL/LPL 1/BC NRR/DORL/LPL 1/PM NAME JDanna JTobin DATE 12/11/2018 12/13/2018 OFFICIAL RECORD COPY

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