RS-21-009, Proposed Relief Request Associated with Code Case N-921
| ML22018A106 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 01/18/2022 |
| From: | David Gudger Exelon Generation Co LLC |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RS-21-009 | |
| Download: ML22018A106 (12) | |
Text
200 Exelon Way Kennett Square, PA 19348 www.exeloncorp.com 10 CFR 50.55a RS-21-009 January 18, 2022 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249 Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265
Subject:
Proposed Relief Request Associated with Code Case N-921 In accordance with 10 CFR 50.55a, "Codes and standards," paragraph (z)(1), Exelon Generation Company, LLC (Exelon) is requesting a proposed alternative to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components and 10 CFR 50.55a(g)(4)(ii),
Applicable ISI Code: Successive 120-month interval, on the basis that the proposed alternative provides an acceptable level of quality and safety. Specifically, this proposed alternative concerns the use of Code Case N-921, Alternative 12-yr Inspection Interval Duration.
Exelon requests approval of the proposed alternative by December 1, 2022.
There are no regulatory commitments contained in this letter.
If you have any questions or require additional information, please contact Tom Loomis at 610-765-5510.
Respectfully, David T. Gudger Sr. Manager - Licensing & Regulatory Affairs Exelon Generation Company, LLC
Attachment:
Relief Request
Proposed Relief Request Associated with Code Case N-921 January 18, 2022 Page 2 cc: Regional Administrator - NRC Region III NRC Senior Resident Inspector - Dresden Nuclear Power Station NRC Senior Resident Inspector - Quad Cities Nuclear Power Station NRC Project Manager - Dresden Nuclear Power Station NRC Project Manager - Quad Cities Nuclear Power Station Illinois Emergency Management Agency - Division of Nuclear Safety
ATTACHMENT RELIEF REQUEST
10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 1 of 9)
Proposed Alternative Associated with Code Case N-921 in Accordance with 10 CFR 50.55a(z)(1)
This proposed alternative is limited to IWA-2430, IWA-2431, and Tables IWB-2411-1, IWC-2411-1, IWD-2411-1, IWE-2411-1, and IWF-2410-1.
- 2. APPLICABLE CODE EDITION AND ADDENDA PLANT INTERVAL EDITION START DATE CURRENT END REVISED END DATE DATE Fifth ISI 2007 Edition, through January 20, 2013 January 19, 2023 January 19, 2025 2008 Addenda Dresden Nuclear Power Station, Units 2 and 3 Third CISI 2013 Edition September 9, 2018 September 8, September 8, 2028 2030 Fifth ISI 2007 Edition, through April 2, 2013 April 1, 2023 April 1, 2025 2008 Addenda Quad Cities Nuclear Power Station, Units 1 and 2 Third CISI 2013 Edition September 9, 2018 September 8, September 8, 2028 2030 Note: Absent rulemaking or other similar subsequently approved Code changes, Dresden and Quad Cities will resubmit this relief for the successive Inservice Inspection (ISI) and Containment Inservice Inspection (CISI) intervals to take advantage of the benefits described below.
- 3. APPLICABLE CODE REQUIREMENTS 10 CFR 50.55a(g)(4)(ii), Applicable ISI Code: Successive 120-month interval, states, in part, that Inservice examination of components and system pressure tests conducted during successive 120-month inspection intervals must comply with the requirements of the latest edition and addenda of the ASME Code incorporated by reference in paragraph (a) of this section 18 months before the start of the 120-month inspection interval.
IWA-2430 - INSPECTION INTERVALS - This section state that the inservice examinations and system pressure tests required by IWB, IWC, IWD, IWE, and inservice examinations and tests of IWF shall be completed during each of the inspection intervals for the service lifetime of the plant. The inspections shall be performed in accordance with the schedule of the Inspection Program of IWA-2431.
IWA-2431 - Inspection Program - The inspection intervals shall comply with the following, except as modified by IWA-2430(c) (and IWA-2430(d) (2013 Edition)):
1st Inspection Interval - 10 years following initial start of plant commercial service Successive Inspection Intervals - 10 years following the previous inspection interval
10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 2 of 9)
Table IWB-2411-1, IWC-2411-1, IWD-2411-1, IWE-2411-1, and IWF-2410 Inspection Program - These Tables provide the calendar years of plant service within the interval for each period (3 years, 7 years,10 years) and the distribution of completed examinations.
- 4. REASON FOR REQUEST Exelon Generation Company, LLC (Exelon) requests approval to implement Code Case N-921.
This Code Case establishes a 12-year inspection interval for inspection programs. This is a marginal extension from a 10-year to 12-year interval which supports a minimum two refueling outages per period and supports improved operational strategies such as skip ISI outages and divisional outages. The divisional outage strategy is based on the concept that one division of safety systems is removed during an outage as compared to swapping between divisions during an outage. The divisional outage strategy enhances safety by reducing the challenges of swapping safety trains during an outage. The minimal change of extending the interval length will not reduce plant safety.
- 5. PROPOSED ALTERNATIVE AND BASIS FOR USE In accordance with 10 CFR 50.55a, "Codes and standards," paragraph (z)(1), Exelon is requesting the use of Code Case N-921 on the basis that the proposed alternative provides an acceptable level of quality and safety.
This proposed alternative is limited to IWA-2430 (including Class CC components - IWL), IWA-2431, and Tables IWB-2411-1, IWC-2411-1, IWD-2411-1, IWE-2411-1, and IWF-2410-1. Note:
neither Dresden nor Quad Cities CISI programs contain any Class CC concrete components inspected in accordance with Subsection IWL.
Currently ASME Section XI breaks up the 10-year inspection interval into (3) periods (typically a 3-4-3 year breakdown for periods). This code case will establish four-year periods (4-4-4 year breakdown) over the course of a 12-year inspection interval. This change supports light water-cooled plants that have transitioned from 18-month refueling cycles to 24-month refueling cycles and ensures each inspection period during a 12-year interval will have at least two refueling outages (2-2-2 format). Based on where each Unit is during the current interval, the initial implementation of the Code Case at Dresden and Quad Cities will not result in 2 outages per period; however, during scheduling of the successive interval there will be 2 outages per period.
This is an improvement over the current 10-year interval for a 24-month refueling cycle plant where one period will have only a single outage to complete examinations (1-2-2, 2-1-2, or 2-2-1 format). Having only a single refueling outage for an inspection period places undue burden on plants to meet required inspection period percentage requirements as well as completing all required periodic examination and testing within a single outage. The current 10-year interval allows as little as 16% of exams to be performed in a period with a single outage; however, this still does not eliminate exam categories where 100% examination is required each period.
Examples of this hardship are completing all required outage pressure tests within a single outage (Class 2/Class 3 periodic pressure tests conducted only during outages) and having only a single outage to complete all required periodic IWE exams requirements (Containment General visual exams and moisture barrier exams accessible only during outages).
Also, for inspection periods with a single outage, this requires additional trains/divisions of equipment to be removed from service or aligned to facilitate periodic exams for that outage.
This results in a reduction of train availability and safety equipment. Many plants have gone to train-specific outage where most of the work is only performed on a single train/division in
10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 3 of 9) order to minimize train swaps and complex operational alignments. Having only a single outage in an inspection period can place burden to complete the required inspections if they do not align with the outage train/division. Having at least two outages per period will ensure train and division outage schedules can be properly planned and aligned with the needed ISI exams.
Also, not having to perform all required periodic examinations within a single refueling outage will give the plant additional flexibility and optimization of the required resources.
Since the inception of ASME Section XI, the Augmented Inservice Inspection Programs and site-specific commitments based on operating experience have vastly grown and have well established requirements and basis for examinations. These examinations are often focused on specific degradation mechanisms and concentrate on the most relevant operating experience within the industry. These examinations are not necessarily driven or required by the ASME Section XI Code and these augmented examinations will continue to be scheduled in accordance with the stations augmented inspection programs during the extended interval. The performance of these augmented exams provides additional assurance that the reactor coolant pressure boundary is maintained even if ASME Section XI Code required exams are extended from 10 to 12 years. Also, VT-2 visual examinations associated with the Class 1 system leakage test will be performed each refueling outage regardless of interval length; therefore, the ongoing augmented ISI exams along with the ongoing leakage tests every refueling outage provide adequate assurance that structural integrity is being maintained for a 12-year inspection interval.
The proposed alternative does not impact inspections required to be performed prior to the end of the license renewal period.
The relief requests applicable to the current interval that are based on a 10-year inspection frequency will be scheduled and performed on the required 10-year frequency during the extended interval. Enclosure 1 contains a listing of the relief requests for the fifth ISI and third CISI interval at Dresden and Quad Cities that will be extended from 10 to 12 years.
Based on over four decades of operating experience for Dresden and Quad Cities, extending the interval from 10 years to 12 years will have negligible impact to safe operation of the plant or the health and safety of the public. Extending the interval will minimize train/loop swaps to perform the exams, minimize plant operational concerns, and as a result, enhance plant safety.
Dresden and Quad Cities will continue to perform augmented ISI exams, Class 1 system leakage tests, and required 10-year inspection frequency exams to further ensure plant and public safety.
Conclusion Based on current ISI examination and testing requirements, the proposed alternative will better synchronize future inspection periods within a 12-year Interval with improved operational strategies adopted industry wide while having a negligible effect on plant safety. This allows plants the ability to better align periodic examinations with scheduled maintenance during a train/division specific refueling outage. Based on the reasons mentioned above, extending an ISI interval from 10 to 12 years will allow the plants greater flexibility to align and perform future ISI examinations while maintaining safe plant operations. Accordingly, the proposed alternative will provide an acceptable level of quality and safety.
10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 4 of 9)
- 6. DURATION OF PROPOSED ALTERNATIVE The proposed alternative will be applicable for the remainder of each plant's extended ISI and CISI inspection interval as specified in Section 2 or until such time as the NRC approves a similar administrative requirement relaxation in an NRC approved applicable Code Edition in 10 CFR 50.55a or a Code Case in Regulatory Guide 1.147.
- 7. PRECEDENTS None
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Enclosure 1 Fifth Interval Relief Requests Relief Requests and Letters to Approve Later Editions of the ASME Code Associated with the Fifth ISI Interval and Third CISI Interval for Dresden Nuclear Power Station, Units 2 and 3 Description Date Submitted / ML# Date Approved / ML#
Extension of Relief for Alternative February 23, 2004 March 23, 2005 Reactor Pressure Vessel (ML040620661) (ML050620359)
Circumferential Weld Examinations for (Authorized for the 20-year Additional License Operating Period. extended operation)
Inspection of Standby Liquid Control September 28, 2012 September 30, 2013 Nozzle Inner Radius. (ML12275A069), as (ML13258A003, supplemented by letters ML13260A585)
November 19, 2012 (ML123250319),
June 3, 2013 (ML13154A248)
Alternate Risk Informed Selection and September 28, 2012 September 30, 2013 Examination Criteria for Examination (ML12275A069), as (ML13258A003, Categories B-F, B-J, C-F-1, and C-F- supplemented by letters dated ML13260A585) 2 Pressure Retaining Piping Welds. November 28, 2012 (ML12333A263)
June 3, 2012 (ML13154A248)
Continuous Pressure Monitoring of September 28, 2012 September 30, 2013 the Control Rod Drive (CRD) System (ML12275A069), as (ML13258A003, Accumulators. supplemented by letters dated ML13260A585)
Use of BWRVIP Guidelines in Lieu of September 28, 2012 September 30, 2013 Specific ASME Code Requirements (ML12275A069), as (ML13258A003, on Reactor Pressure Vessel Internals supplemented by letter dated ML13260A585) and Components Inspection. November 19, 2012 (ML123250319)
Alternative for Inspection of Nozzle- June 30, 2016 June 28, 2017 to-Vessel Shell Welds and Nozzle (ML16187A295), as (ML17073A121)
Inner Radius Sections of RPV supplemented by letter dated Nozzles. August 22, 2016 (ML16235A0850)
Alternative for Examination of ASME October 31, 2016 June 26, 2017 Section XI, Examination Category B- (ML16306A270) as supplemented (ML17170A13)
G-1, Item Number B6.40, Threads in by letter dated April 3, 2017 Flange. (ML17093A883)
10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 6 of 9)
Description Date Submitted / ML# Date Approved / ML#
Proposed Alternative to Utilize Code May 30, 2018 July 18, 2019 Cases N-878 and N-880. (ML18151A028) as supplemented (ML19192A244) by letters dated July 26, 2018 (ML18208A345),
January 8, 2019 (ML19008A187),
May 1, 2019 (ML19122A307),
June 4, 2019 (ML19155A214)
Use of Encoded Phased Array February 15, 2019 September 27, 2019 Ultrasonic Examination Techniques In (ML19049A001) (ML19269C543)
Lieu of Radiography. as supplemented by letter dated June 25, 2019 (ML19176A343)
Revision to Relief Requests February 19, 2019 April 30, 2019 Associated with the Use of the (ML19050A363) (ML19098A034)
BWRVIP Guidelines in Lieu of Specific ASME Code Requirements on Reactor Pressure Vessel Internals and Components Inspection.
Request to Use a Portion of a Later August 27, 2019 April 17, 2020 Edition of the ASME B&PV Code, (ML19239A208) (ML20099D955)
Section XI.
Testing Frequency for Isolation November 12, 2019 January 13, 2020 Condenser Shell Side and Vent Piping. (ML19340A095) (ML20008D276)
Request to Use Provisions of a Later September 2, 2020 September 30, 2020 Edition of the ASME Boiler and (ML20246G735) as (ML20269A200)
Pressure Vessel Code, Section XI, supplemented by letter dated IWA-4540(b). September 24, 2020 (ML20268A984)
Request to Use Provisions of a Later September 2, 2020 February 3, 2021 Edition of ASME Boiler and Pressure (ML20246G739) as (ML21028A673)
Vessel Code, Section XI (IWA-5120). supplemented by letters dated September 24, 2020 (ML20268A984)
Proposed Alternative Concerning December 1, 2020 August 5, 2021 ASME Section XI (ML20336A008) as supplemented (ML21216A220)
Repair/Replacement Documentation by letters dated for Replacement of Pressure April 20, 2021 Retaining Bolting. ML21110A092),
May 18, 2021 (ML21138A839),
July 7, 2021 (ML21188A242)
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Description Date Submitted / ML# Date Approved / ML#
Proposed Alternative to Utilize Code January 4, 2021 June 25, 2021 Cases N-878 and N-880 (include (ML21004A066) (ML21166A168) carbon steel piping).
Proposed Relief Request Associated August 12, 2021 Currently being reviewed with RPV Water Level Instrument (ML21224A123) by NRC.
(WLI) Partial Penetration Nozzle Repairs.
Relief Requests and Letters to Approve Later Editions of the ASME Code Associated with the Fifth ISI Interval and Third CISI Interval for Quad Cities Nuclear Power Station, Units 1 and 2 Description Submittals / ML# Date Approved /
ML#
Extension of Relief for Alternative February 23, 2004 March 23, 2005 Reactor Pressure Vessel (ML040620661) (ML050620359)
Circumferential Weld Examinations for (Authorized for the 20-Additional License Operating Period. year extended operation)
Inspection of Standby Liquid Control September 28, 2012 September 30, 2013 Nozzle Inner Radius. (ML12275A070) (ML13267A097) as supplemented by letters dated November 28, 2012 (ML12333A262),
May 30, 2013 (ML13151A107)
Alternate Risk Informed Selection and September 28, 2012 September 30, 2013 Examination Criteria for Examination (ML12275A070) (ML13267A097)
Categories B-F, B-J, C-F-1, and C-F-2 as supplemented by letters dated Pressure Retaining Piping Welds. November 28, 2012 (ML12333A263),
May 30, 2013 (ML13123A086)
Continuous Pressure Monitoring of the September 28, 2012 September 30, 2013 Control Rod Drive (CRD) System (ML12275A070) as (ML13267A097)
Accumulators. supplemented by letters dated January 24, 2013 (ML13025A161)
Use of BWRVIP Guidelines in Lieu of September 28, 2012 September 30, 2013 Specific ASME Code Requirements on (ML12275A070) as (ML13267A097)
Reactor Pressure Vessel Internals and supplemented by letters dated Components Inspection. May 30, 2013 (ML13151A107)
Use of ASME Code Case N-513-3, March 28, 2014 March 19, 2015 Evaluation Criteria for Temporary (ML14090A140) (ML15043A496)
Acceptance of Flaws in Moderate as supplemented by letters dated Energy Class 2 or 3 Piping, at Higher October 29, 2014 System Operating Pressure. (ML14303A463),
10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 8 of 9)
Description Submittals / ML# Date Approved /
ML#
February 5, 2015 (ML15036A487)
Alternative for Examination of ASME October 31, 2016 June 26, 2017 Section XI, Examination Category B- (ML16306A270) as (ML17170A13)
G-1, Item Number B6.40, Threads in supplemented by letter dated Flange. April 3, 2017 (ML17093A883)
Alternative for Inspection of Nozzle-to- December 19, 2016 August 25, 2017 Vessel Shell Welds and Nozzle Inner (ML16354A749) (ML17221A264)
Radius Sections of RPV Nozzles (ASME Code Case N-702).
Quad Cities Generating Station Unit 2, February 14, 2017 January 24, 2018 Relief for the Unit 2 Reactor Pressure (ML17045A681), (ML18022A616)
Vessel Penetration N-11B Repair. as supplemented by letter dated (The NRC authorizes the January 4, 2018 use of proposed (ML18004B515) alternatives for QCNPS, Unit 2, through Cycle 27 currently scheduled to end in spring 2024, not to exceed 9 years from the spring 2016 outage when the demonstrated NDE was last performed.
Proposed Alternative to Utilize Code May 30, 2018 July 18, 2019 Cases N-878 and N-880. (ML18151A028) as (ML19192A244) supplemented by letters dated July 26, 2018 (ML18208A345),
January 8, 2019 (ML19008A187),
May 1, 2019 (ML19122A307),
June 4, 2019 (ML19155A214)
Use of Encoded Phased Array February 15, 2019 September 27, 2019 Ultrasonic Examination Techniques In (ML19049A001) (ML19269C543)
Lieu of Radiography. as supplemented by letter dated June 25, 2019 (ML19176A343)
Revision to Relief Requests February 19, 2019 April 30, 2019 Associated with the Use of the (ML19050A363) (ML19098A034)
BWRVIP Guidelines in Lieu of Specific ASME Code Requirements on Reactor Pressure Vessel Internals and Components Inspection.
Request to Use a Portion of a Later August 27, 2019 April 17, 2020 Edition of the ASME B&PV Code, (ML19239A208) (ML20099D955)
Section XI.
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Description Submittals / ML# Date Approved /
ML#
Request to Use Provisions of a Later September 2, 2020 September 30, 2020 Edition of the ASME Boiler and (ML20246G735) as (ML20269A200)
Pressure Vessel Code, Section XI, supplemented by letter dated IWA-4540(b). September 24, 2020 (ML20268A984)
Request to Use Provisions of a Later September 2, 2020 February 3, 2021 Edition of ASME Boiler and Pressure (ML20246G739) as (ML21028A673)
Vessel Code, Section XI (IWA-5120). supplemented by letter dated September 24, 2020 (ML20268A984)
Proposed Alternative Concerning December 1, 2020 August 5, 2021 ASME Section XI Repair/Replacement (ML20336A008) as (ML21216A220)
Documentation for Replacement of supplemented by letters dated Pressure Retaining Bolting. April 20, 2021 ML21110A092),
May 18, 2021 (ML21138A839),
July 7, 2021 (ML21188A242)
Proposed Alternative to Utilize Code January 4, 2021 June 25, 2021 Cases N-878 and N-880 (include (ML21004A066) (ML21166A168) carbon steel piping).
Proposed Relief Request Associated August 12, 2021 Currently being reviewed with RPV Water Level Instrument (ML21224A123) by NRC.
(WLI) Partial Penetration Nozzle Repairs.