CNL-24-072, Request for Alternative to Extend First Containment Inservice Inspection Interval

Request for Alternative to Extend First Containment Inservice Inspection Interval

ML24347A035
Person / Time
Site:	Watts Bar
Issue date:	12/12/2024
From:	Hulvey K Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
CNL-24-072
Download: ML24347A035 (1)

Text

1101 Market Street, Chattanooga, Tennessee 37402 CNL-24-072 December 12, 2024 10 CFR 50.55a ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-001 Watts Bar Nuclear Plant, Unit 2 Facility Operating License No. NPF-96 NRC Docket No. 50-391

Subject:

Watts Bar Nuclear Plant, Unit 2 - Request for Alternative to Extend First Containment Inservice Inspection Interval In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a, Codes and standards, paragraph (z)(1), the Tennessee Valley Authority (TVA) is requesting an alternative from the requirements of 10 CFR 50.55a(g)(4)(ii) for the Watts Bar Nuclear Plant (WBN), Unit 2 Containment Inservice Inspection (CISI) Program interval end date to align with the TVA fleet, including WBN Unit 1, interval end dates. Currently, all seven TVA units CISI programs utilize the 2013 Edition of the American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code, and six of the seven units share the same start and end dates of September 9, 2018, through September 9, 2028, for the current CISI interval.

However, based on the timing of the WBN Unit 2 commercial operation, the WBN Unit 2 first interval start and end dates are October 19, 2016, to October 19, 2026.

The proposed alternative is to allow the WBN Unit 2 CISI interval end date to extend to September 8, 2028, to align with the other TVA units, utilizing the 2013 Edition of ASME Section XI Code, which provides an acceptable level of quality and safety. This will ensure TVAs fleet CISI programs are on the same ASME Section XI Code Edition going forward. This request for alternative is specific to the CISI program only. This request does not include ASME Section XI Class 1, 2, or 3 components. This request also does not include the pressure testing program or repair/replacement programs. The proposed request for WBN Unit 2 would utilize the 2013 Edition of ASME Section XI Code through the extension period.

U.S. Nuclear Regulatory Commission CNL-24-072 Page 2 December 12, 2024 There are no new regulatory commitments in this letter. Please address any questions regarding this request to Amber V. Aboulfaida, Senior Manager, Fleet Licensing, at avaboulfaida@tva.gov.

Respectfully, Kimberly D. Hulvey General Manager, Nuclear Regulatory Affairs & Emergency Preparedness

Enclosure:

Watts Bar Nuclear Plant, Unit 2, American Society of Mechanical Engineers, Boiler and Pressure Vessel Code,Section XI, Request for Alternative, WBN-2-ISI-02 cc (Enclosure):

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Watts Bar Nuclear Plant NRC Project Manager - Watts Bar Nuclear Plant Digitally signed by Edmondson, Carla Date: 2024.12.12 08:05:59

-05'00'

Enclosure CNL-24-072 E 1 of 4 Watts Bar Nuclear Plant, Unit 2 American Society of Mechanical Engineers, Boiler and Pressure Vessel Code,Section XI, Request for Alternative, WBN-2-ISI-02 I.

ASME Code Component(s) Affected Code Class:

MC

Reference:

10 CFR 50.55a(g)(4)(ii)

IWA-2430 IWA-2431 IWE-2411(a)

Table IWE-2411-1 Examination Category:

All IWE Item Number:

All IWE

==

Description:==

Synchronization of the Containment Inservice Inspection (CISI) Program Interval for Class MC Components and their Integral Attachments to Coincide with the CISI Interval of the TVA fleet Component Number:

Class MC Components II.

Unit Inspection Interval Applicability Plant:

Watts Bar Nuclear Plant (WBN), Unit 2 Commercial Operation Date:

October 19, 2016 Current Interval:

First (1st) 10-year Interval Next Scheduled Interval Start Date:

October 19, 2026 III.

Applicable Code Edition The first Interval of the WBN Unit 2 CISI Program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code,Section XI, 2013 Edition, Subsections IWA and IWE.

IV.

Applicable Code of Federal Regulations and ASME Section XI Requirements 10 CFR 50.55a(g)(4)(ii) - states that Applicable ISI Code: Successive code of record intervals. Inservice examination of components and system pressure tests conducted during successive code of record intervals must comply with the requirements of the latest edition and addenda of the ASME BPV Code incorporated by reference in paragraph (a) of this section no more than 18 months before the start of the code of record interval (or the optional ASME Code Cases listed in NRC Regulatory Guide 1.147, when using ASME BPV Code,Section XI, or NRC Regulatory Guide 1.192, when using the ASME OM Code, as incorporated by reference in paragraphs (a)(3)(ii) and (iii) of this section), subject to the conditions listed in paragraph (b) of this section.

Subsection IWA-2430(b) requires that The inspection interval shall be determined by calendar years following placement of the plant into commercial service.

Subsection IWA-2430(c)(1) requires, in part, that Each inspection interval may be extended by as much as 1 year and may be reduced without restriction, provided the examinations required for the interval have been completed. Successive intervals shall not extend more than 1 year beyond the original pattern of 10-year intervals and shall not exceed 11 years in length.

Enclosure CNL-24-072 E 2 of 4 Subsection IWA-2430(c)(3) requires that That portion of an inspection interval described as an inspection period may be extended by as much as 1 year and may be reduced without restriction, provided the examinations required for that period have been completed. This adjustment shall not alter the requirements for scheduling inspection intervals.

Subsection IWA-2431(a) requires that 1st Inspection Interval - 10 years following initial start of plant commercial service.

Subsection IWE-2411(a) requires, in part, that Examinations shall be completed during each successive inspection interval, in accordance with Table IWE-2411-1.

Table IWE-2411-1 establishes an inspection interval to consist of three periods that shall conclude at the end of years 3, 7, and 10 within the inspection interval. This table defines a CISI interval to be 10 years in duration.

V.

Reason for Request

Pursuant to 10 CFR 50.55a(z)(1), Tennessee Valley Authority (TVA) requests authorization to use an alternative to the timetable required by ASME Section XI and the Code of Federal Regulations (CFR) to extend the first WBN Unit 2 CISI Program inspection interval by approximately 23 months from October 18, 2026, to align with the end of the third CISI Program interval for WBN Unit 1, Sequoyah Nuclear Plant Units 1 and 2, and Browns Ferry Nuclear Plant Units 1, 2, and 3, which are scheduled to end September 8, 2028. It is intended that, following completion of the extended interval, the subsequent Unit 2 CISI interval be reset, such that the Code allowable one year extension would remain available for future intervals. To align the fleet, the proposed start date for the second WBN Unit 2 CISI inspection interval is proposed to be September 9, 2028. This will ensure CISI inspection intervals and Code editions are aligned going forward.

WBN Unit 2 entered commercial operation on October 19, 2016. This commercial service date established the initial CISI interval for WBN Unit 2. WBN Unit 1, and the other units in TVAs fleet, entered commercial operation prior to September 9, 1998, such that the effective date of the applicable 10 CFR 50.55a rule that mandated implementation of a CISI Program, per Federal Register 61FR41303, defined the CISI interval start dates. The current end date for the first CISI inspection interval for WBN Unit 2 is October 18, 2026, with the end date for the CISI inspection interval for the other TVA units being September 8, 2028. Per the requirements of 10 CFR 50.55a(g)(4)(ii), successive intervals must comply with the latest edition and addenda of the ASME BPV Code. Also per IWA-2430(c)(1) of ASME Section XI Code Edition 2013, inspection intervals may be extended by as much as one year. However, compliance with these requirements will place the WBN Unit 2 CISI Program on a different Code of Record than WBN Unit 1 and the rest of the TVA fleet, based on the interval dates mentioned above. This creates an error-likely situation in managing the WBN Unit 1 and 2 programs if they are on different Code editions and affects TVAs ability to share resources utilizing standardized programs. Currently, the WBN CISI Program is managed by one centralized fleet procedure and one site implementing instruction that includes rules for both Units 1 and 2 on the same Code of Record. Therefore, in accordance with regulation 10 CFR 50.55a(z)(1), TVA requests an alternative to the ASME Code and CFR requirements to extend the WBN Unit 2 CISI interval by approximately 23 months while still using the 2013 Edition of ASME Section XI. Both WBN units will then update to the latest endorsed edition of the ASME Section XI Code 18 months prior to the end of the interval (September 8, 2028), in accordance with 10 CFR 50.55a(g)(4)(ii).

This will enable both WBN units to work under one ASME Section XI Code Edition for CISI.

Enclosure CNL-24-072 E 3 of 4 This alternative is specific to the CISI Program only. This request does not include ASME Section XI Code Class 1, 2, or 3 components. This request also does not include the pressure testing program or repair/replacement programs. The proposed request for WBN Unit 2 would utilize the 2013 Edition of ASME Section XI Code through the extension period.

Extending the ASME Section XI CISI inspection interval for WBN Unit 2 to align with WBN Unit 1 and the TVA fleet reduces the administrative burden of complying with two different editions of ASME Section XI Code and reduces the possibility of working to the wrong procedures or documents as they would all be written to the same Code edition of Section XI.

This will also ensure that going forward the CISI inspection interval updates for WBN will take place at the same time. The proposed alternative does not result in a reduction of examinations for either unit, as the WBN Unit 2 schedule will be revised to capture the exams listed in the below Section VI during the extension timeframe. This proposal does not alter the WBN Unit 1 CISI schedule.

The proposed alternative as described herein provides an acceptable level of quality and safety, and does not adversely impact the health and safety of the public.

VI.

Proposed Alternative and Basis for Use TVA proposes WBN Unit 2 extension of the current first CISI interval end date by approximately 23 months from October 18, 2026, to September 8, 2028, and to reset the cadence of subsequent CISI intervals to this same date, such that both units at WBN start their next subsequent CISI inspection intervals on September 9, 2028. Examinations performed after this date will be performed to procedures complying with the selected edition of ASME Section XI Code in accordance with 10 CFR 50.55a(g)(4)(ii).

In lieu of the requirements specified in Section IV of this request, TVA proposes the following alternatives:

1. The WBN Unit 2 first CISI interval duration will be modified to end on September 8, 2028, in order to coincide with the WBN Unit 1 and TVA fleet CISI interval. Subsequent CISI intervals will follow all requirements specified within and allowed by IWA-2430, based on the applicable ASME Section XI Code Edition as defined by the start date of the CISI interval and the governing regulation at that time (e.g., 18 months prior to the start of the successive interval and then similarly for subsequent intervals).

2. Subsequent CISI intervals will comply with the applicable requirements of ASME Section XI Code as specified by 10 CFR 50.55a, including any applicable conditions in 10 CFR 50.55a(b)(2), based on the sequencing of intervals from the new synchronized CISI interval date. Administrative procedures, non-destructive examination procedures, and CISI documents will be updated to meet the requirements of the selected edition of Section XI Code on September 9, 2028. All requirements of the new CISI Program will be implemented at that time.

3. There are two refueling outages (Cycle 7 and Cycle 8) for WBN Unit 2 that are scheduled to occur between October 18, 2026, and September 8, 2028. This change adds a fourth period with these dates to ensure that the structural integrity of the steel containment vessel is monitored and maintained. To ensure that there is not a gap of examinations during the approximate 23 month extension, WBN Unit 2 will revise its CISI schedule to perform the periodically required examinations during this extension period as follows.

Enclosure CNL-24-072 E 4 of 4

a. E-A, E1.11 - General visual examinations of 100 percent of the accessible surface areas will be completed during one of the two listed refueling outages above.

b. E-A, E1.31 - General visual examinations of 100 percent of the moisture barrier seals will be performed during one of the two listed refueling outages above.

c. E-A E1.32 - General visual examinations will be performed on an additional 33 percent of the leak chase channel enclosures during one of the two listed refueling outages above, in accordance with the 2017 Edition of ASME Section XI as required by 10 CFR 50.55a(b)(2)(ix)(k).

d. E-G, E8.10 - For bolted connections, 100 percent of the examination requirements will be completed by the end of the originally scheduled interval for Unit 2. However, any bolted connections that are dissembled during this timeframe, and were not previously examined in the disassembled condition, will be VT-1 examined in the disassembled condition during the extension period.

e. E-C, E4.11 and E4.12 - There are currently no Category E-C components for WBN Unit 2. There have been five refueling outages completed during the first WBN Unit 2 CISI Program interval with no findings, per IWE-1241, that would require augmented examinations. All CISI exams that have been performed in the five completed refueling outages have been satisfactory. However, if there are items added to Category E-C as required by IWE-1241, these items will be examined in one of the two refueling outages mentioned above.

Use of the proposed alternative will allow the use of a common ASME Section XI Code Edition for CISI activities on CISI components, enabling program and inspection procedures to be maintained and implemented to one Code edition. This efficiency will reduce the chance of applying incorrect CISI requirements for component examinations and will support resource sharing for the fleet. Common interval dates and procedures will reduce the administrative burden of performing multiple interval updates and will maintain the quality and safety of the CISI Programs in accordance with the latest regulations, codes, and standards.

For the above reasons, TVA requests this proposed alternative be approved on the basis that it provides an acceptable level of quality and safety, in accordance with 10 CFR 50.55a(z)(1).

VII.

Duration of Proposed Alternative An alternative is requested to extend the WBN Unit 2 first CISI Program interval to the proposed end date (September 8, 2028).

VIII.

Precedent

1. Browns Ferry Nuclear Plant, Units 1, 2 and 3, Alternative Request ISI-45, dated September 12, 2014 (ADAMS Accession No. ML14260A365). NRC authorization dated August 6, 2015 (ADAMS Accession No. ML15191A372).

2. Dresden Nuclear Station, Units 2 and 3, Alternative Requests I6R-09 and I6R-10, dated July 19, 2022 (ADAMS Accession No. ML22200A258). NRC authorization dated January 12, 2023 (ADAMS Accession No. ML23003A178).

IX.

Reference American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, 2013 Edition, Subsections IWA and IWE