CNL-24-010, License Amendment Request to Recapture Low-Power Testing Time (WBN-TS-23-19)

License Amendment Request to Recapture Low-Power Testing Time (WBN-TS-23-19)

ML24108A015
Person / Time
Site:	Watts Bar
Issue date:	04/17/2024
From:	Hulvey K Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
CNL-24-010
Download: ML24108A015 (1)

Text

1101 Market Street, Chattanooga, Tennessee 37402 CNL-24-010 April 17, 2024 10 CFR 50.90 10 CFR 50.51 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 1 Facility Operating Licenses No. NPF-90 NRC Docket No. 50-390

Subject:

License Amendment Request to Recapture Low-Power Testing Time (WBN-TS-23-19)

In accordance with the provisions of Title 10 of the Code of Federal Regulations (10 CFR) 50.90, "Application for amendment of license, construction permit, or early site permit," Tennessee Valley Authority (TVA) is submitting a request for an amendment to Facility Operating License No. NPF-90 for the Watts Bar Nuclear Plant (WBN), Unit 1.

The current expiration date of the WBN Unit 1 operating License (OL) of November 9, 2035, was based on 40 years from the date of issuance of the WBN Unit 1 low-power operating license (LPOL) of November 9, 1995. The proposed change would revise the expiration date of the WBN Unit 1 OL such that it would expire 40 years from the date of issuance of the full-power operating license (FPOL) of February 7, 1996, as opposed to 40 years from the date of the LPOL as permitted by 10 CFR 50.51. The proposed change would extend the WBN Unit 1 OL by 90 days and would expire on February 7, 2036.

In the Staff Requirements Memorandum (SRM) for SECY-98-296, "Agency Policy Regarding Licensee Recapture of Low-Power Testing or Shutdown Time for Nuclear Power Plants," dated March 30, 1999, the Nuclear Regulatory Commission (NRC) established policy regarding recapture of low-power testing time for nuclear power plants. Specifically, the NRC approved the plan to grant license amendment requests to amend the expiration dates of certain licenses to recover time spent in low-power testing before issuance of an FPOL. As discussed in the enclosure to this submittal, this license amendment request falls within the scope of that policy.

The enclosure to this submittal provides a description and technical evaluation of the proposed change, a regulatory evaluation, and a discussion of environmental considerations. Attachment 1 to the enclosure provides the existing WBN Unit 1 OL marked up to show the proposed change.

U.S. Nuclear Regulatory Commission CNL-24-010 Page 2 April 17, 2024 TVA has determined that there are no significant hazards considerations associated with the proposed change and that the change qualifies for a categorical exclusion from environmental review pursuant to the provisions of 10 CFR 51.22(c)(9). In accordance with 10 CFR 50.91(b)(1), TVA is sending a copy of this letter and enclosure to the Tennessee State Department of Environment and Conservation.

TVA requests approval of the proposed license amendment within one year from the date of submittal, with implementation within 30 days of issuance of the amendment.

There are no new regulatory commitments associated with this submittal. Please address any questions regarding this request to Stuart L. Rymer, Senior Manager, Fleet Licensing, at slrymer@tva.gov.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 17th day of April 2024.

Respectfully, Kimberly D. Hulvey Director, Nuclear Regulatory Affairs Enclosure Description and Assessment of the Proposed Change cc: (Enclosure):

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Watts Bar Nuclear Plant NRC Project Manager - Watts Bar Nuclear Plant Director, Division of Radiological Health - Tennessee State Department of Environment and Conservation Digitally signed by Edmondson, Carla Date: 2024.04.17 07:01:13 -04'00'

Enclosure CNL-24-010 E-1 of 12 Description and Assessment of the Proposed Change

Subject:

License Amendment Request to Recapture Low-Power Testing Time (WBN-TS-23-19)

CONTENTS 1.0

SUMMARY

DESCRIPTION........................................................................................ 2 2.0 DETAILED DESCRIPTION........................................................................................ 2 2.1 Reason for the Proposed Change....................................................................... 2 2.2 Description of the Proposed Change................................................................... 3

3.0 TECHNICAL EVALUATION

....................................................................................... 3 3.1 Safety Assessment of Reactor Pressure Vessel................................................. 3 3.2 Structures............................................................................................................ 5 3.3 Mechanical Equipment........................................................................................ 7 3.4 Electrical Equipment............................................................................................ 7 3.5 Quality Assurance and Maintenance Programs................................................... 8 3.6 Conclusion........................................................................................................... 8

4.0 REGULATORY EVALUATION

................................................................................... 8 4.1 Applicable Regulatory Requirements and Criteria............................................... 8 4.2 Precedent............................................................................................................ 9 4.3 No Significant Hazards Consideration Analysis................................................... 9 4.4 Conclusions....................................................................................................... 11

5.0 ENVIRONMENTAL CONSIDERATION

.................................................................... 11

6.0 REFERENCES

......................................................................................................... 11 Attachment

1. Proposed Change to Operating License (Mark-Up) for WBN Unit 1

Enclosure CNL-24-010 E-2 of 12 1.0

SUMMARY

DESCRIPTION In accordance with the provisions of Title 10 of the Code of Federal Regulations (10 CFR) 50.90, "Application for amendment of license, construction permit, or early site permit,"

Tennessee Valley Authority (TVA) is submitting a request for an amendment to Facility Operating License No. NPF 90 for the Watts Bar Nuclear Plant (WBN), Unit 1.

The current expiration date of the WBN Unit 1 operating License (OL) of November 9, 2035, was based on 40 years from the date of issuance of the WBN Unit 1 low-power operating license (LPOL) of November 9, 1995. The proposed change would revise the expiration date of the WBN Unit 1 OL such that it would expire 40 years from the date of issuance of the full-power operating license (FPOL) of February 7, 1996, as opposed to 40 years from the date of the LPOL as permitted by 10 CFR 50.51. The proposed change would extend the WBN Unit 1 OL by 90 days and would expire on February 7, 2036.

2.0 DETAILED DESCRIPTION 2.1 Reason for the Proposed Change Section 103.c of the Atomic Energy Act of 1954 (AEA), as amended, provides that the term of a license issued under that section "not exceeding forty years from the authorization to commence operations." Also 10 CFR 50.51(a) specifies that "Each license will be issued for a fixed period of time to be specified in the license but in no case to exceed 40 years from date of issuance." Additionally, 10 CFR 50.56 and 10 CFR 50.57 allow the issuance of an OL pursuant to 10 CFR 50.51 after the construction of the facility has been substantially completed, in conformity with the construction permit and when other provisions specified in 10 CFR 50.57 are met.

The Nuclear Regulatory Commission (NRC) issued an LPOL for WBN Unit 1 on November 9, 1995 (NPF-20), pursuant to AEA Section 103 and 10 CFR 50 (Reference 1).

The low-power testing license limited plant operation to power levels not exceeding five percent of full power. The low-power testing license was then superseded by the FPOL, issued by the NRC on February 7, 1996 (NPF-90) (Reference 2), also pursuant to AEA Section 103 and 10 CFR Part 50. However, the FPOL included an expiration date of November 9, 2035; which is 40 years after issuance of the LPOL, versus 40 years after issuance of the FPOL. The proposed amendment would recapture the time spent in low-power testing by extending the FPOL's current expiration date by 90 days to February 7, 2036.

In the Staff Requirements Memorandum (SRM) for SECY-98-296, "Staff Requirements -

SECY-98-296 - Agency Policy Regarding Licensee Recapture of Low-Power Testing or Shutdown Time for Nuclear Power Plants," dated March 30, 1999 (Reference 3), the Commission established NRC policy regarding recapture of low-power testing time for nuclear power plants. Specifically, the Commission approved the NRC staff's plan to grant a license amendment to the Grand Gulf Nuclear Station, Unit 1 (GGNS) licensee to amend the expiration date of the GGNS license to recover time spent in low-power testing before receipt of its FPOL. The Commission also approved future license amendment requests from other similarly-situated licensees (i.e., licensees that were issued FPOLs with 40-year license terms commencing on the date of issuance of separate, previously-granted low-power testing licenses). This license amendment request (LAR) falls within the scope of that policy.

Enclosure CNL-24-010 E-3 of 12 Aging effects are not safety-significant because the license recapture period (i.e., 90 days for WBN Unit 1) is short when compared to the overall license period. Additionally, as described in Section 4.3 below, the proposed amendment to the facility operating license presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.

2.2 Description of the Proposed Change The proposed change revises the expiration date of the WBN Unit 1 OL from November 9, 2035, to February 7, 2036. to the enclosure provides the existing WBN Unit 1 OL marked up to show the proposed change.

3.0 TECHNICAL EVALUATION

The proposed amendment would revise the expiration of the facility operating license such that the expiration date of the 40-year OL is calculated from the issuance date of the FPOL rather than the issuance date of the LPOL. As described above, the Commission has established a policy of granting license amendments to recover time spent in low-power testing within their FPOL. The request to recapture low-power testing time for WBN Unit 1 falls within the scope of this Commission policy.

WBN Unit 1 was designed and constructed to ensure at least a 40-year service life. Design features allow for routine inspection of structures, systems, and components during this service life in accordance with NRC requirements and TVA procedures. Surveillance, inspection, and maintenance practices, which have been implemented in accordance with the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV)

Code and the WBN Unit 1 Technical Specifications (TS), provide assurance that any degradation in plant safety-related equipment will be identified and corrected to provide continued safe operation of the unit throughout the duration of the facility operating license, including the proposed license extension (i.e., low-power testing recapture) period.

3.1 Safety Assessment of Reactor Pressure Vessel WBN Unit 1 was designed, licensed, and constructed for 40 years of operation as discussed in various places in the WBN dual-unit Updated Final Safety Analysis Report (UFSAR).

This 40-year design life presumed operation at a rated thermal power level of 3459 megawatts thermal with a cumulative lifetime capacity factor of 80%, or 32 effective full power years (EFPY). As of the end of Cycle 18 in spring 2023, the WBN Unit 1 reactor pressure vessel (RPV) had accumulated an exposure of 24.3 EFPY, which is equivalent to a cumulative capacity factor of greater than 89% over the lifetime of the plant up to that point. Based on this operating history and the expected future operation of the plant, an exposure of 32 EFPY will be achieved prior to the end of the FPOL, even without the proposed 90-day license recapture period. The WBN Unit 1 RPV integrity analyses of record, which are currently based on an assumed reactor vessel exposure of 32 EFPY, will therefore be updated and documented in the WBN Unit 1 Pressure and Temperature Limits Report (PTLR) prior to the reactor achieving an actual exposure of 32 EFPY, and will bound the 40-year FPOL period, including the proposed 90 day license recapture period.

Enclosure CNL-24-010 E-4 of 12 The WBN Unit 1 RPV is discussed in Section 5.4 of the WBN dual-unit UFSAR. As noted in UFSAR Section 5.4.2, the WBN Unit 1 RPV is cylindrical with a welded hemispherical bottom head and a removable, bolted, flanged, and gasketed hemispherical upper head.

The RPV flange and head are sealed by two hollow metallic o-rings. Seal leakage is detected by means of two leakoff communications (i.e., one between the inner and outer ring and one outside the outer o-ring. The RPV contains the core, core support structures, control rods, and other parts directly associated with the core.

The RPV was designed and fabricated in accordance with the requirements of Section III, Class 1, of the ASME Code edition, addenda, and Code Cases applicable at the time of plant design and construction. Operating limitations of the ASME Code and of 10 CFR Part 50, Appendix G, "Fracture Toughness Requirements," also apply. The RPV and the reactor coolant system (RCS) were designed to allow inspections in accordance with Section XI of the ASME Code. Industry experience with steel structures confirms a service life in excess of 40 years.

Over the operating life of a reactor vessel, ferritic materials exposed to neutron irradiation will undergo changes in material properties and a decrease in fracture toughness. The decrease in fracture toughness is of importance because the ability of ferritic materials to resist failure caused by the propagation of a crack decreases with increasing irradiation. A surveillance program in accordance with 10 CFR Part 50, Appendix H, "Reactor Vessel Materials Surveillance Program Requirements," was developed to monitor the fracture toughness of the RPV. The purpose of the program is to help ensure RPV integrity by monitoring changes in the fracture toughness properties of the RPV beltline materials. Input from this program is used to develop operating limits, in the form of pressure/temperature (P/T) limit curves, which ensure adequate margin with regard to brittle failure of the RPV and piping of the reactor coolant pressure boundary.

The WBN Unit 1 PTLR is described in WBN Unit 1 TS 5.9.6, Reactor Coolant System (RCS) PRESSURE AND TEMPERATURE LIMITS REPORT (PTLR), and is contained in Appendix A to TVA procedure SDD-N3-68-4001, REACTOR COOLANT SYSTEM Unit 1 /

Unit 2 QA Record. The PTLR contains the RCS heatup and cooldown curves and a schedule for removal of reactor vessel surveillance capsules, which has been reviewed and approved by the NRC in Reference 4.

As noted in WCAP-18769-NP, Revision 1, Watts Bar Units 1 & 2 Reactor Vessel Integrity Evaluations for the 2496 TPBAR Implementation Project, which was submitted to NRC in Reference 5 and reviewed by the NRC in Reference 6, The upper-shelf energy (USE) values of all of the beltline and extended beltline materials in the WBN Unit 1 reactor pressure vessel are projected to remain above the USE screening criterion of 50 ft-lb (per 10 CFR 50 Appendix G Section IV.A.1), through end-of-license (32 EFPY) and end-of-license-extension (48 EFPY) with one exception. The WBN Unit 1 intermediate shell forging 05 has a USE value below the 50 ft-lb screening criterion for the end-of-license and end-of-license-extension. However, as previously outlined in WCAP-16760-NP, the USE remains above the 43 ft-lb lower bound as determined in the generic evaluation, WCAP-13587, Revision 1.

The P/T limits of 10 CFR 50 Appendix G are addressed in the plant TS and are specified in the PTLR. As previously noted, the current P/T limits are based on an assumed RPV exposure of 32 EFPY, which will be exceeded prior to the end of the current FPOL, even without the proposed 90-day license recapture period. The WBN Unit 1 P/T limits will therefore be updated and documented in the PTLR prior to the reactor achieving an actual exposure of

Enclosure CNL-24-010 E-5 of 12 32 EFPY, and will bound the 40-year FPOL period, including the proposed 90-day license recapture period. The reference temperature for pressurized thermal shock (RTPTS) values of the beltline and extended beltline materials in the WBN Unit 1 RPV are below the RTPTS screening criteria of 270°F for the base metal and/or longitudinal welds, and 300°F for circumferentially oriented welds (per 10 CFR 50.61.b.2) through the current end-of-license and the proposed 90-day license recapture period.

The above conclusions regarding material acceptability through 2036 are based on updated analyses of vessel fluence which were submitted to NRC in Reference 5 and reviewed by the NRC in Reference 6. The updated analyses in Reference 5 account for the effects of ultra-low-leakage core designs that have been in use since WBN Unit 1 Cycle 2 and will continue to be used for the remainder of plant life.

The reactor vessel was initially designed and licensed based on a 40-year service life with an 80 percent (%) capacity factor. A comprehensive vessel material surveillance program is maintained in accordance with 10 CFR 50, Appendix H. The first surveillance capsule for WBN Unit 1 was pulled at the end of the first fuel cycle, which corresponds to 1.20 EFPY (Reference 7). The second capsule taken out of WBN Unit 1 was after the third fuel cycle at 3.88 EFPY (Reference 8) and represented the combined results of the standard and low leakage core design. The third capsule was taken out of WBN Unit 1 after the fifth fuel cycle at 6.63 EFPY (Reference 9). The fourth capsule was taken out of WBN Unit 1 after the seventh fuel cycle at 9.37 EFPY (Reference 10). In accordance with the RPV integrity analysis in WCAP-18769-NP (Reference 5), the WBN Unit 1 limiting RTPTS value for base metal or longitudinal weld materials is 235.9°F at 48 EFPY, which corresponds to the Intermediate Shell Forging 05. The limiting RTPTS value for circumferentially oriented welds is 57.2°F at 48 EFPY, which corresponds to the lower shell to bottom head ring circumferential weld seam W04. The RTPTS value for WBN Unit 1 would be 34.1°F less than the 10 CFR 50.61 screening criterion of 270°F for plates, forgings, and longitudinal welds and 242.8°F less than the screening criteria for circumferentially oriented welds. Therefore, the PTS screening criteria would not be exceeded.

Based on the above discussion, there is reasonable assurance that the WBN Unit 1 RPV will continue to meet applicable 10 CFR Part 50 and WBN Unit 1 license requirements during the additional 90 days of plant operation sought by this low-power testing recapture request.

3.2 Structures WBN Unit 1 was designed to meet the intent of the "Proposed General Design Criteria for Nuclear Power Plant Construction Permits" published in July 1967. The WBN construction permit was issued in January 1973. The WBN dual-unit UFSAR, however, addresses the NRC General Design Criteria (GDC) published as Appendix A to 10 CFR 50 in July 1971, including Criterion 4 as amended October 27, 1987. Compliance with the GDC is discussed in Section 3.1 of the WBN dual-unit UFSAR.

As noted in Section 3.1 of the WBN dual-unit UFSAR, the reactor containment (UFSAR Section 6.2) is a freestanding, continuous steel membrane structure housing the reactor and various auxiliary components including the ice condenser. The ice condenser (UFSAR Section 6.7) limits the initial containment pressure to a value less than design during a large loss of coolant accident (LOCA). A concrete Shield Building surrounding the steel vessel allows for collection of any containment leakage, which is subsequently processed by the emergency gas treatment system before release to the environment. The containment also

Enclosure CNL-24-010 E-6 of 12 contains a spray system which supplements the ice condenser in limiting pressure and which also provides long-term cooling following a LOCA. The design pressure is not exceeded in any pressure transients which result from combining the effects of heat sources with minimal operation of the engineered safety features.

As noted in Section 3.8 of the dual-unit UFSAR, the WBN Unit 1 Shield Building is a reinforced concrete structure surrounding the steel containment structure and is designed to provide radiation shielding from accident conditions, radiation shielding from parts of the RCS during operation, and protection of the steel containment vessel from adverse atmospheric conditions and external missiles propelled by tornado winds. The Shield Building is a reinforced concrete cylinder supported by a circular base slab and covered at the top with a spherical dome. The Shield Building is a Category I structure in its entirety and is designed to remain functional in the event of a Safe Shutdown Earthquake (SSE) or a tornado.

The NRC reviewed the WBN Unit 1 design basis, fabrication, construction, and implementation of quality assurance (QA) criteria when the plant was licensed for low-power operation. The NRC's safety evaluations approving the programs and their implementation with respect to these structures are documented in the NRC's Safety Evaluation Report for WBN (NUREG-0847) and its 29 supplements. Industry experience with concrete and steel structures confirms a service life in excess of 40 years. The license recapture period requested by the proposed amendment represents less than 0.7% of the 40-year service life of the plant.

The structural design of the reinforced concrete Shield Building is in compliance with the American Concrete Institute (ACI)-ASME (ACI-359) Code for Concrete Reactor Vessels and Containment, Article CC-3000, for the loading combinations defined in Table 3.8.1-1.

Allowable stresses are based on this code with the exception of allowable tangential shear stresses in walls where the ACI 318-71 code is used. Detailing of reinforcing around opening of circular walls is based on the ACI Chimney Code (ACI 307-69), Sections 4.4.4 through 4.4.7. The reinforcing steel conforms to the requirements of ASTM Designation A615-72, Grade 60. Structural design of the interior concrete structures is in compliance with the ACI 318-71 Building Code Requirements for Reinforced Concrete, and ACI-ASME (ACI 359) Article CC 3000 document, "Standard Code for Concrete Reactor Vessels and Containments."

Section 3.8.1 of NUREG-0847 states that the criteria that were used in the analysis, design, and construction of seismic Category 1 structures at WBN Unit 1 account for anticipated loading and postulated conditions that may be imposed on the structures during their service lifetime, which would encompass the requested 90 days of additional power operation within the requested license recapture period.

As noted above, the NRC has approved TVA's use of the above referenced codes, standards, and specifications in the WBN Unit 1 design, analyses, and construction, as well as the TVA QA program required by 10 CFR Part 50, Appendix B, "Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants." Thus, there is reasonable assurance that the concrete and steel structures will continue to comply with applicable NRC regulations and WBN Unit 1 operating license requirements during the proposed 90-day license term extension.

Enclosure CNL-24-010 E-7 of 12 3.3 Mechanical Equipment Surveillance, maintenance, and testing requirements for mechanical equipment are in place to verify operability or to detect degradation and ensure that the equipment that does degrade is replaced or other corrective actions are taken. In addition, sub-components such as nonmetallics (e.g., gaskets and o-rings) are inspected and replaced as necessary, as part of routine maintenance to ensure the design life of equipment. Surveillance, inspection, and testing requirements at WBN Unit 1, which apply during the plant's operating life, including the following.

ASME Code Section XI: Equipment that is safety-related is ASME Code Class 1, 2, or 3 and is subject to the inservice inspection requirements of Section XI and 10 CFR 50.55a, except where the NRC has granted written relief from these requirements. These requirements apply throughout the operating life of a plant and provide reasonable assurance that mechanical components will be properly monitored throughout the plant lifetime.

10 CFR 50.36 requires the establishment of limiting conditions for operation (LCOs) for certain equipment. LCOs are the lowest functional capability or performance levels of equipment required for safe operation of the facility. This equipment is subject to the surveillance and testing requirements in the TS to assure systems are operable. These surveillance requirements include calibration and inspection of systems and components to ensure that operation of the plant will remain in accordance with the LCOs.

10 CFR Part 50, Appendix J: Equipment and components associated with containment penetrations, including containment isolation valves, are subject to the leak testing requirements in 10 CFR Part 50, Appendix J, Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors. This is for Type B and C testing of valves and penetrations, and Type A testing of the overall containment structure. These tests verify the integrity of the containment and associated components and confirm that the containment and associated components are capable of performing their designed safety function as assumed in the accident analyses for WBN Unit 1.

Mechanical equipment that is required to perform a design safety function is designed to accommodate the effects of, and to be compatible with, the environmental conditions associated with normal operation, maintenance, testing, and postulated accidents, including loss-of-coolant accidents in accordance with GDC 4.

TVA concludes that compliance with the codes, standards, and regulatory requirements to which the mechanical equipment was analyzed, constructed, tested, and inspected provide reasonable assurance that the structural integrity of equipment important to safety will be maintained during the operating life of the plant, including the additional 90 days of operating life requested in this amendment. Such compliance further ensures that any significant degradation of mechanical equipment is discovered and the equipment is restored to an acceptable and operable condition.

3.4 Electrical Equipment Aging analysis has been performed for all safety-related electrical equipment in accordance with 10 CFR 50.49, "Environmental qualification of electric equipment important to safety for nuclear power plants", and has identified qualified lifetimes for this equipment. These lifetimes have been incorporated into plant equipment maintenance and replacement practices to ensure that

Enclosure CNL-24-010 E-8 of 12 all electrical equipment important to safety remains qualified and available to perform its safety function regardless of the overall age of the plant. If a component has a qualified life of less than 40 years, then its replacement is scheduled through the maintenance program. Therefore, the environmental qualification program supports the proposed amendment.

3.5 Quality Assurance and Maintenance Programs In licensing WBN Unit 1, the NRC reviewed the QA program and the conduct of operations, including the maintenance procedures. The QA program for plant operations assesses how the plant organization is following procedures and meeting requirements for plant operation.

This includes the plant maintenance program that assures the equipment is operable. In NUREG-0847, the NRC concluded that the QA program and maintenance procedures were acceptable.

NRC inspections of the QA and maintenance programs at WBN Unit 1 since the plant was licensed show that these programs remain acceptable. The QA program meets the requirements of 10 CFR Part 50, Appendix B.

Therefore, TVA's implementation and use of the QA and maintenance programs at WBN Unit 1 provide reasonable assurance that, for the proposed license term extension, equipment important to safety will satisfy applicable NRC requirements and the WBN Unit 1 operating license.

3.6 Conclusion Based on the above discussion, TVA concludes that there are no safety issues that would preclude an additional 90 days of operation beyond the current FPOL expiration date. This time period is insignificant from an aging effects perspective, particularly when considered in conjunction with the surveillance, inspection, quality assurance, and maintenance programs implemented to provide early indication of degradation in plant safety-related equipment. Ongoing maintenance and testing provide for continued safe operation of the unit throughout the duration of the facility operating license, and would continue to do so during the additional 90 days of operation requested by this proposed amendment.

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements and Criteria The following regulations apply to the proposed license amendment.

10 CFR 51.22, "Criterion for categorical exclusion; identification of licensing and regulatory actions eligible for categorical exclusion or otherwise not requiring environmental review."

10 CFR 50.90, "Application for amendment of license or construction permit."

10 CFR 50.92, "Issuance of amendment" The following NRC documents are relevant to the proposed amendment.

SECY-98-296, "Agency Policy Regarding Licensee Recapture of Low-Power Testing or Shutdown Time for Nuclear Power Plants," (Reference 11).

Enclosure CNL-24-010 E-9 of 12 SRM Regarding SECY-98-296, "Staff Requirements - SECY-98-296 - Agency Policy Regarding Licensee Recapture of Low-Power Testing or Shutdown Time for Nuclear Power Plants," (Reference 3).

In Reference 3, the Commission established NRC policy regarding recapture of low-power testing time for nuclear power plants. Specifically, the Commission approved the NRC staff's plan to grant a licensee request to amend the Grand Gulf Nuclear Station (GGNS)

FPOL to extend the license expiration date to recover time spent in low-power testing before FPOL issuance. The Commission also approved the practice of granting similar license amendment requests to amend the expiration dates of certain licenses to recover time spent in low-power testing before FPOL issuance. The proposed LAR falls within the scope of that policy.

The proposed amendment involves no physical changes to the design features or operation of the facility. The proposed amendment will not impact the design functions, or methods of performing or controlling design functions of structures, systems, and components. The proposed amendment will not affect the conduct of WBN Unit 1 programs. As a result, the proposed amendment will not change accident analysis assumptions, or change, degrade, or prevent actions described or assumed in accidents evaluated and described in the WBN dual-unit UFSAR. Therefore, the proposed amendment does not adversely affect public health and safety or result in an increase in the radiological consequences of any accident described in the WBN dual-unit UFSAR.

4.2 Precedent Consistent with the policy established by the NRC in References 3 and 11, the NRC has approved numerous requests to amend the expiration dates of reactor operating licenses issued under AEA Section 103.c to allow recapture of the time spent by the plants in low-power testing before issuance of their FPOLs (e.g., References 12 through 20).

4.3 No Significant Hazards Consideration Analysis In accordance with the provisions of Title 10 of the Code of Federal Regulations (10 CFR) 50.90, "Application for amendment of license, construction permit, or early site permit,"

Tennessee Valley Authority (TVA) is submitting a request for an amendment to Facility Operating License No. NPF 90 for the Watts Bar Nuclear Plant (WBN), Unit 1.

The proposed amendment would revise the expiration date of the WBN Unit 1 operating license (OL) to recapture low-power testing time. Specifically, the full-power operating license (FPOL) for WBN Unit 1 would be amended to reflect an expiration date that is 40 years from the date of issuance of the FPOL, as opposed to 40 years from the date of issuance of the low power operating license (LPOL), as permitted by 10 CFR 50.51.

Specifically, the FPOL would be extended by 90 days and would expire on February 7, 2036, instead of November 9, 2035.

TVA evaluated whether or not a significant hazards consideration is involved with the proposed amendments by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of Amendment," as discussed below.

Enclosure CNL-24-010 E-10 of 12

1. Does the proposed amendment involve a significant increase in the probability or consequence of an accident previously evaluated?

Response: No.

The proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated because it does not involve a change to the design configuration or operation of the facility. The proposed change does not affect the source term, containment isolation, or radiological release assumptions used in evaluating the radiological consequences of an accident previously analyzed in the WBN dual-unit Updated Final Safety Analysis Report (UFSAR).

WBN Unit 1 was designed and constructed to ensure at least a 40-year service life.

Design features provide for inspection of structures, systems, and components during this service life. Surveillance, inspection, and maintenance practices which have been implemented in accordance with the American Society of Mechanical Engineers Boiler and Pressure Vessel Code and the WBN Unit 1 Technical Specifications (TS), provide assurance that any degradation in plant safety-related equipment will be identified and corrected to ensure continued safe operation of the unit throughout the duration of the facility operating license.

The low-power testing recapture period requested by this amendment is for 90 days.

This time period is insignificant from an aging effects perspective, particularly when considered in conjunction with the surveillance, inspection, and maintenance programs described above.

Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

The proposed amendment would revise the expiration date of the facility OL to base it upon the issuance date of the FPOL and not the issuance date of the LPOL. The proposed change does not involve physical alteration of plant systems, structures, or components, or changes in parameters governing the manner in which the plant is operated and maintained.

Therefore, the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.

3. Does the proposed amendment involve a significant reduction in a margin of safety?

Response: No.

The proposed amendment would revise the expiration date of the facility OL to base it upon the issuance date of the FPOL and not the issuance date of the LPOL. No physical changes are being made to the design features or operation of the facility.

Margin of safety is associated with confidence in the ability of the fission product barriers (i.e., fuel cladding, reactor coolant system pressure boundary, and containment

Enclosure CNL-24-010 E-11 of 12 structure) to limit the radiological dose to the public and control room operators in the event of an accident. The proposed amendment to the facility OL has no impact on the margin of safety and robustness provided in the design and construction of the facility.

In addition, the proposed amendment will not relax any of the criteria used to establish safety limits, nor will the proposed amendment relax safety system settings or limiting conditions for operation as defined in the TS.

Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Based on the above, it is concluded that the proposed amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of no significant hazards consideration is justified.

4.4 Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement.

However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any radioactive effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

6.0 REFERENCES

1. NRC letter to TVA, Issuance of Facility Operating License No. NPF-20, Watts Bar Nuclear Plant, Unit 1 (TAC M91489), dated November 9, 1995 (ML020780254)

2. NRC letter to TVA, Issuance of Facility Operating License No. NPF-90, Watts Bar Nuclear Plant, Unit 1 (TAC M94025), dated February 7, 1996 (ML080290360)

3. SRM Regarding SECY-98-296, "Staff Requirements - SECY-98-296 - Agency Policy Regarding Licensee Recapture of Low-Power Testing or Shutdown Time for Nuclear Power Plants," dated March 30, 1999 (ML20205C095)

4. NRC letter to TVA, Watts Bar Nuclear Plant, Unit 2 - Revision to the Reactor Vessel Material Surveillance Capsule Withdrawal Schedule (EPID L-2022-LLL-0000), dated November 14, 2022 (ML22293A408)

5. TVA Letter to NRC, CNL-23-002, Application to Revise Watts Bar Nuclear Plant Units 1 and 2 Technical Specifications to Change the Number of Tritium Producing Burnable Absorber Rods (WBN-TS-21-02) and Proposed Revision to Reactor Vessel Surveillance Capsule Removal Schedule for Units 1 and 2, dated March 20, 2023 (ML23079A270)

Enclosure CNL-24-010 E-12 of 12

6. NRC letter to TVA, Watts Bar Nuclear Plant, Units 1 and 2 - Revision to the Reactor Vessel Material Surveillance Capsule Withdrawal Schedule (EPID L-2023-LLA-0039),

dated January 18, 2024 (ML24008A246)

7. WCAP-15046, Revision 0, Analysis of Capsule U From the Tennessee Valley Authority Watts Bar Unit 1 Reactor Vessel Radiation Surveillance Program, June 1998 (ML073240615)

8. BWXT Services, Inc., Analysis of Capsule W from the Tennessee Valley Authority Watts Bar Unit 1 Reactor Vessel Material Surveillance Program, September 2001 (ML012900048 and ML013060166)

9. TVA letter to NRC, Watts Bar Nuclear Plant (WBN) Unit 1 -- Reactor Vessel Surveillance Capsule X Test Results and Reactor Vessel Fracture Toughness (J-R) Test Results, dated October 20, 2004 (ML043000348)

10. WCAP-16760-NP, Revision 0, Analysis of Capsule Z from the Tennessee Valley Authority, Watts Bar Unit 1 Reactor Vessel Radiation Surveillance Program, November 2007 (ML073200241)

11. SECY-98-296, "Agency Policy Regarding Licensee Recapture of Low-Power Testing or Shutdown Time for Nuclear Power Plants," dated December 21, 1998 (ML992870025)

12. NRC letter to Palisades Plant, Palisades Plant - Issuance of Amendment Re: Revision to Operating License Expiration Date (TAC No. MA8753), dated December 14, 2000 (ML003777442)

13. NRC letter to Energy Harbor Nuclear Corp., Perry Nuclear Power Plant, Unit No. 1 -

Issuance of License Amendment No. 191 Regarding Recapture of Low-Power Testing Time (EPID L-2020-LLA-0053), dated October 8, 2020 (ML20216A354)

14. NRC letter to Pacific Gas and Electric Company, Diablo Canyon Power Plant, Unit Nos. 1 and 2 - Issuance of Amendments Re: Request for Recovery of Low-Power Testing Time - Impact on the Reactor Vessel Integrity Assessment (TAC Nos. MC8206 and MC8207), dated July 17, 2006 (ML061660220)

15. NRC letter to FPL Energy Seabrook, LLC, Seabrook Station, Unit No. 1 - Issuance of Amendment Re: Recapture of Zero-Power and Low-Power Testing Time (TAC No. MC6548), dated December 28, 2005 (ML052210002)

16. NRC letter to Arizona Public Service Company, Palo Verde Nuclear Generating Station, Units 1, 2, and 3 - Issuance of Amendments Re: Recapture Low-Power Testing Time (TAC Nos. MB6261, MB6262, MB6263), dated July 15, 2003 (ML031990086)

17. NRC letter to Commonwealth Edison Company, Dresden - Issuance of Amendment (TAC No. MA5414), dated August 24, 2000 (ML003744786)

18. NRC letter to Southern California Edison Company, San Onofre Nuclear Generating Station, Units 2 and 3 - Issuance of Amendments Re: Extend License Expiration Date (TAC Nos. MA7348 and MA7349), dated March 9, 2000 (ML003690021)

19. NRC letter to Exelon Generation Company, LLC, Clinton Power Station Unit No. 1 Issuance of Amendment Regarding Recapture of Low-Power Testing Time (EPID L-2018-LLA-0250), dated June 12, 2019 (ML19109A001)

20. NRC letter to Entergy Operations, Inc., Grand Gulf Nuclear Station, Unit 1 - Issuance of Amendment Re: Extension of Expiration Date of Operating License (TAC No. M92993),

dated April 26, 1999 (ML021490195)

Enclosure CNL-24-010 Proposed Change to Operating License (Mark-Up) for WBN Unit 1

6 I.

This license is effective as of the date of issuance and shall expire at midnight on November 9, 2035. February 7, 2036.

FOR THE NUCLEAR REGULATORY COMMISSION William T. Russell, Director Office of Nuclear Reactor Regulation Appendices:

1. Appendix A -

Technical Specifications

2. Appendix B -

Environmental Protection Plan Date of Issuance: February 7, 1996