CNL-23-043, Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, Modes (WBN-TS-23-09)

Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, Modes (WBN-TS-23-09)

ML23124A403
Person / Time
Site:	Watts Bar
Issue date:	05/04/2023
From:	Hulvey K Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation, Document Control Desk
Shared Package
ML23124A402	List: CNL-23-043, Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, Modes (WBN-TS-23-09)
References
CNL-23-043
Download: ML23124A403 (1)

Text

Proprietary Information - Withhold Under 10 CFR § 2.390 This letter is decontrolled when separated from Enclosure 2 1101 Market Street, Chattanooga, Tennessee 37402 CNL-23-043 May 4, 2023 10 CFR 50.90 10 CFR 50.91 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 0001 Watts Bar Nuclear Plant, Unit 1 Facility Operating License No. NPF-90 NRC Docket Nos. 50-390

Subject:

Watts Bar Nuclear Plant, Unit 1 - Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, MODES (WBN-TS-23-09)

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, and 10 CFR 50.91, Notice for public comment; State consultation, Tennessee Valley Authority (TVA) is submitting a request for a one-time amendment to Facility Operating License No. NPF-90 for the Watts Bar Nuclear Plant (WBN), Unit 1. The proposed change is being requested on an emergency basis pursuant to 10 CFR 50.91(a)(5).

This proposed emergency license amendment request (LAR) revises WBN Unit 1 Technical Specification (TS) Table 1.1-1, MODES, footnotes (b) and (c), to allow completion of the current WBN Unit 1 Cycle 18 refueling outage (U1R18) and transition to Cycle 19 operation and the subsequent Unit 1 Cycle 19 refueling outage (fall 2024) with the required reactor pressure vessel head closure bolts studs fully tensioned. The required number of head closure bolts is at least 53 of 54 bolts (stud 34 has been removed from service). to this submittal provides a description and technical evaluation of the proposed change, a regulatory evaluation, and a discussion of environmental considerations. to Enclosure 1 provides the existing WBN Unit 1 TS page marked up to show the proposed change. Attachment 2 to Enclosure 1 provides the proposed WBN Unit 1 TS page retyped to show the change incorporated. There are no associated TS Bases pages for this request.

Proprietary Information - Withhold Under 10 CFR § 2.390 This letter is decontrolled when separated from Enclosure 2

Proprietary Information - Withhold Under 10 CFR § 2.390 This letter is decontrolled when separated from Enclosure 2 U.S. Nuclear Regulatory Commission CNL-23-043 Page 2 May 4, 2023 TVA is requesting approval of the proposed amendment on an emergency basis pursuant to 10 CFR 50.91(a)(5) and is requesting approval by 0700 Eastern Daylight Time (EDT) on May 6, 2023, in order to support the currently planned startup from U1R18. WBN Unit 1 is currently in Mode 6 and will not transition to Mode 5 until this emergency license amendment request is approved. Therefore, Nuclear Regulatory Commission (NRC) approval of this LAR is needed on an emergency basis so as not to adversely impact the current outage schedule and startup for WBN Unit 1 Cycle 19. An explanation of the emergency and why it could not be avoided is included in Enclosure 1.

In support of the technical evaluation in Enclosure 1, Enclosure 2 contains Westinghouse Electric Company LLC (Westinghouse) WCAP-18774-P, Revision 1, Addendum to the Rotterdam Dockyard Company Final Stress Report for 173" P.W.R. Vessels TVA III & IV (Report No. 30749-B-030, Rev. 3) - Evaluation of One Closure Stud Out of Service for 40 Years for Watts Bar Units 1 and 2. Enclosure 2 contains information that Westinghouse considers to be proprietary in nature pursuant to 10 CFR 2.390, "Public inspections, exemptions, requests for withholding," paragraph (a)(4). Due to the emergent nature of this proposed amendment, Enclosure 2 is submitted as a proprietary document in its entirety.

TVA will submit a revision of Enclosure 2 with revised proprietary markings and an associated non-proprietary version within 30 days following NRC approval of this amendment request. provides the Westinghouse Application for Withholding Proprietary Information from Public Disclosure CAW-23-017 affidavit supporting this proprietary withholding request.

The affidavit sets forth the basis on which the information may be withheld from public disclosure by the NRC and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.390. Accordingly, TVA requests that the information, which is proprietary to Westinghouse, be withheld from public disclosure in accordance with 10 CFR 2.390. Correspondence with respect to the copyright or proprietary aspects of the items listed above or the supporting Westinghouse affidavit should reference CAW-23-017 and should be addressed to Camille T. Zozula, Manager, Regulatory Compliance &

Corporate Licensing.

TVA has determined that there are no significant hazards considerations associated with the proposed change and that the TS 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.

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

Proprietary Information - Withhold Under 10 CFR § 2.390 This letter is decontrolled when separated from Enclosure 2

Proprietary Information - Withhold Under 10 CFR § 2.390 This letter is decontrolled when separated from Enclosure 2 U.S. Nuclear Regulatory Commission CNL-23-043 Page 3 May 4, 2023 I declare under penalty of perjury that the foregoing is true and correct. Executed on this 4th day of May 2023.

Respectfully, Digitally signed by Edmondson, Carla Date: 2023.05.04 20:06:42 -04'00' Kimberly D. Hulvey Director, Nuclear Regulatory Affairs

Enclosures:

1. Evaluation of Proposed Change

2. WCAP-18774-P, Revision 1 (Proprietary)

3. Westinghouse Electric Company LLC Application for Withholding Proprietary Information from Public Disclosure (Affidavit CAW-23-017) cc (Enclosures):

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 Proprietary Information - Withhold Under 10 CFR § 2.390 This letter is decontrolled when separated from Enclosure 2

Enclosure 1 Evaluation of the Proposed Change

Subject:

Watts Bar Nuclear Plant, Unit 1 - Emergency License Amendment Request to Relax the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs in Technical Specification Table 1.1-1, MODES (WBN-TS-23-09)

CONTENTS 1.0

SUMMARY

DESCRIPTION ............................................................................................... 1 2.0 DETAILED DESCRIPTION ................................................................................................ 1 2.1 System Design and Operation ........................................................................................ 1 2.2 Circumstances Establishing Need for the Proposed Emergency Amendment ............... 2 2.3 Description of the Proposed Change .............................................................................. 4

3.0 TECHNICAL EVALUATION

............................................................................................... 5

4.0 REGULATORY EVALUATION

........................................................................................... 5 4.1 Applicable Regulatory Requirements and Criteria .......................................................... 5 4.2 Precedent ....................................................................................................................... 6 4.3 No Significant Hazards Consideration ............................................................................ 6 4.4 Conclusion ...................................................................................................................... 8

5.0 ENVIRONMENTAL CONSIDERATION

............................................................................. 8 Attachments:

1. Proposed TS Change (Markup) for WBN Unit 1

2. Proposed TS Change (Final Typed) for WBN Unit 1 CNL-23-043

Enclosure 1 Evaluation of the Proposed Change 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, and 10 CFR 50.91, Notice for public comment; State consultation, Tennessee Valley Authority (TVA) is submitting a request for a one-time amendment to Facility Operating License No. NPF-90 for the Watts Bar Nuclear Plant (WBN), Unit 1. The proposed change is being requested on an emergency basis pursuant to 10 CFR 50.91(a)(5).

This proposed emergency license amendment request (LAR) revises WBN Unit 1 Technical Specification (TS) Table 1.1-1, MODES, footnotes (b) and (c), to allow completion of the current WBN Unit 1 Cycle 18 refueling outage (U1R18), through Cycle 19, and prior to Cycle 20 operation, with 53 of 54 Reactor vessel head closure bolts fully tensioned due to stud #34 being removed, as described in Section 2.3 to this enclosure. This one-time amendment change will apply for operation of WBN Unit 1 for Cycle 19, including any emergent unit shutdowns and restarts. This one-time allowance will end following the Unit 1 Cycle 19 refueling outage prior to Cycle 20 operation at which time either a permanent amendment change will be required or stud #34 has been reinstalled and fully tensioned to permit Cycle 20 operation.

TVA is requesting approval of the proposed amendment on an emergency basis pursuant to 10 CFR 50.91(a)(5). WBN Unit 1 is currently in Mode 6 and will not transition to Mode 5 until this emergency license amendment request is approved. Therefore, NRC approval of this LAR is needed on an emergency basis so as not to adversely impact the current outage schedule and startup for WBN Unit 1 Cycle 19. An explanation of the emergency and why it could not be avoided is provided in Section 2.2 to this enclosure.

2.0 DETAILED DESCRIPTION 2.1 System Design and Operation The WBN Unit 1 reactor vessel was designed and fabricated in accordance with the requirements of American Society of Mechanical Engineers (ASME)Section III 1971 Edition through Winter 1971 Addenda with the following addition:

Closure studs, nuts, washers, inserts, and adaptors in accordance with SA-540 class 3 Gr. B-24 as modified by Code Case 1605.

The reactor pressure vessel is American Nuclear Society (ANS) Safety Class 1 and the pressure boundary meets the requirements of the ASME Boiler and Pressure Vessel Code,Section III, Subsection NB. This equipment is evaluated for the loading combinations outlined in Table 5.2-4 of the Updated Final Safety Analysis Report (UFSAR). The equipment is analyzed for (1) the normal loads of deadweight, pressure, and thermal, (2) mechanical transients of operating basis earthquake, safe shutdown earthquake, and pipe ruptures, and (3) pressure and temperature transients outlined in WBN UFSAR Section 5.2.1.5. The reactor pressure vessel is described in WBN UFSAR Section 5.4.2.

The reactor vessel is cylindrical with a welded hemispherical bottom head and a removable, bolted, flanged, and gasketed, hemispherical upper head. The reactor vessel flange and head are sealed by two metallic O-rings and are secured by the reactor vessel head closure studs.

CNL-23-043 E1-1 of 8

Enclosure 1 There are a total of 54 locations for the studs to be installed around the circumference of the reactor vessel head. To ensure full engagement of the O-rings, a minimum of 53 of the 54 studs are required to be fully tensioned. The nuts on the studs are tightened with a stud tensioner.

Seal leakage is detected by means of two leakoff communications: one between the inner and outer reactor vessel flange O-rings and one outside the outer reactor vessel flange O-ring. The temperature in the leakoff line from the reactor vessel flange O-ring seal leakage monitor connections is indicated. An increase in temperature above ambient is an indication of O-ring seal leakage. High temperature actuates an alarm in the Main Control Room. The reactor vessel head flange leakage detection is described in WBN UFSAR Sections 5.4.2 and 5.4.6 which provide assurance that leakage would be collected and analyzed in the event of untensioned stud leakage. Additionally, the WBN reactor coolant leakage detection system (see WBN Unit 1 TS 3.4.13, RCS Operational LEAKAGE) conforms to the guidance in Regulatory Guide 1.45, "Reactor Coolant Pressure Boundary Leakage Detection Systems."

As required by ASME Code Section XI, a leakage test is performed on the primary side following reactor reassembly each refueling outage. During this test, the pressure is raised to 2280 pounds per square gauge (psig) with the system temperature above the minimum temperature imposed by reactor vessel material ductility requirements while the system is checked for leaks.

TVA procedures provide the methodology for tensioning the reactor pressure vessel closure studs. Three tensioners are provided and are applied simultaneously to three studs located 120 degrees apart. A single hydraulic pumping unit operates the tensioners, which are hydraulically connected. The studs are tensioned to their operational load in two steps to prevent high stresses in the flange region and unequal loadings in the studs.

2.2 Circumstances Establishing Need for the Proposed Emergency Amendment Regulation 10 CFR 50.91, "Notice for public comment; State consultation," paragraph (a)(5) states that where the NRC finds that an emergency situation exists, in that failure to act in a timely way would result in the derate or shutdown of a nuclear power plant, it may issue a license amendment involving no significant hazards consideration without prior notice and opportunity for a hearing or public comment. The regulation requires that a licensee requesting an emergency amendment explain why the emergency situation occurred and why the licensee could not avoid the situation.

During the Unit 1 Cycle 16 refueling outage (U1R16) in May 2020, when removing the reactor vessel studs after de-tensioning, difficulty was encountered while attempting to remove the reactor vessel closure stud at Location #34. The stud was eventually removed, but visual inspection of the stud determined there was damage to the lower portion of the threads. The stud threads were subsequently inspected, repaired, and cleaned. However, the threads in the

1. 34 stud hole were not inspected prior to the off load of the Unit 1 core.

During a typical refueling outage, the studs are removed from the cavity to ensure the studs do not come in contact with borated water. The stud holes are covered so that the holes are protected from the borated water when the cavity is flooded up. During U1R16, because the stud holes were not inspected once stud #34 was found damaged, the stud holes could not be inspected until after the core was reloaded, the head placed back on the vessel, and the cavity drained. This meant that the threads at stud hole #34 could not be inspected until the end of the outage at which point it was determined that the threads were potentially damaged to the point CNL-23-043 E1-2 of 8

Enclosure 1 that significant planning, effort, and mobilization would be required to repair the stud hole.

Therefore, stud #34 was removed from service.

The review of the stud hole #34 non-conformance was evaluated under the provision of 10 CFR 50.59 and determined that a revision to WBN UFSAR Table 5.4-1, Reactor Vessel Design Parameters, could be made to reflect that only 53 of the 54 studs are required to be installed and tensioned and that this UFSAR revision did not require prior NRC approval. This evaluation also determined that a TS change was not required because TVA believed that the intent of the footnotes (b) and (c) to WBN Unit 1 TS Table 1.1-1 was still being satisfied and that no changes were needed to WBN Unit 1 TS 3.4.3 RCS Pressure and Temperature (P/T)

Limits and TS 3.4.12 Cold Overpressure Mitigation System (COMS), because the reactor vessel studs are not modeled in the supporting analyses. This evaluation was also supported by a Westinghouse analysis that concluded that functionality of 53 of the 54 studs is acceptable (see Enclosure 2).

During the U1R18 outage, while preparations were being made to transition from Mode 5 to Mode 4, the NRC challenged TVA compliance with footnotes (b) and (c) to WBN Unit 1 TS Table 1.1-1. Specifically, the NRC expressed that the term all in these footnotes applies to the originally licensed 54 reactor vessel head closure bolts in the WBN UFSAR and that operation with less than 54 bolts requires a change to the TS. Therefore, based on this more recent view of TS Table 1.1-1, TVA has concluded that a change to the Technical Specification definitions for Mode 4, Mode 5, and Mode 6 is appropriate to better define the meaning of all in Table 1.1-1 to reflect the current WBN 1 Unit configuration. Subsequently, on May 3, 2023, TVA transitioned WBN Unit 1 from Mode 5 back to Mode 6 pending the review and approval of this emergency LAR. This event has been entered into the sites corrective action program.

TVA has been operating under the basis that the 10 CFR 50.59 change was acceptable and that the UFSAR change did not require prior NRC approval nor a change to the TS. Therefore, TVA could not have reasonably anticipated the need for an emergency license amendment in advance of the event or in a more timely manner in order to restore TS compliance for continued operation of WBN Unit 1. Furthermore, as demonstrated in Section 4.3, the proposed change does not involve a significant hazards consideration.

Based on the above, the requirements for an emergency situation as stipulated in 10 CFR 50.91(a)(5) have been satisfied.

CNL-23-043 E1-3 of 8

Enclosure 1 2.3 Description of the Proposed Change The emergency LAR proposes the following change to WBN Unit 1 TS Table 1.1-1:

Table 1.1-1 (page 1 of 1)

MODES REACTIVITY AVERAGE

% RATED CONDITION REACTOR COOLANT MODE TITLE THERMAL (keff) TEMPERATURE POWER (a)

(F) 1 Power Operation 0.99 >5 NA 2 Startup 0.99 5 NA 3 Hot Standby < 0.99 NA 350 4 Hot Shutdown (b) < 0.99 NA 350 > Tavg > 200 5 Cold Shutdown (b) < 0.99 NA 200 6 Refueling (c) NA NA NA (a) Excluding decay heat.

(b) For transitioning from the Unit 1 Cycle 18 refueling outage, through Cycle 19, and prior to Cycle 20 operation, Aall required reactor vessel head closure bolts fully tensioned.

The required number of head closure bolts is at least 53 of 54 bolts (stud 34 has been removed from service).

(c) For transitioning from the Unit 1 Cycle 18 refueling outage, through Cycle 19, and prior to Cycle 20 operation, Oone or more required reactor vessel head closure bolts less than fully tensioned. The required number of head closure bolts is at least 53 of 54 bolts (stud 34 has been removed from service). to Enclosure 1 provides the existing WBN Unit 1 TS page marked up to show the proposed change. Attachment 2 to Enclosure 1 provides the proposed WBN Unit 1 TS page retyped to show the change incorporated. There are no associated TS Bases pages for this request.

As noted above, the proposed changes to WBN Unit 1 Table 1.1-1 are temporary to allow WBN Unit 1 to start-up from the U1R18 refueling outage, through Cycle 19, and prior to Cycle 20 operation, with 53 of 54 Reactor vessel head closure bolts fully tensioned due to stud #34 being removed. This one-time amendment change will apply for operation of WBN Unit 1 for Cycle 19, including any emergent unit shutdowns and restarts. This one-time allowance will end following Unit 1 Cycle 19 refueling outage prior to Cycle 20 operation at which time either a permanent amendment change will be required or stud #34 has been reinstalled and fully tensioned to permit Cycle 20 operation.

CNL-23-043 E1-4 of 8

Enclosure 1 Following NRC approval of this emergency LAR, TVA plans to submit a LAR to permanently change WBN Unit 1 Table 1.1--1 to allow continued operation with only the required reactor vessel head closure bolts fully tensioned in order to support future WBN Unit 1 operation.

3.0 TECHNICAL EVALUATION

contains Westinghouse Electric Company LLC (Westinghouse) WCAP-18774-P, Revision 1, Addendum to the Rotterdam Dockyard Company Final Stress Report for 173" P.W.R. Vessels TVA III & IV (Report No. 30749-B-030, Rev. 3) - Evaluation of One Closure Stud Out of Service for 40 Years for Watts Bar Units 1 and 2, which supports continued operation of WBN Unit 1 with 53 of 54 reactor vessel head closure bolts fully tensioned.

Section 5.1.4 of Enclosure 2 specifically addresses thread engagement.

As noted in Enclosure 2, the maximum stresses in the adjacent studs, the bearing stress in the closure head flange, and the sealing of the reactor vessel O-rings remain acceptable when one stud is left out of service during reactor operation. All of the stress intensities still satisfy the applicable limits of Section III of the 1971 Edition of the ASME Code with Addenda through Winter 1971, which is the construction Code used to design the Watts Bar Unit 1 and Unit 2 reactor vessels. The cumulative usage factor (CUF) less than 1.0 for the studs adjacent to the out-of-service stud permits the plant to operate for the remainder of the 40-year design life with one stud out of service to allow adequate time for contingencies regarding stud hole repair preparation and implementation.

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements and Criteria General Design Criteria (GDC)

WBN Units 1 and 2 were 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 updated Final Safety Analysis Report (UFSAR),

however, addresses the GDC published as Appendix A to 10 CFR 50 in July 1971.

Conformance with the GDCs is described in Section 3.1.2 of the UFSAR.

Each criterion listed below is followed by a discussion of the design features and procedures that meet the intent of the criteria. Any exception to the 1971 GDC resulting from the earlier commitments is identified in the discussion of the corresponding criterion.

Criterion 14 - Reactor Coolant Pressure Boundary. The reactor coolant pressure boundary shall be designed, fabricated, erected, and tested so as to have an extremely low probability of abnormal leakage or rapidly propagating failure and of gross rupture.

Criterion 30 - Quality of reactor coolant pressure boundary, Components which are part of the reactor coolant pressure boundary shall be designed, fabricated, erected, and tested to the highest quality standards practical. Means shall be provided for detecting and, to the extent practical, identifying the location of the source of reactor coolant leakage.

Compliance with GDCs 14 and 30 are described in Section 3.1.2 of the WBN UFSAR.

CNL-23-043 E1-5 of 8

Enclosure 1 With the implementation of the proposed changes, WBN Unit 1 continues to meet the applicable regulations and requirements, subject to the previously approved exceptions.

4.2 Precedent The proposed changes are similar to NRC-approved license amendment issued to:

Braidwood Station Units 1 and 2 and Byron Station Units 1 and 2 on October 28, 2015, in Amendment Nos. 186 and 192, respectively (ML15232A441). These amendments approved the use of the methodology for developing the pressure and temperature limits reports and changed TS Table 1.1-1, MODES, footnote (b) to state: All required reactor vessel head closure bolts fully tensioned and footnote (c) to state: One or more required reactor vessel head closure bolts less than fully tensioned (emphasis added). The proposed emergency license amendment request for WBN Unit 1 is not requesting changes to the pressure and temperature limits methodology.

Callaway Plant Unit 1 on May 28, 1999, in Amendment No. 133 (ML021640446).

Amendment No. 133 converted the current TSs to the improved TSs. The amendment approved changes to TS Table 1.1-1 based on an NRC Safety Evaluation issued on May 26, 1988 (ML20155J379 and ML20155J490) associated with the operation of the Callaway Plant with stud #2 untensioned. Amendment No. 133 revised footnote (b) to state:

At least 53 of 54 reactor vessel head closure bolts fully tensioned and footnote (c) to state:

Two or more reactor vessel head closure bolts less than fully tensioned.

The approved TS changes are similar to the changes proposed in this emergency LAR.

4.3 No Significant Hazards Consideration Tennessee Valley Authority (TVA) is requesting an emergency license amendment request (LAR) to Facility Operating License No. NPF-90 for Watts Bar Nuclear Plant (WBN) Unit 1. The proposed change is being requested on an emergency basis pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.91(a)(5).

This proposed emergency LAR revises WBN Unit 1 Technical Specification (TS) Table 1.1-1, MODES, footnotes (b) and (c), to allow completion of the current WBN Unit 1 Cycle 18 refueling outage (U1R18), through Cycle 19, and prior to Cycle 20 operation with the required reactor pressure vessel head closure studs fully tensioned (i.e., 53 of 54).

TVA is requesting approval of the proposed amendment on an emergency basis pursuant to 10 CFR 50.91(a)(5). The TS change will provide a one-time allowance that will be in effect until Mode 4 is entered from Mode 6 during the Unit 1 Cycle 19 refueling outage (fall 2024).

Westinghouse WCAP-18774-P, Revision 1, provides the technical evaluation in support of this proposed change.

TVA has 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:

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

Response: No CNL-23-043 E1-6 of 8

Enclosure 1 Overall protection system performance will remain within the bounds of the accident analyses because no hardware changes are proposed. Because the stresses remain within ASME Code allowables, the proposed change will not affect the probability of any event initiators. Nor will the proposed change affect the ability of any safety related equipment to perform its intended function. There will be no degradation in the performance of nor an increase in the number of challenges imposed on safety related equipment assumed to function during an accident situation.

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.

There are no hardware changes nor are there any changes in the method by which any safety related plant system performs its safety function. The method of plant operation is unaffected. Leakage would be precluded because adequate compression remains.

Analysis demonstrates that any gap opening remains less than the springback recovery of the inner closure O-ring. Because stresses remain within ASME Code allowables, no new accident scenarios, transient precursors, failure mechanisms, or limiting single failures are introduced as a result of this change.

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

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

Response: No.

The proposed change does not affect any safety limits or controlling numerical values for a parameter established in the updated final safety analysis report or any specific values that define margin that are established in the plants licensing basis. ASME Section III stress limits for affected components are not exceeded. Plant specific evaluations indicate that the reactor vessel will continue to meet ASME Code allowable stress criteria with the required reactor pressure vessel closure studs fully tensioned. The proposed change does not alter nor exceed the acceptance criteria for any analyzed event. There will be no effect on the manner in which safety limits or limiting safety system settings are determined nor will there be any effect on those plant systems necessary to assure the accomplishment of protection functions.

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

Based on the above, TVA concludes 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.

CNL-23-043 E1-7 of 8

Enclosure 1 4.4 Conclusion 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 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.

CNL-23-043 E1-8 of 8

Enclosure 1 Attachment 1 Proposed TS Changes (Mark-Ups) for WBN Unit 1 CNL-23-043

Definitions 1.1 Table 1.1-1 (page 1 of 1)

MODES

% RATED AVERAGE REACTIVITY THERMAL REACTOR COOLANT MODE TITLE CONDITION POWER (a) TEMPERATURE (keff) (°F) 1 Power Operation 0.99 >5 NA 2 Startup 0.99 <5 NA 3 Hot Standby < 0.99 NA 350 4 Hot Shutdown (b) < 0.99 NA 350 > Tavg > 200 5 Cold Shutdown (b) < 0.99 NA < 200 6 Refueling (c) NA NA NA (a) Excluding decay heat.

(b) For transitioning from the Unit 1 Cycle 18 refueling outage, through Cycle 19, and prior to Cycle 20 operation, Aall required reactor vessel head closure bolts fully tensioned. The required number of head closure bolts is at least 53 of 54 bolts (stud 34 has been removed from service).

(c) For transitioning from the Unit 1 Cycle 18 refueling outage, through Cycle 19, and prior to Cycle 20 operation, Oone or more required reactor vessel head closure bolts less than fully tensioned. The required number of head closure bolts is at least 53 of 54 bolts (stud 34 has been removed from service).

Watts Bar-Unit 1 1.1-7

Enclosure 1 Attachment 2 Proposed TS Change (Final Typed) for WBN Unit 1 CNL-23-043

Definitions 1.1 Table 1.1-1 (page 1 of 1)

MODES

% RATED AVERAGE REACTIVITY THERMAL REACTOR COOLANT MODE TITLE CONDITION POWER (a) TEMPERATURE (keff) (°F) 1 Power Operation 0.99 >5 NA 2 Startup 0.99 <5 NA 3 Hot Standby < 0.99 NA 350 4 Hot Shutdown (b) < 0.99 NA 350 > Tavg > 200 5 Cold Shutdown (b) < 0.99 NA < 200 6 Refueling (c) NA NA NA (a) Excluding decay heat.

(b) For transitioning from the Unit 1 Cycle 18 refueling outage, through Cycle 19, and prior to Cycle 20 operation, all required reactor vessel head closure bolts fully tensioned. The required number of head closure bolts is at least 53 of 54 bolts (stud 34 has been removed from service).

(c) For transitioning from the Unit 1 Cycle 18 refueling outage, through Cycle 19, and prior to Cycle 20 operation, one or more required reactor vessel head closure bolts less than fully tensioned. The required number of head closure bolts is at least 53 of 54 bolts (stud 34 has been removed from service).

Watts Bar-Unit 1 1.1-7

Proprietary Information - Withhold Under 10 CFR § 2.390 Enclosure 2 WCAP-18774-P, Revision 1 (Proprietary)

CNL-23-043 Proprietary Information - Withhold Under 10 CFR § 2.390

Enclosure 3 Westinghouse Electric Company LLC Application for Withholding Proprietary Information from Public Disclosure (Affidavit CAW-23-017)

CNL-23-043

Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-23-017 Page 1 of 2 Commonwealth of Pennsylvania:

County of Butler:

(1) I, Zachary Harper, Senior Manager, Licensing Engineering, have been specifically delegated and authorized to apply for withholding and execute this Affidavit on behalf of Westinghouse Electric Company LLC (Westinghouse).

(2) I am requesting WCAP-18774-P, Revision 1 be withheld from public disclosure under 10 CFR 2.390.

(3) I have personal knowledge of the criteria and procedures utilized by Westinghouse in designating information as a trade secret, privileged, or as confidential commercial or financial information.

(4) Pursuant to 10 CFR 2.390, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.

(i) The information sought to be withheld from public disclosure is owned and has been held in confidence by Westinghouse and is not customarily disclosed to the public.

(ii) The information sought to be withheld is being transmitted to the Commission in confidence and, to Westinghouses knowledge, is not available in public sources.

(iii) Westinghouse notes that a showing of substantial harm is no longer an applicable criterion for analyzing whether a document should be withheld from public disclosure. Nevertheless, public disclosure of this proprietary information is likely to cause substantial harm to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar technical evaluation justifications and licensing defense services for commercial power reactors without commensurate expenses. Also, public disclosure of the information would enable others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information.

Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-23-017 Page 2 of 2 (5) Westinghouse has policies in place to identify proprietary information. Under that system, information is held in confidence if it falls in one or more of several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows:

(a) The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any of Westinghouse's competitors without license from Westinghouse constitutes a competitive economic advantage over other companies.

(b) It consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), the application of which data secures a competitive economic advantage (e.g., by optimization or improved marketability).

(c) Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing a similar product.

(d) It reveals cost or price information, production capacities, budget levels, or commercial strategies of Westinghouse, its customers or suppliers.

(e) It reveals aspects of past, present, or future Westinghouse or customer funded development plans and programs of potential commercial value to Westinghouse.

(f) It contains patentable ideas, for which patent protection may be desirable.

(6) The attached submittal contains proprietary information, for the reasons set forth in Sections (5) (a)-(f) of this Affidavit. The attached submittal is in support of an emergency license amendment request. A redacted version of the submittal will be filed on the docket for public disclosure within 30 days.

I declare that the averments of fact set forth in this Affidavit are true and correct to the best of my knowledge, information, and belief. I declare under penalty of perjury that the foregoing is true and correct.

Executed on: 5/4/2023 _____________________________

Signed electronically by Zachary Harper