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{{#Wiki_filter:Watts Bar Nuclear Plant Units 1 & 2
{{#Wiki_filter:Watts Bar Nuclear Plant Units 1 & 2 May 20, 2024 Pre-Submittal Meeting for Proposed License Amendment Request for Adoption of Technical Specification Task Force Traveler TSTF-276-A, Revision 2, Regarding TS 3.8.1 AC Sources -
Operating to Clarify Requirements for Diesel Generator Testing


Pre-Submittal Meeting for Proposed License Amendment Request for Adoption of Technical Specification Task Force Traveler TSTF -276-A, Revision 2, Regarding TS 3.8.1 AC Sources -
Agenda System Design and Operation Existing Surveillance Requirements Technical Evaluation Regulatory Precedent 2
Operating to Clarify Requirements for Diesel Generator Testing
License Amendment Schedule Proposed Changes to Technical Specification Introduction Reason for Proposed Change


May 20, 2024 Agenda Introduction
Introduction
* TVA is submitting a license amendment request (LAR) for Renewed Facility Operating License Nos. NPF-90 and NPF-96 for Watts Bar Nuclear Plant (WBN), Units 1 and 2 To revise Technical Specification (TS) 3.8.1, AC Sources - Operating Surveillance Requirements (SRs)
Proposed revisions to SRs 3.8.1.9, 3.8.1.10, and 3.8.1.14 to eliminate the specification of kVAR and to specify a power factor of 0.9 during emergency diesel generator surveillance testing Proposed revisions to SR 3.8.1.18 to allow for the surveillance to be performed in Modes 1, 2, 3, or 4 to reestablish operability provided an assessment of plant safety is performed
* Proposed changes are consistent with NUREG-1431, Standard Technical Specifications (STS), Westinghouse Plants, Revision 5, and TSTF-276-A, Revision 2, Revise DG full load rejection test l 3


System Design and Operation
System Design and Operation
Existing Surveillance Requirements
Reason for Proposed Change
Proposed Changes to Technical Specification
Technical Evaluation
Regulatory Precedent
License Amendment Schedule
2 Introduction
* TVA is submitting a license amendment request (LAR) for Renewed Facility Operating License Nos. NPF-90 and NPF -96 for Watts Bar Nuclear Plant (WBN), Units 1 and 2
* To revise Technical Specification (TS) 3.8.1, AC Sources - Operating Surveillance Requirements (SRs)
* Proposed revisions to SRs 3.8.1.9, 3.8.1.10, and 3.8.1.14 to eliminate the specification of k VA R and to specify a power factor of 0.9 during emergency diesel generator surveillance testing
* Proposed revisions to SR 3.8.1.18 to allow for the surveillance to be performed in Modes 1, 2, 3, or 4 to reestablish operability provided an assessment of plant safety is performed
* Proposed changes are consistent with NUREG-1431, Standard Technical Specifications (STS), Westinghouse Plants, Revision 5, and TSTF-276-A, Revision 2, Revise DG full load rejection test
l 3 System Design and Operation
* The WBN Units 1 and 2 Alternating Current (AC) Electrical Power Distribution System AC sources consist of the offsite power sources (preferred power sources, normal, and alternate(s)), and the onsite standby power sources (Train A and Train B DGs).
* The WBN Units 1 and 2 Alternating Current (AC) Electrical Power Distribution System AC sources consist of the offsite power sources (preferred power sources, normal, and alternate(s)), and the onsite standby power sources (Train A and Train B DGs).
* As required by Title 10 of the Code of Federal Regulations (10 CFR) 50, Appendix A, General Design Criteria (GDC) 17, the design of the AC electrical power system provides independence and redundancy to ensure an available source of power to the Engineered Safety Feature (ESF) systems.
* As required by Title 10 of the Code of Federal Regulations (10 CFR) 50, Appendix A, General Design Criteria (GDC) 17, the design of the AC electrical power system provides independence and redundancy to ensure an available source of power to the Engineered Safety Feature (ESF) systems.
* In the event of a loss of preferred power, the 6.9 kV shutdown boards are automatically connected to the DGs in sufficient time to provide for safe reactor shutdown and to mitigate the consequences of a design basis accident (DBA) such as a Loss of Coolant Accident (LOCA).
* In the event of a loss of preferred power, the 6.9 kV shutdown boards are automatically connected to the DGs in sufficient time to provide for safe reactor shutdown and to mitigate the consequences of a design basis accident (DBA) such as a Loss of Coolant Accident (LOCA).
* The onsite Class 1E AC Distribution System supplies electrical power to four power trains, shared between the two units, with each train powered by an independent Class 1E 6.9kV shutdown board. Each 6.9 kV shutdown board has two separate and independent offsite sources of power as well as a dedicated onsite DG source.
* The onsite Class 1E AC Distribution System supplies electrical power to four power trains, shared between the two units, with each train powered by an independent Class 1E 6.9kV shutdown board. Each 6.9 kV shutdown board has two separate and independent offsite sources of power as well as a dedicated onsite DG source.
l 4


l 4 System Design and Operation
System Design and Operation
* Additional DG capabilities must be demonstrated to meet required surveillances
* Additional DG capabilities must be demonstrated to meet required surveillances SR 3.8.1.9 DG single largest load rejection test, SR 3.8.1.10 DG full load rejection test, and SR 3.8.1.14 DG endurance and margin test. These surveillances are performed with the DG synchronized with offsite power. When the DG is not synchronized with offsite power, the power factor is determined by plant load and cannot be adjusted.
* SR 3.8.1.9 DG single largest load rejection test, SR 3.8.1.10 DG full load rejection test, and SR 3.8.1.14 DG endurance and margin test. These surveillances are performed with the DG synchronized with offsite power. When the DG is not synchronized with offsite power, the power factor is determined by plant load and cannot be adjusted.
SR 3.8.1.18 demonstrates sufficient load sequence time delay exists for the DG to restore frequency and voltage prior to applying the next load block and that safety analysis assumptions regarding ESF equipment time delays are not violated.
* SR 3.8.1.18 demonstrates sufficient load sequence time delay exists for the DG to restore frequency and voltage prior to applying the next load block and that safety analysis assumptions regarding ESF equipment time delays are not violated.
l 5


l 5 Existing Surveillance Requirements
Existing Surveillance Requirements
* TS 3.8.1, AC Sources - Operating, SR 3.8.1.9, SR 3.8.1.10, and SR 3.8.1.14, state that when a DG is synchronized with offsite power for load rejection or endurance and margin testing, the SR shall be performed at a power factor of 0.8 and 0.9.
* TS 3.8.1, AC Sources - Operating, SR 3.8.1.9, SR 3.8.1.10, and SR 3.8.1.14, state that when a DG is synchronized with offsite power for load rejection or endurance and margin testing, the SR shall be performed at a power factor of 0.8 and 0.9.
* SR 3.8.1.10 and SR 3.8.1.14 each have a required DG k VA R operating band during performance of the surveillance test.
* SR 3.8.1.10 and SR 3.8.1.14 each have a required DG kVAR operating band during performance of the surveillance test.
* SR 3.8.1.10 band is 2970 k VA R and 3300 k VA R for the entire surveillance test
SR 3.8.1.10 band is 2970 kVAR and 3300 kVAR for the entire surveillance test SR 3.8.1.14 band is 3465 kVAR and 3630 kVAR for at least the first 2 hours and then 2970 kVAR and 3300 kVAR for the remainder of the surveillance test
* SR 3.8.1.14 band is 3465 k VA R and 3630 k VA R for at least the first 2 hours and then 2970 k VA R and 3300 k VA R for the remainder of the surveillance test
* Note for SR 3.8.1.18 states that this surveillance shall not be performed in Mode 1, 2, 3, or 4 and that credit may be taken for unplanned events that satisfy this SR.
* Note for SR 3.8.1.18 states that this surveillance shall not be performed in Mode 1, 2, 3, or 4 and that credit may be taken for unplanned events that satisfy this SR.
l 6


l 6 Reason for Proposed Change
Reason for Proposed Change
* The k VA R requirements in the WBN Units 1 and 2 SRs 3.8.1.10 and 3.8.1.14 were added during the development of the initial Unit 1 TS
* The kVAR requirements in the WBN Units 1 and 2 SRs 3.8.1.10 and 3.8.1.14 were added during the development of the initial Unit 1 TS kVAR requirements for DG surveillances have never been included in Standard TS There are no requirements pertaining to kVAR testing in Regulatory Guide 1.9
* k VA R requirements for DG surveillances have never been included in Standard TS
* When a DG is synchronized with offsite power, a power factor of 0.9 is representative of the inductive loading the DG would experience under design basis accident conditions When the DG is not synchronized with offsite power, the power factor is determined by plant load and cannot be adjusted Under certain grid conditions, the specified power factor may not be achievable The proposed change allows the surveillances to be performed at a power factor as close as practicable to 0.9 l 7
* There are no requirements pertaining to k VA R testing in Regulatory Guide 1.9
* When a DG is synchronized with offsite power, a power factor of 0.9 is representative of the inductive loading the DG would experience under design basis accident conditions
* When the DG is not synchronized with offsite power, the power factor is determined by plant load and cannot be adjusted
* Under certain grid conditions, the specified power factor may not be achievable
* The proposed change allows the surveillances to be performed at a power factor as close as practicable to 0.9


l 7 Reason for Proposed Change
Reason for Proposed Change
* The proposed Note for SR 3.8.1.18 would allow performance of this the surveillance in Modes 1, 2, 3, or 4 to reestablish operability provided an assessment of plant safety is performed
* The proposed Note for SR 3.8.1.18 would allow performance of this the surveillance in Modes 1, 2, 3, or 4 to reestablish operability provided an assessment of plant safety is performed Allows for flexibility in the performance of the surveillance with the appropriate considerations for the potential outcomes and transients associated with a failed surveillance, a successful surveillance, and a perturbation of the offsite or onsite system when they are tied together or operated independently for the surveillance; as well as the operator procedures available to cope with these outcomes.
* Allows for flexibility in the performance of the surveillance with the appropriate considerations for the potential outcomes and transients associated with a failed surveillance, a successful surveillance, and a perturbation of the offsite or onsite system when they are tied together or operated independently for the surveillance; as well as the operator procedures available to cope with these outcomes.
* The changes being proposed align the WBN Units 1 and 2 TS with TSTF-276-A, Revision 2, and the NUREG-1431, Revision 5, Standard TS relative to DG surveillance testing l 8
* The changes being proposed align the WBN Units 1 and 2 TS with TSTF-276-A, Revision 2, and the NUREG-1431, Revision 5, Standard TS relative to DG surveillance testing


l 8 Proposed Changes to Technical Specification Watts Bar Unit 1 is provided and typical of Watts Bar Unit 2
9 Proposed Changes to Technical Specification Watts Bar Unit 1 is provided and typical of Watts Bar Unit 2


99 Proposed Change to Technical Specification Watts Bar Unit 1 is provided and typical of Watts Bar Unit 2
10 10 Proposed Change to Technical Specification Watts Bar Unit 1 is provided and typical of Watts Bar Unit 2


1010 Technical Evaluation
Technical Evaluation
* A power factor of 0.9 is normally achieved when performing this surveillance test while synchronized with offsite power
* A power factor of 0.9 is normally achieved when performing this surveillance test while synchronized with offsite power
* When grid voltage is higher than typical, the additional field excitation current required to achieve a power factor 0.9 results in ESF bus voltage exceeding the maximum steady state voltage limit.
* When grid voltage is higher than typical, the additional field excitation current required to achieve a power factor 0.9 results in ESF bus voltage exceeding the maximum steady state voltage limit.
* Increased grid voltage typically occurs when the plant is shutdown and the loads on the associated ESF transformer are too light to lower the voltage and achieve a 0.9 power factor.
Increased grid voltage typically occurs when the plant is shutdown and the loads on the associated ESF transformer are too light to lower the voltage and achieve a 0.9 power factor.
* Under these conditions, the power factor would be maintained as close as practicable to a 0.9 power factor while still maintaining acceptable voltage limits on the ESF busses.
Under these conditions, the power factor would be maintained as close as practicable to a 0.9 power factor while still maintaining acceptable voltage limits on the ESF busses.
* In other circumstances, the grid voltage may be such that the DG excitation levels needed to obtain a power factor of 0.9 may not cause unacceptable voltages on the emergency busses, but the excitation levels are greater than those recommended for the DG.
* In other circumstances, the grid voltage may be such that the DG excitation levels needed to obtain a power factor of 0.9 may not cause unacceptable voltages on the emergency busses, but the excitation levels are greater than those recommended for the DG.
* In such cases, the power factor would be maintained as close as practicable to 0.9 without exceeding DG excitation limits.
In such cases, the power factor would be maintained as close as practicable to 0.9 without exceeding DG excitation limits.
l 11


l 11 Technical Evaluation
Technical Evaluation
* To confirm that the proposed power factor of 0.9 represents a worst-case power factor for WBN Units 1 and 2, a review was performed of the calculated power factors for each DG during the limiting event of a loss of offsite power (LOOP) coincident with a LOCA.
* To confirm that the proposed power factor of 0.9 represents a worst-case power factor for WBN Units 1 and 2, a review was performed of the calculated power factors for each DG during the limiting event of a loss of offsite power (LOOP) coincident with a LOCA.
* The kW and kVA values associated with the limiting LOOP with a LOCA event time confirm that application of a 0.9 power factor is appropriate for WBN.
The kW and kVA values associated with the limiting LOOP with a LOCA event time confirm that application of a 0.9 power factor is appropriate for WBN.
* The change to Note for SR 3.8.1.18 allows performance of this surveillance in Modes 1, 2, 3, or 4 to reestablish operability provided an assessment of plant safety is performed.
* The change to Note for SR 3.8.1.18 allows performance of this surveillance in Modes 1, 2, 3, or 4 to reestablish operability provided an assessment of plant safety is performed.
* Measured against the avoided risk of a plant shutdown and startup to determine that plant safety is maintained or enhanced when the surveillance is performed in MODE 1, 2, 3, or 4.
Measured against the avoided risk of a plant shutdown and startup to determine that plant safety is maintained or enhanced when the surveillance is performed in MODE 1, 2, 3, or 4.
l 12


l 12 Regulatory Precedent
Regulatory Precedent
* The following licensees have submitted similar license amendment requests which have been reviewed and approved by the NRC
* The following licensees have submitted similar license amendment requests which have been reviewed and approved by the NRC Perry Unit 1 - ML23353A001 issued February 21, 2024 Wolf Creek - ML16081A194 issued April 15, 2016 Palo Verde - ML071060322 issued May 16, 2007 l 13
* Perry Unit 1 - ML23353A001issued February 21, 2024
* Wolf Creek - ML16081A194 issued April 15, 2016
* Palo Verde - ML071060322 issued May 16, 2007
 
l 13 License Amendment Schedule
 
Pre-submittal Meeting with NRC May 20, 2024
 
Submit LAR to NRC June 28, 2024
 
Requested NRC Review and Approval June 2025


14}}
License Amendment Schedule 14 Pre-submittal Meeting with NRC May 20, 2024 Submit LAR to NRC June 28, 2024 Requested NRC Review and Approval June 2025}}

Latest revision as of 18:18, 24 November 2024

Pre-Submittal Meetingfor Proposed License Amendment Request for Adoption of Technical Specification Task Force Traveler TSTF-276-A, Revision 2, Regarding TS 3.8.1 AC Sources - Operating to Clarify Requirements for Diesel Generator Testing
ML24137A287
Person / Time
Site: Watts Bar  Tennessee Valley Authority icon.png
Issue date: 05/16/2024
From:
Tennessee Valley Authority
To:
Office of Nuclear Reactor Regulation
Green K
References
EPID L-2024-LRM-0068 TSTF-276-A, TS 3.8.1
Download: ML24137A287 (1)


Text

Watts Bar Nuclear Plant Units 1 & 2 May 20, 2024 Pre-Submittal Meeting for Proposed License Amendment Request for Adoption of Technical Specification Task Force Traveler TSTF-276-A, Revision 2, Regarding TS 3.8.1 AC Sources -

Operating to Clarify Requirements for Diesel Generator Testing

Agenda System Design and Operation Existing Surveillance Requirements Technical Evaluation Regulatory Precedent 2

License Amendment Schedule Proposed Changes to Technical Specification Introduction Reason for Proposed Change

Introduction

Proposed revisions to SRs 3.8.1.9, 3.8.1.10, and 3.8.1.14 to eliminate the specification of kVAR and to specify a power factor of 0.9 during emergency diesel generator surveillance testing Proposed revisions to SR 3.8.1.18 to allow for the surveillance to be performed in Modes 1, 2, 3, or 4 to reestablish operability provided an assessment of plant safety is performed

  • Proposed changes are consistent with NUREG-1431, Standard Technical Specifications (STS), Westinghouse Plants, Revision 5, and TSTF-276-A, Revision 2, Revise DG full load rejection test l 3

System Design and Operation

  • The WBN Units 1 and 2 Alternating Current (AC) Electrical Power Distribution System AC sources consist of the offsite power sources (preferred power sources, normal, and alternate(s)), and the onsite standby power sources (Train A and Train B DGs).
  • As required by Title 10 of the Code of Federal Regulations (10 CFR) 50, Appendix A, General Design Criteria (GDC) 17, the design of the AC electrical power system provides independence and redundancy to ensure an available source of power to the Engineered Safety Feature (ESF) systems.
  • In the event of a loss of preferred power, the 6.9 kV shutdown boards are automatically connected to the DGs in sufficient time to provide for safe reactor shutdown and to mitigate the consequences of a design basis accident (DBA) such as a Loss of Coolant Accident (LOCA).
  • The onsite Class 1E AC Distribution System supplies electrical power to four power trains, shared between the two units, with each train powered by an independent Class 1E 6.9kV shutdown board. Each 6.9 kV shutdown board has two separate and independent offsite sources of power as well as a dedicated onsite DG source.

l 4

System Design and Operation

  • Additional DG capabilities must be demonstrated to meet required surveillances SR 3.8.1.9 DG single largest load rejection test, SR 3.8.1.10 DG full load rejection test, and SR 3.8.1.14 DG endurance and margin test. These surveillances are performed with the DG synchronized with offsite power. When the DG is not synchronized with offsite power, the power factor is determined by plant load and cannot be adjusted.

SR 3.8.1.18 demonstrates sufficient load sequence time delay exists for the DG to restore frequency and voltage prior to applying the next load block and that safety analysis assumptions regarding ESF equipment time delays are not violated.

l 5

Existing Surveillance Requirements

  • SR 3.8.1.10 and SR 3.8.1.14 each have a required DG kVAR operating band during performance of the surveillance test.

SR 3.8.1.10 band is 2970 kVAR and 3300 kVAR for the entire surveillance test SR 3.8.1.14 band is 3465 kVAR and 3630 kVAR for at least the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and then 2970 kVAR and 3300 kVAR for the remainder of the surveillance test

  • Note for SR 3.8.1.18 states that this surveillance shall not be performed in Mode 1, 2, 3, or 4 and that credit may be taken for unplanned events that satisfy this SR.

l 6

Reason for Proposed Change

  • The kVAR requirements in the WBN Units 1 and 2 SRs 3.8.1.10 and 3.8.1.14 were added during the development of the initial Unit 1 TS kVAR requirements for DG surveillances have never been included in Standard TS There are no requirements pertaining to kVAR testing in Regulatory Guide 1.9
  • When a DG is synchronized with offsite power, a power factor of 0.9 is representative of the inductive loading the DG would experience under design basis accident conditions When the DG is not synchronized with offsite power, the power factor is determined by plant load and cannot be adjusted Under certain grid conditions, the specified power factor may not be achievable The proposed change allows the surveillances to be performed at a power factor as close as practicable to 0.9 l 7

Reason for Proposed Change

  • The proposed Note for SR 3.8.1.18 would allow performance of this the surveillance in Modes 1, 2, 3, or 4 to reestablish operability provided an assessment of plant safety is performed Allows for flexibility in the performance of the surveillance with the appropriate considerations for the potential outcomes and transients associated with a failed surveillance, a successful surveillance, and a perturbation of the offsite or onsite system when they are tied together or operated independently for the surveillance; as well as the operator procedures available to cope with these outcomes.
  • The changes being proposed align the WBN Units 1 and 2 TS with TSTF-276-A, Revision 2, and the NUREG-1431, Revision 5, Standard TS relative to DG surveillance testing l 8

9 Proposed Changes to Technical Specification Watts Bar Unit 1 is provided and typical of Watts Bar Unit 2

10 10 Proposed Change to Technical Specification Watts Bar Unit 1 is provided and typical of Watts Bar Unit 2

Technical Evaluation

  • A power factor of 0.9 is normally achieved when performing this surveillance test while synchronized with offsite power
  • When grid voltage is higher than typical, the additional field excitation current required to achieve a power factor 0.9 results in ESF bus voltage exceeding the maximum steady state voltage limit.

Increased grid voltage typically occurs when the plant is shutdown and the loads on the associated ESF transformer are too light to lower the voltage and achieve a 0.9 power factor.

Under these conditions, the power factor would be maintained as close as practicable to a 0.9 power factor while still maintaining acceptable voltage limits on the ESF busses.

  • In other circumstances, the grid voltage may be such that the DG excitation levels needed to obtain a power factor of 0.9 may not cause unacceptable voltages on the emergency busses, but the excitation levels are greater than those recommended for the DG.

In such cases, the power factor would be maintained as close as practicable to 0.9 without exceeding DG excitation limits.

l 11

Technical Evaluation

  • To confirm that the proposed power factor of 0.9 represents a worst-case power factor for WBN Units 1 and 2, a review was performed of the calculated power factors for each DG during the limiting event of a loss of offsite power (LOOP) coincident with a LOCA.

The kW and kVA values associated with the limiting LOOP with a LOCA event time confirm that application of a 0.9 power factor is appropriate for WBN.

  • The change to Note for SR 3.8.1.18 allows performance of this surveillance in Modes 1, 2, 3, or 4 to reestablish operability provided an assessment of plant safety is performed.

Measured against the avoided risk of a plant shutdown and startup to determine that plant safety is maintained or enhanced when the surveillance is performed in MODE 1, 2, 3, or 4.

l 12

Regulatory Precedent

  • The following licensees have submitted similar license amendment requests which have been reviewed and approved by the NRC Perry Unit 1 - ML23353A001 issued February 21, 2024 Wolf Creek - ML16081A194 issued April 15, 2016 Palo Verde - ML071060322 issued May 16, 2007 l 13

License Amendment Schedule 14 Pre-submittal Meeting with NRC May 20, 2024 Submit LAR to NRC June 28, 2024 Requested NRC Review and Approval June 2025