ML22187A019
| ML22187A019 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 09/20/2022 |
| From: | Kimberly Green Plant Licensing Branch II |
| To: | Jim Barstow Tennessee Valley Authority |
| Green K | |
| References | |
| EPID L-2022-LLA-0026 | |
| Download: ML22187A019 (14) | |
Text
September 20, 2022 Mr. James Barstow Vice President, Nuclear Regulatory Affairs and Support Services Tennessee Valley Authority 1101 Market Street, LP 4A-C Chattanooga, TN 37402-2801
SUBJECT:
WATTS BAR NUCLEAR PLANT, UNIT 1 - ISSUANCE OF AMENDMENT NO. 154 REGARDING REVISION TO TECHNICAL SPECIFICATION 3.3.2 TO REVISE ALLOWABLE VALUE FOR TRIP OF TURBINE-DRIVEN MAIN FEEDWATER PUMPS (EPID L-2022-LLA-0026)
Dear Mr. Barstow:
The U.S. Nuclear Regulatory Commission (Commission) has issued the enclosed Amendment No. 154 to Facility Operating License No. NPF-90 for the Watts Bar Nuclear Plant, Unit 1. This amendment is in response to your application dated February 17, 2022.
The amendment revises the allowable value for Technical Specification (TS) 3.3.2, Engineered Safety Feature Actuation System (ESFAS) Instrumentation, Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, Function 6.e(1), Auxiliary Feedwater - Trip of all Main Feedwater Pumps - Turbine Driven Main Feedwater Pumps, to be consistent with the value for Watts Bar Nuclear Plant, Unit 2.
A copy of our related safety evaluation is also enclosed. Notice of issuance will be included in the Commissions monthly Federal Register notice.
Sincerely,
/RA/
Kimberly J. Green, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-390
Enclosures:
- 1. Amendment No. 154 to NPF-90
- 2. Safety Evaluation cc: Listserv
TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-390 WATTS BAR NUCLEAR PLANT, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 154 License No. NPF-90
- 1.
The U.S. Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Tennessee Valley Authority (TVA, the licensee) dated February 17, 2022, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commissions rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commissions regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commissions regulations and all applicable requirements have been satisfied.
J. Barstow 2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Facility Operating License No. NPF-90 is hereby amended to read as follows:
(2)
Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A as revised through Amendment No. 154 and the Environmental Protection Plan contained in Appendix B, both of which are attached hereto, are hereby incorporated into this license. TVA shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
3.
This license amendment is effective as of the date of its issuance, and shall be implemented within 60 days.
FOR THE NUCLEAR REGULATORY COMMISSION David J. Wrona, Chief Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Attachment:
Changes to the Operating License and Technical Specifications Date of Issuance: September 20, 2022 David J.
Wrona Digitally signed by David J. Wrona Date: 2022.09.20 15:11:47 -04'00'
ATTACHMENT TO AMENDMENT NO. 154 WATTS BAR NUCLEAR PLANT, UNIT 1 FACILITY OPERATING LICENSE NO. NPF-90 DOCKET NO. 50-390 Replace page 3 of Facility Operating License No. NPF-90 with the attached revised page 3.
The revised page is identified by amendment number and contains a marginal line indicating the area of change.
Replace the following page of the Appendix A Technical Specifications with the attached page.
The revised page is identified by amendment number and contains a marginal line indicating the area of change.
Remove Page Insert Page 3.3-38 3.3-38
Amendment No. 154 Facility License No. NPF-90 (4)
TVA, pursuant to the Act and 10 CFR Parts 30, 40 and 70, to receive, possess, and use in amounts as required, any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis, instrument calibration, or other activity associated with radioactive apparatus or components; and (5)
TVA, pursuant to the Act and 10 CFR Parts 30, 40 and 70, to possess, but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility.
C.
This license shall be deemed to contain and is subject to the conditions specified in the Commissions regulations set forth in 10 CFR Chapter I and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect, and is subject to the additional conditions specified or incorporated below.
(1)
Maximum Power Level TVA is authorized to operate the facility at reactor core power levels not in excess of 3459 megawatts thermal.
(2)
Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A as revised through Amendment No. 154 and the Environmental Protection Plan contained in Appendix B, both of which are attached hereto, are hereby incorporated into this license. TVA shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
(3)
Safety Parameter Display System (SPDS) (Section 18.2 of SER Supplements 5 and 15)
Prior to startup following the first refueling outage, TVA shall accomplish the necessary activities, provide acceptable responses, and implement all proposed corrective actions related to having the Watts Bar Unit 1 SPDS operational.
(4)
Vehicle Bomb Control Program (Section 13.6.9 of SSER 20)
During the period of the exemption granted in paragraph 2.D.(3) of this license, in implementing the power ascension phase of the approved initial test program, TVA shall not exceed 50% power until the requirements of 10 CFR 73.55(c)(7) and (8) are fully implemented. TVA shall submit a letter under oath or affirmation when the requirements of 73.55(c)(7) and (8) have been fully implemented.
ESFAS Instrumentation 3.3.2 Watts Bar-Unit 1 3.3-38 Amendment 1, 75, 104, 148, Table 3.3.2-1 (page 5 of 7)
Engineered Safety Feature Actuation System Instrumentation FUNCTION APPLICABLE MODES OR OTHER SPECIFIED CONDITIONS REQUIRED CHANNELS CONDITIONS SURVEILLANCE REQUIREMENTS ALLOWABLE VALUE NOMINAL TRIP SETPOINT 6.
Auxiliary Feedwater (continued) c.
Safety Refer to Function 1 (Safety Injection) for all initiation functions and requirements.
Injection d.
Loss of Offsite 1, 2,3 4 per bus F
Refer to Function 4 of Table 3.3.5-1 for Power SRs and Allowable Values e.
Trip of all Main Feedwater Pumps (1)
Turbine Driven Main Feedwater Pumps 1( i ), 2 1 per pump J
SR 3.3.2.8 SR 3.3.2.9 SR 3.3.2.10 43.3 psig 50 psig and (2)
Standby Main Feedwater Pump 1, 2 1
P SR 3.3.2.8 SR 3.3.2.10 SR 3.3.2.12 NA NA f.
Auxiliary Feedwater Pumps Train A and BG Suction Transfer on Suction Pressure - Low 1, 2, 3, 4(k) 3 B
SR 3.3.2.6 SR 3.3.2.9 SR 3.3.2.10 A) 0.5 psig A) 1.2 psig B) 1.33 psig B) 2.0 psig 7.
Automatic Switchover to Containment Sump a.
Automatic 1, 2, 3, 4 2 trains C
SR 3.3.2.2 NA NA Actuation Logic SR 3.3.2.3 and Actuation SR 3.3.2.5 Relays (continued)
( i )
Entry into Condition J may be suspended for up to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> when placing the second Turbine Driven Main Feedwater (TDMFW) Pump in service or removing a TDMFW pump from service.
( j )
Deleted.
( k )
When steam generators are relied on for heat removal.
154
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 154 TO FACILITY OPERATING LICENSE NO. NPF-90 TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 1 DOCKET NO. 50-390
1.0 INTRODUCTION
By letter dated February 17, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22049A031), the Tennessee Valley Authority (TVA, the licensee),
submitted a license amendment request (LAR) to revise the Watts Bar Nuclear Plant (Watts Bar), Unit 1 Technical Specifications (TSs). The requested changes would revise the allowable value (AV) for Watts Bar, Unit 1, TS 3.3.2, Engineered Safety Feature Actuation System (ESFAS) Instrumentation, Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, Function 6.e(1), Auxiliary Feedwater - Trip of all Main Feedwater Pumps -
Turbine Driven Main Feedwater Pumps.
2.0 REGULATORY EVALUATION
2.1
System Description
The proposed change to the Watts Bar Unit 1, TSs is associated with the design and operation of the main feedwater (MFW) and the auxiliary feedwater (AFW) systems.
2.1.1 Main Feedwater System The MFW system includes two turbine-driven MFW pumps (TDMFWPs), one electric motor-driven standby MFW pump (SBMFWP), with high-and low-pressure feedwater (FW) heaters, demineralizers, and other equipment needed to process feedwater flow. The two variable-speed TDMFWPs can deliver feedwater to the four steam generators (SGs) under all expected operating conditions. The normal operating pressure of the TDMFWP is between 135 and 155 pounds per square inch gauge (psig).
The MFW system is described in Section 10.4.7.2 of the Watts Bar Updated Final Safety Analysis Report (UFSAR) (ML20323A305).
2.1.2 Auxiliary Feedwater System The AFW system provides a secondary side heat sink for the reactor if the MFW system is not available. The system has two motor-driven pumps and a turbine-driven pump.
The two motor-driven AFW pumps and one turbine-driven pump are configured into three trains.
Each motor-driven AFW pump is powered from an independent Class 1E power supply and feeds two SGs. The turbine-driven AFW pump receives steam from one of two main steam lines upstream of the main steam isolation valves. Each of the steam feed lines will supply 100 percent of the requirements of the turbine-driven AFW pump. The turbine-driven AFW pump supplies a common header capable of feeding all SGs. The AFW system is normally aligned so that upon a pump start, flow is initiated to the respective SGs.
The AFW system actuates automatically on SG low-low level by the ESFAS. The motor-driven AFW pumps start on a two-out-of-three low-low level signal in any SG and the turbine-driven pump starts on a two-out-of-three low-low level signal in any two SGs. The system also actuates on loss of offsite power, safety injection, and trip of both TDMFWPs.
The subject of this LAR is the automatic AFW actuation on trip of both TDMFWPs when the SBMFWP is tripped. Each TDMFWP is equipped with a pressure switch which measures control oil line pressure for the speed control system of that pump. When a turbine trip occurs, the control oil pressure decreases causing the pressure switch to change state, resulting in a pump trip signal and a plant annunciator alarm.
The electric motor-driven SBMFWP trip channel is provided by breaker contacts from the supply breaker of the motor driven SBMFWP in the AFW start logic. The breaker contacts monitor the SBMFWP and close upon the opening of the breaker, indicating that the pump has tripped.
The trip of both TDMFWPs and the SBMFWP pump will start the motor-driven and turbine-driven AFW pumps to ensure that enough water is available to act as the heat sink for the reactor.
The AFW system is described in Section 10.4.9 of the Watts Bar UFSAR (ML20323A305).
2.2 Requested Changes The licensee proposed to revise the AV for Watts Bar, Unit 1, TS 3.3.2, Engineered Safety Feature Actuation System (ESFAS) Instrumentation, Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, Function 6.e(1), Auxiliary Feedwater - Trip of all Main Feedwater Pumps - Turbine Driven Main Feedwater Pumps, from 48 psig to 43.3 psig for consistency with the AV for Watts Bar, Unit 2, TS Table 3.3.2-1, Function 6.e(1).
2.3 Regulations and Guidance The NRC staff's evaluation is based upon the following regulations and guidance.
Under Title 10 of the Code of Federal Regulations (10 CFR) 50.92(a), determinations on whether to grant an applied-for license amendment are to be guided by the considerations that govern the issuance of initial licenses to the extent applicable and appropriate. Both the common standards for licenses in 10 CFR 50.40(a), and those specifically for issuance of operating licenses in 10 CFR 50.57(a)(3), provide that there must be reasonable assurance that the activities at issue will not endanger the health and safety of the public, and that the applicant will comply with the NRC's regulations.
Pursuant to 10 CFR 50.36, Technical specifications, TSs for operating reactors are required, in part, to include items in the following five specific categories: (1) safety limits, limiting safety system settings, and limiting control settings; (2) limiting conditions for operation (LCOs);
(3) surveillance requirements (SRs); (4) design features; and (5) administrative controls.
Section 50.36(a)(1) of 10 CFR requires each applicant for a license authorizing operation of a production or utilization facility to include a summary statement of the bases or reasons for proposed TSs, other than those covering administrative controls; however, the bases shall not become part of the TSs.
Section 50.36(b) of 10 CFR requires that each license authorizing reactor operation include TSs derived from the analyses and evaluation included in the safety analysis report and amendments thereto.
Section 50.36(c) of 10 CFR requires that TSs include certain items. Per 10 CFR 50.36(c)(2)(i),
the TSs must include LCOs, which are the lowest functional capability or performance levels of equipment required for safe operation of the facility. That provision also requires that when an LCO of a nuclear reactor is not met, the licensee must shut down the reactor or follow any remedial action permitted by the TSs until the condition can be met.
Section 50.36(c)(3) of 10 CFR requires that TSs include SRs, which are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the LCOs will be met.
Regulatory Guide (RG) 1.105, Setpoints for Safety-Related Instrumentation (ML20330A329),
describes a method acceptable to the NRC staff for complying with the NRCs regulations for ensuring that setpoints for safety-related instrumentation are initially within and remain within the TS limits. RG 1.105, Revision 4, endorses National Standards Institute/International Society of Automation (ANSI/ISA) Standard 67.04.01-2018, Setpoints for Nuclear Safety-Related Instrumentation. The NRC staff used this guide to establish the adequacy of the licensees setpoint calculation methodologies and the related plant surveillance procedures.
The NRC staffs guidance for the review of TSs is in NUREG-0800, Standard Review Plan
[SRP] for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light Water Reactor] Edition, Chapter 16.0, Technical Specifications, Revision 3, dated March 2010 (ML100351425).
Information Notice 2015-05, Inoperability of Auxiliary and Emergency Feedwater Auto-Start Circuits on Loss of Main Feedwater Pumps (ML150084A493), informs holders of operating licenses for nuclear power reactors of several instances between 2006 and 2012 where licensees operated their MFW systems in such a manner that the automatic initiation of auxiliary or emergency FW on loss of all MFW pumps was disabled.
3.0 TECHNICAL EVALUATION
3.1 Background
In Section 2.4 of the LAR enclosure, the licensee explained the reason for its requested change to the AV in Table 3.3.2-1, Engineered Safety Feature Actuation System Instrumentation, Function 6.e(1), Auxiliary Feedwater - Trip of all Main Feedwater Pumps - Turbine Driven Main Feedwater Pumps.
The licensee evaluated the historical TS surveillance data for the pressure switches that perform function 6.e(1) and identified several occurrences where the as-found instrument values were outside the AV limit of 48 psig. The licensee stated that it implemented its corrective action program to investigate these occurrences and determined that the AV setpoint for this function was too limiting because it did not adequately account for the accuracy and repeatability of the switches for their TS nominal trip setpoint. The NRC staff notes that the nominal trip setpoint for these pressure switches is not being changed.
The proposed change to the AV setpoint is supported by an updated calculation that the licensee performed to determine the new proposed AV setpoint that accounts for the normal measurement accuracy of the pressure switches performing this function. The proposed TS change also aligns the AV for Watts Bar, Unit 1, TS 3.3.2, Table 3.3.2-1, Function 6.e(1) with the existing AV for Watts Bar, Unit 2, TS 3.3.2, Table 3.3.2-1, Function 6.e(1).
3.2 Detailed Description and Evaluation of Proposed Allowable Value Setpoint Change The proposed change revises the AV for Watts Bar, Unit 1, TS 3.3.2, Table 3.3.2-1, Function 6.e(1) from 48 psig to 43.3 psig. In the LAR, Attachment 1 to the Enclosure provides the existing Watts Bar, Unit 1, TS page marked to show the proposed change. In the LAR, Attachment 2 to the Enclosure provides the Watts Bar, Unit 1 TS page retyped to show the proposed change.
The proposed TS AV setpoint change is supported by an instrument uncertainty calculation and a technical evaluation provided in Section 3.0 of the LAR enclosure. Section 3.2, Calculation of New AV, of Attachment 1 to the LAR enclosure includes a summary of this uncertainty calculation.
The licensee stated that the affected Function 6.e(1) trip/alarm is anticipatory because it is not credited in any of the Watts Bar UFSAR Chapter 15 accident analyses. Because of this, there is no safety limit or analytical limit associated with this trip/alarm setpoint.
The NRC staff determined that the change to the AV setpoint does not affect the function of detecting the trip of the associated MFW pump because the control oil pressure will depressurize when the MFW pump is tripped causing the pressure switch to change state and initiate the MFW pump trip signal to the AFW actuation circuit. As such, the proposed AV setpoint change to the AFW auto-start function will not adversely impact AFW system operation, flow capabilities, or its response to accidents.
The affected Function 6.e(1) provides a signal input to support an anticipatory auto-start of the AFW system when the MFW pumps trip and cause a loss of normal feedwater flow. The licensee calculated a new plant-specific AV using the current switch setpoint which is the normal setpoint (50 psig) minus the normal measurable accuracy of the pressure switches that perform this function. The licensee determined the normal measurable accuracy for this pressure switch to be 6.7 psig, based on calculation provided in the LAR resulting in the new AV of 43.3 psig.
The NRC staff verified the licensees setpoint calculation methodology, which used a square root of the sum of the squares (SRSS) approach as the means of combining normally distributed and independent uncertainty terms. There were no uncertainty terms that were not random, not normally distributed nor dependent; therefore, no algebraically added uncertainty terms were included in the calculation.
The NRC staff finds that the SRSS methodology used to calculate the proposed AVs is consistent with the methodology in Section 4.5.1, Combination of uncertainties (SRSS method), of Part I of ANSI/ISA S67.04.01-2018 and RG 1.105, Revision 4, and provides reasonable assurance that the proposed setpoints were established and will be maintained in a manner consistent with plant safety function requirements. Equations used in the calculations are, therefore, consistent with the guidance in RG 1.105.
Because there are no analytical limits associated with the AV setpoints being changed, it was not necessary for the NRC staff to verify the AV setpoints provide adequate margin or assurance that analytical limits will not be exceeded.
TS 3.3.2 Table 1, Function 6.e(1), imposes an anticipatory function that provides early actuation of the AFW system in the event of a loss of normal FW but is not credited in the Watts Bar accident analyses for actuation of the AFW system. The Watts Bar accident analysis in UFSAR Section 15.2.8, Loss of Normal Feedwater, (ML20323A316) credits the initiation of the AFW system by SG low-low water level for mitigating the loss of normal FW.
The NRC staff reviewed the LAR and Watts Bar UFSAR and confirmed that Function 6.e(1) is an anticipatory function that provides early actuation of the AFW system for the loss of normal FW and is not credited in the Watts Bar accident analyses. The credited UFSAR Section 15.2.8 design basis function AFW auto-start channels are associated with steam generator low-low levels and remain unchanged.
Based on the NRC staffs review of information provided by the licensee in the LAR and the Watts Bar UFSAR, the NRC staff concludes that the operation of the MFW pump after the implementation of the proposed Function 6.e(1) AV setpoint change will not affect the anticipatory AFW automatic start from the trip of the MFW pumps.
3.3 Evaluation of Proposed Technical Specification Change The licensee provided markups of the TSs showing the proposed change in its LAR. The change is evaluated as follows.
The NRC staff evaluated the licensees LAR to determine if the proposed change is consistent with the guidance, regulations, and licensing information discussed in Section 2.3 of this safety evaluation. In determining whether an amendment to a license will be issued, the Commission is guided by the considerations that govern the issuance of initial licenses to the extent applicable and appropriate.
The NRC staff reviewed the licensees proposal to revise the AV for Function 6.e(1) of Table 3.3.2-1 to 43.3 psig.
The NRC staff finds that the proposed change is acceptable because the AFW low SG level actuation functions that are credited in the plant accident analyses will remain operable and because the operation of the MFW pump will continue to support the anticipatory AFW automatic start from the trip of the MFW pumps when the SBMFWP is not running.
3.4 Summary and Technical Conclusion The NRC staff has determined that the LAR properly identifies the revised Function 6.e(1) AV setpoint. The SRs specify the test requirements for the plant pressure switches that perform this function, thus ensuring compliance with 10 CFR 50.36(c)(3). Because the ability of the SG low-low level safety channels to perform their safety function to automatically start the AFW system will be retained, the NRC staff concludes that the proposed change is acceptable and that the TS, as revised, will continue to meet the requirements of 10 CFR 50.36(c)(2)(i) to include LCOs and 10 CFR 50.36(c)(3) to include SRs.
4.0 STATE CONSULTATION
In accordance with the Commissions regulations, the Tennessee State official was notified of the proposed issuance of the amendment on June 28, 2022. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission previously issued a proposed finding that the amendment involves no significant hazards consideration published in the Federal Register on April 19, 2022 (87 FR 23270), and there has been no public comment on such finding. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) there is reasonable assurance that 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.
Principal Contributor: R. Stattel, NRR Date: September 20, 2022
ML22187A019 OFFICE NRR/DORL/LPL2-2/PM NRR/DORL/LPL2-2/LA NRR/DEX/EICB/BC NRR/DSS/SCPB/BC NAME KGreen RButler MWaters BWittick DATE 7/1/22 7/7/22 6/23/22 7/8/22 OFFICE NRR/DSS/STSB/BC OGC - NLO w/comments NRR/DORL/LPL2-2/BC NRR/DORL/LPL2-2/PM NAME VCusumano JEzell DWrona KGreen DATE 7/6/22 7/25/22 9/20/22 9/20/22