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Category:Meeting Briefing Package/Handouts
MONTHYEARML23291A1562023-10-18018 October 2023 NRC Pre-Submittal Meeting Watts Bar & Sequoyah LAR, TVA Presentation Slides ML23264A0412023-09-27027 September 2023 NRC Pre-Submittal Meeting WBN Rebaseline LAR, TVA Presentation Slides ML23251A1212023-09-12012 September 2023 RHR Flow Rate Reduction During Mode 6 Operation at 23 Ft. Refueling Water Level Technical Specification Change NON-PROPRIETARY Slides ML23251A1252023-09-12012 September 2023 Pre-submittal Meeting for License Amendment Request, Modify the Watts Bar Nuclear Plant Unit 1 and Unit 2 Technical Specification Surveillance Requirement 3.9.5.1 ML23178A0832023-07-10010 July 2023 Pre-submittal Meeting Slides for License Amendment Request to Revise Technical Specification Table 1.1-1 Regarding the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs ML23128A2882023-05-0808 May 2023 TVA Nuclear Plants -2022 EOC Media Slides ML23052A0362023-02-22022 February 2023 February 22, 2023, Pre-Submittal Meeting for the License Amendment Request for Increased Tritium Production at Watts Bar (EPID L-2023-LRM-0010) - Meeting Slides ML23044A5182023-02-15015 February 2023 Pre-Submittal Meeting Slides for Expedited License Amendment Request Re Main Control Room Chiller Completion Time Extension ML23041A3562023-02-15015 February 2023 February 15, 2023 Pre-submittal Meeting for Expedited License Amendment Request Main Control Room (MCR) Chiller Completion Time Extension (EPID L-2022-LRM-0098) (Slides) ML22318A1042022-11-14014 November 2022 Pre-submittal Meeting for American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI, Request for Alternative WBN-2-ISI-01 Slide Presentation ML22157A4132022-06-0606 June 2022 Plants - Pre-Submittal Teleconference for Proposed Amendment Request Regarding the Change for the Sequoyah and Watts Bar Nuclear Plants Technical Specification 3.4.12 Meeting Slides ML22102A3032022-04-12012 April 2022 Pre-submittal Meeting for Request for Exemption from Requirements of 10 CFR 26.205(d)(4) and 10 CFR 26.205(d)(6) Slide Presentation ML22080A1662022-03-21021 March 2022 TVA Nuclear Plants -2021 EOC Media Loop Slides for Automatic Play ML21343A0282021-12-14014 December 2021 TVA Slide Presentation Regarding Pre-Submittal Meeting for Proposed Revision to Capsule Withdrawal Schedule ML21281A2282021-10-13013 October 2021 Tennessee Valley Authority Fleet Pre-Submittal Meeting for License Amendment Request to Change Emergency Action Level Scheme Presentation - October 13, 2021 (EPID L-2021-LRM-0096) (Slides) ML21250A3652021-09-0808 September 2021 Meeting Slides - Watts Bar Nuclear Plant Unit 2, Presubmittal Teleconference for Proposed License Amendment to Revise the Updated Final Safety Analyses Report (UFSAR) to Use a Tube Support Plate Locking/Displacement Analysis ML21217A2872021-08-19019 August 2021 TVA Slides - Pre-Submittal Meeting for Proposed License Amendment Request Re Application to Modify Technical Specification 3.7.8 Essential Raw Cooling Water (ERCW) System, to Support Permanent Shutdown Board ML21229A1992021-08-19019 August 2021 Mid-Cycle SG Outage Strategy (EPID L-2021-LRM-0067) (Slides) ML21231A0972021-08-18018 August 2021 TVA Slides - Pre-Submittal Meeting for Proposed LAR Regarding Application to Modify Watts Bar Units 1 and 2 Technical Specification 3.7.8, Essential Raw Cooling Water (ERCW) System, to Support Permanent Shutdown Board Cleaning ML21117A0722021-04-27027 April 2021 Meeting Slides for April 28, 2021 Meeting with TVA ML21096A1312021-04-0707 April 2021 Pre-submittal Meeting for Inservice Testing (IST) Program Request for One-Time Extension of Test Frequency of WBN Unit 1 Group 6 Relief Valves ML21041A1552021-02-11011 February 2021 Meeting Slides for February 11, 2021 Meeting with TVA ML20345A0262020-12-10010 December 2020 Replacement Steam Generator Project Planned License Amendment Request (Lars). LAR Descriptions and Submittal Schedule Meeting Slides ML20329A3722020-11-24024 November 2020 Pre-Submittal Teleconference for Proposed License Amendment Request Regarding Technical Specification 5.9.9, Steam Generator Tube Inspection Report, to Use Popcd Methodology ML20302A1232020-10-28028 October 2020 Pre-Submittal Meeting Slides Non-Voluntary Application to Modify WBN Unit 1 and Unit 2 TS Surveillance Requirement 3.6.15.4, Shield Building ML20239A8672020-08-27027 August 2020 Pre-Submittal Meeting Slides License Amendment Request for Technical Specification 5.7.2.19 ML20175A0552020-06-23023 June 2020 TVA Slides for June 23, 2020, Emergency Plan Change Presubmittal Meeting ML20125A3242020-05-0505 May 2020 Pre-Submittal Meeting Slides for License Amendment Request - Main Control Room Chiller Completion Time Extension ML20049G1822020-02-18018 February 2020 February 20, 2020 - Pre-submittal Meeting Presentation - Transition to Westinghouse Fuel ML20009C3962020-01-0808 January 2020 Pre-Submittal Telecon for Expedited License Amendment Request to Revise Technical Specification 3.3.5, LOP DG Start Instrumentation ML19347B0722019-12-12012 December 2019 TVA and Xcel Energy Slides for Joint Presubmittal Meeting to License Amendment Requests to Adopt WCAP-17661, Revision 1 ML19282A0082019-10-0909 October 2019 TVA Slides for Pre-Submittal Meeting for License Amendment Request to Correct Unbalanced Voltage Relay Instrumentation Values ML19255H5522019-09-12012 September 2019 August 27, 2019, Summary of Public Meeting - Tennessee Valley Safety Conscious Work Environment Update at Watts Bar, Docket 50-390 and 50-391 ML19298A0042019-09-12012 September 2019 Presentation Slides for 9/12/19 Public Meeting ML19252A0532019-09-0909 September 2019 TVA Presentation Slides: Watts Bar Nuclear Plant Pre-Submittal Meeting for License Amendment Request Revised Offsite Electrical Power Sources ML19235A2882019-08-23023 August 2019 2019 WBN SCWE Public Meeting Slides 8-27-2019 (NRC Slides) ML19235A2712019-08-23023 August 2019 2019 TVA Watts Bar Nuclear Plant Public Meeting Slides 08-27-2019 (TVA Slides) ML19178A2462019-07-0101 July 2019 Presentation Material for July 1, 2019 Pre-submittal Meeting with TVA on Full Spectrum LOCA Methodology for Watts Bar, Units 1 and 2 ML19161A2412019-06-11011 June 2019 Pre-Application Meeting for Proposed License Amendment Request (LAR) Regarding Change to the WBN Unit 2 Technical Specifications (TS) 3.4.17, Steam Generator Tube Integrity and 5.7.2.12 Steam Generator Program ML19161A2392019-06-10010 June 2019 Plants Pre-Submittal Meeting for Proposed License Amendments Hydrological Analysis Updates June 10, 2019 ML19142A3602019-05-21021 May 2019 May 9, 2019 Summary of Public Meeting; Watts Bar Nuclear Plant ML19018A0072019-01-18018 January 2019 (WBN)Pre-Submittal Meeting for Proposed License Amendment Request Regarding a One-Time Change for the WBN Unit 2 Technical Specification (TS) 3.7.8, Essential Raw Cooling Water (ERCW) System. ML18291A5732018-10-18018 October 2018 Chilled Work Environment ML18291A5632018-10-18018 October 2018 Chilled Worked Environment Update ML18248A1052018-09-0505 September 2018 Presentation Slides - Watts Bar Nuclear Plant Units 1 and 2 Adoption of TSTF-425 Initiative 5b - Surveillance Frequency Control Program - September 6, 2018 ML18248A1022018-09-0505 September 2018 Presentation Slides - Watts Bar Nuclear Plant (WBN) Pre-Submittal Meeting for Proposed License Amendment Request Regarding Shutdown Board Cleaning - September 6, 2018 ML18248A1012018-09-0505 September 2018 Bar Nuclear Plant (WBN) Pre-Submittal Meeting for Proposed License Amendment Adoption of TSTF-500 ML18248A1072018-09-0505 September 2018 Presentation Slides - Watts Bar Nuclear Plant Units 1 and 2 Adoption of 10 CFR 50.69 - September 6, 2018 ML18164A3192018-06-18018 June 2018 Presentation Material for 6/19/18 Pre-submittal Meeting ML18024A7932018-01-25025 January 2018 Presentation Slides - Watts Bar Nuclear Plant Unit 2 Pre-Submittal Meeting for Proposed License Amendment Request Regarding the Use of PAD4TCD in the Large Break Loss of Coolant Accident Analysis 2023-09-27
[Table view] Category:Slides and Viewgraphs
MONTHYEARML23291A1562023-10-18018 October 2023 NRC Pre-Submittal Meeting Watts Bar & Sequoyah LAR, TVA Presentation Slides ML23264A0412023-09-27027 September 2023 NRC Pre-Submittal Meeting WBN Rebaseline LAR, TVA Presentation Slides ML23251A1212023-09-12012 September 2023 RHR Flow Rate Reduction During Mode 6 Operation at 23 Ft. Refueling Water Level Technical Specification Change NON-PROPRIETARY Slides ML23251A1252023-09-12012 September 2023 Pre-submittal Meeting for License Amendment Request, Modify the Watts Bar Nuclear Plant Unit 1 and Unit 2 Technical Specification Surveillance Requirement 3.9.5.1 ML23178A0832023-07-10010 July 2023 Pre-submittal Meeting Slides for License Amendment Request to Revise Technical Specification Table 1.1-1 Regarding the Required Number of Fully Tensioned Reactor Pressure Vessel Head Closure Studs ML23128A2882023-05-0808 May 2023 TVA Nuclear Plants -2022 EOC Media Slides ML23052A0362023-02-22022 February 2023 February 22, 2023, Pre-Submittal Meeting for the License Amendment Request for Increased Tritium Production at Watts Bar (EPID L-2023-LRM-0010) - Meeting Slides ML23044A5182023-02-15015 February 2023 Pre-Submittal Meeting Slides for Expedited License Amendment Request Re Main Control Room Chiller Completion Time Extension ML23041A3562023-02-15015 February 2023 February 15, 2023 Pre-submittal Meeting for Expedited License Amendment Request Main Control Room (MCR) Chiller Completion Time Extension (EPID L-2022-LRM-0098) (Slides) ML23010A2542023-01-12012 January 2023 Pre-submittal Meeting for Expedited License Amendment Request Main Control Room (MCR) Chiller Completion Time Extension -- Meeting Slides ML22318A1042022-11-14014 November 2022 Pre-submittal Meeting for American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI, Request for Alternative WBN-2-ISI-01 Slide Presentation ML22157A4132022-06-0606 June 2022 Plants - Pre-Submittal Teleconference for Proposed Amendment Request Regarding the Change for the Sequoyah and Watts Bar Nuclear Plants Technical Specification 3.4.12 Meeting Slides ML22103A0852022-04-14014 April 2022 and Watts Bar Plant Pre-submittal Meeting for Inservice Testing (IST) Program Request for Alternative for the Motor Driven Auxiliary Feedwater Pump Testing Following Maintenance During an Outage Per ISTB-3310 ML22102A3032022-04-12012 April 2022 Pre-submittal Meeting for Request for Exemption from Requirements of 10 CFR 26.205(d)(4) and 10 CFR 26.205(d)(6) Slide Presentation ML22080A1662022-03-21021 March 2022 TVA Nuclear Plants -2021 EOC Media Loop Slides for Automatic Play ML22035A0002022-02-0404 February 2022 February 8, 2022, Pre-Submittal Meeting Slides Regarding Proposed Change to Modify the Allowable Value for Technical Specification Table 3.3.2-1, Function 6.e(1) ML22013A6432022-01-19019 January 2022 TVA Slides - Watts Bar Nuclear Plant (WBN) Schedule for the Development of a License Amendment Request (LAR) for Increased Tritium Production at WBN ML21343A0282021-12-14014 December 2021 TVA Slide Presentation Regarding Pre-Submittal Meeting for Proposed Revision to Capsule Withdrawal Schedule ML21281A2282021-10-13013 October 2021 Tennessee Valley Authority Fleet Pre-Submittal Meeting for License Amendment Request to Change Emergency Action Level Scheme Presentation - October 13, 2021 (EPID L-2021-LRM-0096) (Slides) ML21250A3652021-09-0808 September 2021 Meeting Slides - Watts Bar Nuclear Plant Unit 2, Presubmittal Teleconference for Proposed License Amendment to Revise the Updated Final Safety Analyses Report (UFSAR) to Use a Tube Support Plate Locking/Displacement Analysis ML21229A1992021-08-19019 August 2021 Mid-Cycle SG Outage Strategy (EPID L-2021-LRM-0067) (Slides) ML21217A2872021-08-19019 August 2021 TVA Slides - Pre-Submittal Meeting for Proposed License Amendment Request Re Application to Modify Technical Specification 3.7.8 Essential Raw Cooling Water (ERCW) System, to Support Permanent Shutdown Board ML21231A0972021-08-18018 August 2021 TVA Slides - Pre-Submittal Meeting for Proposed LAR Regarding Application to Modify Watts Bar Units 1 and 2 Technical Specification 3.7.8, Essential Raw Cooling Water (ERCW) System, to Support Permanent Shutdown Board Cleaning ML21096A1312021-04-0707 April 2021 Pre-submittal Meeting for Inservice Testing (IST) Program Request for One-Time Extension of Test Frequency of WBN Unit 1 Group 6 Relief Valves ML21096A1002021-04-0606 April 2021 Annual Assessments ML21041A1552021-02-11011 February 2021 Meeting Slides for February 11, 2021 Meeting with TVA ML21019A5692021-01-19019 January 2021 Pre-Submittal Teleconference for Proposed License Amendment Requests (Lars) for the WBN Unit 2 Replacement Steam Generator (RSG) Project ML20352A0362020-12-17017 December 2020 Pre-Submittal Teleconference for Proposed License Amendment to Revise the Updated Final Safety Analysis Report (UFSAR) to Use an Alternate Probability of Detection (POD) ML20329A3722020-11-24024 November 2020 Pre-Submittal Teleconference for Proposed License Amendment Request Regarding Technical Specification 5.9.9, Steam Generator Tube Inspection Report, to Use Popcd Methodology ML21050A1562020-10-21021 October 2020 Graizer - Presentation - Analysis of Tva'S Watts Bar Nuclear Power Plant Strong-Motion Records of the M 4.4 December 12, 2018 Decatur Tennessee Earthquake ML20239A8672020-08-27027 August 2020 Pre-Submittal Meeting Slides License Amendment Request for Technical Specification 5.7.2.19 ML20220A2022020-08-0707 August 2020 Pre-Submittal Meeting Slides - Proposed License Approach Regarding a Change for Watts Bar Nuclear Plant Units 1 & 2 Technical Specification 3.3.2 Table 1 Function 6.e Auxiliary Feedwater Auto-Start from Loss of Main Feedwater Pumps(Epid L-2 ML20209A0702020-07-27027 July 2020 Pre-submittal Meeting for Inservice Testing (IST) Program Request for Relief from Increased Frequency Testing of Residual Heat Removal (RHR) Pump 1B-B Meeting Slides ML20169A5222020-06-25025 June 2020 Pre-Submittal Meeting for License Amendment Request (LAR) Revised Steam Generator (SG) Inspection Intervals and TSTF-510 ML20175A0552020-06-23023 June 2020 TVA Slides for June 23, 2020, Emergency Plan Change Presubmittal Meeting ML20148M1452020-05-27027 May 2020 (Wbn)Proposed License Approach Regarding a Change for the WBN Units 1& 2 Technical Specification (TS) 3.3.2 Table 1 Function 6.e Auxiliary Feedwater Auto-Start from Loss of Main Feedwater Pumps ML20147A0132020-05-26026 May 2020 NRC Slides Final WBN-1 TS 3.3.3 LAR ML20134J0102020-05-14014 May 2020 Pre-Submittal Meeting for License Amendment Request Technical Specification 5.9.6 Add NRC-approved Neutron Fluence Calculational Methodology ML20125A3242020-05-0505 May 2020 Pre-Submittal Meeting Slides for License Amendment Request - Main Control Room Chiller Completion Time Extension ML20112F5302020-04-21021 April 2020 TVA Nuclear Plants -2019 EOC Media Loop Slides for Automatic Play (Final) ML20049G1822020-02-18018 February 2020 February 20, 2020 - Pre-submittal Meeting Presentation - Transition to Westinghouse Fuel ML20009C3962020-01-0808 January 2020 Pre-Submittal Telecon for Expedited License Amendment Request to Revise Technical Specification 3.3.5, LOP DG Start Instrumentation ML19282A0082019-10-0909 October 2019 TVA Slides for Pre-Submittal Meeting for License Amendment Request to Correct Unbalanced Voltage Relay Instrumentation Values ML19298A0042019-09-12012 September 2019 Presentation Slides for 9/12/19 Public Meeting ML19255H5522019-09-12012 September 2019 August 27, 2019, Summary of Public Meeting - Tennessee Valley Safety Conscious Work Environment Update at Watts Bar, Docket 50-390 and 50-391 ML19252A0532019-09-0909 September 2019 TVA Presentation Slides: Watts Bar Nuclear Plant Pre-Submittal Meeting for License Amendment Request Revised Offsite Electrical Power Sources ML19252A0522019-09-0909 September 2019 TVA Presentation Slides: Watts Bar Nuclear Plant (WBN) Application to Modify WBN Unit 1 and Unit 2 Technical Specification (TS) 3.6.15, Shield Building - September 11, 2019 ML19235A2712019-08-23023 August 2019 2019 TVA Watts Bar Nuclear Plant Public Meeting Slides 08-27-2019 (TVA Slides) ML19197A0932019-07-16016 July 2019 Presentation Slides - Watts Bar Nuclear Plant (WBN) Unit 2, Pre-Submittal Meeting for License Amendment Request Measurement Uncertainty Recapture (Mur) Power Update ML19178A2462019-07-0101 July 2019 Presentation Material for July 1, 2019 Pre-submittal Meeting with TVA on Full Spectrum LOCA Methodology for Watts Bar, Units 1 and 2 2023-09-27
[Table view] |
Text
Watts Bar Nuclear Plant Diesel Generator Completion Time Extension August 4, 2016
Agenda
- TS Completion Time (CT) History
- Discussion of NRC Questions
- Closing Remarks Watts Bar Nuclear Plant - DG CT Extension l 2
Opening Remarks Watts Bar Nuclear Plant - DG CT Extension l 3
WBN Completion Time History
- Original WBN Unit 1 Technical Specification
- 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time for One Inoperable Diesel Generator (DG)
- December 08 2000
- One Time - 10 day completion time
- July 7, 2002
- 14 Day Completion Time
- Risk-Informed Based on Unit 1 Operation Only
- July 6, 2010
- 72 Hour Completion Time
- Implementation Delayed for Unit 1 until Prior to Unit 2 Entering MODE 4
- WBN Unit 2 Operating License
- October 22, 2015
- 72 Hour Completion Time
- WBN Unit 2 Entered Mode 4
- March 17, 2016 Implemented WBN Unit 1 72 Hour CT
- March 19, 2016 WBN U2 Entered Mode 4 Watts Bar Nuclear Plant - DG CT Extension l 4
System Overview
- Grid and Interconnections
- 500 kV (Power Distribution)
- 161 kV (Preferred Power Source)
- 500 kV Power Distribution
- 161 kV Preferred Power Source
- 6.9 kV Diesel Generators
- Mitigating Strategies Power
- 6.9 kV FLEX Diesel Generators Watts Bar Nuclear Plant - DG CT Extension l 5
Flex 6.9 kV DG Watts Bar Nuclear Plant - DG CT Extension l 6
6.9 kV Flex Diesel Generators Watts Bar Nuclear Plant - DG CT Extension l 7
Request for Additional Information (RAI) 1 Please provide the following information:
a) The estimated and actual time taken for all 6-year, 12-year and/or 18*-year maintenance activities at WBN Unit 1 (and 2) for each of the four DGs, other than the values provided in Table 2 of the LAR.
b) Explain why WBN needs up to 14 days for 6-year, 12-year and 18* year maintenance related activities compared to 7 days at other plants with similar DGs.
- As applicable if the 12-year overhaul frequency has been changed to 18 years Watts Bar Nuclear Plant - DG CT Extension l 8
TVA Response RAI 1 1A-A DG 1B-B DG 2A-A DG 2B-B DG 4 year 68 (4/07) 59 (4/07) 160 (4/07)* 72 (4/07) 6 year 89 (4/09) 96 (5/09) 88 (4/09) 99 (5/09)
- Included as the emergent generator replacement (E1-11)
- WBN Estimated 18 year Surveillance
- Plan to Consolidate Work (VLF Testing, Tank Cleaning)
Watts Bar Nuclear Plant - DG CT Extension l 9
RAI 2
In view of the shared systems for dual unit operation, if the WBN units are in Modes 1, 2, 3 and 4, TS LCO 3.8.1 requires four operable DGs. With one or more DGs in a train inoperable, TS 3.8.1 Condition B currently requires the inoperable DG(s) to be restored to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to avoid entering TS 3.8.1 Condition F, which requires a plant shutdown. If both units are at power and the inoperable DG(s) was not restored within the 72-hour CT, a dual-unit shutdown would be required.
Please clarify the following:
a) The LAR states that the completion time (CT) extension will allow sufficient time to perform planned (emphasis added) maintenance activities that cannot be performed within a 72-hour CT. Please confirm that the proposed CT extension time will be used for preplanned 6-year, 12-year/18-year maintenance activities ONLY; and for routine testing and maintenance activities, the extended CT will not be invoked.
b) The LAR also states that TVA anticipates (emphasis added) that the above planned maintenance activities will be performed with one or both units in Mode 4 or above. From a defense-in-depth perspective, clarify if the preplanned 6-year and 12/18-year maintenance activities on the DGs, one at a time, will be performed with the associated Unit in Mode 5 or Mode 6.
TVA Response a) TVA is evaluating limiting the proposed completion time to the pre-planned 6-yr and 18-yr maintenance and will provide our position in the formal response to this RAI b) TVA does plan to perform this maintenance with both Units in Modes 1 - 4.
Watts Bar Nuclear Plant - DG CT Extension l 10
RAI 3
Based on the information provided in Enclosure 2 of letter dated August 31, 1992 and the LAR Section 3.5 related to coping with Station Black Out:
Please clarify the following:
a) Please explain the sequence of events of a LOOP (both Units) when Unit 1 DG 1A-A (or 1B-B) is under maintenance, the redundant DG 1B-B (or 1A-A) fails to start (SBO Unit 1) and a Unit 2 DG has a single failure.
b) Please explain if the response is also applicable for SBO in Unit 2 and single failure of a DG in Unit 1.
c) According to the Watts Bar licensing basis, safe shutdown is considered as placing both units in a hot standby (Technical Specification MODE 3) condition and maintaining such a condition. However in view of proposed extended maintenance on one standby DG, BTP 8-8 recommends that the supplemental AC source, used to support extended CT, have the capacity and capability to bring the Unit to cold shutdown. Please confirm that one 6.9 kV FLEX DG coupled with one standby DG is adequate to place both units in cold shutdown and maintain cold shutdown conditions.
TVA Response a) TVA will provide the logic and sequence of events of a Loss of Offsite Power on both Units with a DG out of service for maintenance and a failure of the redundant DG to start.
b) The response is applicable to Unit 2 and will be provided in our response.
c) TVA will confirm that one 6.9 kV FLEX DG coupled with one standby DG is adequate to place both units in cold shutdown and maintain cold shutdown conditions.
Watts Bar Nuclear Plant - DG CT Extension l 11
RAI 4
Section 4.3 of Enclosure 1 of the LAR provides an assessment of DG completion time extension and has the following statements Each of the four DGs can supply one of the four separate Class 1E 6.9 kV shutdown boards. Each DG is started automatically on a LOOP or LOCA. The DG arrangement provides adequate capacity to supply the ESF and protection systems for the DBA, assuming the failure of a single active component in the system. Because the standby power systems can accommodate a single failure, extending the CT for an out-of-service DG has no impact on the system design basis. Safety analyses acceptance criteria as provided in the UFSAR are not impacted by the changes.
With the proposed 6.9 kV FLEX DG as a replacement for a DG under maintenance, please explain if the conclusion is applicable for all postulated events (coupled with single failure) that are considered in the licensing basis.
TVA Response TVA is evaluating the RAI however, it appears that the out of service DG coupled with an additional single failure (redundant DG) would result in a SBO on the affected Unit. The Watts Bar design basis is LOOP/LOCA and therefore the single failure would not be considered with the redundant DG out of service.
Watts Bar Nuclear Plant - DG CT Extension l 12
RAI 5
Considering a single failure of A train power after a dual unit LOOP, the B train power must be able to bring both units to cold shutdown to comply with BTP 8-8 and General Design Criteria (GDC)-5. Likewise, considering a single failure of B train power after a dual unit LOOP, the A train power must be able to bring both units to cold shutdown to comply with BTP 8-8 and GDC-5.
Based on analysis, demonstrate that the FLEX DG will perform its intended function of serving as the supplemental power source for an inoperable DG while satisfying the guidelines of BTP 8-8 and the requirements of GDC-5 in the following scenarios and for all the unit Mode combinations (1-4) allowed by the proposed TS changes:
a) The FLEX DG is substituting for a Train A EDG and a dual unit LOOP and dual unit cooldown with loss of emergency power Train B, such that both units are relying on Train A power. Please explain if the response is also applicable for SBO in Unit 2 and single failure of a DG in Unit 1.
b) The FLEX DG is substituting for a Train B EDG and a dual unit LOOP and dual unit cooldown with loss of emergency power Train A, such that both units are relying on Train B power.
c) In the above scenarios, identify which loads on the shutdown switchboard powered by the FLEX DG would not receive power because the FLEX DG cannot supply the same power capacity as the DG and explain why that would be satisfactory in each of the above scenarios.
d) In the above scenarios, discuss which ERCW pumps and CCS pumps are running and what heat exchange function each CCS heat exchanger is performing.
TVA Response TVA understands the question and will provide a response Watts Bar Nuclear Plant - DG CT Extension l 13
RAI 6
Please provide details of DG loadings for the scenarios considered in question 5 above. In view of the differences in DG loadings, please indicate which case is the limiting case.
Also, provide a time-line based on plant procedures, for connecting the proposed 6.9 kV FLEX DG to the associated safety-related bus/busses in the above scenarios.
TVA Response a) TVA will provide the DG loading details for each of the scenarios considered in RAI 5.
b) A time-line based on plant procedures for connecting the proposed 6.9kV Flex DG will also be provided.
Watts Bar Nuclear Plant - DG CT Extension l 14
NRC Draft RAI 7 Please clarify whether the FLEX DGs have been (or will be) tested to start and run loads that will be required for scenarios listed in Questions above.
TVA Response
- Post Installation Testing Phase Rotation Test Run and load test to test bank (100%)
- TVA performs the following testing of the FLEX DGs consistent with NEI-1206 A monthly inspection, Semi-annual inspection and start test, Annual inspection - run and load test (30% load to test bank),
Three Year Inspection - run and load test (100% load to test bank)
Watts Bar Nuclear Plant - DG CT Extension l 15
RAI 8
Transitioning to Phase 2 includes aligning and placing into service the pre-staged 480 V FLEX DGs and the 6.9 kV FLEX DGs.
Based on the information provided on the FLEX DGs, the Staff requests following additional information:
a) Please confirm whether the 480 V FLEX DGs are part of the proposed extension request for DGs and will have the same requirements for testing and availability checks as the 6.9 kV FLEX DGs.
b) Assuming that it takes the proposed TS allowed time of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to establish the availability of the 6.9 kV FLEX DG, please provide a time line, using current plant procedures, for connecting the proposed 6.9 kV FLEX DG and the 480 V FLEX DG (if required) to each of the associated safety busses if an unplanned DG maintenance was being conducted and a LOOP event is experienced.
c) For the event postulated in item b) above, please confirm if the Unit with DG undergoing maintenance will first enter SBO procedures if the associated DG fails to start.
TVA Response a) TVA does not consider the 480 v FLEX DG part of the proposed extension request.
b) TVA will provide a timeline supporting the 2-hour establishment of 6.9kV FLEX DG.
c) Upon lost of off-site and on-site power to the 6.9 kV shutdown boards the operator will enter ECA-0.0, Loss of All AC Watts Bar Nuclear Plant - DG CT Extension l 16
RAI 9
LCO 3.8.1 proposed Required Action (RA) B.2 uses the word evaluate when assessing the availability of 6.9 kV FLEX DG. However this wording apparently disagrees with the basis written for RA B.2 which states that it is necessary to verify that the availability of the FLEX DG. Per 10 CFR 50.36(a)(1) the basis is a summary statement or reasons for the specification. The proposed reasoning and basis used in the LAR is that the FLEX DG be available during the longer proposed CT for the standby DG.
Propose a reworded RA B.2 that agrees with the proposed basis.
TVA Response TVA will provide wording so that the Required Action and the bases agree.
Watts Bar Nuclear Plant - DG CT Extension l 17
RAI 10
While the proposed SR more closely matches that in NUREG-1431, Rev. 4, the wording in the NUREG is based on typical plant design where a single DG has the capacity and capability to supply all necessary accident and safe shutdown loads for the specific Unit. At Watts Bar both DGs of the same load group are necessary to supply all necessary accident and safe shutdown loads.
a) Explain how the proposed wording results in a SR that is equivalent in purpose to the existing SR.
b) In your answer address the question of whether both DGs of the same load group will be simultaneously started and loaded during surveillance testing at WB for SR 3.8.1.19 and if not why not?
c) Explain how both DGs of the same load group start if there is an accident and a LOOP event in one Unit only.
TVA Response a) The proposed wording is equivalent in the test to the existing SR. This SR does not require simultaneous starting of the same power train b) Each DG automatically starts on a loss of voltage on its respective shutdown board. A non-safety related common start circuit starts all DG once one is started but is not credited in any accident analysis.
c) See b) above.
Watts Bar Nuclear Plant - DG CT Extension l 18
RAI 11
Table 2 in Enclosure 1 of the LAR provides an overview of historical record of DG Maintenance Activity Completion Times (hours). The staff notes that very low frequency (VLF) cable testing has consistently taken longer than maintenance activities associated with the DGs. If future cable testing is projected to take longer than the 6-year or 18-year maintenance testing, please provide a listing of cables and associated equipment that render the respective DG to be inoperable and the corresponding estimated time for each cable testing.
TVA Response TVA has projected that the VLF cable testing in the future will not be limiting. The 6-year and 18-year maintenance testing will remain the schedule driver.
Watts Bar Nuclear Plant - DG CT Extension l 19
RAI 12
Section 3.12 Work Control and Scheduling of Enclosure 1 of the LAR provides the TVA method of risk assessment and work control. TS Bases Table 3.8.1-2 in Attachment 2 and 4 the LAR provides additional precautions that will be taken during the proposed extended CT for DG maintenance.
Please provide a succinct summary or listing of all compensatory actions (such as protected train concept, allowable entry and maintenance of offsite power system switchyard, elective maintenance activities, etc.) that have been considered and incorporated into procedures for extended DG outages.
TVA Response TVA will provide a succinct summary or listing of all compensatory actions that have been considered and incorporated into procedures for extended DG outages.
Watts Bar Nuclear Plant - DG CT Extension l 20
RAI 13
In general, the LAR refers to the 6.9 kV FLEX DGs as 3 MWe FLEX DG 6.9 kV FLEX Generators. Section 3.8 of the LAR states Each FLEX DG is a 6.9 kV, 3-phase, 60 Hz synchronous machine with a continuous rating of 4062.5 kilovolt-amp (kVA) at 0.8 power factor, from MTU Onsite Energy indicating that each DG has a continuous rating of 3.250 MW at 0.8 power factor. Please clarify the rating of the FLEX DGs and output power available from each DG to support safe shutdown of the Unit(s).
TVA Response TVA will clarify the rating (3.25 megawatt) of the FLEX DGs and the output power available from each DG to support safe shutdown of the Unit(s).
Watts Bar Nuclear Plant - DG CT Extension l 21
Closing Remarks Watts Bar Nuclear Plant - DG CT Extension l 22