ML17034A332
| ML17034A332 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 02/03/2017 |
| From: | Doyle G Tennessee Valley Authority |
| To: | Office of Nuclear Reactor Regulation |
| Saba F DORL/LPL2-2 301-415-1447 | |
| References | |
| Download: ML17034A332 (32) | |
Text
Browns Ferry Nuclear Plant Extended Power Uprate License Amendment Request Transmission System Update Supplements NRC Public Meeting Gerry Doyle Director EPU February 15, 2017
BFN EPU Transmission System Update Supplements - Agenda Browns Ferry EPU Transmission System Update Supplements
Introductions
Background Supplement 36, Transmission System Updates
- Safety Aspects Discussion of Changes Summary of Impacts Questions Supplement 37, Transmission System Updates
- Environmental Aspects Discussion of Changes Summary of Impacts Questions Questions/Comments G Doyle A Michael P Donahue D Green G Doyle l 2
BFN EPU Transmission System Update Supplements - Introductions Gerry Doyle - Director, EPU Pete Donahue - EPU Engineering Manager Dan Green - EPU Licensing Manager Bill Baker - EPU Operations Support Manager Ashley Michael - EPU Project Manager Joe Bashore - EPU Engineer Gordon Williams - Corporate Licensing Project Manager Browns Ferry EPU Transmission System Update Supplements l 3
BFN EPU Transmission System Update Supplements - Background
Extended Power Uprate (EPU) License Amendment Request (LAR)
Supplement 18
Interconnection System Impact Study (SIS), performed for Browns Ferry Nuclear Plant (BFN) at EPU conditions, determined that main generator stability issues exist for a three-phase fault on one of several BFN transmission lines coincident with certain transmission lines already out of service (N-1-1 event)
Existing generator excitation system could not raise field voltage fast enough and high enough to prevent main generator from becoming unstable
To address transient stability issue during N-1-1 event, BFN planned to install a new shunt-fed, static excitation system on each of the three BFN units New excitation system would provide field current directly to brushes and collector rings eliminating need for rotating Alterrex exciter and stationary diodes
Additional computer simulations for interconnection SIS, with this new excitation system modeled, demonstrated main generators remain stable during N-1-1 event Browns Ferry EPU Transmission System Update Supplements l 4
BFN EPU Transmission System Update Supplements - Background
Legacy error in generator field parameters used in development of Interconnection SIS was identified
Generator field parameter values provided after stator rewind in 2003
Condition entered into Tennessee Valley Authority (TVA) Corrective Action Program
Stability studies, at EPU power levels, with new generator field parameter values indicate more extensive compensatory measure needed for main generators to remain stable during N-1-1 event As a result, previous N-1-1 event stability mitigation plan (addressed in BFN EPU LAR Supplement 18) no longer viable At EPU power levels, these more extensive compensatory measures would require BFN units, even with proposed static excitation systems installed, to be de-rated, whenever an applicable transmission line, as specified in Interconnection SIS, was taken out of service Browns Ferry EPU Transmission System Update Supplements l 5
BFN EPU Transmission System Update Supplements - Background
Previous N-1-1 Event Stability Mitigation Plan
Static exciter installed on each of the three BFN units Shunt-fed, static excitation would provide field current directly to brushes and collector rings eliminating need for rotating Alterrex exciter and stationary diodes
Updated N-1-1 Event Stability Mitigation Plan
For each BFN units generator, the following will be performed Automatic voltage regulator will be modified Alterrex system will be modified to be self-excited, with a shaft driven alternator Static exciter will not be installed
Static Volt-Ampere Reactive (VAR) Compensator sized at +450 Mega Volt-Ampere Reactive (MVAR)/-400 MVAR will be installed at existing Limestone Substation (near BFN)
Combination of Static VAR Compensator and four Capacitor Banks will provide a minimum reactive compensation of 764 MVAR Capacitor Banks at Wilson Substation will not be installed Browns Ferry EPU Transmission System Update Supplements l 6
BFN EPU Transmission System Update Supplement 36 - Safety Aspects Browns Ferry EPU Transmission System Update Supplements l 7
LAR Supplement 36 - Safety Aspects (submitted 1/20/17) - Interconnection System Impact Study, Revision 3 Discussion of Changes Updated, for each unit at EPU conditions, to include
Total Gross Capacity and New Net Expected Capacity for Summer, Winter, Spring/Fall Updated cost estimate for replacement of breaker failure relays Updated to reflect new proposed N-1-1 Event Stability Mitigation Plan Summary of Impacts Additional computer simulations of the N-1-1 event for Interconnection SIS, with the modified excitation system and the new Static VAR Compensator modeled, have shown that the main generators remain stable Questions
BFN EPU Transmission System Update Supplement 36 - Safety Aspects Browns Ferry EPU Transmission System Update Supplements l 8 - LAR Attachment 43, Transmission Stability Study (TSS), Revision 4 Discussion of Changes Updated to reflect new proposed N-1-1 Event Stability Mitigation Plan Summary of Impacts Simulations of TSS events were performed with static VAR compensator modeled at Limestone Substation to evaluate the effect of the proposed transmission system upgrade on the TSS results
Static VAR compensator improves TSS results for 500 kilovolt (kV) and 161 kV offsite power systems Questions
BFN EPU Transmission System Update Supplement 36 - Safety Aspects Browns Ferry EPU Transmission System Update Supplements l 9 /4 - Nuclear Regulatory Commission (NRC) Request for Additional Information (RAI) EEEB-RAI 1 Response, Revision 2 Discussion of Changes Updated to reflect new proposed N-1-1 Event Stability Mitigation Plan Summary of Impacts Static VAR Compensator significantly improves 500 kV offsite power system Most critical line unchanged from previous EEEB-RAI 1 Response Acceptance criteria continue to be satisfied 161 kV offsite power system also benefits from Static VAR Compensator
However, due to Static VAR Compensators location on 500 kV offsite power system, the benefit to 161 kV offsite power system is not as significant as the benefit to 500 kV offsite power system Questions
BFN EPU Transmission System Update Supplement 36 - Safety Aspects Browns Ferry EPU Transmission System Update Supplements l 10 - LAR Attachment 44, Probabilistic Risk Assessment (PRA) Addendum (Revised)
Discussion of Changes Impact of proposed exciter modification addressed
Existing Automatic Voltage Regulator (AVR) is being modified
Also includes modifying AVR to receive power from the exciter generator (self-excited) instead of an external power source (separately excited)
Reliability of proposed modified exciter can be compared with existing exciter to provide insights into expected change in equipment reliability
Significant difference between existing and proposed exciter systems is power supply arrangement for AVR Current system uses external power supplied from redundant excitation transformers, while modified system will obtain power from output of exciter generator through redundant transformers Removal of external power source reduces number of potential component failures which could lead to a consequential generator exciter failure that would result in a turbine trip With proposed modification, AVR will receive power from exciter stator, which is already required for exciter to function Modification to AVR itself is not expected to impact reliability of exciter
BFN EPU Transmission System Update Supplement 36 - Safety Aspects Browns Ferry EPU Transmission System Update Supplements l 11 - LAR Attachment 44, PRA Addendum (Revised)
(continued)
Summary of Impacts Proposed modification to generator excitation system does not result in a baseline risk increase nor a change in risk from Current Licensed Thermal Power to EPU power Modified generator excitation system is considered to be more reliable than current generator excitation system Questions
BFN EPU Transmission System Update Supplement 36 - Safety Aspects Browns Ferry EPU Transmission System Update Supplements l 12 - Power Uprate Safety Analysis Report Section 2.5.1.2.2 Update Discussion of Changes Updated to reflect new proposed N-1-1 Event Stability Mitigation Plan Summary of Impacts Additional computer simulations of N-1-1 event for Interconnection SIS, with modified excitation system and the new Static VAR Compensator modeled, have shown that the main generators remain stable Questions
BFN EPU Transmission System Update Supplement 36 - Safety Aspects Browns Ferry EPU Transmission System Update Supplements l 13 - LAR Attachment 47, List and Status of Modifications, Revision 4 Discussion of Changes Static exciters will not be installed
For each BFN units main generator, the following will be performed AVR will be modified Alterrex system will be modified to be self-excited, with a shaft driven alternator
Modifications to be implemented as follows Unit 1 - Fall 2020 Unit 2 - Spring 2021 Unit 3 - Spring 2020 Summary of Impacts Generator exciters modified to be consistent with Interconnection SIS and TSS Questions
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 14 LAR Supplement 37 - Environmental Aspects (submitted 2/3/17) - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 Updated Response to RERP-GE-RAI 2 Discussion of Changes
Updated to reflect new proposed N-1-1 Event Stability Mitigation Plan Wilson Substation deleted from environmental reviews
Environmental reviews and results are included in Attachment 1, except for Limestone Substation
Deleted previous Attachment 2, letter to Tennessee State Historic Preservation Office with Phase 1 Wilson Substation Cultural Resources Survey
New Attachment 2 includes Supplemental Environmental Information for Limestone Substation Static VAR Compensator Construction
Updated schedule for completion of modifications
Updated to include Attachment 4, letter to Alabama State Historic Preservation Office with Phase 1 Limestone Substation Cultural Resources Survey Summary of Impacts
Addressed in Attachment 2 Questions
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 15 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 1, Supplemental Environmental Information for Transmission System and BFN Main Generator Upgrades (excluding Limestone Substation)
Discussion of Changes
Updated to reflect new proposed N-1-1 Event Stability Mitigation Plan
Environmental reviews and results included, except for Limestone Substation
Added reference to new Attachment 2 for Supplemental Environmental Information for Limestone Substation Static VAR Compensator Construction
Information related to environmental reviews for Wilson Substation deleted New proposed N-1-1 Event Stability Mitigation Plan does not involve changes to Wilson Substation Summary of Impacts
Review results/conclusions unchanged Review did not identify moderate or large environmental impacts from installation of proposed upgrades TVA anticipates that installation of proposed upgrades will not affect human health or environment Questions
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 16 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 2, Supplemental Environmental Information for Limestone Substation Static VAR Compensator Construction Discussion of Changes
Supplemental Environmental Information addresses the same topics as included in
Overview of Operations and Equipment Changes - Static VAR Compensator proposed to be installed at Limestone Substation Requires expansion (approximately 25 acres of previously disturbed TVA property) of existing substation footprint with additional grading and clearing
Cost Benefit Analysis included in Attachment 1 Economic benefit is still highly positive
Phase 1 Cultural Resources Survey completed and results submitted to Alabama State Historic Preservation Office for concurrence (included in Attachment 4)
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 17 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 2, Supplemental Environmental Information for Limestone Substation Static VAR Compensator Construction Discussion of Changes
Public drinking water is available to residents in the area, however, private wells are also used for drinking water Mitigation measures include Erosion control Best Management Practices (BMPs)
Use of fertilizers and herbicides in areas that flow to springs would be avoided or would be used sparingly
Endangered, Threatened, or Special Status Species - Aquatic TVA Natural Heritage Database query identified 21 federally listed aquatic species within Limestone Creek Watershed Field survey documented no intermittent or perennial streams and three wet weather conveyances (ephemeral streams)
Three ephemeral streams contain no suitable habitat for federally listed species To eliminate potential impacts to sensitive aquatic life, ground disturbance will be minimized and all work conducted in accordance with BMPs
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 18 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 2, Supplemental Environmental Information for Limestone Substation Static VAR Compensator Construction Discussion of Changes
Endangered, Threatened, or Special Status Species - Terrestrial (Botany)
Field survey documented no impact to federally listed plant species or designated critical habitat Neither exist within area that would be affected by proposed work Field survey documented no rare plants or habitat capable of supporting state listed plant species occurs in the project area
Endangered, Threatened, or Special Status Species - Terrestrial (Zoology)
TVA Natural Heritage Database query indicated no state or federally listed species within three miles of project area One federally protected species (bald eagle) and two federally listed species (gray bat and Indiana bat) are known from Limestone County, Alabama United States Fish and Wildlife Service has determined that federally listed northern long-eared bat may occur in Limestone County, Alabama
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 19 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 2, Supplemental Environmental Information for Limestone Substation Static VAR Compensator Construction Discussion of Changes
Endangered, Threatened, or Special Status Species - Terrestrial (Zoology)
For the bald eagle No suitable nesting or foraging habitat exists within project area Bald eagle records are known approximately 9 to 17.5 miles from project footprint No additional nests or individuals are known from project area and none observed during January 2017 field survey when active nesting behavior would have been apparent No waterways or wetlands are present or would be affected by the proposed actions, thus bald eagle habitat not impacted
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 20 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 2, Supplemental Environmental Information for Limestone Substation Static VAR Compensator Construction Discussion of Changes
Endangered, Threatened, or Special Status Species - Terrestrial (Zoology)
For the gray, Indiana, and northern long-eared bats No caves or other winter hibernacula exist in project footprint or would be impacted by proposed action During January 2017 surveys, no suitable roost trees were identified within the forested habitat of area to be cleared No wetlands or waterways are present within the proposed action area, thus foraging habitat for these bat species would not be affected
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 21 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 2, Supplemental Environmental Information for Limestone Substation Static VAR Compensator Construction Discussion of Changes
Review results for the following areas are the same as for other substation expansions Socioeconomic and Environmental Justice Considerations Land Use, Wetlands, and Natural Areas Transmission Facilities, Electric Shock, and Electromagnetic Fields Noise, Odor, Microbiological, and Visual Aesthetics Air Impacts Terrestrial Biota and Habitat Non-radiological Waste Streams and Potential for Pollutant Generation Geological Environment Aquatic Resources - Rivers, Streams, and Reservoirs Groundwater Surface Water Compliance, Permits, and Reporting
Applicable TVA BMPs and Environmental Quality Protection Specifications summarized
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 22 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 2, Supplemental Environmental Information for Limestone Substation Static VAR Compensator Construction Summary of Impacts
Environmental review for Static VAR Compensator installation at Limestone substation did not identify moderate or large environmental impacts from installation of the Static VAR Compensator
TVA anticipates that installation of proposed Static VAR Compensator will not affect human health or environment Questions
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 23 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 3, TVA letter to the Mississippi State Historic Preservation Office - TVA, Corinth and Holly Springs Substation Expansion Project, Phase 1 Cultural Resources Survey, Alcorn and Marshall Counties, Mississippi Discussion of Changes
No changes Summary of Impacts
No changes Questions
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 24 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 4, TVA letter to the Alabama State Historic Preservation Office - TVA, Limestone Substation Static VAR Compensator Construction, Phase 1 Cultural Resources Survey, Limestone County, Alabama Discussion of Changes
Documents results of Phase 1 Cultural Resources Survey and seeks Alabama State Historic Preservation Office concurrence with TVA findings No new archaeological resources were documented within boundaries of the Area of Potential Effects One farm complex was located within line of sight of project area Includes four cinderblock residential houses, one cinderblock outbuilding, as well as several other wood and metal outbuildings.
Construction dates of complex structures range from 1944 to 1970 Property not identified as having been associated with any important event,or significant people, nor does it display distinct characteristics of a type, period, or method of construction
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 25 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 2, Attachment 4, TVA letter to the Alabama State Historic Preservation Office - TVA, Limestone Substation Static VAR Compensator Construction, Phase 1 Cultural Resources Survey, Limestone County, Alabama Summary of Impacts
Based on results of Phase 1 Cultural Resources Survey and pending agreement by the Alabama State Historic Preservation Office, TVA finds that no historic properties listed or eligible for listing in the National Register of Historic Places would be affected by the proposed construction Questions
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 26 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 3 Discussion of Changes
Updated to reflect new proposed N-1-1 Event Stability Mitigation Plan
Added Static VAR Compensator at Limestone Substation
Deleted Wilson Substation
Updated schedule for completion of modifications Summary of Impacts
EPU schedule not impacted by changes Questions
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 27 - Updated Responses to NRC RAIs RERP-GE-RAI 2, RERP-GE-RAI 3, and RERP-GE-RAI 4 (continued)
Updated Response to RERP-GE-RAI 4 Discussion of Changes
Updated to reflect new proposed N-1-1 Event Stability Mitigation Plan
Added Static VAR Compensator at Limestone Substation
Deleted Wilson Substation
Updated environmental review closure status/dates Summary of Impacts
Addressed in new Attachment 2 of revised response to RERP-GE-RAI 2 Questions
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 28 - Supplemental Environmental Report, Revision 2 Discussion of Changes Updated to reflect new proposed N-1-1 Event Stability Mitigation Plan
1.0 Executive Summary Reactive compensation
2.2 Related Power Uprate Submittals and NEPA Documentation Main generator excitation system modifications
4.0 Overview of Operational and Equipment Changes Reactive compensation
6.0 Cost Benefit Analysis Updated cost of new proposed N-1-1 Event Stability Mitigation Plan
7.1.1 BFN Site and Surroundings Static VAR Compensator at Limestone Substation Capacitor Bank installation at four locations distant from BFN
7.1.2 Transmission Facilities Static VAR Compensator at Limestone Substation, requiring expansion of existing footprint Four capacitor banks locations Main generator excitation system modifications
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 29 - Supplemental Environmental Report, Revision 2 Discussion of Changes (continued)
Corrected typographical/mathematical errors
In Table 7.2-3 Summary of BFN Hydrothermal Impacts for Warm, Summer Meteorology, in column Change 105%120% OLTP Diffuser Discharge Temperature, Flow-Weighted hr Avg Max Hydrothermal Derate Operation - Max No. Hours of Derate for Summers with Derate Summary of Impacts Addressed in new Attachment 2 of revised response to RERP-GE-RAI 2 Questions
BFN EPU Transmission System Update Supplement 37 - Environmental Aspects Browns Ferry EPU Transmission System Update Supplements l 30 - Draft Environmental Assessment and Finding of No Significant Impact Change Markup Discussion of Changes Markup of proposed changes provided to reflect environmental review of modifications associated with new proposed N-1-1 Event Stability Mitigation Plan
Used information from revised Attachment 1, new Attachment 2, and new Attachment 4 of updated response to RERP-GE-RAI 2 Summary of Impacts Based on information provided, it is expected that NRC will be able to update the draft Environmental Assessment and Finding of No Significant Impact and conclude that the proposed action, including changes associated with the proposed Transmission System update, would not have significant effects on quality of human environment Questions
BFN EPU Transmission System Update Supplements - Acronym List Browns Ferry EPU Transmission System Update Supplements l 31 AVR - Automatic Voltage Regulator BFN - Browns Ferry Nuclear Plant BMP - Best Management Practice EPU - Extended Power Uprate kV - kilovolt LAR - License Amendment Request MVAR - Mega Volt-Ampere Reactive NRC - Nuclear Regulatory Commission PRA - Probabilistic Risk Assessment RAI - Request for Additional Information SIS - System Impact Study TSS - Transmission Stability Study TVA - Tennessee Valley Authority VAR - Volt-Ampere Reactive
BFN EPU Transmission System Update Supplements - Questions/Comments Browns Ferry EPU Transmission System Update Supplements l 32