Prairie Island Nuclear Generating Plant Meeting February 19, 2014 Diesel Generator Steady State Voltage and Frequency Limits Diesel Generator Steady State Voltage and Frequency Limits
Prairie Island Nuclear Generating Plant Meeting February 19, 2014
Diesel Generator Steady State Voltage and Frequency LimitsDiesel Generator Steady State Voltage and Frequency Limits
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Agenda
� Introductions Vincent
� Meeting purpose Davison
� Background Vincent
� Applicability of industry initiatives Mathew
� LAR scope Vincent
� Proposed TS and Bases changes Vincent
� Technical basis for changes Zamarripa
� Schedule Mathew
� Conclusion Davison
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Xcel participants
� Kevin Davison – Site Vice President
� Marty Murphy – Director Regulatory Affairs
� Joe Mathew – Design Engineering Manager
� Paul Zamarripa – Engineering Supervisor
� Dale Vincent – Regulatory Affairs Project Manager
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Meeting Purpose
� Establish dialog on this LAR
� Applicability of industry initiative (WCAP-17308)
� Proposed EDG SR changes
� Basis for changes
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Background
� EDG Frequency identified in CAP – 2006
�AL 98-10 compensatory measures
� EDG Voltage identified in IN – 2007-09
�AL 98-10 compensatory measures
� Meeting with NRC - June 2008
� PWROG adopt issue – 2009
� PWROG meeting with NRC – 2010
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Background(continued)
� EDG Exigent LAR - October 2010
� PWROG meeting with NRC – 2011
� NRC Frequency submittal finding – 2011
� EDG Voltage LAR – May 2012
� EDG Voltage limits revised – 2013
�AL 98-10 compensatory measures revised
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Applicability of Industry Initiatives
� WCAP-17308 methodology
�SRs verify EDG operate at nominal voltage and frequency
�Variation from nominal treated as uncertainty
�Minimal impact on supplied loads and EDGs
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Applicability of Industry Initiatives (continued)
� How does PINGP LAR align ?
�Assumes EDG operates at range extremes
�Significant impact on supplied loads
�Significant impact on EDGs
� PINGP LAR will not incorporate WCAP-17308
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LAR Scope
� EDG operating voltage
� EDG operating frequency
� Impact on supplied loads
� Impact on EDGs
� AL 98-10 submittal
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Proposed TS and Bases Changes
� SS Voltage lower and upper limits
� SS Frequency lower and upper limits
� TS Bases changes
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Proposed TS and Bases Changes (continued)
� Current TS
�SS Voltage lower voltage: 3740 VAC
�SS Voltage upper voltage: 4580 VAC
�SS Frequency lower limit: 58.8 Hz
�SS Frequency upper limit: 61.2 Hz
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Proposed TS and Bases Changes (continued)
� Proposed TS
�SS Voltage lower voltage: 4084 VAC
�SS Voltage upper voltage: 4400 VAC
�SS Frequency lower limit: 59.5 Hz
�SS Frequency upper limit: 60.5 Hz
Proposed TS and Bases Changes (continued)
� TS Revisions:
�SR 3.8.1.2 – monthly test
�SR 3.8.1.6 – 6-month fast start test
�SR 3.8.1.9 – 2-year 24-hour run test
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Proposed TS and Bases Changes (continued)
� TS Bases Revisions:
�Define “steady state”
�Clarify purpose of steady state voltage requirement
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Technical Bases for Changes
� Lower voltage limit
� 4084 VAC
� Within nominal rating of equipment
� Protective relaying calculations
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Technical Bases for Changes
� Lower voltage limit (continued)
� Degraded voltage setpoint basis
� Ready to load relay @ V-Hz permissive bkr closure
� PLC sequencing requires bus voltage > DV R/S [4027]
� Lower limit > DVR setting + error + R/S > 96.8% [4027]
� DV LL >94.5% used in DV calculation
� Exceeds the region of degraded voltage
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Technical Bases for Changes(continued)
� Upper voltage limit
� 4400 VAC
� Equipment ratings within nominal
� Protective relaying
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Technical Bases for Changes(continued)
� ESF pump motor performance with proposed V&F limits
� Motor terminal voltage affected
� With 4084 VAC pumps operate within specification
� Bus voltage remains above degraded voltage setpoint
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Technical Bases for Changes(continued)
� ESF pump motor performance with proposed V&F limits (continued)
� Frequency affects governed by affinity laws
� Pump speed (S) proportional to frequency (F)
� Discharge pressure proportional to pump speed squared (S2)
� Re-performed thermal hydraulic analyses
� +0.5 Hz – pumps not in run-out, flow rate not excessive
� -0.5 Hz – Necessary flow rates attained
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Technical Bases for Changes(continued)
� ESF Ventilation performance with proposed V&F limits
� Evaluations performed
� Auxiliary Building Special Ventilation (ABSVS)
� Shield Building Ventilation (SBVS)
� Containment ventilation
� EDG Rooms
� Control Room Ventilation
� Safeguards Screenhouse Ventilation
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Technical Bases for Changes(continued)
� MOV performance with proposed V&F limits
� MOV motor terminal voltage affected
� Apply degraded voltage
� Adequate torque
� MOVs will operate at lower voltage limit
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Technical Bases for Changes(continued)
� MOV performance with proposed V&F limits (continued)
� MOV frequency effects (continued)
� Analyses assumption +1.2 Hz
� Upper frequency
� Increase dP 4%
� Acceptable results
� Lower frequency
� Travel speed
� Actuation time
� Adequate margin
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Technical Bases for Changes(continued)
� Relay coordination and interface with TS 3.3.4 with proposed V&F limits
� Calculations performed across 75% - 110% of nominal 4kV motor rating
� Modeled in ETAP
� Coordination acceptable
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Technical Bases for Changes(continued)
� EDG loading with proposed V&F limits
� Unit 1 EDG Design Loading
� Licensed under AEC SG 9 paragraph C2 guidance
� 2000 Hr rating or 90% of 30 Min rating (3250 kW)
� Limit of 2750 kW
� Unit 2 EDG Design Loading
� Licensed under RG 1.9 Rev 2 paragraph C2 guidance
� Predicted load < short-time rating
� Limit of 5400 kW
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Technical Bases for Changes(continued)
� EDG loading with proposed V&F limits
� Evaluated loads for LOOP+SI
� Frequency 60.5 Hz
� Applied affinity laws to inductive loads
� All EDG adequately sized
� D2 (Unit 1 Train B) least margin
� 2335 kW load vs. 2750 kW rating
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Technical Bases for Changes(continued)
� EDG loading with proposed V&F limits
� Evaluated loads for SBO
� 10CFR 50.63 and RG 1.155
� Frequency 60.5 Hz
� Applied affinity laws
� All EDG adequately sized
� D1 (Unit 1 Train A) least margin
� 2560 kW load vs. 2750 kW rating
� Unit 2 EDGs much more margin
� Rated 5400 kW
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Technical Bases for Changes(continued)
� EDG loading with proposed V&F limits (continued)
� Minimum fuel oil capacity evaluated
� Calculations revised
� Values in TS Bases per LA
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Schedule
� LAR drafted
� Validation in progress
� Adjust for meeting input
� Plan to submit soon after addressing meeting input
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Conclusion
� Discussion
� Questions
� Closing statements