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Prairie Island Nuclear Generating Plant Meeting February 19, 2014
Diesel Generator Steady State Voltage and Frequency LimitsDiesel Generator Steady State Voltage and Frequency Limits
2
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
3
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
4
Meeting Purpose
� Establish dialog on this LAR
� Applicability of industry initiative (WCAP-17308)
� Proposed EDG SR changes
� Basis for changes
5
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
6
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
7
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
8
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
9
LAR Scope
� EDG operating voltage
� EDG operating frequency
� Impact on supplied loads
� Impact on EDGs
� AL 98-10 submittal
10
Proposed TS and Bases Changes
� SS Voltage lower and upper limits
� SS Frequency lower and upper limits
� TS Bases changes
11
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
12
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
13
Proposed TS and Bases Changes (continued)
� TS Bases Revisions:
�Define “steady state”
�Clarify purpose of steady state voltage requirement
14
15
Technical Bases for Changes
� Lower voltage limit
� 4084 VAC
� Within nominal rating of equipment
� Protective relaying calculations
16
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
17
Technical Bases for Changes(continued)
� Upper voltage limit
� 4400 VAC
� Equipment ratings within nominal
� Protective relaying
18
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
19
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
20
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
21
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
22
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
23
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
24
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
25
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
26
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
27
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
28
Schedule
� LAR drafted
� Validation in progress
� Adjust for meeting input
� Plan to submit soon after addressing meeting input
29
Conclusion
� Discussion
� Questions
� Closing statements
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