ML14058A173

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Diesel Generator Steady State Voltage and Frequency Limits - Prairie Island Nuclear Generating Plant Meeting February 19, 2014
ML14058A173
Person / Time
Site: Prairie Island  Xcel Energy icon.png
Issue date: 02/19/2014
From:
Xcel Energy
To:
Division of Operating Reactor Licensing
Wall S
Shared Package
ML14057A374 List:
References
TAC MF3275, TAC MF3276
Download: ML14058A173 (30)


Text

Diesel Generator Steady State Voltage and Frequency Limits Prairie Island Nuclear Generating Plant Meeting February 19, 2014

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 2

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 3

Meeting Purpose

 Establish dialog on this LAR

 Applicability of industry initiative (WCAP-17308)

 Proposed EDG SR changes

 Basis for changes 4

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 5

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 6

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 7

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 8

LAR Scope

 EDG operating voltage

 EDG operating frequency

 Impact on supplied loads

 Impact on EDGs

 AL 98-10 submittal 9

Proposed TS and Bases Changes

 SS Voltage lower and upper limits

 SS Frequency lower and upper limits

 TS Bases changes 10

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 11

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 12

Proposed TS and Bases Changes (continued)

 TS Revisions:

 SR 3.8.1.2 - monthly test

 SR 3.8.1.6 month fast start test

 SR 3.8.1.9 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

Technical Bases for Changes

 Lower voltage limit

 4084 VAC

 Within nominal rating of equipment

 Protective relaying calculations 15

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 16

Technical Bases for Changes (continued)

 Upper voltage limit

 4400 VAC

 Equipment ratings within nominal

 Protective relaying 17

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 18

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 19

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 20

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 21

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 22

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 23

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 24

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 25

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 26

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 27

Schedule

 LAR drafted

 Validation in progress

 Adjust for meeting input

 Plan to submit soon after addressing meeting input 28

Conclusion

 Discussion

 Questions

 Closing statements 29