ML103330446
| ML103330446 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 12/14/2010 |
| From: | Beltz T Plant Licensing Branch III |
| To: | |
| beltz T, NRR/DORL/LPL3-1, 301-415-3049 | |
| References | |
| TAC ME1044, TAC ME1045, TAC ME1081, TAC ME1082 | |
| Download: ML103330446 (26) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 14, 2010 LICENSEE:
NextEra Energy Point Beach, LLC FACILITY:
Point Beach Nuclear Plant, Units 1 and 2 SUB~IECT:
SUMMARY
OF OCTOBER 27,2010, MEETING WITH NEXTERA ENERGY POII\\IT BEACH, LLC, TO DISCUSS ISSUES RELATED TO THE NRC STAFF REVIEW OF THE LICENSE AMENDMENT REQUESTS ASSOCIATED WITH AUXILIARY FEEDWATER, ALTERNATE SOURCE TERM, AND EXTENDED POWER UPRATE (TAC NOS. ME1081, ME1082, ME1044, ME1045)
On October 27,2010, a Category 1 public meeting was held between staff from the U.S.
Nuclear Regulatory Commission (NRC) and representatives of NextEra Energy Point Beach, LLC, at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland.
The purpose of the meeting was to discuss issues related to the Auxiliary Feedwater (AFW),
Alternate Source Term (AST), and Extended Power Uprate (EPU) amendments currently under review by the NRC staff.
A list of attendees is attached as Enclosure 1. The licensee's presentation is provided as. The licensee indicated that the information provided in the presentation could be made publicly available.
Discussion The licensee commenced its presentation by stating that the primary focus of the meeting was to resolve NRC staff concerns and solicit feedback on issues associated with the subject amendment requests. Specifically, the focus of the meeting was the emergency diesel generator (EDG) transient analysis and the impact on motor-operated valves (MOVs).
The initial focus of the discussion was associated with the EDG transient analysis. The NRC staff in the Electrical Engineering Branch (EEEB) of the Office of Nuclear Reactor Regulation determined that the primary focus of the meeting should be to address the transient response effects on the 1VI0Vs. As such, a significant amount of the meeting time was spent discussing the EDG transient analysis and the overall impact on the MOVs. The licensee appeared to address most of the NRC staff concerns related to the stroke time margins and valve stall concerns.
The following additional questions were developed as a result of the meeting:
- 1. In response to EEEB request for additional information (RAI) 1.a, transmitted via email dated May 19, 2010 (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML101410232), NextEra presented the results of the "A" EDG transient voltage analysis performed utilizing the ETAp dynamic model in NextEra letter dated August 9,2010 (ADAMS Accession No. ML102220146).
- 2 The NRC staff requested that the licensee provide the basis for the large pump motor loads utilized in the ETAp dynamic model. Specifically, to indicate if the large horsepower motors used in the model are conservative considering that initial pump flow rates may be higher than steady state flows due to the lower system resistance seen by the pump while piping fills with water.
- 2. During the meeting on October 27, 2010, NextEra indicated that the EDG output frequency is set monthly and assumed to be +/-.3 Hz.
The NRC staff requested that the licensee provide details of the calibration and loop accuracies for the EDG frequency loop and calculated loop uncertainties.
- 3. In response to EEEB RAI C transmitted via email dated September 16,2010 (ADAMS Accession No. ML102600388), NextEra provided additional details regarding the evaluation for heating effect on the thermal protective devices in NextEra letter dated September 28, 2010 (ADAMS Accession No. ML102710364).
The NRC staff requested that the licensee correct the response to RAI C.1, Part 2, to address Limitorque 92-01 Maintenance Update.
- 4. In response to EEEB RAls I, J, and K, transmitted via e-mail on September 16, 2010 (ADAMS Accession No. ML102600388), NextEra provided additional details regarding the evaluation for the limiting MOV in NextEra letter dated September 28, 2010 (ADAMS Accession No. ML102710364).
The NRC staff requested that the licensee clarify the stroke time margin of the limiting valve. NextEra letter dated September 28, 2010 indicated a stroke time margin of 3.47 seconds for the limiting valve versus a margin of 0.77 seconds provided in previous correspondence. The staff also requested that the licensee identify any additional margins (i.e., hydraulic margin-specifically valve opening margin to achieve flow and piping fill time, etc.) not included in the 3.47 second margin.
- 5. In response to EEEB RAI H, transmitted via e-mail dated September 16, 2010 (ADAMS Accession No. ML102600388), NextEra indicated that some MOVs experience voltages lower than their minimum evaluated, described as an MOV stall in NextEra letter dated September 28,2010 (ADAMS Accession No. ML102710364).
The NRC staff requested that the licensee confirm that either the MOVs will complete their full stroke prior to stall, or that the MOV stall events occur sufficiently far along in the MOV stroke such that the MOV has sufficient excess torque capability to complete its stroke once voltage is restored. Additionally, if an MOV is predicted to stall prior to the contactor dropping out, confirm that the MOV motors will not be damaged or that no significant stall time exists prior to the contactor dropping out.
Question 2 was added based on NRC staff feedback from a November 5, 2010, discussion.
The NRC staff confirmed with the licensee that the proposed questions adequately reflected their concerns. The licensee informed the NRC staff that it would respond to the questions no later than November 12, 2010.
- 3 The licensee agreed to supplement its application with two additional license conditions to support proposed modifications, as described below:
(1) Modifications will be implemented by the end of the spring 2011 Unit 2 refueling outage to ensure the motor-driven auxiliary feedwater and the turbine-driven auxiliary feedwater pump systems on each unit are powered from independent direct current power sources.
(2) Modifications will be implemented by the end of the spring 2011 Unit 2 refueling outage to reduce EDG loading such that the maximum loading will not exceed the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of the EDGs.
There were no members of the public in attendance. Public Meeting Feedback forms were not received.
Please direct any inquiries to me at 301-415-3049, or Terry.Beltz@nrc.gov.
~
~ry A. Beltz, Senior Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-266 and 50-301
Enclosures:
- 1. List of Attendees
- 2. Slide Presentation Handout Provided by the Licensee cc w/encls: Distribution via Listserv
LIST OF ATTENDEES OCTOBER 27,2010, MEETING WITH NEXTERA ENERGY POINT BEACH, LLC TO DISCUSS STATUS OF NRC STAFF REVIEWS RELATED TO THE AST, AFW, AND EPU AMENDMENTS FOR THE POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 NRC Roy Mathew Terry Beltz Bob Wolfgang Michael Farnan Thomas Scarbrough G. Singh Matharu John Janovich (Region III)
Xcel Energy (Prairie Island)
Sam Chesnutt NextEra Energy Liz Abbott Steve Hale Jeff Roberts Dan Tomaszewski Timothy Lensmire Chuck Richardson MPR Associates David Harris Bob DeWeese Meeting Handout
EDG Transient Analysis for AST, AFW and EPU Modifications October 27, 2010
Agenda
- Introduction
- Overview
- Emergency Diesel Generator (EDG) Transient Analysis
- Motor Operated Valve (MOV) Impact
- Conclusions 2
Agenda
- Introduction q. Overview
- Emergency Diesel Generator Transient Analysis
- MOV Impact
- Conclusions NEXTera'"
ENERGY ~
3
Overview
- Calculations have been performed using conservative assumptions and methods of analysis
- Testing verifies the EDG calculation reflects actual plant response
- MOV periodic verification testing and design control programs ensure that MOVs meet EDG transient analysis inputs
NEXTera'u ENERGY ~
POINT 4
BEACH
Agenda
- Introductio
- Overview c=>. Emergency Diesel Generator Transient Analysis
- MOV Impact Assessment
- Conclusions NEXTera'"
ENERG-Y ~
POINT 5
BEACH
- Analysis demonstrates that EDGs and Safety Related (SR) equipment are capable of supporting design bases functions
- EDGs and Safety Related Equipment are conservatively modeled
- EDG response has been validated against testing
- MOV evaluation methodology is conservatively inputted into the model
- EDG transient analysis shows an overall improvement of the EDG response by the AFW upgrade design NEXTera'"
ENERGX ~
POINT 6
BEACH
EDG Transient Calculation Model
- Model inputs
- Equipment models
- MOVs are conservatively modeled at locked rotor for the entire event
- EDG modeling inputs Governor Excitation Steady state parameters
- Plant configurations Design bases versus normal lineup Cold loading New AFW timing Random loads 7
EDG Configuration One Line G01 -A Train G02 -A Train G04 - B Train G03 - B Train Unit 1 MDAFW Unit2 MDAFW Pump Pump
~
I3 L
480 VLC 480 VLC NEXTera ru ENERGY ~
8
.!mPact of AST, AFW, and EPU Modifications
- The AST Modifications Removing approximately 50 HP of non-essential load from automatically loading on the EDG Control Room Emergency Filtration automatically load onto the EDG
- AFW Modifications Replaced 480 volt 250 HP motor with a 4160 volt 350 HP motor Changed DBA load sequence from 10.5 seconds to 32.5 seconds nominal to no longer start with the CS pump Loss of Voltage (LOV) relays EPU Modifications have no significant impact 9
NEXTera w
ENERGY ~
POINT BEACH
futstem Voltage Response during a LBLOCA 2A-05 LBLOCA Response
- > 135 o
CD
-H
~
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I
~
115
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?fl.
95
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~ J \\ J ~ I I \\7 IU+:l-L---U ca o
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55 I'
o 20 40 60 2A-05 Normal 2A-05 Design 10
§ystem Voltage Response during Non LBLOCA 2A-05 CSP and AFW Start at 32.5 Seconds o
20 40 60 2A-05 Normal 2A-05 Design 75 -H 11f-115 135 --1 f!-\\
- > 155 o
CD "f"'"
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(1) 95 C)
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NEXTera'"
ENERGY a POINT 11 BEACH
~ment Evaluations
- 4160 Volt and 480 volt Switchgear loads All loads start and run properly LOV setpoints are acceptable No protective device trips
- MOe loads Protective devices do not trip Loads start and run to meet DBA
- MOV loads MOV and delays are conservatively modeled MOV program requirements are met Containment Spray random load is considered Protective Devices 12
Conclusions of Transient Analysis
- Voltage response during a LBLOCA supports design requirements
- Equipment evaluations have been based on the predicted EDG dynamic response and load sequence
- The EDG transient analysis shows an overall improvement of the EDGs by the AFW upgrade design and AST modifications NEXTera'u ENERGY POINT 13 BEACH
Agenda
- Introduction
- Overview
- Emergency Diesel Generator Transient Analysis c==:>. MOV Impact
- Conclusions NEXTera'v ENERGY ~
POINT 14 BEACH
MOV Evaluation
- Stroke time evaluation
- Periodic verification
- MOV Margins NEXTera'*
ENERGY POINT 15 BEACH
Stroke Time Margins
- Minimum voltage used has margin prior to valve stall point
- Stroke time calculation uses pullout torque.
- Assumed stem friction higher than actual tested stem friction
- Assumed valve seat friction higher than tested friction during MOV DP testing
- For lowest margin valve required Cv is achieved prior to full stroke of valve NEXTera'"
ENERG', _,.
~
POI NT 16 BEACH
Periodic Verification
- Valve seat friction is controlled by the GL 96-05 Periodic Verification program
- The packing friction is tested and procedurally controlled
- The stem to stem nut friction is tested
- PM for valve stem lubrication 17
Example MOV Margins
- Electrical margin Voltage 30.7%
- Mechanical margins Stem Friction 13%
Stem Load Profile 36.3°~
Operator Efficiency 200/0
- Hydraulic margins Valve Position Margin A Header volume 30%
20%
18
Agenda
- Introductio
- Overview
- Emergency Diesel Generator Transient Analysis
- MOV Impact c=:). Conclusions NEXTera'"
ENERG' I - 1f....
19
Conclusions
- Point Beach EDGs meet design bases requirements
- Calculations have been performed using conservative assumptions and methods of analysis
- 3 The licensee agreed to supplement its application with two additional license conditions to support proposed modifications, as described below:
(1) Modifications will be implemented by the end of the spring 2011 Unit 2 refueling outage to ensure the motor-driven auxiliary feedwater and the turbine-driven auxiliary feedwater pump systems on each unit are powered from independent direct current power sources.
(2) Modifications will be implemented by the end of the spring 2011 Unit 2 refueling outage to reduce EDG loading such that the maximum loading will not exceed the 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of the EDGs.
There were no members of the public in attendance. Public Meeting Feedback forms were not received.
Please direct any inquiries to me at 301-415-3049, or Terry.Beltz@nrc.gov.
IRAJ Terry A. Beltz, Senior Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-266 and 50-301
Enclosures:
- 1. List of Attendees
- 2. Slide Presentation Handout Provided by the Licensee cc w/encls: Distribution via Listserv DISTRIBUTION:
PUBLIC RidsRgn3MailCenter Resource LPL3-1 R/F RidsOgcRp Resource RidsAcrsAcnw_MailCTR Resource SGardocki, NRR RidsNrrDorlLpl3-1 Resource RMathew, NRR RidsNrrPMPointBeach Resource TScarbrough, NRO RidsNrrLABTully Resource GMatharu, NRR DMerzke, EDO R-1I1 JJanovich, R-1I1 CSteger, NRR BWolfgang, NRR MFranan, NRR ADAMS Accession Number: ML103330446 OFFICE DORLlLPL3-1/PM DORLlLPL3-1/LA DORL/LPL3-1/BC DORLlLPL3-1/PM NAME TBeitz BTuily RPascarel1i TBeitz DATE 12/06/10 12/06/10 12/14/10 12/14/10 OFFICIAL RECORD COpy