ML051960331

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Presentation Slides from Public Meeting with FPL
ML051960331
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 07/13/2005
From:
Florida Power & Light Co
To:
Office of Nuclear Reactor Regulation
Moroney B, NRR/DLPM, 415-3974
References
Download: ML051960331 (26)
v • d • e


Text

S- '-4'- -

0 FPL tS eli ,.I FPLIW/NRC Interface Technical Meeting Proposed Increase in St. Lucie Unit 2 Steam Generator Tube Plugging Limit July 13, 2005 Agenda

  • Purpose of meeting
  • Recap of upcoming submittal

- Approach to analyses

- Proposed Tech Spec/COLR changes

  • System parameters (as requested by NRC at last meeting)

- Current cycle predictions and actual values

- Projections for 42% tube plugging

  • Analyses update

- Applicability of methods and correlations

> ~Status of event analysis 2

APL

I Is Agenda (cont.)

  • Feedback from NRC on issues to address in submittal if different from current design bases
  • Discussion on partial submittals
  • Feedback and comments RPL Purpose of Meeting
  • To brief the NRC on upcoming plant license amendment for 42% tube plugging to facilitate NRC review
  • To address issues/requests from the last meeting of May 2005
  • To provide an update on ongoing analyses
  • To discuss and obtain NRC feedback on potential partial submittal iteti 4

a FAL

I Approach to Analyses

  • Submittal will use the same methods already approved by the NRC in Amendment 138
  • Submittal will use the same analysis assumptions as recently approved by the NRC for 30% SGTP, except for

- Inputs and operating parameters changed to be consistent with plant configuration for Increased SGTP, reduced flow and reduced power, and

- As required to achieve acceptable margins (reduced COLR limits, etc.)

5 Approach to Analyses (Contd.)

  • Submittal will include re-analysis of all limiting non-LOCA events
  • Submittal will include re-analysis of LOCA events
  • Since a single operating point is identified for Cycle 16, a range of temperatures will not be addressed as done for 30% SGTP

- Confirmation of continued applicability of the temperature range (535°F to 549°F TCold) for DNB will be provided for the DNB Tech Spec (TS 3.2-5 and TSICOLR Table 3.2-2) _

)

6 FPL

i Proposed Tech Spec/COLR Changes

  • TS LCO 3.2.5, DNB Parameters: Include additional footnote in Tech Spec Table 3.2-2 for 335,000 gpm RCS flow rate:

'if the Reactor Coolant System Flow Rate Is less than 335,000 gpm but greater than or equal to 300.000 gpm, then the maximum reactor THERMAL POWER shall not exceed 89% of RATED THERMAL POWER of 2700 MWth.

  • TS SR 4.2.5.2: Modify footnote on Tech Spec page 3/4 2-14 to replace "2 90%" with "2 80%"
  • Definition of RATED THERMAL POWER unchanged
  • COLR changes as required to achieve R aLplableargins-LeA rmLL System Parameters for 30% Tube Plugging Parameter Analysis Actual Proiection for 18.9%

Tube Plugging 30% 18.9% 18.9 %

RCS Flow 335,000 -a76,000 -872.000 (gpm)

SG Pressure 790 837 836 (psia)

Cold Leg Temp 549 -548.5 (F)

PL8

NRC Requested System Parameter Projections for 42% Tube Plugging THERMALVESIGNPARAMETERS CCt CeW2 NSSSPtner % t9 n9 MVvt 2424 2424 Rr.octr P.ser, MWI 24OJ 2404 TkterDc1 Flo. Lt*D tlpt MIS.&W^ ISD0llm R.mor tn-Ih/ir 11344 113S Rract-r C..a.t Pnrt.. p.1. 2250 2250 Coreh~tt  % 3.7 3.7 Rrxtor CtWl..tl Trmpenlre. IF' COMOwlet 6024 t 603.9 V=od O.1ct WAi 0019 CoreAwn S7 5755 S7t Vrmd Ament* J S6A 757.

VerYCere lpkt SJ6t. S47.1 see.. Grtntor"O.flt 54S5S S46, StromSretow St".TjmVm.vF 506.9 510.0 9ir.m.Pr,or pD<o 724 732 Srom FlnwwII IbWr# l IOJA2 It.2 FeedTmpmrImmorF 420tlS 42tJ0 Mnt., %-mC0.25 0.251 DhsirpF'F.hr. sq.ft.-FTU 0445017 SD1117 TuhrPt.bIn.f.% 42.0 42.0 Zrr. lod Tpemrrwtre-F 5 I SJ.2I .,"Im3

L Applicability of methods and correlations

- Each analysis will include a determination of the applicability of methods and correlations as applied to 42% SGTP and 89% power to ensure validity of the results.

- The results of the applicability determination will be summarized in the submittal.

- No method or correlation has been identified to be outside the bounds of applicability for the revised operating conditions.

L10

Applicability of Methods - DNB Correlations

- Pressure (psia) 1750 to 2415

- Local Mass Velocity (Mlbm/hr-ft 2 ) 0.8 to 3.16

- Local Quality (Fraction) -0.14 to 0.22

  • DNB codes identify when above parameters are outside of the above ranges of the DNB correlation.

11 MPL,,e Applicability of Methods - DNB Correlations

- Pressure (psia) 1750 to 2415 The Thermal Margin I Low Pressure reactor trip and High Pressurizer Pressure Reactor trips ensure that the RCS pressure remains in the range of pressures associated with the DNB correlation. For events analyzed beyond the time of reactor trip resulting in a large RCS pressure drop, such as post-trip steamline break, other approved DNB correlations are used (W-3 correlation).

(TMILP floor pressure > 1800 I3sla) 12 FFL

Applicability of Methods - DNB Correlations

- Local Mass Velocity (Mlbm/hr-ft2 ) 0.8 to 3.16 The Low RCS Flow reactor trip ensures that the mass velocity conditions remain in the range associated with the DNB correlation. For events analyzed beyond the time of reactor trip, other approved DNB correlations are applied (W-3 correlation).

(Expected mass velocities in the range of at leastg1;0)pi_-T, 13 Applicability of Methods - DNB Correlations

- Local Quality (Fraction) -0.14 to 0.22 The Thermal Margin / Low Pressure reactor trip and High Pressurizer Pressure Reactor trips ensure that the local quality remains in the range of pressures associated with the DNB correlation. For events analyzed beyond the time of reactor trip resulting In a large RCS pressure drop, such as post-trip steamline break, other approved DNB correlations are applied (W-3 correlation).

FFOL, 14

Applicability of Methods - DNB Correlations

  • W-3 Correlation Ranges

- Pressure (psia) 1000* to 2400

- Local Mass Velocity (Mlbmlhr-ft 2 ) 1.0to 5.0

- Local Quality (Fraction) -0.15 to 0.15

  • A lower limit of 500 psia has been approved based on a DNBR limit of 1A5 Instead of 1.30
  • DNB codes identify when above parameters are outside of the above ranges of the DNB correlation.

F PL Applicability of Methods - SG Models

  • SG Models benchmarked against plant data (SG Pressures)
  • Adjustments made to fouling factor to match plant data
  • Used to define global boundary conditions for the safety analysis models

- Steam generator pressures

- Circulation ratios 16

Applicability of Methods - SG Models

  • SG Models use standard heat transfer correlations

- Dittus - Boelter for tube side

- Jens & Lottes for shell side (benchmarked against plant data)

- SG plugging levels have been successfully analyzed and licensed for Westinghouse-designed plants with conditions similar to St. Lucie Unit 2 42% SGTP.

- Conditions associated with 42% SGTP are within the ranges of SG model correlations.

17 R:L

Applicability of Methods - SG Models

Conclusions:

- SG Model results compare very favorably to actual plant data for high plugging levels

- 42% SG Tube Plugging conditions are within the ranges of the SG model heat transfer correlations.

S 19 Applicability of Methods - RETRAN Model RETRAN SG Model

- Currently used for conditions that bound the expected conditions associated with the 42% SGTP program

  • Low RCS flow conditions analyzed for Loss of Flow events, Loss of Offsite Power event, Feedline Break without offsite power event, etc.

- Although total RCS flow tends to drop with increased plugging levels, mass velocity on tube'side tends to increase

  • Low secondary side flow conditions analyzed for part-power CEA withdrawal event, zero-power events, etc.

.tes< ;20 FPL ,e

Applicability of Methods - RETRAN Model RETRAN SG Model

- Uses standard well behaved and well known heat transfer correlations

- SG Model successfully used to model SG plugging levels for Westinghouse-designed PWR plants

- CE RETRAN SG Model essentially the same as the SG model used for numerous Westinghouse plant designs which cover a wide range of operating and accident conditions.

- RETRAN SG model is the same model as used in the X 30% SGTP safety analyses.

21 R:PL

Applicability of Methods - Licensed SG Plugging Levels Examples of Ucensed Westinghouse SG Designs Parameters Westinghouse St. Lucie 2 Tube OD (inches) 0.688 to 0.875 0.75 Number of Tubes 5,626 to 10,025 8,411 per SG Heat Transfer Area 55,000 to 123,538 90,232 ICS Flow/SG 93.600 to 157,500 150,000- 42%

(gpm)1500 42 Power Level/SG 894 to 1707 1360-100%

(MWt)04o10 1212-89%

Plugging Levels (%) 0 to 30 42 i 23 R:PL Analysis Update

  • Fuel Performance:

- Analyses are on-going

- Preliminary indications:

  • Most of the fuel performance results are expected to be bounded by the 30% case due to power reduction
  • Corrosion characteristics for fuel are also expected to be better at lower power level
  • Fuel Mechanical Design:

- Reduced flow impacts are being analyzed

- Analyses are on-going

  • No issues are expected in meeting applicable acceptance criteria. ._

24 R:PL

Analysis Update

  • Fuels Thermal and Hydraulic Design

- Currently licensed VIPER-W model is being used to generate departure from nuclear boiling analyses to support the 42% SGTP

- Analyses are on-going

- Analysis of SGTR is on-going

- Results of SGTR analysis will be used In the radiological dose calculations using AST methodology

- Same method as used in the 30% SGTP analysis.

25 Analysis Update

- Analyses are on going

- Employing the same methods as used for 30% tube plugging

  • Post LOCA long term cooling - CENPD-254-P-A

- Full reanalysis is being performed

  • Full spectrum of cases are being analyzed

- All fuel types for Cycle 16 are being analyzed

- Preliminary Results indicate need for changing some COLR parameter limits (PLHGR decrease from 12.5 to 12 kwlft)

FRL

Analysis Update

  • Post LOCA LTC-Boron Precipitation: An issue was raised by the NRC during the Waterford EPU review

- Issue relates to impact of voids in core on post-LOCA boron precipitation

- Additional analyses were performed to show conservatism of the model.

- The issue was resolved for Waterford

- Similar additional analysis will be performed for the 42% tube plugging.

27 rFL Analysis Update

  • Containment Peak Pressure Analysis

- Evaluation against the current analysis of record based on no increase in core AT is ongoing

  • Primary Line Break Outside Containment

- No explicit analysis

- Event is insensitive to RCS vessel flow rate and tube plugging

- Evaluation based on existing analysis  !

ongoing 28 FAL

Analysis Update: Non-LOCA Impacts

  • Reduced RCS flow

-DNB

-Peak pressure

  • Reduced heat transfer area

- Heatup events

  • Reduced RCS Volume

- Boron Dilution/Heatup and Cooldown events 29 R=L Analysis Update: Assumptions Current To be Analysis Addressed SGTP 30% 42%

TDF 335,000 gpm 300,000 gpm MMF 341,400 gpm 314,000 gpm Target 100% 89%

Maximum Power Target Tavg 576.5 545XyiT FPL

Analysis Update: Non-LOCA Scope

  • Setpoints Confirmation
  • Increase in heat removal events
  • Decrease in heat removal events
  • Reactivity and power distribution anomalies
  • Decrease in reactor coolant inventory 31 RPL Analysis Update: Tools (Non-LOCA)
  • No new analysis tools
  • NRC approved codes

- Same computer code suite as 30%

SGTP program

  • RETRAN
  • FACTRAN
  • TWINKLE

Submittal - Safety Analyses (1)

Event UmniingCase(s) Notes Feedwater Malfunction, HFP Increased Flow case Non-limitng DNB event Reduced power would yield less limiting results Post-Trip Stearnline Break Post-Trip with offsite Power Analyzed for reduced RCS flow.

case Pre-TripSLB Breaks forlimiting MDC A LImitIng DNB event. Failure ofthe Fast case BusTransfer mad Loss of Offsite Power wll be addressed.

Loss of Condenser Vacuum Primary side pressure case A Umiting RCS pressure case Asymmetric Steam Generator DNBR case Non-limiting DNB event. Reduced power Transient would yield less limiting results. RCS pressure cases also non-limiting.

CVCS Malfunction Pressurizer Filling case Non-limiting event and reduced power should provide additional margin RCS Depressurization DNBR case Non-limiting DNB event Reduced power would yield lesslimiting results.

-e,-"

33 I

Submittal - Safety Analyses (2)

Event Ulmiting Case(s) Notes Feedline Break Peak RCS Pressure for A Umiting RCS pressure event. Failure of breaks < and > 0.20 Ft' the FBT will be addressed.

Loss of Flow Complete Loss of Flow- A UmLiting DNBR event DNB case Locked Rotor DNBR and peak pressure A Limiting DNBIRCS pressure event.

case Failure of FBT & LOOP will be addressed Rod Withdrawal from DNBR Limiting statepoints will be analyzed with Subcritical lower RCS flow Rod Ejection HFP cases Lower power is non-limiting. Analyzed for confirmation with respect to current licensing basis.

Rod Withdrawal at Power All DNB cases examined Umiting evett. Dynamics of trip functions at the lower RCS flow must be examined.

Dropped Rod Depends on Core Design Limiting DNB eventLTransient StatepoinIs should remain essentially unchanged 34 R~L

i Submittal - Safety Analyses (3)

Event Limiting Case(s) Notes Boron Dilution Minimum Operator Action Analyzed for reduced RCS volume which Time for All Cases minimizes operator action time Stearn Generaor Tube LOOP Amalyzed with support from FPL or dose Rupture considerations Large Break LOCA All cases Small Break LOCA All cases __

Post-LOCA All cases Nuclear Design Only asrequired to address Cycle-specific reload calculations Chapter 15analyses Thenmal-Hydraulic Analyses LimitingTransients To suplement cycle-specific reload calculations Fuel Performance Analysis Evaluation To supplement cycle-specific reload calculations FPL Decrease in Feedwater Temperature Acceptance Criteria

-DNBR Case(s) for Reanalysis

-HFP (bounds HZP)

Potential Limiting Modeling Conditions

- None 0FFPL s36

Increase in Feedwater Flow Acceptance Criteria

- DNBR Case(s) for Reanalysis

- HFP

- HZP Potential Limiting Modeling Conditions

- None

.I-,

Pre-Trip Steam System Piping Failure Acceptance Criteria

- DNBR

- Peak linear heat rate Case(s) for Reanalysis

- Limiting MDC cases

  • Failure of fast bus transfer by overlaying flow coastdown onto the with-flow case
  • Break coincident with LOOP at time zero Potential Limiting Modeling Conditions

,qv0_11M

- None V,- . u.;. .-.

38 0

Post-Trip Steam System Piping Failure Acceptance Criteria

- DNBR Case(s)

-With offsite power available Potential Limiting Modeling Conditions

- None ng 0 39 Loss of Condenser Vacuum Acceptance Criteria

- DNBR

- Primary and Secondary overpressure Case(s) for Reanalysis

- DNB

- Primary overpressure

- Secondary overpressure

- Inoperable MSSVs Potential Limiting Modeling Conditions

- None rm40

Feedwater System Pipe break Acceptance Criteria

- Secondary Overpressure

- Primary Overpressure Case(s) for Reanalysis

- Primary peak pressure < 110% of design pressure

  • Small break with failure of fast bus transfer (FFBT)
  • Large break without FFBT

- Primary peak pressure < 120% of design

  • Large break with FFBT

- Secondary peak pressure

  • Limiting break size (without FFBT)

Potential Limiting Modeling Conditions

- None 41 R:PL Asymmetric Steam Generator Transients Acceptance Criteria

- DNBR

- Peak linear heat rate Case(s)

- Maximum SGTP (42%)

Potential Limiting Modeling Conditions

- None 42 RFL.

i .

Complete Loss of Flow Acceptance Criteria

- DNBR Case(s)

- Maximum SGTP Potential Limiting Modeling Conditions

- Mass flux range associated with the CHF correlation 43 RPL Locked Rotor Acceptance Criteria

- DNBR

- Primary overpressure

- Cladding average temperature Case(s)

- Rods-ln-DNB with failure of fast bus transfer (FFBT) and subsequent Loss of Offsite Power (LOOP)

- Peak pressure / maximum clad average temperature with FFBT and subsequent LOOP Potential Limiting Modeling Conditions

-Mass flux range associated with the CHF correlatio6i S5T 0=P 44

Rod Withdrawal from a Subcritical or low Power Condition Acceptance Criteria

- DNBR and Fuel centerline temperature Case(s)

- DNBR

- Peak fuel centerline temperature Potential Limiting Modeling Conditions

- Mass flux range associated with the CHF correlation

- Addressed with the use of other approved CHF correlations (W-3) if necessary.

45 FRPL Rod Withdrawal at Power Acceptance Criteria

- DNBR

- Fuel centerline melt

- Primary and secondary overpressure Case(s)

- DNBR - 89%, 65%, 50% and 20% power at both maximum and minimum feedback

- Overpressure - 100%, minimum feedback Potential Limiting Modeling Conditions

- None 0 .PL~

46

Feedback from NRC on New Issues to be Addressed in the Submittal

  • Comments on

- Analysis Approach

- Proposed Technical Specification changes

  • Other issues?

47 FPL Discussion on Partial Submittals

  • Two Submittal Options were suggested at the previous meeting:

- Complete Submittal

  • Submittal on November 1, 2005 (similar to 30%

SGTP submittal, and subsequent RAls)

Phase Submittal

  • 1 "t Phase submittal about a month in advance
  • Final submittal on November 1, 2005
  • NRC approval needed prior to the start of Cycle 16 outage, currently scheduled for 4/26106 0P 48

Discussion on Partial Submittals (Contd.)

  • 1St Phase submittal

- Approximately 6 to 7 of the Non-LOCA analyses:

  • RCS Depressurization
  • Loss of Flow
  • Locked Rotor
  • Rod Withdrawal from Subcritical 49 Discussion of Submittal Content
  • Same format as 30% SGTP Submittal to facilitate NRC review.
  • Summary of changes to the 30%

Submittal.

  • Comparison of Analysis Results to 30%

SGTP submittal results and to the regulatory limits.

0FAL 50

Feedback and Comments

  • Open Discussion
  • Proposed next meeting a,- Deio51 F
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