ML021500303
| ML021500303 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 05/02/2002 |
| From: | Florida Power & Light Co |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| Download: ML021500303 (19) | |
Text
FPL Florida Power & Light Company St. Lucie Nuclear Plant UNIT 2 STEAM GENERATOR OPERATIONAL ASSESSMENT FOR CYCLE 13 PRESENTED TO NRR MAY 2, 2002 ENCLO52$UZc '?
- SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT AGENDA Opening Remarks Raj Kundalkar, VP Engineering S/G Information Gary Boyers, S/G Specialist Inspection Preparations Inspection Evolution Operational Assessment Brian Woodman, APTECH Eng.
Closing Remarks Raj Kundalkar, VP Engineering 1
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT OPENING REMARKS - Raj Kundalkar, VP Engineering Meeting Objective
"*Review S/G Operational Assessment for Cycle 13
"*Demonstrate Inspection Results Support Full Cycle Operation FPL Philosophy
"*Committed to Safe Operation
"*Implementation of NEI 97-06, S/G Program Guidelines
"*Incorporate Industry Experience
"*Conservative &Proactive Approach to S/G Management 2
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT EOC 12 S/G Examinations
- 100% Bobbin Inspection Augmented by Extensive Plus Point Probe Inspections
- Preventatively Plugged the Most Susceptible Tubes with Dings Post-Outage Work and Operational Assessment
"*Historical Data Review Shows No Step Change in Degradation
"*Multi-Cycle Model Successfully Benchmarks PSL-2 Experience
"*Model Results Support Full Cycle Operation 3
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT S/G Design CE Model 3410 8411 Tubes/ SG j~.F~.
OEtT 4
.i - u Or* .
- A-600 HTMA Tubing
- CS Lattice Support System
- Explosive Expansion rWo "
Tubesheet Joint
- Tubes Plugged SG A - 474 (5.6%)
SG B - 539 (6.4%)
- T-Hot -600OF .u*.,.r."x 4
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Inspection Plan for EOC 12 Inspection Plan
- Bobbin Probe: 100% Bobbin Probe Full Length
- Plus Point Probe: 100% of Hot Leg Top of Tubesheet 30% of Row I & 2 U-bends 30% of Hot Leg Dings > 5 Volts Free Span Indications (New or Show Change)
- Plus Point Profile of All Potential Corrosion Indications
"*Contingency Plan for Free Span Cracking
" In Situ Pressure Test as Required 6
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Inspection Preparations for EOC 12 Small Amplitude Axial Indications First Reported at Eggcrate Supports at EOC 11 were Incorporated into EOC 12 Inspection 0 Updated Data Analyst Training & Performance Demonstration 0 Refined Computer Data Screening (Secondary Analysis)
- 1 of 15 Indications Did Not Confirm on Alternate Bobbin Channel 0 Confirmation on Alternate Bobbin Channels Eliminated for EOC 12 SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Inspection Evolution for EOC 12 Number of Eggcrate Bobbin Indications Greater than Expected
"*Over 900 Plus Point Diagnostic Examinations
- Direct result from the guidelines change.
"*Primarily at Lower Three Hot Leg Supports Detection of Axial ODSCC at Dings 0 Prompted Supplemental Training &Inspection Expansion
- 3 Periphery Tubes -1" Above Hot Leg Tubesheet 0 3 Additional Tubes at Other Locations on Hot Leg 8
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Inspection Evolution for EOC 12 Plus Point Examinations at Dings
"*All Dings Hot Leg Tubesheet to 1 st Support
"*All Dings in U-Bends and 90° Bends
"*All Dings > 5 Volts 1st Hot Leg Support to the Diagonal Cold Leg Support
"*All Dings >10 Volts in Cold Leg Straight Region Bobbin Probe Qualified for Dings < 5 Volts SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT In Situ Pressure Testing for EOC 12 27 Indications Tested With No Burst or Leakage Mechanism Tested Pressure Axial ODSCC at Eggcrates 9 4950 -5000 psi Axial ODSCC at Dents 5 4950 -5000 psi Axial ODSCC at TTS 6 4950 -5000 psi Axial IDSCC below TTS 2 4950 -5000 psi Circ ODSCC at TTS 4 5550 -5600 psi OD Volumetric TTS 1 4950 -5000 psi Selection Criteria Exceeded EPRI Minimum Guidance
- Mechanism & Location
- Calculated Burst Pressure & Leakage
- Maximum Voltage, Depth, Length & Percent Degraded Area 10
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Extensive Historical Reviews Show Flaws at Eggcrates Were Present in Prior Inspections
..... ....................... *B
- 1997
.......... *....... ýiiv 1998
............ "*'"ff *60i~ i~i'2000 "E2001......................
i"~'."i""'"................... * .... ";.... ...... ' i......
... .. ... .. .. .... .......EOC .... 9..............EOC ........ ...........
10.EOCI11.EOC
.......... ........... ........... 12
........... .... ......o....
Total
......... ' "B.....................
...... .............. i..............
.... ...... ........................... .............. i..............
SIG A 6 36 41 19 102 SIG B 35 6869 39 211 S..............................* .................................. i.................................. <...................................< ................................... ..................................
Total 41 104 110 58 313*
- S ...i-.-r.i ii - .- -. ..........
-i i i ........... . ......
- -i ..- ..................... .................................
i.................
ote: 1 n~dic~ati~ons. waern !in.i~týt~y~ rteoadat EG.11
.... ... ... .... 298 additional indications reported at EGG 12 11 11 SL 2 EOC 12(11/01) STEAM GENERATOR b*
" "* SL 2 EOC 12 (11101) STEAM GENERATOR OPERATIONAL ASSESSMENT Conclusions from EOC 12 Historical Review Work
- Degradation Trend is Typical for Unit with A-600 MA Tubing
- Large Apparent Increase in ODSCC at Eggcrates is Due to Change in Data Analysis Reporting Criteria
- Growth of Axial Indications at Dings Occurred Over 2 or More Cycles
- Preventatively Plugged the Most Susceptible Population of Dings
- Confirmation on Alternate Bobbin Data Channel is Inconsistent When Indication is at Edge of Eggcrate 12
- SL 2 EOC 12(11101) STEAM GENERATOR 2 EOC S~SL 12 (11/01)
OPERATIONAL ASSESSMENT STEAM GENERATOR Outline of Operational Assessment Discussion
- General Description of Operational Assessment Model
- Application to ODSCC at Eggcrates
- Application to ODSCC at Dings
- Probability of Detection for ODSCC at Dings 13 SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Operational Assessment
"* Assessment Of Structural/Leakage Integrity Relative To NEI 97-06 At EOC 13
"* Monte Carlo Simulation Of Steam Generator Degradation
- Tracks Initiation, Evolution And Detection Of Simulated Flaw Population Over Several Cycles/Multiple Inspections
- Structural And Leakage Integrity Evaluated For Each Simulated Flaw Throughout Period Of Analysis
- Output Includes:
- Risk Of Tube Burst
- Risk/Statistics Of Leakage Under Accident Conditions 14
h§ SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Basic Processes
"*Initiation
- Weibull Model
"*Flaw Growth
- Lognormal Model
"*Detection
- Logistic Model
- Repair on Detection
- Burst/Ligament Tearing
- Framatome Model
- Leakage PICEP Model with Fracture Mechanics Crack Opening Area 15 SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Overview Axial ODSCC At Eggcrates
"* Largest Number of Corrosion Indications in 2001
"*Apparent Large Increase in Number of Indications
"* Moderate Flaw Depth Distribution
"* Extensive Profile Analysis Performed
"* No In Situ Burst or Leakage Occurrences 16
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT PSL2 Results of Historical Review ODSCC at Eggcrates S1997 i 1998 2000 2001 EOC 9 EOCI10 EOCC11 EOC 12 Total
. . . . . . . . .41. . . . . . . ...........
S...........................
Total 104 ..........
110 ......... .... . . . ........
. . . . . . . .58. . . . . . . . . . . . . . . . . .313"
- ,Note: 15 indications výere intillreore eC1ia 298addtioal d....
..i .............. ....... ............ ndiatinsreported
....... at EOC 12 .. ........ ... ...... .................
THE RATE OF INCREASE IN INDICATIONS IS CONSISTENT WITH INDUSTRY EXPERIENCE 17 SL 2 EOC 12 (11/01) STEAM GENERATOR
, OPERATIONAL ASSESSMENT Axial ODSCC at Eggcrates - Bobbin Probe POD Model
- Basis for model
" Multiple analyst site-specific performance demonstration using pulled tube data base
"*NRC ANL round o robin results based on multiple analyst participation ° 1
"*Supported by PSL 1 pulled tubes
SL 2 EOC 12 (11101) STEAM GENERATOR OPERATIONAL ASSESSMENT PSL2 SG B Benchmark CUMUATIV POCTE 00C F.AW5 0;5L-2 SO-B
.ISTORCALDA.A...........
- =:. .... ..................
0b iii~ ~i~~i!... ............ i ;* * ; ;
.5 6
.0. ... ....
0O OBSERVED 0..
EFF .... 2.. OS Ef F.1Y 19
S~ SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT I Results Of Eggcrate Evaluation ADDITIONAL NUMBER OF PROBABILITYOF BURST AT INDICATIONS PREDICTED 3xNODP
. ............................................................ .. ... 3.............................
........................ .......... 60 0.010 S............................
SIG A ......................................... ........................................................................ ..
S............................
SIG B .....................................................................................................
100 ....................................................
0.036 Steam Generators Projected to Meet NEI 97-06 Requirements at EOC 13 21 SL 2 EOC 12 (11101) STEAM GENERATOR OPERATIONAL ASSESSMENT Overview - ODSCC At Dings
"*First Reported in 2001
"*Small Number of Flaws [61
- Non-random Distribution of Dings Near Tubesheet
- Most High Amplitude Dings at Peripheral Locations Based on Bobbin Probe
- Largest Flaws in Dings Near Tubesheet
- Thorough Look Back Evaluation
- No In Situ Burst or Leakage Occurrences
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Critical Model Elements
"* Probability of Detection Model
"*Plus Point
"*Bobbin
"*Simulation Process
"* Initiation of ODSCC In Dings
"* ODSCC Flaw Growth Rate
"* Flaw Length 23 SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT
+Pt POD Model Development for Axial ODSCC in Tube Dings
- Starting Point
- Free-span +Pt Detecton Performance for in-_ ___
Free-span Cracking :.
- This Performance Is i 17 the Limiting Upper i K___
Bound inthe *.
Absence of Tube i Indentations
- Free-span Performance Is Then Degraded Based on the Estimated Impact of Tube Dings on;+ .........
Detection 24
- SL 2 EOC 12 (11101) STEAM GENERATOR OPERATIONAL ASSESSMENT
+Pt POD Model Development for Axial ODSCC in Tube Dings
"* Free-span "Misses" are Retained iiiiiiii6 .. *-2661xl)y(1+,e)(-2.77n +(.1 6)-))
2EEE:3iE*:::::~iEEEiE3[+ P Pt Free- ispaniii~ii~i Missed in the Absence of Tube Indentations -----------
"* Free-span Hits are I Excluded O.. -1 -
- Detected in the /
Absence of Tube o . --
Indentations
" Hit/miss Data from /
Signal Superposition :::a 2-. -_,_----
Study Added
- Upper Extremes of ai* =-*--- r -
the Explanatory 7.1. /
Variable 2 .....
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Westinghouse Ding/Defect Superposition Study
"* InSitu pressure tested indications with a range in depths were superimposed on Unit 2 ding signals using eddy current analysis software
"* Overall detection performance for the various test conditions is summarized below in a Hit I Miss table Estimated Met R89L57 R12L28 R126L48 R88L148 Depth, %TWN Largest Vvm Largest Vpp Median Mean R8L144 - 33% Miss Hit Hit Hit R47L51 - 42% Miss Hit Hit Hit R133L91 - 42% Hit Hit Hit Hit R53L137 - 47% Hit Hit Hit Hit R109L65-54% Hit Hit Hit Hit R118L564-73% Hit Hit Hit Hit R117L61-82% Hit Hit Hit Hit 26
SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT
+Pt POD Model for Axial ODSCC in Tube Dings Worst Case Hit/Miss ......
M 4i ik ...........
Data Used Added to Free-span Miss Data as Input ... .--..--Iii -- Ii..
for Tube Ding POD Bootstrap Estimates to Study Sensitivity of Uncertainties in POD Best Estimate POD Justified for Input to the Operational Assessment ......
I. 2..........
.... ... aI.. -ý f............
.a. .U 27 27
SL2EOCI2(11/0l)STEAM GENERATOR S~SL 2 EOC 12 (11/01) STEAM OPERATIONAL ASSESSMENT GENERATOR Initiation of ODSCC in Dings Weibull Model Used for Initiation Process in Ding Population
"*Limiting Slope Parameter of 4 Assigned
- Exceeds EPRI Comprehensive Report of Observations of Field Data
"*Scale Parameter Estimated Using OA Model
- Scale Parameter Adjusted to Agree with EOC 12 Results 31 SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT Growth Rates RANGE OF ODSCC GROWTH RATE DISTRIBUTIONS
"* Growth Rate Based On Extensive Field 0.7 Observations S 06I
"* Range Of Growth 0.3 Rate Distributions 0.
Illustrated
"* High Growth Rate Curve Used In 0.2 . . --- -
--_I - .. ... . ..
ODSCC At Dings 32IG Evaluation 0.C l i .. i.... ! i .i... . L WE NLOWES 0 5 10 15 20 25 30 35 40 'TYPICA STRUCTURAL DERTH GROWTH RATE - %THROUGHWALLIEFPY 32
2 EOC 12 (11/01)STEAM GENERATOR OPERATIONAL ASSESSMENT Potential Flaw Length Distribution 0 Ln-,
tn tar TY vlm .
P0I I40 I 0
"* Flaw Length Distribution Determines Fract:ion Of Deep Flaws That rst 0.7t Are Potential Bur Candidates
"* Developed From 0.0.
PSL-2 2001 Ding M0.4 Length Measurements 0.4 0.0 0.0 7.0 1.2 0.4 0.0 0.0 0.0 0.0 . 0 A4 1 -II .L0.nL,. (Inch-10 33 SL 2 EOC 12 (11101) STEAM GENERATOR OPERATIONAL ASSESSMENT Results of ODSCC at Dings Evaluation ADDITIONAL NUMBER OF PROBABILITY OF BURST AT INDICATIONS PREDICTED 3xNODP EOC3 EOC3 SIG A 4 0.033 S/G B 10.007
" Conservative Model Elements
- Growth
- Burst Model
- Flaw Length
- No Credit Taken for Ligaments
- Initiation
"* Accommodates Risk Associated With New Mechanism
SL 2 EOC 12(11/01) STEAM GENERATOR S~SL OPERATIONAL 2 EOC ASSESSMENT 12 (11/01) STEAM GENERATOR Summary of Operational Assessment Steam Generator Predicted to Meet NEI 97-06 Performance Criteria at EOC 13
° Predicted Leakage at MSLB << 1 GPM
- Predicted POB < 0.10 35 SL 2 EOC 12 (11/01) STEAM GENERATOR OPERATIONAL ASSESSMENT CLOSING REMARKS - Raj Kundalkar, Engineering VP Our Operational Assessment Demonstrates:
"*EOC 12 Inspections Provide a Thorough Assessment of S/G Condition
"*The Rate of Increase in Indications is Consistent with Industry Experience
- Strong Assurance of Safe Operation Through the End of Cycle 13 Demonstrated by the Application of a Benchmarked Multi Cycle Model.
Questions?