ML20199G712

Summary of 971023 Meeting W/Util in Rockville,Md Re Results of Steam Generator Tube Degradation & Run Time Analysis for SONGS Unit 2.List of Attendees & Slides Encl

ML20199G712
Person / Time
Site:	San Onofre
Issue date:	11/06/1997
From:	Westreich B NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9711250261
Download: ML20199G712 (58)

Text

&&// bb p t UNITED STATES

} g , *j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30666-0001

%*..,*/ November 6, 1997

]

LICENSEE: Southern California Edison Company (SCE)

FACILITY: San Onofre Nuclear Generating Station. Unit Nos. 2 and 3

SUMMARY

OF MEETING WITH SCE HELO ON OCTOBER 23, 1997 TO DISCUSS THE RESULTS OF STEAM GENERATOR TUBE DEGRADATION AND RUN TIME ANALYSIS A meeting was held on October 23. 1997, between members of the NRC staff and SCE and its consultants to discuss an assessment of steam generator tube  !

degradation and a run time analysis for San Onofre Generating Station (SONGS)

Unit 2. A list of attendees is included as Enclosure 1 and a copy of the  :

slides used by SCE is included as Enclosure 2. The meeting was 1 eld at the NRC offices in Rockville. Maryland.

At the meeting the licensee discussed the steam generator (SG) tube eddy current inspection scope for the upcoming SONGS Unit 2 midcycle outage. One  ;

of the issues discussed was the inspection procedure for dents < 5.0 volts.

SCE plans to use both bobbin coil and rotating probes to inspect dents > 5.0 volts while dents < 5.0 volts would be inspected using just the bobbin coil probe. Since SCE has reported significant degradation at both dented and nondented tube-to eggerate support intersections, and the bobbin coil probe may not be able to identify such degradation at the intersections with low voltage dents, the staff suggested the licensee reevaluate the bases for its inspection plans for dents < 5.0 volts. 4 SCE also discussed the bases for concluding that operation of SONGS Unit 2 through the end of January 1998 is acceptable in terms of maintaining adequate SG tube integrity. The licensee's runtime analysis used a probabilistic i methodology to treat various uncertainties with respect to SG tube degradation (e.g., initiation times, growth rates, probability of detection, burst and leakage values, etc.). The runtime analysis was submitted for staff review on September 25, 1997. Because a complete review of the September 25 submittal may take several months, the staff plans to include in its review of the licensee's runtime analysis a more qualitative, deterministic methodology based primarily on the most recent SG tube eddy current inspection results in i situ pressure test results and laboratory examination of several SG tubes I Woj 3100 PdE CRTm enny F

. w M 3 lllllll1,1ll1,lllj ll 9711250261 971106 PDR ADOCK 05000361 P PDR

r= .

4

• t removed'from SONGS-2 during Gle recent outage. The staff expects additional i questions will_ arise during the course of- the-review pertaining to past _'

inspection results, future inspection plaris (e.g., inspections of dents < 5,0 l volts). and the details of the probabilistic methodology. ,

i Original Signed By i Barry C. Westreich. Project Manager Project Directorate IV-2 Division of Reactor Projects - !!!/IV '

Office of Nuclear. Reactor Regulation Docket Nos. 50-361 )lSTR"BU~ ON: -(w/encls.1 and 2) and 50 362 ( 362et.M eza PUBLIC Enr.losures: 1. Attendance List PDIV 2 Reading -

2. SCE Slides B. Westreich M. Fields P, Gwynn, RIV K. Perkins, RIV/WCF0 DISTR'BUTION: (w/ encl. 2) '

5. Co' lins (SJC1)

F. Miraglia (fJM) i R. Zimmerman (RPZ)

E. Adensam (EGA1) t W. Bateman (WHB)

E. Peyton (ESP)

, r j

l DOCUMENT NAME: 50102397.MTS [

OFCJ PDIV-2/PM PDIV-2/LA NAME- BWestreich EPM @

DATE $L/'//9/ 10//o/97 0FFICIAL RECORD. COPY 4

+

6 W

\{

4 3-cc w/ encl: _

Mr. R. W.:Krieger. Vice President _ Resident Inspector / San Onofre NPS Southern California Edison Company c/o U.S. Nuclear Regulatory Commission San Onofre Nuclear Generating Station Post Office Box 4329 -

P. 0.. Box 128 San Clemente. California 92674 San Clemente. California 92674-0128 Mayor Cbirman. Board of Supervisors City of San Clemente County of San Diego 100 Avenida Presidio 1600 Pacific Highway. Room 335 San Clemente. California 92672 San Diego. California 92101 Mr. Dwight E. Nunn. Vice President Alan R. Watts. Esq. Southern California Edison Company Woodruff. Spradlin & Smart San Onofre Nuclear Generating Station 701 S. Parker St. No. 7000 P.O. Box 128 Orange. California 92668-4702 San Clemente. California 92674-0128 Mr. Sherwin Harris Mr. Harold B. Ray  ;

1 Resource Project Manager Executive Vice President Public Utilities Department Southern California Edison Company l City of Riverside San Onofre Nuclear Generating Station 3900 Main Street P. O. Box 128 Riverside. California 92522 San Clemente. California 92674-0128 Dr. Harvey Collins. Chief Division of Drinking Water and Environmental Management California Department of Health Services P. O. Box 942732 Sacramento. California 94234-7320 Regionai Administrator. Region IV U.S. Nuclear Regulatory Commission Harris Tower & Pavilion 611 Ryan Plaza Drive. Suite 400 Arlington. Texas 76011-8064 Mr. Terry Winter Manager. Power Operations San Diego Gas & Electric Company P.O. Box 1831 San Diego, California 92112-4150 Mr. Steve Hsu Radiologic Health Branch State Department of Health Services Post Office Box 942732 Sacramento. California 94234

, ATTENDANCE LIST OCTOBER 23. 1997 SAN ON0FRE NUCLEAR GENEPATING STATION STEAM GENERATOR INSPECTION PLANS NRC/SCE E

Mei Fields Cheryl Beardslee Rich Emch Andrea Keim

. Barry Westreich John Tsao - -

Stephane Coffin ABB-CENO John Hall APTECH Enoineerina Steve Brown Jim Begley Brian Woodman Christopher Begley Bft&E Anthony Saccavino Southern California Edison Jack Rainsberry Dwight Nunn Mike Short Al Matheny-

Assessment of Steam Generator Results Southern California Edison Company Cycle 9 Refueling Outage (1997) ,

~

San Onofre Unit 2 [

October 23,1997

/

TOPICS . .

Introc uction

?ulled Tuae Results .

- Supplemental Performance Demonstration Concition Moni':oring Assessment Operationa. Assessment Operational Enhancements and Inspection Summary i

3 TSTRODUCTION

. Objective: Present fo ow-up information anc.

assessments ofinspection resu ts t Time. ine - San Onofre Unit 2

- Dec 96: Chemical Cleaning .

- Jan 97: Inspection & SCE/NRR Meeting *

- Feb 97: In-Situ Testing / Tube Pulls

- Feb 97: SCE Special Report to NRC (Commitment for Follow-up Report)

- March 29: Restart of San Onofre Unit 2 ,

- Sep 97: SCE Follow-up Report to NRC

- Jan 98: Mid-cycle SG Inspection

- Dec 98: Refueling Outage

INTRODUCTION Assessment GuicLance Source.s

legulatoly Guic e 1.12:.

Generic Letter 95-05 Draft : leg Guic.e X.XX (SG Tu 3e Structura Integrity - Novem aer 1996) l EPRI SG : Examination Guidelines

3PRI SG Secondary C aemistry Guic.elines

3:?R~ Prima 17-Seconc aiy Leat Monitoring Guide _ines

~

PULLED TUBE FWSULTS Introduction -

Pulled 3 :uaes in Fe3 97

- C;aaracterizec axial crac ting in Freespan Supplemental performance demonstration of bobbin technique t

- C;aaracterizec axia crac1ing at dentec &

unc ented eggerate locations

- Burst / Lea 1 testing of 18 segments of tu aing

- Destructive exam c.epta measurements at 55 cifferent axia. .ocations ,

t .

~,

.m a

~

PULLED TUBE RESULTS i Axial Cracks in Freespan Tubing i .. . . .

a . R94C32 and R16C164 in SG 89 1 Outside Diameter (OD) initiated degradation -

Axial crac1ing in freespans between 4H and 7H eggerates - max c epths <38% throughwall Many snort, shal: ow inc ivic ual axia. cracks Leak / Burst testing of 3H to 7H I

^

- No leakage .

-- Burst pressures consistent-with unflawed tubing -

y n

l.:

~ . . -

?- ,

PULLED TUBE RESULTS 1 .

Axi~al Cracks in Freespan Tubing Supplemental Performance Demonstration l Purposes met

[

- Demonstrated Bobbin Probe detection capabilities

- Quantitative detection input for Condition Monitoring

& Operational Assessments j All " graded units" had destructive exam (metallography or fractography) i 4

Results from 5 teams Each team had 4 analysts in conventional roles &

reporting structure 1 m

PL'LLED TC~BE RESELTS Axia Crac1s in Freespan Tubing Supp.ementa Performance Demonstration Bobbin Probe n

1 7 g _ m- ,-

, 0 X

n 0.8 ,

TeamA [/ ,o' sg +TeamD .  :

x 0.6 jl r y 2 -K h TeamC

• jO ,

.g 4 TeamD 0.4 f/

o x ', g TeamE 9,'

~O 0.2 j 0 20 40 60 80 100

= 4 . :  :.: n . , ectw $l

p,.,.

PULLED TUBE RESULTS

~

Axia Crac1ing - Jentec Hot eg Eggerate R94C32 @ 4H in SG 89 (6 vo_t c ent by aobbin)

NDD ay 30 3 ain in arevious refueling outage,97 review concurs, aut smal; 91aw may ae present Insic e Diameter (ID) initiatec c egradation -

Max t;aroug awa. c ept: 1- 93 %

4 No eacage at MSLB l -

5300 asi aurst pressure l

s 6

l t i I

r i

PCLLED TC$E RESLLTS Axial Cracking - Undented Hot Leg Eggerate R61Clli @ 7H in SG 89 NDD by bo 3 bin in previous refueling outage,97 review Concurs Inside Diameter (ID) initiated degradation Degradation area damaged during tube pulling.

1.35 gpm leakage at MSLB 3515 psi burst pressure 1

IX-SITU PRESSURE TESTING I

- Axial Crack - R13C117 @ 6H in SG 89

- 24 volt dent

.NDD by bobbin in previous refueling outage,97 review '.

concurs, but small flaw may be present

- 0.24 gpm leakage at MSLB

- 3150 psi at max test makeup capacity

- 20 other tubes in-situ tested

- No leakage

- Structural integrity met 1 -' --

,, ii-

CONDITION MOXITORING .

Com aination of eddy current testing, and pullec tu ae & in-situ pressure testing provides data for comparison with Condition Monitoring .

performance criteria

4 ."

4 it i

OPERATIONAL ASSESSMEST .

a t

l Dr. James Begley

- APTECH Engineering Services

(

l t

i I

i  !

4 I

i I7

./' HE REgMggggg IS APPLIEDTECHNOLOGY n!!3 t

a ,

+

, AN OPERATIONAL ASSESSMENT E OF STEAM GENERATOR TUBE-

, DEGRADATION AT SONGS UNIT 2 FOR CYCLE 9 e

C. J. Begley B. W. Woodman J. A. Begley ,

S. D. Brown APTECH ENGINEERING SERVICES, INC.

PITTSBURGH OFFICE Prepared for Southern California Edison Company San Onofra Nuclear Generating Station San Clemento, CA 02674 l

APTECH ENGINEEPING SERVICES. INC.

t .

200 FLEET STREET 3 SUITE 4410 c Pf1TSBURGH :: PA 15220 e (412) 920 C633 o FAX (412) 920 6644

.f .

HEADQUARTERS o SUNNYVALE. CA o (408) 745-7000 oFF10ES C UPPER MARLBoRO. Mo o (331) 599-2301 c CUMM!NG. nA :(770) 7813756 0 BIT 7HLEHEM, PA 0 (610) 866 7347 HOUSTON. TX c (713) 556-3200 C CHATTANOOGA. TN O (61.) 493 3777 c GASTONIA. NO (704) 265 6318

. . i

E(APTECH;

, ;g m.m m IDGR SIMULATION MODEL

• INITIATION GROWTH DETECTION SIZING REPAlR

• REPEAT FOR MULTIPLE CYCLES OF OPERATION

• BENCHMARK MODEL COMPARE PREDICTED VERSUS OBSERVED NUMBER OF INDICATIONS

- DISTRIBUTION OF EOC DEPTHS, LENGTH, ETC.

• PROGRAM KEEPS TRACK OF DETECTED AND UNDETECTED CRACKS

• PROGRAM SIMULATES "REAL" CRACK SIZES

• "REAL" AND " MEASURED" CRACK SIZES ARE FOLLOWED e EOC CRACK SIZE " MEASUREMENTS" ARE PREDICTED e BURST AND LEAK CALCULATIONS BASED ON

, "REAL" SIZES OF BOTH DETECTED AND UNDETECTED CRAvKS 15

y t

g{gpugf

= v IDGR MODEL DEVELOPMENT 7 N A c APPLICATION -PROBE BENCHMARKING CRITERIA -

^'

Freespan Axial ODSCC RPC Number of Indications 3AP-o Erransion Transition i 1 Circumferential Degradation RPC Number of Indications . _ 3AP s

Eggcrate ODSCC Bobbin Number of Indications 3AP Freespan ODSCC x Plus Point Number of indications with '

SLB Inspection Transient, Notable /,

Operational Occurrence 1 i

Eggcrate ODSCC . Bobbin Number of Indications, SLB-

! Number of Deep Cracks, t in Situ Results 1 i

l Freespan ODSCC Plus Point EOC Distribution of Voltages SLB  :

.i Eggcrate ODSCC Bobbin Operational Occurrence,- SLB Number of Indications with Inspection Transients, EOC Distribution of Depths  !

Present RPC, Plus Point, Pulied Tube, in Situ Results, SLB Bobbin Maximum Crack Depth, EOC l PDA Distribution .

4 tG

$EiRPTECH; NEIRING LERUCE5. IT

,- .EM SONGS UNIT 2 SG 89 FREESPAN OD INDICATIONS, PLUS POINT .

VOLTAGE 99.9 %

l 99.0% -

e 90 % I i '/ Ft.,9dr O say, I I ll l l l_ I (( l l l lllll 70 %

I  ! IW I I I I III!!

60%

I I III!! i l II l l[I' l l l l l llll 50 %

I I I IIII I I EIlY II' l l ' l l llll o gy, I l I l lllll l f I l/ ill i l l l -l l llll 30 %

ll

$ 20%

g /

j 10% e ' -

m 5%

is .

2 E

a 1% l 0.5%

0.1% *

• 0.01 ' ' ' ' ' ' 'o,1 * ' ' ' ' ' ' ' '

1.0 10,0 PLUS PolNTVOLTAGE, VOLTS 17

d 4 4 . p EjAPTECH!'

E u 86iniso scavecs. iNc.'

f 1.0 Plus Point ic.

0.8 RPC 0.6

-li ,

2

.5 g OA' w.

- 0.2 0.0 0- 20 40 60 80 100

- Average Crack Depth, % Through Wall Ih

=

A. A A g

.g , / wv ye s dst U 3

=

Lst >

m<

o.

oo 02 04 os rd to u 14 ta cracklength

(*)

Mk f3 n

. IU8X

.c

,E~ " t t,

c=

"z

< Lst >

v

= c2 e o. a so a u ,.

cracklength (b)

Figure 2.1 Idealized Crack Profiles for (a) Burst and (b) Leakage.

Aptech Engineering Services, Inc. AES97043057-1 13 .

(h

Maximum Depth versus StructuraDy Significant Depth 100  ;  ;  ; -- .

o s 90 .- 4 .

+4 80 -

+

+4 +

y

+ +- +

+ +

+

g M' , +

so .

n .0 . .

+

30

+ +

20 10 0

0 10 20 30 40 50 60 70 80 90 100 Stramart! Depth, %1W Figure 2.2 Maximum Depth Versus Structurally Significant Depth, Pulled Tube Data, Aptoch Engineering Services, Inc. AES97043057-1 14

}

2O

i L

s<

hPI < Li ,, >

d mtX Jk t

d,

< L, y l v v v Figure 2.3 Idealized Leakage Crack Profile after Through-Wall Penetration Aptoch Engineering Services, Inc. AES97043057-1 15

,Q\

14000 m ANO UnN 1 e ANO Unit 2 ga

& APS PV Unit 2 _,

12000 --

• BV Unit 1 ,'

acc Unit 1 ,

a CONS Unit 2 c, a SONGS Unit 2 8

10000 1 4 U I

f 8000  :*

a

• 2 A

AA o,

, og m

l o o

So '

4

} 0000 v O,

$ 0 0

o .s <3 aA e oA U

l 60

+

4000 a,

i A 2000 e l 4 l

0 0 2000' 4000 6000 8000 10000 12000 14000

! Measured Burst Pressure, pal l

l l-l Figure 2.4 Calculated Versus Measured Burst Pressure Using the Structural Minimum Method and the Frarnatome Burst Equation.

Aptech Engineering Services, Inc. AES97043057-1 16

-21

.100 f s l

10 l}

11 -~~ _

g a F:

f6l

/ .'

1 f

.Y '

~

f6/

h'?'.* ,

/ <T .-

g //.%o h

[Y .-

', .. ~

' , " ' ,G

. .f. . - o o

.' O. .

0.01 j

3. - ..; -

,, :' u i  !

j,*' s a e

,.. ~~

,r 0.001 , ^- 0 ~~"""W FATIGUE CRACKED DATA

"""0.875* OD BY 0,050" WALL

- " 0.750' OD BY 0.043* WALL

~

O CEGB SCC

• CEGB FATIGUE CRACKED DATA 0.0001  : ::

O.1 1 CRACK LENGTH, INCHES Figure 2.5 Calculated and Measured Leak Rates for Axial Cracks in Alloy 600 Tubing at Normal Operating Conditions.

- Aptech Engineering Services, Inc. AES97043057-1 17 .

23 7

, so

'f

.nn

. Burst occurs by axial tearing "

before ci.htlal failure. BW pressure ggesd by l k the tensile capability of the <=

remaining ligament area.

• Typical of 360* partial depth cracking.

J!.

COD Measurements '  !

4 \

i Transition region bdww.

> I bending and tensile mode of L

rupture. Distrs%: tion of RA ,

l! !  ! l.  ! sigmif:.w.:Iy affects the l

g 3

$ p@-g!g' burst guessmo. '

i '( ,

b . .

I( -i N(

! fi t h i i

1 i r  ;

iiE_-' _ -  !

g Burst pressure go__-__a

== by g

A the bending capability of the

=3 l3,*g"""  ;

i

-i gg m w i,  ; pi remaining Ilgament area.

' Typical of largely throughwall cracks.

,,%lIjk, [M66 m .

c \ _

Critical ragion for ARC- i

, GEER i=

j 0.0 0.5 1.0 f$  !

F 9 a mt Percent Degraded Area E ct F 2.

i

+ + , v + +'-

2000 1600 -

1600 1400-

' 2= , y E

d $N

$'1000 i

(

5E

' l

.}..

8"-

lg gne 8  ::: n1

{- n -

.i 4"~

M w: P !s k

--  ! ?g h .

b!bf -

1. r"g '

'l l li 1 W 0

110 115 120 125 130 135 140 145 Yield + Ultimate Strength (ksi)

Figure 3.1 Histogram of Tube Strength Data for SONGS Unit 2, Steam Generators 88 and 89.

Aptech Engineering Services. Inc. AES970430571 2$

1 ~

4 0.0 -

-i 0.6 2 l

u. i I

j Measured Distribution m

E y 0,4 -Log-Norrnal Fit i

0.2 }

O O 0.2 0.4 0.6 0.8 1 1.2 Axial Length, Inches Figure 3.2 Distribution of TTS Axial Crack Lengths.

Aptech Engineering Services,Inc. AES97043057-1 2b-

1 0.8 f0.6

b. I u.- /

/ Measured Distribution 0.4 -Log-Normal Fit 0.2 I

' 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 Aximi Length, Inches F!gure 3.3. Distribution of Eggerate Axial Crack Lengths.

Aptech Engineering Services, Inc. AES970430571 S)

- - . . _ . - _ . - . - . . - - - . - - - - - _ =_.

i 1.0 Plus Point 0.8 RPC 0.0 B

I 0,4 g

0.2 0.0 0 20 40 60 80 100 Average Crack Depth, % Through Wal!

Figure 3.4 Plus Point and RPC Probability of Detection for Axial Degradation as a Function of Average Crack Depth.

Aptech Engineering Services, Inc. AES970430571 26 ,

- hk

1.0 g-0.8 Plus Point RPC 0.6' 15 0.4 0.2 0.0 0 20 40 60 80 100 ,

Percent Degraded Area Figure 3.5 Probability of Detection Versus Percent Degraded Area for Circumferential Cracking (TTS).

Aptoch engineering Services, Inc. AES970430571

.7k-

t t

, , ,, ,, = * * ",";5

. *, # ,<# j t' .

./

i

,. ,/

/ /

os-  : *  ;

/  ;

l i i '

i

. .t l .

l i I

l '

I o.6' l

L l I l

l'  !

l 1 I

o4- ,e ,i l

• I l

. .I l I l

• j freespan o.2 -

!  ! """eggerate. undented l I I

j j - -* eggerate, dented

. /

.. ,.* ,/

o 0.2 0.4 os oa 1 average depth (TW fraction)

Figure 3.6 Probability of Detection Functions for Bobbin Probe, Adjusted for Eggcrate Region and Tube Denting.

Ap'ech Engineering Services. Inc. AES970430571 20

~fQ1

1.0 f

/ l i

0.8 i

. 0.6 u.

0.4 o i 0.2 0.0 10 15 20 25 30 0 5 circ Crack Growth Rate, PDA/EFPY

(

Figure 3.8 Distribution of Circumferential Crack Growth Rates Used in Probabilistic Analysis.

4 AES970430571 Aptoch Engineering Services, Inc.

$\

, ,rw.,,,,,,,,. , - -,, , , , - - - . + r -- - , , . - - ,

4 0

1 0.9 - -

0.8 - -

2 0 -

h .7 --

O g 0.6 - -

g ._

0.5 --

0.4 --

p (

3 8 o3 : I 0.2 --

0.1 --

0 ,

0 10 20 30 40 AXIAL CRACK GROWTH RATE, %TW/EFPY Figure 3.7 Distribution of Axial Crack Growth Rates Used in Probabilistic Analysis.

-s- Aptech Engineering Services, Inc. AES970430571 3%

EEIRPfECH'

.. amwaa AVERAGE CRACK GROWTH RATE MEASURED DEPTH = ACTUAL + MEASUREMENT DEPTH ERROR 1

M, = D, + E , l l

I Mi = D, + E i GROWTH = D, - D i M, - Mi = D, - Di+E,-E i AM = Growth + E, - E i If E, and E are i normally distributed with a mean value of zero, then:

I E, = 0 EE=0 i EAM = Average Growth Rato n

3

$2!APTECH y,y y m m o c .

100 l

90  :

80 .

70 j 60 X

8 50 S

X o

m 40 e

30 - - .

• e l

20 .3,#

o e

e 10 e_

o e e 0

0 10 20 30 40 50 60 70 80 90 100 BOC actual 39

" RPTECH'

.Ermumuur 100

(

80 " -

i Il ll 60 ll .

40 6  ;

n ..

1o g .' .

.s el .

l 20

• H.'

. e*- . 1 E

o .T o

m . On ,

. .l. % e . *l . f *.

i 1 .

i .

• s. ..

.R . t . . .*s ,. .

E 20 'e *

I.*.

.i g ., . . I w

-40 -' i' i

-60

• t

-80 100 0 10 20 30 40 50 60 70 80 90 100 BOC measured 35

$dAPTECHI*

=~ -mr.m?.

50 45 .

40 35 ~

30 I25 1

- 20 15 10 - --

4 5

0 0 2 4 6 8 10 Signal to Noise Ratio

3W

. ESRPTECH'

• A g;*rraTirstrwd

\ /. \

\ }/ j

\ l

\,

\\ /  :

1 /

< \ /

1 \k

\ /

/

/  :

\

/

. s g i

L \\

/

/

{

\ j 6 4\ /

/

\ g

\

g /

\ /

g

\ /

k /

's,% y/

l Time Schematic of Laboratory Test Results ABB-CE / Aptech CEOG Axial Crack Program 3} .. . . - . -

EEAPTECH

.v.ww.

.: .e : . a . .

Steam Gonorator A, Channel P1 100 li e

8Q . . . - .

- . _ _ . . _ _ . _ . . _ . ~ . . . . _ _ . - _.._._ _ _

9 e

() . . . - . -. . . - . - . . .

ii .

O b 4 . , ,~.

9 ll . * ,

• e n .

b w w *

• 6 20 f g g g g -e-'* -

e e

. .. t6 e m s rt *s * #

• e e

e e e e

m 0' **

p: Ot  % 66 -

• e9-e * *-e *~* * *

>4 .

• ee e e-*

• * . *

• A. . %e g e e*e*e o e e es, ,*

.:e-

. t -

e

--e. -

o o

, e e t

4Q .- . --- -

y e

• • e o

-60 - - - - - - - - - - - - - - - - - - -

e

,3; ..

300 . _ _ ..

O i. . . . .. 30 70 EO ED 100 7,'I'.% 95 3B

APT Mmmm.idi'

.. .m. ,c  :,

em ,

i

, i

.I a- Channel P1, >=0.6 Volts l 100 i

i 4 , .

l~ i 1

, , 4 80 - - -

i  :

I 1

, .1 i

60 -

I '

! l i i

i f f ,

i l 40 , _ . .

o <

i  !-

, e i e

o e >

i '

20 D -- =

o  ; e e ,

i

m. e ,

m-

• e e. , e . >

m 1 i e !j i '

On e

4 e e ,

og o. e e e

• tt  :'

< i i *

}

l l t i 20 .- ,  ; e .

r i l,  : 1 6

i I

A l

}  !

-40 I i I

i 1 60 i

}

80 - - - - -

4 l l 1

'  ; n 100 O 10 -20 30. 40 50 60 70 80 90 -100

% TW,95 i, ,

(

I j.

i-13ep

.' $APTECH;'

j%gumn.itit int 99.9 %

99.0%

l l l l lll So%

I 1

/

Y l[ d[/[

/

l l l l l lll seg  ! Illll I IN -M I I l 7o%

1 8 / l/ ' # I i i i iisii so%

50 %

' l/ l /!# II I I I I IIIil o a .I / /l/ ll l l l l l l lll I"l M lIi l l l l l l llll h 3o%

l ll hm w

l ll 2

10% -

t sw i

1%

0.5%

01% . . . . . . . .

to 100 i

enAcx onownf RATE.%TW/EFPY AXIAL DEGRADATION GROWTH RATES, ODSCC/lGA 10

G!!APTECH' -

.re:nnmturgrrvd a~

Circumferential Crack Dotorministic Analysis 100 ,

00 -

80 =-

3AP Limit 4 70 60

$ 50

n. j i l 20 PDA / EFPY l

l 30 I

20 10 0

0.0 0.5 1.0 1.5 2.0 Time, EFPY l 1

. EiAPTECH'l runwim.us.x: l o-Axial Crack Deterministic Analysis l t

i 1,00  ;

0.90 -

e 0.80-  !

,MP Limit 0.70 -

L=0.70 /

7, .

t i / L /

L=1.05 0.60 --- -

I g 0.50 -

> 20% TW / EFPY 0.40 i

0.30 0.20 -

0,10 - ,

0.00 0.0 0.5 1.0 1.5 2.0 Time, EFPY b---

~

. .~ . . . _ _ __ .__ . . .. __..._..___.._-____.__.:_.___._ _.~ _,. -. .

1

,.'t .

W APTECH'

.a-% m w . c s.a.c:

10 i

E3 detected + measurement error 1

umeasured cire cracks j

i. .

E 8 '

3

]

5 . .

x -

i

, E-

=

. a 4

3 .

l h.

I nm

( -

0- 1 0.05 0.1 0.18 0.2 0.23 0.3 0.35 0.4 0 45 0.8 0.55 06 0.85 0.7 0.75 0.8 0.85 0.9 0.95 pda Figure 5.1 Comparison of Actual Measurements and Predicted Measurements for Circumferential Degradation PDA Values at the Top of Tubesheet, EOC 8.

Aptoch Engineering Services. Inc. AES970430571 43 3

- '5APTECHf i-

• k

. _t # c a u r a ts t .

Predicted vs. Actual Bobbin Depth Distribution 1

1 v

0.8 f

i g of.

X k i

.I 33 1

u OA

! i actual bobbin depth i 0.2 + predicted bobbin depth Sctns (UIT 2 0

0 0.2 OA 0.6 0.8 1 bobbin depth (fraction TW) 1

(

, .. 1 f

.i .g

- r i TABLE 5.1 i 7  :

}

~

l SONGS UNIT 2 i

} } COMPOSITE WORST GENERATOR l

EDDY CURRENT INDICATION HISTORY

! s. i

. o -

i y DEGRADAT'ON MECHANISM  !

! =r

EFPY TOP OF TUBESHEET TOP OF TUBESHEET FREESPAN UNDENTED DENTED !

CIRCUMFERENTIAL AXIAL AXIAL EGGCRATE EGGCRA1I l (ODSCC & PWSCC) (ODSCC & PWSCC) (ODSCCAGA) AXlAL AXIAL l (ODSCCllGA) (PWSCC) i I  !

(NUMBER OF INDICATIONSIEDDY CURRENT PROBE) 7.17 10lRPC 11RPC - OIBOBBIN 3/ BOBBIN OlBOBBIN 8.63 12/RPC OIRPC O/ BOBBIN 2/ BOBBIN OlB O BBIN !

10.05 43/PLUS POINT 91/PLUS POINT 441GOBB1tc 7/ BOBBIN BIBOBBIK L i

i PROJECTED' .

R. 10.97 101 32 63 7 8 l $ 12.05* 250 78 - - -

1 2 w l.

2 8 ' Average projection result  :

y 2 Without mid cycle inspection i

_ _ _ _ ._, _ ~ . . . _ _ _ _ .. - _ . _ _ _ _ _ _ . _ . .

e TABLE 5.2 l

SUMMARY

OF STRUCTURAL MARGIN AND PROJECTED SLB LEAK RATES i PROJECTED FOR 11.01 EFPY '

(Mid Cycle)

Degradation Mechanism Conditional Probability of _95/95 Leak Rate at l Burst at Postulated SLB Postulated SLB (95% Confidence Level) (GPM at 600'F)

Axial ODSCC at Undented Eggerate 0.0008 0 Intersections '

Axial PWSCC at Dented Eggerate Intersections 0.0096 0.0044 Freespen Axlal ODSCC 0.0003 0 Circumferential ODSCC/PWSCC at 0.0003 0.028 ppansion Transitions Axlal ODSCC at Expansion Transitions 0.0005 0 PROJECTED FOR 12.09 EFPY

' WITHOUT A MID CYCLE INSPECTION ,

Degradation Mechanism Conditional Probability of 95/95 Leak Rate at '

Burst at Postulated SLB Postulated SLB (95% Confidence Level) (GPM at 600'F)

Circumferential '

ODSCC/PWSCC at 0.0005 0.38 Expansion Transitions Axial ODSCC at-Expansion Transitions 0.0033 -0.009 i

Aptech Engineering Services. Inc. AES970430571 44

ESAPTECH g:gramad i

SUMMARY

e COMPARATIVE ANALYSIS

• DETERMINISTIC ANALYSIS

• PROBABILISTIC ANALYSIS

. SUPPORT FULL CYCLE OPERATION FOR TTS DEGRADATION .

e MID CYCLE BOBBIN INSPECTION Lf7

~

ENHANCEMESTS Operation

. Planning to ower reactor coolant temperature by 13 degrees to reduce tubing corrosion 9 .

v

{. e' EXHANCEMESTS ,

Secondary Chemistry Control Chemical Cleaning (full-bundle) - Dec 96 j Re-convened panel ofindustry experts in Feb 97 and Sep  :

! 97 to evaluate inspection results & corresponding chemistry considerations Titanium Dioxide added right after Chemical Cleaning

(inhibit IGA / SCC)

Ethanolamine (ETA) implemented to minimize corrosion L product transport & deposition on tubmg I -

Planning plant modifications for boric acid addition

! (inhibit denting & SCC) 4 l

..c qq

• L ,

u L

INSPECTION - AXIAL PWSCC

! Indications at Supports l

3 indications were detected during the bobbin exam t

L Plus .30 int exams i - Approx. 8,300 hot leg eggerate supports 1 l (4 indications at c ented supports) l - Approx. 7170 diagonal and vertical strap

) supports (No indications)

! i t

i-

^

I, G-

INSPECTION Mic-Cycle inspection ou: age

- 100% Bobbin exam -axial cracing at eggerates  ;

- P; us-Point exam -

Axial cracking at dented eggerates All row 1 & 2 u-bends t Normal follow-up ofinconclusive bobbin data Hot leg top-of-tubesheet exam NOT planned

- In-situ testing, e.g., largest PWSCC

- Visual exam of eggerate tube supports al

SAN OXOFRE UNIT 2 Summary Numerous en lancemeir:s to minimize c egrac.ation Guic.ance used to quantitatively assess / 3 rec.ict tu 3ing per:formance  !

San Onofre Unit 2 Vid-cycle ins;3ection p_an provic es assurance of satisfactory

~:u aing ;3er:formance throughout cyc: e 9 0;3eration c- c.,

p - - - --

SAN ONOFR3 EKIT 3 Mid-Cyc~ e Ou: age Planning Visua exam of eggerate tuae supports Ec cy Currerr: bob 3in pro 3e exam of a sampling o:Ptubes to moni:or tuaing wear a

M . P,