ML13319A718

From kanterella
Jump to navigation Jump to search

Summary of 800710 Meeting W/Util in Bethesda,Md Re Results of Steam Generator Insps & Corrective Actions
ML13319A718
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 08/08/1980
From: Nowicki S
Office of Nuclear Reactor Regulation
To:
Office of Nuclear Reactor Regulation
References
TAC-42090, NUDOCS 8009020448
Download: ML13319A718 (50)
v • d • e


Text

REGULATORY D0KET FILE COPY Docket No. 50-206 Gj 0 9 LICENSEE: Southern California Edison Company FACILITY: San Onofre Unit No. 1

SUBJECT:

REPORT OF JULY 10, 1980 MEETING TO DISCUSS THE RESULTS OF STEAM GENERATOR INSPECTIONS AND CORRECTIVE ACTIONS FOR SAN ONOFRE UNIT 1 NRC and Southern California Edison Company representatives met in Bethesda, Maryland, on July 10, 1980, to discuss the ongoing steam generator tube inspections at San Onofre Unit No. 1. The meeting attendees are listed in.

SCE requested the meeting to present the results of their inspections and discuss additional investigations.

The results of their investigations with a more sensitive eddy current probe indicate about 1/4 of the tubes examined have indications of cracking above the 50% penetration plugging limit.

Less than 150 man rem exposure was accumulated since the steam generator inspection began during this current outage. The additional investigations will include further eddy current testing, removal of five additional tubes for more detailed examination, primary and secondary side pressure testing of the tube bundles, and an investigation (including secondary lwatpr chemistry) of operating conditions. It is expected that the facility will remain shut down through August.

The licensee provided handouts of the presentation; this is included in.

OrigiI

  • od bY Stanley J. Nowicki, Project Manager Operating Reactors Branch #5 Division of Licensing

Enclosures:

1. List of Attendees
2.

Presentation cc w/encl:

See next page 8009020448 DL:OR O F F ICM E

. o... b.

s u R N M E........

DATEO8/7/80 NRC FORM 318 (9-76) NRCM 0240

  • U.S.

GOVERNMENT PRINTING OFFICE: 1979-289-369

LIST OF ATTENDEES NRC Southern California Edison G. Lainas B. L. Curtis D. Crutchfield H. L. Ottoson B. D. Liaw R. W. Krieger W. J. Collins K. P. Baskin A. Burger E. J. Brown V. Benaroya E. Murphy D. T. Huang R. Emch B. Turovlin L. Frank V. Noonan BNL J. Weeks D. van Rooyen Westinghouse T. R. Timmons W. D. Fletcher R. T. Beglen D. D. Malinowski E. P. Morgan C. Lissenden, Jr.

J. L. Houtman C. W. Hiast O FFICE T...

SURNAME DATE

..... I NRC FORM 318 (9-76) NRCM 0240 U.S. GOVERNMENT PRINTING OFFICE: 1979-289-369

Meeting -Summary Distribution Southern California Edison July 10, 1980 Meeting Docket File NRC PDR Local PDR ORB#5 Reading NRR Reading H. R. Denton E. G. Case D. G. Eisenhut R. A. Purple J. Olshinski T. Novak R. Tedesco G. Lainas G. Zech J. Heltemes, AEOD S. Varga T. Ippolito R. Reid R. Clark B. J. Youngblood A. Schwencer J. R. Miller Licensing Branch #3 D. Crutchfield Systematic Evaluation Program Branch Operating Reactors Assessment Branch S. Nowicki OELD OI&E (3)

H. Smith ACRS (16)

NSIC TERA NRC Participants

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 August 8, 1980 Docket No. 50-206 LICENSEE: Southern California Edison Company FACILITY:

San Onofre Unit No. 1

SUBJECT:

REPORT OF JULY 10, 1980 MEETING TO DISCUSS THE RESULTS OF STEAM GENERATOR INSPECTIONS ANDCORRECTIVE ACTIONS FOR SAN ONOFRE UNIT 1 NRC and Southern California Edison Company representatives met in Bethesda, Maryland, on July 10, 1980, to discuss the ongoing steam generator tube inspections at San Onofre Unit No. 1. The meeting attendees are listed in.

SCE requested the meeting to present the results of their inspections and discuss additional investigations. The results of their investigations with a more sensitive eddy current probe indicate about 1/4 of the tubes examined have indications of cracking above the 50% penetration plugging limit. Less than 150 man rem exposure was accumulated since the steam generator inspection began during this current outage. The additional investigations will include further eddy current testing, removal of five additional tubes for more detailed examination, primary and secondary side pressure testing of the tube bundles, and an investigation (including secondary-water chemistry) of operating conditions. It is expected that the facility will remain shut down through August.

The licensee provided handouts of the presentation; this is included in.

Stanley J. No icki, Project Manager Operating Reactors Branch #5 Division of Licensing

Enclosures:

1. List of Attendees
2. Presentation cc w/encl:

See next page LIST OF ATTENDEES NRC Southern California Edison G. Lainas B. L. Curtis D. Crutchfield H. L. Ottoson B. D. Liaw R. W. Krieger W. J. Collins K. P. Baskin A. Burger E. J. Brown V. Benaroya E. Murphy D. T. Huang R. Emch B. Turovlin L. Frank V. Noonan BNL J. Weeks D. van Rooyen Westinghouse T. R. Timmons W. D. Fletcher R. T. Beglen D. D. Malinowski E. P. Morgan C. Lissenden, Jr.

J. L. Houtman C. W. Hiast

9ttachment 2 SCE -

NRC MEETING ON STEAM GENERATORS JULY 10, 1980 INTRODUCTION SCE BACKGROUND-CHRONOLOGY-ACTIONS SCE INSPECTIONS AND FINDINGS w

TUBE SAMPLE EXAMINATIONS w

PRESSURE TESTS H

SUMMARY

SCE

CHRONOLOGY A.

June, 1979

- Maintinance Outage

1.

Primary to z-.-rndary leakage identified in steam generator A going into outage.

2.

Eddy curr--'

rzpection performed in steam generators A and C.

(A) 639 t in steam generator A hot leg inspected through first

upi'crt plate -

21 plugged due to tube sheet area indicltions1.

(B) 215 tubes in steam generator C hot leg inspected through first support plate - no pluggable indications B.

August, 1979
1.

Westinghouse evaluation of June, 1979 eddy current inspection received.

2.

Recommendations included:

(A) Cycle VIII refueling outage eddy current inspection program in steam generators A, a, and C.

(B) Steam generator secondary chemistry control modifications.

(C)

Suggested tube pulling during Cycle VIII refucling outage.

C.

February -

April, 1980

1. 'Steam generator leakage observed steady at 40-60 CPD follouing TML. outage
2.

Steam generator leakage begins to accelerate, reaches approximately 260 GPD on April 8, 1980.

D.

April 8, 1980 Unit shutdown due to steam generator primary to secondary leakage.

E.

April 13, 1980 - Steam Generator Secondary Side Hydro.

1.

Steam generator C -

5 leaking tubes indentified.

2 Steam generator B - 3 possible leaking tubes identified.

3.

Steam generator A -

1 possible leaking plug identified.

4.

Steam generator, C -

5 leakers plus 2 adjacent tubes eddy current te:fted by hand.

All tubes indicated 99%-100' through wall degradation at top of tube sheet (TTS).

F.

April 28, 1980 - '.:!utinghouse/SCE Meeting in Pittsburgh

1.

TTS expr' inrg apparent corrosive attack to extent not previousv cbed

2.

Eddy currn::

dipection program expanded to include all tubes through i

. upport plate on hot legs of steam generators A, B, and C.

3.

Selection of tubes to be pulled for examination dependent upon eddy cur;

-esults.

G.

June 18,. 1980 P:';.Ating with NRC Staff and Westinghouse/SCE personnel to present findings of chemistry program review, eddy current data evaluation, removed tube metallurgical examinations and revisea inspection program H.

July 10, 1980 Meeting with NRC staff and Westinghouse/SCE personnel to present revised inspection program

II.

FINDINGS A.

Chemistry Program Evaluation Evidence of high ratio phosphates and possible free caustic intermittently since mid-1978.

B.

Eddy Current Inspections

1.

Extensive confirmed tube wall degradation at TTS in hot legs of all steam generators (~400 pluggable tubes).

2.

Possible extensive unconfirmed tube wall degradation at TTS in each steam generator (complex eddy current signals for-wl130 tubes).

C.

Metallurgical Examinations of Removed Tube Specimens

1.

Caustic induced intergrandular attack (lGA) occuring nearly through wall in specimens from tubes R2LC71 (95% TTS indication, 26%

indication -11" above TTS) and R31C28 (complex eddy current indication at TYS).

2.

IGA and cracking observed in tube sheet crevis of tube H17C52 (95% indication.'!" below TTS in tube sheet crevis).

3.

IGA not readily detected and quantifled by standard cddy current coil.

).

IG T

p iously oboserved in co4estro anZa foreig

.PWR's.

1.

Eddy current inspections with new surfacc coil pancake) prc.u.

(A)

In-pot 1! tKes relected for remova from steam. ener:ator C with nancake crobe to provide correlation data prior to tube removal.

(B)

Inspect additional-220 0 tubes in steam generator A to determine suitability of new probe.

2.

Remove tubes R13C67,

R11C69, R14C70, and R32C71 from steam generator C from below the first support plate in order to:

(A)

Establish condition of tubes near and away from regions of the tube sheet being anected by apparent lGA at the 115.

(B)

Correlate existing eddy current data with actual condition of tubes.

(C) Correlate eddy current data from new probe with actual condition of tubes.

In-situ pressure tests.

(A) Perform in-situ pressure tests.

(1) Establish that tubes "Leak Before Break" to reduce safety concern.

  • (2)

Establish margins of structural integrity of tubes affected by IGA.

(3)

Determine the fracture mode of tubes affected by IGA (i.e., axial rupture or circumferential rupture).

(B)

Tubes which exoerience rupture will be visually examined by fiberscopic technique to determine fracture mode.

C Data obta-icA will be "scful, if

--ot cssential, in justifying continued operatior i tin absence of knowiledge of the rate at which lGA corrosion is occurring.

III. RESULTS FROM REVISED INSPECTION PROGRAM A.

Eddy Current Inspections with New Probe in Steam Generator A.

1.

Technique is sensitive to IGA whenever grain boundary sparation is present (IGA cannot be reliably detected and quantified otherwise).

2.

Technique detects IGA in tubes hot previously detected using conventional eddy current probe.

3. Quantity of tubes requiring plugging based on the 50% plugging limit has increased..

(A) Conventional probe -

17 out of 3,699 inspected.

(B) New probe -

939 out of 1179 ins pected.

B.

Visual and Non-Destructive Examinations of Removed Tube Specimens.

1.

R13C67 This tube had a slighty distorted large dent signal using the conventional eddy current probe.

Hand probing prior to removal using the new probe yielded a 54% indication. The tube fractured at TTS on removal. Visual examination showed nearly through wall IGA at certain locations on the fracture face.

2.

R11C66 and R32C71 These tubes each had non-distorted, large dent signals using the conventional eddy current probe. Hand probing using the new probe prior to removal yielded no indication of IGA. Both tubes.fractured at TTS during removal. Visual examination showed IGA at various locations and depths around the fracture face.

3.

R14C70 This tube had no indication of either a dent on IGA using both the conventional eddy current probe and the new probe prior to removal. The tube did not fracture upon removal. Visual and radiographic examination disclosed the presence of circumferentially oriented cracks at.TTS.

Estimated depth of penetration is 35% to 4 5 % through wall. Tube will be subjected to laboratory pressure test to burst pressure followed by metallurgical examinations.

ACTIONS CONTINUE RPC EDDY CURRENT TESTING INDIVIDUAL PRESSURE TEST 5 LEAKERS IN SG-C INDIVIDUAL PRESSURE TEST TUBES (TEST FIRST ITH RPC)

PULL TUBES (TEST FIRST WITH RPC)

RCS PRESSURE TEST OF BUNDLE SS PRESSURE TEST OF BUNDLE PLUG TUBES CHEMISTRY FLUSHING INSTITUTE CHANGES IN CHEMISTRY CONTROL REDUCED CONDITIONS OPERATIONS I

REPAIR

SAN ONOFRE #1 STEAM GENERATOR TUBE INSPECTION EDDY CURRENT DATA ANALYSIS FOR THE APRIL, 1980 OUTAGE

SAN ONOFRE #1 STEAM GENERATOR TUBE INSPECTIONS BACKGROUND DENTING Successive inspections since 1977 demon strated that no significant progression of denting was occurring.

ANTI-VIBRATION BAR WEAR Tube degradation due to wear prior to 1977 was arrested by the insertion of an additional set of square, Inconel (chromium plated) bars.

THINNING Tube degradation due to phosphate thinning in the sludge pile region at or above the tube sheet had been progressing at a low rate through October, 1978.

SAN ONOFRE #1 EDDY CURRENT DATA EVALUATION JUNE, 1979 OUTAGE

  • Leak check showed 2 tubes leaking in SG/A.
  • One in tubesheet crevice
  • One at top of the tubesheet
  • EC Program in SG/A:

639 hot leg tubes to #1 support plate @ 400 kHz.

  • 21 tubes with EC & 50%
  • 37 tubes with EC> 20%450%
  • 10 tubes with EC < 20%

.Tubes plugged - 21

  • 19 for EC indications at top of the tubesheet.
  • 2 for EC indications in the tubesheet crevice.
  • SG/C inspection program:

215 hot leg tubes to #1 support plate @400 kHz.

  • No quantified indications
  • No tubes plugged
  • 52 tubes reported with distortions of the tubesheet signals include R12C36 which leaked in April, 1980.

SAN ONOFRE #1 SG TUBE LEAKAGE: APRIL, 1980 Low level tube leikage (approx. 50 gpd) reported during February March, 1980 after outage for maintenance.

Increased tube leakage apparent in early April reached approx. 250 gpd.

Shutdown April 8 was three (3) days in advance of refueling outage schedule.

Hydro test of SG's confirmed tube leakage in SG/C (5 tubes); possible tube leakage in SG/B.

Hand probing of leakers and 2 other tubes showed deep penetration EC signals at the top of the tubesheet in SG/C.

The EC program was modified to encompass all hot leg tubes to at least the #1 support plate.

SAN ONOFRE #1 SG FLOW SLOT INSPECTION Central flow slot in all 3 SG's have been photographed in each scheduled inspection beginning in October, 1976.

Initial photos revealed flow slot hourglassing and.ligament cracks in SG's A and C; the flow slots in SG/B appeared normal.

Inspection of the upper flow slots(#3 and #4 support plates) through a 3" inspection port in SG/C indicated no distortion.

The absence of hourglassing in the upper plates of SG/C and all the plates in SG/B coincided with the absence of significant denting in those plates; by inference SG/A has no hourglassing in the #3 and #4 plates.

Measurement of average flow slot width reduction has shown no significant change thro ugh 5 inspections (10/76, 9/77, 4/78, 10/78 and 4/80)

SAN ONOFRE #1 SG TUBE GAUGING INSPECTION APRIL, 1980 OUTAGE Evaluation of denting progression is also accomplished by review of tube ID restriction data.

522 tube inspections in SG/A and 362 in SG/C were extended through the

  1. 4 support plate in addition to the U-bend scope in each to provide data on tube ID restrictions.

Only 2 tubes in each SG blocked passage of a 460 mil diameter probe.

2 cold leg tubes in SG/A were not previously tested.

2 hot leg tubes in SG/C passed 460 mil probe in prior inspections.

19 other tubes blocked passage of smaller probes than in previous inspect ions.

Overall conclusion:

No significant change in denting status has occurred.

SAN ONOFRE #1 APRIL, 1980 OUTAGE STEAM GENERATOR "A" GAUGING Sumnary of Inspection Results INLET OUTLET TUBES GAUGED 398 179 Tube Restrictions

<.AO 0

2

.400 -

.460 0

0

.460 -

.500 19 11

.500 -

.560 50 26

.560 -

.580 109 21 TnT[J RETRICTED TUBES 178 60

SAN ONOFRE #1 APRIL, 1980 OUTAGE STEAM GENERATOR "C" GAUGING Summary of Inspection Results INLET OUTLET TUBES GAUGED 461 69 Tubes Restricted

<.400 0

0

.400 -.460 2

0

.460 -

.5C0.

6 2

.500 -..560 95 17

.560-.530 82 6

TOTAL RESTRICTED TUHES 185 25

SAN ONOFRE Jil1 STEAM GENERATOR EC INSPECTION APRIL, 1980 OUTAGE Phase I EC testing was accomplished using multiple frequency eddy current equipment.

Four frequencies were multiplexed to provide simultaneous readout.

  • 400 kHz Differential - comparison to all prior inspection data.

. 340 kHz Differential - optimal frequency for inspection of 55 mil wall, 0.750" Inconel-600 tubes.

. 100 kHz Differential - 0.D. sensitivity enhancement and tubesheet response for signal mixing.

. 100 kHz Absolute - Heighten response to gradual changes.

SAN ONOFRE #1 APRIL, 1980 OUTAGE EC INSPECTION PROGRAM A

B C

INLET OUTLET INLET OUTLET INLET OUTLET TOTAL TUBES 3794 3794 3794 3794 3794 3794 PREVIOUSLY PLUGGED 95 95 50 50 124 124 REMAINING IN-SERVICE 3699 3699 3744 3744 3670 3670 ACTUAL INSPECTION Through U-Bend 475 16 754 12 592 39 Through 4th Support 343 179 346 16 Through 1st Support 2881 1803 2990 640 2732 305 TOTAL 3699 1998 3744 652 3670 360

SAN ONOFRE #1

SUMMARY

OF EC INDICATIONS 20%

CONVENTIONAL EC TESTING A

B C

INLET OUTLET INLET OUTLET INLET OUTLET LOCATION OF INDICATION At Anti-Vibration Bars 279 0

472 0

363 0

Above Tubesheet 393 249 146 95 128 35 At Top of Tubesheet 139 3

48 0

156 0

Below Tubesheet 1

0 0

0 0

0 TOTAL 812 252 666 95 647 35

DSRIBFUTIoN OF --

HE C-1ANGE IN AV13 WFAR IDICAT4ONS RECoROED AS > Zo% AT Bar aH _ wo071 ANO 5-/e jNSPE CTIoNs SAN ONoIF UNI-T. I STEANl GENERATOR 7 -

___NUMBER -OF INDICATIONS COMPARED S6

-AN INDICATION Size q.79 A L_STAN D VIATI 5.-

z q.Ill 20 17

-zo

- 7

-10

-5 O

5 10 Is 20 CHANG IN INDICATION SIZE

(% WAL..- PENE.TflATION)

ISTR I

-UTro OF T-E CHANGE IN /V. WEAff INDICATicN S RECORDED AS !

",6 AT OTH THE )0/718 AND 5-/90 IN SPecTIONS At'UO..JO

-UN IT STIEAtV GaNERATOR E

0 C\\J

-~F 7

I L NUMBER OF INDICATIONS

-I...

COMPARED

=

12 MEAN INDICATION SIZE

/,98 OA STANOARD DEVIATICI 9.2 2

S-SALSO RIE-PRTE O L

J 2

3

-20

-JG

-10 0

6-io 15" 20 CHANGE IN INDICATION GIZ$. - (%WALL F'ENE.TRATION) t..'..

5.. =I

oiSTR IBUTIoN OF THE CHANGE IN AVB WEAR INDICATIONS RECORDED A$

. ?0%

AT BOTH THE. 10/79 'AND'5/80 NSPCtIoNS SSCE.-SAN ONOFRG.UNIT#

STEAM GENERATOK C

-140 3NUMBFeRE OF INDICATIONS C QM PA-I E F-VE ND N

o 0 -

.STANDARD DEVIATION 3

-Z-10O 0

0

  • ~

9L 30 O-~

22.

K 10

.0

-ao

-is

-10

-5 o

o is o

CHANGE.. IN INDICATION I7ZE

(%WALL P.NRTkRATIoN)

I 6TR t b OT I CN

-01:

ALL Ct)

CL f f S r INDICATIONiSZ Zo/v C40c KRA).

IN T H c- -TLr!r i:irH R Err RP0 T,'T SI AT T1417. fl(A 1 LA4uN'e 1980 IN6PWI.QT ION foTT A

A..

WCT Ilb

.60 INVoTOit;IZ-

c.

-A.

TPSNTLRbC.ATOu52

.f-E 9-11 4 I I

V

EL IL S...

46 1320 I

DISTRIBUTION O F E CCY CUFtrRENT INDCATIONS I 20;%

(,YOO kH

/11SOVE THE TUE SHRET 177 REPORTED AT THE..My

- JUNE 1980NSPEC 7--O N.

syI%.,N CINONFZR UNIT 1 E I PN\\ G ER ATCR SO o

N NoCATIONS

=393 IN ADDITION:

0 I

~

4*

I91

< 3o 3a.

20.

10 -2//

IIII 20-2q 25-29 30-3q 35-39 A90- y9 q5-905-9q53 06 65-69 70-7q 76-79 80-8V S5.-83 90-9y 95--99 oNDIATION 51ilE (0/ lb4yLL PENErATION14

10-N.5

-40 N

-j F.W F

A~TTH.

OFOFTIIE1Loi T

i

.~ D TiON 13 I

.0

~~j.

A A1-K i20

46 1320 DIST R Is:.LTICM i AL%_

Cb.LR R t Mr INDCAT IONS 20 /

40

<HZ AT -TH VET-T RE-POVr:TED ATr "itrk)

MAY-JUaid5 9R80 INSPECTION:

I:~1 i;

IT~

TOTAL CATI 07 9

20-41 z

lo' 20-2 Z5 29 30-3q 35-39 'YO-WY '!-0

-CV 5 -

9 6o-656-6c. 70-7q '7,:'-7) 90-81 85-33) 90-91.95-.99 i N D I/ 1-oN f1-r.( VA//L L PENETRATION)

46 1320 l

N T

D.

ovE MER TL C-H CT T

11

(~**

CNCioN rU43 O

2.I 6 it 1

lICA ONs 143 30 ILI 2.I III ZO02 Z S'-S2 30- > 3 5-33 (0,7'-Y o-v -

-6Y CS66 70-7Y 737980899-89 9o-9Ya 95o0 IDrA-r c/

\\NALL PENETRATION

46 1320 DITIB31ATick OF anY 2jcu ENt IND AT)

Tr~

V o-roP OF rt TAaFT 0

n RE~ MT T-1 Wr StsS E

V99 ATo C

C t v iLI\\

IAil LINI I

I 30 20 ZO-Z Z5-29 30-3/ 3S-39Y O-VS V V T-3 6.0-69665-60 70-7Y 7-79 8O-BY 85-89 90-9y 95-99 INDICATION SIZF

(-,

V'JALL PENLi-riATION )

KL<

t

T l

.46 1320 p

ISTI~uON i" l-.

EDY URRNTNDICATIONS -'20 %"c AT THETU'2E.T

.0N FEFO[TE AT -r. M1 JUNE 1980 Iri MPECTION S TEAM GaM E kA'TO R C

OTAL 0ICAr ON.

S 2

30.~E

~.~

27 198 (0-63 5

7H z

-o INo rloN SI h

(Ii)

TALL Pi7NETrRAT8ON'

1,1 X 10 TO INCH 7

c ES 46 1320 LIFFEL & ESSER CO

-0e LIS.

DTRBUTION OF EPD*Y CURRENT INDiCPTIcNS

> 2 A8V THE TUSFISHEET H E_

M A 1 9 3 IN P

C ~

RSPORTED AT TH M

U3 N

.UNSAN ONOF t UNIT 1 S EAM GENERATOR C

0)I 2

-I I

70AL I r o -

20-2Y 25-29 30-3~ 35-39 £9-?I 9d5-'V-9 50-5't SMS-Go-ey 65-E3 70-79 7 r79 80-Bl 86-89 90 $9 95-99 INDICATION SIZE(a WALL PENETR nATON).._._

L I

~~~~'

T...

S477 4 6 1.320 D IsT R i bU T IN OF EL)CY CUFKR'.-rr INDI1CATIONS

_O ko7z ('0'J4 AT-THE I -rctz OF THE~

E E.H,,-rT

+ RE.PORTEC AT Tki41 iVAj AWNr-t vq8oA NS PeCTION ',

fT, LNNI GENERATOR'C 150 7

S.

A-a 3_

Io2 Z-303 ac -Zo

&c -v li-q T

__-6

___-7 4C--

SO64 as9

-y W-90 lNVI\\.N SIE C.VL-E ITI O

SAN O~fFRE # 1 APRIL, 1.980 OUTAGE CONWNTIONAL EC DATA ITEPPRETATInNS AVB SIGNALS SHOW NO SIGNIFICANT CHANGE NO SIGNIFICANT CHANGE IN TUBE DENTING SLIGHT INCREASE IN APPARENT THINNING BETWEEN TUBESHEET AND FIRST TSP ONLY ONE TUBESHEET CREVICE INDICATION (TUBE SAMPLE REMOVED FOR EXAMINATION)

SIGNALS AT TOP OF TUBESHEET ARE COMPLEX THREE CATEGORIES

1.

TUBESHEET ENTRY SIGNAL ONLY 2,

DENTING + TUBESHEET ENTRY

3.

PENTING + TUBESHEET ENTRY-CORROSION SEVALUATIONS OF CnPLEX SIGNALS ARE IN PROGRESS

SAN ONOFRE #1 SG TUBE REMOVAL DATA STEAM GENERATOR A Laboratory evaluation of three tubes was deemed necessary to determine the nature of tube.degradation exhibited by the EC data and the tube leakage events.

  • R24C71 HL -

Section from #1 TSP down.

In-plant EC data:

95% at tubesheet.

26% 12" above tubesheet.

Tube fractured at 95% indication on pulling.

  • R31C28 HL -

Section from #4 TSP down.

In-plant EC data:

Complex signal at tubesheet.

Tube fractured at complex signal on pulling.

  • R17C52 HL -

Section from 2" below top of tubesheet down.

In-plant EC data:

95% 4" below top of tubesheet.

Tube cutter lodged at #3 TSP; surrounding tubes to be plugged.

SAN ONOFRE #1 EXPANDED SCOPE SG INSPECTIONS Apparent tube.degradation on tube with complex signal indicated need for more specialized NDE techniques and additional tube pulls.

Additional EC testing with probes optimized for locating circumferentially oriented degradation.

  • Multiple, series-wired pancake coils on a straight pull probe did not produce significant improvement over original equipment.

" Backup - *a single, rotating pancake coil probe did provide increased sensitivity and circumferential extent of apparent decradation.

Inspection program based on non-routine 100 kHz signal patterns from.con ventional EC data plus one apparently normal tube around the "red dots" calls for 2270 tubes to be tested with the Rotating Pancake Coil (RPC) probe in Steam Generator A.

OO__GOOOn99 O3:

0---

109 o

f-r1 a a o

-p--

937 9o 9

71 o

0 0 I --- l o

-ogo 93 gr 80 00 91 oT oor 89

- r N7

__rna_

TaLI un'o 86 85 z

rr

-h r- -

1.

o_.-__-__-----

,~~~1 r

oI oL 1

80

~8 3 o

ou -

7 9 O

n 77 h

DQLd.

a 76 o

a--

7 5 ok uo D 7 4

.4oL0-.-

73 OKI 72 7 0* * ' a -

+--*4V-7 OO 70 or a

no69 C)

O n n.-

n 1S O

I-6'8 OH-6 7

o-a*

t a

65 o-7 63 S-62

~

r-~4Q ----r4 71 o

a 57 56 Do 55 f~47 o

r

.,2 2 3 0

~

. '3:'t-J 4

28 77 48 o

--14 1 04 0 0

3 7 r

/C 11

-41 344 IT 32 o~~~~

1

_2 --

C24 23 El y 2

0 22 oT

<ooo1 o

-}

oo1 1

o --

C O oo 000

-e s

O~

2ua

) U0 11o (O

4-0 J(

11 0-0U db1

-TT al

HELICAL SCAN EDDY CURRENT PROBE Centering Fingers 3-/

Rotating Probe Body Eddy Current Coi l Centering Fingers

SAN ONOFRE #1 APRIL, 1980 OUTAGE SECOND PHASE TUBE PULLS STEAM GENERATOR C Four additional tubes identified for removal to characterize the tube condition corresponding to the EC data in the original data base.

All were hand-probed with the RPC prior to removal.

1. R13C67 HL Apparent large dent signal with slight distortion; 45% and 55% RPC indications.
2. RlC69 HL Apparent large dent signal; No RPC indication.
3. R32C71 HL Apparent large dent signal; No RPC indication.
4. R14C70 HL Apparently normal tubesheet entry signal; No RPC indication.

Tubes (1), (2), and (3) fractured upon pulling at the position ccrrespondinc to the dent-like signals; IGA evident at the fracture faces of each tube.

Tube (4) removed intact but slightly stretched; exhibits visible circum ferentially-oriented cracks measured between 40% and 50. by O.D. surface probe.

SAN ONOFRE #1 STEAM GENERATOR A INLET ROTATING PANCAKE COIL INSPECTION RtESULTS JULY, 1980 Tubes evaluated (0800, 7/9/80) 1179 Results No detectable Indications 772

< 20% Indications 76

>20%<50% Indications 61

> 50% Indications 270 Number of New Indications 248 Number of New, 50% Indications 122

SAN ONOFRE II APRIL, 1980 OUTAGE

-.ERIES 27 S

CE-A wome~eme e se ocattoitato tert mmem NNN -----

'-D-CO UMN 47 35 OsOo e

00000000000000 446 45 000.::0000 4

113 M wa C

9o O

4 1 Tuo0Cnv tf.n on 35 Tu O

.P Oill 1

35 As..

00 ---

32 1 so.

a 31 no~~

29 I

-H3

/

H n

1w o---

23 a-a0 2 1-2

/-------

o-20 a

N --

96

/-

21 a1 0

20 06 1

4

+~

--- 23

.00 000 000 000.00 000 000 000.80 coo oo ooo oc ooo ooo ooc oon o m e o m e acc~ co ooc ooo ooo soAO W

MA9A sTbspugdpro o18 O Z E MAN AY asr Tubes -p.uge po 60 t/otin P1 ncak CoZZl

I OF

.I

.OLANtD to0 c--N pr 1-7 1918o

~I0 2.II 100 130 o 12.0 ~

I12.1

-o

-10 a

41 O

z0.

o I

t D

< 2 P 1o

.1 N o -Z M 4 0 41 C.

( -

9 1 0- 7 o -eA L L I -- ?I Iir-t rAnTa~ 177.(ft VldLL PGI~ jTCZT

SAN ONOFRE #1 JULY,.1980 SELECTION OF TUBE PULL CANDIDATES OBJECTIVES

1. Maximize identification capability of pluggable tubes.

Bobbin (conventional) probe EC data.

100 kHz Mixed signals

  • Rotating Pancake Coil EC data comparison

- Pull tubes EXPECTED EXPECTED SG CANDIDATE BOBBIN RPC METALLOGRAPHY CONCLUSI0N 400 kHz 100 KHz MF A 24-43 Normal Dent Yes Dist..Dent Dent + NDD

< 60%

OK A 20-58 Entry NDD NDD NDD

( 60%

OK

2.

Verify RPC Data Calibration Pull Tubes EXPECTED EXPECTED SG CANDIDATE BOBBIN RPC METALLOGRAPHY CONCLUSION 400 kHz 100 kHz MF A 12-70 Small Dent, Yes Small Dent,200 4-20%

OK A 15-70 Small Dist.

Yes Small Dist. 35%

L-35%

OK Dent Dent A 17-61 Small Dent Yes Dist.Dent 62%

L 62%

OK Vit

SCE UNIT NO. 1 PRESSURE TESTS OBJECTIVE:

CONFIRM LEAK-BEFORE-BREAK AND SUBSTANTIATE BUNDLE STRUCTURAL INTEGRITY EXAMINED PROFILES ARE NOT UNIFORM WE HAVE LEAKERS A SMALL UNIFORM THICKNESS (5 MILS) WILL CAPRY SUBSTANTIAL PRESSURE (2000 PSI)

SCE UNIT NO. 1 MINIMUM TUBE WALL REQUIREMENTS

  • DEGRADATION MODE -

UNIFORM THINNING (IGA)

  • DEGRADATION LENGTH =.5 INCH
  • SAFETY REQUIREMENT -

NO TUBE RUPTURE MIN. REQ'D. WALL PLANT CONDITION Ap, psi MILS

% OF NOMINAL

  • 100% STEADY-STATE 1350 3.5 6.4%
  • LOSS-OF-LOAD ACCIDENT 1715 4.4 8.0%
  • FLB ACCIDENT 2560 6.3 11.5%

PRESSURE TESS FOR LEAK-BEFORE-BREAK VERIFlATION SINGLE TUBES -

LEAK RATE AND MARGIN TO BURST PN BURST -

FLB (-'2000 PSI)

PRIMARY HlYDR0 -

ESTABLISH MINIMUM BUNDLE CAPABILITY, P MIN PMIN =

HYDRO +M PHYDRO, 2000 PSI SECONDARY HYDRO -VALIDATE LEAK-BEFORE-BREAK BY PLUGGING ALL LEAKERS.

CONTINUED OPERATION CORROSION ARREST

sTI1[",'r PQ[. s'Yft r i Tr:TS.

OBJECTIVE:

SPECIFICATION OF ACCEPTABLE LEAK RATE, W DERIVATION OF MARGIN TO BURST, PM TUBE SELECTION BASIS:

ACTIVE REGION LEAKERS CONVENTIONAL ECT TEST CANDIDATEC.

LEAKERS (5) INSG-C R11C45, R12C36-38-48-51 NON-LEAKERS (9) IN SG-A R-C RPC CONV. ECT 13-36 85% - 1800 60%

13-40 94% -

2100 99!

13-41 89% -

1800 96%

13-42 86% -

2400 80^

10-45 74 2100 392 11-41 DENT 14-39 12-55 14-40

PRELIMLN* RESULTS FROM SCE UNIT #1 LEAKING TUBE PRESSURE TESTS FOUR TUBES TESTED TO MAXIMUM PRESSURE OF 5500 TO 6000 PSI WITH APPARENT CRACK OPENING BASED ON FIBRE SCOPE OBSER VATIONS MAXIMUM FLOW RATE UNDER MAXIMUM PRESSURE WAS< 1 GPM FLOW RATES UNDER NORMAL PRESSURE WERE APPROXIMATELY 0.02 0.03 GPM

Retrieved from "https://kanterella.com/w/index.php?title=ML13319A718&oldid=5224145"