ML20149M177

Summary of 880115 Meeting W/Util Discussing Generic Implications of Cracked 6-inch Safety Injection Pipe at Plant.Meeting Attendees & Agenda Encl

ML20149M177
Person / Time
Site:	Farley
Issue date:	02/08/1988
From:	Reeves E Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
TAC-66773, NUDOCS 8802250389
Download: ML20149M177 (105)

Text

!

. l h o UNITED STATES

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, .E NUCLEAR REGULATORY COMMISSION WASHINGTON D, C. 20555 t

k, *....p FEB 081988 Docket Nos. 50-348 and 50-364 f.!CENSEE: Alabama Power Company (APCo)

, FACILITY: Joseph M. Farley Nuclear Plant, Units 1 and 2 ,

SUMMARY

OF MEETING HELD ON JANUARY 15, 1988, BETWEEN NRC AND APCo REPRESENTATIVES TO DISCU5S GENERIC IMPLICATIONS OF A l CRACKED 6-INCH SAFETY INJECTION PIPE AT FARLEY UNIT 2 (TAC 66773)

Introduction The NRC Project Manager (E. Reeves) reviewed the purpose of the meeting as noticed. The meeting was requested by NRC to have APCo discuss the event,  ;

the actions taken following the event, the results of the metallurgical examinations, the causal factors (thermal fatigue), the actions taken to preclude further problems, and a review of the small break loss of coolant t accident reanalysis. The list of attendees and a meeting agenda are f enclosed. Enclosure pages 1-98 are the handouts used during the meeting. F Discussion I

] APCo (R. P. Mcdonald, Senior Vice President Nuclear) provided the opening l remarks and noted that J. Garlington of APCo would coordinate the presentations which included Westinghouse representatives (G. Rao, D. Rourty and R. Magee) and APCo (R. Fucich and S. Burns). The handouts were used  ;

extensively during the discussions of each specific area identified in the ,

enclosed agenda. A vief synopsis is given in these minutes. E i

i The event occurred at Unit 2 on December 8, 1987, as described in Licensee l

Event Report No.87-010 dated January 6, 1988. A coolant pressure boundary leakage of sli

injection (SI)ghtly lessonthen piping the 1.0 gpmcoolant reactor was discovered in aBsection system loop of safety cold leg. The l

I unit was operating at 33 percent power prior to shutdown on December 9. The  ;

i refueling outage for Cycle 6 operation had been completed on December 2,1987. l' l

, APCo (R. Fucich) presented a discussion, II. Overview (enclosure pages 1-7),

including the crack sumary, event chronology, testing methodology and l j instrumentation installed on loop B and C SI line sections. He stated that j the interim engineering evaluation attributes the crack to thermal fatigue and a supports continued operation of both units while the evaluation is being finalized, i

4 APCo (S. Burns) presented a discussion, !!I. Inspections (enclosura pages {

j 8-16), including test personnel, procedures, and non-destructive examination (NDE) techniques. The results using enhanced ultrasonic techniques confirmed i j

the presence of cracks on both sides of weld #16 with approximately 6-inches I of combined length. The through-wall crack was about one inch in length at i the 6 o' clock position (bottom of a horizontal line). Table 1 on enclosure  !

page 16 shows the NDE test results of the 6-inch loop B S1 line welds

] including weld #16 which cracked. 8802250389 880208 ADOCK 050 0 gDR

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Westinghouse (G. RAO) presented a discussion, IV.1 Metallurgical Evaluations ,

(enclosure pages 17-47), with the objective of establishing the mechanism and ,

causes of the cracking. A sumary of the results of surface examination  ;

) confinted the presence of circumferential cracks, one on each side of the weld, approximately three inches long which then ran into the weld metal near l the 6 o' clock location (refer to pages 22 and 23 of enclosure). Fractographic examination results suggest that cracking was initiated on the ID surface and i g progressed radially outward to the OD. The conclusion is that the cracking l 1

occurred by a high cycle fatigue mechanism. No abnormalities were reported in the mechanical or chemical properties of the pipe or the weld.

Westinghouse (D. Rourty) presented a discussion, IV.2 Evaluations of Unit 2  !

Loop Experience (enclosure pages 48-53), describing the operational test

! program installed on loop B and on loop C as a control location. Both thermal measuring instruments and vibration instruments were utilized in the

! analysis. The thermal measurements revealed that large temperature

, stratifications (exceeding 200*F) and temperature fluctuations existed from the

! top to the bottom of the SI pipe in the bottom of the pipe where the failures (cracks) occurred. The evaluation shows that cooler water in small quantities '

(less than 1 gpm estimated) was flowing through the upstream checkvalve in the  ;

B loop SI piping. The colder water came from a leaking bypass valve around the ,

i boron injection tank. When the flow was diverted to reduce the pressure up- ,

stream of the check valve, the temperature cycling and stratification ceased, f Westinghouse (D. Rourty) continued with a discussion, IV.3 Analytical  !'

Evaluations and IV.4 Conclusions (enclosure pages 54-58), which concluded that the pipe cracked by fatigue due to thenr.al loads resulting from thermal  !

cycling combined with temperature stratification. i l

The discussion continued with agenda item V, Forward Looking Evaluations and Actions, with the participation of Westinghouse and APCo representatives. -

i This included discussions of fluid systems, impact of in-leakage on the nozzle  !

i thermal sleeve, and other lines subject to similar experiences. Other lines were the auxiliary spray line, normal charging and alternate charging lines, and  :

) both the cold leg and hot leg SI lines. Westinghouse (R. Magee and D. Rourty) f gave these discussions. The conclusion was that a potential mechanism exists on :

the hot leg SI line as well as the cold leg SI line, but the probability is mi- l nimized given a secure pressure boundary from cooler water in-leakage as i occurred in the B loop cold leg SI line where the crack was found. The auxilary L spray line and the normal and alternate changing lines would not be of signifi- l cant concern according to the evaluation presented (enclosure pages 59-71). t 1 Thermal sleeves located inside the SI lines at the entry to the reactor coolant .

loop were considered in the evaluation. Farley Unit 1 and 2 B loop cold leg SI line thermal sleeves were previously dislodged and recovered in the reactor [

vessels (Unit 1 during the 1983 refueling outage and Unit 2 during the recent outage). Westinghouse has recomended elimination of thermal sleeves from such plant designs later then the Farley time frame. Previous Westinghouse i

studies have concluded that the thermal sleeve failures resulted from flow  !

induced vibration. The discussion V.2 Thermal Sleeve Considerations [

(enclosure pages 72 and 73), concludes that the thermal sleeve integrity and [

! nozzle integrity would not be affected by the thermal mechanism which caused

the pipe cracks.

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. Westinghouse (D. Rourty) concluded the discussion with agenda item V.3, ,

Continued Acceptability of Units 1 and 2 (enclosure pages 74-93). The review  !

was very comprehensive including the list of items shown on page 74 of the enclosure. The thermal cycling mechanism which resulted in the crack ,

projection was clearly shown by use of temperature profiles versus time plotting. A conclusion was drawn that the preliminary leak-before break i evaluations indicate that no double ended break would occur prior to leak ,

i detection.

Sumary l

The licensea (R. Mcdonald) sumarized future actions being considered at this  !

time as follows

l l (1 Additional monitoring review (2 Completion of the final Westinghouse analyses l (3 Contact with Owner's Group in active lead role '

(4 A revised entry to the INP0 Notepad to supplement their earlier one i

, (5) Westinghouse considering letter to customers APCo (J. Garlington) presented agenda item VI, A Small Break Loss of Coolant  !

Accident (SBLOCA) Eveluation (enclosure pages 94-98). He noted that a letter  :

dated January 14, 1988, has been sent to NRC with the detailed description per  !

! 10 CFR 50.46, Appendix K. Evaluation results (see page 97 of enclosure) show i t a +46*F spillage correction and a + 9'F reporting correction. Thus, Units 1  :

j and 2 proposed fuel peak clad temperatures are 1875'F and 1758' F, respectively.  !

j Considerable margin exists to the 10 CFR 50.46 limit of 2200'F.

l In closing, APCo (R. Mcdonald) expressed appreciation for the opportunity to l review the current status of the actions taken since the event occurred. NRC (G.Lainas) expressed the staff's appreciation to APCo for a very complete and i detailed licensee presentation. At this point the meeting adjourned.

Edward A. Reeves, Senior Project Manager Project Directorate 11-1 Division of Reactor Projects - I/II

Enclosures:

As Stated cc w/

Enclosure:

See next page P4 1 D -1 ERe es EA nsam 2/ /88 2/ /88

. MEETING SUPMARY DISTRIBUTION n

f 36V J. Docket No.: 50-NRC PDR

/

Local PDR PD 11-1 r/f E. Adensam Attorney, OGC P. Anderson E. Jordan J. Partlow ACRS (10)

Project Manager E. Reeves NRC PARTICIPANTS E. Reeves E. Lobel R. Woodruff G. Lainas E. Merschoff A. Herdt C. Y. Cheng K. Wichman W. Troskoski H. Dance I. Bukulmez J. Thoma M. Hum S. Seller S. Lee R. Jones W. Hodges J. Richardson P. Kuo Mark Hartzman Kamal Manoly E. Brown W. Hazelton  ;

L. Marsh R. Wright K. Eccleston I

CC: Applicant & Service List l

1

f e

Mr. R. P. Mcdonald Alabama Power Company Joseph M. Farley Nuclear Plant 1

cc:- . -

Mr. W. 0.-Whitt D. Biard MacGuineas. Esquire Executive Vice President Volpe, Boskey and Lyons Alabama Power Company 918 16th Street, N.W.

, Post Office Box 2641 Washington, DC 20006 .

Birmingham, Alabama 35291-0400 -

Charles R. Lowman Mr. Louis B. Long, General Manager Alabama Electric Corporation Southern Company Services, Inc. Post Office Box 550 Post Office Box 2625 Andalusia, Alabama 36420 Birmingham, Alabama 35202 Chairman Regional Administrator, Region II Heuston County Comission U.S. Nuclear Regulatory Comission Dothan, Alabama 36301 101 Marietta Street, Suite 2900 Ernest L. Blake, Jr., Esquire Shaw, Pittman, Potts and Trowbridge Claude Earl Fox, M.D.

2300 N Street, N.W. State Health Officer Washington, DC 20037 State Department of Public Health State Office Building Robert A. Buettner, Esquire Ealch, Bingham, Baker, Hawthorne, Mr. J. D. Woodard Williams and Ward General Manager - Nuclear Plant i Post Office Box 306 Post Office Box 470 Birmingham, Altbama 35201 Ashford, Alabama 36312 1 i

Resident inspector I

U.S. Nuclear Regulatory Comission l Post Office Box 24 - Route 2 i l Columbia Alabama 36319 1 l

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Enclosure List of Attendees 4 E. A. Reeves, NRR R. Lobel, NRR Roger Woodruff, NRR  :

G. Lainas, NRR  !

E. W. Merschoff, RII A. R. Herdt, RI! t C. Y. Cheng, NRR I K. R. Wichman, NRR  ;

. W. Troskoski, OEDO

H. C. Dance, RI!

I. Bukulmez, NRR- ,

J. Thoma, NRR  ;

M. Hum, NRR  :

C. D. Sellers, NRR l

S. Lee, NRR  ;

R. C. Jones, NRR j Wayne Hodges, NRR ,

D. V. Jagannath, Bechtel K. C. Gandhi, Bechtel .

. W. J. Engel, Bechtel  :

A. A. Jerome, Westinghouse Ken Voytell, Westinghouse j 4

Robert Magee, Westinghouse .

David Rourty, Westinghouse  ;

Gutti Rao, Westinghouse J

.i-C'em Eicheldinger, Westinghouse  ;

.id Burcs, Alebama Power Co. '

Robert Fucich, Alabama Power Co.

Robert Davis, Southern Co. Service 1

D. C. Adamonis, Westinghouse Bill Shipman, Alabama Power Co.

John Garlington, Alabama Power Co. l

i Pat Mcdonald, Alabama Power Co. '

l Jim Richardson, NRR P. T. Kuo, NRR i Mark Hartzman, NRR ,

Kamal Manoly, NRR 1 Walt Tauche, Westinghouse '

i* Robert Osterrietder, Westinghouse Carl Hirst, Westinghouse j Earl J. Brown, AE00  :

1-Warren S. Hazelton, NRR  !

L. B. Marsh, NRR  !

Robert J. Wright, NRR  ;

K. Eccleston, NRR l

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. MEETillG AGENDA j

JANUARY 15, 1988  :

! Farley Nuclear Plant Unit 2 Cold Leg i

Safety Injection Line Crack l j 9

00 a.m. 1. Preface - Opening Remarks -R. P. Mcdonald [

9

10 a.m.  !!. Overview R. S. Fucich f 9:35 a.m. III. Inspections - Nondestructive examinations S. T. Burns i 4 at FNP >

1 ,

i

! IV. Evaluations With Respect to Unit 2 B Loop Westinghouse  !

! Experience  ;

)

j 9:45 a.m. 1. Metallurgical evaluations -- Sa77/ #AO - kM [

10:30 a.m. 2. Test instrunentation .9AP/4 80uMr -- JAJ ,

i 10:45 a.m. 3. Analytical evaluations - DA VC /?d#N .!dd 11:20 a.m. 4. Conclusion l

! V. Forward Looking Evaluations and Actions v i (Units 1 & 2) f

i

! 11:30 a.c. 1. Discussion of other locations in Westinghouse -f Units 1 and 2 subject to same concern /dBMT NM&

11:40 a.m. 2. Thermal sleeve evaluations sgghgse 11:50 a.m. 3. Contint.ed acceptability of Unit 2 B loop Westinghouse  ;

CL SI line and components /),fvud7V 12

00 p.m. 4. Summary of future actions R. P. Mcdonald  !

! i

) 12:10 p.m. VI. Small Break LOCA Analysis J. E. Carlington i i  !

12:20 p.m. VII. Questions and Answers All VI!!. Conclusion R. P. Mcdonald l l

1 i

[, $(/skfl$dC!~ h? A/OCN CRACK

SUMMARY

4 EVALUATIONS AND TESTING CONDUCTED TO DATE-INDICATE THAT THE CR7* KING RESULTED FROM FATIGUE CAUSED BY THERMAL CYCLING J

OVERVIEW PURPOSE I

TO QUICKLY REVIEW THE EVENT AND ACTIONS TAKEN TO DETERMINE ITS CAUSE TO SET THE STAGE FOR OTHER PRESENTATIONS WHICH WILL PROVIDE DETAILS OF INSPECTIONS AND EVALUATIONS WHICH HAVE BEEN PERFORMED TO DATE I

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, i CRACK EVENT CHRONOLOGY 's 12/08/87 (2255) UNIT 2 AT 33% POWER RETURNING FROM REFUELING OUTAGE ,

CONTAINMENT COOLER DRAIN POT LEVELS NOTED AS '

ABNORMALLY HIGH i-A CONTAINMENT ENTRY WAS MADE WHICH IDENTIFIED i A LEAK IN THE VICINITY OF THE B LOOP RESISTANCE TEMPERATURE DETECTOR (RTD) MANIFOLD  ;

A UNIT SHUTDOWN WAS MADE TO REPAIR THE LEAK >

l CLOSE EXAMINATION ATTER SHUTDOWN REVEALED PRESSURE BOUNDARY LEAKAGE IN A WELDED JOINT (WELD 16) ON THE B LOOP COLD LEG  :

SI/RHR SIX INCH LINE BETWEEN A CHECK VALVE AND THE RCS LOOP 1 I

WHILE IN HOT STANDBY LEAKAGE WAS SLIGHTLY LESS THAN ONE i GALLON PER MINUTE  ;

1 12/09/87 (1916) UNIT 2 ENTERED COLD SHUTDOWN f I

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CONVENTIONAL ULTRASONIC EXAMINATION (UT) LOCATED THE CRACK BUT DID NOT INDICATE A REPORTABLE INDICATION ENHANCED UT WAS USED TO LOCATE AND VERIFY Ti1E EXTENT OF THE CRACKr X-RAY (RT) CONFIRMED CRACK AS UNIT 1 WAS IN A SHUTDOWN (EQ MODIFICATIONS), THE FOLLOWING INVESTIGATIONS WERE CARRIED OUT ON BOTH FNP UNITS TO DETERMINE THE EXTENT OF THE PROBLEM AND POSSIBLE CAUSES:

WELDS ON EACH SIX INCH COLD LEG SI/RHR LINES WERE INSPECTED USING ENRANCED UT FABRICATION AND CONSTRUCTION X-RAYS FOR THESE WELDS WERE REVIEWED FOR ANY POSSIBLE MISSED INDICATIONS ALL SIX LINES WERE WALKED DOWN FOR EVIDENCE OF VIBRATION OR BINDING AND GENERAL PIPING GEOMETRY THE FATIGUE ANALYSES WERE REVIEWED NO OTHER CRACKS WERE FOUND NOR WERE ANY i CONDITIONS FOUND WHICH COULD EXPLAIN THE CRACX

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l THE FOLLOWIliG ADDITIONAL ITEMS WERE REVIEWED ~FOR THE UNIT 2 B LINE: _

W STRESS REPORT HOT FUNCTIONAL TEST DATA OPERATION HISTORY (SAFETY INJECTIONS, CHEMISTRY .

EXCURSIONS, WATER HAMMER, ETC.) '

NO EVIDENCE WAS FOUND TO EXPLAIN THE CRACKED JOINT THE PIPE SECTION HAS REMOVED AND SENT TO WESTINGHOUSE FOR EXAMINATION PRELIMINARY RESULTS INDICATED A' FATIGUE MECHANISM NO SIGNIFICANT MOVEMENT WAS NOTED WHEN THE PIPE WAS CUT WHILE THE PIPE SECTION WAS REMOVED, A VISUAL EXAMINATION WAS CONDUCTED ON THE NOZZLE INSIDE DIAMETF.R FOR DEGRADATION CAUSED BY THF- LOSS OF THE THERMAL SLEEVE -

REPLACEMENT PIPING WAS WELDED IN PLACE, EXAMINED AND TESTED AS REQUIRED BY THE ASME CODE RESISTANCE TEMPERATURE DETECTORS AND ACC2LEROMETERS WERE ATTACHED TO THE REPAIRED LOOP B, PIPING AND TO LOOP C AS A CONTROL

THE REPAIRED LINE WAS MONITORED DURING ITS HEATUP TO VERIFY

-THERMAL MOVEMENT WAS AS PREDICTED AND THAT IT WAS NOT BINDING TEMPERATURE DATA REVEALED A THERMAL CYCLE OCCURRING IN THE B LOOP, DOWNSTREAM OF V051B FLOW FROM THE BORON INJECTION TANK BYPASS LINE WAS DIVERTED TO THE BORON INJECTION SURGE TANK THERMAL CYCLING ON THE B LOOP, DOWNSTREAM OF V051B, STOPPED; HOWFVER, A THERMAL CYCLE APPEARED UPSTREAM V1BRATION DATA COLLECTION WAS TERMINATED WHEN VIBRATION WAS ELIMINATED AS A POTENTIAL CAUSE THE UPSTREAM THERMAL CYCLING STOPPED IN THE EARLY MORNING HOURS OF 01/08/88 BEFORE A CAUSE COULD BE DETERMINED -

AN INTERIM ENGINEERING EVALUATICN WAS OBTAINED WHICH ATTRIBUTES THE CRACK TO THERMAL FATIGUE AND WHICH SUPPORTS CONTINUED OPERATION OF BOTH UNITS WHILE THE EVALUATION IS BEING FINALIZED TEMPERATURE MONITORING IS CONTINUING

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l III. INSPECTIONS -

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1. Personnel and Procedures

• Personnel Certifications

• Procedures

2. NDE Methods, Techniques and Results

• Liquid Penetrant Examination

• Ultrasonic Examination

- Preservice and Inservice History

- Conventional Technique

- Enhanced Technique

- Summary of Results i

• Radiographic Examination

• Visual Examination

• Construction Radiograph Review  ;

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., 1. PERSCNEL AND PROCEDURES

• Personnel certified to Level II or III for major NDE (methods in accordance with Section XI and ASNr-TC-1A (1980)

' UT personnel certified to EPRI Program for IGSCC detection, sizing and overlay inspection in BWR plants

• UT procedures used:

- Most conservative application of Section XI, Appendix III (S83) requirements

- Replicated conventional procedures utilized for ISI to Section XI and Section V (S75)

' other procedures used:

- Standard practice per Section V and XI requirements ,

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l 2. NDE ME'IHODS, TECHNIQUES AND RESULTS 1 .

' Liquid Penetrant Examination

- Attempted for information purposes only

- Solvent based technique inappropriate for this application

- No meaningful results obtained

• Ultrasonic Examination l

- Preservice and Inservice Inspection history of cracked weld

• Preservice Inspection (8-20-79)  :

- O' and 45' shear wave examinations i

- visual examination L

- no indications reco ded l

• Inservice Inspection (4-17-86)

- 45' shear wave examination 1

- no indications recorded  ;

- Conventional ultrasonic examination l

' 45' shear wave transducer - 3/8", 2.25 MHz l

• upstream, downstream and two directional circumferential scans  :

• no recordable indications in excess of reference  :

levels

• scanning factors (rigure 1)

- pipe configuration limits elbow side exam due to j intrados  !

- weld crown configuration

- signal masking due to counter bore and root geometries

- beam redirection decreases angle below ideal 45' Page 2 of 4

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, - Enchanced ultrasonic examination

• 45* shear wave transducer - 3/8", 2.25 MHz

' same scanning directions

• 60' shear wave transducer - 3/8", 1.5 MHz i

• upstream and downstream scans  !

' circumferential scan at higher angles will not permit examination of ID region

• detected crack-like indications (rigure 2)

' enhancements:

- beam redirection effects on 60' shear wave improve their detection ability as true angle approaches 45'

- additional 8 db gain improves scanning sensitivity of 45' transducer

-recordinglevelat50%DACoff[$N[ l sensitivity 1

- Sumary of results

• Unit 2 (Table 1 and Figure 3)

- one recordable indication on Loop B, weld No. 16

- no other recordable indications on Loops A or C

• Unit 1

- Loops A, B and C had no recordable indications except for 3 welds which exhibited OD geometry (verified by signal danpening)

• Radiographic Examination

- Ir 192 source at 54 curies

- Double loaded cassettes using Type M film or equivalent

- Confirmed presence of crack with line filled

' crack located on elbow side

• approximately 2 1/2" long Page 3 of 4 I

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- Confirmed presence of cracks with line empty

.

• cracks located on both sides of weld

• approximately 6" long (total combined length)

• Visual Examination (Information Only)

- Utilized high resolution video camera

- VI-l visual examination-

- Confirmed satisfactory condition of thermal sleeve nozzle ID, especially areas where the sleeve was tack welded to the nozzle

• Construction Radiograph Review

Purpose:

To evaluate construction film and disposition of indications as shown on original reader sheets against the Section III code requirements

- In most cases, reader sheet accurately reflected film interpretation

'Ihere was insufficient infortcation to fully disposition 5 indications (4 on Unit 2 and 1 on Unit 1) found in the review

- Corrective actions:

• Unit 2, Loop B - None required as both welds were removed as a part of the repair (Table 1 and Figure 3)

• Unit 2, Loop A - Both welds were radiographed and results were satisfactory

• Unit 1, Loop C - One weld will be radiographed at the next refueling outage l

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TABLE 1 FARLEY NUCLEAR PLANT - LEIT 2 NDE RESULTS FROM INSPECTION l OF 6" IDOP B SI LINE & RECORDS REVIN i l SKE'ICH NO. WELD 10. UT RESULTS RT REVIEW RT RESULTS APR l-c110 18 NRI RI (3) -

(5) 17 NRI NC NRI (6) 16 RI (1) RI (4) RI (5) (7) 15 NRI NC -

14 NRI - -

13 NRI - -

12 NRI (2) - -

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NRI = NO RECORDABLE INDICATIONS RI - RECORDABLE INDICATIONS NC = NO CHANGE FROM DISPOSITION ON ORIGINAL RT READER SHEET NMES:

1. Crack-like indications determined to be approximately 6" long and 100% through-wall for a distance of 1" and centered at the 6 o' clock position.

2. Partial examination due to support clamp.

3. Slag indication 3/16" long evaluated to be acceptable.

4. Porosity with linear indications located outside the area of interest.

5. 'Ihese welds were removed and replaced as a part of the repair.

6. Weld No. 17 was radiographed to confirm the absence of defects as a result of a non-recordable indication found by Ur.

7. Informational radiographs verified the presence of cracks on both sides of the weld.

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Jf. /. METALLURGICAL EVALUATIONS -- 6. 246  :

OBJECTIVES:

0 ESTABLISH THE ECHANISM AND CAUSE(S) 0F THE OCCURRENCE .

OF CRACKING 0 DEVELOP INFORMAT10N -THAT WOL" 0 BE HELPFUL IN TAKING CORRECTIVE ACTIONS t

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, '. METALLURGICAL EVALUATIONS MAJOR-TASKS:

0 SURFACE EXAMINATIONS.

O NDE EXAMINATIONS 0 ETALL0 GRAPHIC EXMilNATIONS 0 FRACT0 GRAPHIC EXAMINATIONS O CHEMISTRY EVALUATIONS .

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l D F.sq t l of feaggggScheinalic illustration of the St Iine configuration showin9 he l i

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f

' ilcrizontal  ;

e Pipe End

,, s ..

8 ., Leak Location

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Pipe-End '- .>

L .

Light macrophotographs, schematically illustrating y .'~

the sectioning procedure employed for the leaked weld. .

.L 9 0' Clock 6 o' clock 3 0' clock

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

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6 0' Clock j hJ, N ID surface examination results of the elbow-to-horizontal pipe weld j

) joint showing the location of cracks seen on the elbow side and the pipe side. (3.25x)

l

SUMMARY

OF SURFACE EXAMlfjaI.LON RESULTS 6

0 SURFACE EXAMINATION RESULTS OF THE ID SURFACE OF THE WELD JOINT AT THE LEAK LOCATION CONFIRMED THE PRESENCE OF CIRCUMFERENTIAL CRACKS ONE ON EACH SIDE CF THE WELD. THE'

-CRACK ON THE PIPE SIDE WAS LOCATED AT THE WELD INTERFACE, MEASURED APPROXIMATELY THREE INCHES LONG, AND RAN INTO THE WELD METAL NEAR THE SIX O' CLOCK LOCATION OF THE PIPE. THE CRACK ON THE ELBOW SIDE WAS LOCATED IN THE COUNTERBORE REGION OF THE BASE METAL, RAN ALONG THE SURFACE MACHINING -

GROOVES, AND MEASURED APPROXIMATELY THREE' INCHES IN LENGTH.

e e

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y'i General morphology of' cracks seen on transverse sections taken at various locations along the weld.

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,  % *4 e f. ".~ s (Light Etch) (Macr > Etch)

I (Darkfield)

Light optical micrographs shown in different lighting conditions, j illustrating the location axi morphology of crack at the weld-to-pipe j interface ( F-2 3. 2 5 X )

W

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Light optical metallography results of the Section "C" illustrating the HAZ microstructures.

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(8x) (100x '- ,

, Illustration of the initiation of cracks at the ID surface machining groves in the counterbore region of the elbow.

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_--- ________ _ __ - ---r-

SUWARY OF t/ETALLOGRAPJJJC EXAMINATION RESULTS O METALL0 GRAPHIC EXAMINiTIONS CONDUCTED ON TRANSVERSE SECTIONS TAKEN AT SEV~1AL CIRCUMFERENTIAL LOCATIONS IN THE REGION OF CRACKING, Cih'4FIRNED THAT THE ID SURFACE CRACKING WAS EXTENDED DEEP INTO THE PIPE THICKNESS ALL THE WAY UP TO THE 00 SURFACE OF THE PIPE. ThE RESULTS SHOWED THAT THE MAJOR CRACK IN THE ELBOW SIDE INITIATED AT THE KNEE OF, THE COUNTERBORE REGION, PROGRESSED THROUGH THE BASE METAL AND TERMINATED IN THE WELD METAL. THE CRACK ON THE PIPE SIDE WAS INITIATED AT THE WELD METAL TO BASE METAL ll4TERFACE AND PROGRESSED THROUGH THE WELD METAL TOWARDS THE OUTSIDE DIAMETER SURFACE. THE CRACKING WAS PRIMARILY STRAIGHT AND TRANSGRANULAR IN CHARACTER. NO APPRECIABLE BRANCHING OP CRACK DEPCSITS WERE OBSERVED. f/ ETALLOGRAPHIC EXAMINATIONS CONDUCTED ON SEVERAL SECTIONS THROUGH THE MAJOR CRACKS FAILED TO CONFIRM THE PRESENCE OF ANY PAJOR DEFECTS IN THE WELD NETAL. THE METALLOGRAPHIC EXAMIFATIONS ALSO CONFIRMED THE PRESENCF OF SEVERAL FINE CRACKS INITIATED FROM THE MACHINED GROOVES OF THE COUNTERBORE REGION OF THE ELBOW.

THE OVERALL RESULTS OF THE METALL0 GRAPHIC EXAMINATIONS CONFIRMED THAT THE WELD CRACKING WAS INITIATED ON THE ID SURFACE AND PROGRESSED RADIALLY OUTWARDS TOWARD THE 00 SURFACE. THE CRACKING WAS DEEPEST (THROUGHWALL) NEAR 6 0' CLOCK LOCATION OF THE PIPE. THE CRACKING WAS PRIMARILY l CONTROLLED BY TENSILE LOADS AXIAL TO THE PIPE WITH NO APPRECIABLE CONTRIBUTION FROM ENVIRONMENTAL FACTORS.

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Light optical fractographs illustrating the fracture morphology of the cracks been in pieces B and D. (3.2Sx) k A i !N

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Scanning electron fractccraphs illust rating the fracture morphology of crack in piece "B"-

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t Scanning electron fractographs of tne endoxed we]d crack on the pipe

• side illustrating the evidence of fatigue striations.

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Light optical fractccraphs illustrating the positioning of various replica grids employed for the examination of the evidence for fatigue

striations in Samples B and D. (3 25x) i i

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) Replica transmission electron micrographs illustrating the typical i

appearence of the fatigue striations seen at grid location G in sample D.

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i 1 i l Replica transmission electron r.2icrographs illustrating the typical ,

appearence of the fatigue striations seen at grid location I in saniple D.

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' i Replica transmission electron micrographs illustrating the typical appearence of the fatigue striations seen at grid location F in sample B. l

)

SUMMARY

OF FRACT0 GRAPHIC EXAMINATION RESULTS i k

0 FRACTOGRAPHic EXAMlHATION OF THE FRESHLY OPENED CRACKS BOTH IN THE BASE METAL AND WELD METAL REGIONS SHOWED THAT THE CRACKING WAS INITIATED ON THE INSIDE DIAMETER SURFACE AND PROGRESSED RADIALLY OUTWARDS TO THE OUTSIDE DIANETER SURFACE. CRACKING APPEARS TO HAVE BEEN INITIATED AT SEVERAL LOCATIONS OVER A BROADER REGION OF THE 10 SURFACE-RATHER THAN FROM A SINGLE ISOLATED INITIATION SITE. THE ,

FRACTURE MORPHOLOGY FOLLOWED TRANSGRANULAR FACETS. HIGHER ,

MAGNIFICATION SCANNING ELECTRON FRACTOGRAPHY CONFIRMED THE PRESENCE OF FATIGUE STRIATIONS PROGRESSING.FROM THE INSIDE

, DIAMETER SURFACE TO ALL THE WAY TO THE CRACK llP NEAR OUTSIDE DIAMETER SURFACE. THE EVIDENCE OF FATIGUE l STRIATIONS WAS ALSO CONFlRMED IN THE FRESHLY OPENED CRACK IN THE WELD METAL. HIGH RESCLUTION TRANSMISSION ELECTRON i i MICROSCOPY CONDUCTED ON REPLICAS TAKEN FROM VARIOUS LOCATION THE ENDOXED FRACTURE FACES CONFIRMED THAT THE FATIGUE STRIATION SPACING RANGED FROM APPROXIMATELY ,

4X10-6 TO 8X10-6 INCHES.  !

t THE OVERALL RESULTS SUGGEST THAT CRACKING WAS lhlTIATED ON THE 10 SURFACE AND PROGRESSED RADIALLY OUTWARD TO THE 00.

, CRACKING OCCURRED BY HIGH CYCLE FATIGUE MECHANISM.

i t

1  !

l

( A p l E */ St PIrc rnRLCY St PIPC

~ .

Pks 100S 100$00 0 I ll ! I' N s 1005 IOUSEC H Illi U=8192 68-10E00 1 30 a 0 = 196, E U to U=16K II=1unEU 1 30 AuctoK00 to CRACK TIP FE CRACK TIP AREA 1A '

AREA 3A FC CR C P.

Mi HI Mt Ni si u Ab1A _ SI did A.

to.241. G i Io . 24TEliI

~

< u.coKLv xts < e.outrv ' xts (a) (a)

FAPLEY GI PIPE l6HLEY SI PIPE PR- S 109PCC G Illi PR= S 100Gl:C 0 l ai t U:0192 ll = t or.E U 1510 AU=10KEU 10 U:0192 ll=lerEU 3:10 AUzl0Kl u lu PHOTO 18, PHOTO 4, ARCA SC4ll FC HREA OCAN FC PIECE "E" CR PIECE "E" CR WELD CRACV. WCLD CPACr.

MI NI j Mt NI

< o os.ur u xs s J

d L.).A _

t o . 24nt e r

< o . oone v

- J$1A11___

.i.. n o . z e e. o . ,

(b) (b)

W Typical energy dispersive X-ray analysis results obtained f' rom tlie crack

/ deposits seen on the a) elbow and b) pipe cracks, in the "as orened" conditions.

6 1

CHEMISTRY ANALYSIS RESULTS OF THE ,

ID SURFACE DEPOSITS i (ELEMENT / COMPOUND  :

GMS/ AREA SWABBED) F CL P g N 8

! O3 04 .

CLEAN AREA' O 32 21.3 1.02 9.6 19.4 ID SURFACE 0.37 21.0 1.02 9.3 16.1 A

T NO EVIDENCE OF ANY CORROSIVE ELEENTS WAS' SEEN ON THE ID l, i

SURFACE i

l .

4 i

I I

1 i

I .

2 .

I b

I

~

SUMMARY

OF CHEMISTRY ANALYSIS RESULTS a

ELEMENT (WT 0/D) CR MN CU CO NI M0 P S SI C FE ELBOW MATERIAL 19.30 1.74 0.109 0.081 10.58 0.143 0.021 0.021 0.429 0.046 BAL HORIZ. PIPE 18.48 1.72 0.121 0.056 10.68 0.155 0.018 0.014 0.474 0.068 BAL WELD HETAL 19.86 1.33 0.158 0.10 10.10 0.154 0.016 0.013 0.376 0.022 BAL TYPE 304 S.

STEEL 18-20 2.0 -- --

8- --

0.045 0.03 1.0 0.08 BAL REQUIREMENTS Mx 10.5 Mx Mx TYPE 308 S.

STEEL STICK 19.5- 1.0- 0.75 --

9-11 0.75 0.03- 0.03 0.3- 0.08 BAL ELECTRODE 22 2.5 Mx' 10-12 Mx Mx Mx 0.65 Mx REQUIREMENTS 19.21 THE CHEMISTRY OF THE ELBOW AND PIPE MATERIALS MET THE TYPE 304 STAINLESS STEEL REQUIREMENTS.

THE CHEMISTRY OF THE WELD METAL MET THE TYPE 308 STAINLESS STEEL STICK ELECTRODE REQUIREMENTS.

'% C*

, '. SUWAflLDF CPEfilSTRY EVALUAT10N RESULTS

)

0 . CHEMISTRY EVALUATION OF CRACK DEPOSITS BY ENERGY DISPERSIVE X-RAY ANALYSIS FAILED TO CONFIRM EVIDENCE OF ANY AGGRESSIVE ELEMENTS CONTRIBUTING TO THE CRACKING PROCESS. WET CHEMISTRY ANALYSIS RESULTS OF THE PIPE, ELBOW AND WELD MATERIALS SHOWED THAT THE ELBOW AND PIPE MATERIALS MEET THE TYPE 304 STAINLESS STEEL REQUIREFENTS WHILE THE WELD METAL MEETS THE TYPE 308 STAINLESS STEEL REQUIREMENTS.

THE OVERALL RESULTS OF THE CHEMISTRY EVALUATIONS SHOWED THAT NO CORROSIVE ELEMENTS CONTRIBUTED TO THE CRACKING PROCESS AND THAT THE ELBOW, PIPE AND WELD MATERI ALS MEET THE SPECIFICATION REQUIREMENTS.

i i

l

. i j

1 i

3

(_bl

,-,-._--._7---., -- y ay-e_. ._

7 SUWARY OF MICR0 HARDNESS MEASOREfENT RESULTS AVERAGE APPROX.

KNDOP TENSILE STRENGTH HARDNESS (KSI)

ELBOW MATERIAL 160 70 PIPE MATERIAL 158 70 WELD METAL 207 91 NO ABNORf%LITIES IN THE STRENGTH LEVELS OF THE ELBOW, PIPE AND WELD MATERIALS f/2-

HAZ MICR0 HARDNESS MEASUREhENT RESULTS

[

i APPROX.

SERIAL DISTANCE KHN TENSILE NUMBER FROM CRACK 500 GMS STRENGTH 1 .005 238.2 107  ;

2 010 230.8 102

3 .015 210.7 92

4 .020 210.7 92  :

) 5 .025 211.7 93 i 6 .035 222.7 100

7 .055 236.9 107 8 .075 199.6 88 9 .095 192.1 85 10 .115 196.8 87 11 .135 172.8 77

] 12 .155 203.5 90 n

i EBLOW HAZ HAS A SLIGHTLY HIGHER HARDENER COMPARED TO THE UNAFFECTED BASE bETAL i

9

t SUfG%RY OF f/ICROPARDNESS 6EASUREbENT PES _ULTS O MICR0 HARDNESS MEASUREMENTS MADE ON THE POLISHED SECTION OF THE WELD JOINT SHOWED THAT THE MICR0 STRUCTURES OF THE ELBOW, WELD AND PIPE MATERIALS, RESPECTIVELY CORRESPONDED ~

TO KNOOP HARDNESS LEVELS OF 160, 207 AND 158. THESE HARDNESS VALUES CORRESPONDED TO AN APPROXIMATE TENSILE STRENGTH LEVELS OF 90 KSI IN THE WELD METAL AND 70 KSI IN THE PIPE AND ELBOW MATERIALS, NO ABNORMALITIES IN MECHANICAL PROPERTIES WERE SEEN, f

i r

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4

(

4 DIBERPYCHAfD.Sfj$

t 0 NO EVIDENCE OF BRANCHING, CRACK DEPOSITS OR CONTAMINANTS.

STRESS CORROSION IS NOT A fECHANISM, 0 NO EVIDENCE OF OVERLOAD DIMPLES.- OVERLOAD IS NOT'A fECHANISM, 3

0 NO WELD DEFECTS, HOT CRACKING OR OTHER WELD DEFECTS ARE NOT CCNTRIBUTING FACTORS. ,

I b

9 i

8 I

,, CONCLUSIONS 8

(

0 THE OBSERVED CRACKING IN THE FARLEY 2 SI LINE WELD WAS INITIATED AT THE ID SURFACE AND PROGRESSED RADIALLY t OU WARD TCWARDS THE OD SURFACE OF THE PIPE.

O THE CRACKING OCCURRED BY HIGH CYCLE FATIGUE E CHANISM, 1

0 MACHINING MARKS IN THE COUNTER BORE REGION (IN THE ELBOW) l AND THE WELD INTERFACE (IN THE PIPE) SERVED AS PREFERRED  ;

SITES FOR CRACK INITIATION,  !

O THE FATIGUE STRIATION SPACINGS ON THE FRACTURE FACE VARIED  !

j APPROXIMATELY BETkEEN 2 X 10-6 IN TO 8 X 10-6 ;g, i

j i

i r

i

~

i i

6) I 4  !

-NONDESTRUCTIVE EXAMINAT10N RESULTS j

. l i

0 FLUCRESCENT DIE PENETRANT TEST RESULTS OF THE ID SURFACE OF THE ELBOW TO VERTICAL PIPE l' ELD JOINT DID NOT REVEAL  ;

EVIDENCE OF ANY ID INITIATED CPACKING. ,

l 0 RT EXAMINATIONS RESULTS OF THIS WELD J0lNT SHOWED PRESENCE t

OF ACCEPTABLE LEVEL OF INCLUSION SITES IN THE ifLD.

O PT EXAMINATION RESULTS OF THE ID SURFACE OF THE ELBCW, 1 BOTH ON THE INTRADOS AND EXTRADOS REGIONS DID NOT SH&l l EVIDENCE OF ANY ID INITIATED CRACKING.

i i

CONCLUSION: THE ELBCW AND THE WELD JOINT #17 MAY NOT BE l SEEING THE LOADING CONDITIONS SEEN BY WELD #16 i

l l

~

)

IE.2 EVALUATIONS OF UNIT 2 B LOOP EXPERIENCE - D A'SFFV

2. OPERATIONAL TEST PROGRAM-A. SELECTION OF INSTRUMENTATION o ASSUMED CRACK RESULTED FROM FATIGUE MECHANICAL - VIBRATION THERMAL - STRATIFICATION & CYCLING o VIBRATION MEASUREMENTS: ACCELEROMETERS TYPE: PIEZOELECTRIC, ENDEVC0 7701-100 RANGE: 1 - 5000 HZ, 0 - 1000 g j o THERMAL MEASUREMENTS RTD'S i

TYPE: PLATINUM SURFACE RTD; HY-CAL: RTS-63 RANGE: - 100 U TO 9000F o STRAIN GAUGES NOT USED DUE TO INHERENT DIFFICULTIES WITH CYCLIC THERMAL LOADINGS i

1

)

J JY.2 B. SELECTION OF TEST LOCATIONS

, o VIBRATION LOOP B - CRACK LOCATION LOOP C - CONTROL MAXIMUM ANTICIPATED VIBRATION o THERMAL LOOP B - CRACK LOCATION LOOP C - CONTROL OUTSIDE WALL TEMPERATURE o LOOP C AS CONTROL LOOP A HAD ADDITIONAL RIGID RESTRAINT NEAR VALVE V051  !

1

LOOP C HAS LONGER HORIZONTAL RUN AND COULD l EXHIBIT MORE EFFECTS OF STRATIFICATION 1

LOOP A OR LOOP C ACCEPTABLE AS CONTROL, FINAL j CH0 ICE BASED ON COMTAINMENT ACCESS CONSIDERATIONS 1 ,

.j 6

O 1  :

i I I

e T

E.2 C.

SUMMARY

OF TEST RESULTS

1. VIBRATION FFT ANALYSIS TO OBTAIN PEAK SPECTRUM .

REVIEWED FREQ. RANGE 4-100 HZ MAXIMUM G LEVELS APPROX: .1 i

MAXIMUM DISPLACEMENT LEVELS: .00077 INCHES

. 2. THERMAL RESULTS PRIOR TO BIT FLOW DIVERSION  ;

LOOP B: LARGE STRATIFICATION i 0

215 F DOWNSTREAM }

0

! 128 F UPSTREAM l 4

LOOP B: TEMPERATURES FLUCTUATE SIGNIFICANTLY, PARTICULARLY AT BOTTOM 0F PIPE, PERIOD OF CYCLING BETWEEN 2 AND 20 MINUTES LOOP C: VERY LITTLE STRATIFICATION OR f FLUCTUATIONS l l

CONCLUSIONS  !

l LOOP C CONFIGURATION AS EXPECTED .

i LOOP B PROBABLY HAD SMALL FLOW 0F COOLER

WATER FLOWING INTO DOWNSTREAM PIPING  ;

1 I

W  !

N.2 D. EVALUATION OF CAUSE OF DOWNSTREAM THERMAL CYCLING o COOLER WATER IN SMALL QUANTITIES FLOWED INTO RCS PIPING AT VARIOUS RATES o FLOW REQUIRED A WATER SOURCE WITH GREATER THAN RCS PRESSURE (CHARGING SYSTEM) o TWO POSSIBLE CAUSES IDENTIFIED:

o VALVE 8885 LEAKAGE - 3" GATE o VALVE 8S11 LEAKAGE - 1" GLOBE - BYPASS LINE

i

, G. 2  :

E. BIT FLOW DIVERSION o LEAKAGE FLOW DIVERTED TO BIT SURGE TANK  !

o RTD READINGS INDICATE DOWNSTREAM STRATIFICATION AND CYCLING STOPPED ,

o NO CHANGE IN LOOP C READINGS j o TEMPORARY THERMAL CYCLING OBSERVED UPSTREAM ON LOOP B  !

o CURRENTLY STEADY-STATE RESPONSE ON ALL READINGS, l POSSIBLY FLOW IN LOOP B UPSTREAM l

i o CONCLUSION:

1 r FLOW DIVERSION HAS STOPPED COLD WATER l

FLOW TO ,1CS I

i MOST LIKELY CAUSE OF LEAKAGE WAS VALVE 8911 1

i i

l i  !

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b l l

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If.2 ,

+

l F. THERMAL - AFTER B. I. FLOW DIVERSION - CURRENT STATUS 1

l 0 LOOP B DOWNSTREAM STRATIFICATION AND TEMPERATURE FLUCTUATION l

! o LOOP C - NO EFFECT l

1 o INITIALLY OBSERVED LOW FREQUENCY THERMAL ,

OSCILLATIONS, UPSTREAM LOOP B 1

! o CURRENTLY LOOP B AND C STEADY STATE .

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II.3 ANALYTICAL EVALUATIONS - D.80T/'#

A. VIBRATION o CORRELATED SPECTRAL CURVES TO MODAL ANALYSIS o MAXIMUM STRESS ABOUT 500 PSI AT WELD o CONCLUSION: VIBRATION HAD NEGLIGIBLE EFFECT ON l OBSERVED PIPE CRACK B. COLD SPRING o SMALL AMOUNT OF COLD SPRING (ABOUT .6 INCH) EVALUAiED o LESS THAN 500 PSI AT WELD o CONCLUSION: NOT RELATED TO PIPE CRACK C. VALVE EFFECTS o VALVE LEAKAGE THROUGH SMALL GLOBE VALVE PRIMARY CAUSE OF CYCLING o THE EXPECTED OPENING AND CLOSING 0F THE CHECK VALVE (V051B) WITH A SMALL AP PROBABLY CAUSED THE FLUCTUATION IN THE THERMAL LOAD o BACK LEAKAGE AT CHECK VALVE CAN CAUSE STRATIFICATION l i

BUT NOT THERMAL CYCLING 1

o N0 KNOWN RELATIONSHIP BETWEEN CHECK VALVE PERFORMANCE AND MECHANISM OBSERVED s

E'.3 D THERMAL CYCLING EVALUATIONS ,

1. THERMAL STRESS ANALYSIS ,

a) DEVELOPMENT OF THERMAL LOADING i o FINITE ELEMENT CORRELATION OF OUTSIDE WALL TEMPERATURE AND INSIDE TEMPERATURE INDICATES t FULL TEMPERATURE CYCLING AND THREE MINUTE  ;

PERIOD REASONABLE ASSUMPTION  ;

o CONCLUSION:  ;

U 0 i REASONABLE TO ASSUME 550 TO 100 CYCLING l

REASONABLE TO ASSUME 3 MINUTE PERIOD i b) THERMAL CYCLING STRESSES o UNIFORM TEMPERATURE CYCLES APPLIED TO 2-D AXISYMMETRIC FINITE ELEMENT MODEL i o 0 MAXIMUM 5500 TO 100 STEP CHANGES,  !

3 MINUTE PERIOD o MAXIMUM MINIMUM STRESS PROFILE DETERMINED r

e IYi3 D. THERMAL CYCLING EVALUATION

2. FRACTURE MECHANICS / FATIGUE CRACK GROWTH i a) ANALYSIS BASED ON METALOGRAPHY o STRIATION SPACING USED TO ESTIMATE DA/DN VS T o DA/DN = CRACK GROWTH PER CYCLE f T = WALL THICKNESS l

o USE DA VS T CURVE TO ESTIMATE AK dK = RANGE OF STRESS INTENSITY

o USE K TO DETERMINE AS l

AS = RANGE OF APPLIED STRESS r 4 o OBTAIN CYCLES TO LEAKAGE i

b) ANALYSIS BASED ON THERMAL STRESS ANALYSIS i o THERMAL STRESS USCD IN FATIGUE CRACK ,

) GROWTH CALCULATION o DA/DN FOR AUSTENITIC STAINLESS STEEL l DA/DN = (2.42 X 10-20)(E)(6K)3.3

~

E = ENVIRONMENTAL FACTOR (2.0) o OBTAIN CYCLES 'TO LEAKAGE  ?

t

! CONCLUSION: STRESS PROFILE CALCULATED FROM STRIATION I i l j SPACING IS CHARACTERISTIC 0F THERMAL LOADINGS l l

l W

l .

i IT.3.

4

3. ASME FATIGUE EVALUATION o PURPOSE: CALCULATE USAGE FACTORS PER ASME CODE SECTION III, FOR SIS COLD LEG PIPING I o EVALUATION INCLUDED ALL CLASS 1 PIPING i

COMPONENTS ON 6" SIS COLD LEG LINES PLUS i

RCL N0ZZLE 1 4 o LOADINGS INCLUDED

.-

1 t

- -- DESIGN TRANSIENTS (SI, RHR, OBE, ETC.) t THERMAL CYCLING (B2, FORE AND AFTER B.I.

FLOW DIVERSION) o CONCLUSION.

ALL COMPONENTS SATISFY ASME REQUIREMENTS FOR  ;

l PLANT LIFE l I

l i

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4

)

1 i

i l l i l l }

I G. 4 CONCLUSION o PIPE CRACK WAS NOT CAUSED BY P00R FABRICATION / INSTALLATION /

MATERIALS o PIPE CRACK WAS NOT CAUSED BY ENVIRONMENTAL CONSIDERATIONS o PIPE CRACK WAS NOT CAUSED BY DESIGN LOADINGS j 0 PIPE CRACK WAS NOT CAUSED BY VIBRATION o PIPE CRACK WAS NOT RELATED TO CHECK VALVE l MAINTENANCE HISTORY I o CRACKING CAUSED BY FATIGUE DUE TO THERMAL LOADS 1

) o THERMAL LOADS RESULTED FROM THERMAL CYCLING COMBINED WITH

STRATIFICATION l 0 THERMAL CYCLING AND STRATIFICATION CAUSED BY COOLER WATER j FLOW FROM HIGH PRESSURE UPSTREAM SOURCE TO RCS I o COOLER WATER FLOW PROBABLY RESULTED FROM LEAKAGE I THROUGH 1" BIT BYPASS VALVE

o SIS COLD LEG PIPING SATISFIES ASME REQUIREMENTS j

i

4 L

i l i .

, f/ FLUID SYSTEMS EVALVATION OF-A AND.C. l j COLD LEG INJECTION LINES  ;

l 9 NDE PROVIDED NO EVIDENCE OF THERMAL. CYCLING ON A f

AND C LOOPS l 8 GIVEN THE AMOUNT OF IN-LEAKAGE, THE EVALUATION OF THE LOOP B TEMPERATURE TRACES CONCLUDES THAT THE  ;

} A AND C LOOPS WERE NOT EFFECTED i

t INSTRUMENTATION ON C LOOP DETECTED NO. THERMAL CYCLING l

! f 4 CONCLUSION: l 1 i Y

I LOOP B PROVIDED A PREFERRED LEAK PATH AND WAS i THEREFORE THE ONLY EFFECTED LINE.  :

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IN-LEAKAGE D ETjtERMAL SLEEVE ,4 ',y .. s

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- IN-LEAKAGEWASRklATIVELYSMAlt,$}lDUNABLE

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TO SWEEP TllE ENT!RE CROSS SECTION,0F THE 6" N .e , u HORIZ0f1TAL SI LINd ,'" .j '

RELATIVELY COLD FLUID WOULD HAVE TO TRAVEL' 22" ALONG THE' HORIZONTAL SECTION,AND 17" ALONG THEVERTICALSENTONBEFOREREACHINGTHE THERMAL SLEEVE .

THE VERTICAL SECTION JS CH4RACTERIZED BY SIGNIFICANT MIXING.0F FLUID GIVEN: *

'/

8 CIRCULATION.I!VE, TO NA10RAL' CONVE'CTION - - . ,

s ..

W  % ,A 0 PROXIMITY-T0 THE'DISCHAPGE OF-THE RCP y

~ .

m CONCLUSION: s GIVEN THE AMOUNT OF fN-LEAKAGE, DISPERSION EFFECTS '

IN THE HORIZONTAL AND VERTICAL PIPE SECTIONS

~~

PRECLUDES THE THERMAL' SLEEVE FROM EXPERIENCING THE~

~ '

THERMAL TRANSIENT

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OTHER LINES SUBJECT TO SIMILAR EXPERIENCES CRITERIA:

ANY ISOLATED LINE WHERE RELATIVELY COLD FLUID COULD BE INJECTED INTO THE RCS DUE TO AN IN-LEAKAGE FROM A HIGH PRESSURE SOURCE.

HIGH PRESSURE SOURCE:

THE CHARGING /SI SYSTEM IS THE ONLY ON LINE HIGH PRESSURE SOURCE CAPABLE OF INJECTING FLOW INTO THE RCS EURING NORMAL OPERATING PRESSURES.

OTHER LINES WHERE POTENTIAL MECHANISM EXISTS AUXlLIARY SPRAY LINE CHARGING OR ALTERNATE CHARGING LINES HHSI C. L. INJECTION LINES HHS1 H. L. INJECTION LINES 05023 RDM

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UXILIARY SPRAY LINE:

LEAKAGE'WOULD HAVE TO OCCUR ACROSS 8145-DELTA P ACROSS VALVE IS LOW (APPROXIMATELY_7 PSID)

IN-LEAKAGE TEMPERATURE IS APPR0XIMATELY 500*F CHARGING AND/0R ALTERNATE CHARGING LINES:

- LEAKAGE WOULD HAVE TO OCCUR ACROSS 8147, 8146, OR 8392 DELTA P ACROSS VALVES IS (APPR0XIMATELY 7 PSID)

IN-LEAKAGE TEMPERATURE IS APPR0XIMATELY 500*F

~

HHSI C, L, AND H L, INJECTION LINES:

- LEAKAGE WOULD HAVE TO OCCUR ACROSS VALVES 8885, 8886, 8884 OR 8911 DELTA P ACROSS VALVES IS APPR0XIMATELY 320 PSID IN-LEAKAGE TEMPERATURE IS APPR0XIMATELY 100*F 05023,RDM

QUALITATIVE EVALVATION OF VALVE LEAKAGE THREE PRIMARY FACTORS EFFECTING PROBABILIT.Y 0F VALVE TO MAINTAIN A SECURE PRESSURE B0UNDARY t VALVE TYPE 4 VALVE OPERATOR S DELTA P VALVE TYPE 9 GATE VALVE IS HIGHLY RELIABLE 9 GLOBE VALVE IS SLIGHTLY LESS RELIABLE THAN GATE VALVE OPERATOR e MOV PROVIDES THE TIGHTEST AND MOST REPEATABLE SEAT 4 AIR OPERATOR IS SLIGHTLY LESS EFFECTIVE e MANUAL VALVES ARE LEAST LIKELY TO MAINTAIN f A SECURE PRESSURE BOUNDARY a

DELTA P  :

0 LOWER DELTA P REDUCES LIKELlH00D OF VALVE LEAKAGE I 05023.RDM /

(gg1 1

VALVE CHARACTERISTICS .

RELATIVE P RO BABI'_.lTY MAX OF VALVE SIZE TYPE OPERATOR AP LEAKAGE 8145 2" GLOBE AIR 7 PSID LOW 8147 3" GLOBE AIR 7 PSID LOW 8146 8392 3/4" GLOBE MANUAL 7 PSID LOW-MED i

8885 3" GATE MOV 320 PSID LOW

8884 8886 Q 8911 1" GLOBE MANUAL 320 PSID MED hj

.______________~____

i EVALUATION OF INDIVIDUAL LINES AUXILIARY SPRAY LINE LOW PROBABILITY OF IN-LEAKAGE' 8 LOW DELTA P 0 RELIABLE PRESSURE B0UNDARY IN-LEAKAGE INITIATES-AT A RELATIVELY HIGH TEMPERATURE PRESENCE OF COLD TRAP DOWNSTREAM 0F LAST CHECK VALVE REDUCES TEMPERATURE GRADIENT ACROSS THE VALVE CONCLUSION:

THE AUXILIARY SPRAY LINE DOWNSTREAM 0F LAST C.V IS

. NOT SUBJECT TO THERMAL CYCLING l

05023 RDM s s

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An111 Dry Spray injection Line to Normal Spray Line 9

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LOW-PROBABILITY OF IN-LEAKAGE-0 LOW DELTA P 0 RELI ABLEL PRESSURE BOUllDARY Ill LEAKAGE If1ITIATES AT A RELATIVELY HIGH TEMPERATURE

- CHARGING LINES ARE INSULATED, THEREFORE C00LDOWN OF IN-LEAKAGE PRIOR TO INJECT 10fl INTO RCS IS MINIMlZED' CONCLUS!0N:

EVALUATI0fl SUGGESTS THAT THERMAL CYCLING IS HIGHLY UNLIKELY 05023,RDM

. HHSI H L,.-AND C, L. INJECTION LINES LOW PROBABILITY OF IN-LEAKAGE 9 H. L. INJECTION LINE PRESSURE BOUNDARY ,

IS PROVIDED BY MOV GATE VALVES  !

O WITH 8801A/B OPEN, THE C. L. INJECTION .

LINE PRESSURE BOUNDARY IS PROVIDED BY M0V GATE VALVE .

CONCLUSION:

/cTHOUGH THE POTENTIAL MECHANISM EXISTS ON THE H. L, INJECTION LINES THE PROBABILITY OF THERMAL ,

CYCLING IS MINIMlZED GIVEN A SECURE PRESSURE B0UNDARY,

• WITH LEAKAGt THROUGH THE BIT BYPASS LINE DIVERTED, THE C. L. INJECTION LINE HAS AN EQUALLY SECURE PRESSURE B0UNDARY, PROBABILITY OF THERMAL CYCLING IS MINIMlZED,  ;

I I

05023,RDM '

36 .2 THERMAL SLEEVE CONSIDERATIONS o

SUMMARY

OF CURRENT PLANT STATUS o THERMAL SLEEVES INCORPORATED IN ORIGINAL DESIGN TO PROTECT PRESSURE BOUNDARY FROM THERMAL SHOCK o ANALYTICAL METHODS AVAILABLE AT TIME OF ORIGINAL DESIGNS NOT ABLE TO EVALUATE STRUCTURAL INTEGRITY OF COMP 0NENT-0 FINITE ELEMENT TECHNIQUES AND IMPROVEMENTS IN ASME CODE ANALYSIS PERMITTED Q'!ALIFICATION OF N0ZZLE WITH AND WITHOUT SLEEVE o FARLEY SIS N0ZZLES QUALIFIED WITH AND WITHOUT SLEEVES ,

o RECOMMENDATION MADE TO ELIMINATE SLEEVE FROM DESIGN o ANALYSIS OF RECORD CONSIDERED DESIGN TRANSIENTS j o THERMAL MIXING CONSIDERED BUT INSUFFICIENT AT 1 IN N0ZZLE REGION TO CAUSE FATIGUE i

o SIS LOOP B THERMAL CYCLING DID NOT HAVE IMPACT ON N0ZZLE IMTEGRITY l

0 PRELIMINARY THERMAL HYDRAULIC EVALUATION DEMONSTRATE FLOW MIXING IN VERTICAL RISER BEFORE N0ZZLE REGION o THIS IS SUPPORTED BY LACK 0F INDICATION IN 1

DOWNSTREAM WELDS  !

V .2 o UT ON N0ZZLE SAFE-END WELD FOUND NO RECORDABLE INDICATIONS o UT/RT/AND PT ON DOWNSTREAM (INSIDE AND OUTSIDE SURFACES) ELBOW WELD FOUND NO INDICATION OF CRACK ,

i o PREVIOUS STUDY'S CONCLUDED THERMAL SLEEVE FAILURE RESULTED FROM FLOW INDUCED VIBRATION i

o VIBRATION LOADS ON CRACKED WELD RESULTING FROM THE SLEEVE PROTRUDING INTO THE RCS FLOW HAVE BEEN EVALUATED AND ARE NOT CONSIDERED PROBABLE SOURCES l 0F FATIGUE 0 CONCLUSIONS l

o N0ZZLE INTEGRITY NOT AFFECTED BY SIS LOOP B i THERMAL MECHANISM, WITH OR WITHOUT SLEEVES o THERMAL SLEEVE INTEGRITY PROBABLY NOT RELATED

'TO SIS LOOP B THERMAL MECHANISM  :

i

V .3 CONTINUED ACCEPTABILITY 0F UNITS 1 AND 2 i o SYSTEMS DESIGN EVALUATION INDICATES SIS COLD LEG MOST LIKELY CANDIDATE o NDE ON PIPING COVERED ALL MOST SUSCEPTIBLE REGIONS WITH NO RECORDABLE INDICATIONS i o UNIT 2 CYCLING MECHANISM ELIMINATED o UNIT 1 SCHEDULED FOR OUTAGE IN MARCH:

NDE FOUND NO RECORDABLE INDICATIONS INSUFFICIENT TIME FOR THERMAL CYCLING TO ,

PROPAGATE CRACK THROUGH-WALL f

o PRELIMINARY LEAK-BEFORE-BREAK EVALUATIONS INDICATE NO DOUBLE END BREAK PRIOR TO LEAK  !

DETECTION i

I J l

07 08l RTD's 01

- 09 10 02

- AS RTD's 03

^

A3 r RTD's 6-10 2,, HHSI 04 g

TD's 1-5 05 A4 V0513

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RTD's q i

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14

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\ A9 ,2" HHSI Cold. Leg 8 Al IDENTIFICATION OF INSTRLHENTATION

j RTD61 RTD96_

1. 440*F 1. 245'T

2. 500*F ,

2. 260*F

3. 495'F p 3, 200*F y  !

VALVE V051B 6" SI/RHR TO B COLD LEG l'

RTD65 RTD19

1. 225'T 1. 117'F

2. 490*F 2. 200*F

3. 490'F 3. 115'T B LOOP COLD LEG RTD13 RTD11

1. 455'F 1. 402*F

2. 455'T 2. 401*F

3. 453* F 3. 400*F y VALVE V051A hf .. LEG RTD12 RTD14

. 1. 450'F 1. 360*F

2. 447'T 2. 360'T

3. 443*F 3. 358'F

1. PRIOR TO BI FLOW DIVERSION

2. INTERDI CYCLING AFTER FLOW DIVERSION

3. AFTER BI FLOW DIVERSION LONG TERM o r AVERAGE TEMPERATURES DURING CYCLING C LOOP COLO LEG U'll 1

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FARLEY SIS CL TEMPERATURE PROFILE B LOOP DOWNSTR AM PRIOR TO BI FLOW DIVERSION _

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O O LOOP B 450 DOWNSTREAll TOP

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l FARLEY SIS CL TEMPERATURE PROFILE l PRIOR TO BI FL0ll DIVERSION I '

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FARLEY SIS CL TEf1PERATURE PROFILE PRIOR TO BI FLOW DIVERSION LOOP C 500 i

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TOP 01 02 FARLEY SIS CL TEMPERATURE PROFILE 03l si ; '

PRIOR TO SI FLOW DIVERSION 04 500 05 i

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FARLEY SIS CL TEMPERATURE PROFILE .

DEC. 28 LP B UPSTREAM PRIOR TO BI FLOW DIVERSION 500

<50 400 p 350 e 300 Q.

2 TOP 250 __

i 200 LOOP B UPSTREAtt 150 l

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BOT _. TOM l ) 100 10.7 10.9 11.1 11.3 11.5 11.7 11.9 12.1 12.3 12.5 12.7 UP TOP UP BOTTOM l

FARLEY SIS CL TEMPERATURE PROFILE .

DEC. 28 LP c PRIOR TO BI FLOW DIVERSION 500 TOP

~

LOOP C r v x---_-- v-%

450

% ,f 9w ,9 f q %v gy ~ n' v%W DOWNSTREAM '

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TIME (HOURS)

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UP TOP --

UP BOT 4

TOP 01

.02 03i Down- l FARLEY SIS CL TEMPERATURE PROFILE DURING BI FLOW DIVERSION 04D 05 550 80TTM 500 QAu-qeM-h-w-@

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- RID 01 RfD02 RID 03 RID 04 RID 05 I .

..___________________a _

e-FARLEY SIS CL TEMPERATURE PROFILE

~

INTERIM CYCLING AFTER FLOW DIVERSION 550 W h

~

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M M N' ~ --4 eW'# -

BOTT0F LOOP B DOWNSTREAM 450 400 C

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a 300 .

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FARLEY SIS CL TEMPERATURE PROFILE -

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4 EVALUATION F THE EFFECT OF REDUCED SAFETY IlWECTION FLOW CORRESPONDING TO SPILLIIIG TO CONTAll#ENT BACKPRESSURE ON THE 1

JOSEPH M. FARLEY SMALL INtEAK LOCA ANALYSIS 4

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BACKGROUND

• Crack in SI line led to questions concerning Farley S8LOCA analysis of record (WFLASH)

• Review noted that the Farley WLASH analysis inappropriately spflied the 6-inch break to  !

RCS backpressure, not containment pressure

• Evaluation conducted to determine effect of the inappropriate spillage assumption

• This evaluation revealed an additional finding of an incorrectly reported PCT in the Farley FSAR I

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JOSEPH M. FARLEY ECCS HIGH HEAD INJECTION CURVES i

(Minimum safeguards, 1 Pump Operating, 1 Line spilling) l l

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2000=

Broken Loop Spilling To RCS Backpressure l 1500=

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- l EVALUATION RESULTS

• Increase of PCT by 45.7'F due effects of earlier core uncovery and delayed recovery time (3<84 seconds)

• Increase of PCT by 9'F due to are precise reading of computer analysis output instead of sunnary sheets SU M ARY PCT TABLE UNIT 1 UNIT i FSAR 1703*F 1820'F reporting +9'F +9'F correction spillage 46*F M6*F correction ,

FSAR (proposed) 175B'F 1875'F i

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Conclusion:

considerable umrgin still exists to 2200*F 10CFR50.46 lisit and l to the LBLOCA analysis result of 2013'F

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APCo ACTIONS )

• Letter to NRC detailing evaluation and results dated January 14, 1988

• Safety Evaluation for FSAR change approved by PORC January 14, 1988

• Change to be incorporated into FSAR at next appropriate revision ,

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