ML20217A828

Rev 2 to Final Rept, Repair of 3/4 O.D. SG Tubes Using Leak Tight Sleeves

ML20217A828
Person / Time
Site:	San Onofre
Issue date:	06/30/1997
From:	ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY
To:
Shared Package
ML20046D781	List: ML20046D780 ML20217A818 ML20217A823 ML20217A828 ML20217A837
References
CEN-630-NP, CEN-630-NP-R02, CEN-630-NP-R2, NUDOCS 9709230006
Download: ML20217A828 (163)

Text

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CEN-630-NP l

Revision 02 i

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i l-COMBUSTION ENGINEERING INC, i

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June,1997 l

Repair of 3/4" O.D.

e Steam Generator Tubes Using Irak Tight Sleeves FINAL REPORT 1

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Combustion Engineering, Inc.

Nuclear Operations 1

Windsor, Connecticut 7% p p 9709230006 970916 2

POR ADOCK 05000361 P

PDR

T LEGAL NOTIC11 Tills REPORT WAS PREPARED AS AN ACCOUNT OF WORK SPONSORED BY ABB COMBUSTION ENGINEERING. NEITilER ABB COMBUSTION ENGINEERING NOR ANY PERSON ACTING ON ITS BEllALF:

A.

MAKES ANY WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED INCLUDING TiiE WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE OR MERCIIANTABILITY, WITil RESPECT TO Tile ACCURACY, COMPLETENESS, OR USEFULNESS OF TiiE INFORMATION CONTAINED IN Tills REPORT, OR TIIAT Tile USE OF ANY INFORMATION, APPARATUS, METilOD, OR PROCESS DISCLOSED IN i

TIIIS REPORT MAY NOT INFRINGE PRIVATELY OWNED RIGilTS; OR B.

ASSUMES ANY LIABILITIES WITil RESPECT TO Tile USE OR FOR DAMAGES RESULTING FROM Tile USE OF, ANY INFORMATION, APPARATUS, METilOD OR PROCESS DISCLOSED IN Tills REPORT.

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ABSIIMCI A technique is presented for repairing degraded steam generator tubes in pressurized water reactor Nuclear Steam Supply Systems (NSSS). The technique described alleviates the need i

for plugging steam generator tubes which have become corroded or are otherwise considered to have lost structural capability. The technique consists of installing a thermally treated Alloy 690 sleeve which spans the section or sections of the original steam generator tube which requires repair. The sleeve is welded to the tube near each end of the sleeve for repairs at the tube support plates or welded at the upper end and lower end or welded at the upper end and hard rolled at the lower end for repairs to the steam generator tube in the tube sheet region.

This report details analyses and testing performed to verify the adequacy of repair sleeves for installation in a 3/4 inch 0.D. nuclear steam generator tube. These verifications show tube sleeving to be an acceptable repair technique.

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TABLE OF CONTENTS Sec11on Iltle Eage

1.0 INTRODUCTION

11 1.1 PURPOSE l1

1.2 BACKGROUND

12 1.3 ACRONYMS 12 2.0 SUhfMARY AND CONCLUSIONS 21 3.0 ACCEPTANCE CRITERIA 31 4.0 DESIGN DESCRIPTION OF SLEEVES AND INSTALLATION EQUIPMENT 41 4.1 SLEEVE DESIGN DESCRIPTION 41 4.2 SLEEVE MATERIAL SELECTION 4-1 4.3 SLEEVE-TUDE ASSEMBLY 42 4.4 PLUGGING OF A DEFECTIVE SLEEVED TUDE 43 4.5 SLEEVE INSTALLATION EQUIPMENT 4-3 4.5.1 Remote Controlled Maninulator 4-4 4.5.2 Tool Delivery Equinment 4-4 4.5.3 Tube Brushing - Cleaning Eaulpment 45 4.5.4 Tube Rolling Eauioment 45 4.5.5 Sleeve Exnansion Equinment 4-6 4.5.6 Slecle Welding Eauipment 46 4.5.7 Nondestructive Examination 4-7 11

IABI II OF CONTENTS (Continued)

Secilon Iitic Page 4.5.8 PoshW11d_llcaLItcatment liquipinent 47 4.5.9 Sleeve Rolling Eaulpinent 47 4.6 ALARA CONSIDERATIONS 48

4.7 REFERENCES

TO SECTION 4.0 49 5.0 SLEEVE EXAMINATION PROGRAM 51 5.1 ULTRASONIC INSPECTION 52 5.1.1 Summary and conclusions 52 5.1.2 Ultrasonic Evaluation 53 5.1.3 Test Eaulnment

_53 5.2 EDDY CURRENT INSPECTION 5-4 5.2.1 Hnckground 54 5.2.2 Plus Point Probe Quallriention Study 55 5.3 VISUAL INSPECTION 5-6 5.3.1 summary and conclusions 5-6 5.3.2 cienning inanection 5-7 5.3.3 Weld 1hamination 5-7

5.4 REFERENCES

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- - -. - ~. - -.. - -

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l TABI II 01: CONTI:NTS (Continued) i Sec11on Iltic Page 6.0 SLEEVE-TUHE CORROSION TEST PROGRAM 6-1 1

6.1

SUMMARY

AND CONCLUSIONS 61 6.2 TEST DESCRIPTION AND RESULTS 61 i

6.2.1 lirimary Side tests 61 J

6.2.1.1 Pure Water Stress Corrosion Cracking Tests 63 J

j 6.2.1.2 Above the Tubesheet (ATS) Weld Capsule Tests 6-3 4

i 6.2.1.3 TSP Sleeve Weld Capsule Tests 6-4 6.2.1.4 Summary Primary Coolant Corrosion Performance 65 6.2.2 Secondary Side Tests 67 i

6.2.2.1 Modified liuey Tests 6-7 6.2.2.2 Capsule Tests 67 6.2.2.3 Sodium Ilydroxide Fault Autoclave Tests 68 i

j 6.2.2,4 Summary 6-9

6.3 REFERENCES

FOR SECTION 6.0 6 10 i

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IA131E 01: CONTENTS (Continued)

Section Iltle Page 7.0 MECilANICAL TESTS OF SLEEVED STEAM GENERATOR 7-1 i

TULLES 7.1

SUMMARY

AND CONCLUSIONS 71 7.2 CONDITIONS TESTED 71 7.3 WELDED SLEEVE TEST PARAMETERS AND RESULTS 7-1 7.3.1 Axial Pull Tests 71 7.3.2 Collanse Testing 72 7.3.3 Iturst Testing 73 7.3.4 Load Cycling Tests 73 8.0 STRUCTURAL ANALYSIS OF SLEEVE-TUHE ASSEMBLY 81 8.1

SUMMARY

AND CONCLUSIONS 81 8.1.1 Design Siring 81 8.1,2 Detailed Analysis Summary 81 8.2 LOADINGS CONSIDERED 8-7 8.2.1 IJpper Tube Weld Pull-Out Load 87 8.2.2 Lower Sleeve Rolled Section Push Out Load 88 8.2.3 Weld Fatipus 88 v

TABI E OF CONTENTS (Continued)

Section Illic Page 8.3 EVALUATION FOR ALLOWADLE SLEEVE WALL 8-8 DEGRADATION USING REGULATORY GUIDE 1.121 8.3.1 Normal Ooeration Safety Margins 88 8.3.2 Postulated Pipe Repture Accidents 8 10 8.3.3 Arcrage Minimum Weld lleight Requirements 8-11 8.4 EFFECTS OF TUDE LOCK-UP ON SLEEVE LOADING 8 13 8.4.1 Sleeved Tilbe in " Worst" Case ABB/CE Plant. FreeAgg Crate 8 13 8.4.2 Sleeved Tube in " Worst" Case Westinghnute Plant. Free at SuppoILPlate 8-14 8.4.3 Sleeved Tube in " Worst ' Case ABB/CE Plant.

8-15 lark-un at First Egg Crate 8.4.4 Sleeved Tube in " Worst" Case Westinghnuse Plant.

8-15 lark-un at First Support 8.4.5 Effect of Tube Prestress Prior to Sleeving 8-22 8.4.6 Lower Sleeve Rolled or Weld Section PuchonL 8 22 Due to Restrained Thermal Ernancion 8.5 SLEEVED TUBE VIBRAT;ON CONSIDERATIONS 8-23 8.5.1 Effects of increased Stiffness 8 23 8.5.2 Effect of Severed Tube 8 23 8.5.3 Seismic Evaluation 8 25 8.6 STRUCTURAL ANALYSIS FOR NORMAL OPERATION 8-27 8.6.1 Fatigue Evaluation of Upper Sleeve / Tube Weld 8-27 8.6.2 Fatigue Evaluation of Lower Sleeve Rolled Section 8 31 vi

- - - _ = _ -

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IA13LE OF CONTENTS (Continued) i Section lille Eage j

8.7 REFERENCES

FOR SECTION 8.0 8 34 1

8A FATIGUE EVALUATION OF UPPER TUDE/ SLEEVE WELD 8A-1

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8B TUBE SLEEVE IllSTORY DATA 8B 1 9.0 SLEEVE INSTALLATION VERIFICATION 9-1 i

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9.1

SUMMARY

AND CONCLUSIONS 91

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9.2 SLEEVE-TUDE INSTALLATION SEQUENCE 9-1 J

9.2.1 Exnansion/ Roll Transition Zone Sleeve With Rolled Lower Joint 91 9.2.2 Tube Suonort Sleeve 92 l

9.3 WELD INTEGRITY 92 l

9.3.1 Cleaning Oualification 92 1

9.3.2 Exnansion Qualification 9-3 i

9.3.3 Weld Oualificatlan 9-3 9.3.4 Ultrasonic Testing Qualification 9-4 9.3,5 Post Weld Ilcat Treat Qualification 9-4 f

9.3.6 Summarv 9-6 9.4 ROLLED JOINT INTEGRITY 97 i

9.5 COMMERCIAL SLEEVE INSTALLATION 9-7

9.6 REFERENCES

FOR SECTION 9.0 9-7 10.0 EFFECT OF SLEEVING ON OPERATION 10-1

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LIST GILIAllLIIS Table No.

Iahic l'AEC 1-1 ACRONYMS USED IN REPORT l-3 2-1 INSTALLATIONS OF ABB CE WELDED SLEEVES 2-3 3-1 REPAIR SLEEVING CRITERIA 32 51 ACRONYMS USED IN ET ANALYSIS 58 6-1 STEAM OENERATOR TUBE SLEEVE CORROSION TESTS 6-2 62 SLEEVE /TUDE CAPSULE SCC TESTS 6-4 6-3 SECONDARY SIDE STEAM GENERATOR TUBE SLEEVE 68 CAPSULE TESTS 7-1 SLEEVE-TUDE ASSEMBLY MECilANICAL TESTING 75 RESULTS 81

SUMMARY

OF SLEEVE AND WELD ANALYSIS RESULTS 8-4 82

SUMMARY

OF LOWER JOINT (WELDED AND ROLLED)

DESIGN, ANALYSIS,AND TEST RESULTS 8-6 8-3A 26 INCil SLEEVE AX1AL MEMBER PilYSICAL-PROPERTIES FOR " WORST" CASE ABB/CE PLANT 8-16 8 3B 26 INCil SLEEVE AXIAL MEMBER PliYSICAL PROPERTIES FOR " WORST" CASE WESTING 110USE PLANT 8-17 8-4A AXIAL LOADS IN SLEEVE WITil TUBE HQI LOCKED INTO EGG CRATE FOR " WORST" CASE ABB/CE PLANT 8-18 8-4B AXIAL LOADS IN SLEEVE WIT 11 TUBE NOI LOCKED INTO TUBE SUPPORT FOR " WORST" CASE WESTING 110USE 8-19 PLANT viii

I LIST 011 TABLIM (Continued)

Table No.

hble Pagc i

8 5A AXIAL LOADS IN SLEEVE WITil TUBE LOCKED INTO 8 20 EGG CRATE FOR " WORST

• CASE ABB/CE PLANT I

8 5B AXIAL LOADS IN SLEEVE WITil TUBE LOCKED INTO 8 21 TUBE SUPPORT FOR

• WORST" CASE ENVELOPMENT 8-6

. UPPER SLEEVE WELD TRANSIENTS CONSIDERED FOR 8 29 AN ABB/CE PLANT 8-7 UPPER SLEEVE WELD TRANSIENTS CONSIDERED FOR 8 30 A WESTINGilOUSE PLANT j

8-8 LOWER SLEEVE SECTION TRANSIENTS CONSIDERED FOR 8 32 AN ABB/CE PLANT f

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89 IAWER SLEEVE SECTION TRANSIENTS CONSIDERED FOR 8-33 I

A WESTINGilOUSE PLANT i

8A 1A STRESS RESULTS,100% STEADY STATE 8A-4 8A 1B STRESS RESULTS,15% STEADY STATE 8A-5 t

8A lC STRESS RESULTS,0% STEADY STATE 8A 6 i

8A ID STRESS RESULTS FEEDWATER CYCLING 8A 7 l

8A-2A RANGE OF STRESS AT WORST LOCATION 8A 8 8A-2B FATIGUE EVALUATION AT WORST LOCATION 8A 9 8A 3A STRESS RESULTS,100% STEADY STATE (0,020" Weld) 8A-11 8A 3B ST!tESS RESULTS,15% STEADY STATE (0.020" Weld) 8A-12 8A-3C STRESS RESULTS,0% STEADY STATE (0.020" Weld) 8A-13 1

8A 3D STRESS RESULTS FEEDWATER CYCLING (0,020" Weld) 8A-14 a

8A-4A RANGE OF STRESS AT WORST LOCATIONS (0.020" Weld) 8A-15 i

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1 1 lST OE. TAB 1FM (Continued) i Table Na Iable Pagc i

8A 4B FATIGUE EVALUATION AT WORST LOCATIONS (0.020" Weld) 8A 16 f

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91 0.875 0.D. SLEEVED TUBE PWilT DATA 99 I

92 0.750" O.D. SLEEVED TUDE PWilT DATA, 9 10 i

TUBES LOCKED AT ALL SUPPORTS 93 ABB CENO S/O SLEEVE OPERATING lilSTORY 9 !!

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10 1 I{YDRAULIC EQUIVALENCE RATIOS 10 2

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LIST Ol I:lGURES Figure No.

Ihic Eage 41 EXPANSION / ROLL TRANSITION ZONE SLEEVE 4 10 42 TUBE SUPPORT SLEEVE 4 11 l

l 43 EXPANSION / ROLL TRANSITION ZONE 4 12 SLEEVE INSTALLATION 44 TUBE SUPPORT SLEEVEINSTALLATION 4 13 45 MANIPULATOR AND TOOL DELIVERY SYSTEM 4 14 46 TOOL DELIVERY EQUIPMENT 4 15 47 TUBE CLEANING EQUIPMENT 4 16 48 SLEEVE EXPANSION EQUIPMENT 4 17 49 SLEEVE WELDING IIEAD ASSEMBLY 4 18 4 10 SLEEVE WELDING llEAD POWER SUPPLY UNIT 4 19 4-11 ULTRASONIC TEST EQUIPMENT 4 20 4 12 VISUAL TEST EQUIPMENT 4 21 4 13 POST WELD IIEAT TREAT EQUIPMENT 4 22 4 14 SLEEVE ROLLING EQUIPMENT 4 23 51 NDE PROCESS FLOW CllART 59 52 ET PROCESS FLOW CIIART 5 10 53 UT B SCAN - ACCEPTABLE 5 11 5-4 UT B SCAN REJECTABLE 5-12 5-5 UT PROBE 5 13 5-6 UT CALIBRATION STANDARD 5 14 xi

f 1.lST OF FIGURES (Continued)

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Figure No.

Ihic Eage 61 PURE WATER CORROS10N TEST SPECIMEN 6 11 a

j 62 ATS WELD CAPSULE TEST SPECIMEN 6 12 i

63 TSP WELD CAPSULE TEST SPECIMEN 6 13 j

64 CAUSTIC CORROSION AUTOCLAVE TEST SPECIMEN 6 14 i

81 WELDED SLEEVE /TUDE ASSEMBLY 8 35 8-2 SYSTEM SCllEMATIC FOR " WORST" CASE ABB/CE PLANT 8 36 i

j 83 SYSTEM SCIIEMATIC FOR

• WORST" CASE WESTINGilOUSE 8-37 i

PLANT 8-4 STIFFNESS MODEL OF SLEEVE AND LOWER TUBE 8-38 85 STIFFNESS MODEL OF UPPER TUBE AND SURROUNDING TUBE 8-39 86 FINITE ELEMENT MODEL OF UPPER TUBE WELD 8-40 SA 1 NODE AND STRESS CUT IDENTIFICATION 8A 3 8A-2 NODE AND STRESS CUT IDENTIFICATION FOR 20 MIL WELD 8A-10 91 POST IIEAT TREAT BRUSilED SECTION 9 12 3

l 92 0.875 0 D. LOCKED TUBE TEST 9 13 i

i 93 0.875 0.D. LOCKED TUBE TEST, 9-14 i

TEMPERATURE AND AX1AL LOAD PROFILE a

9-4 0.750 0.D. LOCKED TUBE MOCKUP 9 15 95 0.750 0. D. TYPICAL TEMPERATURE PROFILES 9-16 i

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LIST OP APPENDjCES Appendix No.

No. Pages l

A PROCE5iS AND WFl.D OPERATOR QUAL IFICAT10N A1 A.1 SLEEVE WELDING AND SLEEVE WELDER A1 QUALIFICATION A.2 REFERENCES TO APPENDIX A A1 1

xiii

EORWARD As noted in this topical report, Cl!N 630 P, " Repair of 3/4" O.D. Steam Generator Tubes Using Leak Tight Sleeves", the tooling and methods described represent the current technology implemented for sleeve installation and inspection. As technological advances are made in sleeve installation and/or inspection techniques, the new tooling and/or processes may be utilized after they have been laboratory verified to provide improved sleeve installation methods, or after a suitable qualification program has demonstrated improved performance.

Such advances / improvements may

• .e implemented provided that they do not involve alternative joining technology or alternative sleeve material, and provided that the 10CFR50.59 process has demonstrated that no unreviewed safety question will be created.

The 10CFR50.59 process will be performed under the licensee's program.

xiv

1.

INTRODUCTION 1.1 PURPOSE The purpose of this report is to provide information sufficient to support a technical specification change allowing installation of repair sleeves in 3/4" O,D. tube steam generators including; ABB CENO designed steam generators and Westinghouse designed Series D and E steam generators. This report demonstrates that reactor operation with sleeves installed in the steam generator tubes will not increase the probability or consequence of a postulated accident condition previously evaluated. Also it will not create the possibility of a new ar different kind of accident and will not reduce the existing margin of safety.

ABB Combustion Engineering (ABB-CE) provides two types ofleak tight sleeves for repair of 3/4 inch 0.D. steam generator tubes with full depth rolled or expanded tubesheet joints. The first type of sleeve spans the parent steam generator tube at the top of the tubesheet. This sleeve is welded near the upper end and hard rolled into the tube within the steam generator tubesheet. The steam generator tube with the installed sleeve meets the structural requirements of tubes which are not degraded.

The second type of sleeve spans degraded areas of the steam generator tube at a tube support or in a free span section of tube. This leak tight sleeve is welded to the steam I

generator tube near each end of the sleeve. The steam generator tube with the installed welded sleeve meets the structural requirements of tubes which are not degraded.

Design criteria for all types of sleeves were prepared to ensure that all design and licensing requirements are considered. Extensive analyses and testing have been performed on the sleeve and sleeve to tube joints to demonstrate that the design critt ria are met.

The effect of sleeve installation on steam generator heat removal capability and system flow rate are 6ussed in this report. IIeat remova! capability and system flow rate was considered ft, tetallation of one to three sleeves in a steam generator tube.

Plugs will be installed if sleeve installation is not successful or if there is tanacceptable degradation of a sleeve or sleeved steam generator tube. Standard steam generator tube plugs may be used to take a sleeved tube out of service.

1-1

d 1.2 IIACKGROUND The operation of Pressurized Water Reactor (Pwr0 m.

n eenerators has in some instances, resulted in localized corrosive attack on the inside (prunary side) or outside (secondary side) of the steam generator tubing. This corrosive attack results in a reduction in steam generator tube wall thickness. Steam generator tubing has been designed with considerable margin between the actual wall thickness and the wall thickness required to meet stmetural requirements. Thus it has not been necessary to take corrective action unless stuctural limits were being approached, llistorically, the corrective action taken when steam generator tube wall degradation has been severe has been to install plugs at the inlet and outlet of the steam generator tube when the reduction in wall thickness reached a calculated value referred to as a plugging criteria. Eddy current (ET) examination has been used to measure :. team generator tubing degradation and the tube plugging criteria accounts for ET measuremem uncertainty.

Installation of steam generator tube plugs removes the heat transfer surface of the l

plugged tube from service and leads to a reduction in the primary coolant flow rate available for core coollag, installation of welded and/or welded and hard rolled steam generator sleeves does not significantly affect the heat transfer removal capability of the tube being sleeved and a large number of sleeves can be installed without significantly affecting primary flow ran 1.3 ACRONYMS i

Table 1-1 (along with Table 5-1) contains a list of the acronyms used throughout this report.

1-2

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TABLEl-1 P

ACRONYMS USEl) IN REPORI

+ PolNT: + Point "

i ATS: Above the Tubesheet EFPil: Effective Full Power llours EPPY: Effective Full Power Years ET: Eddy Current Testing ETZ: Expansion / Roll Transition Zone LOF: Lack of Fusion PWIIT: Post Weld lleat Treatment TS: Tube Support UT: Ultrasonic Testing VT: Visual Testing 1-3

2.

SUMMARY

AND CONCLUSIONS The sleeve dimensions, materials and joints were designed to the applicable ash 1E Boller and Pressure Vessel Code. An extensive analysis and test program was undertaken to prove the adequacy of both the welded and welded hard rolled sleeve.

This program determined the effect of normal operating and postulated accident conditions on the sleeve tube assembly, as well as the adequacy of the assembly to perform its intended function. The proposed sleeving provides for a substitution in kind for a portion of a steam generator tube. The proposed change has no significant effect on the configuration of the plant, and the change does not affect the way in which the plant is operated. Design criteria were established prior to performir.g the analysis and test program which, if met, would prove that these sleeve types are an acceptable repair technique. These criteria conformed to the stress limits and margins of safety of Section 111 of the ash 1E B&PV Code. The safety factors of 3 for normal operating conditions and 1.5 for accident conditions were applied. Based upon the results of the analytical and test programs described in this report these sleeve types fulfill their intended function as leak tight structural members and meet or exceed all the established design criteria.

Evaluation of the sleeved tubes indicates no detrimental effects on the sleeve-tube l

assembly resulting from reactor system flow, coolant chemistries, or thermal and pressure conditions. Structural analyses of the sleeve tube assembly, using the l

demonstrated margins of safety, have established its integrity under normal and a:cident conditions. The structural analyses have been performed for sleeves which span the tube to a maximum length of [

] inches, sleeves which span a tube support or free span length of tube with a length of(

) inches and a combination of the sleeve types. The structural analyses performed are applicable to shorter tubesheet and tube support sleeves. The analyses for the different sleeve types and lengths are given in Section 8.

Mechanical testing using ash 1E code stress allowables has been performed to support the analyses. Corrosion tests of typical sleeve tube assemblies have been completed and reveal no evidence of sleeve or tube corrosion considered detrimental under anticipated service conditions.

Based upon the testing and analyses performed, the proposed sleeves do not result in a significant increase in the probability of occurrence or consequence of an accident previously evaluated, create the possibility for a new or different kind of accident, or result in a significant reduction in a margin of safety.

Welding development has been performed on clean tubing, dirty tubing which has been taken from pot boiler tests and contaminated tubing taken from a number of steam generators. ABB CE installed their first welded sleeves in a demonstration program at 2-1

Ringhals Unit 2 in May 104. Allli Cli's sleeving history is shown in Table 21. The success rate for all Installed sleeves is 98%. Since 1985, no sleeve which has been accepted based on NDIi has been removed from service due to service induced degradation.

Inspection methods have been qualified capable of detecting installation or inservice flaws consistent with the calculated minimum sleeve wall or weld thickness and an appropriate growth rate for the expected flaw type.

If a steam generator tube which has been sleeved is found to require plugging to remove it from service, a standard steam generator tube plug can be installed. No discussion or evaluation of the standard tubt plug is provided as part of this document.

In conclusion, steam generator tube repair by installation of any of Ae two types of sleeves described herein is established as an acceptable method.

I 2-2 4

TABLE 21 1

INSTAI l_ATIONS.DF ABB-CE WEJ2ED SLl! EYES i

INSTALLEl)

PLANT DATE OUANTITY TYPE

• Kewaunce 5/97 428 WTS 4

Zion 2 10/96 226 WTS KRSKO 6/96 273 TS 188 bTZ j

Hyron1 4/96 3527 ETZ Prairic Island 1 2/96 253 WTS ANO2 10/95 711 ETZ Zion 1 10/95 911 WTS Zion 2 1/95 162 WTS I

i Zion I 11/93 61 WTS i

j KRSKO 6/93 160 ETZ l

14 TS i

Ginna 4/93 51 WTS i

Zion 2 12/92 172 WTS Prairie Island 1 11/92 158 WTS Ginna 4/92 175 W7S 63 Curved WTS Zion 1 4/92 124 WTS l

Kewaunec 3/92 16 Curved WTS 4

j Ringhals 3 7/91 46 ETZ 22 TS Ginna 4/90 192 WTS 48 Cun'ed WTS Zion 2 4/90 82 WTS Prairie Island 1 1/90 63 WTS Zion 1 9/89 445 WTS 2-3

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TABl.E 21 (Continued) 4 -

INSTALL ATIONS OF AllB-CE WFI DED SI EFVES 4

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INSTAL 1 rn PLANT DATE QUANTITY TYPE 1

Ginna 4/89 395 WTS 1

j 107 Curved WTS l-Prairic Island 1 9/88 74 WTS Ringhals 2 5/87 571 WTS Prairie Island 1 4/87 27 WTS T

Ginna 2/87 105 WTS 1

{

Zion 1 10!R6 128 WTS j:

Ringhals 2

$/86 599 WTS j

Ginna 2/86 36 WTS i

Ringhals 2 5/85 59 WTS i

Ringhals 2

$/84 18 WTS y

\\

• Straight sleeves unless otherwise noted I

WTS - Welded Tubesheet TS - Tube Support ETZ Expansion Transition Zone l

2-4

4CCEPTANCE CRITERIA The objectives of installing sleeves in steam generator tubes are twofold. The sleeve trust maintain structural integrity of the steam generator tube daring normal operati't3 and postulated accident conditions. Additionally, the sleeve must prevent leakage in the event of a through-wall defect in the steam generator tube. Numerous tests and analyses were performed to demonstrate the capability of the sleeves to perform these functions under normal operating and postulated accident conditions.

Operating conditions used to bound the CE steam generators are def'med as:

(Pressure and temperature differences were conddered in determining bounding conditions)

Primary Side:

61l'F (operating) 2250 psig (operating)

(Ilot Side)

Secondary Side:

506'F (100% load) 815 psig (100% load)

Operating conditions used to bound the W steam generators are defined as:

(Pressure and temperature differences were considered in determining bounding conditions)

Frimary Side:

620 F (operating) 2250 psig (operating)

(Hot Side)

Secondary Side:

526 W M4 load) 815 psig (100% load)

Tsole 3-1 provides a sunmry of the criteria established for sleeving in order to demonstrate the acceptability of the sleeving techniques. Justification for each of the criterion is provided. Results indicatino the minimum level with which the sleeves sur-passed the criteria are tabulated. The r ;ction of this report describing tests or analyses which verify the characteristics for a 1, articular criterion is referenced in the table.

3-1

i TABLE 31 4

REPAIR SLEEVING CRITERIA Criterion Justification Results Section e

1.

Sleeve is leak tight Leadage between Welded joint is leak tight-4.0 i

prhnary and secondary and is checked using U.T.,

i side is prevented.

E.T. and/or V.T.

1 Rolled joint is leak tight by monitoring torque.

2.

Sleeve-tube assembly Sleeve tube assembly Structural margins 8.0 functional integrity must meets applicable ASME maintained for all be maintained.

Code requirements.

conditions.

3.

Axial load cycle without Bounds cycle loading No failure of weld or rolled 7.0 weld joint or rolled joint from normal operating joint. No damage to sleeve failure.

and transient cycling, or tube.

4.

Pressurization of annulus Prevention of sleeve Assembly collapse at 4500 7.0 between shme and tube failure for through wall psig.

does no. ed?. apt. sleeve at defect in tube wall.

1500 psig.

5.

Pressurize sleeve (without Factor of safety of three No assembly burst at up to 7.0 tube) to 4800 psig without for N.O. conditions.

6500 psig, bursting.

6.

Exposure of sleeve-tube Sleeve-tube assembly No detectable indication of 6.0 assembly to various required to function sleeve or joint corrosion or primary and secondary under coolant aggravated tube corrosion.

chemistries without loss chemistries of functionalintegrity.

7.

Non-destructive Periodic examination of ECT technique developed 5.0 examination of tube and tubes and sleeves that exceeds EPRI sleeve to levels of required to verify guidelines and Appendix H detectability required to structural adequacy requirements, show structural adequacy.

8.

Welded sleeve installation Sleeve repair should not System flow rate and heat 10.0 does not significantly reduce power removal transfer capability are not affect system flow rate or capability of reactor or significantly affected.

heat transfer capability of steam generator below the steam generator, rated value.

3-2 4,

4.

DESIGN DESCRIPTION OF SLEEVES AND INSTALLATION EQUIPMENT 4.1 SLEEVE DESIGN DESCRIPTION There are two (2) types of sleeves which may be installed in various combinations within a steam generator tube. These sleeves are shown in Figures 4-1, and 4-2. Each sleeve type has a nominal outside diameter of[

] inches and a nominal wall thickness of [

] inches. The sleeve material is thermally treated Alloy 690.

Each of the sleeve types include a chamfer at both ends to prevent hang-up of equipment used to install the sleeve and to facilitate the inspection of the steam generator tube and sleeve.

The first type of sleeve, shown in Figure 4-1, spans the expansion transition or roll transition at the top of the tubesheet. This Expansion / Roll Transition Zone (ETZ) sleeve is up to [

] inches long and includes a [

]

The second type of sleeve, shown in Figure 4-2, spans a tube support or egg crate support plate. This Tube Support (TS) sleeve is [

] inches in length. The sleeve spans a support plate elevation or can be used on a free span section of the tube.

4.2 SLEEVE MATERIAL SELECTION The thermally treated Alloy 690 tubing, from which the sleeves are fabricated, is procured to the requirements of the ASME Boiler and Pressure Vessel Code, Section 11 SB-163, Code Case N-20. Additional requirements are applied including a limit on Carbon content of 0.015 - 0.025% and a minimum annealing temperature of 1940 F (1060 C) for a minimum of two minutes. The thermal treatment is specified at 1300 F (704'C) for a minimum of five hours to impart greater corrosion resistance in potential faulted secondary side environments. The enhanced corrosion resistance is achieved in the thermal treatment by insuring the presence of grain boundary carbides and by reducing the residual stress level in the tubing.

The principal selection criterion for the sleeve material was its resistance to stress corrosion cracking (SCC) in primary and caustic faulted secondary PWR environments.

ABB-CE's justification for selection of this material and condition is based on the data contained in Reference 4.7.1.

4-1

4.3 SLEEVE-TUBE ASSEMBLY The installed sleeves are shown in Figures 4-3 and 4-4. The Expansion Transion Zone (ETZ)- sleeve spans the expansion / roll transition zone at the top of the tubesheet, if defects exist at a tube support or egg crate support plate, as well as, at the top of the tubesheet, an ETZ sleeve and a Tube Support (TS) sleeve may be used.

- The ETZ sleeve, shown in Figure 4 3, is [

] inches in length or shorter, The bottom of the sleeve is located near the neutral axis of the tubesheet. [

]

[

]

The TS sleeve shown in Figure 4-4 is [ ] inches in length, it is approximately centered at a support plate. [

l

[.

]

4-2

e l

__When it is considered to be of benefit (based on steam generator primary and i

secondary side conditons), a post weld heat treatment of the sleeve weld will be added to the sleeve installation process. After the sleeve has been welded into the tube, the weld joint is heated in the range of [

] As described in Reference 4.7.5, this time and temperature combination is sufficient to reduce the level of residual stress in Alloy 600 while minimizing detrimental effects such as grain growth or sensitization. This treatment is simihr to that utilized in some operating units to heat treat the tight radius U bends.

Qualification of the sleeve welding process is in accordance with the procedure described in Appendix A.

4.4 PLUGGING OF A DEFECTIVE SLEEVED TUBE If a sleeve or sleeved tube is found to have an unrepairable defect, the tube can be taken out of service with standard steam generator tube plugs installed at both ends of the tube using approved methods.

4.5 SLEEVE INSTALLATION PROCESS AND EQUIPMENT The equipment used for remote installation of sleeves in a steam generator is made up of the following basic systems. These systems are:

1. Remote Controlled Manipulator unemuuhult amusueuu 4-3

These systems, when used together, allow installation of the sleeves without personnel entering the steam generator. In this wny, personnel exposure to radiation is held to a minimum.

The tooling and methods described in the fol!owing sections represent the present technology for leak tight sleeve installation. As technological advances are made in sleeve installation, the new tooling and/or processes may be utilized after they have been laboratory-verified to provide improved sleeve installation methods.

4.5.1 Remote Controlled Maninulator The remote controlled manipulator (Figure 4-5) serves as a transport vehicle for inspection or repair equipment inside a steam generator primary head.

The manipulator consists of two major components; the manipulator leg and manipulator arm. The manipulator leg is installed between the tube sheet and bottom of the primary head and provides axial (vertical) movement of the arm. The manipulator arm is divided into the head arm, probe arm and a swivel arm. Each arm is moved independently with encoder position controlled electric motors. The swivel arm allows motion for tool alignment in both square pitch and triangular pitch tube arrays.

Computer control of the manipulator allows the operator to move sleeving tools from outside the manway and accurately position them against the tube sheet.

4.5.2 Tool Delivery Eauinment The purpose of the tool delivery equipment is to support and urtically position the various tools required for the sleeving operation and to provide controlled rotathn to some of the tools. Two different delivery systems may be used for the tool delivery.

[

]

The probe driver is a modified Zetec probe pusher or equivalent unit located outside the manway of the steam generator. A flexible conduit extending from the probe driver to an adaptor on the manipulator arm provides the guide path for the tools. The guide path adaptor is attached to the end of the manipulator arm by a dovetail fittin?

and manual lock. The drive wheels of the probe driver deliver the tools to the required elevations within the tube. Where positioning is critical, a hardstop attached to the tool shaft locates the tool relative to the steam generator tube end.

The tool delivery system for controlled tool rotation consists of two major components;

[

], Figure 4-6. The tool mounting plate is attached to the end of the manipulator arm by a dovetail fitting and manual lock. One or two sets of pneumatically operated fingers are used to draw-up and lock the tool mounting plate to the tube sheet. Proper alignment of the tool mounting plate to the 4-4

tube sheet is assured through the actuation of three switches against the tube sheet. A spring loaded, air pressure release, quick change mount is provided on the face of the tool mounting platform for quick mounting of the probe pusher or the rolling tool elevator.

The probe pusher attaches to the tool mounting platform with the quick change mount.

The probe pusher includes two double sets of drive wheels and two idler wheels. The drive wheels are powered by electric motors to insert and remove the various sleeving tools and the sleeve into the steam generator tube, Vertical positioning of the tools is accomplished by hardstops and/or verified by visual means. Controlled rotation of the weld and non-destructive examination (NDE) tools is provided by an electric motor which rotates the probe pusher relative to the tool mounting platfonn.

4.5.3 Tube Brushing-Cleaning Equinment 4.5.4 Tube Rolling Eauinment 7

4-5

4.5.5 Slecye Exnansion Equinment 4.5,6 Slet ? Welding Equinment guum 4-6

4.5.7 Nondesituctive ExaminatioD Three types of nondestructive examination equipment are used during the sleeving process. They are as follows: eddy current test (ET) equipment, ultrasonic test (UT) equipment (Figure 4-11) and visual test (VT) equipment (Figure 412).

The ET inspection will be performed using the most recently developed eddy current probes and techniques for sleeving inspection. The eddy current probe presently being used is the new advanced + point rotating probe. Future probe designs may be used after suitable qualification demonstration has been performed. The ET fixture, with conduit, is used on the manipulator arm to position the probe.

Ultrasonic testing using an immersion technique with demineralized water as a couplant is used to inspect the tube to sleeve weld. A one-quarter inch diameter focusing transducer is positioned in the weld area and rotated by the probe pusher to scan the weld. A digital imaging system is used to acquire and store the inspection data.

Visual inspection of the steam generator tube to sleeve weld is accomplished with the use of a boroscope or micro camera system delivered and rotated by the probe pusher, Inspection data is stored on video tape.

s 4.5.8 Post-Weld Heat Treatment Equipment 4

i wm 4.5.9 Sleeve Rolling Eauinment The sleeve rolling equipment is used to expand the lower end of the ETZ into contact with the steam generator tube within the tubesheet, forming a strong leak tight joint.

The rolling tool is mounted on the manipulator and positioned within the tube by a hard st0p on the roll tool shaft seating against the tube sheet. The rolling tool includes a dovetail attachment for quick mounting on the manipulator. The rolling tool mounted 4-7

on the manipulator, [

] may be used in the central tubesheet region or in the periphery.

The rolling equipment consists of the air motor, tube expander, torque read-out, strip chart recorder and a torque calibration unit. The torque read-out and settings of the rolling tool are verified on the torque calibration unit prior to rolling of the sleeves.

The rolling tool is located by a hardstop on the tool shaft. The hardstop positions the upper end of the tube expander within the portion of the sleeve which was hydraulically expanded during sleeve installation. The approximately 1-1/4 inch long roll is located at the nickel and metal oxide bands on the lower end of the ETZ sleeve.

The sleeve is expanded to a torque which has been demonstrated by testing to provide a leak tight joint. A record of the rolling tool torque is made for further evaluation of the rolling process on the individual sleeves. A rolled joint which fails to meet the acceptance criteria may be re-rolled.

4.6 ALARA CONSIDERATIONS The steam generator repair operation is designed to minimize personnel exposure during installation of sleeves. The manipulator is installed from the manway without entering the steam generator. It is operated remotely from a control station outside the containment building. The positioning accuracy of the manipulator is such that it can be remotely positioned without having to install templates in the steam generator.

The tool delivery equipment is designed so that the dovetail fitting quickly attaches to the manipulator. The probe pusher is designed to quickly engage the individual sleeving tools. The tools are simple in design and all sleeving operations are performed remotely using tools held by the manipulator. Each tool can be changed at the manway in 10-15 seconds. A tool operation is performed on several sleeves rather than performing each tool operation on the same sleeve before proceeding to the next sleeve. Thii reduces the number of tool changes which are required. Spare tools are provided so that tool repair at the manway is not required. If tool repair is necessary, the tool is removed and sleeve operation continues using a spare tool. The tool may or may not be repaired during the outage but repair is performed in an area which does not have significant radiation.

Air, water and electrical supply lines for the tooling are designed and maintained so that they do not become entangled during operation. This minimizes personnel exposure outside the steam generator All equipment is operated from outside the containment. The welding power source and programmer is stationed about a hundred feet from the steam generator in a low radiation area.

Lead lined manway shield doors, both primary side and secondary (ventilation) side, are also employed to reduce radiation exposure.

4-8

. _ _. _ ~

J

4.7 REFERENCES

TO SECTION 4.0 i

i 4.7.1 Alloy 690 for Steam Generator Tubing Annlications, EPRI Report NP-6997 October 1990.

4.7.2 Sedricks, A. J., Schultz, J. W., and Cordovi, M. A., "Inconel Alloy 690 - A New Corrosion Resistant Material", Janan Society of Corrosion Engineering, 28, 2 (1979).

4.7.3 Airey, G. P., " Optimization of Metallurgical Variables to Improve the Stress Corrosion Resistance ofInconel 600", Electric Power Research Institute

]-

Research Program RPl708-1 (1982).

l 4.7.4 Airey, G. P., Vala, A. R., and Aspden, R. G., "A Stress Corrosion Cracking Evaluation ofInconel 690 for Steam Generator Tubing Applications", Nuclear Technology, 55, (November, 1981) 436.-

4.7.5 Hunt, E.S. and Gorman, J.A., Specifications for In-Situ Stress j

Relief of PWR Steam Generator Tube U-hends and Roll Transition, EPRI Report NP-4364-LD, Electric Power Research Institute, Palo Alto, CA, December 1985.

4.7.6 Krupowicz, J. J., Scott, D. B., and Fink, G. C., " Corrosion Performance of j

Alternate Steam Generator Materials and Designs Vol. 2: Post Test 1

Examinations of a Seawater Faulted Alternative Materials Model Steam Generator," EPRI-NP-3044, July 1983.

1 4.7.7 G. Santarini et al, Recent Corrosion Results - Alloy 690, EPRI Alloy 690 Workshop, New Orleans, LA, April 12-14, 1989, l

l 4-9 i

1 t

=

FIGURE 4-1 EXPANSION /ROl1 TRANSITION ZONE SLEEVE 4-10

4 Y

FIGURE 4-2 TUBE SUPPORT SLEEVE 4-11

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FIGURE 4-3 EXPANSION /ROl1 TRANSITION ZONE SI FEVE INSTAI I A'M 4-12

--,,n N

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FIGURE 4-4 TUBE SUPPORT SI FEVE INSTAI I ATION 4-13

h FIGURE 4 5 MANIPULATOR AND TOOL DEIIVERY SYSTEM 4-14

1 1

4 FIGURE 4-6 TOOL DELIVERY EOUIPMENT 4-15

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d FIGURE 4-7 TUBE CIPANING EQUIPMENT 4-16

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FIGURE 4-8 SLEEVE EXPANSION EOUIPMENT 4-17

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upmene FIGURE 4-9 SiFEVE WELDING HEAD ASSEMBLY 4-18

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i FIGURE 4-10 SI EEVE WELDING HEAD POWER SUPPLY UNIT 4-19

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FIGURE 4-11 ULTRASONIC TEST EOUIPMENT

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6 FIGURE 4-12 VISUAL TEST EQUIPMENT 4-21

4 FIGURE 4-13 POST WEID HEAT TREAT EOUIPMENT 4-22

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FIGURE 4-14 SLEEVE ROI T ING EQUIPMENT 4-23

5.

SLEEVE EXAMINATION PROGRAh!

During the installation process, the sleeves are examined using a combination of visual testing (VT), ultrasonic testing (UT) and eddy current testing (ET) at different stages of the installation process. The general process is described in the flow charts presented in Figures 51 and 5-2, which are described below.

After the description of the inspection process, the individual inspection methods will be described in a&litional detail.

After completion of the brush cleaning step, the first inspection is a VT process on tubes to be sleeved to confirm adequate cleaning to proceed with the welding process.

Parent tube cleanliness has been identi0ed as a critical feature of the overall welding process. A VT after cleaning is performed with a miniature remote camera inserted into the tube up to the elevation where the welding will be performed. The VT inspectors are trained using images of examples of acceptable and inadequate cleaning.

In simplest terms, the cleanliness requirement is the presence of " bright, shiny metal" in the region of the tube where welding will take place. If adequate cleaning is not confirmed by the remote VT, then the cleaning process is repeated until a suitable cleanliness is achieved. The extent of this inspection program is presently 100% of tubes to be sleeved. At such time that process control is demonstrated to assure cleaning efficiency, a sampling program may be used.

1 Upon confirmation of cleaning, the sleeve is inserted, expanded and welded. The next inspection is performed on the ATS weld by UT to confirm a leak tight Sond has been achieved by the welding process. The weld height is not measured by the UT method, but rather is controlled by the welding process qualification. A confirmation of 360 degrees of weld bond is the acceptance criteria for the UT inspection. if a lack of fusion (LOF) through the weld height is detected, then the sleeve may be identified for rewelding or plugged. After a reweld, the UT is repeated to confirm a leak tight weld. An acceptable UT result is required for any ATS weld left in service.

Prior to the UT inspection, an optional VT-1 inspection of the ATS weld may be performed, but is not required. The VT-1, as defined in ASME Section XI, is suitable for detection of incomplete welds, blow holes and weld rplatter geometric irregularities in the weld. Experience has shown that the UT and ET inspections are capable of detecting these conditions, so the VT is primarily useful t > help resolve uncertainties in surface conditions detected by either the UT or ET inspections. If a 5-1

I VT-1 inspection is performed and a blow hole or other potentially deleterious condition (with the exception of an incomplete weld) is detected, then a noncomforma ice report (NCR) must be generated. Blow holes identified as within the pressure boundary portion of the weld must be repaired. Blow holes not within the pressure boundary portion of the weld are identifad for additional evaluation by the ET and UT inspections.

The final inspection is performed on all installed sleeves using the ET method with a

+ point probe. If post weld heat treatment is performed, this inspect;on mus:

• rm formed after the heat treatment due to the possibility of additional signals ~..on.

permeability variations caused by the heat treatment process. The entire length of the pressure boundary, including the pressure boundary portion of the parent tube behind the sleeve is inspected with the ET method, The pressure boundary portion of the sleeve tube assembly is shown in Reference 5.4.3. The details of the ET inspection are described in Section 5.2 and Figure 5-2 with the associated definitions in Table 5-1.

The sleeve to tube weld joints ate qualified by process control as described in Appendix A, Checks are made to ensure that the welds meet these design requirements. The welding current and voltage are recorded as the weld head rotates inside the sleeve. The recordings are examir.ed after the welding sequence has been completed to verify that the essential parameters given in Reference 1 to Appendix A are met.

These descriptions of inspection techniques and tooling represent the current state-of-the-art practices. As new technology becomes available, advanced techniques may be substituted after a suitable qualification program has demonstrated equivalent or superior performance.

5.1 UL1 RASONIC INSPECTION 5.1.1 Summary and conclusions An ultrasonic inspection is performed on each sleeve to tube ATS weld to confirm a leak tight fusion. The test is performed using an ultrasonic crystal with a resonant frequency of [

] MHz (physical construction of the probe will reduce the effective output frequency to [

] MHz, typically. Actual output frequency is documented in the transducer certification package required by procedure.) The mechanical drive device performs a scan of the weld in 2 degrec increments around 360 degrees with axial step increments of [

] inches; the sun path extends from above the weld so that the sleeve backwall is detected to below the weld until the backwall of the sleeve is detected. The inspection is demonstrated to detect a milled notch representing a weld lack of fusion (LOF) region of [

] inch or greater. The ultrasonic signal is 5-2

digitized and stored in order to provide a permanent record of the individual A scans (lower presentation on Figure 5-4), which are used to display plan view C scans (upper presentation on Figure 5-4) of the weld as well as cross sectional views in the axial direction (B' scans) and cross sectional views (B scans). For each individual sleeve inspection, a calibration confirmation is available by monitoring the response to the sleeve back wall either above or below the weld zone.

5.1.2 Ultrasonic Evaluation The basis of the UT inspection is the detection of a reDective surface at the sleeve to tube interface to detect a condition indicative of a lack of fusion. Sound is transmitted from the sleeve inner surface through the weld to the tube outer surface. Although the reDection from the tube outer surface is typically discernible in the recorded data, this is a sufficient, but not necessary indication of fusion Geometric distortions in the weld region may preclude detection of this tube back wall as a consistent indicator of weld Tusion.

In the data acquisition phase, a C scan is displayed for the operator with a [

] for monitoring reflections from the sleeve / tube interface. During analysis, both circumferential and axial cross sectional views of the ul:nsonic reDectors are reviewed for evaluation of each weld. Detection of a [

] reDection is an indication of a complete weld.

In the absence of this signal, axial and circumferential cross sections (B and B' scans) data reviews are conducted. Locally, reflectors are compared to 20% of the sleeve backwall signal amplitude for determination of a local LOF. Using the B' scan axial cross section, a LOF condition through the weld height is discernible.

Using a combination of laboratory samples and removed tubes (Prairie Island, February,1996),

unbonds as narrow as 10 degrees are detectable using this B scan analysis techniques, as reported in References 5.4.1 and 5;4.2. Sample outputs from the UT results for an acceptable weld and unacceptable LOF condition are provided in Figures 5-3 (acceptable) and 5-4 (rejectable).

5.1.3 Test Eauinment The test equipment for the ultrasonic inspection comprises the following:

1, IntraSpect Ultrasonic Imaging System

2. Sleeve Weld UT Inspection Probe,15 MHz,0.250" diameter crystal, sized for sleeve ID, as depicted in Figure 5-5 5-3

3. Couplant supply system, integral with the probe and driver system

4. Position device for rotational and translational motion, include encoder feedb:.ek for cael, axis

5. Calibration standard with machined notches for initial set up, as depicted in Figure 5 6.

5.2 EDTW CUllRENT INSPECTION 5.2.1 llackground For the initial installation of sleeves, each sleeve will be inspected for a baseline and for acceptance. Over the years, the eddy current probe technology has evolved with ever increasing sensitivity in the probe response. Early sleeving programs used a cross wound bobbin coil design, which was later replaced by the I coil design and ultimately by the plus point probe design. The current practice uses the plus point probe design with the option of adopting future probe designs after suitable qualification demonstration b Sec'1 performed. The description below discusses the most recent plus point probc. : sign, which was extensively qualified for sleeve inspections in a program that exceeded the requirements of the EPRI Steam Generator inspection Guidelines, Appendix 11 in effect at this writing, as described in reference 5.4.3. This qualification used a detection threshold of 40% degradation of the sleeve wall thickness rather than the 60% allowed by Appendix 11 to add conservatism to the process.

The B; method is used to inspect the entire sleeve region pressure boundary which has four distinct regions.

1) the sleeve between the upper weld and lower joint (either roll or weld, dependbg on sleeve type)

2) the pressure boundary region of the steam generator tube behind the sleeve

3) the steam generator tube below the lower rolled joint for an ETZ sleeve

4) the unsleeved portion of the steam generator tube The first three regions are the subject of this discussion, the fourth region is handled as part of the normal tube inspection using the prevailing methods. If post weld heat treating is performed on the weld zone, the ET inspection is performed after the heat treatment.

l 54 l

7

5.2.2 Ehts_ Point Probe Qualification.Siudy The plus point ET technique was extensively qualified for each of the regions identified above using laboratory samples with EDM notches and laboratory produced weld imperfections. The details of the inspection samples and results for the weld zone indications are provided in references 5.4.1 and 5.4.2 and the Appendix 11 qaal10 cation report is provided in reference 5.4.3. The Appendix 11 qualincation report provides the details for both the acquisition (ACTS) and analysis (ANTS) of the it spection data.

Site specine analysis guidelines have been developed and analysts are trained and tested on the specines of the technique. In summary, the plus point technique was demonstrated to be able to detect relevant Haw mechanisms 40% throughwall and l

greater in each of the regions identified above.

Farticular attention was paid to the ATS weld region of the sleeve. The detailed process for the initial installation inspection is shown in the Dow chart in Figure 5 2 with the companion list of acronyms in Table 5-1.

For the subsequent inservice inspections, reviews of previous inspection results may be used in lieu of the VT and UT reviews mentioned in the now chart. Either the standard + point probe or the magnetically biased style may be used for the inspectier Experience has shown that one of the most common interfering signal sources in the weld region is caused by local permeability variations, which are greatly reduced by the partial magnetic saturation provided by the magnetically blued probe.

l The ET indications are separated into two broad categories, surface and subsurface.

Surface indications are caused by minor weld sag which produces a signal classified as GEO for geometric. Local irregularities in the weld surface are classified as weld surface indications (WSI). In extreme cases, the WSI source could he a blow hole in the weld. Additional VT reviews are used to evaluate surface related indications prior to acceptance. With the aid of the VT data, WS! signals are resolved as blow holes outside or within the pressure bountry ponion of the weld (BilA or BilH) or nondeleterious surface irregularities (WSS), if no surface condition is observed, then the signal is considered as a subsurface weld zone indication (WZl) and evaluated accordingly. For blow holes, the location relative to the pressure boundary is determined using a combination of the VT and UT results. Accordingly, the BilA (blow hole outside pressure boundary portion of the weld) condition is acceptable for service while the BilB (blow hole within the pressure boundary portion of the weld) is not.

The WZI signals may be caused by oxide inclusions in the weld or a partial void caused by a gas pocket during the welding process. Metallographic work, as reported in reference 5.4.1, has shown that these conditions occur at either the upper or lower edge 55

of the ATS weld on the sleeve outer surface. The oxide inclusion condition is generally precluded by proper cleaning, which is verified using VT before installing the sleeve.

Minor volds may occur in a small percentage of welds even with proper cleaning, but generally are very shallow. No attempt is made to distinguish inclusions from volds, nor is there an attempt to measure depth or circumferential extent for these conditions.

The only acceptance criteria is based on the location relative to the pressure boundary with indications outside the pressure boundary portion of the weld (WZA) acceptable for service and indications within the pressure boundary portion of the weld (WZB) not acceptable for service. The ability to determine the true location of indications relative to the pressure boundmy portion of the weld was demonstrated in the Appendix 11 qualification study and is reported in references 5.4.2 and 5.4.3. It is Allll CE's l

position that sleeved tubes will be plugged upon detection of indications in the pressure l

boundary region of the sleeve. The methodology for this detection is shown in the flow l

charts in Tables 51 and 5-2.

Various other anomalous conditions may be reported by the ET analyst that would trigger a nonconformance report (NCR) and additional evaluation.

The other area of particular interest is the expansion transition zone above the weld, llere the parent tube constitutes the pressure boundary. The ability to detect 40%

through wall flaws was demonstrated using EDM notches and is detailed in reference 5.4.3.

5.3 VISUAL INSPECTION 5.3.1 Summary niid conclusions There are two visual inspections associated with the sleeving process. The first inspection is performed after the brush cleaning process for the weld region. Tubes are inspected for cleanliness prior to sleeve installation. The second, optional inspection is performed after completion of the ATS weld and is conducted as a VT-1 inspection per Section XI of the ASME Code. The VT 1 inspection is performed when needed to resolve surface indications identified by the ET or UT inspections. The VT-1 inspection is also performed for tewelds.

The VT is performed remotely by taeans of a miniature CCD camera inserted into the tube with the results recorded on video tape Visual aids are provided for the inspectors for evaluation of cleaning and weld quality. A training tape with examples of weld irregularities is provided and reviewed by the VT-1 inspectors. Conditions of interest include blow holes, incomplete welds, splatter, pits and burn through.

5-6

5.3.2 Graning inspecilon After the cleaning operation, the parent tube in the region where the weld will be made is inspected for adequacy of cleaning. Approximately a two inch long zone is cleaned and inspected. The acceptance criteria is bright, shiny metal to assure that there is no remaining oxide on the tube surface that could affect the weld quality by producing inclusions. This process verification step is identified in the site specific traveller. The extent of this inspection program is presently 10% of tubes to be sleeved. At such time that process control is demonstrated to assute cleaning efficiency, a sampling program may be used.

5.3.3 Weld Examination l

The primary inspection methods for ATS weld and sleeve acceptance are the UT and ET methods described above. An additional VT 1 inspection of the weld is optional, unless required by the site procedure for specific situations, such as repair welds. The VT-1 is also used as a supplemental technique to aid in the analysis of surface l

conditions reported in either the UT or ET results.

The CCD camera and right angle viewing mirror is inserted into the sleeve. The camera system is checked using a 1/32" black line on an 18% neutral gray card. Also, a sleeve sample with a 0.020" diameter through hole is used to scale the image. The VT-1 results are recorded on video tape for permanent storage.

5.4 REFERENCES

5.4.1 ABB CENO CEN-628-P Rev Ol P, " Verification of the Structural Integrity of the ABB CENO Steam Generator Welded Sleeve, March,1996 (PROPRIETARY) 5.4.2 ABB CENO 96-3 9038T Rev 01, " POD Assessment for NDE of Sleeves",

June 14,1996 5.4.3 ABB CENO 96 OSW-003, "EPRI Steam Generator Examination Guidelines Appendix 11 Qualification for Eddy Current Plus Point Probe Examination of ABB CENO Welded Sleeves", April 27,1996 (PROPRIETARY) 5-7

TABLE 5-1 ACRONYMS USED IN ET ANALYSIS BilA: Blow llole Outside Pressure Houndary l

BilB: Blow llole Within Pressure Boundary GEO: Geometric signal LOF: Lack Of Fusion NCR: Nonconformance Report NDD: No Detectable Degradation PID: Positive ID retest RMB: Retest with Magnetically I"ased probe UT: Ultrasonic Test VT.1: Visual Test, Type 1 per ASME Code,Section XI VT: Visual Test WEE: Weld at Edge of Expansion W OE: Weld Outside Expansion region WSI: Weld Surface Indication WSS: Weld Surface Signal WZA: Weld Zone indication Outside Pressure Boundary WZB: Weld Zone indication Within Pressure Boundary WZl: Weld Zone Indication subsurface or indeterminant 5-8 F

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6.

SI FFVE.TWECORROSON TEST PilOGRAM AHH-CE has conducted a number of bench and autoclave tests to evaluate the corrosion i

resistance of the welded sleeve joint. Of particular interest is the effect of the mechanical expansion / weld residual stresses and the condition of the weld and weld heat affected zone. Tests have been performed on welded joints with and without a i

i post weld heat treatment. An outline of these tests is shown in Table 61. [

}

6.1

SUMMARY

AND CONCLUSIONS i

l N

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6.2 TEST DESCRIPTION AND RESULTS 6.2.1 Primary Side Tests N

6-1

TAllLE 61 SIIIAM GENERATOR TUlli; St EEVE CORRoslON TESTS EmptBumt eEEEdhEEE 6-2 v

6.2.1.1 Pure Water Stress Corrosion Cracking _ Tests i

l l

6.2.1.2 Above the Tubesheet (ATS) Weld Capsule Tests

.e 6-3 i

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6.2.1.3 TSP Sleeve Weld Capsule Tests e>u 6-4 s

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l 6.2.1.4 Summary Primary Coolant Corrosion Performance M

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6.2.2 Secondary _ Side _Ints 6.2.2.1 Modified lluey Tests l

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l 6.2.2.2 Capsule Tests M

6-7

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- TABLE 6-3 SECONDARY SIDE STEAM GENERATOR TUBE SI FFVE CAPSUI F TESTS l

ENVIRONMENT EXPOSURE TIME

-RFRULTS 6.2.2.3 Sodium Hydroxide Fault Autoclave Tests 6-8

l l

l 6.2.2.4 Summary - Secondary Coolant Corrosion Performance N

6-9

v.,

~

6.3 REFERENCES

FOR SECTION 6.0 6.3.1 Statistical Analysis of Steam Generator Tube Decradall00, EPRI Report NP-7493, September 1991.

l-6.3.2 Summary Report, Combustion Engineering Steam Generator Tube Sleeve l

Residual Stress Evaluation, TR-MCC-153, November 1989.

6.3.3

1. L. W. Wilson and R. G. Aspden, " Caustic Stress Corrosion Cracking of Iron Nickel Chromium Alloys." Stress Corrosion cracking and Ilydrogen Embrittlement ofIron Base Alloys, NACE,llouston, Texas, pp 1189 1204, 1977.

6.3.4 A. J. Sedriks, S. Floreen, and A. R. McIlrce, "The Effect of Nickel Content on the Stress Corrosion Resinance of Fe-Cr Ni in an Elevated Temperature Caustic Environment". Corrosion,Vol. 32, No. 4, pp 157158, April 1976.

6.3.5 F. W. Pement, I. L. W. Wilson and R. G. Aspden, " Stress Corrosion Cracking Studies ofliigh Nickel Austenitic APoys in Several Illgh Temperature Aqueous Solutions " hiaterintsperformance, Vol.19, pp 43 49, April 1980.

6.3.6 P. Berge and J. R. Donati,

• Materials Requhements for Pressurized Water Reactor Steam Generator Tubing

• NuclearTechnnlogy, Vol, $$, pp 88-104, October 1981.

6.3.7 G. P. Airey, A. R. Vala and R. G. Aspden, "A Stress Corrosion Cracking Evaluation of inconel 690 for Steam Generator Tubing Applications." Nuclear Technnlogy, Vol. 55, pp 436-448, November 1981.

6.3.8 J. R. Crum and R. C. Scarberry, " Corrosion Testing of Inconel Alloy 690 for PWR Steam Generators." Journal of Materinic for Energy Systems, Vol,4, No. 3, pp 125130, December 1982.

6-10

l l

FIGURE 6-1 PURE WATER CORROSION TEST SPEr *g 6-11

j FIGURE 6-2 ATS WEl_D CAPSUI E TEST EPECIMEN 6-12

FIGURE 6-3 TSP WFID CAPSUL _E TEST SPECIMEN 6-13

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FIGURE 6-4 CAUSTIC CORROSION AUTOCLAVE TEST EPECIMEN 6-14

7.

hiECilANICAL TESTS OF St lCEVICD STEAM GENEl(NE0lLTUllES 7.1-

SUMMARY

AND CONCLUSIONS 7.2 CONDITIONS TESTED 7.3 WELDED SLEEVE TEST PARAMETERS AND RESULTS 7.3.1 Arial Pull Tests k.nemst 7-1

7.3.2 Collanse Testing

~

7-2 7,

7.3.3 Durst Testing 7.3.4 Load Cycling Tests

.me 7-3

N

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TABLE 7-1 SJ FRVE-TUBE ASSEhiBLY hiECIIANICAL TESTING RESULTS*

COhiPONENT AND TEST RESULT (hiAX1hiUhi) RESULT (hilNihiUhi)

Welded Joint Axial Load Capability Upward Direction Downward Direction Rolled Joint Axial Load Capability-No slippage l

Welded Joint Cyclic Loading Rolled Joint Cyclic Loading Sleeve Burst Pressure Sleeve Collapse

• A minimum of three tests of each type were performed.

7-5

8,0 SIRUCTURAL MALYSIS OF SI EEVE. TUBE ASSEMlllJ This analysis establishes the stmetural adequacy of the sleeve-tube assembly.

The methodology used is in accordance with the ASME Boiler and Pressure Vessel Code, Section 111. The work was performed in accordance with 10CFR50 Appendix B and other applicable U.S. Nuclear Regulatory Commission requirements.

8.1

SUMMARY

AND CONCLUSIONS i

Based on the analytical evaluation contained in this section and the mechanical test data contained in Section 7.0, it is concluded that both the Expansion / rolled Transition Zone (ETZ) and Tube Support Plate (TS) sleeves described in this document, meet all the requirements stipulated in Section 8.0 with substantial additional margins. In performing the analytical evaluation on the tube sleeves, the operating and design conditions for all of the ABB-CE as well as the Westinghoure coerating plants with 3/4 inch Inconel 600 tubes are considered (Reference 8.2).

8.1.1 Design Sizing in accordance with ASME Code practice, the desip requirements for tubing are covered by i

the specifications for the steam generator " vessel". The appropriate formula for calculating the minimum required tube or sleeve thickness is found in Paragraph ND 3324.1, tentative pressure thickness for cylindrical shells (Reference 8.1). The following calculation uses this formula for the tube sleeve material which is Alloy 690 material with a specified minimum yield of 40.0 ksi.

}

Where t = Min, required wall thickness, in.

P = Design Tubesheet differential pressure, ksi (max. value for plants, Ref. 8.2)

R = Inside Radius of sleeve, in. (maximum value for plants considered)

S, = Design Stress Intensity, S.I. @ 650*F maximum design (per Reference 8.16) 8.1.2 Dftailed Annlysis Summary When properly installed and welded within specified tolerances, the ETZ sleeve and its upper weld and lower rolled joint, and the TS sleeve and its two primary welds possess considerable margin against pull-out for all loading which can be postulated from operating, emergency, test, and faulted conditions.

8-1

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TABLE S-1

SUMMARY

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• - The allowables listed in Table 8-1 are in accordance with the ASME Code (Ret'. 8.1 and 8.16) s 4

8-4

FORh1ULAS FOR GENERAL h!Eh!BRANE STRESSES SUhth!ARIZED IN TABLE 8-1 (Note: All SI equations below are a derivation of the formula in Par NB 3324.1 of Ref. 8.1.)

1. GENERAL PRIhi. h1EhfBRANE STRESS (DESIGN TUBESilEET DELTA PRESSURE) 1 1

l I

2IMAIN STEAM I INE BREAK FOR ABB-CE PLANTS i

l 3-FFFDWATER LINE BREAx FOR WESTINGHOUSE PLANTS 4IPRIMARY PIPE BREAK (LOCA) w 8-5

TABLE 8-2

SUMMARY

OF ROI I ED JOINT DESIGN. ANALYSIS AND TEST RESULTS W

i mm.

M 8-6

8.2 LOADINGS CONSIDERED In this section a number of potential failure modes are examined to determine the relative safety margins for selected events. Failure loads are calculated based on minimum dimensions and compared with mechanical testing results from Section 7.0. Both calculated and measured loads are compared with the maximum postulated loads.

8.2.1 Upner Tube Weld Pullout Load 1

Assuming the parent tube is totally severed, the minimum load required to shear the upper tube weld is calculated.

The force required to pull the expanded sleeve through the unexpanded tube is conservatively neglected.

In the event of a main steam line break (MSLB) for an ABB-CE plant, the secondary pressure would drop in a short time interval. Without rapid operator action, subsequent to the dryout of the faulted steam generator, continued Emergency Core Cooling System (ECCS) flow, combined with the heatup of the RCS from decay heat, a gradual repressurization of the RCS will result in a maximum value of 2520 psi (Reference 8.9). Postulating a main steam line break (MSLB) accident, the maximum available load would be In the event of a feedwater line break (FWLB) accident for a Westinghouse plant, the value of 2850 psi (Reference 8.4) is used. The maximum pullout load would be:

m h

8-7

8.2.2 Lower Sleeve Rolled Section Pushout Load 4

Assuming the parent tube is totally severed, the minimum load required to tupture the lower rolled section is calculated. The minimum measured test value for the pushout load is 2000 lbs., see Section 7.

Postulating a loss of primary coolant accident (LOCA) during hot standby condition (0% Power), the maximum available load would be:

Note that the LOCA pipe break accident is not controlling for this joint. See Section 8.4.6.

8.2.3 Weld Fatigue Since the factors of safety are quite high for loadings due to primary stress, the failure mechanism of greatest interest is the fatigue failure mode considering the variable axial loading of the sleeve during normal operating transients.

In Section 8.6.1, fatigue evaluations of the upper weld, which join the sleeve to the tube will be made. it is first necessary to determine the effects that tube lock-up within the tubesheet and tube supports have on the axial loads in the sleeve during normal operation.

This subject is addressed in Section 8.4.

8.3 EVALUATION FOR ALLOWABLE SLEEVE WALL DEGRADATION USING REGULATORY GUIDE 1.121 4

NRC Regulatory Guide 1.121 (Reference 8.3) requires that a minimum acceptable tube (or sleeve) wall thickness be established to provide a basis for leaving a degraded tube in service. For partial thru-wall attack from any source, the requirements fall into two categories, (a) normal operation safety margins, and (b) considerations related to postulated pipe rupture accidents.

8.3.1 Normal Oneration Safety Margins It is the general intent of these requirements to maintain the same factors of safety in evaluating degraded tubes as those which were contained in the original construction code, ASME Boiler and Pressure Vessel Code,Section III (Reference 8.1).

For Inconel Alloy 600 and 690 tube or sleeve material the controlling safety margin is:

" Tubes with partial thru-wall cracks, wastage, or combinations of these should have a factor of safety against failure by bursting under normal operating conditions of not less than 3 at any tube location".

8-8

From Reference 8.2, the normal operating conditions for the " worst" case envelopment of steam generators from both the ABB-CE and Westinghouse plants are:

ABB-CE -

Westinghouse Primary Pressure P :

2250 psi 2250 psi l

g Secondary Pressure P,c:

815 psi 877 psi Differential Pressure AP = Pg - P.,:

1435 psi 1373 psi Average Pressure P,,., = 0.5 (Pg + P,c):

1533 psi 1564 psi Assuming the parent tube is totally severed, the sleeve is required to carry the pressure loading.

The following terms are used in this evaluation.

R = sleeve nominal inside radius Sy

= minimum required yield strength (per U.S. NRC Reg. Guide 1.121, Ref. 8.3)

Sym, = minimum yield strength of sleeve (Sy = 35.2 ksi min, at 650 F, Ref. 8.16) k m

8-9

8.3.2 Postninted Pine knoture Accidents NRC Regulatory Guide 1.121 requires the following:

"The margin of safety against tube failure under postulated accidents, such as a LOCA, steam line break, or feedwater line break concurrent with the safe shutdown earthquake (SSE), should be consistent with the margin of safety determined by the stress limits specified in NB-3225 of Section Ill of the ASME Boiler and Pressure Vessel Code".

The above referenced ASME code paragraph deals with " faulted conditions", where for an elastic analysis ofInconel 690 sleeves, a general membrane stress of 0.7 S, = 0.7(80.0) = SLO ksi is allowed. In conjunction with the NRC Regulatory Guide 1.121, the following accidents are postulated:

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8.3.3 Minimum Weld lleight Requirement N

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EFFECTS OF TUBE LOCK-UP ON SLEEVE LOADING Objective: Conservatively determine the maximum axial loads on the sleeve (tension and -

compression) during normal operation.

1 i

l t

l l-8,4,1 Sleeved Tube in " Worst" Case ABR-CE Plant. Free at Egg Crate Supoort 8-13

1 1

8.4.2 Sleeved Tube in " Worst" Case Westinghouse Plant. Free at Tube Support N

N 8-14

8.4.3 Sleeved Tube in " Worst" Case ABB-CE Plant. Lock-up at First Ecc Crate Support I

8.4.4 Sleeved Tube in " Worst" Case Westinchouse Plant. Lock-up at First Sunnort 6

8-15

TABLE 8-3A -

26 INCH SIFFVE AXIAL MEMBER PHYSICAL PROPERTIFS FOR " WORST" CASE ABB-CE PLANT NOTE: ' Nominal Dimensions for sleeve from Reference 8.10.

2 a, ami E for Inconel 690 from Ref. 8.13, Part D, Tables TM4, TE4 (same or more conservative than Ref. 8.12).

' Nominal Dimensions for tubes from Reference 8.15.

1. e, ami E for inconel 600 from Reference 8.13, Part D, Tables TM4, TE4.

5 a, for Carbon Moly Steel from Reference 8.13, Part D, Table TE-1.

8-16

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TABLE 8-3B 26 INCH SI FFVE AXIAL MEMBER PHYSICAL PROPERTIES FOR " WORST" CASE WESTINGIIOUSE PLANT NOTE:.' Nominal Dimensions for sleeve from Reference 8.10.

2 a, aml E for Inconel 690 from Ref. 8.13 Part D. Tables TM-4, TE-4 (same or more conservative than Ref. 8.12).

' Nominal Dimensions for tubes from Ref:rence 8.14.

• a, ami E for Inconel 600 from Reference 8.13, Part D Tables TM-4. TE-4.

5 for Carbon Moly Steel from Reference 8.13, Part D. Table TE-1.

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AXIAL LOADS IN SIFFVE WITII TURE LOCKED INTO TUBE SUPPORT FOR " WORST

• CASE WESTINGIIOUSE PLANT

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• NOTE: Due to small variation E and u, value for normal operation,100% power are used.

i 8-21 f

8.4.5 Effect of Tube Prestress Prior to Sleeving e

I 8.4.6 Imwer Sleeve Rolled Section Pushout Due to Restrained Thermal Exnancion N

h 8-22

8.5 SLEEVED TUBE VIBRATION CONSIDERATIONS The vibration behavior is reviewed since the installation of a sleeve in a tube could affect the dynamic response characteristics of the tube.

8.5.1 Effects ofIncrewd Stiffacss Stiffness and mass have opposing iruluences on tube vibration. While increased stiffness tends to raise the tube natural frequency, increased mass terxis to lower it. ABB-CE's vibrational testing (Reference 8.6) demonstrated among other things, that a solid rod of the same O.D. as a tube will vibrate at nearly the same frequency. However, the displacements l

for the stiffer rod will be significantly less.

In addition, if any contact is made between the tube and sleeve along their length, the increased damping will absorb more energy. The damping would have a significant effect onthe amplitude of vibration. In light of this damping effect and the other above mentioned effects resulting from a sleeve inside a tube, the vibration performance of the tube / sleeve assembly is superior over the original tube.

8.5.2 Effect of Severed Tube 6

M 8-23

N N

8-24

- 8.5.3 Seismic Evaluation The_ natural frequency of a sleeved tube for the span between the tubesheet and the first tube support for the " worst" case situation is:

2 f, = (15.4/2n1 ) x (Elg/W/l)"5 = 11LO HZ, (Reference 8.5) where:

f, = natural frequency, HZ i

l = span length = 47.75 in. (maximum value in Reference 8.2) -

E = 28.78 x 10' psi (minimum value for Inconel 600 tube at 573.3 F)

I = Tube Moment ofInertia = 0.0066 in.'

W = Tube Weight + Weight of Primary Water in Tube & Sleeve + Sleeve Weight +

Weight of Secondary Water Displaced W = 1.542 + 0.374 + 0.279 + 0.581 = 2.775 lb.

2 g = 386 in/sec The natural frequency is based on a healthy tube span with an installed sleeve. Vibration test results of sleeved tubes (See Section 8.5.2) concluded that tube sleeves have negligible effect on the vibration characteristics of the tubes. Test results indicate a natural frequency for a completely severed tube somewhat below the healthy tube frequency, but above the seismic cuteff frequency of 33 HZ. Hence, the seismic evaluation is performed for the static equivalent load above 33 HZ.

The seismic load for a " worst" case situation, which more than envelopes the seismic curves in Reference 8.2 for loading above 33 HZ, is:

OBE = 2.25 g In the span between the tubesheet and support the OBE seismic load is:

woes = (1.0 + 2.25) W/l = 0.189 lb./in.

For the fixed - pinned model the maximum moment is:

2 Moss = 1/8 w l = 53.8 in.-lb.

ost 8-25

4 Considering the sleeve cross section:

i l

It is concluded that a seismic event produces a small stress in the tube sleeve.

1 i

1 8-26

l 8.6 STRUCTURAL ANALYSIS FOR NORMAL OPERATION A static clastic n.alysis of the sleeved tube assembly was performed according to the requirements stipulated in Nil 3220 Section 111 of the ASME Code Section. Section 8.6.1 describes the methods used to analyze the upper tube weld.

8.6.1 Eatigue_Eriduation of Upner sleeve / Tube _ weld 8-27 4

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8-28 i,-w.,

TAllLE 8 6 I

UI'PER SLIII!VEylilD. TRANSIENT 1CONSIDERiii) FOR AN Ailli-CE l'LANT

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8-29

TAllLE 8 7 IJfPER Sl_FIIVE WEl_D. TRANSIENTS FOR A WESTINGilOUSE PLANT N

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8.7 REFERENCES

FOR SECTION 8.0 i

8.1 ASME Boiler and Pressure Vessel Code, Section til for Nuclear Power Plant Compcnents, 1989 edition.

8.2 ABB/CE Letter Report No, CSE-96 ll6, " Tube Sleeve llistory Data for 3/4 inch Steam Generator Tubes", May 07,1996.

8.3 U.S. NRC Regulatory Guide 1.121. " Bases for Plugging Degraded PWR Steam Generator Tubes".

8.4 ABB/CE License Report CEN-624 P, Rev. 00, " Carolina Power & Light Shearon liarris Steam Generator Tube Repair Using Leak Tight Sleeves", July 1995.

8.5 " Mechanical Vibrations",4th Edition, by J.P. Ilartog, McGraw liill Book Co., New Yo,k, New York, pg. 432.

8.6 " Vibration in Nuclear lleat Exchangers Due to Liquid and Two Phase Flow," By W.J. lleilker and R.Q. Vincent, Joun.al of Engineering for Power. Vol.103, Pages 358 366, April 1981 (REF %-015).

8.7 "ANSYS" Finite Element Computer Code Rev 5.1,1994, by Swanson Analysis Sys., Inc.

8.8 EPRI NP 1479, "Effect of Out of Plane Denting Loads on the Structural Integrity of Steam Generator Internals," Contractor: Combustion Engineering, August 1980, 8.9 ABB/CE License Repon CEN-613 NP, Rev. 01, " Arizona Public Service Co. Palo-Verde Steam Generator Tube Repair Using leak Tight Sleeves", January 1995.

8.10 ABB/CE Drawing No. D-SGNS-222-001. Rev. 02, "RTZ Sleeve for 3/4" Diameter Steam Generator Tubes".

8.11 ABB/CE Drawing No. D-SGNS 222-002, Rev. N "RTZ Sleeve Installation".

8.12 inconel 690, iluntington Alloys, Inc., iluntington, W. Virginia.

8.13 ASME Boiler and Pressure Vessel Code Section 11, Materials,1995 edition.

8.14 Westinghouse Steam Generator Standard Information Package, Jan. N,1982 (REF %-002).

8.15 ABB/CE Drawing No. E 234-622, Rev.1, " Tube Details for SONGS 11 Steam Generator" 8.16 ASME Boiler and Pressure Vessel Code Case N 20-3, "SB 163 Nickel-Chromium-tron Tubing (Alloys 6CX) and 690)... at Specified Minimum Yield Strength of 40.0 ksi.... Section 111 Division 1, Class 1", November 30,1988.

8.17 ABB/CE P.eport No. TR ESE 178, Rev.1, " Palisades Steam Generator Tube / Sleeve Vibration Tests", Oct>ber 05,1977 (REF-96@3).

8 34

l l

FIGURE 8-1 WFI DED SLEEVE / TUBE ASSEMBLY 8-35

l FIGURE 8 2 SYSTEM SCIIEMATIC FOR " WORST

• CASE ABB-CE PLANT 8 36

)

l l

l FIGURE 8 3 SYSTEM SCllEMATIC FDR " WORST" CASE WESTINGIIOUSE PLANT 8 37

l ene impe M

STIFFNESS MODFI OF Si nRVE AND LOWER TUBE 8-38

FIGURE 8 5 i

STIFFNESS MODEI OF UPPER TUBE AND SURROUNDING TUBES 8-39 1

{

l I

l l

FIGURE 8-6 FINITE El FMENT MODEL OF UPPER TUBE WFI D 840

i l

APPENDIX 8A l

FATIGUE EVALUATION OF UPPER SLEEVE / TUBE WELD i

8A-1 l

INTRODUCrKIN The analysis presented in this appendix is discussed in detail in Section 8.6.1 of this Report. The I

results from the two (2) finite element models considered are presented in this Appendix. The model geometry is shown in Figure 8 6 of the report. The only difference in the two models is the weld height and the number of elements. The 80 mil weld height model is based on the design geometry minimum dimension. The 20 mil matel is based on the minimum required axial weld length for operating and accident conditions. All stresses and usage factors for both configurations l

are satisfactory when compared to allowables.

l GENERAL DISCUSSlON The Finite Element Method (FEM) was incorporated in this analysis, using the ANSYS Computer Code (Reference 8.7). Figure 8-6 depicts the FEM model of the upper tube weld for both the Allll CE and Westinghouse operating plants with inconel 600 tubes. A tube thickness of.043 inches is conservatively used in the analysis. This will encompass the.048 inch tube design.

The lower end of the tube was ascumed to be locked near the secondary side surface of the tubesheet. From Section 8.4, it was found that the sleeve develops higher compressive loadings if the tube is free to slide through the first support. Therefore, slid;ng at the tube to-support interface was conservatively assumed. The FEM model consists of 2 D isoparametric elements with an axisymmetric option. The ANSYS input and output data are included in Attachment 1.

The axial loads are conservatively detennined from a thermal interaction for a 30 inch sleeve length using the equations in Section 8.4. These axial loads are applied to the bottom of the sleeve finite element model. The Allll-CE operating and transient conditions are used because they result in the highest temperature differences and highest axial loads. The transients were selected on the basis of the worst case combinations as explained in Section 8.6.1. The stresses resulting from the axial load cases are combined with the 100'7e steady state pressure case stresses. These combined stresses are combined with the thennal case stresses resulting from the radial thennal expansion for the transients considered.

I A stress concentration factor of 4 is conservatively applied to the linearized membrane plus bending stresses for the axial, radial and shear stress components. The concentration factor is applied at the sleeve outside surface located below the weld, the top and bottom of the weld, and to the inside surface of the tube location above the weld.

The minimum required axial length of weld of.023 inches was detennined in Section 8.3.3. A fatigue analysis was perfonned using a conservative weld height of.02 inches. The finite element model used for the.08 inch weld design was modified by refining the element mesh as shown in Appendix 8A. For simplification purposes, the pressure stresses and stresses due to the radial thermal expansion were conservatively excluded. These pressure and thennal stresses result in tensile stresses which relieve the compressive stresses resulting from the axial loads.

l The results of the analyses consist of the nodal stresses at the critical section, range of stress evaluation and the calculation of the fatigue usage factor, i

i 8A 2

~

I FIGURE 8A.]

ODE AND STRRRS CITI' IDENTIFICATION 8A-3

TAllLE 8A-1 A SIRESS RIISULTS 100% STEADY STATII SA-4

TAllLl! 8A ll!

SIRESS ItFMULTS 159 STEADY STATE 8A 5 l

m 1

TAllLE 8A-lC SI1ESS HIMUI TS 09 STEADY STATE W

8A-6

TAllLE 8A lD S13fiSS RiiMULTS FliliDWATER CYCLING M

M 8A 7

TABLl! SA 2A RANGE 01: STRIISS AT WORST LOCATION SeE l

W SA 8

TAllLE 8A 211 EATlGUli IIVALUATION AT WORST 1.OCATION t

gass 8A-9

s_,g 4

..-%.-.4

.u4_-,..%

J

.4,

.=-., -,

-.E.i

.m

---4

._.m a

N

'l 1

M FIGURE 8A 2 HQDE AND STRPRS CUT IDENTIFICATION FOR 20 MIL WFI D 8A-10

TABLE 8A 3A SIFFRS RFSULTS 1007e STEADY STATE LO21.Wdd) 8A 11

TAllLE 8A-3Il STRESS RESULTS 15c4 STEADY STATE ( 02" Weld) h m

emu 8A-12

\\.

TABLE 8A 3C SHESS.1ESULTS 09 STEADY STATE (.02" Weld) l 8A 13

TABLE 8A-3D SIFRSS RESULTS FEEDWATER CYCLING 002" Weld) 8A 14 i

l

TABLE 8A4a RANGE OF SIRFSS AT WORSTlt M AflONS (.02" Weld) 8A-15

I TABLE 8A-4B FATIGUE EVALUATJON AT WORST LOCATIONS 002" WehD l

t-8A-16

i TABLE 8A-4B (Cont'd)

FATIGUE EVALUATION AT WORST LOCATIONS (.02" Weld) i a

8A-17 i

APPENDIX 811 tulle SLEEVE HISTORY DATA hee O

O 8B-1

A ED ED

1. %EDED asu sac.n ecvEm Inter-Office Correscondence To:

W. R. Gahwslier May 07,1996 Soue:ast Nu:!nr Service Cent:r c::

D. P. Siska CSE-96 ll6 / Page 1 of 4 D. G. Stepnick T. M. Taylor

SUBJECT:

TUBE SLEEVE IIISTORY DATA FOR 3/4 INC11 STEAM GENERATOR 'IVBES

REFERENCES:

(1) CEN 601 P Rev. 0-P Lice:tse Repon, " Arbm Nuc!:ar O= Unit 2 Stam Generator Tube Repair Usmg Leak Tight Sleeves", June 1992.

(2) CR-9417-CSE92-1119-0 Repon.

• Evaluation of an ABB/CE Tube Simt h Application in Louisiana Power & Ught Sea ~. Gen:rators Waerford Unit 3* Nov:=ter 1992.

(3) CR-N17 CSEN-11194 Repon.

• Evaluation of an ABB/CE Tube Sle v: for Application in Maix Yanle: Steam Generato's*, September 194.

r (4) CR-N17-CSE93-1123-1 Report, " Evaluation of an ABB/CE Tube Sle:ve for Application in APS - Palo Verde Units 1,2, & 3 Seam Generators". January 1995.

(5) CR-W19-CSE95-1119-0 R:pon. " Evaluation of an ABB/CE Tube Stem for Appli:ation in B G.&I. Calvert Cliffs Seam Gen:rators*, September 1995.

(6) CENC-1272 & 1298 Reports. *Amlytical Reports & Soucem California Edison San Onofr:

Units 2 & 3 Steam Generators *, Sepember 1976 and Sepe=ber 1977.

(7) CEN-368 P Rev. 0-P License Repon, " Florida Power & Light Co. St. Luci: Units 1 & 2 Stum I

l Ge=rator Tube Repair Using Luk Tight Sle:ves*, February 1983.

i (8) CEN-337-P Rev. 0-P License Repon 'V. C. Summ:r Seam Ge=rator Tube Repair Using Leak Tight Slems", August 1986.

(9) CEN 3SS-P Rev. 0-P License Report, Houston Power & Ught Soud Tens Steam Generator Tube Repair Using le.ak Tight Sle:ves", April 1990.

)

(10) CEN-401-P R:v. 0 P License Report, Ringhals 3 & 4 Steam Ge=rator Tube Repair Using Leak Tight Sleeves". October 1990.

(1l) CEN-600-P Rev.1 P Ucense Report *ASCO 1 & 2 Stam Ge=rator Tube Repair Using Leak Tight Sleeves *, June 1992.

(12) CR-9417-CSE93-1115-0 Report.

• Evaluation of an ABB/CE Tube Slem for Application in Krsko Steam Ge=rators*, June 1993.

(13) CR-9451-CSE95-11%0 Repon,

• Evaluation of an ABB/CE Tube Sleeve for Application in Commonwn!!h Edison Byron & Braidwood Units 1 & 2 Stam Ge=rators*, April 1995.

(14) CR-9451-CSE95-1111-0 Report.

• Evaluation of an ABB/CE TtWe Slem for Application in Carolina Power & Light Shearon Harns Stum Ge=rators*, July 1995.

Southeast Nuclear Service Cent:r (SNSC) reviewed the past tube sleeve reports for 3/4 inch steam g:cerator tubes.

Ref:rences 1 through 14 contain be Section 8 struemral analysis as pan of the lic:nse reports, A review was also made of the other 3/4 in:h seam generator tubes, primarily, the Westinghouse D2/D3/D4 Series steam generators to see if their parameters would produe: a

• worst

• case situation great:r than those plants reviewed in References 1 through.14. Table 1 on pages 3 and 4 contain de n:::ssary paramet:rs from the founeen references to develop a

• worst

• case envelopment simation for further structural analysis of 3/4 inch tube sl::ves. These

• worst" case it:ms for ' operating

• plants with inco=1600 steam gen:rator tubes are not:d in Tabl: I wid an ast: risk (*).

CSE-96-ll6 / Page 2 of 4 For a " single

• Westinghouse Plant study of all D2/D3/D4 steam generators with inconel 600 mbes (including those plants not in the fourteen references), the ASCO 1 & 2 Plants (whose steam generators are being replaced with ones containing Alloy 800 tubes) had the largest ail load on the tube sleeve. However, the next largest axial load on the tube sleive is the CP&L Shearon Hams Plant which still has Inconel 600 tubes in the steam generator. His axial load calculation is 939 lb. which is mainly due to the maxtmum difference between the pnmary and secondary temperatures used in the structural analysis (i.e. 93.5'F).

For a ' single

• ABB/CE Plant study of all the steam generators with inconel 600 tubes (including those plants not in the fourteen references), the Waterford 3 and SONGS Plants will have the largest axial load on the tube sleeve, primarily, due to the maximum difference between the prunary and secondary temperatures in the peripheral tubes for tbc structural analysis being 105'F.

l Sincerely, G. $ 2 p

B. A. Be!!

1

- VERIFICATION STATUS: COMPLETE ne Safety-Related design information crmrnined in this document has been wrtfied to be correct by means of Design Review using Checklist in QP-3.4 of QPM 101.

Name _,[ 11 M.

Signamre

1) Idv Date r M Independem Revnwtr L/

U BAB:bab m

4

• 4

+

m.

l TAHLE 1:

INCONEL 690 tulle SLEEVE FOlt 3/4" DIAMETElt 'IUllE CSE-96-116 / Page 3 of 4 PARAMETER A NO.2'"

Waterli>rd 3*

Maine YanLee'"

APS HG1E SONGS *'

FP11.St. laie Palo Verde'*

Calvest Clifff I & 2"'-

Tufc Sleeve lenEfft/Reput issue Date 42.25"/6-92 43.0"/11-92 15.5 /9-94 40 0 /l-95 300*/995 not issted 400*/283 Design Tulesleet DilTerential 2250

• 2250*

2250*

2250*

2250*

2250

• 2250*

Pressure (psi) Use Max.

Primary Pressure @ 100% Power (psi) 2250*

2250

• 2250*

2250

• 2250

• 2250

• 2250

• Use Max.

Secondary Press. @ 100% Power (psi) 900 900 815

• 1070 850 900 815' i Use Min.

- Primary Temp. @ 100% Power (*F) 6II 611 601.8 621.2 601 61I ml Secorxlary Temp.@ 100% Power (*F) 532 (511 ")

532 (506 ")

520.3 (506**)

553 503""

$32 (506")

520 (500 ")

Prim.-Sec. Temp. @l00% Power (*F) 79 (100) 79 (105*)

81.5 (95.8) 68.2 101 79 (10$*)

84 (101)

Use Max. Di!Tererre Primary Temperature @ XX% SS OF) 554 554 542 573 543 554 547 (543 ")

(15%)

(15%)

(10%)

(15%)

(15%)

(15%)

(15%)

Secondary Temp. @ XX% SS (*F) 539 539 (527 ")

528 561 518 539 (527 ")

528 (518 ")

(15%)

(15%)

(10%)

(15%)

(15%)

(15%)

(IS%)

Prim-Sec. Temp @XX% SS (*F) 15 15 (27) 14 12 25

• 15 (27) 19 (25)

Use Max. Difference Prim. Temp. @ 0% SS (*F) Use Max.

544 544 532 564 532 544 532 Sec. Temp. @ 0% SS (*F) Use Max.

544 544 532 564 532 544 532 Span trngtfi tetween 'Ibtesleet & Ist 28.125 28.25 46.0 4735*

39.0 28.25 39 63/26.13 Suppwt (in.) Use MaxJMin.

Seismic Lead Use Max.

0.35 g 0.33 g 0.18 g 1.0 g 0.5 g 2.25 g

• 0.25 g (OHE)

(OllE)

(ODE)

(OIIE)

(OBE)

(OBE)

(ODE)

Tulesfret Thickness w/ Cladding (in.)

2135 2235 2031*

2335 21.44 2235 2135(112)

Use Min.

Secondary Pressure During IBCA 1100 1000 1000 1170 1000 1100 llxX)

Axial liiad fmm Refererre Repwt (ib.)

794 788 814 732 993 N/A 769

+. " Worst

• Case Envelopnent Use Waterford 3 & SONGS Data for werst case ABB/CE Plant study tisc CP&l.Slicaron llarris Data for worst case Westinclunne Plant stuity

" - Consideration for downconer/reedwater sulcooling (1) Referefre(1)

(2) Referefre(2)

(3) Refererre(3)

(4) Referente (4)

(5) Reference (5)

(6) Referette (6)

(7) Reference (7)

(16) Canisideration for graigderal tules

TAllLE 1:

INCONEL 690 tulle SI.EEVE FOlt 3/4" DIAMETElt tulle (cenit'<!)

CSE-%-116 / hge 4 of 4 PARAMlil ER V.C. Summe:**

IIP &L Soutfi Ringlials 3 & 4"'

ASCO l & 2""'

Krstd'*

Ilynm &

CP11.Strann D3 Texas *' E2 D3 D3 D4 Ilraidatuf

• D4

!!arris"* D4 Tule Sleeve lengtfi/Repint Isste Date 40.0 /8-86 40.0 14-90 43.0*/10 90 43.0 /5-92 17.5 /6-93 20.0*/4/95 200/79 I

Design Tutestrel Difrerent'al 1600 1600 1600 1600 1600 1600 16(X)

Pressure (psi) Use Mar.'

Primary Pressure @ 100% Power (psi) 2250

• 2250

• 2250*

2250

• 2250

• 2250

• 2250

• Use Max.

Seco x!ary Press. @ 100% Power (psi)

%4 1100 877 987 920 925

%4 Use Min.

PrimaryTemp. @ 100% Power (*F) 619 626 613 620 617 618 620 Sec. Temp." @ 100% Power (*F) 540 556 529 543 535 536 526.5 Prim.-Sec. Temp. @l00% Power (*F) 79 70 84 77 82 82 93.5 Use Max. Di!Tererte Primary Temperature @ XX% SS CF) 567 576 567 567 567 567 367 (15%)

(15%)

(15%)

(15%)

(15%)

(15%)

C5%)

Secondary Temp. @ XX% SS (*F) 556 566 556 556 556 556 548.5

, (15%)

(15%)

(15%)

(15%)

(15%)

(15%)

(15%)

Prim.Sce. Temp @XX% SS (*F) 11 10 II 11 1I 11 18.5 Use Max. Difference Prim. Temp. @ 0% SS (*F) Use Man.

557 567

• 557 557 557 557 557 Sec. Temp. @ 0% SS (*F) Use Max.

557 567

• 557 557 557 557 557 Feedwater Cycling (*F) 557/537 543/546 557/537 557/537 557/535 557/557 533/557 Span 12ngt!: trtween Tutesteet & Ist 27.25 9.0

• 27.85 27.85 36.0 36.0 36.25 Support (in.) Use MaxjMin.

Seismic land Use Max.

N/A N/A N/A N/A N/A 2.0 g (OllE) 1.5 g (OllE)

Tuleslicet 'Ihickness w/ Cladding (in.)

21.15 22.65 21.18 21.18 21.18 21.18 21.18 Use Min.

Secorxlary Pressure During IDCA 1072 1198

• 1092 1091 1091 1165 1170 Axial land from Reference Report (!b.)

754 815 80L1 1208 818 830 939 Use Waterford 3 & SONGS Data for worst case Allil/CE Plant sandy Use CP11. Sticanm llartis Data fix surst case Westingfiotr c Plant staly

• .

• Worst Case Envelopnent

" - Centsideration fin dow1:coner/feedwater suficenli"C

, 8) lieference (8)

(9) Iteference (9)

(10) Iteference (10)

(11) Reference (lI)

(12) Reference (12)

(

(13) Itefcrence (9)

(14) Rcfcscisce (14)

(15) Replaced wiili steani cencraines unnaining Incewwe 690 aimi Alloy Etx):ules

9, SLEEVE INSTALLATION VERIEICAI1ON 9.1

SUMMARY

AND CONCLUSIONS The ABB-CE welded sleeve installation process and sequence has been tested to ensure the installation of a sleeve which conforms to the design criteria described in Section 3.

During this testing, actual steam generator conditions, such as the innuence of tubes locked at tube supports, have been considered in assessing the acceptablity of the various processes and the sequence in which they are performed.

Actual sleeve operating history, as well as the qualification test program described within this report indicate that the ABB-CE eam generator tube sleeve is capable of performing as well as, if not longer than, the original tube in which it has been installed.

9.2 SLEEVE-TUBE INSTALLATION SEQUENCE 9.2.1 Expansion / Roll Transition Zone Sleeve with Rolled Lower Joint The ETZ Sleeve with the rolled lower joint is described in Section 4.3 and Figure 4-3.

Installation is accomplished using the processes described in Section 4.5 in the following sequence:

• Sequence may be performed interchangably 9-1

I 9.2.2 Inhe_ Support Steere The TS Sleeve is described in Section 4.3 and Figure 4-4. Installation is accomplished using the processes described in Section 4.5 in the following sequence:

• Sequence may be performed interchangably 9.3 WELD INTEGRITY Initiated in 1983, ADB Combustion Engineering has conducted a comprehensive development program to ensure weld joint integrity. Tube I.D. brushing tests, sleeve / tube expansion tests and weld parameter evaluation tests were all completed as part of the process verification.

9.3.1 Cleaning Oualificahon An additional test was conducted to determine whether the I.D. tube brushing would introduce noise interference on the bobbin coil eddy current test. A clean section of tubing was baseline tested to determine I.D. noise levels. The tubing was subsequently heat treated to produce an oxidation layer on the tube. One half of the tube section was then brushed to remove the oxide coating and the sample was retested with the bobbin coil. The results (Figure 9-1) show that the oxide does in fact generate a noise 9-2

component. Ilowever, after the tubing is brushed, the noise level returns to that of the baseline (pre-heat treat) data.

1 9.3.2 Expansion Oualification An extensive test program was performed to qualify the [ bladder expansion] tool and process, which provides a tight sleeve / tube fit up in preparation for welding. This program considered tubing with thick, thin and nominal walls as well as tubing with different heat treatments (yield strengths).

l 9.3.3 Weld Oualification e

1 9-3

s 9.3.4 Ultrasonic Testing Oualification Ultrasonic (U.T.) techniques are employed to confirm the presence of weld fusion into the tube. A test program was completed by ABB CE to qualify the Ultrasonic Examination of sleeve / tube upper welds. Fourteen sleeve / tube weld specimens were prepared for this qualification program. Each weld was ultrasonically inspected and

- then hydrostatically tested to confirm U.T. results. Test results indicate complete correlation between ultrasonic and hydrostatic testing.

9.3.5 - Post Weld Heat Treat Ouali(ication The tubing used in some steam generators has been shown to be very susceptible to the effects of Primary Water Stress Corrosion Cracking (PWSCC) - As a result, these utilities must minimize the residual stress induced in the steam generator tubing

- associated with any repair process. If sleeving is selected as the repair method, the-sleeve to tube weld joint as well as the weld heat affected zone and primary preseure

- boundary portion of the tube expansion requires annealing to minimize residual stresses. - {

].

m ese 9-4

9.3.5.11nstmmented Analysis oflaked Tubes A plot of the temperature profile and the axial load measured are shown in Figure 9-3.

The results of this test are shown in Table 9-3. Although no measurements were taken, no abrupt changes in the tube diameter were observed along the length of the tube. It was concluded that the deformation experienced by the tube would not be detrimental

- either to the installation process, i.e.. in preventing the tool from being removed, or to the long term performance of the sleeve / tube joint as described in Section 5.

A similar test was performed on a two by four array of.750 inch 0.D. x.042 inch wall tubes arranged in a square pitch and supported as shown in Figure 9-4. This configuration replicates the first three hot leg supports of a typical Westinghouse D3 Series generator while conservatively simulating aspects of a CE unit. In addition, this 9-5

configuration is conservative when compared to a Westinghouse Series 44/51 steam generator. Four of the tubes were locked at their support (but not the FDB) location by tack welding in four locations. The other four were free from the tubesheet to Support Plate No. 8. Two Tube Support (TS) sleeves and a tubesheet sleeve were installed in each tube as shown in the figure. The tubes were instmmented with strain gages to determine the strain in the outer fibers. During the heat treatment of each sleeve the strain in the tube was recorded. A load cell was used to determine the total load in the upper most section of tube. In the case of this mockup, the heat treatment commenced at the upper most weld and proceeded toward the tubesheet. Both sleeve welds (where applicable) were treated prior to any strain gage measurements. A typical temperature / time plot is shown in Figure 9-5. The results of the test are shown in Table 9 2. As would be expected, the more times the tube segments experiences the heat treat cycle the greater the residual stress. Examination of the tube surfaces in the vicinity of the welds indicated [

}.

l 9.3.6 Summary In summary, ABB-CE has conducted a comprehensive development and verification program to ensure weld integrity of its leak tight sleeves. Experience has shown that oxide layers as visually confirmed to exist on the steam generator secondary side do not affect weld parameters and the abrasive cleaning method described in the report is effective in preparing the tube for welding.

9-6

9.4 ROLLED JOINT INTEGRITY

\\

A development program was conducted to ensure the rolled joint of the ETZ sleeve I

was leak tight and capable of withstanding the design loads. The sleeves were rolled into mock ups consisting of steam generator tubes which had been rolled into blocks simulating the tube sheet. The sleeves were then tested to confirm the rolled joint was leak tight both before and after cyclic load testing, Tests of the rolled joint were also conducted where process parameters such as torque, tube diameter and roll location relative to the [

] were varied. A test matrix was used to verify the sleeve installation with sleeve rolling process parameter tolerances. The test program confirmed that the rolled joint integrity is acceptable within the allowable rolling process tolerances.

9.5 COMMERCIAL SLEEVE INSTALLATION ABB-CE's commercial sleeving experience is shown in Table 9-3. The success rate for all installed welded sleeves is 98%. Since 1985, no sleeve which has been accepted based on U.T. and V.T. has been removed from service due to service related degradation.

9.6 REFERENCES

FOR SECTION 9.0 9.6.1 Test Report on Steam Generator Tube Cleaning for Installation of Welded Sleeves, TR-MCM-126, 9.6.2 An Investigation of the Installation of Welded Sleeves in R.E. Ginna Tubing, TR-MSD-128, 9.6.3 Sleeving Centrifugal Wire Brush Development and Life Test Report, TR-ESE-705.

9.6.4 S.G. TSP /RTZ Sleeving-Tube I.D. Cleaning for 3/4 Inch O.D. X.042/.043 Wall Tubes, TR-ESE-860.

9.6.5 Steam Generator Sleeving - 3/4 inch Program, Bladder Expansion Pressure, TR-ESE-755, 9.6.6 Steam Generator Sleeving - 3/4 inch Program, Qualification of RTZ and TSP Sleeve Expansion Tools and Bladder Life Test, TR-ESE-809.

9.6.7 Ultrasonic Examination of 3/4 inch O.D. S.G. Tube to Sleeve Upper Welds, TR-400-001.

9-7

l 9.6.8 Quali0 cation of the Post Weld lleat Treatment Tool for Westinghouse "D" Series Steam Generators,00000-ESE-830.

9.6.9 Qualification of the Roll Transition Zone (RT2) Sleeve Rolled Joint,00000 ESE-

826, 9-8

TABLE 9-1 0.875" O.D. SLEEVED TUBE PWIIT DATA l

l M4 i

'unums m

4 4

9-9

TABLE 9-2 0.750" O.D. SLEEVED TUBE PWIIT DATA TUDES LOCICED AT ALL SUPPORTS l

i t

9-10

TABl.E 9 3 AUD CENO S/G SLEEVE OPERATING lilSTORY I

m 9-11

M meuraus FIGURE 91 POST HEAT TREAT - BRUSHED SECTION 9-12

u u un h M

I FIGURE 9-2 0.875" O.D. LOCKED TUBE TEST 9-13

Nd i

l f

FIGURE 9-3 0.875" O.D. LOCKED TUBE TEST TEMPERATURE AND AXIAL LOAD PROFILE 9-14

N N

FIGURE 9-4 0.750" O.D. LOCKED TUBE TEST 9-15

l FIGURE 9-5 0.750" O.D. TYPICAL TEMPERATURE PROFILES 9-16

10.0 EFFECT OF SLEEYlRG ON OPERATION Multiple plant specific analyses have been performed to detennine the effects of installation of varying lengths and combinations of ETZ and TS sleeves. Sleeve lengths and various combinations of installed sleeves were used to evaluate the effect of sleeving on the hydraulic characteristics and heat transfer capability of steam generators. Using the head and flow characteristics of.the pumps, in conjunction with the primary system l

hydraulic resistances, system flow rates have been calculated as a function of the l

number of sleeved tubes and the types of sleeves installed. Similarly, curves are generated from calculations that show the percent reduction in system flowrate as a function of ncwly plugged tubes (per steam generator). These curves are derived from plant specific information based on the following steam generator conditions.

Number Of Open Tubes Per Steam Generator Number Of Tubes Sleeved Primary System Flowrate Primary Coolant Temperature This information has been used to generate tables, such as Table 10-1, that provide hydraulic equivalency of plugs and installed sleeves, or the sleeve / plug ratio. Table 10-1 is provided as an approximation only and is based on assumed operating parameters and sleeve types for steam generators with 3/4 O.D. tubes. It must be assumed that some variations in the sleeve / plug ratio will occur from plant to plant based on operating parameters and steam generator conditions.

The overall resistance to heat transfer between the primary and secondary side of the t

steam generator consists of primary side film resistance, the resistance to heat transfer through the tube wall, and the secondary side film resistance. Since the primary side film resistance is only a fraction of the total resistance and the change in flow rate.is so small, the effect of this flow rate change on heat transfer is negligible.

When the sleeve is installed in the steam generator tube there is an annulus between the sleeve and tube except in the sleeve-tube weld regions. Hence, there is effectively little primary to secondary heat transfer in the region where the sleeve is installed. The loss in heat transfer area associated with sleeving is small when compared to the overall length of the tube.

In summary, installation of sleeves does not substantially affect the primary system flow rate or the heat transfer capability of the steam generators.

10-1

TABI E 10-1 TYPICAL St EEVE TO PLUG EOUIVALENCY RATIO CASE CONFIGURATIOS RATIO _(Sleeve / Plug)*

1 ETZ (1) 2 ETZ (1) + TS (1) 3 ETZ (1) + TS (2)

• This ratio should be considered approximate due to plant to plant variations.

10-2 g

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APPEND 1H PROCESS AND WEl_D OPERATOR OUAI IFICATIONS A.1 SI FFVE WFI DING AND SI FFVE WEI DER QUAI IFICATION Sleeve welding is qualified using an approved test procedure (Reference 1). The sleeving test procedure is in compliance with applicable sections of the ASME Code. Sleeve welders are qualified using test records in accordance with applicable sections of the ASME Code.

The test procedure specifies the requirements for performing the welds, the conditions (or changes) which require requalification, the method for examining the welded test assemblies and the requirements for qualifying the welding operators. Sleeve welding is qualified by performing six consecutive welds of each type which meet specified design requirements. Welders are qualified by performing two consecutive successful welds of each type.

A.2 REFERENCES TO APPENDIX A 1.

Welded Steam Generator Tube Sleeve Semi ' Automatic Gas Tungsten Arc Detailed Welding Procedure Qualification, Test Procedure 00000-MCM-050 A-1

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i ENCLOSURE 4 Allil/CE PROPRIETARY AND NON-PROPRIETARY TOPICAL REPORTS 96-OSW-003-P AND 96-OSW-003-NP "EPRI STEAM GENERATOR EXAMINATION GUIDELINES - APPENDIX 11 QUALIFICATION FOR EDDY CURRENT PLUS-POINT PROBE EXAMINATION OF AllI1/CE WELDED SLEEVES."

SAN ONOFRE UNITS 2 AND 3 f

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