ML20135F044
| ML20135F044 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/06/1997 |
| From: | BALTIMORE GAS & ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20135F027 | List: |
| References | |
| NUDOCS 9703110145 | |
| Download: ML20135F044 (14) | |
Text
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ATTACHMENT 1 1
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UNIT 1 MARKED-UP TECHNICAL SPECIFICATION PAGES l l
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, Revised Pages:
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3/4 4-14 I
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9703110145 970306 PDR ADOCK 05000317 p PDR Baltimore Gas & Electric Company Docket Nos. 50-317 and 50-318 March 6,1997
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3/4.4 REACTOR C00LANT SYSTEM l
SURVEILLANCE REQUIREMENTS (Continued)
- 10. Tube Repair refers to a process that reestablishes tube serviceability. Acceptable tube repairs will be performed by the following process:
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a) Westinghouse Laser Welded Sleeving as described in the i proprietary Westinghouse Reports WCAP-13698, Revision 2, )
" Laser Welded Sleeves for 3/4 Inch Diameter Tube Feedring-Type and Westinghouse Preheater Steam Generators, Generic Sleeving Report," April 1995; and 1 WCAP-14469, " Specific Application of Laser Welded I l A Sleeving for the Calvert Cliffs Power Plant Steam l
p Generators," November 1995.
Tube repair includes the removal of plugs that were i previously installed as a corrective or preventive measure.
A tube inspection per Specification 4.4.5.4.c.9 is required prior to returning previously plugged tubes to service,
- b. The steam generator shall be determined OPERABLE after completing the corresponding actions (plug or repair all tubes exceeding the plugging or repair limit and all tubes containing t5 rough-wall
- cracks) required by Table 4.4-2.
4.4.5.5 Reports
- a. Following each inservice inspection of steam generator tubes, the number of tubes plugged or repaired in each steam generator shall be reported to the Commission within 15 days pursuant to 10 CFR 50.4. l
- b. The complete results of the steam generator tube inservice inspection during the report period shall'be submitted to the Commission prior to March 1 of each year pursuant to 10 CFR 50.4.
This report shall include: -
- 1. Number and extent of tubes inspected.
- 2. Location and percent of wall-thickness penetration for each indication of an imperfection.
- 3. Identification of tubes plugged or repaired.
- c. Results of steam generator tube inspections which fall into Category C-3 require verbal notification of the NRC Regional Administrator by telephone within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to resumption of plant operation. The written followup of this report shall l provide a description of investigations conducted to determine l cause of the tube degradation and corrective measures taken to l prevent recurrence and shall be submitted within the next 30 days pursuant to 10 CFR 50.4. l CALVERT CLIFFS - UNIT 1 3/4 4-14 Amendment No. 216
4 3/4.4 REACTOR C0OLANT SYSTEN RASES l
i adequate structural margins against burst during all nomal operating, transient, and accident conditions until the end of the fuel cycle. This evaluation would include the following elements: 1
- 1. An assessment of the flaws found during the previous inspections.
I i 2. An assessment of the structural margins relative to the criteria of Regulatory Guide 1.121. " Bases for Plugging Degraded PWR Steam l j {
Generator Tubes," that can be expected before the end of the fuel 4
cycle or 30 months, whichever comes first.
- 3. An update of the assessment model, as ap)ropriate, based on i comparison of the predicted results of tie steam generator tube integrity assessment with actual inspection results from previous j inspections.
j The plant is expected to be operated in a manner such that the secondary
! coolant will be maintained within those chemistry limits found to result in l negligible corrosion of the steam generator tubes. If the secondary coolant chemistry is not maintained within these limits, localized i
j %g' corrosion may likely result in stress corrosion cracking. The extent of
- . cracking during plant operation would be limited by the limitation of steam 3 generator tube leakage between the Primary Coolant System and the Secondar i ,
l Coolant System (primary-to-secondary leakage = 1 gallon )er minute, total)y .
) Cracks having a primary-to-secondary leakage less than t11s limit during
! , operation will have an adequate margin of safety to withstand the loads imposed during normal operation and by postulated accidents. Operating i plants have demonstrated that primary-to-secondary leakage of I gallon l l perminute can readily be detected by radiation monitors of steam generator blowdown. Leakage in excess of this limit will require plant shutdown and
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$ an unscheduled inspection, during which the leaking tubes will be located and plugged or repaired. Defective tubes may be repaired by a Westinghouse
<\ Laser Welded Sleeve,. The technical bases for Westinghouse Laser Welded D I Sleeve are describied in the proprietary Westinghouse Reports WCAP-13698, Revision 2. " Laser Welded Sleeves for 3/4 Inch Diameter Tube Feedring-Type i and Westinghouse Preheater Steam Generators, Generic Sleeving Report,"
April 1995; and WCAP-14469, " Specific Application of Laser Welded Sleevin t( , } for the Calvert Cliffs Power Plant Steam Generators," November 1995.
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%3$ Wastage-type defects are unlikely with proper chemistry treatment of the secondary coolant. However, even if a defect should develo) in service, it I
will be found during scheduled inservice steam generator tu)e examinations. '
i . N' h Plugging or repair will be required for all tubes with imperfections at or
! y exceeding the plugging or repair limit of 40% of the original tube nominal y wall thickness. If a tube contains a Westinahouse Laser Welded Sleeve >with x imperfection exceeding 40% of nomina' wall thickness, it must be plugged.
N The basis for the sleeve plugging limit is based on Regulatory Guide 1.12 j
Q( N analyses, and is described in the Westinghouser sleeving technical report mentioned above. Steam generator tube inspectHons of operating plants have i demonstrated the capability to reliably detectidegradation_tha_t has
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- CALVERT CLIFFS - UNIT 1 B 3/4 4-4 en ment o. 213 l
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i Insert A: b. ABB-Combustion Engineering Leak Tight Sleeving as J
described in the proprietary ABB-Combustion Engineering i
Report CEN-630-P, Ri: vision 01, " Repair of 3/4" O.D. Steam
- Generator Tubes Using Leak Tight Sleeves," August 1996 Insert B: The technical bases for the Combustion Engineering Leak Tight Sleeve are described in the proprietary ABB-Combustion Engineering Report CEN-630-P, Revision 01,
- Repair of 3/4" O.D. Steam Generator Tubes Using Leak Tight Sleeves," August 1996 4
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1 ATTACHMENT (2) !
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l UNIT 2 MARKED-UP TECHNICAL SPECIFICATION PAGES l
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- Revised Pages
- 3/4 4-14 1
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4 i Baltimore Gas & Electric Company Docket Nos. 50-317 and 50-318 March 6,1997 i
3/4.4 REACTOR C0OLANT SYSTEM SURVEILLANCE REQUIREMENTS (Continued)
' 10. Tube Reonir. refers to a )rocess that reestablishes tube servicea)111ty. Accepta)1e tube repairs will be perfonned by the following process:
a) Westinghouse Laser Welded Sleeving as described in the proprietary Westinghouse Reports WCAP-13698, Revision 2
" Laser Welded Sleeves for 3/4 Inch Diameter Tube j Feedring-Type and Westinghouse Preheater Steam Generators, Generic Sleeving Report," April 1995; and WCAP-14469, " Specific Application of Laser Welded j Sleeving for the Calvert Cliffs Power Plant Steam p Generators," November 1995.
Tube repair includes the removal of plugs that were previously installed as a corrective or preventive measure.
A tube inspection per Specification 4.4.5.4.a.9 is required prior to returning previously plygged tubes to service.
- b. The steam generator shall be detennined OPERABLE after completing the corresponding actions (plug or repair all tubes exceeding the plugging er repair limit and all tubes containing through-wall cracks) required by Table 4.4-2.
4.4.5.5 Reports
- a. Following each inservice inspection of steam generator tubes, the number of tubes plugged or repaired in each steam generator shall be reported to the Commission within 15 days pursuant to 10 CFR 50.4. l
- b. The complete results of the steam generator tube inservice inspection during the report period shall be submitted to the Coninission prior to March 1 of each year pursuant to 10 CFR 50.4.
This report shall include: _
- 1. Number and extent of tubes inspected.
- 2. Location and percent of wall-thickness penetration for each indication of an imperfection.
g 3. Identification of tubes plugged or repaired.
- c. Results of steam generator tube inspections which fall into Category C-3 require verbal notification of the NRC Regional Administratcr by telephone within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to resumption of plant operation. The written followup of this report shall provide a description of investigations conducted to determine cause of the tube degradation and corrective measures taken to prevent recurrence and shall be submitted within the next 30 days pursuant to 10 CFR 50.4. l CALVERT CLIFFS - UNIT 2 3/4 4-14 Amendment No. 193
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4 3/4.4 REACTOR COOLANT SYSTEM l BASES adequate structural margins against burst during all nonnal operating, transient, and accident conditions until the end of the fuel cycle. This evaluation would include the following elements:
- 1. An assessment of the flaws found during the previous inspections.
- 2. An assessment of the structural margins relative to the criteria of i Regulatory Guide 1.121 " Bases for Plugging Degraded PWR Steam Generator Tubes," that can be expected before the end of the fuel cycle or 30 months, whichever comes first.
! 3. An update of the assessment model, as ap)ropriate, based on i
comparison of the predicted results of tie steam generator tube i integrity assessment with actual inspection results from previous inspections.
The plant is expected to be operated in a manner such that the secondary coolant will be maintained within those chemistry limits found to result in negligible corrosion of the steam generator tubes. If the secondary coolant chemistry is not maintained within these limits, localized corrosion may likely result in stress corrosion cracking. - The extent of i
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)j cracking during plant operation would be limited by the limitation of steam generator tube leakage between the Primary Coolant System and the Secondary a
Coolant System (primary-to-secondary leakage = 1 gallon erminute, total).
4 Cracks having a primary-to-secondary leakage less than t is limit during
% operation will have an adequate margin of safety to withstand the loads imposed during nonnal operation and by postul'ated accidents. Operating
- plants have demonstrated that primary-to-secondary leakage of 1 gallon per y h minute can readily be detected by radiation monitors of steam generator
- .g blowdown. Leakage in excess of this limit will require plant shutdown and d
an unscheduled inspection, during which the leaking tubes will be located and plugged or repaired. Defective tubes may be repaired by a Westinghouse i Laser Weided Sleeve The technical bases for Westinghouse Laser Welded
% Sleeve are described in the proprietary Westinghouse Reports WCAP-13698, i
Revision 2, " Laser Welded Sleeves for 3/4 Inch Diameter Tube Feedring-Type s
' and Westinghouse Preheater Steam Generators, Generic Sleeving Report,"
April 1995; and WCAP-14469, " Specific Application of Laser Welded Sleevi for the Calvert Cliffs Power Plant Steam Generators," November 1995.
Wastage-type defects are unlikely with proper chemistry treatment of th i.s k secondary coolant. However, even if a defect should develo) in service, it gN will be found during scheduled inservice steam generator tu)e examinations.
g Plugging or repair will be required for all tubes with imperfections at or exceeding the plugging or repair limit of 40% of the tube original nominal wall thickness. If a tube contains a Westinghouse Laser Welded Sleeve with Imperfection exceeding 40% nominal wall thickness, it must be plugged. The basis for the sleeve plugging limit is based on Regulatory Guide 1.121 analyses, and is described in the Westinghousers leeving technical report mentioned above. Steam generator tube inspections of operating plants have demonstrated the capability to reliably detect degradation that has A
CALVERT CLIFFS - UNIT 2 B 3/4 4-4 fjt))i MW'-
Amend No. 190
Insert A: b. ABB-Combustion Engineering Leak Tight Sleeving as described in the proprietary ABB-Combustion Engineering Report CEN-630-P, Revision 01, " Repair of 3/4" O.D. Steam Generator Tubes Using Leak Tight Sleeves," August 1996 Insert B: The technical bases for the Combustion Engineering Leak Tight '
Sleeve are described in the proprietary ABB-Combustion Engineering Report CEN-630-P, Revision 01, " Repair of 3/4" O.D. Steam Generator Tubes Using Leak Tight Sleeves," August 1996 l l
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j ABB COMBUSTION ENGINEER.ING PROPRIETARY AFFIDAVIT i
4 FOR ATTACHMENT 4, i
PURSUANT TO 10 CFR 2.790 i
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Baltimore Gas & Electric Company Docket Nos. 50-317 and 50-318 March 6,1997
AFFIDAVIT PURSUANT
, TO 10 CFR 2.790 I, Ian C. Rickard, depose and say that I am the Director, Operations Licensing, of Combustion Engineering, Inc., duly authorized to make this affidavit, and have reviewed or caused to have reviewed the information which is identified as proprietary and referenced in the paragraph immediately below. I am submitting this affidavit in conjunction with the application of Baltimore Gas and Electric and in conformance with the provisions of 10 CFR 2.790 of the Commission's regulations.
The information for which proprietary treatment is sought is contained in the following document:
CEN-630-P, Rev. 01, " Repair of 3/4" O.D. Steam Generator Tubes Using Leak Tight Sleeves," November 1996.
This document has been appropriately designated as proprietary.
I have personal knowledge of the criteria and procedures utilized by Combustion Engineering in designating information as a trade secret, privileged or as confidential
- commercial or financial information.
Pursuant to the provisions of paragraph (b)(4) of Section 2.790 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure, included in the above referenced document, should be withheld.
- 1. The information sought to be withheld from public disclosure, is owned and has been held in confidence by Combustion Engineering. It consists of the details concerning the fabrication process, material properties, and
. _ . . -. . _ _ _ ~__
I surveillance data used to develop an approach to ascertain the embrittlement l of reactor vessels.
- 2. The information consists of test data or other similar data concerning a process, method or component, the application of which results in substantial competitive advantage to Combustion Engineering.
- 3. The information is of a type customarily held in confidence by Combustion Engineering and not customarily disclosed to the public. Combustion Engineering has a rational basis for determining the types of information customarily held in confidence by it and, in that connection, utilizes a system to determine when and whether to hold certain types of information in
- 1 confidence. The details of the aforementioned system were provided to the Nuclear Regulatory Commission via letter DP-537 from F. M. Stern to Frank Schroeder dated December 2,1974. This system was applied in determining that the subject document herein is proprietary.
- 4. The information is being transmitted to the Commission in confidence under the provisions of 10 CFR 2.790 with the understanding that it is to be received in confidence by the Commission.
- 5. The information, to the best of my knowledge and belief, is not available in public sources, and any disclosure to third parties has been made pursuant to regulatory provisions or proprietary agreements which provide for maintenance of the information in confidence.
- 6. Public disclosure of the information is likely to cause substantial harm to the competitive position of Combustion Engineering because:
- a. A similar product is manufactured and sold by major pressurized water reactor competitors of Combustion Engineering.
- b. Development of this information by Combustion Engineering required tens of thousands of dollars and thousands of
4
, manhours of effort. A competitor would have to undergo similar
' expense in generating equivalent information.
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! c. In order to acquire such information, a competitor would also require considerable time and inconvenience to develop the i design, development, and installation process for a welded sleeve for repairing 3/4 inch O.D. steam generator tubes.
- d. The information consists of the design, development, and s
installation process for a welded sleeve for repairing 3/4 inch O.D. steam generator tubes, the application of which provides i
- . a competitive economic advantage. The availability of such ;
l information to competitors would enable them to modify their I product to better compete with Combustion Engineering, take -
i marketing or other actions to improve their product's position or impair the position of Combustion Engineering's product, and I avoid developing similar data and analyses in support of their l processes, methods or apparatus.
- e. In pricing Combustion Engineering's products and services, l
j significant research, development, engineering analytical, manufacturing, licensing, quality assurance and other costs l
and expenses must be included. The ability of Combustion Engineering's competitors to utilize such information without
! similar expenditure of resources may enable them to sell at I prices reflecting significantly lower costs.
J
- f. Use of the information by competitors in the international a marketplace would increase their abi!ity to market nuclear 2-steam supply systems by reducing the costs associated with 4 their technology development. In addition, disclosure would have an adverse economic impact on Combustion r i i
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Engineering's potential for obtaining or maintaining foreign s )
licensees. l Further the deponent sayeth not.
vis
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- Director, Operations Licensing l
Sworn to before me this 3 day of 4Azt , .1997
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Notary Public My commission expires: _ 3/ 99 i
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ATTACHMENT (4)
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i PROPRIETARY ABB COMBUSTION ENGINEERING i REPORT CEN-630-P, REVISION 01
" REPAIR OF 3/4" O.D. STEAM GENERATOR TUBES l
{ USING LEAK TIGHT SLEEVES"
) AUGUST 1996 l
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Baltimore Gas & Electric Company Docket Nos. 50-317 and 50-318 March 6,1997
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I NON-PROPRIETARY ABB COMBUSTION ENGINEERING )
J RE' PORT CEN-630-NP, REVISION 01 i i
" REPAIR OF 3/4" O.D. STEAM GENERATOR TUBES USING LEAK TIGHT SLEEVES" l i
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l AUGUST 1996 k
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l Baltimore Gas & Electric Company Docket Nos. 50-317 and 50-318 March 6,1997
1 NON-PROPRIETARY CEN-630-NP Revision 01 1
COMBUSTION ENGINEERING, INC.
November,1996 Reoair of 3/4" O.D.
Steam Generator Tubes Using Leak Tinht Sleeves FINAL REPORT Combustion Engineering, Inc.
Nuclear Operations Windsor, Connecticut 9'c!L i20 sin ' nwsy
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LEGAL NOTICE
. THIS REPORT WAS PREPARED AS AN ACCOUNT OF WORK SPONSORED BY i ABB COMBUSTION ENGINEERING. NEITHER ABB COMBUSTION l ENGINEERING NOR ANY PERSON ACTING ON ITS BEHALF:
A. MAKES ANY WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED INCLUDING THE WARRANTIES OF FITNESS FOR A PARTICULAR l PURPOSE OR MERCHANTABILITY, WITH RESPECT TO THE
, ACCURACY, COMPLETENESS, OR USEFULNESS OF THE INFORMATION CONTAINED IN THIS REPORT, OR THAT THE USE OF ANY
, INFORMATION, APPARATUS, METHOD, OR PROCESS DISCLOSED IN THIS REPORT MAY NOT INFRINGE PRIVATELY OWNED RIGHTS; OR i
B. ASSUMES ANY LIABILITIES WITH RESPECT TO THE USE OR FOR DAMAGES RESULTING FROM THE USE OF, ANY INFORMATION, APPARATUS, METHOD OR PROCESS DISCLOSED IN THIS REPORT.
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1 a . ABSTRACT
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). 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 j 690 sleeve which spans the section or sections of the original steam generator tube which
- 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.
i This report details analyses and testing performed to verify the adequacy of repair sleeves for
- installation in a 3/4 inch O.D. nuclear steam generator tube. These verifications show tube j sleeving to be an acceptable repair technique.
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1 TABLE OF CONTENTS l
Section Title Page
1.0 INTRODUCTION
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1.1 PURPOSE 1-1
1.2 BACKGROUND
1-2
-1.3 ACRONYMS 1-2 2.0
SUMMARY
AND CONCLUSIONS 2-1 l
3.0 ACCEPTANCE CRITERIA 3-1 4.0 DESIGN, DESCRIPTION OF SLEEVES AND INSTALLATION
, -EQUIPMENT 4-1 4.1 SLEEVE DESIGN DESCRIPTION 4-1 4.2 SLEEVE MATERIAL SELECTION 4-1 4.3 SLEEVE-TUBE ASSEMBLY 4-2 4.4 PLUGGING OF A DEFECTIVE SLEEVED TUBE 4-3 4.5 SLEEVE INSTALLATION EQUIPMENT 4-3
, 4.5.1 Remote Controlled Manipulator 4-4 4.5.2 Tool Delivery Equipment 4-4 4.5.3 Tube Brushing - Cleaning Equipment 4-5 4.5.4 Tube Rolling Equipment 4-5 Sleeve Expansion Equipment 4-6
) 4.5.5 4.5.6 Sleeve Welding Equipment 4-6 4.5.7 Nondestructive Examination 4-7 ii
4 TABLE OF CONTENTS (Continued)
Section Title Page 4.5.8 Post-Weld Heat Treatment Equipment 4-7 4.5.9 Sleeve Rolling Equipment 4-7.
1 4.6 ALARA CONSIDERATIONS 4-8
4.7 REFERENCES
TO SECTION 4.0 4-9 5.0 SLEEVE EXAMINATION PROGRAM 5-1 5.1 ULTRASONIC INSPECTION 5-2 1
5.1.1 Summary and Conclusions 5-2
) 5.1.2 Ultrasonic Evaluation 5-3 5.1.3 Test Equipment 5-3 5.2 EDDY CURRENT INSPECTION 5-4 4
._ 5.2.1 Background 5-4 5.2.2 Plus Point Probe Qualification Study 5-5 5.3 VISUAL INSPECTION 5-6 5.3.1 Summary and Conclusions 5-6 5.3.2 Cleaning Inspection 5-7 5.3.3 Weld Examination 5-7
5.4 REFERENCES
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, . TABLE OF CONTENTS (Continued) 2 Section Title Page i
l 6.0 SLEEVE-TUBE CORROSION TEST PROGRAM 6-1 I 6.1
SUMMARY
AND CONCLUSIONS 6-1 l l
6.2 TEST DESCRIPTION AND RESULTS 6-1
- 6.2.1 Primary Side tests 6-1 )
i l 6.2.1.1 Pure Water Stress Corrosion Cracking Tests 6-3 1 l
6.2.1.2 Above the Tubesheet (ATS) Weld Capsule Tests 6-3 )
6.2.1.3 TSP Sleeve Weld Capsule Tests 6-4 j i
, 6.2.1.4 Summary-Primary Coolant Corrosion Performance 6-5 l l
6.2.2 Secondary Side Tests 6-6 l l
l 6.2.2.1 Modified Huey Tests 6-6 6.2.2.2 Capsule Tests 6-7 l
i 6.'2.2.3 Sodium Hydroxide Fault Autoclave Tests 6-8 6.2.2.4 Summary 6-9 I l
6.3 REFERENCES
FOR SECTION 6.0 6-10 l l
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I TABLE OF CONTENTS (Continued) j Section Title Page 7.0 MECHANICAL TESTS OF SLEEVED STEAM GENERATOR 7-1 TUBES 7.1
SUMMARY
AND CONCLUSIONS 7-1 I 7.2 CONDITIONS TESTED 7-1 7.3 WELDED SLEEVE TEST PARAMETERS AND RESULTS 7-1 I 7.3.1 Axial Pull Tests 7-1 7.3.2 Collapse Testing 7-2 7.3.3 Burst Testing 7-3 !
7.3.4 Load Cycling Tests 7-3 8.0 STRUCTURAL ANALYSIS OF SLEEVE-TUBE ASSEMBLY 8-1 8.1
SUMMARY
AND CONCLUSIONS 8-1 8.1.1 Design Sizing 8-1 8.1.2 Detailed Analysis Summary 8-1 8.2 LOADINGS CONSIDERED 8-7 8.2.1 Upper Tube Weld Pull-Out Load 8-7 8.2.2 Lower Sleeve Rolled Section Push-Out Load 8-8 8.2.3 Weld Fatigue 8-8 V
1 TABLE OF CONTENTS (continued)
. SECTION TITLE PAGE 8.3 EVALUATION FOR ALLOWABLE SLEEVE WALL 8-8
. DEGRADATION USING REGULATORY GUIDE 1.121 8.3.1 Normal Ooeration Safety Marnins 8-8 8.3.2 Postulated Pioe Ruoture Accidents 8-10 8.3.3 Average Minimum Weld Height Reauirements 8-11 8.4 EFFECTS OF TUBE LOCK-UP ON SLEEVE LOADING 8-13 8.4.1 Sleeved Tube in " Worst" Case ABB/CE Plant. Free at Egg Crate 8-13 8.4.2 Sleeved Tube in " Worst" Case Westinghouse Plant. Free at Sucoort Plate 8-14 8.4.3 Sleeved Tube in " Worst" Case ABB/CE Plant. 8-15 Lock-uo at First Een Crate 8.4.4 Sleeved Tube in " Worst" Case Westinghouse Plant. 8-15 Lock-un at First Sunoort 8.4.5 Effect of Tube Prestress Prior to Sleeving 8-22 8.4.6 Imwer Sleeve Rolled or WeH Section Pushout 8-22 Due to Restrained Thermal Exoansion
- 8.5 SLEEVED TUBE VIBRATION 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 Uoner Sleeve / Tube Weld 8-27 8.6.2 Fatigue Evaluation of Lower Sleeve Rolled Section 8-31 vi
TABLE OF CONTENTS (Continued) e SECTION TITLE PAGE
8.7 REFERENCES
FOR SECTION 8.0 8-34 8A FATIGUE EVALUATION OF UPPER TUBE / SLEEVE WELD 8A-1 8B SLEEVE HISTORY DATA 8B-1 9.0 SLEEVE INSTALLATION VERIFICATION 9-1 9.1
SUMMARY
AND CONCLUSIONS 9-1
- 9.2 SLEEVE-TUBE INSTALLATION SEQUENCE 9-1 9.2.1 Exoansion/ Roll Transition Zone Sleeve With Rolled Lower .ioSt 9-1 9.2.2 Tube Suonort Sleeve 9-2 9.3 WELD INTEGR11Y 9-2 9.3.1 Cleaning Oualification 9-2 9.3.2 Exoansion Oualification 9-3 9.3.3 Weld Oualification 9-3 9.3.4 Ultrasonic Testine Oualification 9-4 9.3.5 Post Weld Heat Treat Oualifical!QD 9-4 9.3.6 Summary 9-6 Vii
TABLE OF CONTENTS (Continued)
TITLE PAGE
>C110N 9-7 4 ROLLED JOINT INTEGRITY 9-7 5 COMMERCIAL SLEEVE INSTALLATION l 9-7 l 6 REFERENCES FOR SECTION 9.0 10-1
).0 EFFECT OF SLEEVING ON OPERATION i
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l LIST OF TdBLES i
l TABLE NO. TABLE PAGE i* 1 1-1 ACRONYMS USED IN REPORT 1-3 l
2-1 INSTALLATIONS OF ABB-CENO WELDED SLEEVE 2-3 I
3-1 REPAIR SLEEVING CRITERIA 3-2 !
l 5-1 ACRONYMS USED IN ET ANALYSIS 5-8 !
6-1 STEAM GENERATOR TUBE SLEEVE CORROSION TESTS 6-2 1
6-2 SLEEVE / TUBE CAPSULE SCC TESTS 6-4
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6-3 SECONDARY SIDE STEAM GENERATOR TUBE SLEEVE 6-8 CAPSULE TESTS 7-1 SLEEVE-TUBE ASSEMiq.Y MECHANICAL TESTING 7-5 RESULTS i
8-1
SUMMARY
OF SLEEVE AND WELD ANALYSIS RESULTS 8-4 8-2
SUMMARY
OF LOWER JOINT (WELDED AND ROLLED)
DESIGN, ANALYSIS,AND TEST RESULTS 8-6 8-3A 26 INCH SLEEVE AXIAL MEMBER PHYSICdL PROPERTIES FOR " WORST" CASE ABB/CE PLANT 8-16 !
8-3B 26 INCH SLEEVE AXIAL MEMBER PHYSICAL PROPERTIES FOR " WORST" CASE WESTINGHOUSE PLANT 8-17 8-4A AXIAL LOADS IN SLEEVE WITH TUBE N_QT LOCKED !
INTO EGG CRATE FOR " WORST" CASE ABB/CE PLANT 8-18 8-4B AXIAL LOADS IN SLEEVE WITH TUBE NOT LOCKED i INTO TUBE SUPPORT FOR " WORST" CASE WESTINGHOUSE 8-19 PLANT -
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LIST OF TABLES TABLE NO. TABLE E6_GE 8-5A AXIAL LOADS IN SLEEVE WITH TUBE LOCKED INTO EGG CRATE FOR " WORST" CASE ABB/CE PLANT 8-20 8-5B AXIAL LOADS IN SLEEVE WITH TUBE . LOCKED INTO TUBE SUPPORT FOR " WORST" CASE ENVELOPMENT 8-21 8-6 UPPER SLEEVE WELD-TRANSIENTS CONSIDERED 8-29 FOR AN ABB/CE PLANT 8-7 UPPER SLEEVE WELD-TRANSIENTS CONSIDERED 8-30 FOR A WESTINGHOUSE PLANT 8-8 LOWER SLEEVE SECTION-TRANSIENTS CONSIDERED 8-32 FOR AN ABB/CE PLANT 8-9 LOWER SLEEVE SECTION-TRANSIENTS CONSIDERED 8-33 FOR A WESTINGHOUSE PLANT 8A-1 A STRESS RESULTS,100% STEADY STATE 8A-4 8A-1B STRESS RESULTS,15% STEADY STATE 8A-5 8A-IC STRESS RESULTS,0% STEADY STATE 8A-6 8A-1C STRESS RESULTS FEEDWATER CYCLING 8A-7
. 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-ll 8A-3B STRESS RESULTS,15% STEADY STATE (0.020" Weld) 8A-12 8A-3C STRESS RESULTS,0% STEADY STATE (0.020" Weld) 8A-13 8A-3D 8A-14 STRESS RESULTS FEEDWATER CYCLING (0.020" Weld) 8A-4A RANGE OF STRESS AT WORST LOCATIONS (0.020" Weld) 8A-15 X
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LIST OF TABLES 1
TABLE _ NO. TABLE PAGE i
j ' 8A-4B FATIGUE EVALUATION AT WORST LOCATIONS (0.020" Weld) 8A-16 9-1 0.875 0.D. SLEEVED TUBE PWHT DATA 9-9
! 9-2 0.750" O.D. SLEEVED TUBE PWHT DATA, I TUBES LOCKED AT ALL SUPPORTS 9-10 i
e 9-3 ABB CENO S/G SLEEVE OPERATING HISTORY 9-11 10-1 HYDRAULIC EQUIVALENCE RATIOS l 10-2 1
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4 LIST OF FIGURES J
FIGURE NO. TITLE PAGE
? '
! 4-1 EXPANSION / ROLL TRANSITION ZONE SLEEVE 4-10 t
i 4-2 TUBE SUPPORT SLEEVE 1
4-11 4-3 EXPANSION / ROLL TPANSITION ZONE 4-12
- SLEEVE INSTALLATION d
4-4 TUBE SUPPORT SLEEVE INSTALLATION 4-13
)
4-5 MANIPULATOR AND TOOL DELIVERY SYSTEM 4-14 l i 4-6 TOOL DELIVERY EQUIPMENT 4-15
) 4-7 TUBE CLEANING EQUIPMENT '
4-16 a
4-8 SLEEVE EXPANSION EQUIPMENT 4-17 4-9 SLEEVE WELDING HEAD ASSEMBLY 4-18
! 4-10 SLEEVE WELDING HEAD POWER SUPPLY UNIT 4-19 L
4 11
'O l ULTRASONIC TEST EQUIPMENT 4-20
- 4-12 VISUAL TEST EQUIPMENT 4-21 i
4-13 POST WELD HEAT TREAT EQUIPMENT 4-22 4-14 SLEEVE ROLLING EQUIPMENT - STRAIGHT 4-23 4-15 SLEEVE ROLLING EQUIPMENT - CURVED 4-24 Xii
LIST OF FIGURES (Continued)
.e FIGURE NO. TITLE EAQE 5-1 NDE PROCESS FLOW CHART 5-9 5-2 ET PROCESS FLOW CHART 5-10 5-3 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 6-1 PURE WATER CORROSION TEST SPECIMEN 6-11 6-2 ATS WELD CAPSULE TEST SPECIMEN 6-12 6-3 TSP WELD CAPSULE TEST SPECIMEN 6-13 6-4 CAUSTIC CORROSION AUTOCLAVE TEST SPECIMEN 6-14 8-1 WELDED SLEEVE / TUBE ASSEMBLY 8-35 8-2 SYSTEM SCHEMATIC FOR " WORST" CASE ABB/CE PLANT 8-36 8-3 SYSTEM SCHEMATIC FOR " WORST" CASE WESTINGHOUSE 8-37 PLANT 8-4 STIFFNESS MODEL OF SLEEVE AND LOWER TUBE 8-38 8-5 STIFFNESS MODEL OF UPPER TUBE AND SURROUNDING TUBE 8-39 8-6 FINITE ELEMENT MODEL OF UPPER TUBE WELD 8-40 Xiii
. .. .. . . . . . - - - . . . . - . . ~ . . - - - - . . . .. . - - .... .
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, LIST OF FIGURES (Continued) e FIGUR,E NO. TITLE PAGE 8A-1 NODE AND STRESS CUT IDENTIFICATION 8A-3 8A-2 NODE AND STRESS CUT IDENTIFICATION FOR 20 MIL WELD 8A-10 9-1 POST HEAT TREAT-BRUSHED SECTION 9-12 I 9-2 0.875 O.D. LOCKED TUBE TEST 9-13 l
9-3 0.875 0.D. LOCKED TUBE TEST, TEMPERATURE AND AXIAL LOAD PROFILE 9-14 l
9-4 0.750 0.D. LOCKED TUBE MOCKUP 9-15 9-5 0.750 O. D. TYPICAL TEMPERATURE PROFILES '9-16 1
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LIST OF APPENDICES
- APPENDIX NO. NO.OF
. PAGES A EROCESS AND WELD OPERATOR OUALIFICATION A-1 i
- - A.2 REFERENCES TO APPENDIX A A-1 4 i
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-4 1. INTRODUCTION-3
- 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 generctors 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 or different kind of accident and will not reduce the existing margin of safety.
ABB Combustion Engineering (ABB-CE) provides two types of leak tight sleeves for repair of 3/4 inch O.D. steam generator tubes with full depth rolled or expanded tubesheetjoints. 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 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 criteria are met.
The effect of sleeve installation on steam generator heat removal capability and system flow rate are discussed in this report. Heat removal capability and system flow rate was I considered for installation of one to three sleeves in a steam generator tube.
1 Plugs will be installed if sleeve installation is not successful or if there is unacceptable l 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.
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1.2 BACKGROUND
e The operation of Pressurized Water Reactor (PWR) steam generators has in some instances, resulted in localized corrosive attack on the inside (primary 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 structural reauirements. Thus it has not been necessary to take corrective action unless structural limits were being approached.
Historically, 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 steam generator tubing degradation and the tube plugging criteria accounts for ET measurement uncertainty.
Installation of steam generator tube plugs removes the heat transfer surface of the plugged tube from service und leads to a reduction in the primary coolant flow rate available for core cooling. Installation of welded and/or welded and hard rolled steam generator sleev,:s does not significantly affect the heat transfer removal capability of the tube being sieeved and a large number of sleeves can be installed without significantly affecting primary flow rate 1.3 ACRONYMS Table 1-1 (along with Table 5-1) contains a list of the acronyms used throughout this report.
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1-2 a
l TABLE l-1 ACRONYMS USED IN REPORT
, + POINT: + Point ATS: Above the Tubesheet EFPH: Effective Full Power Hours EPPY: Effective Full Power Years ET: Eddy Current Testing 4 ETZ: Expansion / Roll Transition Zone LOF: Lack of Fusion PWHT: Post Weld Heat Treatment TS: Tube Support UT: Ultrasonic Testing VT: Visual Testing 4
1-3
e
- 2.
SUMMARY
AND CONCLUSIONS
. The sleeve dimensions, materials and joints were designed to t'ne applicable ASME Boiler 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 performing the analysis and l test program which, if met, would prove that these sleeve types are an acceptable repair I technique. These criteria conformed to the stress limits and margins of safety of Section l III of the ASME 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 i criteria. l Evaluation of the sleeved tubes indicates no detrimental effects on the riteve tube l assembly resulting from reactor system flow, coolant enemistries, or thermal and pressure conditions. Structural analyses of the sleeve-tube assembly, using the demonstrated margins of safety, have established its integrity under .ormal and accident 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 ASME 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
J Ringhals Unit 2 in May 1984. ABB-CE's sleeving history is shown in Table 2-1.
The success rate for all installed sleeves is 98%. Since 1985, no sleeve which
.. has been accepted based on NDE has been removed from service due to service induced degradation.
- If a steam generator tube which has been sleeved is found to require plugging to j remove it from service, a standard steam generator tube plug can be installed.
No discussion or evaluation of the standard tube plug is provided as part of this l document.
In conclusion, steam generator tube repair by installation of any of the two types of sleeves described herein is established as an acceptable method.
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TABLE 2-1 INSTALLATIONS OF ABB-CENO WELDED SLEEVE INSTALLED PLANT DATE QUANT 11 Y TYPE
- KRSKO 6/96 273 TS 188 ETZ Byron 1 4/96 3527 ETZ Prairie Island 1 2/96 253 WTS ANO2 10/95 711 ETZ Zion 1 10/95 911 WTS Zion 2 1/95 162 WTS KRSKO 6/93 160 ETZ 14 TS Ginna 4/93 51 WTS Zion 2 12/92 172 WTS Prairie Island 1 11/92 158 WTS Ginna 4/92 175 WfS 63 Curved WTS Zion 1 4/92 124 WTS Kewaunee 3/92 16 Curved WTS Ringhals 3 7/91 46 ETZ 22 TS Ginna 4/90 192 WTS
. 48 Curved WTS Zion 2 4/90 82 WTS Prairie Island 1 1/90 63 WTS Zion 1 9/89 445 WTS Ginna 4/89 395 WTS 107 Curved WTS Prairie Island 1 9/88 74 WTS l
2-3
I TABLE 2-1 (cont.)
INSTALLATIONS OF ABB-CENO WELDED SLEEVE INSTALLED PLANT DATE QUANTITY TYPE Ringhals 2 5/87 571 WTS Prairie Island 1 4/87 27 WTS Ginna 2/87 105 WTS Zion 1 10/86 128 WTS Ringhals 2 5/86 599 WTS Ginna 2/86 36 WTS Ringhals 2 5/85 59 WTS Ringhals 2 5/84 18 WTS
- Straight sleeves unless otherwise noted O
2-4
. 3. ACCEPTANCE CRITERIA T,he objectives of installing sleeves in steam generator tubes are twofold. The sleeve e
must maintain structural imegrity of the steam generator tube during normal operating and postulated accident conditions. Additionally, the sleeve must prevent leakage in the cvent of a through-wall defect in the steam generator tube. N merous u tests and analyses were performed to demonstrate the capability of the sleeves to perform these functions under normal operating and postulated accident conditions. I Operating conditions used to bound the CE steam generators are defined as:
(Pressure and temperature differences were considered in determining bounding conditions)
Primary Side: 611*F (operating) 2250 psig (operating) l (Hot Side)
Secondary Side: 506 F (100% load) 815 psig (100% load) l Operating conditions used to bound the W steam generators are defined as:
(Pressure and temperature differences were considered in determining bounding conditions)
Primary Side: 620 F (operating) 2250 psig (operating)
(Hot Side)
Secondary Side: 526.5 F (100% load) 815 psig (100% load)
Table 3-1 provides a summary 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 indicating the minimum level with which the sleeves sur-passed the criteria are tabulated. The section of this report describing tests or analyses which verify the characteristics for a particular criterion is referenced in the table.
3-1
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i TABLE 3-1
. REPAIR SLEEVING CRITERIA Criterion Justification Results Section
. 1. Sleeve is leak tight Leakage between 4.0 primary and secondary side is prevented.
- 2. Sleeve-tube assembly Sleeve tube assembly 8.0 functional integrity must meets applicable ASME be maintained. Code requirements.
- 3. Axial load cycle without Bounds cycle loading 7.0 weld joint or rolled joint from normal operating failure. and transient cycling.
- 4. Pressurization of annulus Prevention of sleeve 7.0 between sleeve and tube failure for through wall does not collapse sleeve at defect in tube wall.
1500 psig.
- 5. Pressurize sleeve (without Factor of safety of three 7.0 tube) to 4800 psig without for N.O. conditions.
bursting.
- 6. Exposure of sleeve-tube Sleeve-tube assembly 6.0 assembly to various required to function primary and secondary under coolant
+ chemistries without loss chemistries of functional integrity.
. 7. Non-destructive Periodic examination of 5.0 examination of tube and tubes and sleeves sleeve to levels of required to verify detectability required to structural adequacy show structural adequacy.
- 8. Welded sleeve installation Sleeve repair should not 10.0 does not significantly reduce power removal affect system flow rate or capability of reactor or heat transfer capability of steam generator below the steam generator. rated value.
3-2
. 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, chnwn 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 [ band of nickel and a band of metal oxide on one end. The nickel band improves sealing of the sleeve when the lower end is hard rolled into the expanded or rolled portion of the parent tube while the rough surface of the metal oxide provides a strong mechanical joint. ]
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 II 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'sjustification for selection of this material and condition is based on the data contained in Reference 4.7.1.
4-1
4 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 i ip of the tubesheet. If
, defects exist at a tube support or egg crate support plate, as viell 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. [
]
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l When it is considered to be of benefit (based on steam generator primary and
. . secondary side conditons), a post _ weld heat treatment of the sleeve weld will be added -
I l weld joint is heated in the range of [ ] As described in j , 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 i growth or sensitization. This treatment is similar to that utilized in some operating ;
units to heat treat the tight radius U-bends. ;
i .
l i- Qualification of the sleeve welding process is in accordance with the procedure i j described in Appendix A. l 2 ;
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i 4.4 PLUGGING OF A DEFECTIVE SLEEVED TUBE l 1 l If a sleeve or sleeved tube is found to have an unrepairable defect, the tube can be i j 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 i The equipment used for remote installation of sleeves in a steam generator is made up
. of the following basic systems. These systems are:
i 1. Remote Controlled Manipulator l
=
9 4-3 rg
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- These systems, when used together, allow installation of the sleeves without personnel ,
entering the steam generator. In this way, personnel exposure to radiation is held to a l I. minimum.
The tooling and methods described in the following sections represent the_ present .
technology for leak tight sleeve installation. As technological advances are made in I l, sleeve installation, the new tooling and/or processes may be utilized after they have I l been laboratory-verified to provide improved sleeve installation methods. j 4.5.1 Remote Coritrolled Manipulator i 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 j- arm. The manipulator leg is installed between the tube sheet and bottom of the r primary head and provides axial (vertical) movement of the arm. The manipulator arm j is divided into the head arm, probe arm and a swivel arm. Each arm is moved l independently with encoder position controlled electric motors. The swivel arm allows !
motion for tool alignment in both square pitch and triangular pitch tube arrays. .
I 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 Equipment The purpose of the tool delivery equipment is to support and vertically position the q various tools required for the sleeving operation and to provide controlled rotation 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 fitting 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
- . ._ _ . - . - _ - . . . ~ - _ . - . - -- - -... .
mounting plate to the tube sheet. Proper alignment of the tool mounting plate to the
, 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 platform.
4.5.3 Tube Brushine-Cleaninn Eauinment 4.5.4 Tube Rolline Eauinment 4-5
4.5.5 Sleeve Exnansion Eauioment l D
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l 4.5.6 Sleeve Welding Eauinment p
4-6
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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 4-12).
. 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 l 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 I I
use of a boroscope or micro camera system delivered and rotated by the probe pusher.
Inspection data is stored on video tape. j l
4.5.8 Post-Weld Heat Treatment Equipment 0
4.5.9 Sleeve Rolling Equipment 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 stop 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 on the manipulator, [ ] may be used in the central tubesheet region 4-7
_- ~ __ _ _ _ _ __ _ . _ _ _ -.. ._ _ _ -- ~ _ _
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F j while a curved elevator [ ] is used for the periphery. Although' the curved elevator is used specifically for the periphery, it may be used at any tube location.
' o 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 l
. rolling tool are verified on the torque calibration unit prior to rolling of the sleeves.
4 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 .
i hydraulically expanded during sleeve installation. The approximately 1-1/4 inch long s-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 tightjoint. A record of the rolling tool torque is made for further evaluation of j the rolling process on the individual sleeves. A rolled joint which fails to meet the j ' acceptance criteria may be re-rolled, i
j 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 l the manipulator. The probe pusher is designed to quickly engage the individual i
sleeving tools. The tools are simple in design and all sleeving operations are 'I 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. This 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
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4.7 REFERENCES
TO SECTION 4.0
- 4.7.1 Alloy 690 for Steam Generator Tubing Applications, 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", Japan Society of Corrosion Engineeriqq,
- 2_8, 2 (1979).
I 4.7.3 Airey, G. P., " Optimization of Metallurgical Variables to Improve the Stress
, Corrosion Resistance of Inconel 600", Electric Power Research Institute Research Program RP1708-1 (1982).
I 4.7.4 Airey, G. P., Vaia, A. R., and Aspden, R. G., "A Stress Corrosion Cracking Evaluation of Inconel 690 for Steam Generator Tubing Applications", Nuclear l Technology, 55, (November, 1981) 436.
i
! 4.7.5 Hunt, E.S. and Gorman, J. A., Specifications for In-Situ Stress Relief of PWR Steam Generator Tube U-bends and Roll Transition, EPRI Report NP-4364-LD, Electric Power Research Institute, Palo Alto, CA, 1
December 1985.
4 4.7.6 Krupowicz, J. J., Scott, D. B., and Fink, G. C., " Corrosion Performance of
- Alternate Steam Generator Materials and Designs Vol. 2
- Post Test Examinations of a Seawater Faulted A.lternative Materials Model Steam Generator," EPRI-NP-3044, July 1983.
} 4.7.7 G. Santarini et al, Recent Corrosion Results - Alloy 690, EPRI Alloy 690 i Workshop, New Orleans, LA, April 12-14, 1989.
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4 FIGURE 4-1 EXPANSION / ROLL TRANSITION ZONE SLEEVE 4-10
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4-24
- 1 l S. SLEEVE EXAMINATION PROGRAM e
i During the installation process, the sleeves are examined using a combination of visual j ' 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 j in Figures 5-1 and 5-2, which are described below. ;
i !
l After the description of the inspection process,- the individual inspection methods will j be described in additional detail.
l After completion of the brush cleaning step, the first inspection is a VT process on j tubes to be sleeved to confirm adequate cleaning to proceed with the welding process.
i Parent tube cleanliness has been identified as a critical featute of the overall weldmg !
process. A VT after cleaning is performed with a miniature remote camera inserted I 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.
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 bond 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 l 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 splatter 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 to help resolve uncertainties in surface conditions detected by either the UT or ET inspections. If a 5-1
i 1
1 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 noncomformance 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 i portion of the weld are ident"ied for additional evaluation by the ET and UT I inspections. ;
1 1
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 inspection must be i performed after the heat treatment due to the possibility of additional signals from permeability variations caused by the heat treatment process. The entire length of the pressure boundary, including the pressure boundary portion of the parent tube inhind ,
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 a-e described in Section 5.2 and Figure 5-2 with the associated definitions in Table 5-1.
I i
l The sleeve to tube weld joints are 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. 1 The recordings are examined after the welding sequer.ce has been completed to verify that the essential parameters given in Reference I 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 ULTRASONIC INSPECTION 5.1.1 Sttm.marv 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 [ 15 ] MHz (physical construction of the probe will reduce the effective output frequency to [ 8- 12 ] 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 degree increments around 360 degrees with axial step increments of [ 0.020 ) inches; the scan path extends from above the weld so l 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 lotch representing a weld lack of fusion (LOF) region of [ 0.030 ] inch or greater. The ultrasonic signal is i
5-2
. ~ - -
1 lack of fusion (LOF) region of [ ] inch or greater. The ultrasonic signal is 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. l 5.1.2 Ultrasonic Evaluation The basis of the UT inspection is the detection of a reflective surface at the sleeve to i tube interface to detect a condition indicative of a lack of fusion. Sound is transmitted I from the sleeve inner surface through the weld to the tube outer surface. Although the )
reflection 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 fusion. j l
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 aoss sectional views of the ultrasonic reflectors are reviewed for evaluation of each wJd. Detection of a [ ] reflection is an indication of a complete weld.
In the absence of this signal, axial and circumferential cross sections (B and B' scans) I 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 i 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 Equioment 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 feedback for each axis
- 5. Calibration standard with machined notches for initial set up, as depicted in Figure 5-6.
4 5.2 EDDY CURRENT INSPECTION
, 5.2.1 Background 4
j 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 l, 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 has been performed. The description below discusses the most recent plus point probe design, which was extensively qualified for sleeve inspections in a program that exceeded the requirements of the EPRI Steam Generator Inspection Guidelines, Appendix H 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 H to add conservatism to the process.
The ET method is used to inspect the entire ;leeve region pressure boundary which has four distinct regions:
- 1) the sleeve between the upper weld and lower joint (either roll or weld,
, depending 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.
5-4
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< 5.2.2 Plus Point Probe Oualification Study i e
) 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 l* 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 H qualification
! report is provided in reference 5.4.3. The Appendix H qualification report provides l the details fer both the acquisition (ACTS) and analysis (ANTS) of the inspection data.
L Site specific analysis guidelines have been developed and analysts are trained and tested
- on the specifics of the technique. In summary, the plus point technique was demonstrated to be able to detect relevant flaw mechanisms 40% throughwall and greater in each of the regions identified above.
Particular attention was paid to the ATS weld region of the sleeve. The detailed process for the initial installation inspection is shown in the flow 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 I UT reviews mentioned in the flow chart. Either the standard + point probe or the magnetically biased style may be used for the inspection. 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 biased probe. !
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 be 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, WSI signals are resolved as blow holes outside or within the pressure boundary portion of the weld (BHA or BHB) or nondeleterious surface irregularities (WSS). If no surface condition is observed, then the signal is considered as a subsurface weld zone indication (WZI) 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 BHA (blow hole outside pressure boundary portion of the weld) condition is acceptable for service while the BHB (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 5-5
l l
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of the ATS weld on the sleeve outer surface. The oxide inclusion condition is j generally precluded by proper cleaning, which is verified usmg VT before installing the
' {
sleeve. Minor voids may occur in a small percentage of welds even with proper l
} cleaning, but generally are very shallow. No attempt is made to distinguish inclusions !
from voids, nor is there an attempt to measure depth or circumferential extent for these l-conditions. He 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 i ofindications relative to the pressure boundary portion of the weld was demonstrated in .
i the Appendix H qualification study and is reported in references 5.4.2 and 5.4.3.
i- l Various other anomalous conditions may be reported by the ET analyst that would i trigger an nonconformance report (NCR) and additional evaluation.
l The sleeve plugging criteria stated above provides at least a 9% margin with respect to i
growth and ECT uncertainity. His is cormintent with the minimum allowable sleeve j
thickness determined in Section 8.0, an appropriate growth factor for Alloy 690 (given i' its excellent corrosion resistance in primary and ==dvy environments), and the success rate in detecting indications of 40% or greater (Reference 5.4.3).
t j The other area of particular interest is the expansion transition zone above the weld.
] Here the parent tube constitutes the pressure boundary. The ability to detect 40%
through wall flaws was demanetawl using EDM notches and is detailed in reference l 5.4.3.
1 h 5.3 VISUAL INSPECTION i
4 j 5.3.1 Summary and Conclusions s
l 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 j
inspected for clantinas prior to sleeve installation. The second, optional inspection is j performed after completion of the ATS weld and is condm *M as a VT-1 inspection per j , 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 j- inspection is also performed for rewelds.
The VT is performed remotely by means of a miniature CCD camera inserted into the
- tube with the results recorded on video tape. Visual aids are provided for the 1
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.
i l
i 5-6 a
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J 5.3.2 Cleanine Inmaction l 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 d
inclusions. This process verification step is identified in the site specific traveller. 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.
5.3.3 Weld Enmination
?
1 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 '
! conditions reported in either the UT or ET results.
The CCD camera and right angle viewing mirror is inserted into the sleeve. The l
camera system is checked using a 1/32" black line on an 18% neutral gray card. Also, i 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 01-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 Enmination Guidelines Appendix H Qualification for Eddy Current Plus-Point ProbeExamination of ABB CENO Welded Sleeves", April 27,1996 (PROPRIETARY) 5-7
J TABLE 5-1 ACRONYMS USED IN ET ANALYSIS
- BHA: Blow Hole Outside Pressure Boundary BHB: Blow Hole Within Pressure Boundary
~
- i GEO
- Geometric signal LOF: Lack Of Fusion NCR: NonConformance Report i
NDD: No Detectable Degradation l PID: Positive ID retest RMB: Retest with Magnetically Biased probe i
UT: Ultrasonic Test VT-1: Visual Test, Type 1 per ASME Code,Section XI I 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 WZI: Weld Zone Indication-subsurface or indeterminant 5-8
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UT CALIBRATION STANDARD i
5-14
.s. . _ . . .. . - _ . . .
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- 6.
ELEEVE-TUBE CORROSION TEST PRO 3 RAM i
ABB-CE has conducted a number of bench and autoclave tests to evaluate the corrosion l 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 post-weld heat treatment. An outline of these tests is shown in Table 6-1. [As shown ,
l in the table some tests have been conducted with mill annealed Alloy 690 sleeves due
)
{ primarily to material availability. For the environnients being tested ABB-CE l
l considers these to be conservative tests in that thermally treated material has been
[ shown to perform as well or better than mill annealed material.]
i '
i 6.1-
SUMMARY
AND CONCLUSIONS l
l 6.2 TEST DESCRIPTION AND RESULTS 6.2.1 Primary Side Tests 4
4-w aem 6-1
TABLE 6-1
-. STEAM GENERATOR TUBE SLEEVE CORROSION TESTS s C
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, 6.2.1.1 Pure Water Stress Corrosion Crackine Tests %
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6-3
TABLE 6-2 Sleeve / Tube Caosule SCC Tests S_ amole Condition Failure No. Failure Time (Hrs) -
l
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6.2.1.3 TSP Sleeve Weld Capsule Tests l l
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6.2.2.2 Capsule Tests l I
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6-7
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w TABLE 6-3 SECONDARY SIDE STEAM GENERATOR TUBE SLEEVE CAPSULE TESTS ENVIRONMENT EXPOSURE TIME RESULTS A.
B.
C.
a a
D.
6.2.2.3 Sodium Hydroxide Fault Autoclave Tests .
e W
6-8
T
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4 6.2.2.4 Summary - Secondary Coolant Corrosion Performance 4
,+
I N 6-9
secondary fault environment. However, by the very nature of the weld joint in both an ETZ and TS sleeve, it must be located outside a region where fault species are capable of concentrating, ie. tube / support intersections. These environments would only exist in the area bridged by the sleeve and as such the structural integrity of the
. . tube / sleeve assembly would not be degraded.
6.3 REFERENCES
FOR SECTION 6.0 6.3.1 Statistical Analvsis of Steam Generator Tube Degradation, EPRI Report NP-7493, September 1991.
6.3.2 Summary Report, Combustion Engineering Steam Generator Tube Sleeve 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 Hydrogen Embrittlement ofIron Base Allovs, NACE, Houston, Texas, pp 1189-1204, 1977.
6.3.4 A. J. Sedriks, S. Foreen, and A. R. McIlree, "The Effect of Nickel Content on the Stress Corrosion Resistance of Fe-Cr-Ni in an Elevated Temperature Caustic Environment". Corrosion,Vol. 32, No. 4, pp 157-158, April .1976. i 6.3.5 F. W. Pement, I. L. W. Wilson and R. G. Aspden, " Stress Corrosion Cracking Studies of High Nickel Austenitic Alloys in Several High Temperature Aqueous Solutions." MaterialsPerformance, Vol.19, pp 43-49, April 1980.
6.3.6 P. Berge and J. R. Donati, " Materials Requirements for Pressurized Water
. Reactor Steam Generator Tubing." NuclearTechnoloev, Vol. 55, pp 88-104, October 1981.
, 6.3.7 G. P. Airey, A. R. Vaia and R. G. Aspden, "A Stress Corrosion Cracking Evaluation of Inconel 690 for Steam Generator Tubing Applications." Nuclear Technology, 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 Materials for Enerev Systems, Vol. 4, No. 3, pp 125-130, December 1982.
6-10
v 4
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FIGURE 6-1 PURE WATER CORROSION T ST SPECTMEN 6-11
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FIGURE 6-2 ATS WELD CAPSULE TEST SPECTMEN l
6-12
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FIGURE 6-3 TSP WELD CAPSULE TEST SP5CIMEN 6-13
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FlGURE 6-4 RTZ WELD CAPSULE TEST SPECIMEN 6-14
.- - .. - __ - . _ - _ . . - . -- . = . . -- - _ . _--
)
- 7. . MECHANICAL TESTS OF SLEEVED STEAM GENERATOR TUBES i 7.1
SUMMARY
AND CONCLUSIONS Mechanical tests were performed on mockup steam generator tubes containing sleeves l to provide qualified test data describing the basic properties of the conipieted assemblies. These tests determined axial load, collapse, burst and thermal cycling
- capability. A minimum of three tests of each type were performed.
i 1
4 i
7.2 CONDITIONS TESTED l
7.3 WELDED SLEEVE TEST PARAMETERS AND RESULTS 7.3.1 Axial Pull Tests b
7-1
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1 7.3.2 Collapse Testing i
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j 7.3.4 Load Cycling Tests !
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4 .a.,. - - . . .a4-J.44a J r e.e 44*4ab At 4 g22 mm- 4 A.-4_.4__a ,..m_-a-.4AsiJa---J4*-4L - -<M 4A J-.4.A,A-- M.2 .J..*_a A h-E .A > ..a &E,Asw a4 -e* -AE-a4 4_, a-.4A mt A Joe-saa---am wa--..aa. 3Ja..ae'W
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I 7-4
TABLE 7-1 SLEEVE-TUBE ASSEMBLY MECHANICAL TESTING RESULTS*
COMPONENT AND TEST RESULT (MAXIMUM) RESULT (MINIMUM)
N I 1
Welded Joint Axial Load Capability " l Upward Direction Downward Direction Rolled Joint Axial Load Capability No slippage Welded Joint Cyclic Loading i
Rolled Joint Cyclic Loading i
Sleeve Burst Pressure Sleeve Collapse l
~
- A minimum of three tests of each type were performed.
O 7-5
8.0 STRUCTURAL ANALYSIS OF SLEEVE-TUBE ASSEMBLY
.This analysis establishes the structural adequacy of the sleeve-tube assembly. The
. methodology used is in accordance with the ASME Boiler and Pressure Vessel Code, Section Ill. The' work was performed in accordance with 10CFR50 Appendix B and other applicable U.S. Nuclear Regulatory Commission requirements.
8.1
SUMMARY
AND CONCLUSIONS 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 Westinghouse operating 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 design requirements for tubing are covered by the specifications for the steam generator " vessel". The appropriate formula for calculating the minimum required tube or sleeve thickness is found in Paragraph NB-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.
t = 0.02S in. < t w = 0.030 in. (minimum sleeve thicimess) Reference 8.10 0
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) '
Sm= Design Stress Intensity, S.I. @ 650 F maximum design (per Reference 8.16) 8.1.2 Detailed Analysis Summarv When properly installed and welded within specified tolerances, the ETZ sleeve and its upper weld and lower rolled joint, and the TSP 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
-4 4 ,e .J...- ---- W+ '= m *e A 6-s 4.I*-5 J,.-e-J --
- 4a J GJ I
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l
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M emos i 8u
The evaluation of the TS upper and lower welds shows that the stresses and loads calculated
, for the ETZ upper weld are bounding. Physically, the upper and lower welds of the TS sleeve are a duplicate of the ETZ upper weld The ETZ sleeves at 26 inches are subjected to much higher loads than the shorter 9.0 inches or less TS sleeve, and therefore, the following analysis
,. -for the ETZ sleeves bounds the TS sleeves.
O 8-3
TABLE 8-1 i
SUMMARY
OF SLEEVE AND WELD ANALYSIS RESULTS
- The allowables listed in Table 8-1 are in accordance with the ASME Code (Refs. 8.1 and 8.16) 8-4
FORMULAS FOR GENERAL MEMBRANE STRESSES SUMMARIZED IN TABLE 8-1 i (Note: All SI equations below are a derivation of the formula in Par. NB-3324.1 of Ref. 8.1.) ;
i
, 1. GENERAL PRIMARY MEMBRANE STRESS (DESIGN TUBESHEET DELTA PRESSURE)
. l l l i -
- 2. MAIN STEAM LINE BREAK FOR ABB/CE PLANTS 1
__ l l
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3 FEEDWATER LINE BREAK FOR WESTINGHOUSE PLANTS N
~
- 4. PRIMARY PIPE BREAK (LOCA)
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8-5
TABLE 8 2
, SUl%BIARY OF ROLLED JOINT DESIGN, ANALYSIS AND TEST RESULTS l
I_ -.
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e 8-6
__ . _ _ _ _ . . .._ .. - - _ . ~ . . . _ _ _ _ _ _ _ . _ . _ . _ . . _ _ . - _ _ . .
i l 1, . .8.3.2 Postulated Pipe Rupture Accidents
! NRC Regulatory Guide 1.121 requires the following:
- e .."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),
- j. should be consistent with the margin of safety determined by the stress limits specified in NB-4
. '3225 of Section III of the ASME Boiler and Pressure Vessel Code".
- The above referenced ASME code paragraph deals with " faulted conditions", where for an elastic analysis of Inconel 690 sleeves, a general membrane stress of 0.7 So = 0.7(80.0) =
j 56.0 ksi is allowed. In conjunction with the NRC Regulatory Guide 1.121, the following 4
accidents are postulated:
i f
1 i-6 8-10
~ . . . __ _ _ . _ _ _ . _ . _ . . - __ _ . _ _ __ . .-. .._ ___ _ _ -_ __
I 8.2' LOADINGS CONSIDERED l
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 pper Tube Weld Pullout Load <
I j- 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.
i l
7 1
i ;
- i 4
- i I
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-. -.-. 1
- In the event of a main steam line break (MSLB) for an ABB/CE plant, the secondary pressure i 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:
- eminusim 8-7
J l s
8.2.2 Lower Sleeve Rolled Section Pushout Load I i
Assuming the parent tube is totally severed, the minimum load required to rupture 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 i !
condition (0% Power), the maximum available load would be: I
- l i
l 4
- I Note that the LOCA pipe break accident is not controlling for this joint. See Section 8.4.6.
8.2.3 Weld Fatigue l Since the factors of safety are quite high for loadings due to primary stress, the failure
- l. 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, whichjoin the sleeve to the tube will j 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 4
is addressed in Section 8.4.
i 8.3 EVALUATION FOR ALLOWABLE SLEEVE WALL DEGRADATION USING !
{ REGULATORY GUIDE L121 '
NRC Regulatory Guide 1.121 (Reference 8.3) requires that a minimum acceptable tube (or i sleeve) wall thickness be established to provide a basis for leaving a degraded tube in service.
j For partial thm-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.
{'
J 8.3.1 Normal Operation Safety Margins j It is the general intent of these requirements to maintain the same factors of safety in j
- evaluating degraded tubes as those which were contained in the original construction code, j ASME Boiler and Pressure Vessel Code,Section III (Reference 8.1).
l 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 1 of safety against failure by bursting under normal operating conditions of not less than 3 at l any tube location 8-8 1
1
. . _ - . -. -. -- - . . . . . - . - . . . . . . - ~ . . - . - - . - . . - . - . . . . . - . . . . . _
2
)
i
[ 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:
i Primary Pressure Pm = 2250 psi ;
- Secondary Pressure P= = 815 psi Differential Pressure AP = Ps- P= = 1435 psi j' Average Pressure P., = 0.5 (Pg + P=) = 1533 psi
i l
( I
- Assuming the parent tube is totally severed, the sleeve is required to carry the pressure '
- loading. The following terms are used in this evaluation.
i Ra = sleeve nominalinside radius J
i Syno = minimum required yield strength (per U.S. NRC Reg. Guide 1.121, Ref. 8.3)
! Sy = minimum yield strength of sleeve (Sy = 35.2 ksi min. at 650 *F, Ref. 8.16) 4 _
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8.3.3 Minimum Weld Height Requirement N
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g 8.4 EFFECTS OF TUBE LOCK-UP ON SLFF.VE LOADING
. Objective: Conservatively determine the maximum axial loads on the sleeve (tension and )
'L compression) during normal operation.
j .. _ General Assumptions: (See Figures 8-2 through 8-5). _
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! 8.4.1 Sleeved Tube in " Worst" Case ABB/CE Plant. Free at Egg Crate Support r
j - -
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l The sleeve loads, F2, are in Table 8-4A for the transient conditions shown in the same table.
8.4.2 Sleeved Tube in " Worst" Case Westinahouse Plant Free at Tube Support 6 _
e Oh 8-14
8.4.3 Sleeved Tube in " Worst" Case ABB/CE Plant. Lock-up at First Egg Crate Support i
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8.4.4 Sleeved Tube in " Worst" Case Westinghouse Plant, Lock-up at First Support h
8-15
> a *
- TABLE 8-3A 26 INCII SLEEVE AXIAL MEMBER PIIYSICAL PROPERTIES FOR " WORST" CASE ABB/CE PLANT -
~
NOTE: ' -
Nominal Dimensions for sleeve from Reference 8.10.
2 m and 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 Reference 8.15.
- a and E for Inconel 600 from Reference 8.13, Part D, Tables TM-4, TE-4.
5 m for Carbon Moly Steel from Reference 8.13, Part D. Table TE-1.
8-16
5 TAHLE 8-311 26 INCII SLEEVE AXIAL MEMBER PIIYSICAL PROPERTIES FOR " WORST" CASE WESTINGHOUSE PLANT .!
i 5
}
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- t NOTE: Nominal Dimensions for siceve from Reference 8.10. ~
2 m and 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 Reference 8.14. -
s and E for Inconel 600 from Reference 8.13, Part D Tables TM-4, TE-4. '
s for Carbon Moly Steel from Reference 8.13, Part D, Table TE-1.
8-17 '
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TAllLE 8-5A ,
AXIAL LOADS IN SLEEVE WITII tulle LOCKED INTO EGG CRATE SUPPORT FOR " WORST" CASE AllII/CE PLANT 3
- 1
- NOTE: Due to small variation, E and am value for normal operation,100% power are used.
8-20
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8.4.5 Effect of Tube Prestress Prior to Sleeving 1
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8.4.6 Lower Sleeve Rolled Section Pushout Due to Restrained Thermal Expansion l
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1 8.5 SLEEVED TUBE VIBRATION CONSIDERATIONS The vibration behavior is reviewed since the mstallation of a sleeve in a tube could affect :
. the dynamic response characteristics of the tube.
8.5.1 Effects ofIncreased Stiffness Stiffness and mass have opposing influences on tube vibration. While increased stiffness !
tends to raise the tube natural frequency, increased mass tends to lower it. ABB/CE's I 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 for the stiffer rod will be significantly less.
In addition, if any contet 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 i assembly is superior over the original tube, !
8.5.2 Effect of Severed Tube I i
1 1
4 8-23
-w,S' 4 4 E.i 4u ,--.
- r---+ra* - - - a 3------ - - - - - m. de r4 4 6 & d- E LAA.-m.- M d & -a& --- - L4a
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8.5.3 Seismic Evaluation i
The natural frequency of a sleeved tube for the span between the tubesheet and the _first tube
. suppott for the " worst" case situation is- ,
l 2
fa = (15.4/2x1) x (Elg/W/1) 5 = 38.0 HZ, (Reference 8.5)
. where: :
- f. = natural frequency, HZ i 1 = span length = 47.75 in. (maximum value in Reference 8.2) i 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.
g = 386 in/sec2 l 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 i on the vibration characteristics of the tubes. Test results indicate a natural frequency for a l completely severed tube somewhat below the healthy tube frequency, but above the seismic i cut-off frequency of 33 HZ. Hence, the seismic evaluation is performed for the static l equivalent load above 33 HZ. ,
i 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 ,
1 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:
Moss = 1/8 woetl2 = 53.8 in.-lb.
8-25
l l
Considering the sleeve cross section: '
Do = 0.625 in. I
, Di = 0.562 in.
I = 0.0026 in.'
C = Do/2 = 0.3125 in.
- i Stress s = M3sC/I = (53.8)(0.3125)/(0.0026) = 6.5 ksi < 1.5 S. = 39.9 ksi It is concluded that a seismic event produces a small stress in the tube sleeve. I 9
O e
- <spe 8-26
' 8.6 STRUCTURAL ANALYSIS FOR NORMAL OPERATION A static elastic analysis of the sleeved tube assembly was performed according to the
, requirements stipulated in NB-3220 Section E of the ASAG Code Section. Section 8.6.1 describes the methods used to analyze the upper tube weld.
8.6.1 Fatigue Evaluation of Upper Sleeverrube Weld
=
8-27
'N amassena e
9 4
4 enummmen 8-28
TABLE 8-6 o
UPPER SLEEVE WELD - TRANSIENTS CONSIDERED FOR AN ABB/CE PIANT 4
O mm.
3 a
8-29
TABLE 8-7 UPPER SLEEVE WELD - TRANSIENTS FOR A WESTINGHOUSE PLANT
-l l
e p
e 8-30
i I
1 8.6.2 Evaluation of Lower Sleeve Rolled Section 1
N 6
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4 1
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1 4
?
e 9
6-munu 8-31
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B _
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E D
I S _
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8 C .
E S _
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N A E T I S
N A
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I 3-8 T
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S
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R E
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TAllLE 8-9 LOWER SLEEVE SECTION - TRANSIENTS CONSIDERED FOR A WESTINGIIOUSE PLANT t
8-33
8.7 REFERENCES
FOR SECHON 8.0 8.1 ASME Boiler and Presmue Vcesei Code, Seccan III fbr Nuclear Power Plant Cui-=--- ,1989 eddinn i
l 8.2 ABWCE letter Report No. CSE-%116, " Tube Sleeve History Data for 3/4 inch Steam Gmerator i Tubes", May 07,1996.
j -
)
8.3 U.S. NRC Regulatory Guxie 1.121, " Bases for Pluggmg Degraded PWR Steam Generator Tubes".
- 8,4 ABB/CE imae Report CEN-624-P, Rev. 00, "Carchna Power & Light Shearon Hams Steam
, C m Tube Repair Using Leak Tght Sleeves", July 1995.
l 8.5 "Mechanni Vibratums", 4th FAtinn, by J.P. Hartog, McGraw4hil Book Co., New York, New i
York, pg. 432.
8.6 "Vibrabon in Nuclear Heat FvAS Due to Iipud and Two-Phase Flow," By WJ. Heilker and R.Q. Vincent, Journal of F% for Power, Vol.103, Pages 358-366, April 1981 (REF-%
015).
8.7 "ANSYS" Finite Elcancet C= =*~ Code, Rev. 5.1,1994, by Swanson Analysis Sys., Inc.
8.8 EPRI NP-1479, "Effect of Out<f-Plane Dehng inada on the Structural Integnty of Steam Generator hsernals," Coenractor: Che F.i- c.=u, August 1980.
8.9 ABB/CE License Report CEN-613-NP, Rev. 01, "Arnona Public Service Co. Palo Verde Steam Cwm Tube Repair Using Imk Tight Sleeves", January 1995.
8.10 ABB/CE Drawing No. D SGNS-222-001, Rev. 02, "RTZ Sleeve for 3/4" Diamder Steam C= Tubes".
8.11 ABB/CE Drawing No. D-SGNS-222-002, Rev. 04, "RTZ Sleeve Imtmilat=".
8.12 Inconel 690. M=*==tna Alloys, Inc., F=*= gena W. Virguna.
8.13 ASME Boiler and Pressure Vessel Code, br*= II, Matmals,1995 edrhon.
8.14 Weatmghm- Steam C-m Standard Infuu tiac Package, Jan. 04,1982 (REF-96-002).
. 8.15 ABB/CE Drawing No. E-234 622, Rev.1, " rube Dctails for SONGS II Steam Generator".
8.16 ASME Boikt and Pressure Vessel Code Case N-20-3, "SB-163 Nickel-Clumo.om-Irce Tubing (Alloys 600 and 690) . . at Specified Manmum Yield Stremsth of 40.0 ksi ..., Sechan III, Divison 1, Class 1", November 30,1988.
8.17 ABB/CE Report No. TR-ESE-178, Rev.1, "Pahawk Steam C m Tube / Sleeve Vibrabon Tests", October 05,1977 (REF-96-003).
8-34
1 l
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= .
l
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l 1
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6 i
0 FIGURE 8-1 '
WELDED STFF.VE/ TUBE ASSENH3LY 8-35
. 1 l
l l
1 l
l 1
l
= 1 1
i i
l FIGURE 8-2 SYSTEM SCHEMATIC FOR " WORST" CASE ABB/CE PL4hT
- m 8-36
l t
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FIGURE 8-3 SYSTEM SCHEMATIC FOR " WORST" CASE WESTINGHOUSE PLANT 4
8-37
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FIGURE 8-4
. STIFFNESS MODEL OF SLEEVE AND LOWIR TUBE 8-38
l l
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FIGURE 8-5 STIFFNESS MODEL OF UPPER TUBE AND SURROUNDING TUBES 8-39
_.J'4 M
emmene l
l 9
s 1
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4 6
FIGURE 8-f FINITE ELEMENT MODEL OF UPPER TUBE WELD 8-40
I i
1 9
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O O 3
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J b
APPENDIX 8A i
C FATIGUE EVALUATION OF UPPER SLEEVE / TUBE WELD N
8 8A-1
INTRODUCTION The analysis presented in this appendix is discussed in detail in Section 8.6.1 of this Report. The 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 [
] weld height model is based on the design geometry minimum dimension. The [ ] model is based on the minimum required axial weld length for operating and accident conditions. All stresses and usage factors for both configurations are e satisfactory when compared to allowables.
GENERAL DISCUSSION The Finite Element Method (FEM) was incorporated in this analysis, using the ANS'YS Computer Code (Reference 8.7). Figure 8-6 depicts the FEM model of the upper tube weld for both the ABB/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 assumed to be locked near the secondary side surface of the tubesheet. l From Section 8.4, it was found that the sleeve develops higher compressive loadings if the tube is free l 1
to slide through the first support . Therefore, sliding at the tube-to-support interface was conservatively assumed. The FEM model consists of 2-D isoparametric elements with an l axisymmetric option. The ANSYS input and output data are included in Attachment 1. i l
The axial loads are conservatively determined from a thermal interaction for a [ ] inch sleeve length using the equations in Section 8.4. These axial loads are applied to the bottom of the sleeve finite l
element model. The ABB-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% steady state pressure case stresses. These combined stresses are combined with the thermal case stresses resulting from the radial thermal expansion for the transients considered.
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 [ ] inches was determined in Section 8.3.3. A fatigue analysis was performed using a conservative weld height of [ ] inches. The finite element model used for the [ ] inch weld design was modified by refining the element mesh as shown in l Appendix 8A. For simplification purposes, the pressure stresses and stresses due to the radial thermal expansion were conservatively excluded. These pressure and thermal stresses result in tensile stresses which relieve the compressive stresses resulting from the axial loads.
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.
l
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'D j j
l l
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l 1
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11 6
FIGURE 8A-1 NODE AhT) STRESS CUT IDENTIFICATION 8A-3
l 1
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TABLE 8A-1A STRESS RESULTS 100% STEADY STATE I l
o :
l 6 1 l
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M me 8A-4
TABLE 8A-1B STRESS RESULTS 15% STEADY STATE b
I a
4 8A-5
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TABLE 8A-1C l l
s STRESS RESULTS 0% STEADY STATE I
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TABLE SA-1D i STRESS RESULTS FEEDWATER CYCLING j
4 I
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he 8A-7
TABLE 8A-2A RANGE OF STRESS AT WORST LOCATION e
S 4
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TABLE 8A-2B l I
o FATIGUE EVALUATION AT WORST LOCATION I m '
. 1 e
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b FIGURE 8 A-2 NODE AND STRESS CUT IDENTIFICATION FOR 20 MIL WELD 8A-10
TABLE SA-3A o
STRESS RESULTS 100% STEADY STATE (.02" Weld) b k
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TABLE 8A-3B
, STRESS RESULTS 15% STEADY STATE (.02" Weld)
OO q O
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9 4
TABLE 8A-3C
, STRESS RESULTS 0% STEADY STATE (.02" Weld) k l
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TABLE 8A-3D o
STRESS RESULTS FEEDWATER CYCLING (.02" Weld) 4 A
o TABLE 8A-4A
,,, RANGE OF STRESS AT WORST LOCATIONS (.02" Weld) s I
J k
e 4-8A-15
1 l
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v TABLE 8A-4B l
l FATIGUE EVALUATION AT WORST LOCATIONS (.02" Weld) l
=
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a
=#
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9 TABLE SA-4B (Cont'd) l l
FATIGUE EVALUATION AT WORST LOCATIONS (.02" Weld) l 1
l l
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e 6
b 1
APPENDIX 8B TUBE SLEEVE HISTORY DATA e
A ER D
- % EDEN ASEA SROWN SoVE A
% Inter-Office Correspondence !
To: W. R. Gahwiller May 07,1996 Soud ast Nuclear Service Center .
cc: D. P. Siska CSE 96-116 / Page 1 of 4 !
D. G. St-pnick l T. M. Taylor !
SUBJECT:
TUBE SLF. EVE HISTORY DATA FOR 3/4 INCH STEAM GENERATOR TUBES
REFERENCES:
(1) CEN-601-P Rev. 0-P Uc:nse Report, " Arbm Nuc!nr Oc: Unit 2 Stram G= rator Tube l Repair Using Leak Tight Sleeves", Jtme 1992. l (2) CR-9417-CSE92-1119-0 Report, " Evaluation of an ABB/CE Tube Sleeve br Application in Loth Power & Ught Seam Generators Waerford Unit 3", November 1992.
(3) CR-9417-CSE94-ll19-0 R.. port, " Evaluation of an ABB/CE Tube Sleeve for Application in l Maine Yanke: Steam Generatois", Sept:mber 1994 l (4) CR-9417-CSE93-1123-1 Report,
- Evaluation of an ABB/CE Tube Sleeve for Application in APS - Palo Verde Units 1,2, & 3 Seam Cc:ntors". Jam:aty 1995.
(5) CR-9419-CSE95 il19-0 Report, " Evaluation of an ABB/CE Tub: Sleeve for Application in B.G.&E. Calvert Cliffs Seam Generators", Sepember 1995.
(6) CENC-1272 & 1298 Reports " Analytical R: ports for Sou :m Califomia Edison San Onofr:
Units 2 & 3 Stam Generators". Sepember 1976 and Sepember 1977.
(7) CEN-368-P Rev. 0-P Lic=se Report, " Florida Pow:r & Light Co. St. Lucie Units 1 & 2 Seam Generator Tube Repair Using 1.:nk Tight Sle:ves", Febn:aty 1988.
(8) CEN-337-P Rev. 0-P Lic=se Report. "V. C. Su=m:r Stem Ge::rator Tube Repair Using Leak Tight Sleeves", August 1986.
(9) CEN-388-P Rev. 0-P Uc=se Report, Houston Power & Ught Soud Tens St:am Genentor Tube Repair Us=g Leak Tight Sleeves", April 1990.
(10) CEN-401-? Rev. 0-P Lic=se Report, Ringhals 3 & 4 Smm Generator Tube Repair Using Leak Tignt Sleeves" October 1990.
(11) CEN-600-P Rev.1-P Lic=se R:gort, "ASCO 1 & 2 Stem Gn=rator Tube Repair Using Leak Tight Sie:ves", Jt=e 1992. -
(12) CR-9417-CSE93-1115-0 Report " Evaluation of an ABB/CE Tube Sle:ve for Application in Krsko Seam Generators", June 1993.
(13) CR-9451-CSE95-1104-0 Report, " Evaluation of an ABB/CE Tube Sle:ve for Application in Co==o:: weald Edison Byron & Braidwood Units 1 & 2 Seam Ccerators", April 1995.
(14) CR-9451-CSE95-11114 Report, " Evaluation of an ABB/CE Tube Sleeve for Application in Carolina Pow:r & Light Sheaton Harris Steam Generators", July 1995.
Southeast Nuclear Service Cener (SNSC) reviewed de past tube sleev r: ports for 3/4 inch steam g:n=rator tubes.
R:ferenc:s 1 through 14 contain de Section 8 structural analysis as part of the lic=se r: ports. A review was also made of1 other 3/4 inch steam g=:rator tubes, prunarily, the Westinghouse D2/D3/D4 Scries steam generators to see if their parameters would produe: a " worst" cas: situation great:r dan those plants r: viewed in Ref:rences 1 through.14. Table 1 on pages 3 and 4 contain de nec:ssary parameters from the founeen references to develop a
~
" worst" ca'e envelopment situation for furder structural analysis of 3/4 inch rube sle:ves. Those " worst" case items for " operating" plants with inconel 600 st:2m generator tubes are not:d in Tab!: I wid an ascrisk (*).
CSE-96-116 / Page 2 of 4 For a "singl
- Westinghouse Plant smdy of all D2/D3/D4 steam generators wid Inconel 600 mbes (including dose plants not in de foun n- t:ferences), the ASCO 1 & 2 Plants (whose steam g=erators are being replaced with ones comaining Alloy 800 mbes) had de largest axiallead on the mbe sleeve. However, the next larBest axialload on the
, tube sI'efve is the CP&L Shearon Harns Plant which still has Inconel 600 mbes in me steam generator. This axial lead calculation is 939 lb. which is mainly due to the maximum differ:nce betwe:n the pnmary and secondary temperatures used in the strucnnal analysis (i.e. 93.5'F).
For a " single" ABB/CE Plant smdy of all the steam generators with Inconel 600 mbes (including those plants not in the fourteen references), the Waterford 3 and SONGS Plants vdll have the largest axial load on the mbe sleeve, primarily, due to the maxtmum difference between the primary and secondary t:mperatures in 1: peripheral tubes for the structural analysis being 105'F.
Sinc:r ly.
G. $ 2 B. A. Bell VERIFICATION STATUS: COMPLETE Th: Safety-R:!at:d design infot=2 tion cmd~d in mis dccu==t has been veriti:d to be correct by means of Design Review using Checklist in QP-3.4 of QPM-101.
Nam: _ ,I I). M m Signature ,18 [w Dat: C 94 In2:cend::t Reviev.:: L/ U BAB:bab e
8 e.
a e TAllLE 1: INCONEL 690 TUllF'SLEEVlf FOlt 3/4" DIAMETEll tulle CSE-El16 / Page 3 of 4 -
PARAMETER ANO 2'" Waterroid 3* Maine Yantec* . APS IlG&E . ~ 1 SONGS ,. . ' FP&l. SL 1.irie L Palo VerWM Calycil Clifff ' g, , ' t & 2m Tule Sleeve length / Report issue Date 42.25 /6-92 43.0*/l1-92 15.5*/9-94 40.0 /l-95 30.0"/9-95 not issued 40.0 /2-88 Design Tulx sheet Differential 2250* 2250* 2250* 2250 + 2250* 2250 * 'M50
- Pressure (psi) Use Max. .
Primary Pressure @ 100% Power (psi) 2250
- 2250* 2250* 2250
- 2250* 2250
- 2250*
Use Max.
Secoiulary Press. @ 100% Power (psi) 900 900 815
- 1070 850 900 815' Use Min.
Primary Temp. @ 100% Power (*F) 611 611 601.8 621.2 604 611 604 Seconda yTemp.@ 100% Power (*F) 532 (Sil") 532 (506 ") 520.3 (506 " ) 553 503" 532 (506 ") 520 (500 ")
Prim.-Sec. Temp. @l00% Power (*F) 79 (100) 79 (105*) 81.5 (95.8) 68.2 101 79 (105*) 84 (tal)
Use Max. Difference Primary Temperature @ XX% SS (*F) 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%) (15%)
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 Exngth between'lytxisheet & Ist 28.125 28.25 46.0 47.75 + 39.0 28.25 39.63/26.13 Support (in.) Use Max./ Min.
Seismic land Use Max. 0.35 g 0.33 g 0.I8 g 1.0 g 0.5g 2.25 g
Tulesheet 'Ihickness w/ Cladding (in.) 21.75 22.75 20.31 + 23.75 21.44 22.75 21.75 (l& 2)
Use Min.
Secondary Pressure During LOCA i100 1000 1000 1170 1000 1100 1000 Axial Load from Reference Iteport (ib.) 794 788 814 732 993 N/A 769
+
- Worst
- Case Envelopment Use Waterford 3 & SONGS Data for worst case Ailll/CE Plant study Use CP&I.Shearon llanis Data for worst case Westinghouse Plant study
- - Consideration for downcomer/feedwater sulrooling (l) Itererence (1) (2) Reference (2) (3) Reference (3) (4) Reference (4) (5) lieference (5)
(6) Iteference (6) (7) Reference (7) (16) ' Consideration for peiipheral tubes
, , . s-TAllLE 1: INCONRL 690 tulle SLEEVE FOlt 3/4" DIAMETEll tulle (cont'd) ^
CSE-%-116 / Page 4 of 4 PAllAMliTElt V.C. Sununei""' ilP&l South Itinghals 3 & 4"* ASCO i & 2(""' Krsla/2I .(Niy'ror$h ' Cl%L Shearon i D3- ~ D3 D3 D4- , Braidwrxx19 D4 Texad"__E2 . llatrif"2 D4 Tule Sleeve Length /Itclxnt Issue Date 40.0*/8-86 40.0*/4-90 43.0*/10-90 43.0*/5-92 17.5'/6-93 20.0*I4/95 20.0*n-95 Design Tulesheet DitTc'rential 1600 1600 1600 1600 1600 Pressure (psi) Use Max.
16b0 1600 Piimary Pressure @ 100% Power (psi) 2250* 2250* 2250* 2250* 2250* 2250* 2250*
Use Max.
Secorxlary Press. @ 100% Power (psi) %4 1100 877 987 920 925 %4 Use Min.
Primary Temp. @ 100% Power (*F) 619 626 613 620 617 618 620 Sec. Temp.** @ 100% Power (*F) 540 i
556 529 543 535 536 526.5 Prim.-Sec. Temp. @l00% Power (*F) 79 70 84 77 82 82 93.5 Use Max. Difference Primary Temperature @ XX% SS ("F) 567 576 567 567 567 567 567 -
(15%) (15%) (15%) (15%) (15%) (15%) (15%)
Secondary Temp. @ XX% SS (*F) 556 566 556 556 556 556 ' 548.5 (15%) (15%) (15%) (15%) (15%) (15%) (15%)
Prim.See. Temp @XX% SS (*F) li 10 1I Ii 11 11 18.5 Use Max. Ditference Prim. Temp. @ 0% SS (*F) Use Max. 557 567
- 557 557 557 557 557 Sec. Temp. @ 0% SS (*F) Use Max.
557 567* 557 557 557 557 557 j Feedwater Cycling (*F) 557/537 543/546 557/537 557/537 557/535 557/557 533/557 Span lengdi terween Tulesheet & lst 27.25 9.0
- 27.85 27.85 36.0 36.0 36.25 Support (in.) Use Max./ Min.
Seismic 12)ad Use Max. N/A N/A N/A N/A N/A 2.0 g (OIlE) 1.5 g (OBE)
Tubesheet 'niickness w/ Cladding (in.) 21.15 22.65 21.18 21.18 21.18 21.18 21.18 Use Min.
Secondary Pressure During IDCA 1092 1198
- 1092 1091 1091 1165 1170 Axial laxid from iteference Report (Ib.) 754 815 804 1208 818 830
_ 939
+
- Worst" Case Envelopment Use Waterford 3 & SONGS Data for worst case ADB/CE Plant study Use CP&I.Shearon liartis Data for worst case Westinghouse Plant samly
- - Consideration for downcomer/rcedwater subetxding (8) Iteference (8) (9) lleference (9) (10) lteference (10) Il1) Iteferrnen tl I) ti n ib.r..n.m nn
- 9. SLEEVE INSTALLATION VERIFICATION 9.1
SUMMARY
AND CONCLUSIONS
, The ABB-CENO 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 influence of tubes locked at tube supports, have been considered in as:essing 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 CENO steam 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:
4 9-1
9.2.2 Tube Sunnort Sleeve o 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:
9.3 WELD INTEGRITY 9.3.1 Cleaning Oualification A test program was conducted to establish the reduction of tube wall thickness after cleaning with the abrasive brush. Four oxidized tube samples were cleaned using a qualified brushing tool and process. It was determined that less than .0005 inches of metal was removed from each of the samples.
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 i
l l 9-2
component. However, after the tubing is brushed, the noise level returns to that of the baseline (pre-heat treat) data.
9.3.2 Exoansion 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).
9.3.3 Weld Oualification i
e 4
r 9-3
b 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 Oualification 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 pressure
, boundary portion of the tube expansion requires annealing to minimize residual stresses. The Electric Power Research Institute (EPRI) has documented (Reference 4.7.4 of Section 4.7) evidence in support of the annealing process. It was determined that a 3 to 5 minute soak time at a tube temperature of 1300 to 1425 F was required to maximize tube life.
9-4
t 9.3.5.1 Instrumented Analysis of Locked Tubes 1
s :.,
v 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 configuration is conservative when compared to a Westinghouse Series 44/51 steam generator. Four of the 9-5
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 v Support (TS) sleeves and a tubesheet sleeve were installed in each tube as shown in the figure. The tubes were instrumented 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 [
1 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 9-6
9.4 ROLLED JOINT INTEGRITY
, A development program was conducted to ensure the rolled joint of the ETZ sleeve 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. md V.T. has been removed from service due to service related degradation.
9.6 - REFEREINCES FOR SECTION 9.0 9.6.1 Tcst Report on Steam Generator Tube Cleaning for Installation of Welded Sleeves, PR-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
9.6.8 Qualification of the Post Weld Heat Treatment Tool for Westinghouse "D" Series Steam Generators,00000-ESE-830.
W 9.6.9 Qualification of the Roll Transition Zone (RTZ) Sleeve Rolled Joint,00000-ESE-826.
.9-8
TABLE 9-1 0.875 0.D. SLEEVED TUBE PWHT DATA e,-
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TABLE 9-2
,. 0.750" O.D. SLEEVED TUBE PWHT DATA TUBES LOCKED AT ALL SUPPORTS s
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TABLE 9-3 ABB CENO S/G SLEEVE OPERATING HISTORY 9 ---
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FIGURE 9-2 0.875 0.D. LOCKED TUBE TEST i
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4 FIGURE 9-3 0.875 0.D. LOCKED TUBE TEST TEMPERATURE AND AXIAL LOAD PROFILE 9-14
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FIGURE 9-5 0.750 0.D. TYPICAL TEMPERATURE PROFILES
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10.0 EFFECT OF SLEEVING ON OPERATION Multiple plant specific analyses have been performed to determine 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 t the head and flow characteristics of the pumps, in conjunction with the primary system hydraulic resistances, system flow rates have been calculated as a function of the 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 newly 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 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 q primary to secondary heat transfer in the region where the sleeve is installed. The loss
,, j in heat transfer area associated with sleeving is small when compared to the overall length of the tube.
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In summary, installation of sleeves does not substantially affect the primary system flew rate or the heat transfer capability of the steam generators.
x 10-1
J TABLE 10-1 TYPICAL SLEEVE TO PLUG EQUIVALENCY RATIO 4
1 CASE CONFIGURATION 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.
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APPENDIX A l
PROCESS AND WELD OPERATOR QUALIFICATIONS A.1 SLEEVE WELDING AND SLEEVE WELDER QUALIFICATION 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.
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A-1
_ _ _ _ _ _ _ _ _ - - --A
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