ML20199A623
| ML20199A623 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 10/31/1997 |
| From: | ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY |
| To: | |
| Shared Package | |
| ML19313D074 | List: |
| References | |
| CEN-620-NP, CEN-620-NP-R04, CEN-620-NP-R4, NUDOCS 9711180040 | |
| Download: ML20199A623 (91) | |
Text
-. _ _ _.
9 ATTACHMENT 3 l
Combustion Engineering, Inc.
l Report CEN420 NP Revision 04 NP Series 44 & 51 Design Steam Generator Tube Repair Using a Tube Re Rolling Technique October 1997 Non Proprietary i
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l PROMt!ETARY Df0RMATION COMBUSTION ENGINEERING,INC.
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This docwnent contains proprietary information ar4 is i
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ret to be transmitted or reproduced without spect6c winen 9 proval from Combustion Engineering, Inc.
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Revision 04 NP
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i October 1997 g..,
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Series 44 & 51 Deeisa l
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Steam Generator Tubs Rrp.ait
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Unine A Tube Rerolling Technigut
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J FINAL REPORT
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AbD Combustion Engineering Nuclear Operations Windsor, Connecticut
. '.:eb LEGAL NOTICE THIS REPORT WAS PREPARED AS AN ACCOUNT OF WORK SPONSORED BY m
ABB COMBUSTION F'4GINEERING.
NEITHER ABB COMBUSTION i
ENGINEERING NOR ANY PERSON ACTINO ON ITS BEHALF:
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MAKES ANY WARRAN1Y OR REPRESENTATION, EXPRESS OR IMPLIED INCLUDING THE WARRANTIES OF FITNESS FOR A PARTICULAR i
PURPOSE OR MERCHANTABILITY, WITH RESPECT TO THE ACCURACY.
COMPLETENESS, OR USEFULNESS OF THE INFORMATION CONTAINED
- ..gl 4 IN THIS REPORT, OR DIAT HIE USE OF ANY INFORMATION, APPARATUS, METIlOD, OR PROCESS DISCLOSED IN THIS REPORT MAY NOT INFRINGE PRIVATELY OWNED RIGHTS; OR 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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ABSTRACT l
A technique is presented for repairing degraded mesm generator tubes in Weninghouse pressurirrd water reactors with Series 44 and 51 design mesm generators. He technique j
alleviates the need for plugging or sleeving those Weam generator tubes with defects in the
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tubesheet region.
innead of traditional repair techniques (plugging and sleeving), the degraded tubes will be i
rerolled above the original tubenheet hard soll to form a new leaktight joint above the inhial-4 tubesheet roll transition rene, nis technique will re emablish the pressure boundary between the -
i primary and secondary side symems and provide the necessary mmetucal capability for operational and upset conditions.
j nis report details analyses and teming performed to verify the adequacy of the roll transition l
rone reroll process for retuming nuclear steam generator tube 5 back to service, it demonstrates that terolling tubes, with defects in the tubesheet region, is an acceptable repair technique.
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IABLE OF CONTENTS SM*ica Ihlt East l
ABSTRACT lii
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1.0 INTRODUCTION
11 i
1.1 Pu. pose 11
1.2 Background
1-1
[
2.0 QUALIFICATION CRITERIA 21 2.1 Technical SpeelGcating 2-1 2.2 Acceptance Criteria 21 3.0
SUMMARY
31 4
4.0 REFERENCES
41 5.0 DESIGN DESCRIPTION OF kEROLL AND 51 INSTALLATION EQUIPMENT L
5.1 Reroll hint Deni==
5-1 i
I 5.2 Renair Of A Defective Rerolled Tube 5-2 5.3
&croll Joint lasa"ation Equ'pment 5-2 5.4 ALARA ConMemlama 5-4 6.0 TEST PROGRAM 61 6.1 -
Isst. Matrix 61 6.2 Tests Reautred On Coumons 62 iY e
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TABLE OF CONTENTS (Continued)
SEllen Ihlt East
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7.0 TEST RESULTS 7.I 7,1 Coupon Preparation 7-1 7.2 Igique Development 7-3 7.3 Igit Procedurc 7-4 7.4 l%ese 1 - F* Compon Readts 77 7.5 1%1ge 1 - EF* Coupsn Results 79 7.6 Phase 2 - Additional F* And EF* Coupon Results 7-10 7.7 Tube Growth _Issts 7-12 7.8 Rollgtij{g 7 12 7.9 Discussion-7 13 8.0 STRUCTURAL CONSIDERATIONS 8-1 8.1 Reroll Joint Configuration 8-1 8.2 Plug And Sleeve Pronram Applicability 3-24 8.3 Rgfgtgggg g.26 9.0 EDDY CURRENT EXAMINATION 9-1 9.1 justallation VerificatiQa.
9-1 02 Rotatina Probe Eumination 9-1 10.0 EFFECT OF REROLLING ON OPERATION 10-1 y
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i LIST OF TABLES l
lahit_NA Iille PAge l
31 F* RerollTem Matrix 33 i
32 EF* Ret 011 Test Matrix 3-4 33 Additional F* And EF* Reroll Ten Matrix 35 71 F* Torque Development 73 72 EF* Torque Development
- 7. 4 -
73 F* Mechanical Ten Results 7 16 7-4 F* 11ydrostatic Test Results 7-17 75 EF* Mechanical Test Results 7-18 7-6 EF* Hydrostatic Test Resuks 7 19 l
7-7 Additional F* And EF* Resoll Mechanical Ten Resuhs 7.20 78 Additional F* And EF* Hydrostatic Test Results 7 22
~
81 Axial Member Physical Propenies. Westinghouse Series "44" 8-6 First Reroll Joint Location Case with Tube Lock up i
8-2 Axial Member Physical Propenies Westinghouse Series "51" 87 First Reroll Joint Location Case with Tube Lock up 8-3 Axial Loads in Locked Tube Westinghouse Series "44" 8-8 Fira RerollJoint Location Case 8-4 Axial Loads in Locked Tube - Westinghouse Series "$1" 8-9 First Reroll Joint Location Case l 8-5 Axial Member Physical Propenies Westinghouse Series "44" 8-13
,. Second Reroll Joint Location Case with Tube Lock up 8 Axial Member Physical Propenies-Westinghosse Series "$1" 8-14 Second Reroll Joint Location Case with Tube Lock-up r
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i LIST OF TABLES (continued) 87 Axial Loads in Locked Tube Westinghouse Series "44" 8 15 Second Reroll Joint Location Case 38 Axial Loads in Locked Tube Westinghouse Series "$1" 8 16 Second Reroll Joint Location Case E9 Axial Member Properties Westinghouse Series "44" and "51" 8-19 First Rerolled Joint Location Case without Tube Lock up 8-10 Axial Loads in Non Locked Tube Westinghouse Series"44" 8 20 and "$1" for the First Rerolled Joint Location Case 8-11 Axial Member Physical Properties-Westinghouse Series "44" 8 22 and "$1" fbr the Second P,eroll Joint Location Case 1 12 Axial Loads m Non Locked Tube - Westinghouse Series"4 r' 8 23 and "$1" for the Second Rerolled Joint Location Case 8-13 Tubesheet Ligament Stresses for Westinghouse Series "44" 8-25 and "$1" Steam Generators at Design Conditions vii
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LIST OF FIGURES Firure No.
Iitle East 51 Reroll Joint Configuration 56 P
52 Remote Control Manipulator 57 t
53 Rotation Station And Controls 58 I
' 5-4 3 rushing Tool 58 55 Ilydraulic Expansion Equipment 59 56 Rolling Tool 59 7I Typical Expansion Trace 7 24 72 Typical Torque Trace - Wet Sludge Sample 7 25 73 Typical Torque Trace - Dry Sludge Sample 7 26 81 Rerolled Tube Model And Environment 83 82 Tube Schematic - Series "44" Steam Generators for 84 First Reroll Joint Location Case 83 Tube Schematic - Series "$1" Steam Generators for 8-5 First Reroll Joint Location Case 8-4 Tube Schematic - Series "44" Steam Generators for 8.1 Second Reroll Joint Locatica Case 85 Tube Schematic Series "51" Steam Generators for 8-12 Second Ret 011 Joint Location Case
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1.0 INTRODUCTION
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I,1 Purnose 4
De purpose of this repon is to preside information sufficient to back licensed F* and EF*
analyses in suppon of a 10CFR50.59 safety evaluation allowing installation of rerolljoints in
_ Weninghouse-designed Series 44 and 51 steam generators with degraded tubes in the tubesheet region. His repon demonstrates that reactor operation with a tube rerolljoint in l
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 1
different kind of accident and will not reduce the existing margin of safety.
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ABB Combustion Engineering Nuclear Operations (ABB CENO) provides two types ofleak limiting rerolljoints for Westinghouse Series 44 and 51 steam generator tube repair. De first joint type can be located anywhere in the [
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- t He steam generator tube with the reroll joints meets the structural requirements of tubes which are not degraded.
Design criteria for the reroll joints were prepared to ensuie that all design and licensing requirements are considered. Analyses and testing have been performed on the tube reroll joints to demonstrate that the design criteria are met.
De effect of terolljoints on steam generator heat removal capnoility and system flow rate are discussed in Section 10 of this repon.
After the reroll joints are installed, an examination is performed using eddy current (ET)
- techniques. De ET examination serves as a method to verify that the rerolljoint was l I in the steam generator tube and to assure that F* and EF* criteria of undegraded hard roll tube length above previous indications are met by the reroll process.
Plugs or sleeves will be installed if the reroll procedure is not successful or if there is unacceptable degradation of steam generator tubes due to the process, k
1.2 - 1)fskaround he operation of Pressurized Water Reactor (PWR) steam generators has, in some instances, resulted in localized corrosive attack at the roll transition zone region and in the tubesheet -
crevice region of the steam generator tubing; his corrosive attack resuhs in a localized reduction in stenm generator tube wall thickness, Steam generator tubing has been desigr.ed i
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with considera' ole margin between the actual wall thickness and the wall thickara.: coqui.ed to meet miuctural requirements. Dus it has not been necessary to take corrective action unless l
uructural limits are being' approached.
Himorically, the corrective' action taken where mesm generator tube wall degradation has been severe has been to inmall plugs at the inlet and outlet of the steam generator tube when l
the reluction in wall thickness reached a calculated value referred to as a plugging criteria.
i An additional repair option has been to bridge the defect utilizing a sleeve. Eddy current (ET) examination has been used to measure mese generator tube degradation and-the tube plugging criteria accounts for ET measurement uncertainty.
Installation of steam generator tube plugs removes the best transfer surface of the plugged 1
tube Dom service and leads to a reduction in the piimary coolant flow rate available for core cootag. Installation of steam generator sleeves does not signiScantly affect the heat transfer l
removal capability of the tube being sleeved and a large number of sleeves can be installed without significantly affe: ting primary flow rate. However, there is a ednor reduction in flow rate associated with large numbers of sleeves and potential accessibility concess as well.
He use of a tube reroll process will alleviate these concerns as well as leave the tube in a condition to perform repairs at a later time.
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1 2.0 QUALIFICATION CRITERIA t
2.1 Technical Specification
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Westinghouse Series 44 and 51 Steam Generators 2.1.1 Design and Operating Ratings j
Primary Operating / Design Temperature:
61l'F./ 650T Primary Operating / Design Pressure:
'5 psig / 2485 psig Secondary Operating / Design Temperature:
517T / 550T
. Secondary Operating / Design Pressure:
653 psig /1085 paig 2.1.2 Steam Generator Tube Data Tube 11 ole Drilling (min./nux.):
.888/.893 in.
Tube Nominal O. D.:
.875'.
m Tube NominalWall:
.050 in.
Tube Wall noduction Due to Rolling:
4-6%
2.2 Accentance Critada
%e following acceptance criteria were used to asser.s the performance of rerolled jo!.nt coupon specimens during testing.
2.2,1
%e established torque va'.ues shall yield a l
] percent tub wall reduction.- Rese values were chosen as a means of bounding the original equipment manufacturing speci6 cations. Als range of values reflects ABB's experience in plug and sleeve rolling in steam generator tubes. Also, the larger range accommodates % uncertainties associated with remote field applications.
2.2.2 -
De rerolled tubejoint shall exhibit no movement relative to the tubesheet during l
simulation of cyclic loading conditions.
2,2.3 ne rerolled tubejoint shall exhibit no movement relative to the tubesheet at push and/or pull test forces which represent the maximum load experienced by the tube under operating or accideat conditions with the tube unrestrained at the support i
plates. Rese loads are [
], for rerolljoints both above and below the neutral axis of the tubesheet.
De loads associated with a tube in the restrained condition are leu than these values.
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De rerolled tube joint shall exhibit leak rates that can be used to determine the
- number of rerolljoints that can be installed per plant technical specifications when.
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- subjected to secondary side pressure levels equal th three times the operating or upset condition pressure differential. Section 7.0 defines the basis for the test -
pressure selection.
2.2.5 ne roller expander shall produce consistent rolls of bright metal surface finish.
There shall be no measurable signs of wear which could effect the rolled joint over the proposed (
) life of the roller expander, assuming a planned lubrication interval of fifty rolling operations.
- 2.2.6 Non-destructive examination techniques shall be utilized to verify that the hydraulic expan 'an (where applicable) and rerolljoint were [
] and that F* and Elevated F* (EF*) criteria ofunder,raded hard roll tube length above previous indications are met by the reroi: process.
2.2,7 The tube rerolljoint shall not adversely affect system flow rate or heat transf:r capability of the steam generator tube.
2-2
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i 3.0
SUMMARY
l A total of[
] coupons consisting of[
] for F* and EF* qmlification were subjected to a rigorous qualification program. He program was performed in two phases; the first phase is shown in Tables 3-1 and 3-2, and the second phase is shown in Table 3-3.
He program was designed to test variables and off-nominal conditions that could be experienced during held operations. Rese variables included the expected range of tube hole diameters, rolling torques and variaV.e ceditions in the tute to
- tubesheet annulus. Such conditions include the presence of slu ge in ho% wet form and dry, compacted form. The [
_ j effective length roll expander ffvr rr.oll jdnts below the c
tubesheet neutral axis) and the [' ] effective length roll expander (tu rerolljoints above the tubesheet neutral axis) were used to prepare all test coupons. He complete test matrices are i
included as Tables 3-1 through 3 3.
i Torque values associated with a [
] percent tube wall reduction were established using production equipment. The minimum torque value [
] used in the test program yielded a [three] percent tube. wall reduction, and the maximum torque value [
] used in the test program yielded a [
] percent tube wall reduction.
He nominal value was established at [
- l. He tooling and control systems used in the test programs represent the present technology for reroll production equipment.
As technological advances are made, the updated equipment may be utilized upon completion oflaboratom verification.
The Phase I samples in Tables 3-1 and 3-2 were mechanically cycled at a load range of [
], then hydrostatically tested. He Phase 2 reroll samples were thermally cycled at a temperature range of [
] and were mechanically cycled at a load range of[
), then hydrostatically testea. The addition of the thermal cycling for Phase 2 was intenden to add a level of conservatism to the program. Rese samples were used to determine the effect on the rolled
.,: int of conditions in the steam generators, such as; the range of tube hole diameters, range of m'dng torques and variable conditions in the tube to tubesheet annulus. He resuhs of these t.;ts revealed no joint slippage and minimal leak rates. These leak rates can be used to determine the number of tubes that can be rerolled per the plant technical specifications.
The samples were hydrostatically tested at three pressure levels from the primary and secondary side. Rese pressures were [
] psi for Phase I and ['
l psi for Phase 2. He samples were held for a period of time ranging from five minutes to twenty-four hours for the normal operating differential pressure and for thirty minutes for the accident conditions and monitored for leakage. The clean F' and EF* test cases were leaktight at all primary side pressures, while the contaminated samples from Zion and Prairie Island showed minimalleskage at the these test pressures. He dry sludge samples exhibited minimalleakage during the secondary side test. He details of these test results are discussed in Section 7. Samples were push or pull tened, depending on which phase. of the program was being performed. He push test samples were loaded to a predetermined load of
. l
] while the pull test samples were loaded to failure.
3-1
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. Sanples_which had been rerolled were sectioned and revealed a bright, smooth surface after completion of the rolling' operation. Here were no indications of degradation of the tube due to the reroll process.
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Table 3-1
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1 Phase 1 - F* Reroll Test Matrix l
l sgf,'< y,;pi4" TESTS lpgpd@ i.
CASE VARIABLES NO OF TUBE HOLE CYCLE PUSH HYDRO COUPONS r;.
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1 2
3 4
5 6
7 8
9 Note I: Test roller expanders at intervals of 50,100 and 200.
3-3
Table 3-2 Phase 1 - EF* Reroll Test Matrix 7"* s <,TESTSggw '>f CASE VARIABLES NO.OF TUBE HOLE CYCLE PUSH HYDRO COUPONS
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4 5
6
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Table 3-3 Phase 2 - Additional F* And EF* Reroll Test Matrix t
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@MR $45M413STSs@hdef' 1 P CASE V RIABLES ROLL SMPLS Cr Cu PULL He Hs tp s m.
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5 6
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Cr - THERMAL CYCLE He - PRIMARY HYDROSTATIC f
Cu - MECIIANICAL CYCLE Hs - SECONDARY HYDROSTATIC ALL COUPON HOLE SIZES TO BE.893" AND ALL ROLLING TORQUES TO BE SET AT MINIMUM VALUES
' TESTS TO BE PERFORMED @ ~528'F 3-5
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4.0 REFERENCES
4.1 Nuclear Power Business Nuclear Quality Assurance Manual, QAM 100, Founh' Edition, Revision 4.
l 4.2 Quality Assurance Procedures Manual, QPM 101, Revision 0, i
4.3 - Quality Plan No. 2004396-QP-94-014, Rev. 00, " Project Quality Plan for the Development
- and Qualification of a Tube Re Roll Process for Westinghouse Steam Generator Tubes."
]
4.4 STD-400-153, Rev.00, " Test Plan for the Development and Qualification of. a Steam i
Generator Tube Re-Roll Process for Westinghouse Series "44" and "51" Steam Generators."
4.5 00000-OSW 007 Rev. 00, " Test Procedure for the Development and Qualification of a Steam Generator Tube Re-Roll Process for Westinghouse Series "44" and "$1" Steam Generators."
4.6 Project Plan No. PP 2006735, Rev. 01, " Project Plan for Additional Reroll Quali6 cation Testing" 4.7 00000-OSW 019, Rev. 00, " Test Procedure for the Additional Development and Qualification OfA Steam Generator Tube Reroll Repair Process" 4.8 Telecopy to Dave Stepnick of ABB-CE from Richard Pearson of Nonhern States Power, dated December 21,1994. Design Input on F-Star /L-Star Plugging Criteria.
4.9 TR-ESE 887, Rev,00," Test Repon for the Qualification of the Roll Transition Zone Sleeve Rolled Joint for Westinghouse "D' Series Steam Generators."
4.10 CENC 1599, " Qualification Testing of Combustion Engineering Mechanical Tube Plug with Addendum A."
4.11 Test Report No. WO-94-205, ' Test Report for the Additional Development and Verification of the Transition Zone Sleeve Rolled Joint for 3/4" Steam Generator Tubes."
4.12 Drawing No. C-SGN 217-458, Rev 04, " Reroll Joint Configuration."
4.13 Qualification Report, GBRA 014 020, " Steam Generator Tube Repair by Tube Reexpansion."
(ABB Reaktor) 4.14 "Doel 2 - Tube Reexpansion, ABB Conclusions about July Demonstration," 08/13/90. (ABB
{
Reaktor) 4.15 " Repair of SG Tubes by Rerolled Expansion - Corrosion Test."(Laborelec Labs) -
4.16 ; Memo No. PENG-95-015, ' Testing of Steam Generator Tubesheet Reroll Samples," A. B.
Goulet to E. P. Kurdziel, dated January 23,1995.
7 4-1
4.17 Memo No. WO96186, " Test Results for Re Roll Qualification Program," D. G. Stepnick to E. P. Kurdziel, dated October i I,1996.
4.18 00000-OSW 010, Rev 00," Test Procedure For The Life Testing Of Roll Expanders."
4.19 TR-400 002, Rev. 00," Test Repon For The Life Testing Of Roll Expanders With Decreased Lubrication Frequency."
4.20 Repon No. A-ABBCE 9419-il19, Revision 00, " Evaluation of Tube Re-Rolling for Westinghouse Series 44 & 51 Steam Generators."
4.21 Specification No. 00000 OSW 009, Rev. 00, " Design Specification for Re-Rolled Joints in Steam Generator Tubes."
4.22 Telecopy to Dave Stepnick of ABB-CE from Richard Pearson of Nonhern States Power, dated September 1,1996. Design loput on EF Star /L-Star Plugging Criteria.
4.23 Memo No. 96177.DS, " Continuation Of Reroll Qualification Test Program," D. Stepnick to E. Pohl, dated Octobert,1996.
4.24 Memo from D. Proctor to D. G. Stepnick, " Top Of Tubesheet Reroll Collapse Test," dated September 19,1996.
4.25 Memo No. PENG-96-496, " Testing of Steam Generator Tubesheet Reroll Samples," A. B.
Goulet to Dane Proctor, dated December 4,1996.
4.26 Repon No. MISC-PENG-TR-106, " Load Cycle and Axial Load Testing of Reroll Samples,"
dated October 10,1997.
4.27 Repon No. 97-TR FSW-021, " Test Repon On Additional Reroll Qualification Testing,"
dated October 10,1097.
4-2
i
- 5.0 DESIGN DESCRIPTION OF REROLL JOINT AND INSTAILATION EQUIPMENT l
5.1 Reroll Joint Desa Reference 4.21 contains requirements for the reroll joint and its installation. He joint i
becomes the [
].
De reroll joint design is based upon the technology previously developed at ABB. Included in this category is the experici.ce of ABB Reaktor in the areas of [
], and the experience of ABB Combustion Engineering in the areas of[
]. ABB has installed over
[
] using rolling technology and over [
] using similar technology.
He reroll joint geometry is shown in the drawing presented in Figure 5-1. Muhiple reroll joints may be used in a tube. He critical parameters conceming the joint geometry were developed by the original equipment manufacturer using F* and EF' analyses. Based on these analyses, it was determined that up to [
] In addition,it was determined that up to [
]upon completion of the reroll would meet EF' criteria. Per the analyses, [
1 Based upon information provided by utility personnel who owned and operated Series 44 and 51 steam generators, ABB-CE determined that the original hard rolllength in steam generator tubes ranged from a minimum of one and one halfinches to a maximum of two and three quarter inches. Based upon this information, ABB-CE decided to [
] from the steam generator tube end _ nis joint is put in place using a [
]. His geometry places the bottom edge of the reroll joint a [
] from the maximum height of the original roll transition.
As part of the rerolljoint, a hydraulic expansion may be performed prior to the hard roll process step. His hydraulic expansion utilizes current steam generator sleeving technology.
ne hydraulic expansion consists of a [
] from the tube end and extending past the hard rolliegion. His process step serves a number of purposes; first, to remove any unexpanded region between the original and new hard rolls;'second, to provide a gradual transition from expanded to unexpanded tube above the reroll joint; and third, to minimize the amount of crevice products between the tube and tubesheet upon process completion.
. Through the use of process control, the tube wall reduction from the hard roll will be limited from [
] percent minimum to [
] percent maximum. His range of wall reduction 5 '
. ~.
i ensures an acceptable reroll joint under the variety of conditions tested under this program.-
Als range of roll expansions is consistent with the resuhs of previous studies performed by
- ABB on sleeve and plug rolling, as well as industry experience demonstrating this range to provide optimum structural integrity for hard rolled joints 5.2 Repair Of A Defective Rerolled Tube
-If a tube is found to have an unacceptable rerolled joint, the tube can be rerolled muhiple times above the first reroll. De reroll may be performed as long as there is adequate tube length available. When multiple rerolljoints are unacceptable or not possible, the tube can be l
sleeved in order to keep it in-senice or it can be taken out of senice with standard
- mechanical tube plugs at both ends of the tube. In either case, approved methodslo perform the processes are in place.
5.3 Esroll Joint Installation Equipment ne equipment used for the remote installation of rerolled joints in a steam generator is made up of the following basic systems:
- 1. Remote Controlled Manipulator
- 2. Rotation Station
- 3. Tube Brushing / Cleaning Equipment
- 4. Tube Expansion Equipment
- 5. Tube Rolling Equipment
- 6. Tube Eddy Current Equipment Hese systems, when used together, allow installation of the rerolljoints without entering the steam generator. In this way, personnel exposure to radiation is held to a minimum.
He tooling and methods described in the fcllowing sections represent the present technology for rerolled joint installation. As technological advances are made in the installation process, the updated techniques 'may be utilized upon completion oflaboratory verification by ABB-CE. '
5.3.1
. Remote Controlled Manipulator
- The remote controlled manipulator (Figure 5-2) serves as a transport vehicle for repair and inspection inside a steam generator hot leg or cold leg plenum.
The manipulator consists of two major components; the manipulator leg and the manipulator arm. He manipulator leg is innalled between the tubesheet and the -
bottom of the primary head and provides axial (vertical) movement of the arm.
5-2
t i
The manipulator arm is divided into the head arm, probe arm and swivel arm.
- Each arm is. moved independently with. encoder position controlled electric motors. He swivel arm allows motion for tool' alignment in various types of tube
^
pitches. _ Computer control of the manipulator allows the operator to move tools from outside the manway and accurately position them under the proper tube -
against the tubesheet ~.
5.3.2
' Rotation Station He rotation station (Figure 5 3) mounts on the end of the manipulator arm through the use of a locking dovetail arrangement. De rotation station delivers l
the various tools required for the reroll operation to the proper location'. Cameras mounted on the rotation station are used to verify location as well as aid in the entry of tools into the tube. Proper elevations for the various tools are obtained through the_ use of hardstops. The rotation station also provides controlled rotation to some of the tools used in the reroll operation.
He station is controlled through the use of a torque monitoring system, which trips the station off when the preset torque value is reached.
5.3.3 Tube Brushing / Cleaning Equipment
%e initial step in the reroll process involves cleaning the tube inside surface with a stainless steel wire brush (Figure 5-4), or equivalent. The purpose of this step is to remove the majority of the tube surface contamination that forms during power plant operation. The removal of this material allows for efficient operation -
of the rolling tool, as the working of the tube is transferred to the control station as torque, with no foreign materialintroduced into the rolling pins that could lead to toci inefficiencies. Additionally, the removal of the oxide layer will aid in roller lifb. An air motor rotates the brush tool as it is inserted into the end of the tube. At the appropriate elevation, the tool is reciprocated over the reroll area a total of one time. An interference fit between the tube and the brush assures a clean surface upon completion of this process step.
5.3.4 Tube Expansion Equipment For F* reroll joints, the hydraulic expansion equipment (Figure 5 5) is used to minimize the amount of crevice products between the tube and tubesheet prior to hard rolling the steam generator tube. He expansion tool consists of a mandrel and. a bladder that contains demineralized water which is - used as the pressurization f'uld. _ When the hydraulic expansion tool is pressurized, the bladder acts directly against the inside surface of the tube causing expansion of the tube. A tool hardstop is provided for proper tool vertical positioning.
He hydraulic expansion unit contains a pressure transducer which is set to the proper pressure setting prior to use. The pressure transducer signalis fed back to the display screen's strip chart recorder in order to record the pressure reached during the expansion cycle.
5. - -
~
A An _ expansion pressure -is utilized to : ove the tube _ into _ contact with the tubesheet and move debris trapped between the tube and tubesheet away from the area. His hydraulic expansion does not add to the structural integrity of the joint and no credit is taken during analysis of the joint.
He hydraulic expansion may be used with any of the reroll joints (Figure 51).
liowever, due to equipment reachability and tube access concerns, it is typically 6
used only on the lower two reroll elevations.
5.3.5 Tube Rolling Equipment The tube rolling equipment (Figure 5-6)is used to expand the. tube into intimate contact with the tubesheet, forming a structurally adequate leak limiting joint; ne rolling tool is positioned under the proper tube using the manipulator, which is then used to insert the toolinto the tube. De rolling tool utilizes a hardmop to position it vertically in the proper location.
He rolling equipment consists of the air motor, tube expander, torque readout and torque calibration unit. The torque readout and settings of the rolling tool are verified on the torque calibration unit prior to rolling of the tube. He tube is expanded to a torque which has been demonstrated by testing to provide a leaktight joint. He torque trace appears oc the display screen's strip chart recorder and is used for evaluation of the rolling process on the individual tubes.
The torque trace is used as the official record of the process. A second roll is performed to verify the torque level reached on the first teroll. The evaluation of the torque trace is the basis for acceptance or rejection of the rerolljoint since the joint integrity is based on percent wall thinning. A rolled joint which fails to meet the acceptance criteria may be rerolled. This is done by repeating the process at an elevation above the first reroll.
5.3.6 Tube Eddy Current Equipment After the reroll joints are installed, an examination is performed using eddy current (ET) techniques. He ET examination serves as s method to verify that the rerolljoint was l l in the steam generator tube and to assure that F* and EF* cliteria of undegraded hard roll tube length above previous indications are met by the reroll process.
'~
5.4 = ALARA Considerations i
ne steam generator repair operation is designed to minimize personnel exposure during re-roll operations. The manipulator is installed from the manway without entering the steam generat'or. It is operated remotely from a control station outside the containment building.
He positioning accuracy _of the manipulator is such that it can be remotely positioned without having to install templates in the steam generator.
5-4 i
_. _ _ _ - _ _ _.~
. _. _. _ _. ~. -..
De rotation station is d signed so that the dovetail fitting quickly attaches to the manipulator.
The rotation station la designed to quickly engage the individual rerolling tools. He tools are
. simple in design and all operations are perfonned 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 tubes rather than perfonning es.ch tool operation on the same tube before proceeding to the next tube. His < educes the number of tool changes which are required, if tool repair is necessaiy. the too!is removed and reroll operations continue using a spare 001. Tool repair is completed off the platform in a low radiation area.
. Air, water and electrical supply knes for tooling are designed and maintained so that they do
~
not be:ome entalyled during operation. - His minimires personnel exposure on the steam generator platform. All equipment is operated from outside the containment building.
In summary, the steam generator operation is designed to minimize personnel exposure to ionizing radiation and is in full compliance with ALARA standards.-
4 i
5-5
I 1
Figure 51 4
Reroll Joint Configuration 5-6
-r-
- 4.
7 i
=4 4
4
.e T
4 i-i 4
)
Figure 5-2
' Remote Control Manipulator 5-7
Figure 5-3 Rotation Station And Controls Figure 5-4 Brusidng Tool 5-8
_.. ~ - _ _ _.._ -.
g q
I 4 :
b T
v I
-?
i Figure 5-5 Hydraulic Expansion Equipment k
' Figure 5-6 Tube Roll Expander 5-9
n t
j
^
B 6.0 L TEST PROGRAM 6.1 Iest Mattis -
Dree test matrices were developed to test the rerolljoint over a range of test conditions.-
nese matrices are shown in Tables 31 through 3 3. The matricos represent a range of-conditions to which the rerolled joint was tested A total of l-l coupons were-tested for each test case fur the program. A ' description of each of the test conditions and type of tests is given below.
6.1.1
- Tube Dimensions Various heats ofInconel 600 tubing were used in this program. The material was purchased from Sandvik Steel Co. and from Valinox Nucleaire. He tubing was purchased to nominal dimension of.875" O.D, x.050" wall, however, the tube wall dimensions were not uniform, varying from-a minimum of.047" _to a maximum of.051" This was accounted for in the measurement sep of sample preparation.
6.1.2 Tube Hole Size Changes in diameter affect the amount of wall thinning the tube will experience and require that the roller expander perform consistently over a range. A range.
of tube hole sizes was tened in the reroll program. His range of hole sizes represents actual tubesheet drill hole sizes per the original equipment manufacturer's specification.
He_ hole sizes tested were the l 1
6.1.3 Surface Finish The tube holes for this program were bored to produce a surface finish of l l
RMS. The tubes were purchased to a [ ] RMS outside diameter surface finish-and were received with a-l l RMS finish. These variables were constant throughout the test program.
6.1.4 Torque Setting A minimum and maximum torque setting was developed as part of this program.
As described earlier, these settings are defined as the torque required to produce approximately l l percent tube wall thinning. Test cases in the F*
program performed the reroll using a 1 l percent wall thinning. Test Cases in the EF* program also performed the reroll using l l percent wall thinning.
v 6-1
c 6.1.5
- Studge Conditions De probability exists that sludge will be present in the annulus between the tube and tubesheet _ duting rerolling operations. Sludge in both the wet and dry condition was introduced into the annulus prior to performing the reroll. A l -
l for the wet sludge test cases. -
b l was performed, his extra-preparation step assured a 1-j.
He sludge formulation was based upon sludge analysis performed by'['
l.
1 6.1.6 Roller Expander Rolles expander geometryis a constant with the essential variables being the cage l
diameter, slot dimensions, helix angle, roll dimensions and taper of the internal mandrel. His roller expander geometry is based upon experience gained in plug and sleeve installation programs. He [
] effective length roll expander was used w prepare all test coupons for the F* program, while the [ ] effective length roll expander was used to prepare all test coupons for the EF* program.
6.1.7 Effective Roll Length l
In addition to the two roll lengths investigated per the previous section, samples were prepared with an effective length of 1.00". His length is just shon of the F* length of 1.03" and 1.07" applicable to Prairie Island and Zion respectively, his set of teus was perfonned in order to verify the adequacy of the minimum F* distance which was calculated in the F* analysis.
6.2 Tests Required On Counons For the drst phase of the program, the test procedure requires a hydrostatic leak test after reroiling the tube into tl'e block. - Upon comp!:. tion of the hydromatic leak test, the coupons were subjected to cyclic loading tests, aRer which the coupons were hydrostatically leak tested a second time. He by-!rostatic leak tests were performed from the secondary side in order to increase the conservatism of the test. A primcry side hydrostatic leak test was also performed in order to conform to the requirements of Reg. Guide 1.121. Finally, the coupons were subjected to a push test to determine tiae load atwhichjoint movement occurs.
For the second phase of the program, some of the test variables were changed. He coupons were prepared with minimum torque values and maximum hole sizes.' His was.'done to ensure a conservst ve test. He samples were then thermally cycled l i
J. Upon completion of the thermal cycling, the coupons were sub)cted to 6-2
cyclic loading tems, after which the coupons were hydrostatically leak tested. The hydrogatic -
leak tests were performed from the primary and secondary sides. De primary side hydrostatic leak test was also perfonned in order to conform to the requirements of Reg. Guide 1.121.
Finally, the coupons were subjected to a pull tests to determine the load st which joint movement occurs.
W h
).
6-3
-ww w-
7.0 : TEST RESULTS 7.1 CRM29n.frenaration
- Mock tubesheets were machined with dWerent size tube holes as defined in the test matrix.
Additionally, a split block wi*h a nominal hole aize was machined, his block was used to -
develop the torque range required to meet the acceptance criteria.
[
7.1.1 Tu'oe lastallatimi 9 team generator tubes were cut to six inch lengths and rolled into the tubesheet blocks at the lower end of the blocks. His was done to anchor the' tube in the block and to simulate the original hard roll. If the particular coupons required suhe conditions, the sludge was brushed onta both the tube outcide surface and the tube hole 'nside surface prior to locking the tube in place. Measurements quired for tube wall reduction calculations were taken prior to installing the
'6e into the block.
4 7.1.2 Tube Urushing He tube inside surfaces were brushed using a stainless steel wire brush. He coupons were placed in a test stand and the rotation station was used to perform
- he brushing operation. He brush tool was reciprocated over the length of the tube one time to complete the cleaning operation.
7.1.3 Tube Expansion Where applicable, the tubes were expanded into the blocks using the hydraulic expansion equipment described earlier. The bladder length used for coupon preparation was [
). He use of a [
] for Phase I testing does not detrimentally affect the test results in any way. An [
j was used to expand the tube into the block. Here was no effect ou tube expansion due to various pressure settings. A typical expansion trace, as recorded on the strip chart,is shown in Figure 7-1.
7.1.4 Tube Rerolling J
The rerolling operation was performed by fixturing the wupon into a rolling stand. The [
] roll expander was used for all F* rerolli.ig tests and the [ ]
roll expander was used for all EF* tests. He test matrix defined the torque levels that were required for coupon preparation. A typical torque trace, as recorded on the strip chart (torque is along the Y-axis, while time is along the X-axis), is i
showi in Figure 7-2 for a coupon prepared with wet sludge. He wet sludge is easily pushed from behind the tube and there is a smooth, steady increase in torque.
7-1
- A typical torque trace, as recorded on the strip chait, is shown in Figure 7-3 for a
- coupon prepared with dry, hard sludge. The dry, hard sludge is fragmented and moved about during the rolling operation, 'Ite torque setpoint is reached over a longer period of time.-
7.1.5 Coupon Numbering
'Ihe following numbering system was used to identify the coupons.
Phase 1 - F* Pronram B1,B2,B3 Case 1
[
]
A1,A2 A3 Case 2
[
]
A4,AS,A6 Case 3
[
]
Cl,C2,C3 Case 4
[
J C4,C5,C6 Case 5
[
]
Dl,D2,D3 Case 7
[
]
El,E2,E3 Cas: 8
[
]
F1,F2,F3 Case 9
[
]
Phace 1 - EF* Program i10 3 Case 1
[
]
90-4 Case 2
[
]
140-3 Case 3
[
]
90-5' Case 4
[
]
110-4 Case 5
[
]
130-1,130-2 Case 6
[
]
Phase 2 - Additional F* And EF* Reroll Pronram Il-1 through 11-5 Case la
[_
]
12-1 through 12-5 Case Ib
[
]
21-1 through 21-5 Case 2a
[
]
22-I through 22-5 Case 2b
[
]
31-1 through 31-5 Case 3a
[
]
32-1 through 32-5 Case 3b -
[
]
4-1 through 4-3 Case 4
[
]
5-1 through 5-3 Case 5
[
] 1 through 6-3 Case 6
[
]
7-1 through 7-6 Case 7 -
[
]
8-1 through 8-6 Case 8
[
]
9-1 through 8-3 Case 9
]
]
10-1 through 10-6 Case 10 '
[
]
7-2
[
1, --
t 7.2 Torque Developmal L
The first step in the program was to develop torque levels associated with tube wall thinning ofl
- 1 percent. His was done by using the split block arrangement. Tubes were -
placed in the split block, rolled,' hen measured to determine wall thinning. Tables 71 and 7 2 give the values for the various torques using the l -
) effective length roit for the F*
. program and the l
-) effective length ioll for the EF* program.
(
Based upon this information, maximum and minimum torque values were first chosen for the l
l e fective length rolls. Rese values were !
] for the minimum torque 8
setpoint, [
] for the nominal torque setpoint and I j for the maximum torque setpoint. Dese were the torque settings that were utilized during the testing process.
I Additionally, a test coupon was rolled to the system limited (based on supply air) torque value ofl
- l. His sample, with a wall thinning ofl _
1, successfully passed cyclic, push and hydrostatic testing.
Table 7 Fa Data Torque (in lbs)
Wall ninnina (%)
Torque (in lbs)
Wall ninnine (%)
N Wummuu t
6 7-3
TaNe 7 EF* Data Toroue (in-lbs)
Wall Dinning (%)
Toraue (in lbs)
Wall Dinning (%)
7.3 Test Procedure References 4.5 and 4.7 are the detailed procedures describing all step-by-step actisity for the test program. This section summarizes the procedure used to conduct de various tests on the coupons. Tables 7-3 through 7-5, at the end of this section, summarize all of the test resuks.
7.3.1 Rennal Cycling Tests The additional reroll samples prepared for phase two of this program were thermally cycled between [
- 1. His was done to simulate the heatup and cooldown cycles that a power plant experiences.
7.3.2 Mechanical Cycling Tests Normal operating and postulated accident conditions resuk in cyclical axial and flexure loading conditions on the steam generator tube and tubesheet, He maximum tubesheet loadings result from a flexure pattern where tubesheet ligament stress across the majority of the tubesheet is tensile above the neutral axis and compressive below the neutral axis. For reroll joints below the neutral axis, the compressive stress would tend to close the tubesheet hole during operating conditions, thus increasing the tube to tubesheet joint contact pressure.
For rerolljoints above the neutral axis, the tensile stress could open the tubesheet hole during operating conditions, thus potential]y reducing the tube to tubesheet joint contact pressure.- An extensive test and qualification program on the Roll Transition Zone Sleeve rolledjoint (Reference 4.9), has shown that the tubesheet -
flexure has no effect on dejoint structural integrity or leak tightness. Therefore, only axial loads were applied to test coupons during the reroll joint cyclic test program.
7-4
_. ~ - -
4
- He rerolled joints were subjected to a cyclic axial load test to demons: rate structural capability of the joint. De loads used for the cyclic tests were based -
upon the operating loads experienced by a tube in a unlocked condition, as this was the worst case loading condition on the tubes. Rese loads are [
]. Section.8 provides an analysis of this conditio2.
De loading was applied to these rerolled joints using an MTS Testing Machine.
I 1
Ehase 1 - P And EP Tests All coupons prepared for P Cases 1 through 5 were [
. ]. The rerolled joints for F* test Case 9 were conservatively loaded between [
] for a total of [
]
cycles. Coupons prepared for EP Cases 1 through 3 were i 1.!
]. Rese samples were used to determine the effect on the rolled joint due to conditions expected in the steam generators, such as; the 1
1 l
Ehase 2 - Additional P And EP Reroll Tests All coupons tested for the additional reroll testing program were {
l.I 1
7.3.3 Push And Pull Tests Phase 1 - F* And EP Tests As described in the previous section, steam generator tubes are subjected to loading conditions while in operation. He maximutu bads to which the tube is subjected are [
2
]. He rerolled coupons were push tested to a load of(
l for -
the P coupons and [
] for the EP coupons using an MTS Testing Machine. Coupons from P Cases I through 5 and EP Cases 1 through 3 exhibited [
] at this load and the test was terminated. Coupons from P Cases 7 and 9 were pushed to failure. He failure occurred due to tube buckling at a load of[
];the rerolledjoint did not [
l.
7-5
t-t g.
[
- Phase 2 - AdMa==1 F* And EF* Reroll Tests For the additional reroll test program, the sangles were pulled to failure, it _was
' decided that pulling the samples represented a more conservative approach.than
' the push test.1%e reroll joints failed at a minimum load of [
j _The
. maximum failure load wss [.-
]_
7.3.4 Hydrostatic Leak Tests Phase 1 F* And EF* Tsas Hydrostatic leak tests were performed on the coupons before and'aAer cyclic testing. The tests were performed from the secondary side in order to increase.
the conservatism of the test. He test was performed at [
J. %e first pressure level represents the operating pressure differential.
He ASME Code hydrostatic test pressure of!
1.25 x Primary Design Pressure = 1.25 x 2485 psi = 3106 psi is the basis for the second test pressure. For added conservatism, ABB-CE increased the pressure another [
] for the third test pressure.
All samples except the samples [
] exhibited leaktightness.
Samples Cl,C2 and C3 had an [
1 In order to comply with the guidelines of Regulatory Guide 1.121, which call for a test pressure of three times the operating differential, F* Test Case 7 coupons were pressurized to [
] fh,m the primary side. [
1 Phase 2 - Additional F
- And EF* Reroll Tests -
De same approach as above was taken with the additional reroll tests which were performed. Some samples were tested from the primary side and others from the secondary side, per the test matrix. The pressures at which the samples were tested was raised slightly and the hold times were increased, leading to a more conservative test condition. : He first pressure was [
- ), followed by [
), then [
]. All of the clean samples tested from the primary side exlulited leak tightness, while the samples tested from the secondary side exlu%ited varying degrees ofleakage, ranging from a low of [-
l.
7-6
7.3.5
- Collapse Tens De possibility exists that sludge will be present in the annulus between the tube and tubesheet during rerolling operations. De moimure in wet sludge, trapped between two rerolled joints, has the potential of flashing to steam under operating--
temperatures. He pressure build up during this event will be released either through the rolled jomts or by a cellapse of the tube. Test coupons containing i
1 7.4 Phase 1 F* Coupon Resuhs Test Case 1 - [
]
- Counons B1,B2 and B3 of this test case successfully passed all phases of testing.
l 1
Test Case 2 - [
]
Coupons Al, A2 and A3 of this test case successfully passed all phases of testing.
I 1
Test Case 3 - [
]
Coupons A4, A5 and A6 of this test case successfully passed all phases of testing.
I 1
Test Case 4 - [
]
Coupons Cl, C2 and C3 of this test case successfully passed all phase of testing.
I 1
7-7
\\
^
Test Case 5 - [
]
Coupons C4, C5 and C6 of this test case successfully passed all phases of testing.
I l.
Test Case 6 - [
]
l See Section 7.7 for the resuhs of the {
l test.
Test Case 7 - [
]
Coupons Dl, D2 and D3 of this test case successfully passed the push tests and the primary side hydrostatic leak test.
I 1
Test Case 8 - l
]
I 1
I 1
I 1
-Test Case 9 - [
]
Coupons F1, F2 and F3 ofthis test case successfully passed all phases of testing.
I 1
7-8
0 7.5 Liase 1 EF' Counon Resuhs Test Case 1 - l l
l Coupon 110 3 of this tem case successfully passed all phases of testing.
l I
i l.
Test Case 2 -l l
1 Coupon 90 4 of this test case successfully passed all phases of testing.
l 1
Test Case 3 - l l
Ct upon 140 3 of this test case successfully passed all phases of testing.
I 1
Test Case 4 - l l
Coupon 90 5 of this test case successfully passed all phases of testing.
I 1
Test Case 5 -l l
Coupon 110-4 of this test cat,:.accessfully passed all phases of testing.
1-1 Ter: Case 6 - lNwthmt Tube Hole (890) - Collapse Test)
+
1 1
7-9
f l
1 i
7.6 Phase 2 Additioni F* And EF* Coupon Re=hs Test Case la - l l
Coupons 11 1 through 11 5 successfully passed all phases of testing.
1 I
Test Case Ib - l l
Coupons 12-1 through 12 5 successfully passed all phases of testing.
i 1
Test Case 2s - l 1
Coupons 21 1 through 21 5 successfully passed all phases of testing.
t I
Test Case 2b - l 1
Coupons 22 1 through 22 5 successfully passed all phases of testing.
I 1
'l Test Case 3a - l l
Coupons 31-1 through 31-5 successfuhy passed all phases of testing.
7-10
e 1
l y
Test Case 3b - [
]
Coepous 32 1 through 32 f. successfully passed all phases of testing.
1 t
1 Test Case 4 - l
]
Coupons 4 1 through 4 3 successfully passed all phases of testing.
I 1
Test Case 5 - [
]
Coupons 5 1 through 5 3 successfully passed all phases of testing.
I I
Test Case 6 - l l
l Coupons 6-1 through 6 3 successfully passed all phases of testing.
I I
Test Case 7 - l l
i Caupons 7 1 through 7-6 successfully passed all phases of testing.
.. l 1
7-11
4 Test Case 8 - [
]
[
Coupons 81 through 8-6 successfully passed all phases of testing.
j l
4 Test Case 9. [
]
Coupons 9 1 through 9-3 successfully passed all phases of testing.
[
l Test Case 10. [
]
1 Coupons 10-1 through 10 3 successfully passed all phases of testing.
i
-I I
7.7 Tube Growth Tests An additional area of concern was the area of steam generator tube growth or contraction during the rerolling operation. Lee coupons were prepared and measured prior to the rerolling operation. The samples were then hydraulically expanded over a length of three and one halfinches a length which represents the amount of unrolled tube that will be expanded in the steam generators. The coupons were then subject to a torque that resuhed in [
]
percent wah thinning. He resuhs are shown below.
Tube N. laillal1 math Exnansion Lanoth Reroll Lanoth Change Q
~l-6.060"
[
}
[
]
[
]
2 6.06s"
[
]
[
]
[
l 3
6.069"
[
]
[
]
[
j De change in ler.gth due to the hydraulic expansion was on average [
] and the length change due to the reroll was on average [
], for an overall length change of, on average,
-[
]..
7 12
- ~ ~. _ _ _ _. _. _. _. _ _ _ _ _ _ _ _ _ _ _ _ _. _ _ _. _ _ _.
l I
7.8 Roller Life l
ABB CE has a large volume of experience with rolling operations. References 4.16 and 4.17 l
document life testing performed on roller expanders during sleeve roll qualification testing.
l His data is applicable to the current program, since similar roller designs are employed and similar materials are involved. In both of the referenced programs, there was no [
j N
7 1
4 1
i 7."
Digussion f
Torque values associated with tube wall thinning of [
l were l
established using production rolling equipment. %ese values were established by rolling tube j
samples in a split block and recording the torque trace. He tubes were then removed from the block, sectioned and measured to determine wall thinning. Based upon the acceptan_ce criteria established, which bracketed criginal equipment manufacturing criteria and reflected ABB CE rolling experience, torque values for the [
] and [ ] cffective length rollers in the range ofl
] were established.
F* And EF* Tests Using the torque values established, the tests called out in the test matrices were performed.
All samples were pmated using a production control system and tooling. All [
]
coupons, representing various steam generator conditions, were tested and met the acceptance criteria. De low torque coupon (Al A3) preparation resuhed in torques above the minimum value ofl
- j. His occurred due to an overshoot of the intended value by the system. liowever, it still resuhed in a low wall thinning value of approximately
[
l percent, Cyclic load ranges of[
] and [
] were used to test both the F* and EF* coupons for a total of[
). He load values were based on the worst case loading that the tube would experience (depending upon location in the tubesheet) and
- cycling-the tube throt.gh the totalc amount of load cycles the tube experiences during operation, regardless of loading conditions.
His approach assures a high degree of conservatism. Under these loading conditions, [
1 A push test load ofl
] was applied to all of the rerolijoint coupons. His value represents a load greater than the maximum tube loading conditions described earlier. De terts were stopped _before joint failure was observed. [
]. As an additional test, six coupons were pushed to failure. Failure occurred by tube buckling at [
l.
7-13 l
_ __. _ _ _.. _... _. _ _ _. _ - ~
Hydrostatic leak tems were performed on all coupons before and aRer cyclic loading. De test pressures represented a secondary side hydromatic test and a primary side hydrostatic test All tems were performed from the secondary side of the coupons, which represents a high degree of conservatism. He ASME Code hydrostatic tem pressure ofl
- l. An additional [
' ) was then applied to increase the factor of safety hnber. l l coupons were tested from the primary side at a pressure ofl J. This represents a pressure greater than the three times operating differential presrure set fonh b Rgulatory Guide 1.121.
j All coupons held pressure for n [
] minimum at each pressure level with no observable leakage except for the coupons with [
1 Dese coupons exhibited an l
- 1. I t
j.
I 1
6dditionalF* And EF' RerollTests He test samples were prepared according to the test matrix shown in Table 3 3. All coupons were prepared with a low torque trip point and large hole diameter (.893") in order to increase the conservatism of the test. All of these samples were [
1 All'of the samples were also mechanically cycled froan [
1 Under these loading conditions, [
1 Hydrostatic leak tems were performed on all coupons aAer cyclic loading. De test pressures represented a secondary side hydrostatic test and a primary side hydrostatic test. Tests were performed from the primary and secondary side of the coupons. De test pressures were i
1 his latter value represents a pressure greater than the three times operating differential pressure set forth in Regulatory Guide 1.121.
i 7 14
i i
All of the clean coupons coupons tened from the primary side held pressure with no observable leakage, while the tubes from Zion and Prairic Island exiu%hed [
[
r e
i
). The coupons tened from the secondary side showed low levels ofleakage. Wee coupons exiu%ked an i i
i I-A f
- I i
i r
4 L
e i'
7 15 I
i o
.7 hts s ue PT
-e gl et lc se CyT no i
Htac u
WdeR s
t l
u seR I
I o D.
ts RI 3 e 7-T 6
1 el l
a 7
b ci a n Tahce ge M
nuq i
l l
r F
oo RT e r l
e ot Hem S a
/iTD n r g e
opb l
2 3
4 S
6 1
2 3
l 2
34 S
6 1
2 3
1 3
um 7
A A A A A A B B B C C CC C C D D D F F
ou CN g
i
i t
~
t r
sei s Tp o0 r2 d1 y4 e
H d
isyra m
irp mor f
t s
s d
t ei u
Tp w
s l
n s
e o5 o
R r2 f
d1 r
y3 e
ts l
p e
I T
3 4
D k
7-a l
7 e
eL D
1 l
b 7
c t
ai p
Tt e
a c
t x
so e
r t
e, s
d ei d
s y
Tp i
H s
o0 y
r0 r
F d 0 a
y2 dn H
oces mor f
d n
e mr o
frep n r s
e t
o s
b e
p 2
3 4
5 6
1 2
3 1
2 3
4 S
6 1
2 3
1 l
2 3
um A A A A A A B B B C C C C C C D D D F F
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= = 1 op I
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Table 7-6 EF* Hydrostatic LeakTest Results Compen Hydro Test Hydre Test Hydre Test Number 2000 psi 3125 psi 4120 poi
- ,
- m a
--. :p.
p;.
a m_;
y
- m. y g.
.cg,;-.g( y _
90-3 90-4 90-5 110-3 110-4 140-3 I
l Note: Moisture on coupon 90-5; no measurable leak rate t
1 I
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5 Figure 71 Typical Expansion Trace 7 24
, - - - ' ^ ^ -
.nm
-. ~
)
4 S
(
Figure 7 2 T picalTorque Trace.WW Sludge Sa@
3 7 25
d I
Figure 7 3 Typical Torque Trace Dry Sludge Sample 7-26
STRUCTURAL CONSIDERATIONS 8.0 An analysis was perfonned to generate conserv f Main Steam tube 1101 locked at the first support plate during the f ll d only pressure differential since the loading due to d
locked in the first support plate are evaluated.
He operating and design conditions for all of th cf the Series 44 and 51 steam generators are und in the analysis. T (2) terolled joint location cases. In the first es inches from the secondary face of the tubesheer for the Series 44 and In the second case the rerolled joint is 2 inches f stmetural evaluation for the rerolled tube geometry is modeled in Figure 81.
8.1 M193110intf91tflgnall9n 8.1.1 Axial Loading for the First Rerolled Joint Case with Tube Lock up The rerolled tube schematics for both the Westinghouse Series 44 and 51 s generators are shown in Figures 8 2 and 8 3, res tubesheet for the Series 44 and 51 tmits, respectively, ne stmetural modelis f
of axial members with properties and boundaries as shown in Tables 81 an Series 44 and 51 steam generators, respectively. De material properties of clasticity and mean coefIicient of thermal expansion) come from Refer The axialload on the rerolled tube is due to the thennal expansion between and 11. No axialloading due to pressure exists between Points A and 11 A and 11 are externally balanced.
From Figure 81, the tube at Point A is locked in the first tube support ab tubesheet and is therefore, forced to move with the sunounding seconda axial load, F, is a function of the spring constants for the lower and upper between Points A and II, the location of the rerolled tube joint in the tubes forced displacement between the tube and shelUtubesheet arrangeme A and B. The thermal growth of the lower tube, upper tube, shell, and tu represented by 6, and the equivalent spring stiffness of the lower an Therefore, from Table 2, page 5 70, of Reference 8.3.4; the total spring lower and upper tube in series is:
8'I
l I
f lower and upper tubes, individually, (where A, modulus ofelasticity, and tube lengths, respectively) are:
I I
i 1
From the model in Figure 81, the forced tube displacement,ba, due is:
1 I
g Also, flora equation 15.142, page 15 27, of Reference 8.3.5; thc axialload F I
I The calculations from the above equations result in n [
the first suppott plat:. The results are tabulated in Tables 8 3 and 8 8-2
P c'.
S s
Figure 81 Rerolled Tube Model and Emironment 8-3 L
=.
I i
I i
i I
t i
t i
t i
l t
4 f
f 5
I i
i I
r
,d-Figure 8 2 Tube Schematic Series "44" Steam Generators for the Fira Rerolled Joint Location Case i.
s 8-4 i
L o
I L
(
i Figure 8-3 Tube Schematic Series "$1" Steam Generators for the First Rerolled Joint Location Case 85
Table 8-I Axial Member Physical Properties - Westinghouse Series "44" Steam Generators for the First Rerolled Joint Location Case with Tube teck-up MEAN OUTSIDE-INSIDE ~
LENGIH SECTION CORRESFONDING YOUNG'S COEFFICIENT RADIUS RADIUS L
AREA TEMPERATURE MODULUS OF TIIERMAL R.
R4 (in.)
A T.
E EXPANSION 2
(in.)
(in.)
(in )
(*F)
(psix10D a.
(inlin *Fx 109 l
Reference Temperatures:
Primary (Hot) = 609.8 'F Secondary = 521.2 *F Normal Tubes = (2 Ts + T.) / 3 = 580.3 *F 8-6
s a r
^
Table 8-2 Axial Member Physical Properties - Westinghouse Scm-s "$1" Steam Generators for the First Rerolled Joint Location Case with Tube Lock-up i
MEAN OUTSIDE INSIDE -
LENGTH SECTION CORRESPONDING YOUNG'S COEFFICIENT
- RADIUS RADIUS L-AREA TEMPERATURE-MODULUS OFTIIERMAL
-R,^
- R4
_(in.)
A-T.
E-
. EXPANSION
_ T)
(psix 10D -
a.,
-(in.)
(in.)'-
(in.*)
(
(inlin.Tx 101 I
Reference Temperatures-Primary (Hot) = 610.9 7 I
Secondary = 516.8 'F Normal Tubes = (2 Ts + T.) / 3 = 579.5 T l
i i
8-7
i Table 3-3 Axial Loads in Locked Tube - Westinghouse Series "4 r* Stemma Generators i
fcr the First Rerolled Joint Location Case Transicat Tg T.
T.
Lower
. Upper Forced Total Condition
('F)
(*F)
(*F)
Tube Tube Shell Tubesheet Tube Spring Tube 1
I DeSection Deflection Deflection Deflection DeGection Constant Loed
.I L.
4*
Sw L
L ") ~
K P
S
?
(ie.) --
(in.)
(in.)
(in.)
' (in.) -
(bJim.)
Ob.)
l i-
- NOTE: Due to small variation, E and ot., values for normal operation of 100'. power are used.
(1)- L = 6*n + L - L * - 6,*
(2)- K = Total Spring Stiffness for the Tubes (3)- F = K x L 8-8 m
e i
i Table 8-4 l
Axial Loads in Locked Tube - Westinghouse Series "51" Steams Cen._:_.
f for the First Rerolled Joint Location Case l
t I
Transient Tg T
T.
Lower Upper -
Forced
- Total Condition (T) -
-(T)
(T)
Tube Tube Shen Tubesheet
- Tube' Spring Tube Deflection Deflection Denection ocaection Desection constant Lead T6 w bw 6
L L*
K"'
F
[
(ie.)
'(in.)
(in.)
(in.)
- (in.}!
(blim.)
(8b.)
e i
j i
I i
l l
1 4
- NOTE: Due to small variation, E and w values for nonnel operation of 100% power are used.
(I)- L = L + L-Lw-Qw (2)- K. = Total Spring Stiffness for the Tubes i
i (3)- F = K x L t
s 8-9 i
i I
~__ _ _ _. _.. _ _ _. _ _ _ _. _ -. _ _ _.
8.1.2 Axial Loading for the Second Rerolled Joim Location Case ne rerolled tube schematics for both the Westinghouse Series 44 and 51 steam generators are shown in Figures 8 4 and 8 3, respectively, for the second rerolled location case. De rerolled joint is 2 inches from the secondary face of the tubesheet for both series steam generators. De gructural modelis a symem of axial members with properties and boundaries as shown in Tables 8 5 and 8 6 for Series 44 and $1 steam generators, respectively. He material properties (i.e. modulus of elasticity and mean coefficient of thennal expansion) come from Reference 8.3.6. De axial load on the rerolled tube is due only to the thermal expansion between Points A and B.
De calculations use the same equations that are detailed in Section 8.1.1 and result in a l
- 1. He remits are tabulated in Tables 8 7 and 8 8.
J 9
L A
4 8-10
l
- .4 i
1
+
4 3,
4 y*;
i..
e 4
4 i
1 s
4 T
4 i
h a
f i
il N
3 i-J.-
9 I
n v
. t c
1
.I b
t
- Figure 8-4 Tube Schematic - Series "44". Steam Generators for the 4
Second Rerolled Joint Location Case
~ 8-11 h
e-4--m6, v
v<.i-e e
+ -,,
,w
--'erw-u.
w--vei+,y er
++we a
w w-seee-r-
-s
-r erv< wn -e**w,w's w
w
-tv--'
e t'
=
1 4
4 Figure 8-5 Tube Schematic - Series "$1" Steam Generators for the Second Rerolled Joint Locatbr. Case -
i
=
t Table 8-5 Axial Member Physical Properties - Westinghouse Series "44" Steam Generators for the Second Rerolled Joint location Case with Tube Lock-up MEAN OUTSIDE -
. INSIDE
. LENGTH SECTION -
CORRESPONDING YOUNG *S COEFFICIENT RADIUS :
RADIUS.
.L AREA
. TEMPERATURE.
MODULUS"'
OFTHERMAIL
- R. '-
.R;~
(in.)
.A T.
E'
- EXPANSIONi
~
- . (in.).
-(in.):
(in.2)
-(*F)
~ [(psi x 10') ?
rx.,,
- (in. Tad *F x 104
'l Reference Temperatures:
Primary (Hot) = 609.8 *F Secondary = 521.2 *F Normal Tubes = (2 Ts + Tm) / 3 = 580.3 *F 8-13 i
Table 8-6 i
Axial Member Physical Properties - Westinghouse Series "51" Steam Generators for the Second Rerolled Joint Location Case with Tube Lock-up MEAN
'OUTSIDE
'INSIDE LENGTH SECTION
' CORRESPONDING YOUNG'S
' COEFFICIENT U RADIUS RADIUS L
AREA TEMPERARJRE -
- MODULUS OFTHERMAL
~R.-
R4 -
(in.)
~A T.
-El EXPANSION (in.)'
(in.).
"(in.')
(*F) 1(psi x'10') ;
' cr.,,
- (in. fat. *F x 109 l
I Reference Temperatures:
Primary (Hot) = 610.9 'F Secondary = 516.8 *F Normal Tubes = (2 Ts 4 T ) / 3 = 579.5 *F 8-14
.---- A
e.
Table 8-7 Axial ~ e-@ in Locked Tube - Westinghouse Series "44" Steam Generators for the Second l'erolled Joint Location Case
~: Transient:..
Tg.:
T.
c T.
Lower LUpper -
> Forced '.
- Total :
Condition 4(*F)/
'('F)"
(*F))
Tube'
. Tube SheH xTubesheet.
Tube.
. Spring
. Tube:
i; : "
Deflection-
. Deflection Deflection- ' Defiedien DeGection.
Constant Load
- Gg
% w.
Q.
Q m; Km.
F
- (in.)
t(in.)-
(in.):
(in.:"
!(iny (Relin.)'.
- (ib.)
)
1
- NOTE: Due to small variation, E and a,,, values for normal operation of 100% power are used.
i (1) - L = Sui + S,.m - 6% w,, - S.,,,
w.,
(2)- K = Total Spring Stiffness for the Tubes (3)- F = K x Swa 8-15
Table 8-8 Axial Loads in Locked Tube - Westinghouse Series "51" Steam Generators for the Second Rerolled Joint Location Case
- Transient T,,a.
T.
T.
Lower -
Upper Forced Total Condition >
- (T)
(T)
-(T)
Tube Tube Shell.
Tubesheet.-
- Tube Spring
.. Tube DeDection Deflection -
Deflection' Deflection 1 DeGection Constant Losd Ew w.
S.,,,,, w Sun.
6m LJ'Y K*'
W (in.)
(in.)
(in.)1 (iri.)
(in.)-
- (Iblin.).
(Ib.) :
s l
- NOTE: Due to small variation, E and (x,,, values for normal operation of 100% power are used.
(1) - La = 6*n + 6m - 6%w - 6,w (2 - K = Total Spring Stiffness for the Tubes (3)- F = K x ba 8-16 I
e ar
8.1.3. Axial Loading for the First Rerolled Joint Case with Na Tube Lock up The rerolled tube schematics for both the Westinghouse Series 44 and'51 steam generators are shown in Figures 8-2 and 8-3', respectively, for the first location case.
I He rerolled joint is 18.345 inches and 17.375, inches from the secondary face of the j.
- tubesheet for the Series 44 and 51 units, respectively. - ne structural model is a system of axial members with propenies and boundaries as shown in Table 8-9 for Series 44 and 51 steam generators. He material properties (i.e. modulus of-f
- elasticity and mean coefBeient of thermal expansion) come from Reference 8.3.6.
i ne maximum axial load on the rerolled tube is obtained when h is ant locked into the first support plate during the faulted accident condition of Main Steam Line Break.
+
From Figure 81, at Point A, the tube is agt locked in the first tube support above the tubesheet and is therefore, free to move independently of the surrounding secondary shell. ne axial load, F, is the sum of the axial load, F., due to the tube's thermal expansion between poims B and C and the axial load, F, due to the p
pressure differential. De axialload, Fa, is a flinction of the spring constant for the lower tube between points B and C, the location of the rerolled tube joint in the tubesheet, and the forced displacement between the tube and tubesheet arrangement at this location. The thermal growth of the tube and tubesheet is represented by 6, and the spring stiffness of the tube by K.
From equation-15.142, page 15-27, of Reference 8.3.5; the spring stiffness for the tube (where A, Fw, and Lac are the cross sectional areas, modulus of elasticity, and tube length, respectively)is:
I From the modelin Figure 8 1, the forced tube displacement,Ssm.a, between Points B and C due to temperature is:
L I
I Also, from equation 15.142, page 15-27, of Reference 8.3.5; the axial load, Fa, due to thermal expansion is:
1 1
ne axialload, F,, due to pressure differentialis:
1 J-where:
P end P are the Secondary and Primary Pressures, respectively.
2 i
8-17
I R. and N are the outer and inner tube radii, respectively.
Therefore, the total axial load, F, is:
1 I
The calculations from the above equations result in a l
- 1. For the [
] for the Series 44 and 51 steam generators, respectively. He results are tabulated in Table 810.
1 8-18
.t...
- .p.
9 4
Table 8-9 i-Axial Member Physical Properties - Westinghouse Series "44" and "51" Steam Generators i
for i
the First Herolled Joint Location Case without Tube Lock-up j
MEAN OUTSIDE INSIDE.
LENGTII SECTION 1 CORRESPONDING -
YOUNG'S ;
COEFFICIENT OFl RADIUS RADIUS BETWEEN AREA?
TEMPERATURE ?
- MODULUS '
THERMAL
- R._
, Ra PTS. B & C A-.
T..
- Ee.,
2 EXPANSION., '
- (in.)b
' (m.) >
lLedi
--(ia.')
- (T).
J (psi x 10')/
A q (g,);
p: 3
- (in.fm. T x 10 )i 4
Series "44" Steam Generators e +
~
m t4-
~ Series"51" Steam Generators s
t 3
'i i
8-19 t
i
.e...
Table 8-10 Axial Loads in Non-Locked Tube - Westinghouse Series "44" and "51" Steam Generators for the First Rerolled Joint Location Case i
. Tube.
Tube -
Series Tube Tubesheet Forced Spring Load' Primary
. Secondary.
. Load Total '
- Steam T,,5 Deflection DeGection Tube Constant due to Pressure Pressure due to.
' Tube Generator r
-('F) between between DeGection KW' lliermal Pi P2D Fi w e;
' Load :
Pts. B & C Pts. B & C LW
. (Iblin.) L Expansion ~
'.(psi)
. (psi)-
1F/'N 17' :
'k 4w (in.).
'. Fa*
- (b.) -
(ib.)'
(in.) -
~ (in.)
(ib.)
t 1
(1) - Sr,c,4 = Sr.s #,.i - S.6.
i (2)- K = (A x E 6.)/ Lee (3)- F. = K x Swa (4)- Primary and Secondary Pressures at 100% Power (5)- Primary and Secondary Pressures at Main Steam Line Break (6)- F, = P x x x R.'- P x x x R;2 -
2 i
(7)- F = Fa + F, t
i 1
8-20 e
8,1.4 Axial Loading for the Second Rerolled Joint Case with No Tube Lock-up The rerolled tube schematics for both the Westinghouse Series 44 and 51 steam generators are shown in Figures 8-4 and 8-5, respectively, for the second rerolled location case, The rerolled joint is 2 inches from the secondary face of the tubesheet for both series steam generators. The structural model is a system of axial members with properties and boundaries as Aown in Table 8-11 for Series 44 and 51 steam generators. The matetial properties (i.e. modulus of elasticity and mean coefBeient of thermal expansion) come from Reference 8.3.6. He maximum axial load on the rerolled tube is obtained when it is nel locked into the first support plate.
The calculations use the same equations that are detailed in Section 8.1.3 and result in a l
l for the Series 44 and 51 steam generators, respectively, at l
]. For the l' l for the Serier 44 and 51 steam generators, respectively. He results are tabulated la Table 8-12.
8-21
Table 8-11 Axial Member Physical Properties - Westinghouse Series "44" and "51" Steam Generators for-the Second Rerolled Joint location Case without Tube Lock-up MEAN OUTSIDE INSIDE -
LENGTII SECTION CORRESPONDING
. YOUNG'S
" COEFFICIENT OF.-
' RADIUS
. RADIUS BE'IWEEN AREA TEMPERATURE MODULUS ~
THERMAL R.
R4,
FTS. B & C A
T.
. E -:..
EXPANSION "
-(in.)-
1(in.).
Lee' (in.') _
[(*F).
(Mx 10$l'
!w
~(in.)-
(inJs'.?Fx 10')
Series "44" Steam Generators -
q I
l l
4 Series"51" Steam Generators -
l i
I l
.t 8-22 g
Table 8-12 Axial Loads in Non-Locked Tube - Westinghouse Series "44" and "$1" Steam Generators for the Second Rerolled Joint location Case Westinghouse Tube Tube-Series' Tube Tubesheet Forced '-
Spring
_ Load Primary
' Secondary
. Load
. Total '
Steam N-Tg Deflection
- Deflection' Tube - ~ ~
Constant
!dueto Pressure Pressure.
- due to" Tube-
.. Generator
. (*F)
! betwien between Deflection ~
K*
Dermal P".
P Pressurei Load 2
Pts. B,- A C Pts. B & C 6*
(iblin.)l Expansion
- (psi)..
' (psi);.
F,* 2 FM
";. Q
- h
- (in.).
Fa* -
(in.)::
Tiin.) 2
~~
-(Ib.)~
!-(Ib;.)-
l(Ib.)
~
l
( l) - L,4 = E.6,,6,,, - Eos.
(2)- K = (A x E 6.) / Lne (3)- Fa = K x L (4)- Primary and Secondary Pressures at 100% Power (5)- Primary and Secondary Pressures at Msir. Steam Line Break (6)- F, = P x x x R 2-P x x x R;'
2 i
(7)- F = Fa + F, t
8-23
e l
=
1 2
8.1.5 Tubesheet Ligament Stresses la calculating the tubesheet ligament stresses for the Westinghouse Series 44 and 51 steam a
generators; the tubesheet ligament stresses in Reference 8.3.3 for a Series 44 'are used as a basis for determining these stresses acting on the rerolled tube joint. Dese tubesheet ligament stresses are also applicable to the Series 51 steam generators based on the following observations.
- 1. Tubesheet bending stresses are inversely propontional to the thickness squared. -ne-i Series 51 thinner tubeseet increases these stresses by a factor of t
- l..
- 2. He large ligament efficiency of the Series 51 steam generators results in a decrease in stress by a factor of t J.
- 3. He product of the above two factors is unity, so_ the two types of generators are evaluated the same.
Based upon the tubesheet ligament stresses for the desian condition (i.e. tubesheet differential pressure of 1750 psi) in Reference 8.3.3 and the location of the rerolled tube joint from the tubesheet surface (primary or secondary face); the linear interpolation for the maximum tubesheet ligament stress at the re-rolled tubejoint location, Su,
, is:
1 I
ne tubesheet ligament stress results at the design condition for various rerolled locations are tabulated in Table 8-13.
I 1
8.2 Plun and Sleeve Pronram Anplicabihty As previously discussed, ABB/CE has extensive experience in the area of rolling. De mechanical plug rolling program ano the advanced sleeve rolling program both utilize torque levels similar to E
those developed for the tube reroll program. Numerous analyses and test programs have been
_ performed to support the plug and sleeve installation processes. Discussions of these programs can be found in References 4.7 and 4.8 that were mentioned in Reference 8.3.7.
E 8,
o j.
Table 8-13 P
Tubesheet Ligament Stresses for Westinghouse Series "44" and "51" Steam Generators at Design Condition TUBESHEET
- t
. TUBE RE-ROLLED LOCATION L LIGAMENT STRESSES 1 (ksi) :
8 25
e 8.3 Etittttists 8.3.1 Westinghouse Steam Generator Standard Information Package, January 04, 1982 (REF-96-002).
8.3.2 Northern States Power Co. (Richard P. Pear;on) Fax to ABB/CE (Dave Stepnick), dated 9/09/96.
8.3.3
" Primary / Secondary Boundary Components Steady State Stress Evaluation",
prepared by P. Wedler, Westinghouse Electric Corp., April 1965 (REF-96-001).
8.3.4 Mark's " Standard Handbook for Mechanical Engineering", 8th Edition,1979.
8.3.5
" Mechanical Engineering Reference Manual", by Michael R. Lindeberg, P.E.,
9th Edition,1994.
8.3.6 ASME Boiler and Pressure Vessel Code, Section 111 for Nuclear Power Plant Components,1986 edition, no addenda.
8.3.7 ABB/CE Report No. CEN-620-P, Revision 01 P," Series 44 & 51 Design Steam Generator Tube Repair Using a Tube Re Rolling Technique", April 1995.
8.3.8 Westinghouse Report No. WCAP-14225, Revision 1, Table 2-3.
8-26
+
4 9.0 EDDY CURRENT EXAMINATION-9.1 Installation Verification Upon completion of the reroll process, an eddy current techn:que, using a bobbin coil or rotating I
coil probe, is employed 'to verify that the hydraulic expansion, where applicable, and reroll joint have been l -
] in the tube.
9.2 ~
Rotatina Probe Examination Upon completion of the.
- ition, an MRPC probe, or equivalent, is pulled through the rerolled tube to detect tube indications. Since the parent tube, with known ECT indications, has been worked with both a hydraulic expansion and a hard roll, an inspection is necessary to determine if the original indications have changed. The rotating probe resuhs will be compared with previous test results in order to determine whether or not the originalindications have propagated. This test will be used to verify that the F' and EF* criteria of undegraded hard roll tube length above presious indications are met.
9-1
w J
~
10.0 EFFECT OF REROLLING ON OPERATION g
De effect of any tube repair process on the system operation invoh'es flow rate and heat transfer.
' For the case of flow rate, the reroll process will have no detrimental effect. There are no l
restrictions to ' primary coolant flow introduced by this process, with the exception of a tube collapse condition.
3
~
As described in Section 7A, collapse tests were conducted on samples with sludge deposits placed f
in the annulus between the tube and tubesheet. Tube collapse was not seen in any of these samples.
However, a test sample was prepared with (no sludge, but) a full column of water in the annulus between the tube and tubesheet. De water was trapped between the original tube rolled joint and the last terolljoint (located approximately 2 inches from the secondary face of the tubesheet). The sample was placed in an oven for approximately eight hours at 650*F. Tube collapse, in the form of a localized I.D. bulge, was seen at the midpoint between the two rolled joints. Dis is a self relieving condition (as more volume is added to the annulus as the bulge is forming) and the collapse process was stopped before tube I.D. to I.D. contact was made. A 1/2" O.D. go-no-go gage was successfully passed through the bulged area.
His is an extremely conservative case, since it is unlikely that there would be a complete absence of sludge, allowing the annulus to be filled with pure water.
i ne overall resistance to heat transfer between 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 there is no flow rate change with the exception of a tube collapse condition, there is no change in primary side film resistance. Since the rerolling operation takes place in the tubesheet region, there is no effect on heat transfer through the tube wall nor on secondary side film resistance.
In summary, the rerolling operation does not affect the primary system flow rate or the heat transfer capability of the steam generators.
T 4
+
e L
10-1
4 ATTACHMENT 4 Combustion Engineering Affidavit
.a AFFIDAVIT PURSUANT TO 10 CFR 2.790 l, S. E. Ritterbusch, depose and say that I am the Manager, Licensing Projects, of Combustion Engineering, Inc., duly authorized to make this affidavit, and have reviewed or caused to have reviewed the information which is idaantified as proprietary and referenced in the paragraph immediately below I am submitting this affidavit in conjunction with the application of Northern States Power Company, 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:
Report CEN-620-P, Rev. 04-P, " Series 44 & 51 Design Steam Generator Tube Repair Using a Tube Rerolling Technique," September,1997 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.
i 1.
The information sought to be withheld from public disclosure, is owned and has been held in confidence by Combustion Engineering. It consists of l
v _,,
o
' details and supporting test data related to a tube rerolling technique for returning steam generator tubes to service.-
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 customanly 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 confidence. The details of the aforementioned system were provided to the Nuclear Regulatory Commission via letter DP-537 from F. M. Stem 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 ieceived 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 manu'actured and sold by major pressurized water reactor competitors of Combustion Engineering.
b.
Development of this information by Combustion Engineering l
required tens of thousands of dollars and hundreds of 1
I
0 4
3-manhours of effort. A competitor would have to undergo similar expense in generating equivalent information.
c.
In order to acquire such information, a competitor would also require considerable time and inconvenience to develop and validate a similar tube rerolling repair technique.
d.
The information consists of details and supporting test data related to a tube rerolling technique for returning steam generator tubes to service, the application of which provides a competitive economic advantage. The availability of such information to competitors would enable them to modify their product to better compete with Combustion Engineering, take marketing or other actions to improve their product's position or impair the position of Combustion Engineering's product, and avoid developing similar data and analyses in support of their processes, methods or apparatus.
e.
In pricing Combustion Engineering's products and services, significant research, development, engineering, analytical, manufacturing, licensing, quality assurance and other costs 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 puces reflecting signif%tly lower costs.
f.
Use of the information by competitors in the international marketplace would increase their ability to market nuclear steam supply systems by reducing the costs associated with their technology development. In addition, disclosure would have an adverse economic impact on Combustion Engineering's potential for obtaining or maintaining foreign licensees.
1
0
- ?
4..
Further the deponent sayeth not.
I S. E. Ritterbusch, Manager Licensing Projects Sworn to before me -
this 6 day of
.1997 I
G, Not.vy Pub!ic My c mmission expires:
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