ML20128A605

Proposed Tech Specs Requesting Authorization to Use Steam Generator Sleeves for Repair of Defective Steam Generator Tubes

ML20128A605
Person / Time
Site:	Prairie Island
Issue date:	05/17/1985
From:	NORTHERN STATES POWER CO.
To:
Shared Package
ML20128A500	List: ML20128A494 ML20128A524 ML20128A605 ML20128N156 ML20128N197 ML20128N270
References
TAC-57847, TAC-57848, NUDOCS 8505240273
Download: ML20128A605 (400)

Text

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EXHIBIT B

> Prairie Island Nuclear Generating Plant l License Amendment Request Dated May 17, 1985 Proposed Changes to the Technical Specifications Appendix A of Operating Licenses DPR-42 and 60 Exhibit B consists of revised pages of Appendix A Technical Specifications as listed below: ,

E*88 TS.4.12-2 TS.4.12-4 TS.4.12-5 TS.4.12-6 TS.4.12-7 TABLE TS.4.12-1 TS.6.7-2 8505240273 850512 PDR ADOCK 05000282 p PDR d

r Ts.4.12-2 REV l

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2. The first sample of tubes selected for each in-service inspection 'subtequent to the preservice inspection) of each steam-generator shall include:

(a) All tubes that previously had detectable wall-penetrations (>20%) that have not been plugged or sleeve repaired in the affected area.

(b) Tubes in those areas where experience has indicated potential problems.

(c) A tube inspection [ pursuant to Specification 4.12.D.1. (h)]

shall be performed on each selected tube. If any selected tube does not permit the passage of the eddy current probe for a tube inspection, this shall be recorded and an adjacent tube shall be selected and subjected to a tube inspection.

3. The tubes selected as the second and third samples (if required by Table TS.4.12-1) during each inservice inspection may be subjected to a partial tube inspection provided:

(a) The tubes selected for these samples include the tubes from those areas of the tube sheet array where tubes with imperfections were previously found.

(b) The inspections int!ude those portions of the tubes where imperfections were previously found.

~The results of each sample inspection shall be classified into one of_the following three categories:

Category Inspection Results C-1 Less than 5% of the total tubes inspected are degraded tubes and none of the inspected tubes

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are defective.

C-2 One or more tubes, but not more than 1% of the total tubes inspected are defective, or between 5% and 10% of the total tubes inspected are degraded tubes.

C-3 More than 10% of the total tubes inspected are degraded tubes or more than 1% of the inspected tubes are defective.

Note: In all inspections, previously degraded tubes must exhibit significant (>10%) further wall penetrations to be included in the above percentage calculations.

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TS.4.12-4 REV

- D. Acceptance Criteria

1. 'As used in this Specification:

- (a) Imperfection means an exception to the dimensions,

finish or contour of a tube from that required by-

' fabrication drawings or specifications. Eddy-current-testing' indications below 20% of the nominal tube wall thickness, if detectable, may be considered as imperfec-tions.

(b) Degradation means a service-induced cracking, wastage, r

wear or general corrosion occurring on either inside

, or outside of a tube.

'(c) . Degraded Tube means a tube containing imperfections

. >20% of the nominal wall thickness caused by degrada-tion.

_ (d)  % Degradation means the percentage of the tube wall thickness affected or removed by degradation.

(e)- Defect means an. imperfection of such severity that it exceeds the plugging limit. A tube containing a defect.is defective.

(f) Repair Limit means the-imperfection depth at or beyond which the tube shall be removed from service .l by plugging or repaired by sleeving because it may become unserviceable-prior to the1next inspection and is equal to 50% of the nominal tube wall thickness.

If significant general tube thinning occurs,'this criteria will be reduced to 40% wall penetration.

(g) Unserviceable describes the condition of a tube if it leaks or contains a defect large enough to affect its structural integrity in the event of an Operating Basis' Earthquake, a loss-of-coolant accident, or a steam line or feedwater line break.

(h) Tube Inspection means an inspection of the steam y- generator tube from the point of entry (hot leg side) completely around the U-bend to the top support of the cold leg.

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.. l TS.4.12-5 REV

2. The steam generator shall be determined OPERABLE after completing the corresponding actions (plug or repair by I' sleeving, all tubes' exceeding the repair limit and all tubes containing through-wall cracks) required by Table TS.4.12-1.

E. ' Reports

1. Following each in-service inspection of steam generator tubes,;1f there are any tubes requiring plugging or

. sleeving, the number of tubes plugged or sleeved in each steam generator shall be reported to the Commission within

~15 days.

2. The results of steam generator. tube inservice. inspections shall be included with the cummary reports of ASME Code Section XI inspections submitted within 90 days of the C end of each refueling outage. Results of steam generator

' tube inservice inspections not associated with a refueling outage shall be submitted within 90 days of the completion '

of the inspection. These reports shall include: (1) number .

and extent of tubes inspected, (2) location and percent of wall-thickness penetration for each indication of an imperfection, and (3) identification of tubes . plugged.

3. Results of steam generator tube inspections which fall into Category C-3 require notification to the Commission prior to resumption of plant operation,~and reporting as a Reportable Occurrence with prompt notification with written followup. 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.

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~TS.4.12-6 REV BASIS The Surveillance Requirements for inspection of the steam generator tubes ensure that the structural integrity of this portion of the RCS will be maintained. The program for inservice inspection of steam.

generator tubes is based on a modification of Regulatory Guide 1.83, Revision 1. In-service inspection of steem generator tubing is essential in order to maintain surveillance of the conditions of the tubes in the event that there is evidence of mechanical damage or progressive degradation due to design, manufacturing errors, or in-service conditions that lead to corrosion. In-service inspection of steam generator tubing also

.provides a means of characterizing the nature and cause of any tube degradation so that corrective measures can be taken.

The plant is expected to be operated in a manner such that the secondary coolant will be maintained within those parameters found to result in negligible corrosion of the steam generator tubes. If the secondary coolant chemistry is not maintained within these parameters, localized corrosion would most likely result in stress corrosion cracking.

The extent of cracking during plant operation would be limited by the limitation of steam generator leakage between the primary coolant system and the secondary coolant system (primary-to-secondary leakage = 1.0 gpm).

Cracks having a primary-to-secondary leakage less than 1.0 gpm during operationwillhaveanadequatemargino{safetyagainstfailuredueto loads imposed by design basis accidents. Operating plants have demonstrated that prima'ry-to-secondary leakage as low as 0.1 gpm will be detected by radiation monitors of steam generator blowdown. Leakage in-excess of 1.0 gpm will require plant shutdown and an unscheduled eddy current inspection, during which the leaking tubes will be located and plugged or sleeved.

Wastage-type defects are unlikely with proper chemistry treatment of secondary coolant. However, even if this type of defect occurs it will be found during scheduled.in-service steam generator tube inspections. Repair will be required of all tubes with imperfections that could develop defects having

, less than the minimum acceptable wall thickness prior to the next inservice inspection which, by the definition of Specification 4.12.D.1.(f), is 50% of the tube or sleeve nominal wall thickness. Wastage type defects having a wall L thickness greater than 0.025 inches will have adequate margins of safety againstfailurefuetoloadsimposedbynormalplantoperationanddesign basis accidents. Steam generator tube inspections of operating plants have Testimony of J Knight in the Prairie Island Public Hearing on 1/28/75.

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TS.4.12-7 REV BASIS (continued)

-demonstrated'thecapabilitytoreliablydetectwastagetypede{ectsthat have' penetrated 20% of the original 0.050-inch wall _ thickness.

Whenever the results of any steam geners.cor tubing in-service inspection fall into' Category C-3, these results will be promptly reported to the Cosumission prior to resumption of plant operation. Such cases will be considered by the Commission on a case-by-case basis and may result in a requirement for analysis, laboratory examinations, tests, additional' eddy-current inspection, and revision.of the Technical Specifi-cations,'if.necessary.

= Degraded steam generator tubes z.ay be repaired by the installation of sleeves

' which span the section of degraded steam generator tubir.g. _A steam generator tube with a sleeve installed meets the structural requirements of tubes which

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are not degraded.

- The following sleeve designs have been found acceptable by the NRC Staff:

a. Westinghouse Mechanical Sleeves (WCAP-10757)

b. Westinghouse Brazed Sleeves (WCAP-10820)

c. ' Combustion Engineering Leak Tight Sleeves (CEN-294-NP) l Other sleeve designs shall be evaluated in accordance with the requirements of 10 CFR Part 50, Section 50.59. In addition, a copy of the safety evaluation and other relevant descriptive information related to designs other than those described above will be submitted for the information of the NRC Staff at least 30 days prior to use.

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Testimony of L Frank in the Praitla Island Public Hearing on 1/28/75.

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' TABLE TS.4.12-1 '?

STEAMIGENERATOR TUBE INSPECTION <

t

IST SAMPI.E INSPECTION 2ND SAMPLE INSPECTION 3RD SAMPLE INSPECTION q Sample Size Result Action Required Result Action Required Result Action Required A minimum of C-1 None N/A N/A N/A N/A^

S Tubes per S.G. C-2 Plug or sleeve defec- C-1 None N/A N/A

, tive tubes and j inspect additional C-2 Plug or slceve defec- C-1 None

] 2S tubes in this S.G. tive tubes and inspect C-2 Plug or sleeve defec-

, additional 4S tubes tive tubes in this S.G. C-3 Perform action for C-3 result of first sample C-3 Perform action for N/A N/A

! C-3 result of first sample

C-3 Inspect all tubes in All other None N/A N/A this'S.G., plug or S.G.s are sleeve defective C-1 tubes and inspect Some S.G.s Perform action for N/A N/A 2S tubes in each C-2 but no C-2 result of second other S.G. additional sample Prompt notification S.G. are to NRC. C-3

, Additional Inspect all tubes in N/A N/A 2

S.G. is C-3 each S.C. and plug or sleeve defective tubes.

,! Prompt notification to NRC.

d i S=3%; When two steam generators are inspected during that outage. N l S=6%; When one steam generator is-inspected during that outage. g l Y' 1

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TS.6.7-2 REV

2. Occupational Exposure Report. An annual report of

. occupational exposure covering the previous calendar year

-shall be submitted prior to March 1 of each year.

The report should tabulate on an annual basis the number of station, utility.and other personnel (including con- ,

tractors) receiving exposures greater than 100 ares /yr and their associated man-res exposure according to work and job

-functions, e.g., reactor operations and surveillance, inservice inspection, routine maintenance, special maintenance (describe maintenance), vaste processing, and refueling. The dose assignment to various duty functions may be estimates based on pocket dosimeter, TLD, or film badge measurements. -Saall exposures totalling less than 20% of the individual total dose need not be accounted for. In the aggregate, at least 80%

of the total whole body dose received from external sources shall be assigned to specific major work functions.

3. Monthly Operating Report. A monthly report of operating statistics and shutdown experience covering the previous month shall be submitted by the 15th of the following month to the Office of Management and Program Analysis, U.S. Nuclear

. Regulatory Commission, Washington, DC 20555.

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( ) This report supplements the requirements of 10 CFR 20, Section 20.407.

If 10 CFR 20, Section 20.407 is revised to include such information, this Specification is unnecessary.

KAP-10757 SG-85-02-029 NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT LICENSE AMENDMENT REQUEST DATED MAY 17, 1985 EKHIBIT C

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PRAIRIE ISLAND UNITS 1 AND 2 STEAM GENERATOR SLEEVING REPORT ,

(Mechanical Sleeves)

Jcnuary 1985 -

WESTINGHOUSE PROPRIETARY CLASS 3 8

PREPARED FOR NORTHERN STATES POWER COMPANY WESTINGHOUSE ELECTRIC CORPORATION STEAM GENERATOR TECHNOLOGY DIVISION P.O. 80X 855 PITTSBURGH, PA 15230 1751c/0223c/020685:5 1

i PROPRIETARY DFORM& TION NOTICE ,

TRANSMITTED HREWITH ARE PROPRIETARY AND/0R NON-PROPRIETARY YmN OF DOCUENT3 FUMI 5HED TO ME NRC IN CGDIECTION WITH REQUEST 3 POR GBRIC AND/OR PLANT SPECIFIC RBIEW AND APPROFAL.

IN ORDER I.CGIFORM TO 1HE REQUIRDEf!3 'M 10CFR2.790 W THE COBRESSION'S RENILATIONS CONCEMING HE PRDIECTION W PROPRIETART INFORM & TION S0 SUBMITTED .

TO THE NRC, THE INFORM & TION 1RIICH IS PROPRIETARY IN THE PROPRIETART YERSIONS IS CONTAINED WIIMIN BRACKET 3 Alm WHERE THE PROPRIETARY DFORMATION HAS BEEN DELETED IN THE NON-PROPRIETART Ymm ag.T THE BRACKE!3 REMAIN, THE INFORMATION THAT WAS CGITAINED WIIHH THE BnAmm IN THE PROPRIETARY VERSI0llS i HNING BEN DEI.ETED. HE JUSTIFICATION FOR CLAIMING THE DFORMATION 30 DESIGNATED AS PROPRIETARY IS INDICATED IN Bc!H Vmtm3 BY EANS & LNER CASE LIITERS (a) THROUGH (g) CONTAINED WITHIN PARDmH3E3 LOCATED AS A SUPERSCRIPT DREDIATELT FCLLWDC THE BRACKETS BC.3ING EACH ITD( OF INFORMATION BEING IDetTIFIED AS PROPRIETART OR IN THE MHGD OPPOSITE SUQi DIFORMATION. THESE LNH CASE LEITERS REFER TO THE TYPES & INFORMATION WESTINGHOUSE CUSIDMARII.T HG D3 IN CONFIDGCE IDENTIFIED IN SECTIONS (4)(ii)(a) through (4)(11)(g) 0F THE AFFIDAVIT ACCOMPANTDIG WIS TNAN3MITTAL PURSUANT TO 10CFR2.790(b)(1).

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CllRINTT OF F ' : letY:

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.5e' fore an, the undersigned authority, personally appeared Robert A. 'diesemann, who, being by as duly sworn ac:::rting to law, deposes and says that he is authorized to executa this Affidavit on -

behalf of Westinghouse ElecTfc #Corporation (*'destinghause") and that .

the aver.nents of fact, set forth fn this Affidavit are cae and carrect to the best ot his knowledge, fM!srmation, and belief:

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Resort A. Wtesaraann, Manager -

Regu14tary and Lagislative Affairs l ,

Suorn to and subsc:-ibed -

before me this I day of < b[d 980. ,

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- .a .. .- j (1) I. am Managar of Reg Iat:ry and Lagisladve Affairs in ce .'luclea.r.

Tec..nciosy 31 vision of Westngacusa IiectMc Cer,x:rsten, and as sucs, I have teen specimally delegatad ce funcden of. rsy'iewing.

the Mgr-!stary infomaden scustr: c: he wicheid fr:m ';:ublic dis- '

c!csure in c=nnec:teri with nuclear ;cwer plant ifcansing ce rule-making 9. Mags, and as auGrM to apply fer f ts witaholding  ;

on behalf of Ca %estinghause 'al atar Reac ar Civisions.

(Z) f. as making this Afdidavit in c=nfcmance wie i:he pr: visions of -

10CFR 5ecton 2.790 cf es Cennission's regulations and in conjunc-tfon wfe the Westinghouse appTication .ftr witanciding ac==mmanying '-

cis Affidavit. -

(2) I have personar knowledge of the critarta and precadures utilized by Westnghcuse Nuclear Energy systans .in designating information as a trade seerstJ privileled or as cenfidential c=smarcial or ,

financial in.L tton.  :

(4) Pursuant ts the. previsicas of paragrastr (b)(4) of fecdhn 24790 of the Csesrission's regulations, ce fol. lowing is funished for c:n- .

tidtesdon by ca Cenurission in datarsining whetner ce information sought to be withhoid 4cm cualic disclosure should be wicheld.

(,1) The infor.nati.cn scught en be witheid frza ;uulic dis.- -

closure is otsted and has. been he'Id in c=nfidanca by Westinghause. >

t (ii) The faa. don is of a type cust:maMiy held in c=nfi-danca by Westinghouse and not cust=marily disclosed ts tha pubite. Westnghouse has a radonal basis for datamining es y/ pas of informaden cust:maH1y' held in c:n'idenca by it and, in eat c=nnectien, utflt:ss a systam :s deramine wnen and wherner :s ncid car ain :ypes of infor :a:icn in i

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c=nfidenca. The aanticaden of cat systan and de sum.

sunca of t: tat systan.c=nsttutas Wesdngncusa";o1fcy anc .:r:vides de esdenal basis required. .

Unser 'dai systam,. fufw. s:ca is held. in c=nfidenca ff

it faits in one or acre of seversi types, ce rsleasa of eictr might resuit, in es Toss of' an exiseng or gr w a1 c=mmetteve advanugia,. as follows

! . (a) The infonation reves.ls the disengnisMng aspec-s of a pncass (or c=mponent, st: acture, t=oi, secod, -

, etc.) ears prevention of its use by any of Westingneuse's c=mpetitan wiecut licanse frem Wesdnghouse c=nst-tutes a w.s;tive,econcaic advanage over other c=maanies. ' -

m (h) I,t consists of suaporting data.,. including tast dau,.

reTative ts a prucass '(or causenent, st:accre, toot, anced, etc.), es application of dich data ' secures y 4. c=mpetitive eennemie advanuge, e.g., by opdmi=adon or improved. arketaM11ty. '

Its use by a. c=mmeritar would reduca Ms expenditure l (c) ,

of resources or isonve Ms c=msetttve ;:esiden in' de design, anufas.are, stripment, insuilation, assur '

anca of quality, or Ticansing a sinfTar pncuct. ,

(d) It reveals cast or prica in.N._ tics,, pnductica casac-ittes, budget levels, or < !al straugies of Wesdnghouse, its cust=mers or sucoliers.

1 i (e) It reveals aspects of past, present, er future Wesdngneuse er cust::=ur ^;nced develecmenc :: Tans anc :ragm :f i

ocancial c

a:=artial valus *.: ',lastingncusa.

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, (f) It c:ntains patanuale' ideas, for wafe.i ;atant pr.-

W.cn my ha desiracle. .

(g) It it not ce pnper y of Wesdngneuse, but ast he trea. tad as p.wristary by Wesdnghouse ac=:rting to agreements with the owner.-

Thors are. sound ;olicy reesans behind ce Wesdngneuse systan wMch include the following:

(a) The use of s'uch infor. nation by Wesdaghouse gives Westingneuse a c=mpetitive advantage over its campatitors.

It is, therefore, withheld from disclosure to protect the Wesdn@~ga c=mpetitive positica. ,

i (p) It is informatiert wMch is markeuhle in many ways.

The extant to which such 1..L. tion it a'vailable. to c=mpetttars dinrinishes ce Westingneuse abfif ty ts

. .- sail products and services invalving the use of ene information.

(c) lise by our c=mpetitor would ;ut Wesdaglicuse at a c=mpetitive disadvantage by . :. ucing his ex enditure

'Of resources at. Our sapense. '

(d) Each c=mmunent of pnprietary infomaliian perdnent ta a'perdcular c=mseritNe advantage is potantially as valuable as ce tatal c=mmatitive advantaga. If c=mmedtars ac:;uire c=mmenents of pneristary infoma-tien, any one c=mcenent may be ene key is ce andre pu==le, theracy decriving Wesdngncuse of a c::mcetitive advantage.

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(e) U.i. -ictad disclosure would joccardza. ce position of pruninancs of Westnghcusa in de Arld arket, and theracy give a market advanuge to the 9

mmedtion in cosa c=untMes ,.,

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(f) The Westinghouse capacity ta invest enrporata assatz.

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. in research and development decends usen ce sue = ass .

, in obtaining and afnn'tning a cmapetitive advanage.

(iii)

The inforation is being transmitted ts the Ccanission in .

confidenca and, under es provisions of 10CFR 5ecton 2.790, it is to be received in confidenca by' ce Cannission.

(iv) The information sought to be protec.ad is not available in ,

puhtic sourcas ta ce best of our knowledge and beltef.

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s-(v) The rwrieury 1.ir-tfon soughs ta he wich' eld in cts  ;

sutettut is est difcir is as,,,wriataly aerkad SI-5p4(80) i

' 5outhern Califamia Edison Recair. Recort" (PropMeury).

_ This report hs.s beerr prepared for aqd is being suhrit.ed ts tha Staff at ca request of Southern California Edison. l The Mrs details the design of ce sleeves cat are ts be .

insulled in ce San Onofre Unit I staam geners:srs. The i report. also includes ce design analysis, ca ast veHfica,-

tien program and descMptions of the expanded mec::anical plug, the rolled plug and ce channel head dec=numinaden

! prCCass.

This i..." . . don is part of cat which will' enable Wesdngneuse ts

i (a) Acoly for parant protaction.

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Optimi:a staam genert :r recair tachnicues. = ax:and (b) es sortica Iffe of s aam generatars. ' ,-

(c.) Assist itr.cust:mers ti comin NRC approval.

(d) As.fi es design bas'ir for de staam generat:r

repairr and insu11ation macods. -

Fm.w. tMs infomadon has suasuntial c=nnardal tatue

. as follows: -

(4)  %;.dghouse plans ts sell the recair techniques and,

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equipment descMhed. in part by ce infer =adon.

(b) Westnghouse ca,n, sail repair sorticas based upon taa ,

@r enca gained and. the insu11ation equipment '

and anthods developed. .

Public disciosure of this infomation is likely to cause sUhstantiaT ham to ce c:mpetitive position of Westinghouse becausa (T) it would result in me loss of valuable patant  :

Mghtr, and (2) it would enhanca de ability of c=moedt:rs to design, annufacture, veHff and sell suas generatar repair tachniques for c:enardal power reac=rs wicout <

c=mmensurata expenses.

The development of es secods and eouipment descMbed in -

part by the information is de result of acolying tne results of many years of expeManca in an intansive Westinghouse ef'er and tne ex=enditure of .a c:nsicarable sum cf =eney.

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. for staan generatar repair tac.niques.

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WESTINGHOUSE PROPRIETARY CLASS 3 I

TABLE OF CONTENTS

.~

Section Title P3 ,

1.0 INTRODUCTION

, 1-1 2.0 SLEEV!NG OBJECTIVES AND BOUNDARIES 2-1 9

2.1 Objectives 2-1 2.2 Sleeving Boundary 2-1 3.0 DESIGN 3-1 3.1 Sleeve Design Documentation 3-1 -

3.2 SleeveDesignDescription

• 3-1

~

3.3 Design Verification: Test Programs 3-6 3.3.1 ' Design Verification Test Prograe Sumary e3-6 3.3.2 Corrosion and Metallurgical Evaluation 3-7 3.3.3 Upper and Lower Joints 3-17 3.3.4 Test Program for the Lower Joint 3-18 3.3.4.1 Description of Lower Joint Test Specimens 3-18 3.3.4.2 Description of Verification Tests for 3-22 the Lower Joint 3.3.4.3 Leak Test Acceptance Criteria 3-23 3.3.4.4 Results of Verification Tests for Lower Joint 3-23

. I 1751cIO223c/020185:5 2 l  !

WESTINGHOUSE PROPRIETARY Ct.A55 3 TA88.E OF CONTENTS (Continued) .,

Section Title P3 -

3.3.5 Test Program for the Upper Hybrid Expansion '

Joint (HEJ) , 3-25 -

3.3.5.1 Description of the Upper HEJ Test Specimens 3-25 3.3.5.2 Description of Verification Tests for the Upper HEJ 3-29 3.3.5.3 Results of Verification Tests for the Upper HEJ 3-29 3.3.6 Test Program for the Fixed-Fixed Mockup 3-34 3.3.6.1 Description of the Fixed-Fixed Mockup 3-34 3.3.6.2 Description of Verification Tests for 3-43 the Fixed-Fixed Mockup 3.3.6.3 Results of Verification Tests for the 3-43 Fixed-Fixed Mockup 3.3.7 Effects of Sleeving on Tube-to-Tubesheet Weld 3-45 3.4 Analytical Vertf tcation 3-47 3.4.1 Introduction 3-47 3.4.2 Component Description ' 3-47 3.4.3 Material Properties 3-49 3.4.4 Code Criteria 3-49 3.4.5 Loading Conditions Evaluated 3-49 3.4.6 Methods of Analysis 3-52 3.4.6.1 Model Development 3-52 3.4.6.2 Themal Analysis 3-54 3.4.6.3 Stress Analysis 3-56 3.4.7 Results of Analyses 3-58 3.4.7.1 Primary (Pressure) Stress 3-58 3.4.7.2 Range of Primary and Secondary Stress Intensities 3-53 3.4.7.3 Range of Total Stress Intensities 3-65 1751c/0223c/020185:5 3

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. 1 i

, , WESTINGHOUSE PROPRIETARY CLASS 3 TA8LE OF CONTENTS (Continued) ,

Section Title P3 3.4.8 References 3-67 3.5 Special Considerations 3-69 3.5.1 Flow Slot Hourglassing 3-69 3.5.1.1 Effects on Burst Strength 3-69 3.5.1.2 Effects on Stress Corrosion Cracking Margin 3-69

, 3.5.1.3 Effect on Fatigue Usage 3-69 e -

3.5.2 Tube Vibration Analysis 3-70 3.5.3 Sludge Height Thermal Effects 3-70 3.5.4 Allowable Sleeve Degradation 3-70 -

3.5.5 Effect of Tubesheet/ Support Plate Interaction 3-73

~

3.5.6 Comprehensive Cyclic Testing 3-73 3.5.7 Evaluation of Operation with Flow Effects Due to Sleeving 3-74 3.5.8 Alternate Sleeve Materials 3-77 1751c/0223c/020185:5 4

e WESTINGHOUSE PROPRIETARY CLASS 3 TA8LE OF CONTENTS (Continued) -

Section Title P3 4.0 PROCESS DESCRIPTION 4-1 4.1 Tube Preparation

4-1 a 4.1.1 TubeEndRolling(Contingency) 4-1 4.1.2 Tube Honing 4-3

. 4.1.2.1 C 'Ja.c.e g,,,,, 4,3 411.2.2 Ory Honing 4-4 ,

4.1.3 FiberopticInspection(Contingency) 4-4 4.2 Sleeve Insertion and Expansion 4-4 4.3 Lower Joint Seal -

4-6 4.4 Upper Hybrid Espansion Joint (HEJ) 4-7 4.5 Process inspection Sampling Plan 4-7 4.6 Establishment of Sleeve Joint Main Fabrica- 4-9 tion Parameters 4'.6.1 Lower Joint 4-9 4.6.2 Upper HEJ 4-9 i

l 1751c/0223c/020685:5 5 i IV e 8 0

, WESTINGHOUSE PROPRIETARY CLASS 3 5.0 SLEEVE / TOOLING POSITIONING TECHNIQUE ., 5-l*

5.1 Remotely Operated Service Arm (ROSA) 5-1 5.2 Alternate Positioning Techniques 5-3 6.0 NDE INSPECTA81LITY 6-1 6.1 Eddy Current inspections 6-1 6.2 Suspary 6-16 7.0 ALARA CONSIDERATIONS FOR SLEEVING OPERATIONS 7-1 7.1 ROSA Sleeving Operations 7-2 7.2 Nanipulator End Effectors 7-2 7.2.1 Sleeye/ Tooling End Effectors 7-2 7.2.2 In-Process Operations 7-3 7.3 Control Station in Containment a7-3 7.4 Potentials for Worker Exposure 7-3 7.4.1 Nozzle Cover and Camera Installation / Removal 7-4 7.4.2 Platform Setup / Supervision 7-4 7.5 Radweste Generation 7-5 7.6 Airborne Releases 7-7 7.7 Personnel Exposure Estimate 7-7 .

8.0 INSERVICE INSPECTION PLAN FOR SLEEVED TUSES 8-1 t

1751c/0223c/020185:5 6 V

a

, WESTINGHOUSE PROPRIETARY CLASS 3 LIST OF TABLES .,

Table Title P,ajjr a.

3.1-1 ASME Code and Regulatory Requirements 3-2 3.3.2-1 Summary of Corrosion Compar.ison Data for 3-11 Thema11y Treated Inconel Alloys 600 and 690 .

3.3.2-2 Effect of 0xidizing Species on the SCC Suscepti- 3-12 bility of Thermally Treated I-600 and I-690 C-rings

,in Demerated Caustic.

3.3.3-1 Design Verification Test Program - Corrosion 3-19 3.3.4.3-1 Allowable Leak Rates For Model 51 Steam Generators 3-24 3.3.4.4-1 Test Results for the Model 44 As-rolled Lower 3-26 Joints -

3.3.5.3-1 Test Results for Model 44 HEJ's Formed Out 3-35 of Studge 3.3.5.3-2 Test Results for Model 44 HEJ's Formed Out of 3-37 Sludge (State Axial Load Leak Test, SLB and ReversePressureTest) 3.3.5.3-3 Test Results for Model 44 ItEJ's Formed in 3-39 Sludge (Fatigue and Reverse Pressure Tests) 3.3.5.3-4 Test Results for Model 44 HEJ's Formed in 3-41 Studge(AxialLoadLeakTestandPost-SLBTest).

3.3.5.3-5 I-690 Limited Scope Test Results 3-42 3.3.6.3 1 Test Results for Model 44 Full Length Sleeves 3-46 l

l 1751c/0223c/020185:5 1 l VI

r WESTINGHOUSE PROPRIETARY CLASS 3 LISTOFTA8LES(Continued) -

Table Title P3 ,

3.4.4-1 Criteria for Primary Stress Intensity Evaluation 3-50 ,

($leeve) 3.4.4-2 Criteria for Prienry Stress Intensity Evaluation 3-51 (Tube) 3.4.5-1 Operating Conditions 3-53 3.4.7.1-1 Dere11a Pressure Loads for Design, Upset, Faulted, and Test Conditions 3-59 3.4.7.1-2 Results of Primary Stress Intensity Evaluations 3-60 Primary Mee rane Stress Intensity 3.4.7.1-3 Results of Primary Stress Intensity Evaluations 3-61 ,

Primary Meerane Plus Bending Stress Intensity, P, + Pb ' -

3.4.7.2 1 Pressure and Temperature Loadings for Maximum 3-62 Range of Stress Intensity and Fatigue Evaluations 3.4.7 P-2 Results of Mexiase Range of Stress Intensity 3-64 Evaluation 3.4.7.3-1 Results of Fatigue Evaluation 3-66 3.5.4-1 Regulatory Guide 1.121 Criteria 3-71 4.0-1 Sleeve Process Sequence Sumnery 4-2 7.5-1 Estimate of Radioactive concentration in 7-6 Water per Tube Honed (Typical) 1751c/0223c/020685:5 8 VII 4 .

f

. WESTINGHOUSE PROPRIETARY CLASS 3 LIST OF FIGURES

- Figure Title ,P,aage 2.2-1 SleevingSoundary[ ]"'C Sleeves 2-3 I .

3.2-1 Installed Sleeve with Hybrid Expansion 3-4 Upper Joint Configuration ,

3.2-2 Sleeve Lower Joint Configuration 3-5 3.3.2-1 SCC Growth Rate for C-rings (150 percent YS and 3-13

~

TLT)in10percentNa0H 3.3.2-2 Light Photo micrographs illustrating IGA 3-14 3.3.2-3 SCC Depth, for C-Rings (150 percent YS) in 3-15 8 percent Na2 50 4 3.3.2-4 i . Reverse U-bend Tests at 360*C (680*F) 3-16 3.3.3 1 Location and Relative Magnitude of Residual 3-20 Stresses Induced by Expansion 3.344.1-1 Lower Joint As-rolled Test Specimen 3-21 l

3.3.5.1-1 Hybrid Expansion Joint (HEJ) Test Specimen 3-30 3.3.5.1-2 HEJ Spe:imens for the Reverse Pressure Tests 3-31 3.3.6.1-1 Fixed-Flued Mockup - HEJ 3-44

. 3.4.2-1 Installed Sleeve with Upper Hybrid Expansion 3-48 Joint Configuration Main Finite Element Model Dimensions 1751c/0223c/020185:5 9 VI!!

L e

. WESTINGHOUSE PROPRIETAAY CLASS 3

~

LIST OF FIGURES .

Figure Title P3 .

6.1-1 Eddy Current Sip als from the ASTM 6-5 Standard, Machined on the Tube 0.0. of '

the Sleeve / Tube Assembly Without -

, 6.1-2 Eddy Current Sipals from the 6-6 Expansion Transition Region of the

• Sleeve / Tube Assembly ( Conventional DifferentialCoilProbe) 6.1-3 Eddy Current Calibration Curve for ASE 6-7 Sleeve Standard at [ ]

with the Conventional Differential Coil Probe 6.1-4 Eddy Current Sipals from the ASTM 6-8 Standard, Machined on the Sleeve 0.0. . .'

of the Steeve / Tube Asseebly Without

~

Expansion (CrossWoundCoilProbe) 8 6.1-5 Eddy Current $1 pals from the ASTM 6-9 Standard, Machined on the Tube 0.0.

• of the Sleeve / Tube Assembly Without Expansion (CrossWoundCoilProbe) 6.1-6 Eddy Current Signals from the Expansion 6-10 Transition Region of the Sleeve / Tube Assembly (CrossWoundCoilProbe) 6.1-1 Eddy Current Calibration Curve for ASME 6-11 TubeStandardat( Ja.c.e and a Mix Using the Cross Wound Coll Probe -

1751c/0223c/020185:5 10 lx 9

Dw e

, WESTINGHOUSE PROPRIETARY CLASS 3 6.1-8 Eddy Current Signal from a 20 Percent Deep 6-12 Hole, Half the Volume of ASTM Standard, Machined on the $leeve 0.0. in the Expansion Transition Region of the Sleeve / Tube Assembly (Cross Wound Coll Probe) 6.1-9 Eddy Current Signal from a 40 Percent ASTM 6-13 Standard, Machined on the Tube 0.0. in

, Espansion Transition Region of the Sleeve / Tube Assembly (Cross Wound Coil

• Probe) 6.1-10 Eddy Current Response of Square and 6-14 Tapered Sleeve Ends Compared to the Expansion, Transitions for the Conventional Bobbin Coil Probe

~

6.1-11 Eddy Current Response of the ASTM Tube 6-15 Standard at the End of the Sleeve Using ,

the Cross Wound Coil Probe and Multifrequency Combination 1751c/0223cl020185:5 11 X

P

.m._ ._ -

s y .

' WESTINGHOUSE PROPRIETARY Ct. ASS 3

1.0 INTRODUCTION

l As part of its ongaing steam generator repair develo' mentp programs, l Westinghouse.has developed the capability to restore degraded steen generator ,

tubes by ess of a sleeve. This technology may be applied to the steam generatcri of Fratrie Island Units 1 and 2 with the objective of restoring the pressure boundary of such tubes and prolon9 i ng the availability of the steam generator heat exchange system.

t To date, nearly 15,000 steam generator tubes at six operating nuclear power plants world-wide have been successfully sleeved, tested, and returned to

• service by Westinghouse. Both mechanical-joint and brazed-joint sleeves of Inconel 600, Inconel 690, and bimetallic Inconel 625/Inconel 690 have been installed by a variety of techniques - Coordinate Transport (CT) system installation, hands-on (manual) installation, and Remotely Operated Service

, Arm (R0SA) robotic installation. Westinghouse sleeving programs have been successfully implemented after approval by licensing authorities in the U.S.

(NRC - Nuclear Regulatory Comdssion), Sweden (SE! - Swedish Nuclear Inspectorate),andJapan(MITI-JapaneseMinistryofInternationalTradeand Industry). .

The sleeving technology was originally developed to sleeve 6,929 degraded tubes (including lenkers) in a plant with Westinghouse Model 27 series steam generators. Process improvements and a remote sleeving system were I

subsequently developed and adapted to a Westinghouse Model 44 series steam generator with ut1112ation in full scale sleeving operations at two operating plants (2,971 and 3,000 sleeves). This technology has also been modified to facilitate insta11ation of 2036 sleeves in a non-Westinghouse steam generator. Most recently, the latest Westinghouse sleeving technology was successfully applied during a demonstration at a European site in a model 51 steen generator.

1751c/0223c/020185:5 12 P

1-1 I

\

WESTINGHOUSE PROPRIETARY CLASS 3 2.0 SLEEVING0'BJECTIVES AND SLEEVING BOUNDARIES 2.1 OBJECTIVES Both Prairie Island Units are Westinghouse-designed 2 loop c-acturized water reactors rated at 1650 MWt each. The tiwo units utilize a total of u

• vertical U-tube steam generators. The steam generators are Westinghouse ho e 51 Series containing heat transfer tubes with dimensions of 0.875 inch nominal 00 by 0.050 inch nominal wall thickness.

9 The sleevin,g concept and design are based on observations to date that the

, tube degradation due to environmental attack has occurred near the tubesheet -

areas of the tube bundle. The sleeve has been designed to span the degraded region in order to maintain these tubes in service.

The sleeving program has two primary objectives: l

1. To sleeve tubes in the region of known or potential tube degradation.

2. To minimize the radiation exposure to alt working perso3nel (ALARA) 2.2 SLEEVING BOUNDARIES Tubes to be sleeved will be selected by radial location, tooling access (due l to channel head geometric constraints), and eddy current indication elevations '

and size. An axial elevation tolerance of one inch will be employed to allow for any potential eddy current testing position indication inaccuracies and degradation growth. Tube location on the tubesheet face, tooling dimensions, L and tooling access permitted by channelhead bowl geometry define the sleeving  ;

boundaries. Figure 2.2-1 shows an estimated radial sleeving boundary for a +

[ la,c.e sleeve as determined by a geometric radius computed froni the channelhead surface-to-tubesheet primary face clearance distance minus the tooling clearance distance. (The actual "as is" bowl geometry will be slightly different in certain areas.) This is the sleeving boundary for a generic Westinghouse series 51 steam generator and represents the maximum sleeving potential with a [ ]a,c.e sleeve. This information along 1751c/0223c/020185:5 13 2-1 l'

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WESTINGHOUSE PROPRIETARY CLASS 3 3.0 DESIGN ,

3.1 SLEEVE DESIGN DOCUMENTATION The Prairie Island steam generators were built to the 1965 edition of Section

!!I of the ASME Boiler and Pressure Vessel Code, however, the sleeves have been designed and analyzed to the 1983 edition of Section III of the Code through the winter 1983 addenda as well as applicable Regulatory Guides. The associated materials and processes also meet the requirements of the Code.

The specific documentation applicable to this program are listed in Table 3.1-1.

3.2 SLEEVE DESIGN DESCRIPTION The reference design of the sleeve, as installed, is illustrated in Figure 3.2-1. [

3ac.e ,

At the upper end, the sleeve configuration (see Figure 3.2-1) consists of a e'

sectionwhichis[

]a,c.e This joint configuration is known as a hybrid expansion joint (HEJ). [

3a,c.e 1751c/0223c/020185:5 15 3-1

WESTINGHOUSE PROPRIETARY Cl. ASS.3 TA8LE 3.1-1 ,,

ASE CODE AND REGULATORY REQUIREMENTS Ites Applicable Criteria Requirement

• Sleeve Design Section !!! E 3200 Analysis 5 3300, Wall Thick- ,

ness O

Operating Requirements Analysis Conditions Reg. Guide 1.8S S/G Tubing Inspec-tibility Reg., Guide 1.121 Plugging Margin Sleeve Material Section II Material Composition -

Section III NS-2000,Identifica-tion, Tests and Examinations i

Code Case M-20 Mechanical Proper-ties Sleeve Joint 10CFR100 Plant Total Primary-Secondary Leak Rate Technical Specifications Plant '..cak Rate l 1751c/0223c/020185:5 16 l

l 3-2

WESTINGHOUSE PROPRIETARY CLASS 3 At the lower end, the sleeve configuration (Figure 3.2-2),,consis'ts of'a section which is [ '

4

]C Tha lower end of the sleeve has a prefomed section to facilitate the seal formation and to reduce residual stresses in the sleeve. ~ '

The sleeve, after' installation, extends above the top 'of the tubesheet and

• spans the degraded region of the original tube. Its length is controlled by the insertion clearance between the channel head inside surface and the primary side of the tubesheet, and the tube degradation location above the tubesheet. - The remaining design parameters such as wall thickness and material are selected to enhance design margins and corrosion resistance-

~

and/or to meet ASME Boiler and Pressure Vessel Code requirements. The upper joint is located to provide a length of. free sleeve above it. This length is added so that if the existing tube were to become severed just above the upper edge of the mechanical joint, the tube would be restrained by the sleeve and therefore axial motion, and subsequent leakage, vould be limited. Lateral ,

motion would also be restricted, protecting adjacent tubes froa impact by the severed tube.

To minimize stress concentrations and enhance inspectability in the area of theupperexpandedregion,[

]a,c.e,f The sleeve material, themally treated Inconel 690 or 600, is selected to provide additional resistance to stress corrosion cracking. (See Section 3.3.2 for further details on the selection of thermally treated Inconel 600 and 690).

1751cIO223cl020185:5 17 3-3

-. ,, . - . _ , . - . . . . . - , _ . . . _ _ . . . - .-.-r. _. , , _ . . . _ , _ _ . _ _ _ - . _ - , . _ _

WESTINGHOUSE PROPRIETARY CLASS 3 Figure 3.2-1 Installed Sleeve with Hybrid Expansi5n Upper Joint Configuration -

1751c/0223c/020185:5 18 3-4 t

m.

T'

, WESTINGHOUSE PROPRIETARY CLASS 3

- l s .

d Figure 3.2-2

~

Sleeve Lower Joint Configuration 1751c/0223c/020185:5 19 3-5

, WESTINGHOUSE PROPRIETARY Ct. ASS 3

~

3.3 DESIGN VERIFICATION: TEST PROGRAMS .,

3.3.1 DESIGN VERIFICATION TEST PROGRAM SUMARY The following sections describe the material and design verification test progrees. The purpose of these programs is to verify the ability of the sleeve concept to produce a sleeve capable of spanning a degraded region in a

- steam generator tube and maintain the steam generator tubing primary-to-secondary pressure boundary under normal and accident conditions. This program -includes assessment of the structural integrity and corrosion resistance of slegved tubes.

i

A substantial data base exists from previous test programs which verify the sleeve design and process adequacy. Much of this testing is applicable to this sleeving program. The sleeve materials to be used, thermally treated nickel chromitse iron alloy (Inconel 600 or 690), are identical to those used in prior sleeving programs. , The standardized mechanical sleeve design is the same as that used in prior sleeving programs. The fabrication of sleeve / tube joints by the combination of [ ]ac.e at both ends of the sleeve was verified and applied'on all programs. Rigorous

~

mechanical testing programs were conducted to verify the sleeve design for various steam generator models, including the Model 44, which has the same tube dimensions as the Model 51. In addition to being dimensionally similar, analysis has demonstrated that the operating conditions of a Model 44 steam generator envelope those of a Model 51. Therefore, much of the Model 44 testing -is directly applicable to the Model 51 steam generators.

The objectives of the mechanical testing programs included:

• 'erify that the leak resistance of the upper and lower sleeve to tube joints meets the leak' rate acceptance criteria.

Verify the structural strength of the sleeved tube under normal and accident conditions.

1 1751c/0223c/020185:5 20 3-6 9

-+ ---n-- -

9-w- ~ -v---*"

, WESTINGHOUSE PROPRIETARY CLASS 3 Verify the fatigue strength of the sleeved tube under,transie'nt loads representing the remaining life of the reactor plant.

Confirm capability for performance of tubes sleeved under conditions such as deep secondary side hard sludge and tube support plate denting

. ' Establish the process parameters required to achieve satisfactory installation and performance. These parameters are discussed in Section 4.6.

The acceptance criteria used to evaluate the sleeve performance are leak rates based on the plant technical specifications. Over 100 test specimens were ~

used in the various test programs to verify the design and to establish process par meters. Testing encompassed static and cyclic pressures, temperatures, and loads.- The testing also included evaluation of joints fabricated using Inconel 600 sleeves as well as Inconel 690 sleeves in Inconel 600 tubes. While the bulk of the original qualification data is centered on Inconel 600 sleeves, a series of limited scope verification tests were run using Inconel 690 sleeves to demonstrate the effectiveness of the joint formation process and design with either material. ~

^

The sections that follow describe those portions of the corrosion (sections 3.3.2-3.3.3) and mechanical (sections 3.3.4-3.3.6) verification programs that '

, are relevant to this sleeving program.

3.3.2 CORROSION AND METALLURGICAL EVALUATION The basic objective of the corrosion and metallurgical evaluation programs conducted was to verify that the sleeving concepts and procedures employed did not introduce any new mechanism that could result in premature tube or sleeve degradation.

Inconel Alloy 600 and Inconel Alloy 690 (I-600 and I-690) cre austentic nickel-base alloys. I-600 has been extensively used, originally in the mill i

annealed' condition, as steam generator tubing in pressurized water reactors.

t 1751c/0223c/020185:5 21 i

3-7

--, -- e---e ,-,,---,-,,,-,.-,-,e- --. - , , . --w-e,

l-WESTINGHOUSE PROPRIETARY Ct. ASS 3

'In recent years, attempts to enhance the IGA-SCC (Intergranular A,ttack-Stress Corrosion Cracking) resistance of I-600 have focused on the application of a themal treatment in the carbide precipitation touperature range (593* to -

760*C). Microstructural modifications have concentrated on the grain boundary region since the SCC morphology in I-600 is predominantly intergranular. The *

.maxiaum enhancement in caustic and primary water SCC performance was correlated with the presence of a semicontinuous grain-boundary carbide l precipitate.  !

I Inconel Alloy 690, which contains a higher chromium content (30 percent) than Inconel Alloy 600 ,has also indicated the ability to exhibit improved ISSCC resistance when thermally treated in the carbide precipitation region. -

The stress corrosion cracking performance of themally treated Inconel Alloys 600 and 690 in both off-chemistry secondary side and primary side envirorsnents ,

has been extensively investigated. Results have continually demonstrated the additional stress corrosion cracking resistance of thermally-treated Inconel '

Alloys 600 and 690 compared to mill annealed Inconal Alloy 600 material.

Direct comparison of thermally treated Inconel Alloys 600 and 690 has further

• indicated an increased margin of SCC resistance for themally treated Inconel Alloy 690. (Table 3.3.2-1). .

The caustic SCC perfomance of util annealed and thermally treated Inconel .,

Alloys 600 and 690 were evaluated in a 10 percent NaOH solution as a function of temperature from 288'C to 343*C. Since the test data were obtaired over variot.s exposure intervals ranging from 2000 to 8000 hours0.0926 days <br />2.222 hours <br />0.0132 weeks <br />0.00304 months <br />, the test data were normalized in terms of average crack growth rate determined from destructive '

exsaination of the C-ring test specimens. No attempt was made to distinguish between initiation and propagation rates.

The crack growth rates presented in Figure 3.3.2-1 indicata that thermally treated I-600 and I-690 have enhanced caustic SCC resistance compared to that of I-600 in the mill annealed condition. The perfomance of thermally treated I-600 and I-690 are approximately equal at temperatures of 316*C and below.

At 332*C and 343*C, the additional SCC resistance of thermally treated Inconel Alloy 690 is observed. In all instances the SCC morphology was intergranular 1751c/0223c/020185:5 22 3-8 -

, WESTIN3 HOUSE PROPRIETARY CLASS 3 in nature. The superior performance of thermally treated.J-690 at higher temperatures is a result of a lesser temperature dependendy.

t.

• Testing in 10 percent Na0H solution at 332*C was performed to index the relative intergranular attack (IGA) resistance of I-600 and I-690. Comparison of the IGA morphology for I-600 and I-690 rings stressed to 150 precent of the 0.2 percent yield strength is presented in Figure 3.3.2-2. Mill annealed

I-600 is characterized by branching intergraaular SCC extending from a 200u front of uniform IGA. Themally treated I-600 exhibited less SCC and an IGA front limited to less than a few grains deep. Thermally treated I-690 exhibited 9 SCC and only occasional areas of intergranular oxide

. penetrations, limited to less than a grain deep. ~

l The enhancement in IGA resistance can be attributed to two factors; heat treatment and alloy composition. A characteristic of mill annealed I-600 C-rings exposed to deaerated sodium hydroxide environment is the presence of

{

intergranular SCC along with uniform grain boundary corrosien referred to as l intergranular attack (IGA). The relationship between SCC and IGA is not well established but it does appear that IGA occurs at low or intermediate stress levels and at altetrochemical potentials where the general corrosion

)

resistance of the grain boundary area is a controlling factor. Thermal i treatment of I-600 provides additional grain boundary corrosion resistance  !

, . along with additional SCC resistance. In the case of I-690, the composition  ;

provides an additional margin of resistance to IGA and the thermal treatment enhances the SCC resistance.

c ,

r The addition of oxidizing species to deaerated sodium hydroxide environments results in either a deleterious effect or no effect on the SCC resistance of thermally treated I-600 and I-690 depending on the specific oxidizing specie and concentration (Table 3.3.7-3). The addition of 10 percent copper oxide to 10 percent sodium hydroxide decreases the SCC resistance of thermally trehted

• I-600 and I-690, and also modifies the SCC morphology with the presence of transgranular cracks. The exact mechanism responsible for these changes is not well understood, but it is believed to be related to an increase in the specimen potential, corresponding to a transpassive potential, which results in an alternate cracking regine. The specific osidizing specie and the ratio 1751c/0223c/020185:5 23 1

3-9 i

WESTINGHOUSE PROPRIETARY Ct. ASS 3 of oxidizing specie to sodium hydroxide concentration appear to p1ay..an '

important role. By lowering the copper oxide or sodiurs hydroxide concentration, the apparent deleterious effect on SCC resistance it eliminated. -

Mill annealed and thermally-treated I-600 and I-690 were also evalmted in a number of 8 percent sodium sulfate environments. The room t3nperature pH value, at the beginning of the test, was adjusted using sulfuric acid and ammonia. Test results are presented in Figura 3.3.2-3. As the pH is lowered, decreased SCC resistance for stil annealed and thermally-treated I-600 is observed, but thermally treated I-690 material did not crack even at a pH of 2, the lowest tested.

The primary eater SCC test data are presented in Figure 3.3.2-4. For the beginning of fuel c)cle water cnonistries,10 of 10 specimens of mill annealed I-600 exhibited SCC, while 1 of 10 specimens of thermally-treated I-60G had cracked. In the end of the fuel cycle water chemistries, 7 of 10 specimens of mill annealed (-600 exhibited SCC, while 3 of 10 specimens of thermally-treated I-600 had cracked. After 13,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> of testing, no SCC has been observed in the raill annealed or thermally > treated I-690 specimwns in -

.either test environment.

A Continuing investigation of the SCC resistance of I-600 and I-690 in primary water environments has shown mill annesled I-600 to be susceptible to cracking

'at high levels of strain and/or stress. Thermal treatment of I-600 in the carbide precipitation region greatly <mproves its SCC resistance. The performance of I-690, both mill arbealed Md thermally treated, demonGratEc highly Nsirable primary water SCC resistance, presumably due to alloy composition.

1

, 1751c/0223c/020185:5 24 3-10 y _ _ __ .. ..

WESTINGHOUSE PROPRIffARY CLASS 3 Table 3.3.2-1 ,

~

SUMMARY

OF CORROSION COMPARISON DATA FOR THERMALLY TREATED INCONEL A!.LOYS 600 AND 690 L Thermally treated Inconel 600 tubing exhibtts enhanced SCC and IGA resistance in both secondary-side and primary-side environments w. "n

' compared to the mill annealed condition.

2. Thermally treated Inconel 690 tubing exhibits additional SCC resistance compared to thermal treated Inconel 600 in caustic, acid sulfate, and -

primary water environments.

3. The alloy composition of Inconel 690 along with a thermal treatment provides additional resistance to caustic induced IGA.

4. TheadditionofIbpercentCu0toa10percentdeaeratedNaOHenvironment

~

reduces the SCC resistance of both themal treated I-600 and I-690. Lower concentrations of either Cu0 or NaOH had no effect, nor did additions of

~

Fe30 4 and SiO2 - '

5. Inconel Alloy 690 is less susceptible to sensitization than Inconel Alloy 600.

6. Inconel Alloy 600 ar.d 690 have comparable pitting resistance.

1751c/0223c/020185:5 25 3-11

--, . _ , - - _ _ _ . - - - , , - - . , - - - - - . , . , - , . , - ey--, -, , , - - . , --- , - - - -

m - - . - . .

WESTINGHOUSE PROPRIETARY' CLASS 3 Table 3.3.2-2 EFFECT OF OXIDIZING SPECIES ON THE SCC SUSCEPTIBILITV 0F THERMALLY TREATED !-600 AND I-690 C-41NGS IN DEMRATED CAUSTIC -

Temperature Exposure -

Environment (*C) Time (Hrs)_ I-600 TT I-690 TT 10 Percent NaOH + 316 4000 Increased Increased 10 Percent Cu0 -

Susceptibility

• Susceptibility

• 10 Percent NaOH + 332 2000 No effect No effect 1 Percent Cu0 -

1 Percent Na0H + 332 4000 No effect No effect 1 Percent Cu0 10 Percent NaOH + 316 , 4000 No effect No effect 10 Percent Fe304 10' Percent NaOH + 316 4000 No effect No effect 10 Percent $1'J 2 *

• Intergranular and transgranular SCC.

i l-i L

1751c/0223c/020185:5 26 3-12

i SCC GROWTH RATE FOR C-RINGS (150% YS AND TLT)IN 10% NaOH i Average Crack Growth i

Rate ( gm/Hr.) Temperature ( F)

, 550 575 soo 830 eso l I I -

1 I O 1600 MA l

e 1600 TT l

l m 1690 TT l-w 10-1 -

b

~

t

-2

! 10 __

= -

l

~

l I I I I 10 I I

- 290 300 .310 ' 320 330 340 350 i

69F Dw 10569 004 Temperature ( C) l Figure 3.3.2-1 1

l 1

1 l

'.Y.F~ .. ". l l

i .

s

--a, % 7'%,'

s -

'iI .y w

\

... 9, , I

)

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s -

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. j' ,) , -

% p.'

.,v. . , . , . .. ...,

-..\..

~

. 'c \

• t = '

, I,

... J

'. \ , . - .; -.

.i -

. .,:-:. : . . < i;

' I .

jtaso. ,

j .s .. ,

l I-600 MILL ANNEALED

. _ . . . . . . . _ _ _ . -- , .e s % - ,-

v

. n . . *:a-~%,'tV;

- .., 3..'.M. .,s n,.4m..f..C h. )^'C..W, ,s

.:i,.-

% .s .; g..

f.. .

l(.

. , . : y.4~

> s'f..

~. +~:-

• .w ,;,s. ',; .,.: 7 ..:

,.2..

t '.'.'&l..A.m.+,~.

- .  :~.y.?C: :cG .'.". ..c,

:< . l?r -i;  : Q *. '- : t . %,-.

I Y. .2 .,4' 2. ?.if... : . , . (. W. . ._ % y

. s.T'...;it. , % ~. .y I  ; .

-Q .;. '.?ls

. gp.

. , - . .,.,~. ,-n. ,.: ,.sv. . .%.

,. : ..,...t.

,7.3 r:L.n 5,.fJ t;.,2 n.

.,'  %. Gt p. '

1ssum 't

.. .' ,,l';.;,4 I-600 THERMAL TREATED Ib . , .,, 77,.-

~

L k g

. k.N .. nw .a.s.

hgs

-". c.'.An . .

~J w h 4-. N.s. Y%.

.vs -r-9,.

. 4 s-e .s. . .. eS 9g. ...e

,- ..f. e-l m Q- .p.r QJ. +Z::rc,2.s,. .m.. g.by?-+:*C;y--.1

.~h~.'4c.t!- 4:,,.

. : <. . < :. , : a.Acg.

@. . ~

.:. y.

~, o . ..* . . i. , 2,. .;. .,+ . .x.

.o, : .n

a. .-- c  : ,,

-,*: . . ., ,* .% .'.'.: ' . . r .s. ,f. ' ?. r.L'w. ). ggg

~' _

e.

I-690 THERMAL TREATED *. . **, g i LIGHT PHOTOMICROGRAPHS ILLUSTRATING IGA AFTER 5000 HOURS

! EXPOSURE OF INCONEL ALLOY 600 AND 690 C-RINGS TO 105 NaOH AT 332*C (630'F).

Figure 3.3.2-2 l

3-14

_J

SCC DEPiH FOR C-RINGS (150% YS)

IN 8% NA 2 SO 4 -

Maximum Crack Depth, gm

^

inches 1000 .

.040 80,000 ppm Na2SO4 800 (

'b.

IN 600 MA -

'032 5000 Hours M' LJt

, C-rings,150% YS fj i.n 600 -

.024 M

.r 400 -

.016 l lN 600 TT ~-

200 -

.008 IN 690 TT

• f k? -

i i

i

.- 6 W 2 3 4 5 6 7 10 Room Temperature, pH

........m, Figtare 3. 3. 2-3 8

i .

l -

REVERSE U-BEND TESTS AT 360*C (680*F)

BEGINNING OF FUEL CYCLE PRIMARY WATER Cumulative Number Cracked  %

10 -

MA eoo -

100 8 - -

6 -

4 50 g'

I 2

0 E

TT 890 MA eso -

, , g 0

E '

END OF FUEL CYCLE PRIMARY WATER Cumulative Number Cracked  %

10 - -

1m 8 -

f "A "

8 4

[ -

50 u,

, TTeoo l 2 -

_f 0 / TT soo uA eco- '

0 I I I I I l l  :

10,000 0 2000 4000 8000 8000 12,000 14,000 -

, , , , , , , , , , , , Exposure Time (Hours) -

Figure 3.3.2-4 ,

[

WESTINGHOUSE PROPRIETARY CLASS 3 3.3.3 UPPER AND LOWER JOINTS ,

All the data presented in Section 3.3.2 relative to the corrosion and stress

' corrosion cracking resistance of thermally treated Inconel Alloys 600 and 690

. are applicable to the sleeve.

The expansion processes for both the lower and upper joints involve a combinationof[

s '

e

]C The stresses in the sleeve, based on

- tube to tubesheet data, should be as shown at 8 and C on Figure 3.3.3-1, which are also judged acceptable, particularly in view of the corrosion resistance of the thermally treated sleeve material. Stress levels in the outer tube are also influenced by the expansion technique. For an outer tube expansion produced solely by [ ,

ja,c.e Confirmation that residual stresses at the tube 00 surface due to expansion were innocuous with regard to corrosion degradation was shown by accelerated controlled potential tests.

Two controlled potential tests were performed on HEJ's. [

3ac.e Electrochemically controlled test methods have been used previously to evaluate the SCC resistance of steen generator tubing N Maximum 1751c/0223c/020185:5 27 3-17

WSTINGHOUSE PROPRIETARY Cl. ASS 3 susceptibility to caustic SCC was observed when the electrode potentta'l of the Inconel Alloy 600 was held in [

)a,c.e C

]C tests,C-ringcontrol specimens were cut from the unexpanded and of the tube and stressed beyond ,.

yield. These control specimens were used to verify the aggressiveness of the environment. [

]**C These test data indicate that the residual stress levels on the 00 of the HEJ are low.

A suonary of the results for the various verification programs is presented in Table 3.3.3-1.

3.3.4 TEST PROGRAM FOR TE L0ER JOINT .

3.3.

4.1 DESCRIPTION

OF LOWER JOINT TEST SPECIMENS The tube /tubesheet mockup was manufactured so that it was representative of the tube /tubesheet joint (Figure 3.3.4.1-1) of the model 44/51 steam generators. Thetubewasthenexaminedwithafiberscope,(

Ja.c.e cleaned by swabbing, and re-examined with the fiberscope. Then the prefonned sleeve (Thermally Treated Inconel 600 or Thermally Treated Inconel 690) was inserted into the tube and the lower joint formed.

C 3a,c.e 1751c/0223c/020685:5 28 3-18 l-

,, ,a-.,-, -- 1- ~ , - - , - > -- - - - - - - - - - -

~.

E N.FWCc:z97,3pg;53,7((g333 TA8LE 3.3.3-1 DESIGN VERIFICATION TEST PROGRAM - CORROSION

~

Description of Issues Test Results

1. Corrosion and Stress

, Corrosion Cracking of

• Lower Joint J

d b

9 4

2. Corrosion and Stress Corrosion Cracking of

'HEJ 1681c/0216c/010985:5 23 3-19

- - . , - - - - , , - - - -- , ,-e,--.-,,.,y - , . . . - - , . , - - . , . , , - , - . ~ , . - - , - - + - - - -+_-.-w , - - - - - - , . - , .

WESTINGHOUSE PflOPRIETARY CLASS 3 nee a s

i Figure 3.3.3 1 i.

Location anct Relative Magnitude of Residual Stresses Inouced try Exoansson i

3-20 I

WESTINGHOUSE PROPRIETARY CLASS 3 720s.2s 1

l l

~ j l

a d

Figure 3.3.4.1-1 Lower Joint As-Rolled Test Specimen 3-21 '

,- - - - - ,, , ,,- - - . . - - - , , - . , ,r-

. ESTINGHOUSE PROPRIETARY CLASS 3 3.3.

4.2 DESCRIPTION

OF VERIFICATION TESTS FOR THE LOWER JOINT ,

The as-fabricated specimens for the Model 44 (as discussed in Section 3.3.1, -

Model 51 parsneters and conditions are bounded by Model 44 parameters and l

conditions) were tested in the sequence described below. Note that the tests ~

of tho' Inconel 690 sleeve are similar to' those. performed on the Inconel 600 sleeve except that the Steam Line Break (SL8) and E0P (Extended Operation

, Period) tests were not considered necessary based on previous results.

1. Initial leak test: The leak rate was determined at room toeperature, 3110 psi and at 600*F,1600 psi. These tests established the leak rate of the lower joint after it has been installed in the steam generator and prior ~

to long-term operation.

2.

The specimens were fatigue loaded for 5000 cycles.

3. The specimens were temperature cycled for 25 cycles.

4 The specimens were leak tested at 3110 psi room temperature and at 1600 '

psi 600*F. This established the leak rate after' 5 years of simulated normal operation (plant heatup/cooldown cycles) produced by steps 2 and 3. '

Several specimens were removed from this test sequence at this point and were subjected to the E0P Test. See Step 7, below.

5. The specimens were leak tested while being subjected to SL8 conditions.

6. The specimens were leak tested as in Step 1 to determine the post-accident leak rate.

7. The E0P test was performed af ter Step 4 for three as-rolled specimens.

. 1 1751cl0223cIO20185:5 29 3-22 w - - - - . _ _ - -

. WESTINGHOUSE PROPRIETARY CLASS 3 3.3.4.3 LEAK TEST ACCEPTANCE CRITERIA - .

Site specific or bounding analyses have been performed to determine the allowable leakage during normal operation and the limiting postulated accident condition. The leak rate criteria that have been established are based on Technical Specifications and Regulatory requirenents. Table 3.3.4.3-1 shows the leak rate criteria for thJ Model 51 steam generators. These criteria can .

be compared to the actual leak test result; to provide verification that the mechanical sleeve exhibits no leakage or slight leakage that is well within the allowable limits. Leak rate measurenent is based on counting the number of drops lqaking durin'g a 10-20 minute period. Conversion to volumetric

~

. measurement is based on assuming 19.8 drops per milliliter.

3.3.4.4 RESULTS OF VERIFICATION TESTS FOR LOWER JOINT The test results for the Model 44 (and Model 51, since Model 44 conditions bound Model 51 condit. ions) lower joint specimens are presented in Table 3.3.4.4-1. The specimens did not leak before or during fatigue loading.

After five years of simulated normal operation due to [

d

]C All of the three as-rolled specimens were leak-tight during the ExtendedOperatingPeriod(EOP) test.

For the Inconel 690 sleeve tests the following were noted:

Specimens MS-2 (Inconel 690 Sleeve): Initial leak rates at all pressures and at normal operating pressure following thermal cycling were [

3a,bc.e 1751c/0223c/020185:5 31 3-23

L .

WESTINGHOUSE PROPRIETARY CLASS 3 TA8LE 3.3.4.3-1 ..

ALLOWA8LE LEAK RATES FOR TYPICAL MODEL 51 STEAM GElERATORS (NormalOperation)

Allowable Leak Allowable Leak

, Condition Rate Rate per Sleeve Normal 0.35 gpe per steam 0.0002 gpm*

, Operation . generator 0.7 el/ min or

- ~

15.0 drops / min i

Limiting Leak Rate Leak Rate per Sleeve

• a,c.e Postulated Accident Condition -

(Stesaline Break) -

Based on 1946 sleeves per steam generator.

++ Standard Technical Specification Limit.

• • ( .

3a,c.e The analysis assumas primary and secondary initial inventories of luc 1/gu and 0.1vC1/ge of Dose Equivalent I-131, respectively. In addition, as a result of the reactor trip, an iodine spike is initiated which increases the iodine appearance rate in the primary coolant to a value equal to 500 times the equilibrium appearance rate.

1751c/0223c/020685:5 32 3-24 w

WESTINGHOUSE PROPRIETARY CLASS 3 Specimen MS-3 (Inconel 690 Sleeve): [ ..

3a,b,c.e Specimen MS-7 (Inconel 690 Sleeve): '[

, ja,b,c.e 3.3.5 TEST PROGRAM FOR THE UPPER HYBRID EXPANSION JOINT (HEJ) 3.3.

5.1 DESCRIPTION

OF THE UPPER HEJ TEST SPECIMENS

~Two types of HEJ test. specimens were fabricated for the Model 44 testing (as dicussed in Section 3.3.1, Model 51 parameters and conditions are bounded by model 44 parameters and conditions). The first type was a short specimen as shown in Figure 3.3.5.1-1. Some of these specimens were fitted with pots containing hard sludge to simulate the structural effects of sludge on the joint. The only type of sludge simulated in this program was hard sludge.

Soft sludge effects were bounded by the hard sludge effects and by the

'out-of-sludge conditions. [

Ja,b,c Any leakage was collected and measured as it issued from the annulus between the tube and sleeve. This type of specimen was used in the majority of the tests.

The second type of test specimen was a modification of the first type. It was utilized in the reverse pressure tests, i.e., for LOCA and secondary side hydrostatic pressure tests. As shown in Figure 3.3.5.1-2, the specimen was modified by [

1751cl0223c/020185:5 33 3-25

h

.. 3

+

e 4

e 5

9 mm N

=

8 0

as mm S

o E

8 m v y e a T F e e a P m s

y O. .

c. #

Q' S r:

• l=

W E

se

= e a .

"e te o

= I

_4 t

4 Go 9

6 4

h 2

t O e  % . m 4 g -

4 4

<Y 'j =

6 e =

s - - - -

= = = = . a. .t ,,

3-26 e

- + ' "

4t:*:'.:-:.:! ::* 2:: :2. ,n:3 e

I I

e .

- 4 m

8 -)

N J

. 1

. i o -

C =

0 ",

O -

- E

- 4 .

=

,e . g e

M -

m O

" 3 a

• c fa I E

E l 8 1 l -

m l 1

5

• l r -

g N =

+ 4 4 1

=

h h '

GP es 4

b so Y m k 6 =

. S

= ~ - , ,

.n e

=

d.

L p

== em en e

ee

a. a.

em g "

E E E E E E S I q

-27

9

h. . . -

3 e

4 e

9 e

e 7

g

- .i C w "

0 $

=

O

• e M $

E Mg'rI T.

n

-.=

e a

E n - g

. D x

- B S aat a

F I*

3 i

3-28 I

p - - -

, WESTINGHOUSE PROPRIETARY CLASS 3

~

la,,c The possible reverse pressure test leak path is shown in Figure 3.3.5.1-2.

Only specimens like Figure 3.3.5.1-1-(excluding the sludge conditions) were

' used in the I690 HEJ specimen fabrication as the effects of sludge had been established in the earlier model 44 tests.

3.3.5.2 DEJCRIPTIONOFVERIFICATIONTESTSFORTHEUPPERHEJ The verification test program for the HEJ was similar to that for the lower joint.

The HEJ was subjected to fatigue loading cycles and temperature cycles to

, simulate five years of nomal operation and the leak rate was determined before and after this simulated normal operation. For a number of the specimens, the leak rate was also detemined as a function of static axial loads which were bounded by the fatigue load. It is important to note that the fatigue load used in testing was that which was caused by a loading / unloading. However, the most stringent load on the sleeve / tube joint occurred at steady state operation. Hence, it was judged necessary to determine that the leak rate at static and fatigue conditions were cooperable. The upper HEJ specimens were also subjected to the loadings / deflections caused by a steam line break (SLB) accident and the leak rate was determined during and after this simulated accident. The upper HEJ was also leak tested while being subjected to two reverse pressure conditions, a LOCA and a condition which simulated a secondary hydrostatic test. An extended operation period test was also perfomed.

3.3.5.3 RESULTS OF VERIFICATION TESTS FOR THE UPPER HEJ The test results are presented in Tables 3.3.5.3-1 to 3.3.5.3-5.

1751c/0223c/020135:5 34 1 3-29

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

r~

h .. .

j

~'

O a

t i

l Hybrid Expansion Joint Test Soecimen (The t. ass Path, if Any Laskap Exists, is Shown by the Cotted Lines)

Figure 3.3.5.1-1 4 3-30

3 s .

e HEJ Specimens for the Reverse Pressure Tests.

The Leak Patn.

if Any Exists, is Shown by the Dorted Lines Figure 3.3.5.1-2 3-31 v a

WESTINGHOUSE PROPRIETARY Cl. ASS 3 As can be seen from Table 3.3.5.3-1, the HEJ's formed out-of-sludge,'i'.e., in D 'C

air,- had an average initial leak rate of approximately [ J at the normal operating condition of 600*F and 1600 psi. After five years of simulated normal operation due to 5000 fatigue cycles and 29 to 32 temperature cycles, the leak rate was [ ]b,c.e at the normal operating condition. Furthermore, for the E0P. test, f.e , after thirty-five years of simulated normal operation due to at least 175 temperature cycles (208 were

, actually used) and a total of 35000 fatigue cycles, the leak rate was

( ],b.c.e Table 3.3.5.3-2 contains data for upper HEJ's formed out-of-sludge. It -

Includes the same basic test data as Table 3.3.5.3-1, f.e., initial leak rate data. However, it includes static axial load leak tests, SLB and reverse ,

pressure tests in place of the fatigue and E0P tests included in Table 3.3.5.3-1. Five of the six specimens were leaktight at normal operating conditions during the initial leak test. The leak rate during static axial sleeve loads, bounded by the. fatigue load and caused by normal operating conditions was measured for four out-of-sludge HEJs. [

a

)b,c.e This leak rate was a negligible fraction of the per-sleeve limit of [ ]D'C

The results' For the post-SLS leak test, at the same temperature and pressure conditions, were similar to the during-SLB results [

]b,c.e This leak rate was a small Fraction of the post-SLS, per-sleeve limit of ( ]b,c.e The results for the out-of-studge HEJ reverse pressure test are shown in Table 3.3.5.3-2. For both the simu?ated LOCA and secondary side hydrostatic pressure test the leak rate was zero for the two specimens tested.

N e process used for forming HEJ's in sludge, in Tables 3.3.5.3-3 and 3.3.9.3 .t, ,as the reference crocess, per Table 4.0-1, 1151c/0223c/020685:5 35 3-32

.W ESTINGHOUSE PROPRIETARY CLASS 3 la.c.e The initial leak rate of the first group of upper HEJs formed in sludge was [ ['Catthenormaloperating condition as is shown in Table 3.3.5.3-3. Only one specimen had a

(- ' .

]'C

After exposure of the specimens to five years of

' simulated normal operation due to fatigue and temperature cycling, the average leak rate remained very low, [ ]b,c.e at the 600*F and 1600 psi condition.

t The results of the reverse pressure test for the in-sludge upper HEJs are also shown in Table 3.3.5.3-3. [

]a,b,c Itwas{ ]a,c.e for the simulated secondary side hydrostatic pressure test.

Table 3.3.5.3-4 also contains data for HEJs formed in-sludge. It incluces the same basic initial leak tests as Table 3.3.5.3-3. However, it includes axial load leak test and pcst-SLB leak tests in place of the fatigue and reverse pressure tests included in Table 3.3.5.1-2. All of the four specimens were leaktight during the initial leak test, per Table 3.3.5.3-4 Two specimens did not leak at any static axial load and two others did not leak until a compressive load of 2950 lbs was reached. However, the two leak rates at 2950 lbs were low, [ ] ,c.e for specimens Number PTSP-23 and PTSP-33, respectively.

-In general, the leak rates for static loads were approximately the same as for dynamic ~(fatigue) loads of the same magnitude. However, a specific set of specimens was not subjected to both types of loads.

1751c/0223cIO20685:5 36 3-33

[-

• WESTINGHOUSE PROPRIETARY CLASS 3 I

^

As shown in Table 3.3.5.3-4, the average leak rate for four in-sl0dge specimens during the SLB test was [

)b,c.e limit. The comparable value af ter the SLB test was [ ,

ja.c.e

[' The test data generated for the Inconel 690 saples is presented in Table '

j -

3.3.5.3-5. The following observations were noted:

-Specimen S-5 (Inconel 690): [ j a,b,c were found at initial leak testing it room temperature (R.T.). At 500'F, the leak rates reduced .

significantly and remained below L j"'D*C during a subsequent thermal cycling test. This specimen was formed with a tube dimetral bulge that was smaller than will probably be used in the field.

Specimens S-8 (Inconel 690); 255-8 and 255-13 (Inconel 625), b4, B-6, and l

B-7(Inconel 625/690 - U.740 in. Sleeve Dia.), and BA-11 f.Inconel 625/690-O.630 in. Sleeve Dia.): These seven specimens all exhibited [ ,

l ']a,c.e during the initial leak testing i

at R. T. In all cases, by the end of the testing, including thermal ,

cycling and fatigue in some cases, the leak rates had [

l Ja,c.e 1.3.6 TEST PROGRAM FOR THE FIXED-FIXED MOCKUP 3.3.6.1 DESCRIPf!ON OF THE FIXED-FIXED MOCKUP i

l The flued Fixed full scale neckup is shown in Figure 3.3.6.1-1. This mockup l simulated the section of the steen generator from the primary face of the tubesheet to the first support plate. The bottom plate of the mockup repre-sented the botton of the tubesheet, the middle plate simulated the top of the tubesheet and the upper plate simulated the first support plate. The tubes i

I were( l 'C into the bottom plate to simulate the tube /tubesheet i J011t ind 89to the upper plate to simulate a dented tube condt:fon. The term  ;

" fixed Fixed" was derived from the fact that the tubes were fleed at these two l l 1751c/0223c/020685:5 37 i

3-34 l

l

ESTINGHOUSE PROPRIETARY ELASS 3 Table 3.3.5.3-1 4

TEST RESULTS FOR MODEL 44 KJ'S FOR"DED OUT OF SLUDGE (Page I of 2)

(FATIGUE AND EXTENDED OPERATI000 TESTS INCt..)

s i

Specise

) No. -

1 i

PTA-46 w

i a

m PTA-47 l PTA-48 l -

PTA-52 PTA-53 4

j PTA-45 I. PTA-49 PTA-50 3

PTA-SI j PTA-54 1

{ Averages i

Note: Short specimens used for this test.

.f

ESTINGNON5E PROPRIETARV ELA55  :

Tahle 3.3.5.3-1 ( Cont. )

TEST RESUL15 FOR MODEL 44 KJ'S FORKO OUT OF SLHOGE (Page 2 of 2)

(FATIGUE AND EXTENDEO OPERAil0W TESTS INCL.) '

Specimen No.

PTA-46 y PTA-47 5 PTA-48 PTA-52 PTA-53 PTA-45 PTA-49 .

PTA-50 PTA-51 PTA-54 Averages : -

(

, wr..-..5... w.. ::-: *r

. . *  ::v ..:=.t2 o

e f '

2 , '

. 1d -

em -

=

a'I .

• E a

w i ; -

N a3

~

m' -

a M . -

e *9 9 O I*

e ,a E g O .

• 5 h

+

b

.n = 1 c I 3 E- - - 6 y

C1 '

t 5 6 I w. 4

- - S

~ m 1 g- x .

2 5 -

• d

~

I kg

== 3 e.

e. e se en 4.

=h u

2:

t ,, - 4 T -

2

a. $. <. <.e * .

e, et at a-Wa. W 4 e a= er W d asm =*

e. e- e- 9 == )

se W9 Gn Gn Gn Gm Gm & 4 S em .%m l l

l 3-37

_. . . _ . . _ , , , , w. --

-e n -~ - - - ' * - - - - - - - " " - - - - - ~ - ' " - - - * - ~ ~ ^ ' " ' ^ - ~ - ' - - ' " ~ ' ' " " ~ ~ ' ~

, e m.,

'~

l 7 i

O ESTilIGHDW5E PROPRIETARV (LASS .3 E

e E' TABLE 3.3.5.3-2 (Cont.. ) -

g .

I TEST RE5ul.T5 FOR siOBEL 44 KJ'S FORKO f4T Of SL*JpSE (Page 2 ef 21 f -

l (STATIC Atiti LOO LEAK TEST. SLB A4D KWRSE PKSSURE.iEST li1CL.)III l

l l -

Leak Rate After8tt Leak Rates Smelag Reverse Pressere Tes'..

l Average Leak Rate , Acclaient Csesi!Rien l

Sect. Mary flydre-Test During a Feedline (Room Temp.) (6dgi'F) l static P;wssure Less of Coolant Specimen Greek Accident. 1600 2400 !d00 2400 Test, h em Temp.

f Blo. Accident 60G*F. 1600 psi psi p:0 psi psi

! 135G ps9 545'F. 1050 pst

! y -

I w PTA-55 PTA-56 PTA-GF PTA-58 .

PTA-5g j PTA-61 1

• i

, Averages: .

]

i I -

J

• Specimen was modified to be tested under reverse pressures.

1 Short specimens dsed for tiils test.

) '

(1) All leak rates are in dropsAsinnte.

l

o; WEI*:'.G-:.!! ::::::t ::. ;,::: 3

i. ,

S 2

4 O e

~

M as s

I!

=3 es 8

a f .

1 I.I.

e f*l *E -

c4 ,m g

, as

- s -

4

.c 2a

' 9 33 I*

WI 5:I

=

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5

=

L-2 ft i

i 1

e.

!1 2 #}

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3-39 i

, WESTINGHOUSE PROPRIETARY CLASS 3 TA8LE 3.3.5.3-3 (cont.) ..

TEST RESULTS FOR MODEL 44 HEJ'S FORMED IN SLUDGE

. (FATIGUE AND REVERSE PRESSURE TESTS INCL.) (CONT)

. Leak Rates During Reverse Pressure Tests (drops / min.)

3: Test Secondary Hydrostatic Loss of Coolant Specimen Pressure Test, Accident No. Room Tsup./1350 psi 545'F/1050 psi PTSP-22 - -

PTSP-24 - -

PTSP-25 - -

, PTSP-28 - -

PTSP-29 -

PTSP-30 - -

PTSP-31 0 0

• PTSP-32 - -

PTSP-34 - -

a PTSP-35 - -

PTSP-36 - -

PTSP-37 - -

PTSP-38 - -

l PTSP-39 - -

! PTSP-40 0 0 l

l l

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WESTINGHOUSE PROPRIETARY C1. ASS 3 locations. There were thirty-two tubes in two clusters of sixteen. A' sludge sieslant composed of alumina was formed around one cluster of sixteen. '

Sleeves [

]**C long were installed in the tubes by [

-]a.c.e Each tube was perforated between the upper and lower joints to simulate tube degradation and thereby provide a primary-to-secondary leak path. End plugs were welded to the tubes to permit '

pressurization with water. ,

s No fixed fixed mockup tests were performed on the 1690 samples baseo on the resultsoftpeearliertestsperformed.

3.3.

6.2 DESCRIPTION

OF VERIFICATION TESTS FOR THE FIXED-FIXED MOCXU The fixed fixed mockup was used first to verify the full length sleeve installation parameters and tooling. It was then used to measure the leak rate of the lower joint, and upper HEJ. This leak rate was determined with the

• sleeve installed in a tube fixed at the tubesheet and dented at the first support plate, i.e., for the fixed-fixed condition.

3.3.6.3 RESUI.TS OF VERIFICATION TESTS FOR THE FIXED-FIXED

• MOCXUP Table 3.3.6.3-1 contains leak test results recorded for full length sleeves formed and tested in-situ, in the fixed-fixed mockup, in-sludge and out-of-studge (see Figure 3.3.5.3-3). All of the roon temperature initial leak tests produced [

ja,b,c These initial leak rate results were similar to the initial leak rate results j in which the short specimens were structurally unconstrained during' forming of I the upper HEJ. Therefore, it was concluded that the results of the other several tests performed only on short specimens would be similar if the test had been performed in-situ, in the fixed / fixed mockup. During the pre-test evaluation, it was determined that the fixed / fixed mockup duplicated the most 1751c/0223c/020685:5 39 3-43

MINGHOUSE PROMllETARY CLASS J . . ,

m as

+

Fimed. Fined Mockup-HEJ (For the HEJ fn-Situ Leek Tests.

the Lask Patn,if Any Esists, is Shown by tne Dotted Lines)

Figure 3.3.6.1-1 3-44

WESTINGHOUSE PROPRIETARY CLASS 3 l

l stringent structural loading conditions for sleeves. Therefore, it was j concluded that all of the testing with short specimens was valid. Because the model 44 loads encompassed the model 51 conditions, this testing is considered applicable to model 51 units also.

3.3.7 -EFFECTS OF SLEEVING ON TUBE-TO-TU8ESHEET WELO

, The effect of hard rolling the sleeve over'the tube-to-tubesheet weld was examined in the sleeving of 0.750 inch 00 tubes. Although the sleeve installation roll torque used in 0.750 inch tube.s is less than a .875 inch 00 tube, the radial forces transmitted to the weld would be comparable. ,

Evaluation of the 0.750 inch tubes showed no tearing or other degrading effects on the weld after hard rolling. Therefore, no significant effect on the tube-to-tubesheet weld is expected for the larger 0.875 inch OD tube configuration.

a e

1751c/0223c/020685:5 40 3-45

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3-46

. WESTINGHOUSE PROPRIETARY CLASS 3 3.4 ANALYTICAL VERIFICATION, 3.

4.1 INTRODUCTION

This section contains the structural evaluation of the sleeve and tube '

assembly with HEJ, sleeve material-1690 or 1600 and sleeve length [ ]C

in, relation to the requirements of the ASE Boiler and Pressure Vessel Code,Section III, Subsection N8, 1983 Edition [ Reference 1]

The analyses include primary stress intensity evaluations, maximum range of stress inte,nsity evaluations, and fatigue evaluations for various mechanical and thermal conditions which umbrella the loading conditions specified by the ~

Westinghouse Equipment Specification G-677164,12/18/69, Revision 1

[ Reference 5], Westinghouse Equipment Specification Addendum No. 677030, 11/12/73, Revision 3 [ Reference 6], and Westinghouse Equipment Specification Addendum No. 952404, Revision 1,3/21/75[ Reference 7].

3.4.2 C0190NENT DESCRIPTION

, The general configuration of the sleeve-tube ' assembly with HEJ is presented in Figure 3.4.2-1. ,

The critical portions of the sleeve-tube assembly are the two joints, the upper Hybrid Expansion Joint (HEJ) ar.d a mechanical lower joint, and straight sect. ions of the sleeve and tube between the two joints. Past analytical experience indicates that upper joint stresses are more limiting than lower joint stresses. A detailed stress evaluation of the [ ]a,c.e 3),,,, ,,, ,

therefore perfomed for the upper joint only. Finite element models were developed to represent the upper joint area. The tolerances used in developing the models were such that the maximum sleeve and tube outside disneters were evaluated in combination with the minimum sleeve and tube wall thicknesses. This allowed maxinum stress levels to be developed in the roll transition regions.

1751c/0223c/020185:5 41 3-47

,--nn---w,---- - , . -- - - -

r WEIT.ING*iCUSE PilCFRIETIRY C'Jr.2 3 s

Figure 3.4.2-1. Installed Sleeve with Upper Hybrid Expansion Joint Configuration 3-48

WESTINGHOUSE PROPRIETARY CLASS 3 3.4.3 MATERIAL PROPERTIES -

The sleeve material is Inconel 690 or Inconel 600. Both sleeve materials Inconel 690 and Inconel 600 are covered by ASE Code' Case N-20 (Reference 8].

The tube material is58-163 (Inconel 600).

An air gap was included between the tube and sleeve below the HEJ. Although this space could be filled with secondary fluid in the event of a discontinuous (or leaking) tube, assning the physical properties of air for these elements is conservative for the thermal analysis. Primary fluid physical properties were used for the gap medin above the HEJ.

All material properties used in the analyses were as specified in the ASME Soiler and Pressure Vessel Code,Section III, Appendix 1 [ Reference 4] and CodeCases(Reference 8].

3.4.4 CODE CRITERIA ,

The ASE Code Stress Criteria which est be satisfied are given in Tables 3.4.4-1 and 3.4.4-2. '

a 3.4.5 LOADING CON 0!TIONS EVALUATED The loading conditions are specified below:

1. Design conditions

a. Primary side design conditions P = 2485 psig T = 650*F

b. Secondary side design conditions P = 1085 psig

• T = 600*F 1751c/0223cl020185:5 42 3-49

}s,** -

. .. ... .. . . ;,, j; J.

. TABLE 3.4.4-1 D17tRf A' FOR PRIMARY STRES5 INTEN5fTY EVALUATION '

(5LLEVE1 .,

9 4

0 e

o e

9 9

O O

e 3-50

..... 3 TABLE 3.4.4-2 CRITERIA FOR PRIMARY STRE!$ INTEN!!TY EVAlt!ATION (TUBE) 6 S

6 l 0 e

9 0

e.

4 9

e 6

3 51

, W STINGHOUSE PROPRIETARY CLASS 3

c. Maximme primary to secondary pressure differential - 1600 ps,ig. -

T = 650*F

d. Maxique secondary to primary pressure differential - 670 psig, T - 650*F -

2. Full load steady state conditions are:

Primary side pressure 2235 psig d

Hot leg temperature = 599.1*F Cold leg temperature - 535.5*F 5econdary side pressure = 735 psig Feedwater touperature = 427.3*F -

Steam temperature . 510.8'F Other operating conditions are specified in Table 3.4.5-1.

3.4.6 METH005 0F ANALYS!$ .

Using the WCAN (Reference 2] finite element analysis progaae, stress ~

components were taken directly free the analysis of finite element models of the tube-sleeve assembly. Separate unit pressure runs and thermal transient '

runs were first made and then properly cod ined with the WCEVAL (Reference 3]

Program.

3.4.6.1 MODEL DEVELOPMENT A finite elemnt model was developed for evaluating the sleeve design.

t l

Some significant considerations in developing the model are:

1. Mechanical roll fixities between the sleeve and tube at the hard I

roll regions were achieved by using the same nodal numbers for the sleeve and tube interface. .

, 2. By varying the P:oundary conditions at a specified region of the l model, conditions of either an intact tube or discontinuous tube i were steulated.

I 1751c/0223c/020185:5 43 3-52 l -

i

)'. p. .. . . . .' . .! . . .: ."..':7,*.7,Y CU,;S3 TABLE 3.4.5-1 OPERATING CONDITIONS NO. OF OCCURRENCES CON 0!T!0N -

TO BE ANTICIPATED f NORMAL OPERATING CONDITIONS .

Plant Heatup 200 Plant Cooldown 200 Plant' Loading 55 Minute 18,300 -

Plant Unioading 5% Minute 18,300 Small Step Load increase 2,000 Small Step Load Decrease 2,000 Large Step Load Decrease 200 Hot Standby Operations 18,300 Turbine Roll Tett 10

, Steady State Fluctuations =

UPSET CONDITIONS Loss of Load 80 Loss of Power 40 Loss of Flow 80 Reactor Trip from Full Power 400 FAULTED CONDITIONS Reactor Coolant Pipe Break 1 Steam Line Break 1 Feed Line Break I TEST CONDITIONS Primary Side Hydrostatic Test 5 Secondary Side Hydrostatic Test 5 3-53

. WEST!lNiHOUSE PROPRIETARY Ct.A55 3

3. The interface nodes along the upper and lower hydraulic expansion regicas of the HEJ were coupled in the radial direction for temperature and thennel stress runs. The interface nodes along the lower hydraulic expansion region were coupled in the radial direction for pressure stress runs in the case of tube discontinuous.

The element types chosen for the finite element analysis were the ,

following WECAN [ Reference 2] elements:

a,c.e l

n 2.- All the element types are quadratic, having a node placed in the

, center of each surface in addition to nodes at each corner.

3.4.6.2 THERMU. ANAL.YSIS t

The purpose of the thermal analysis is to provide the temperature distribution needed for thennal stress evaluation.

Thermal transient analyses were performed for the following events:

Small step load increase Sas11 step load decrease

• Large steo load decrease Hot standby operations 1

1.'51cIO223c/020685:5 44 3-54 T

n hf s

,,-r , , , , . + - - . , , . . . .- . ..,,-.-,_,.,.._..~,..,.-----e.._..- .-~_...-...-..--.--,-___.-.--4 - - - - -

, WESTINGHOUSE PROPRIETARY CLASS 3 Loss of load Loss of power loss of secondary flow Reactor trip from full power The plant heatup/cooldown, plant loading / unloading ann steady fluctuation events were considered under thermal steady st=% conditions.

8 The finite element types chosen for the thermal analysis were STIF58 and STIF68.

0 In order to perform the WECAN thermal analysis, boundary conditions consisting of fluid temperatures and heat transfer coefficients (or film coefficients) for the corresponding element surfaces are necessary. The conditions considered in the thermal analysis are based on the following asseptions:

The temperature induced stresses are most pronounced for sleeves in the hot leg (where the temperature difference between the primary and secondary fluids is a maximum) and therefore, only the hot leg sleeves were considered. This condition bounds the thermal stresses on the cold leg. <

The sleeves may be installed in any tube in the generator.- Thus, to be conservative, it is assmed that the sleeve to be evaluated is sufficiently close to the periphery of the bundle that it experiences the water temperature exiting the downcomer.

Special hydraulic and thermal analysis was performed to define the primary and secondary side fluid temperatures and film coefficients as a function of time. Both boiling and convective heat transfer correlations were taken into consideration.

1751c/0223c/020185:5 45 3-55

ESTINGHOUSE PROPRIETARY CLASS 3 1

3.4.6.3 STRESS ANALYSIS , , - ,

I A WECAN [ Reference 2] finite element model was used to determine the stress -

levels in the tube / steeve configuration.

Elements simulating the medium between the tube and the sleeve were considered as dummy elements. The element types employed were STIF53 and STIF56.

Based on the results demonstrating the applicability of a linear elastic analysis, thermally induced and pressure induced stresses were calculated separately and then codined to detemine the total stress distribution using i the W CEVAL computer program (Reference 3]. In addition, WECEVAL performs the -

stress categorization required for an ASE Boiler and Pressure Vessel Code, I Section III, stress analysis and for the couplete fatigue evaluation.

The criteria in the evaluation were those specified in Subsection N8 of the ASE Boiler.and Pressure Vessel Code [ Reference 13 Pressure Stress Analysis

• For superposition purposes, the WECAN model was used to detemine stress , '

distributions induced separately by a 1000 psi primary pressure and a 1000 psi secondary pressure. The results of these " unit pressure" runs were then

-scaled to the actual primary side and secondary side pressures corresponding to the loading condition considered in order to determine the total pressure stress distribution.

The two nodeling considerations in determining the unit pressure load stress distributions were tube intact and tube discontinuous. Therefore, the i

following unit pressure loading conditions were evaluated to determine the maximum anticipated stress levels induced by primary and secondary pressures:

Primary pressure - tube intact Primary pressure - tube discontinuous Secondary pressure - tube intact Secondary' pressure - tube discontinuous 1751c/0223c/020185:5 46 3-56

WESTINGHOUSE PROPRIETARY CLASS 3 The end cap forces due'to the axial pressure. stress induced in the tube away t from discontinuities were taken into consideration.

l Thermal Stress Analysis '

' The WECAN model was tised to determine the thermal stress levels in the

' tube / sleeve configuration that were induced, by the temperature distribution calculated by the thermal analysis. The times during the thermal transient solutions which were anticipated to be limiting from a stress standpoint were evaluated.

Combined Pressure Plus Thermal Stress Evaluation  !

4

' As mentioned previously, total stress distributions were determined by l combining the unit pressure and thermal stress results as follows:

' total " ' I'I unit primary pressure 4

P

+Msee . (') unit secondary pressure

• I'I thermal At any given point or section of the model, the program 'ACEVAL determines the total stress distribution for a given loading condition and categorizes that total distribution per the Subsection N8 requirements. That is, the total j

stress of a given cross-section through the thickness is cacegorized into membrane, linear bending, and non-linear components. These categorized stresses are then compared to Subsection N8 allowables.

. In addition, when supplied with a complete transient history at a given location in the model, the WECEVAL program dll calculate tne total cumulative

' fatigue usage factor per Code Paragraph NB-3216.2.

1751c/0223c/020185:5 47 3-57

I 1

7 5TINGHOUSE PROPRIETARY CLASS 3 3.4.7 RESULTS OF ANALYSES , , - -

Analyses were performed for both intact and discontinuous tubes. Fatigue and -

stress analyses of the sleeved tube assembly have been completed in accordance with the requirements of the ASE Boiler and Pressure Vessel Code,Section III. -

3.4.7.1 PRIMARY STP.ESS INTENSITY The umbrella loads for the primary stress intensity evaluation are given in Table 3.4.7.1-1.

The results of primary stress intensity evaluation for the analysis sections ~

are swenarized in Tables 3.4.7.1-2 and 3.4.7.1-3.

All primary stress intensities for the sleeved tube assembly are well within allowable ASE Code limits.

The largest value of the ratio " Calculated Stress Intensity / Allowable Stress Intensity" of [ -

l 3a,b,c

! 3.4.7.2 RANGE OF PRIMARY AND SECONDARY STRESS INTENSITIES

, Table 3.4.7.2-1 contains the pressure and temperature loads for maximum range of stress intensity evaluations as well as for fatigue evaluations.

The maximum range of stress intensity values for the sleeved assemblies are swunarized in Table 3.4.7.2-2.

The requirements of the ASME Code, Paragraph NS-3222.2, were met directly at all locations and required no further consideration.

1751c/0223c/020185:5 48 3-58 i

E-

. 3 TAELE 3.4.7.1-1 UMBRELLA PRES $URE LOA 05 FOR*

DE51GN. UP5ET. FAULTED. At:0 TE5T CONDITIONS CONDITIONS Desfon Design Primary Design < Secondary ~

MLs1}t, Loss of Load Loss of Power Loss of Flow .

Reactor Trip from Full Power Faulted .

Reactor Coolant Pipe Break Steam Line Break Test Primary $fde Hydrostatic Test j

Secondary Side Hydrostatic Test l

l i

l l

1 3-59

TABLE 3.4.7.1-2 RESilLTSDI_PillMARY_STRESSINTENSITYEVAtuALONS .

PRIMARY MEMBRANE STRESS INT [NSITY, P e

CALCULATED MAXIMUM ALLOWABLE OF STRESS ' STRESS RATIO INTENSITV. INTENSITY.

LOCATION CONDITIONS KSI CALCULATED S.I.

KSI M IlliTAlitt S.I. .

TUBE INTACT Sleeve Design Primary

• i i

Tube Design Secondary  !.

I Tulle DISCONTINUGUS o,

i Sleeve Primary Side .

P liydrustatic Test  !..

tw Tube 4

~

, O 4 I

. ,f.

• TABLE 3.4.7.1-3 RESULTS OF PRIMARY STRESS INTENSITY. EVALUATIONS PRIMARY MEMBRANE PLUS BENDING STRESS. bINTENSITY, P ,_+ P CALCULATED MAXIMUM ALLOWABLE OF STRESS STRESS INTENSITV, RATIO LOCATION, CONDITIONS INTENSITV, KSI CALCUL ATED S.I .

KSI _

ALLOWABTLY.C__

TUBE INTACT_ ,

• Sleeve Design Primary Tube Loss of Power Secondary Side I

Hidrostatic Test .

$ TUBE DISCONTINUOUS Sleeve Primary Side Hydrostatic Test Loss of Power Le Tube

~

t

J e

TAetE 3.4.7.2-1 PRESSURE AND TENERATURE LOADINGS FOR M4XINIM RAIIEE 0F siitT5 lhTill511Y AND FATIGUE EVAllRIl0lls

\

CASE PRE 550RE. P516 CON 0lilott IN E 11 0 . CYCLES THERNAL*

PRIMARY SECONDARY STRESSES Ambient As6 tent 1 200 0 0 0 Plant Loading **

Plant Heatup IPLLD 2 '- 18300 y Plant Cooldown 2235 1005 Steady. t = 0 ses S 2PLLD 3 ,18300

' Plant Unloading 2235 735 Steady, end

\

5saa11 Step Load Decmase 155LD 4 2000 2310 815 255L0 5 t = 30 sec 2000 2160 769 g . 150 sec Small Step Load lacmase 155LI 5 2000 2213 6 36 255LI 7 t = 50 sec 2000 2227 687 t = 185 sec  !

Large Step Load Dec mase ILSLO 8 200 2310 1017 2L5LD -9 t = 60 sec 200 2160 870 t = 480 sec Hot Standby Operations INSTB 10 18300 '2235 1005 t = 0 sec 2115TB 11 18300 2235 1005 t = 550 sec

a 4

, 1ABLE 3.4.7.2-1 .(con t)

PRES $URE AND TEMPERATURE LOAOlllG5 FOR MAXIMM RANGE OF STRESS INTENSITY AND FATIGUE EVALUATIONS CASE PRES $URE. PSIS CON 01 TION llADE 11 0 . CYCLES THEIMAL*

PRIMARY SECONDARY STRESSES Turbine Roll Test 1TRT 12 10 2235 1935 0 2TRT 13 10 1875 525 0

- 1 Loss of Load . u ILLO 14 80

2585 1070 2LLO 15 t = 12 sec '

.- 80 1600 1070 -

t = 100 u c i

[

Loss of Power ILPW 16 3

40 2060 1110 2LPW 17 t = 125 sec 40 2485 1110 t = 2000 sec Loss of Flow 5 ILFW 18 80 2210 722

{ 2LFW t = 20 sec 19 80 1860

} 930 t . 140 sec; i

! , Reactor Trip from \a 1RTR 20 400 Full Power 2085 876 t = 10 sec 2RTR 21 400 1815 970

) Steady State t = 70 sec ISFL '22 i Fluctuations 2SFL 23 lof 10 2335 755 Steady 2135 715 Steady Primary Side Hydrostatic

) Test i PRilYDRO 24 5 3106 0 i 0 i

Secondary Side liydrostatic Test 4 SECHYDRO 25 5 0- 1356 0

, 'Ihennal sfilsses are given for the spectfic tiamo t ea-

TABLE 3.4.7.2-2

• RESULTS OF MAX pIM R_ANGE OF STRESS INTENSITV EVALUATION i

• CALCULATED ALLOWASLE MAXINUN MAXINIM LOAD CONDITION RATIO LOCATION RANGE OF S.I. RANGE OF S.I.

_ COMBINATION ESI CALCULATED 5.i.

KSI ALL(NASLE S.I.

TU8E INTACT -

?

Sleeve Ambient -

Reactor Trip Reactor Trip -- ,

Secondary Hydrotest Y

• Tube Ambient -

1 Reactor Trip TU8E DISCONTINUQUS

[

Sleeve Primary Hydrotest -

• Secondary Hydrotest Reactor Trip -

Secondary Hydrotest L,

Tube

.h Y

4 I

WESTINGHOUSE PROPRIETARY CLASS 3

. 1

'3.4.7.3 RANGE 0F TOTAL STRESS INTENSITIES -

Based on the sleeve design criteria, the fatigue analysis considered a design life objective of 40 years for the sleeved tube assemblies. Table 3.4.7.2-1, describes the transient conditions used in the fatigue analysis.

Because of possible opening of the interface between the sleeve and the tube

. along the hydraulic expansion regions, thee maximum fatigue strength reduction factor of 5.0 (N8-3222.4(3)) was applied in the radial direction at the upper

_Hard Roll Region interface node, in the case of tube intact; and additionally at the lower hard roll region interface node, in the case of tube discontinuous.

The results of the fatigue analysis for the sleeved tube assemblies are stannarized in Table 3.4.7.3-1.

All of the cumulative. usage factors are below the allowable value of 1.0 specified in the ASE Code.

8 i

1751c/0223c/020685:5 49 3-65 J ,

-y, - ; ~- rw -

1-

, WESTINGHOUSE PROPRIETARY CLASS 3 e

t 3.4.8 REcERENCES .

. 1. ASE Boiler and Pressure Vessel Code,Section III, Subsectic 1 NB,1983 Edition, July 1, 1983.

2. WECAN,'WAPPP and FIGURES II, F. J. Bogden Editor, Second Edition, May i 1981, Westinghouse Advanced System Technology, Pittsburgh, PA 15235.

i

3. J. M. Hall,. A. L Thurman, J. B. Truitt, " Automated ASME Stress Evaluation Program WECEVAL, The Proceedings cf the Fourth WECAN User's Colloqpium, Westinghouse, October 5,1979.

4 ASME Boiler and Pressure Vessel Code,Section III, Appendix I.

5. Equipment Specification G-677164, Westinghouse, July 10, 1959, Revision 1, December 18, 1969.

l

6. Equipment Specification Addendum No. 677030,' Westinghouse, April 17, 1968, Revision 3, November 12, 1973.

. I

7. Equipment Specification Addendum No. 952404, December 21, 1973, Revision 1, March 21, 1975.

8. ASE Boiler and Pressure Vessel Code, Code Cases, Case N-20,1983

' Edition, July 1,1983.

9. N. Pessall, G. P. Airey, and 8. P. Lingenfelter, "The Influence of Thermal Treatment on the SCC Behavior of Inconel Alloy 600 at Controlled Potentials -in 10 percent Caustic Soda Solutions at 315*C," Corrosion, Vol. 35, 1979.

10. G. P. Airey, " Optimization of Metallurgical Variables to Improve the Stress Corrosion Resistance of Inconel 600". Final Report under EPRI

• Contract No. RP621-1, March 1980.

l l

l 1751c/0223cIO20185:5 50 l 1

!. l 3-67  !

l l

V I L

u

, , WESTINGHOUSE PROPRIETARY CLASS 3

11. G. P. Airey, A. R. Vaia, "A Caustic SCC Evaluation of Thermally Treated Inconel Alloy 600 Steam Generator Tubing," Presented at MICON 82 Symposium, Houston, Texas. .

12. G. P. Airey, A. R. Vaia, " Metallurgical and Environmental Parameters that

• Affect the High Temperature Water SCC Perfomance of Inconel Alloy 600 "

Presented at the EPRI Workshop, June 1981.

t '

s i

I 1751c/0223c/020185:5 51 l 3-63 5

1

, WESTINGHOUSE PROPRIETARY CLASS 3

. 1 3.5 'SPECIAL CONSIDERATIONS ,

3.5.1 FLOW SLOT. HOURGLASSING ~

~ Along the tube-lane, the tube support plate has several long rectangular flow slots that have the potential to deform into an " hourglass" shape with significant denting.' The effect of-flow-slot hourglassing is to move the neighboring tubes laterally inward to the }ube lane from their initial i

positions. The maximum bending would occur on the innermost row of tubes in

-the center of the flow slots.

e

~

3.5.1.1 EFFECT OF BURST STRENGTH The effect of bending stresses on the burst strength of tubing has been studied. Both the axial and circumferential crack configurations were i investigated. [

3a,ef 3.5.1.2 EFFECT ON STRESS CORROSION CRACKING (SCC) MARGIN Based on the results of an ongoing caustic corrosion test program on mill-annealed tubing, the bending stress magnitude due to flow-slot hourglassing is judged to have only a small effect, if any, on the SCC resistance margins. Two long term modular model boiler tests have been conducted to address the effect of bending stresses on SCC. No SCC or IGA was detected by destructive examination. It is to be noted that thermally treated

~

Inconel 600 and Inconel 690 have additional SCC resistance compared to mill annealed Inconel 600 tubing.

'3.5.1.3 EFFECT ON FATIGUE USAGE In addition to the above two considerations, one should also consider the effect of the hourglassing-induced bending stresses on the fatigue usage ~

factor of the sleeve. This is included in the fatigue analysis by recognizing that the stress induced by this motion is a mean stress. Mean stress effects

• are included in the S-N fatigue curve used in the analysis, hence hourglassing induced bending stresses are included in the fatigue analysis.

! 1751c/0223c/020185:5 52 3-69

I .

, WESTINGHOUSE PROPRIETARY CLASS 3 3.5.2 TU8E V!8 RATION ANALYSIS ,

Analytical assessments have been performed to predict nodal natural -

frequencies and related dynamic bending stresses attributed to flow-induced vibration for sleeved tubes. The purpcse of the assessment was to evaluate -

the effect on the natural frequencies, amplitude of vibration, and bending stress due to installation of various lengths of sleeves.

Since the level'of stress is significantly below the endurance limit for the tube material and higher natural frequencies result from the use of a sleeve / tube versus,an unsleeved-tube, the sleeving modification does not contribute to cyclic fatigue. ~

. 3.5.3 SLUDGE HEIGHT THERML EFFECTS In general, with at least 2.0 inches of sludge, the tubesheet is isothemal at the bulk temperature of the primary fluid. The net effect of the sludge is to reduce tube /tubesheet thermal effects.

3.5.4 ALLOWA8LE SLEEVE DEGRADATION f 4 Minimum required sleeve wall thickness, tr , to sustain normal and accident condition loads are calculated in accordance with the guidelines of Regulatory

- Guide 1.121, as outlined in Table 3.5.4-1. In this evaluation, the surrounding' tube is assumed to be completely degraded; that is, no design credit is taken for the residual strength of the tube.

The sleeve material may be either themally treated Inconel 600 or thermally treated Inconel 690. It has been shown that the properties of Inconel 600 are very similar to those of Inconel 690. In particular, the yield strength and ultimate strength are very similar.

The properties of I-600 were used in these at:alyses because the data base for -

I-600 is larger than the data base for I-690, thus allowing the use of a smaller tolerance factor.

1751c/0223c/020185:5 53 3-70

4

• 1 WESTINGHOUSE PROPRIETARY CLASS 3 Table 3.5.4-1 .

REGULATORY GUIDE 1.121 CRITERIA

1. Normal Operation Determine tr, minimum required sleeve wall . thickness.

a. Yield ,

1 -

Criterion: S1 y 39.59 ksi loading: Pp - 2250 psia

, Ps - 750 psia AP = 1500 psi AP . R a,c.e Hence, tr"5 Y

- 0.5 (P p

+P)=[ s

] inch 4

. which is [ ]a.c e percent of the nominal wall thickness.

b. Ultimate

• Criterion: Sui 90.58 ksi Loading: P, - 2250 psia Ps - 750 psia aP = 1500 psi Hence, tp=3 =[ ] inch a,c.e

[-0.5(P p+P) 3 which is [ ] a,c e percent of the nominal wall thickness.

2. Accident Condition loadings

a. LOCA + SSE The major contribution of LOCA and SSE loads is the bending stresses at the top tube support plate due to a combination of the support motion, inertial loadings, and the pressure differential across the tube U-bend resulting from the rarefraction wave during LOCA. Since -

the sleeve is located below the first support, the LOCA + SSE bending stresses in the sleeve are quite small. The governing event for the sleeve therefore is a postulated secondary side blowdown.

1751c/0223c/020685:5 54 3-71 f

6

- , - , .,.,-w..,.-

. , ,_...m, ,- ,---.. ,,--...m,n . . - - - - - - , , , , - . - , , , . , , , , , - , . . , . . . , - ,,,,n -,-

i. - .

.- WESTINGHOUSE PROPRIETARY CLASS 3 Table 3.5.4-1 (cont.) ..

- b .' FL8 + SSE -

The maximum primary-to-secondary pressure differential occurs during '

a postulated feedlir.e break (FLS) accident. Again, because of the sleeve location, the SSE bending stresses are small. Thus, the

' governing stresses for the sinimum wall, thickness requirseent are the pressure membrane stresses.

Criteriop: P ,< smaller of 0.75, or 2.45 ,i.e. 63.41 ksi Loadings: P, = 2650 psig P, e 0 aP = 2650 R

wence, e, - ;.r;ud .d ,1,p . ,s3-t .

j' c

• or, [ la.c.e ,,pe_,,g of ,,,4,,; ,,gg,

3. Leak.8efore-8reak Verification -

The leak-before-break evaluation for the sleeve is based on leak rate and burst pressure test data obtained on 7/8 inch 00 x 0.050 inch wall and 11/16 inch 00 x 0.040 inch wall cracked tubing with various amounts of:

unifore thinning simulated by machining on the tube 00. The margins to burst'during a postulated SL8 (Steamline Break Accident) condition are a function of the mean radius to thickness ratio, based on a maximum permissible leak rate of 0.35 gpm due to a normal operating pressure differential of 1500 psi.

Using a mean radius to thickness factor of 9.5 for the nominal sleeve, the current Technical Specifications allowable leak rste of 0.35 gpe, a SLB pressure differential of 2560 psi, and the nominal leak and nominal

- burst curves, a 25 percent margin exists between the burst crack lengtn and the leak crack length. For a sleeve thinned 54 percent through wall -

over a 1.0 inch axial length, a 17 percent margin to burst is demonstrated. Thus the leak-before break behavior is confirmed for

/ .

unthinned and thinned conditions.

1751c/0223c/020685:5 55 3-72

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- - - * * - ,,.4 ,, - . - - - _ , - - , - , , , , , .,- - _ _ ~ , . - . _ . - , - -

1

, , WESTINGHOUSE PROPRIETARY CLASS 3 3.5.5 EFFECT OF TUBESHEET/ SUPPORT PLATE INTERACTION .. i

' Since the pressure is normally higher on the primary side of the tubesheet than on the secondary side, the tubesheet normally becomes concave upward.

Under this condition, the tubes protruding from the top of the tubesheet will rotate from the vertical. This rotation depends on the boundary condition

. assumed for the edge of the tubesheet. Previous calculations of the tubesheet deflection using a finite element model of,the tubesheet whic'h includes the

' effects of the adjacent channel-head and the stub barrel resulted in a plot that checked with the theoretical deflection fonsula for circular plates with fixed edges, provided that the shear deflection is included.

. ~

Calculationsshowedthat[ 3a,c.e This stress was added to the cyclic stress in the fatigue evaluation. Note that this stress can be ratioed to account for different ap's that occur in different events. However, the seismic stress, as shown above, is not critical to the fatigue usage which was found to be low. .

3.5.6 COWREHENSIVE CYCL.IC TEST A

The Comprehensive Cyclic Test was designed to simulate the loadings produced by the heatup/cooldown and load / unload transients on the upper tube-to-sleeve joint. This test was initially intended to be used in conjunction with the Axial Shear Fatigue Test (a 5,000 cycle fatigue test) to evaluate the sealing integrity of the tube-to-sleeve joint after the application of cyclic loadings. They also would provide experimental confirmation of the capability of the joints to withstand fatigue loadings.

Based on analytical comparisons, the fatigue test produced fatigue that was substantially greater than that which would have been produced in the Comprehensive Cyclic Test. Also, the fatigue test produced more fatigue than was calculated to occur due to the inservice transient conditions. Therefore,

• it was determined that the Comprehensive Cyclic Test was not needed in addition to the fatigue test in determining the fatigue integrity of the tube-to-sleeve joint.

1751c/0223c/020185:5 56 3-73

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t WESTINGHOUSE PROPRIETARY Ct. ASS 3 3.5.7 EVALUATION OF OPERATION WITH FLOW EFFECTS OUE TO SLEEVING ..

An ECCS performance analysis considering 5 percent uniform steam generator tube plugging, SGTP, has been completed for the forthcaning Westinghouse fuel reload of the Prairie Island Units. This safety analysis assumed up to 5 *

. percent tube plugging in the stems generators of either plant and took credit for the current 2.28 value of total core peaking factor. This study and the

, corresponding non-LOCA study are considered applicable for the stems generator sleeving program as regards Westinghouse-supplied fuel. . The accidents evaluated include LOCA and non-LOCA transients as well as consideration of the effects on the nuclear design and thermal-hydraulic performance with the existing plant reactor internals. For the accidents considered in that study, the core and system parameters either remained within their proper limits (i.e., peak clad temperature, ONE, RCS pressure, etc.) or the impact of the additional tube plugging was shown to be negligibly small.

Inserting a sleeve into a staan generator tube results in a reduction of primary coolant flow. The selected sleeving program at Prairie Island involves the 36 inch long sleeve. [ ~

ja.c.e

[ a,c.e l

3 1751c/0223c/020685:5 57 3-74

1 WESTINGHOUSE PROPRIETARY CLASS 3 Prairie' Island Unit 1 -

S/G 1 S/G 2 Maximum number of tubes to be sleeved 1,946 (57 percent) 1,946 (57 percent)

D '-

Equivalent Plugged Tubes 60 (1.8 percent) 60 (1.8 percent)

Existing Plugged Tubes 43 (1.3 percent) 18(0.5 percent) 3 (as of October, 1984)' . .

Total "mitvalent Plugged Tubes 103 (3.1 percent) 78 (2.3 percent) 4 Prairie Island Unit 2 S/G 1 S/G 2 Maximum number of tubes to be sleeved 1,946 (57 percent) 1,946 (57 percent)

Equivalent Plugged Tubes 60 (1.8 percent) 60 (1.8 percent) -

, Existing Plugged Tubes 46 (1.4 percent) 95 (2.8. percent)

~

(as of 0ctober, 1984) '

Total Equivalent Plugged Tubes 106 (3.2 percent) 155 (4.6 percent) '

-For the stema generators in either of the Prairie Island Units, 5 percent of j the total tubes (3388 tubes per S/G) equals 169 tubes plugged in any one steam generator. The ECCS analysis model is such that a uniform steam generator ,

tube plugging condition is modeled. The NRC staff has required that the LOCA l analysis for a plant with steen generator tube plugging models the maximum i tube plugging level present in any of the plant steam generators.

For the conditions presented above for Prairie Island 1, the limiting equivalent plugged tube condition in the two steam generators is 103 tubes, which provides margin of 66 tubes (169 minus 103) available for additional plugging (or any equivalent combination of sleeves and plugs) before exceeding the basis of the LOCA analysis with 5 percent SGTP. With a smaller number l 1751c/0223c/020685:5 58 3-75 i

, .. _ _ . _ . . _ . . . - _ . , _ _ . _ . _ _ . . . ,- __ _ _ ._ _ _ . . , _ _ _ . _ , _ . . .- _._.__,_._l

s

. WESTINGHOUSE PROPRIETARY CLASS 3 s

of sleeves,; the margin of tubes available for additional plugging.wduid be '

larger. With only 500 sleeves per steam generator,110 tubes (169 minus 59) would be available for additional, plugging. '

For. Prairie Island Unit 2, the limiting equivalent plugged tube condition in ~

i the two stesa generators is 155 tubes, which provides margin of 14 tubes (109 minus 155) available for additional plugging (or any equivalent combination of

, sleeves and plugs) before exceeding the basis of the LOCA analysis with 5 percent SGTP. With only 500 sleeves per steam generator, 49 tubes (169 minus 111) would be available for additional plugging. Accordingly, no ECCS results more adverse than ethose in the existing Westinghouse fuel safety analysis are ,

anticipated for equivalent tube' plugging projected to occur at the Prsirie

!sland Units with up to 1,946 sleeves per steam generator, given that the existing vessel internals remain in place.

The effect of sleeving on the non40CA transient analyses has been reviewed.

Analyses of the level of slesving~and plugging discussed in this report have

'shown that the Reactor Coolant System flow rate will not be less than the

' ~

Thermal Design Flow rate. The Thermal Design Flow rate.is that which is assumed in the non40CA safety analyses and is designed to be less than the

-minimum RCS flow rate.that could occur under normal or degraded condition %.

Since the reduced RCS flow rate is not less than the assumed flow rate (Thermal Design Flow), the non40CA safety analyses are not adversely impacted by this anticipated maxima amount of steam generator tube sleeving (1,946 sleeves per steau generator). The reduced RCS flow rate is within the bounds I of the Safety Analysis Report for non40CA transient analyses and causes no safety concerns. Any smaller number of sleeves would have less of an effect, in addition, as a result of tube plugging and sleeving, primary side fluid velocities in the stesu generator tubes will [ la,c,e The effect of

thisvelocity[ ]**C on the sleeve and tube has been evaluated i assuming a conservative limiting condition in which [ ]ac.e of the '

tubes are plugged. As a reference, normal flow velocity through a tube is approximately[ ]a,ce, for the unplugged condition. With 10 percent of the tubes plugged, the fluid velocity through an unplugged tube is

[ ]a.c.e ft/sec., and for a tube with a sleeve, the local fluid

~

velocity in the sleeve region is estimated at [ ]a,c.e ft/sec. This I l velocity [ ]"'C causes no safety concerns.

l 1751c/0223c/020685:5 59 3-76 )

e 7

l

)

1  !

WESTINGHOUSE PROPRIETARY CLASS 3

\

3.5.8 ALTERNATE SLEEVE MATERIALS As was mentioned above in Section 3.4.3, Inconel as a sleeve material is covered by the ASME Code Case N-20. The design stress intensity value S, for both materials 1690 and 1600 covered by the Case N-20 is identical (S,=26.6ksi). Therefore, for these, materials, Prisery Stress Intensity and Maximum Range of Stress Intensity allowables are similar. Only pressure stresses were considered when calculating Primary Stress Intensity. The maximum Primary Membrane Stress Intensity was found at the analysis section on the straight portion of the tube. Hence, the ratio " Calculated Maximum Primary Membrane Stress Intensity / Allowable Stress Intensity" which was critical for the minimum sleeve thickness of [ ]a,c.e does not ~

depend upon the sleeve material (Inconel 690 or Inconel 600). Thermal stress, and hence maximum range of stress intensity and fatigue usage factor, could depend upon the mechanical properties of the sleeve material. The modulus of elasticity of Inconel 600 is higher than that of Inconel 690 by ~7 percent.

However, the coeffici,ent of thermal expansion of Inconel 690 is higher than that of Inconel 600. Past analytical experience indicates that the a-mismatch between 1690 and 1600 as sleeve material has a significant effect on thermal stress. Therefore, the results of the Maximum Range of Stress Intensity and Fatigue Evaluations for the sleeve and tube assembly with I690 as .the sleeve material are conservative relative to those which would be calculated with 1600 as a sleeve material.

1751c/0223c/020185:5 60 3-77 m -

1 idESTINGHOUSE PROPRIETARY PLASS 3 4.0 PROCESS DESCRIPTION -

The sleeve installation consists of a series of steps starting with tube end preparation (if required) and progressing through sleeve insertion,. hydraulic expansion at both the lower joint and upper Hybrid Expansion Joint (HEJ) regions,[ '

]C and joint inspection. The sleeving sequence and process are outlined in Table 4.0-1.

3 All these steps are described in the following sections.

4.1 TUBE PREPARATION e

There are two steps-involved in preparing the steam generator tubes for the sleeving operation. These consist of light rolling (as required) at the tube end and tube honing.

4.1.1 TUBE END ROLLING (CONTINGENCY)

If gaging or tube inside diameter measurements indicate a_need for tube end rolling to provide a uniform tube opening for sleeve insertion, a light

' mechanical rolling operation will be perfonned. This is sufficient to prepare the mouth of the tube for-sleeve insertion without adversely affec' ting the

~

original tube hard roll or the tube-to-tubesheet weld. Tube end rolling will be performed only as a contingency.

Testing of similar lower joint configurations in model 27 steam generator

-sleeving prograns at a much higher torque showed no effect on the tube-to-tubesheet weld. Because the radial forces transmitted to the tube-to-tubesheet weld would be much lower for a larger model 51 sleeve than for the above test configuration no effect on the weld as a result of the light roll is expected.

1751c/0223c/020685:5 61 4-1

4 WESTINGHOUSE PROPRIETARY CLASS J TA8LE 4.0-1 l I

SLEEVE PROCESS SEQUENCE

SUMMARY

i l

.g .

TU8E PREPARATION e

SLEEVE INSERTION 8

a LOWER JOINT FORMATION UPPER JOINT FORMATION INSPECTION (Process Verification) 1681cl0216c/011785:5 56 4-2 W

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)

, . WESTINGHOUSE PROPRIETARY Ct. ASS 3 0

'4.1.2 TU8E HONING ..

. 1 The sleeving process includes honing the ID ' area of tubes to be sleeved to prepare the tube surface for the hybrid expansion joint and the lower joint by removing loose oxide and foreign material. Honing also reduces the radioactive shine from the tube bundle, thus contributing to reducing man-rem exposure.

' Tube honing may be accomplished ~by either [ ].a.c.e Both processes have been shown to provide tube inside diameter surf aces compatible withmechanjcaljointinstallation. The selection of the honing process used

~

is dependent primarily on the installation technique utilized, the scale of the sleeving operation (small scale vs. large scale sleeving), and the

, customers site specific technical requirements. Evaluation has demonstrated-that neither of these processes remove any significant fraction of the tube wall base material.

4.1.2.1 [ Ja,c.e HONING

. Tube honing will be performed using a [

4 ja,c.e A limit switch is included in the system design that will prevent the insertion drive from reversing direction until the desired length of the tube has been honed.

A waste handling system may be used to collect the [ ],ac,e the hone debris, and the oxide removed from the tube ID. [

Ja,c.e There may also be an inlet to the 1751c/0223c/020685:5 63 4-3

-, ,- -r - - --n,-, - - , - , - . we ---,--------,-,--,--w+-, -

, ---ryg,,n-,-wem-- , - - - - - - - --,--s -y ,-~ -we

,s WESTINGHOUSE PROPRIETARY C1. ASS 3 3a.c.e 4.1.2.2 ORY HONING

~The dry hone process is similar to ( -

-r ] The dry hone process is typically more

applicable to hands-on (manual) or small scale sleeving operations.

In order to remove sloose oxide debris produced by the dry honing operation,

~

, the tube interior is swabbed utilizing a fluid (typically detonized water or isopropyl alcohol) soaked felt pad to an elevation slightly less than the honed length, but above the top of the installed sleeve.

4.1.3 ' FIBER OPTIC INSPECTION (CONTINGENCY)

As a contingency option to spot check that tube ID surfaces have been honed, a fiberscope inspection any be perforged on some of the tubes to be sleeved.

Tubes to be fiberscope inspected would be selected randeely throughout the

~

actual honirig process. - This fiberscope inspection would be accomplished prior to sleeve insertion.

4.2 St.EEVE, INSERTION AND EXPANSION The process of sleeving the tubes is carried out using remotely operated equipment. The following paragraphs describe the insertion of the sleeves and 4

mandrels and the hydraulic expansion of the sleeves at both the lower joint ,

and upper HEJ locations.

The sleeves are fabricated under controlled conditions, serialized, machined, cleaned, and inspected. They are typically placed in plastic bags, and 4 packaged in protective styrofoam trays inside wood boxes. Upon receipt at the site, the boxed sleeves are moved to a low radiation, controlled region near the steam generator. Here the sealed sleeve box is opened and the sleeve removed, inspected and installed on the expansion mandrel. Note that the 1751c/0223c/020685:5 64 4-4 I

1 WESTINGHOUSE PROPRIETARY CLASS 3

-sleeve packaging specification is extremely stringent and, 1f.left unopened, ,,

the sleeve package is suitable for long term storage.

The mandrel is connected to the high pressure fluid source, e.g., Haskel

. Expansion Unit (HEU), via high pressure flexible stainless tubing. The delivery systen is manipulated to locate the guide tube attached to it near the manway. .The mandrel / sleeve assembly is then inserted into the guide tube. After the delivery system positions the sleeva upper end below the tube to be restored, [

, ]C The delivery system is manipulated to locate the guide tube near the manway for mandrel withdrawal / inspection and loading of the next sleeve / mandrel assembly. This process is repeated until all sleeves are installed and hydraulically expanded.

In the event that a sleeve becomes jauned after only partial insertion, contingency methods and tooling are used to remove the Jamed sleeve. The tube will then be dispositioned by way of a non-conformance report after considering the appropriate input.

I 1

- 1751c/0223c/020185:5 65 4-5 l l

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= \-

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, WESTIlHiHOUSE PROPRIETARY CLASS 3 4.3 LOWER JOINT SEAL ,,

At the primary face of the tubesheet, ,the sleeve is joined to the tube by a .

m;

[

t 4.

( '-

34c.e The contact fo'rces, between the sleeve and tube due to the initial hydraulic expansion are sufficient'to keep the sleeve from rotating during the [ ~

' ~

],ac.e s

The appropriata extent of hard gall expansion of the sleeve is attained by

[' ,

]C The hard roller torque is calibrates on a standard torque calibrator prior to initial hard -

rolling operatidas and subsequently recalibrated at'the beginning of each shift for automatic tooling. This control and calibration process is a proven -

technique used throughout industry in the installation of tubes in heat exchangers.

[

s l ]a,c,e This process is repeated until all installed sleeve lower ends are rolled.

~

1751c/0223c/020185:5 66 N-4-6 s

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w- r--r--- . ._,J _ _ _ . . . _ _ _ _ _ _ , , _ , , . . . , _ , , ,,,,.r.,, _ ..y, , . _ . . . _ , _ . , _ , _ . _ , , ,_,,,..----c.-7--

1 WESTINGHOUSE PROPRIETARY CLASS 3 4.4 UPPER HYBRIO EXPANSION JOINT (HEJ) -

The HEJ first utilizes a [

~3"' In the automatic mode, [ 3 l 3 . .

~

3a,c.e _

4.5 PROCESS INSPECTION SAMPLING PLAN In order to verify the final sleeve installation, an eddy current inspection will be performed on all sleeved tubes to verify that all sleeves received the {

required hydraulic and roll expansions. The basic process check on 100 percent of the sleeved tubes will be: *

1. Verify lower ilydraulic expansion average diameter *

2. Verify lower roll and location within the lower hydraulic expansion and I average diameter 3.

[

Verify upper hydraulic expansion average diameter 4 Verify upper roll elevation and location within the upper hydraulic f expansion and average diameter.

x Tubes not satisfying the basic process check criteria will be dispositioned on an individual tube basis.

In order to monitor the sleeving process after each operation from each lot, #

eddy current data on a percentage of the sleeves will be performed to obtain  ;

sleeve ID data. As confidence is gained that the sleeving process is proceeding as anticipated, the lot sizes will be increased and percentages reduced. These average diameters will be evaluated versus the expected tolerances established through the design requirements, laboratory testing f 1751c/0223c/020685 5 67 g 4-7 jl t

I

t

. WESTINGHOUSE PROPRIETARY CLASS 3 results, and previous experience. - This evaluation will determine. whether or

- not the equipment / tooling is perfoming satisfactorily. If process data is detemined to be outside of expected ranges, further analysis will be .

perfomed.

. If required, Diatest may be used in lieu of addy current to perfom sleeve installation acceptance and in-process monitoring evaluations. Undersized

, diameters will be corrected by an additional expansion step to produce the desired degree of expansion. Oversized diameters will be dispositioned by a specific evaluation process on an -individual tube basis.

4 If it is necessary to remove a sleeved tube fran service as judged by an ~

evaluation of a specific sleeve / tube configuration, tooling and processes will be available to plug the sleeve or the lower portion of the sleeve will be removed and the tube will be plugged.

As mentioned previously, the. basic process dimensional verification will be completed and evaluated for 100 percent of all installed sleeves.

1751c/0223c/020185:5 68 4-8

r 1 1

WESTINGHOUSE PROPRIETARY CLASS 3 4.6 ESTABLISHMENT OF SLEEVE JOINT MAIN FABRICATION PARAMETERS-4.6.1 LOWER JOINT The main parameter for fabrication of acceptable lower joints is sleeve [

].a,c.e 3),,,,{ 3a,c.e is determined by [

].ac,e Accordingly, rolling torque was varied to achieve the desired sleeve [ Ja,c.e in the original Model 44 1

program (also applicable to the mo' del 51). [

]C was achieved was used throughout the program verificatio,n testing.

4.6.2 UPPER HEJ The main parameter for fabrication of HEJ's (in-sludge and out-of-sludge) which met the leak rate acceptance criteria was [

1 .

4-4

]a,c,e (Refer to Section 3.3.5.3 for an additional discussion of the roll expansion torque for the in-sludge case.)

In the first sleeving project perfor,ned by Westinghouse, hydraulic expansion axial length was also evaluated. [

].a,c.e Therefore, in later programs, the HEJ hydraulic expansion axial length [

1751c/0223c/020185:5 69 49

. WESTINGHOUSE PROPRIETARY CLASS 3 ga,b,c.e r '

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i i

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l l 1751c/0223c/020185:5 70 4-10

z 1 WESTINGHOUSE PROPRIETARY CLASS 3 5.0. SLEEVE / TOOLING POSITIONING TECHNIQUE ,

i 1

' 5.1 REMOTELY OPERATED SERVICE ~ ARM (ROSA)

ROSA is a general purpose six axes all-electric conputer-controlled robot used for nuclear service work. Its function. is to serve as a remotely controlled tool positioner and thereby reduce worker radiation exposure. The major RCSA

system components include the mechanical ar,m with a servo controller and the supervisory conputer control console contained within a trailer located

- outside containment. The operator issues commands 'to the supervisory computer through the, control console and keyboard. The supervisory computer interprets these commands and calculates the desired angular positions for each axis of -

the mechanical arm. These desired angular positions are then sent to the servo controller. The servo controller drives each axis to its desired position, and sends status information back to the supervisory conputer. This cycle is continuously executed at a high rate of speed, providing smooth and controlled motions ,

i One application of ROSA is its use as a "No Entry" tool positioner for primary

, side steam generator operations. The term "No Entry" signifies that ROSA installation / removal, tool changing, and tool operations are performed without any personnel passing through the plane of the manway's outer surface.

ROSA is loaded _into the channel head by use of a ramp loading fixture wounted to the manway flange. The tool end of ROSA is clasped to this fixture.-

Through a combination of ROSA movements and linear movements of the loading fixture, ROSA is loaded into the channel head such that its base end and four hydraulic camlocks end up approximately 2 inches below the tubesheet. From there, a joystick controller in the control trailer is used to drive the camlocks up and into the tubes. These camlocks are then pressurized to 750 psi, generating.the necessary frictional holding force to secure ROSA to the tubesheet. The tool end of ROSA is then unclamped from the loading fixture.

With the base end of ROSA secured to the tubesheet, ROSA is progranmed to reach out through the manway such that tools can be manually installed or 1751c/0223c/020185:5 71 5-1 D

,,, , ~, ,w w-, -,-,w-y w---w -g.-v~-, w,

. WESTINGHOUSE PROPRIETARY CLASS 3 removed. ROSA is then,prograused to pull the tool in through the..eanway and up to the tubesheet. '

The ROSA computer is. Initialized with the mounting location of the base (row and coluen) and with the tool being used. The operator can then enter row and .

column commands through a keyboard and ROSA will automatically position the tool underneath the desired tube. The tubesheet:is divided into regions which

, are used by the computer to generate a tool path from the present location of the tool to its destination tube. Although the computer maintains the tool's row and column position its actual row and column position is still verified every hour. .

Tools'which are positioned by ROSA include:

1) Eddy Current Tool

2) Mechanical Plugging Tool

3) 'ower Hardrolling Togi

4) Sleeving Adapter Tool - used for honing, swabbing, fiberscoping, sleeve insertion, expansion, and ultrasonic -

testing a

All these tools are controlled from inside containment, independently from ROSA. ROSA is progreened to move the sleeving adapter tool to a location over the menway so that there is an assembly window above the aanway to change out the various* tools which it can position.

The tools typically have low light level cameras or fiberscopes mounted on them. These caneras or fiberscopes are used to help verify exact positioning of the tool under the desired tube, to verify that sleeves, hardrollers, UT probes, etc., are fully inserted (contacting the tube end) before initiating their. operations and to assist in determining the tooling performance. The three axis joystick controller can be used to make minor position and orientation adjustments of the tool so that it is correctly aligned with the

• tube.

1751c/0223c/020185:5 72 5-2 l

l

l 1

WESTINGHOUSE PROPRIETARY CLASS 3 5.2 ALTERNATE POSITIONING TECHNIQUES Under some conditions, positioning of sleeve / tooling with the base ROSA system may not be practical. In these circumstances, an alternate positioning technique may be utilized. These alternate techniques may include alternate robotic or semi-remotely-operated equipment, hands-on (manual) positioning and installation, or the combination of two or more tooling subsystems into one larger tooling system.

3 -

Note ti.it with all positioning techniques, the processes actually used to install the, sic ves (hydraulic expansion, mechanical rolling, etc.) will not be changed due to t he use of an alternate sleeve / tooling positioning -

technique. It is the processes which the sleeves are subjected to that are critical to their successful installation; the technique used to position the sleeves and tooling is not critical so long as it does not affect tne sleeve installation processes.

4 i

~

1751c/0223c/020185:5 73 5-3

1

, WESTINGHOUSE PROPRIETARY CLASS 3 6.0 NOE INSPECTABILITY .

The Non Destructive Examination (NDE) development effort has- concentrated on two aspects of the sleeve system. First, a method of confirming that the u

. joints meet critical process dimensions is required. Secondly, it must be shown that the tube / sleeve assembly is capable of being evaluated through subsequent routine in-service inspection. In both of these efforts, the inspection process has relied upon eddy current technology.

, 3 . '

6.1 EDDY CURRENT INSPECTIONS The eddy cu ent inspection equipment, techniques, and results presented -

herein apply to the proposed Westinghouse sleeving process for use in steam generators which have 0.875" 00 by 0.C30" nominal wall. Due to the similarities between the Series 51 and Series 44 steen generator designs and the fact that approximately 6000 sleeves made from thermally treated Inconel 600 with mechanical joints are currently installed in Series 44 steam generators, it is expected that similar eddy current inspection results will be obtained with equipment and techniques developed for the Model 51 steam

. generators.

4 Eddy current inspections are routinely carried out on the steam generators in accordance with the plant's Technical Specifications. The purpose of these inspections is to detect at an early state tube degradation that may have occurred during plant operation so that corrective action can be taken to minimize further degradation and reduce the potential for significant primary-to-secondary leakage.

The standard inspection procedure involves the use of a bobbin eddy current probe, with two circumferentially wound coils which are displaced axially along the probe body. The coils are connected in the so-called differential mode; that-is, the system responds only when there is a difference in the properties of the material surrounding the two coils. The coils are excited by using an eddy current instrunent that displays changes in the material surrounding the coils by measuring the electrical impedance of the coils. In the past, eddy current instruments normally excited the coils at a single 1751c/0223cIO20185:5 74 6-1

1 1

t

, WESTINGHOUSE PROPRIETARY Ct. ASS 3 l

l frequency. However, Westinghouse and the industry are now using , -

i multi-frequency instrumentation for the inspection of steam generator tubi ~ng.

This involves simultaneous excitation of the coils with several different test -

frequencies.

The outputs of the various frequencies are combined and recorded. The contined data' yield an output in which signals resulting from conditions that do not affect the integrity of the tube are reduc p. By reducing unwanted signals, improved inspectability of the tubing results (i.e., a higher

~

Signal-to-noise ratio). Regions in the steam generator such as the tube supports, the tube, sheet, and sleeve transition zones are examples of areas where sultifrequency processing has proven valuable in providing improved -

inspectability.

A number of addy current probes and signal processing systems are available for the eddy current inspection of the tube / sleeve assembly. In addition to

-the conventional bobbin coil, probe, there are a rotating pancake coil and a cross-wound coil probe. Any of these probes may be used with either single frequency or multifrequency instrumentation. -

1 After sleeve installation, all sleeved tubes are subjected to a series of, eddy -

current inspections. Some of these inspections are part of a process control procedure to verify correct sleeve installation. However, each tube / sleeve assembly also receives an addy current inspection for baseline purposes to which all subsequent inspections will be compared.

Verification of proper sleeve installation is of critical importance in the sleeving process. An "in-process" eddy current inspection is conducted utilizing one frequency in the absolute mode with a conventional bobbin coil

[

probe. This inspection is performed during sleeving installation to provide "in-process" verification of the existence of proper hydraulic expansion and hard roll configurations and also to allow determination of the sleeve process dimensions both axially and radially, using the strip chart recording.

The inspection for degradation of the tube / sleeve assembly has typically been performed using conventional bobbin coil probes operated with multifrequency I

1751c/0223c/020185:5 75 l

6-2 l

l

l-

-WESTINGHOUSE PROPRIETARY CLASS 3

. excitation. For the straight length regions of the tube / sleeve assembly, the inspection of the sleeve and tube is consistant with normal tubing l inspections. In tube / sleeve assembly joint regions, data evaluation becomes more complex. The results discussed below suggest the limits on the volume of

.. degradation that can be detected in the vicinity of geometry changes. For the parent tube, these limits are on the order of two to three times the response of the ASME calibration standard using the conventional bobbin coil probe.

9

' The detection and quantification o'f degradation at the transition regions of the sleeve / tube assembly depends urn .the signal-to-noise ratio between the i degradation, response and the transition response. As a general rule, lower frequencies tend to suppress the transitior signal relative to the degradation -

l l

signal at the expense of the ability to quantify. 'Similarly, the inspection 1 of the tube through the sleeve requires the use of low frequencies to achieve detection with an associated loss in quantificaton. Thus, the search for an optimun eddy current inspection represents a trade-off between detection and l quantification. With the conventional bobbin type inspection, this optimization leads to a primary inspection frequency for the sleeve on the I orderof[ ]a,ce and for the tube and transition regions on the order  !

,of[ 3a,c.e Figure 6.1-1 shows the response of the ASME tube calibration standard using a conventional bobbin coil. Figure 6.1,-2 shows the response of a typical expansion transition at the same frequencies as Figure 6.1-1 but at a factor of two lower sensitivity for the non-mixed channels. In Figures 6.1-1 and 6.1-2, the results of combining the 50 kHz and 150 kHz responses to eliminate the transition signals are depicted. Note that in the transition regions a signal with twice the amplitude of the standard would be detectable. However, with present instrumentation the actual noise level from the electronics limits the usefulness of this approach.

For those regions of the sleeve where the assembly has no transitions, a conventional bobbin coil inspection provides detection and quantification capability. Figure 6.1-3 shows a typical [ ]a,ce base angle versus degradation depth curve for the sleeve from which 00 sleeve penetrations can -

be assessed.

l

. 1 1751c/0223c/020185:5 76 6-3 L

t

s WESTINGHOUSE Pit 0PRIETARY CLASS 3 in the regions of the parent tube above the sleeve, conventional bobbin ~ coil inspections will continue to be used. However, since the diameter of the sleeve is smaller than that of the tube, the fill factor of a probe inserted ,

through the sleeve may result in a decreased detection capability for tubing degradation. Thus, it may be necessary to inspect the unsleeved portion of .

the tube above the sleeve by inserting a standard size probe through the U-bend from the unsleeved leg of the tube.

While there are a number of probe configurations that lend themselves to I

improving the_ inspection of the tube / sleeve assembly in the regions of configuration tran91tions, the cross-wound coil probe has been selected as offering a significant improvement over the conventional bobbin coil probe, -

yet retaining the simplicity of the inspection procedure.

The overall inspection procedure involves the use of the cross-wound probe which significantly reduces the responses of the transitions, coupled with a multifrequency mixing technique for further reduction of the remaining noise signals. This system reduces the interference from all discontinuities which

- have 360-degree synnetry, providing improved visibility for discrete .

discontinuities. As is shown in the accompanying figures, in the laboratory this technique can-detect 00 tube wall penetrations with acceptable ,

signal-to-noise ratios at the transitions when the volume of metal removed is equivalent to the ASME calibration standard.

The signif tcant reduction of response from the tube / sleeve assembly transitions due to the use of the cross-wound coil is shown by a comparison of Figures 6.1-4, 6.1-5, and 6.1-6 for the sleeve standards, tube standards and transitions, respectively. Again, this is further improved by the combination of the various frequencies. For the cross-wound probe, two frequency combinationsareshown;[

la,b,c.e Figure 6.1-7 shows the phase / depth curve for the tube using

-this combination. As examples of the detection capability at the transitions, Figures 6.1-8 and 6.1-9 show the responses of a 20 percent 00 penetration in the sleeve and 40 percent 00 penetration in the tube, respectively.

1751c/0223c/020185:5 77 6-4 1

1 2

e 1 .

• e s

Figure 6.1-1 ~

E.C. Signals from the ASTM Standare, Machined on the Twee 0.0. of the Sleeve Tube Assembly Without Exoansion (Conventional Differential Coil Proce) 6-5

1 7

1 2

I a

I l

l i

e a

Figure 6.1-2 E.C. 3;gnals from the Excension Transition Region of the Sleeve-Tube Assemely (Conventional Differential Coil Proce!

6-6 e

1 3

) . .

0 Figure 6.1-3 i

Eddy Current Calibration Curve for ASME Sleeve Stancard at (700JW21a,c.e with the Conventional Ditterential Coil Proce I

6-7

. s.

3

+

y-e Figure 6.1-4 E.C. S'ensis from the ASTM Standard. Machined on the Sleeve

! C.0. of the Sleeve Tune Anemely without Essension (Cron l Wound Coil Protel 1

6-8

i I

1 l 3

1 i

) . .

4 Figure 6.1-5 E.C. Signals from the ASTM Standare. Machined on toe Twee 0.0. of the Steeve-Tube Auemely Without Excansion (Cross Wound Coil Proce) 6-9

3 t

• 4 e

a Figure 6.1-6 E.C. Signals from. the Excension Transition Region of the Tube $leeve Assemoly (Cross Wound Coil Procol 6-10 l

j

1 3

e 1 . '

e

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8 Figure 6.1-7 (W a,c.e Eddy Current Calibration Curve for ASME Tube Stancar and a Mix Using the Cross Wound Coil Pecce 6 11

c I

3

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I Figure 6.1-8 -

E.C. Signal from a 20% Does Hole. tHalf he Volume of ASTM Standard, Machined on the Sleeve O.D. in the taoenson Transiten Region of the Sleeve.Tuoe Assemoly (Crom Woune Coil Procol 6-12 9

p-

}~

_ . J .

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4 Figure 6.1-9 E.C. Signal from a 40% ASTM Standard, Machined on the Tuce 0.D. in the Espansion Transition Moon of Steeve Tube Asemoly (Crom Wound Cod Probe) 6-13

4

. 3

v. '

l Figure 6.1-10

• Eddy Current Resoonse of Sousee and Taoered sleeve Enos Comoared to the Escansion Transitions for the Conventional Settin Coil Prete 6-14 e

,,,_,_,,,w,,-,---

.j-3

+

e

.. g . .

e d

Eddy Current Response of the ASME Tube Standard of the Sleeve Multifrequency Using the Combination Cross Wound Coil Prone and Figure 6.1-11 6-15

.j- .

. - . . _ , , , _ . . _ _. . . _ _ . . . - 1 ._ _.____._.- _ _._. _ . . , . , _ . . _ _ _ . _ . _ - - _ _ . _ _ _ . _ . . - _ . , . , _ .

WESTINGHOUSE PROPRIETARY Ct. ASS 3  !

l 1~ l The preceding discussion has centered around the inspection of the expansion transition regions of the assembly. For inspection of the region at the top ,

4 end of the sleeve, the transition response using the conventional bobbin inspection is still larger than that of the expansion regions as shown in Figure 6.1-10. Thus, the signal-to-noise rati.os for this part of the tube / sleeve assembly is about a factor of four less sensitive than that of the expansions. Some improvement has been gained by tapering the well thickness at the top and of the sleeve. This reduces the end-of-sleeve signal by a factor of approximately two. The crosswound coil, however, again significantly reduces the response of the sleeve end. Figure 6.1-11 shows the response of various A5fE tube. calibration standards placed at the end of the -

4 sleeve using the cross-wound coil and the [ ]C frequency combination. Note that under these conditions, degradation at the top and of

the sleeve / tube assembly can be detected.

6.2 Sum 4RY Conventional eddy current techniques have been modified to incorporate the ,

most recent technology in the inspection of the sleeve / tube assembly. The resultant inspection of the sleeve / tube assembly involves the use of both, a -

conventional bobbin coil for the straight regions of the sleeve / tube assembly and a cross-wound coil for the transition regions. It should be emphasized that the transition regions of the assembly, where the cross-wound coil and multifrequency processing are necessary for degradation detection, comprise only a small percentage of the overall sleeve / tube assembly. Thus the conventional inspection would constitute the bulk of the eddy current inspection. While there is a significant improvenent in the inspection of portions of the assembly using the cross-wund coil, efforts continue to advance the state-of-the-art in eddy current inspection techniques. As l improved techniques are developed and verified, they will be utilized. For l the present, the cross-wound coil probe represents an inspection technique that provides additional sensitivity and support for eddy current techniques as a viable means of assessing the tube / sleeve assembly.

l' 1751c/0223c/020185:5 78 6-16

1 WESTINGHOUSE PROPRIETARY CLASS 3 7.0 ALARA CONSIDERATIONS FOR SLEEVING OPERATIONS-

, The repair of steam generators in operating nuclear plants requires the  !

utilization of appropriate dose reduction techniques to keep radiation exposures As Low As Reasonably Achievable (ALARA). Westinghouse maintains an extensive ALARA progr a to minimize radiation exposure to personnel. This

. program includes: design and improvemen't of remote and semi-remote tooling,

' including state-of-the-art robotics; decontamination of steam generators; the 3

use of shielding to minimize radiation expo'sure; extensive personnel training utilizing mock-ups; time trials; and strict qualification procedures. In addition, computer programs (REMS) exist which can accurately track radiation exposureachanulation. ,

The ALARA aspect of the tool design program is to develop specialized remote tooling to reduce the exposure that sleeving personnel receive from high radiation fields. . A design objective of the remote delivery sleeving system is to eliminate channel head entries and to complete the sleeving project with total exposures kept to. a minimum,1. e., ALARA. The manipulator arm is installed on a fixture attached to the steen generator manway after video cameras and temporary nozzle cov' e rs have been. Installed. The control station

' operator (C50) then manually operate controls to guide the manipulator arm through the manway and attach the baseplate to the tubesheet. The installation of the arm requires only one platform operator to provide visual observation and assistance with cable handling from the platform. The control stat, ion for the renote delivery systen is located outside containment in a specially designed control station trailer.

The control of personnel exposures can also be effected by careful planning, training, and preparation of maintenance procedures for the job. This form of administrative control can ensure that the minimum number of personnel will be used to perform the various tasks. Additional methods of minimizing exposure include the use of remote TV and radio surveillance of all platfom and channel head operations and the monitoring of personnel exposure to identify ,

high exposure areas for timely improvement. Local shielding will be used whenever possible to reduce the general area background radiation levels at the work stations inside containment. A combination of these techniques is expected to be used in this steam generator sleeving project.

1751cl0223c/020185:5 79 7-1

. IdESTINGHOUSE PROP'LIETARY CLASS 3 7.1 ROSA SLEEV!NG OPERATIONS ..

The Remotely Operated Service Arm (ROSA) is a remotely-operated robotic, general purpose tool positioning systa designed for performing various maintenance tasks in the steam generator channel head and other radiologically -

hostile environments. The system is operated remotely from the control station located outside containment up to 200 feet from the channel head. The

, arm is designed to accept a family of and effectons that are used to implement the various processes used in steam generator tube maintenance.

7.2 MANIPULATOR ENO EFFECTOR $

The ROSA system is designed to assist'in perfoming a wide variety of tasks in the channel head. This is accomplished by firstly attaching the appropriate end effector to the am. The end effectors are designed for specific or multi-purpose use during sleeving operation. Some current applications of remote manipulators are steam generator eddy current inspection, plug weld repair, tube end repair, mechanical plug installation, and tube sleeving operations. An end effector is equipped with a standardized quick disconnect

• V-band coupling for manual attachment to the manipulator from the steam generator platform. The am is extended through the manway and the quick' disconnect coupling is oriented at right angles to the axis of the manway.

This allows the changing of and effectors outside direct shine of the manway radiation, minimizing radiation exposure.

7.2.1 SLEEVE / TOOLING ENO EFFECTORS The sequence of process steps and associated tooling required to complete a steen generator tube sleeving prnject results in many end effector changes.

The sleeving operations of tube end rolling (contingency), tube honing, fiberscoping (contingency), sleeve / mandrel insertion and expansion, upper hardroll, lower hard roll, process verification eddy current inspection, and baseline eddy current inspection will require a significant number of tool changes during the project. The platform operator will be required to change -

end effectors of increasing complexity from fiberscope and lower hard roller tooling to the more complex sleeve / mandrel insertion and expansion tooling 1751c/0223c/020685:5 80 7-2

1 WESTINGHOUSE PROPRIETARY CLASS 3 system. The number 'and frequency of changes will depend on the s' cope of the sleeving project.

7.2.2 IN-PROCESS OPERATIONS The necessity of having a platform operator available near the platform extends into the in-process sleeving operations. The useful life of a hone is expected to be limited to approximately 5-5,0 tubes (depending on the honing process utilized) before the hone will need to be replaced. The fiberscope inspection sequence may require various lengths of fiberscopes to reach all of the tubes during the inspection. The sleeve / mandrel insertion and expansions operations are expected to require the major part of the in-process time spent

• on the platform. The renoval of spent expansion mandrels and the installation of the new sleeve / mandrel unit may have to be done manually from the platform. The hard rolling and eddy current operations will require much less time on the platform.

7.3 CONTROLSTATIONkNCONTAINMENT

,The process control stations for the various sleeving processes will be located in containment in a low radiation area near the steen generator platforms. These wrk stations are required to operate and control the i individual sleeving processes and are independent of the ROSA systems controls located outside containment. The variation in service requirements such as air,' water, electricity, radwaste generation, and proximity of controls-to-processes makes the in-containment control stations a necessity.

! 7.4 POTENTIALS FOR WORKER EXPOSURE l

l The continued development of the ROSA sleeving process is expected to j significantly reduce the radiation exposure to workers in comparison to l previous sleeving projects. The elimination of channel head entries for the installation and renoval of sleeves and sleeve tooling fixtures will keep

• personnel out of the high radiation fleIds of the steam generator channel heads. The majority of the sleeving operations will be done from the control stations with one or two workers stationed on or near the platform. However.

1751cl0223cl020185:5 81 7-3

(

WESTINGHOUSE PROPRIETARY CLASS 3 -

1 in the preparation of the steam generators'for sleeving operations,+ entries l

into the channel heads may be required.

l l

7.4.1' N0ZZLE COVER AND CAMRA INSTALLATION / REMOVAL The installation of temporary nozzle covers in the reactor coolant pipe nozzles in preparation of the steen generators for sleeving operations will require channel head entries. The covers are ins,talled to prevent tne accidental dropping of any foreign objects (i.e., tools, nuts, bolts, debris. .

etc.) into the reactor coolant loops during sleeving operations. In the event thatanaccidentjidoccur,inspectionsoftheloopswouldberequiredandany foreign objects or debris found would have to be retrieved. The impact on

• schedule and radiation exposures associated with these recovery operations would far exceed the time and exposures (less than 1 minute) expended to install or remove loop nozzle covers. Consequently, It .is considered an ALARA-efficient procedure to utilize temporary nozzle covers during sleeving operations. .

The use of video monitoring systems to observe ROSA operations in the channel .

head will also require manual installation. The installation of overview cameras to enitor sleeving operations will require a full or partial channel head entry to be installed.

The installation and removal of this equipment in the steam generators are the only scheduled requirenents for channel head entry during the sleeving project.

7.4.2 PLATFORM SETUP /SUPERV!5!0N The majority of the radiation exposures recorded for the sleeving program is espected to result primarily fron personnel erking on or near the stems generator platforms. The setup and checkout of equipment for the various sleeving processes, the installation /renoval of ROSA, the changing of end effectors, and the operation of the sleeve / mandrel insertion and expansion system are the major sources of radiation exoosure. In addition to channel head video monitoring systems, visual monitoring and supervision by one or more workers on the platform will be required for a major part of the sleeving 1751c/022,1c/020185:5 82 7-4

. - - , _ _ - - - - - - , . - . _ _ - - . , . , . , _ . , - , - . . - _ - - , , . , - , . . , .--n.-_..,.,_,n-

.y ,

, WESTINGHOUSE PROPRIETARY CLASS 3 schedule. Experience has shown that rapid response to equ,ipment' adjustment requirements is efficiently accomplished by having a platform worker standing

, 3 by in a relatively low radiation area during operations. Worker standby j, [ stations have ranged from the low radiation fields behind the biological shield to lead blanket shielding installed on the platform. Even though radiation levels on the platform are wch lower than channel head levels, a substantially larger enount of time will be spent on the platforms giving rise to personnel exposures. An evaluation of radiation surveys around the steam generators should indicate,appropr'iate standby stations.

7.5 RA0 WASTE GENERATION

~

The surface prep 6rition of tubes for the installation of sleeves requires that

', the oxide film be renoved by a honing process. A flexihone attached to a flexible rotating cable will be used to reevs the oxide film on the inside w

surface bf the steam generator tubes. The volume of- solid radwaste is

( k. expected 50consistofspenthones,flexiblehoningcables,honefilter assemblies -(optional), [ ]"'C and the

-normal anti-C consumables associated with steam generator maintenance. The

s. .f

, , anti-C'codsunables are usually the customer's responsibility and will not be Y., . '.

i addresstdsin this report. -

a w h ,' N 7_

%. Forthe[ ]a,c.e ,,p.oximately thirty tubes can be, honed i' bef0're the hone is changed for process control and (

• ].a.c.eIA typical estimate of the radioactive concentrationfromahonedtube,transportedbythe[ ]*'#is given in Table 7.5-1. Ther; tube hones as well as the tubes (

ly ] Consequently, radiation levels of the spent hones are normally ,10-20 mr/hr based on field measurements in previous

, sleeving projects. -

The flexible honing cable used to rotate the hone inside the tubes is also flushed during the honing process. However, the construction of the stainless *

, steel cable will cause radioactivity to build up over the course of the Nproject. hadiation levels on segments of the cable could reach 5-10 R/Hr contact dosa rates for major sleeving jobs, it is expected that an average of

• l l

, 1751c/0223cl020185:5 83 7-5 N

~

.g

WESTINGHOUSE PROPRIETARY Ct. ASS 3.

TA8t.E 7.5-1 ..

ESTIMATE'0F RAOI0 ACTIVE CONCENTRATION IN WATER PER TU8E HONED (TYPICAL) a,c.e Percent Inventory Activity

!sotope Concentration (uci) (uci/cc of H20) e

. f i .

t i

L ..

ASSUMPTIONS ,

1) Tube honed 48 inches (in length)

2) Water flow rate of 0.6 gallons per tube honed

' 3) Essentially all radioactivity removed from tubes honed.

1751c/0223c/020185:5 84 7-6

1

, WESTINGHOUSE PROPRIETARY CLASS 3

~

one cable per steau generator will be used during the sleeving project. The cables are consumables and are druened as solid radwaste.

l 7.6 AIRBORNE RELEASES l

The implementation of the proposed sletving processes in operating nuclear plants has indicated that the potential for airborne releases is minimal. The majoroperationsinclude[ ]a.c.e and sleeve installation.

Experience has shown that these sleeving processes do not contribute to

, airborne releases. .

7.7 PERSONNEL EXPOSURE ESTIMATE -

The total personnel exposures for steam generator sleeving operations will depend on several plant dependant and process related factors. These may include, but not be limited to; the scope of work (quantity c/ sleeves, etc),

plant radiation levels, ingress / egress to the work stations, equipment perfomance and overall cognizance of ALARA princ191es. Consequently, the projection of personnel exposures for each specifi; plant must be performed at the completion of mockup training when process times for each operation have been recorded. The availability of plant radiation levels and worker process times in the various radiation fields will provide the necessary data to project personnel exposure for the sleeving project.

The calculation of the total MAN-REM exposure for completing a sleeving project may typically be expressed as follows:

P=N .O g +Sg.Ng P = Project total exposure (MAN-REM)

N3 = Number of sleeves installed

. D3 - Exposure / sleeve installed 1751c/0223c/020185:5 85 7-7

-f -,n -

g ,-,,+,n-,,y.,--~,----,-e-

WESTINGHOUSE PROPRIETARY CLASS 3 59 Equipment setup / removal exposure per steam generator

.Ng = Number of steam generators to be sleeved ,.

This equation and appropriate variations are used in estimating the total personnel exposures for the sleeving project. ,

a e

1751c/0223cl020185:5 86 7-8

1 WESTINGHOUSE PROPRIETARY CLASS $

8.0 INSERVICE INSPECTION plan FOR SLEEVED TUBES.

In addressing current NRC requirements, the need exists to perform periodic inspections of the supplemented pressure boundary.- This new pressure boundary

, consists of the sleeve with a joint at the primary face of the tubesheet and a joint at the opposite end of the sleeve. ,

The inservice inspection program will consist of the following. Each sleeved I tube will be eddy current inspected on completion of installation to obtain a baseline signature to which all subsequent inspections will be compared.

Periodic inspections to monitor sleeve wall conditions will be performed in

. accordance with the inspection section of the plant Technical Specifications. .

This inspection will be performed with multi-frequency eddy current equipment.

t As part of.the inspection of the sleeved tubes, there will be a series of pressure / leakage tests. These tests are intended to test the integrity of the mechanical joint against leakage at both primary and secondary pressure loadings. The tests will be conducted at the conclusion of the. sleeving

.. operation and will be performed by the owner in accordance with applicable requirenents of the ASME Code and plant procedures. Periodic pressure testing of the sleeved tubes will also be performed in accordance with the, plant

3. ,

Technical Specifications.

[

i

, 1751c/0223c/020185:5 87 8-1 4

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WESTINGHOUSE PROPRIETARY CLASS 3 l

WCAP 10820 SG-85-03-056 NORTHERN STATES POWER COMPANY

' PRAIRIE ISLAND NUCLEAR GENERATING PLANT l LICENSE AMENDMENT REQUEST DATED MAY 17, 1985 EXHIBIT D .

3 PRAIRIE ISLAND UNITS 1 AND 2

, STEAM GENERATOR SLEEVING REPORT (Brazed Sleeves) .

l I

I March 1985 l

1

' j I

i PREPARED FOR NORTHEiJ4 STATES POWER COMPANY l

l l

WESTINGHOUSE ELECTRIC CORPORATION STEAM GENERATOR TECHNOLOGY DIVISION

• P.O. BOX 855 ^

PITTSBURGH, PA 15230 l

l l

1 1

PROPRIETARY INFORMATION NOTICE TRANSMITTED HEREWITH ARE PROPRIETARY AND/OR NON-PROPRIETARY VERSIONS OF  !

DOCIMENTS FURNISHED TO THE NRC IN CONNECTION WITH REQUI3T3 FOR GGERIC AND/OR l

PLANT SPECIFIC REVIEW AND APPRWAL. i i . .

' IN ORDER TO'. CONFORM TO THE REQUIREMENTS OF 10CFR2.790 0F THE COMMISSION )

REDULATIONS C3CERN2NG THE PROTECTION OF PROPRIETARY INFORMATION 30 SUBMITTED .

TO THE NRC, THE INFORMATION WHICH IS PROPRIETARY IN THE PROPRIETARY VERSIONS IS CONTAINED WITHIN BRACKETS AND WHERE THE PROPRIETARY INFORMATION HAS BEEN DELETED IN THE NCN-PROPRIETARY VERSIONS QE.Y THE BRACKETS REMAIN, THE

.INFORMATION THAT WAS CONTAINED WITHIN THE BRACKETS IN THE PROPRIETARY VERSIONS HAVING BEEN DE.ETED. THE JUSTIFICATION FOR Q. AIMING THE INFORMATION SO DESDNATED AS PROPRIETARY IS INDICA'TE IN BOTH VERSIONS BY MEANS OF LOWER CASE

)

LEITERS (a) THROUGH (g) CONTAINED WITHIN PARENTHE3ES LOCATED AS A SUPERSCRIFT IMMEDIATELY FO!l.CWING THE BRACKETS ENC.0 SING EACH ITEM OF INFORMATION BEING  !

l IDENTIFIED AS PROPRIETARY OR IN THE MARGIN OPPCSITE SUCH INFORMATION. THESE LNH CASE LITTERS REFER TO THE TIPES OF INFORMATION WESTINGHOUSE CU HCLDS IN CONFIDENCE IDENTIFIED IN SECTIONS (4)(ii)(a) through (4)(ii)(g) 0F THE AFFIDAVIT ACCOMPANYLNG THIS TRANSMITTAL PURSUANT TO 10CFR2.790(b)(1).

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.Se' fare me, the undersigned authcMty, personally acceared Ackert A. Wiesamann, who, being by me duly sinom aco:rting to law, deposes and says that he is authori:ed to executa tais Affidavit en -

behalf of Wertinghcuse ElecMe,Cc5hcration ("'4estinghcuse") and : hat l the ave.'=aants of fac set forth in this Affidavit are true and cor sc: l to the best. of his knowledge, infomation, and belief:

& E.GUtdN %

Rccert A. Wtesamann, Manager Regulatory and Legislative Af' airs 9

$ worn to and subscribed before me this [, day b [ d - 1980.

of m ,

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e Y' lf-!A 6' Notary Y$Cl;i,'C l

. . . . .x -

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(i) I am Managar cf Requia::ry and Lsgisladve Af* airs f.n ce .'luclea.r .

, Tec::ncicqy Oivision cf Westinghcusa Elec:Mc Cer;craden, and as suen, I have teen s;ecifically delega:ad en funcden cf.-rtviewing.

the ,.reprietary infer =aden scught = he witheid frc::: ;uhlic dis- -

closure in c=nnec: ten with nuclear power plant ifcansing er rule-making ,.. ,# siings, and am auceriM := ai: ply for its witanciding en behalf of ce Westinghcuse Watar Reac :r Oivisiens.

(Z) I am making Ms Af"idavit in c:nfor=anca wita i:he previsiens of 10C7R Section Z.750 of the Camission's regulations and in en,func-tien wft the Westingacuse appiteation far witholding ac==::anying this Affidavit. .

(3) I have perscnai kncwledge cf the crftaMa and precadures utili:nd ,

by Westinghcuse Nuclear Energy Systams .in designadng infcmatica as a trade secret, privilded cr as c

nfidential czzercial er .

financial infer =ation. -

(1) Pursuant u ce previsicris of paragrash (b)(4) of Sec.ica 2d90 cf taa Cemmission's reguladcas, ce fc11cwing is furnished for c:n-sideration by ca. Cc=rission in datamining whacer ce infcmaden sough't to be withheld fica public disclosure saculd be witnheld.

(,1 ) The infomatien scught t: he witheid T. punite dis- -

closure is cwned and has been he'id in c:nfidanca by Wesd ngncuse. >

(ii) The i.. "utien is of a type cust=:arily held in c:nfi- ,

danca by Wesdnghcuse and not cust:marily disclosed u the public. Westinghcuse has a radenal basis fer datamining ce types of infomatica cusmrily' held in =nfidenca by it and, in that c=nnectica, utili:ss a systam t: detar=ine when and whetMer u acid car s.in :yces of infcma:icn in

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cnfidenca. Tne ancituden cf cat systan and th.e sun.

stanca cf cat systam.c:nsttutar Wesdag=cuse ):slicy l anc ;r:vides de esdenal basis esquiM .

. I under daE systam,. f.um .cn is held. is c=nfidenca if  !

it falls -irt one cr more of savers 1 types, ce releasa cf l wMch might resuit in ce Tess of' an existng er pctandal  !

l l

1 .

c=mmetttve advantag's, as fc11ces:- l

. 1

. (a) The infcmatien reves.ls the distnguisMng aspec.s l of a precass (or c=mponent, st: ac.are, t:ci, matted, -

i et=.).where preventien af.Its use by any of Wesd ngncese's c=mpedtsrs without licanse from Westinghouse c=nsti-tutas a c=mpeddve,ecncaic advanuge over other -

c=mmanies.. ' -

+ 1

.s .

)

(h) It consisc of supporting data. including tast dau, mIative ts a. precass '(cr c=mmenent, st:=4 cure, t:ci, maced, et=.), ce applicaden of wMen dau secres

_ a a c=mpedtive eencaic advanuge, e.g., by opdminden or improved. maritetaM11ty.'

(c) Its use by a. c==cetit=r would reduca Ms ex;enditure of rescurcas or imcreve his c=catitive pcsitten f(

- 2e design, manufac=re, sMgment, insullatien, assur '

anca of quality, or~11cansing a simitar pr:cuct. .

(d) It nyaals c st er prica informaden, pndueden ccac-

• ities, budget levels, or c:=merdal serstagias of Westnghcuse, its cust::mers er sucpliers.

, (e) It reveals aspecu of past, present, ci- fu:ure Wesdngncusa er Ost:mer 'unded deveicement : Tans and s q r m of

ccancial c

rt:::ercial talue .: 'iestingncuse. l

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, (f) It c nuins ;aunuale'idans, for which ;atan: pr:-

taction ay be desirabia. .

(g) It is.not ce preper:y of .'4.es.tinghcusa, but must be tres.1::ad, as pretriatar/ by Westinghcuse ac=:rding :=

agreements with the cwner.-

3 .

• Thers art. scund ;=11cy esascas behind ca 4estinghcusa sys.am wM,ch include the following:

(a) The use of s'uch infer.::aden by '4estinghcusa gives Westinghcuse a c=m=etitive advanage over tu c:m;:stit:rs.

It is, thersfere, withheld .'. discicsurs ta prc:act the Westinghcusa c==petitive position.

It is i.ifw2ctr wMch is markeuble in many ways.

(b)

The extant to wMeh such indir.::ation is a'vailaala t:

c=mmettt:rs diminishes ce 'Jestingncuse ability :

sail pr ducts and servican involving the usa cf ==

f ailw.ustion.

j (c) (Isa by our c=mcatit:r would ;ut '4estinghcusa at a c:mmetitive disadvanuge by . :. ucing his ex:enditurt of rescur:es at cur expanse.

1 l (d) Each c=mmenent of prcprieur/ inferstien pertinent ta a'; articular c=mmesitive advanuge is ;ctantially l as valuable as ce :=ul c==cetitive advanuge. If c:mcesit:rs ac:;uire c:m:cnenu cf pr:crieury inf:rma- l tien, any cne c:= enent =ay ha =a key ts the endre .

pu==le, thersey depriving '4estingneusa of a c erd:ive advanu ge.

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(e) UnrestMc-u disclosure wculd jeccarti::a ce ;csition of prutinenca of %estnghcuse in the world' market, and cereby give a market advanuga te de pattien '

- . in tese ccuntM es..

(f) The Westinghouse capacity te invest ccrperata assau.

. in research and develcpment dacends upcn the sue: ass .

-) , in chtaining and minta'ining a. c=mpetitive advanuge.

(iii) The ,infor=aden is being transmit:ad ts the Ccmmissien in c=nfidenca and, under the previsicas of 10CFR 5ecten 2.790, ~

it. is to be received in ecnfidenca hy: the Commissien.

(iv) The infor.natien scup to be pretactad is not availatie in , l public scurtas te ce best of cur kncwledga and hel'ief.  !

+ . 1 s

(v) The wwrietary inftTT:stfen scught t= te wich' eld in this .

submittai is that whfetr is approgriataly =arked 5657 4 (20)

• Scuthern CA14fornir Mison Repair. Retcrt" (Proprieury).

_. This report has been prepared for aqd is being submittad ts 2a Staff at the. request of Ecuthorit California Eisen.

' The renc'rt deuils the design of the sleeves that are t= he -

installed in the San Oncfra Unit 1 staam genersters. The report. alsc includes the design analysis, ce ust verifica,-

tfan pecgram and descriptons of ca expanded =acnanical plug, the eclied plug and the channel head dec:numinaten precass.

~

This in.k .tien is par: of that whien will' enable Westingneuse ~

tc:

(a) Accly fer gaun prc:acticn.

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(b) 0;;1mi:a suam geners=r escair tachnicues ~= ex:and ce sortica life of staam generturs.

(c) Assist itr cust:mers ti cauin NRC appmal.

(d) Jus:tt, es des 4gir easis f=r che s:ee, generator i

i- repaire and insu11.aden maccds. -

Fureer, this informa:1cn Nas sutsuntial c...=:ercial value

. as fc11cws: - -

(a) Westnghouse plans to sell the recair techniques and

~

equipment,descrihad.in pa.. by te inf:r=ad en.

r .

(b) Westnghcuse can sail repair servicas based upon ca experienca gained' and tha insu1Taden equipment and methods deveicped.

. Punlic dise!csure of this indematica is likely ts cause siibstantiaT ham en the c==petidve pesiden of Wesdaghcuse W!*a (1) it would result in the less of valuable patan:

! righu, and (2) it would enhanca the ability of c:mcad::rs i

to design, manufacture, verify and sell suam generst:r repair eachniques for c:nnerdal power reac=rs wiecut <

cancensurata expenses.

The develcpment of ce metands and ecui; man: desc-ihed in part by ce infamaden is the result of acplying tne results '

of many years of experienca in an intansive Westingncusa ef":M and tne ex;enditure of .a c:nsicerable su= cf =eney.

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In order for c=ncatitors of Westinghcuss to ducifcata .his infer =atica, simila,r engineering ,crcgms Wuid have :c be l perder=ed and a significant mangewer ef"crt, having .::e r%"uist a talen: and experienca, wuld have to be ex; ended

~

i 1

for steam generator repair technicues. l Further the descnetit snyeth not. '

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1 O

BRAZED SLEEVE REPORT .

. TABLE OF CONTENTS

. Section Title Page 1.0 INTR 000CTION -

1-1 3 2.0' SLEEVING OBJECTIVES ANO SLEEVING,BOUNOARIES 2-1 2.1 Objectives -

2-1 4

~

2.2 Sleeving Boundaries 2-1 3.0 DESIGN 3-1 3.1 Sleeve Design Documentation 3-1 3.2 Sleeve Design Description 3-1 3.3 Design Verification: Test Programs 3-6 i-3.3.1 Design Verification Test Program Summary -

3-6 3.3.2 Corrosion and Metallurgical Evaluation Program 3-7 3.3.2.1 Corrosion and. Metallurgical Evaluation 3-22

, of Brazed Joint Region 3.3.2.2 Corrosion and Metallurgical Evaluation 3-28 of the Lower Joint 3.3.3 Test Program for the Lower Joint 3-30 3.3.3.1 Description of Lower Joint Test Specimens 3-30 3.3.3.2 Description of Veriffcation Tests for 3-30 the Lower Joint 3.3.3.3 Leak Test Acceptance Criteria 3-31 3.3.3.4 Results of Verification Tests for

• ~

- e Lower Joint 3-32 3.3.4 Test Program for the Brazed Joint 3-33 3.3.4.1 Description of Brazed Joint Specimens 3-33 3.3.4.2 Description of Verification Tests for the Braze Joint 3-33 I

3.3.4.3 Results of Verification Tests of Braze Joints 3-33 1819c/0235c/031185:5 2 i

1 TABLE OF CONTENTS (Continued) .

Section Title Page 3.3.5 Effects of Sl'eeving on Tube-to-Tubesheet Weld 3-34 h 3.J.6 Sumary of Test Results -

3-34 u

3.4 Analytical Verification . . 3-43 3.4.1 Introduction 3-43

. 3.4.2 Component Description -

3-43 3.4.3, Material Properties 3-44

~

3.4.4 Code Criteria 3-44 3.4.5 Loading Conditions Evaluated 3-44 3.4.6 Methods of Analysis 3-45 3.4.6.1 Model Development 3-45 3.4.6.2 Thermal Analysis 3-46 E 3.4.6.3 Stress Analysis 3-47 3.4.7 Results of Analyses

_{

3-49 2 3.4.7.1 Primary Stress Intensity 3-50 -

3.4.7.2 Range of Primary and Secondary 4 Stress Intensities 3-50 _

3.4.7.3 Range of Total Stress Intensities 3-51 3.4.8 References

}

3-52

~"

3.5 Special Considerations 3-64 ,

3.5.1 Flow Slot Hourglassing 3-64 3.5.1.1 Effects on Burst Strength 3-64 j 3.5.1.2 Effects on Stress Corrosion Cracking Margin 3-64 [

3.5.1.3 Effect on Fatigue Usaga 3-64  ;

3.5.2 Tube Vibration Analysis 3-65  ;

3.5.3 Sludge Height Thermal Effects 3-65  ;

3.5.4 Allowable Sleeve Degradation 3-65 3.5.5 Effect of Tubesheet/ Support Plate Interaction 3 70 j

3.5.6 Com yehensive Cyclic Testing 3-70 2 3.5.7 Evaluation of Operation with Flow Effects i Due to Sleeving 3,71 3.5.8 Alternate Sleeve Materials 3-74 1819c/0235c/031185:5 3 -1 11 J

4 3

m 1

O TABLE OF CONTENTS (Continued) .

Section Title Pm 4.0 PROCESS DESCRIPTION 4-1

'4.1 -Tube Preparation 4-1 4

-4.1.1 Tube End Rolling (Contingency.) 4.1'

, 4.1.2 Tube Honing 4.3 4.1.2.1 Wet Honing

• 4.3 4.1.2.2 Ory Honing 4-4

~

4.1.3. Fiberoptic Inspection (Contingency) 4-4 -

4.2 Sleeve Insertion and Expansion 4-4

~

4.3 Lower Joint Seal 4 4

• 4.4 Braze Joint Proi:ess 4-7 4.4.1 Brazing Material 4-7

.. 4.4.2 Flux Application '4-7 4.4.3 Brazing Operation '

4-7 4.5 Sleeve Inspection 4-8 4.5.1 Process Inspection Sampling Plan 4-8 4.5.2 Ultrasonic Inspection ~4-9 4.6 Establishment of Sleeve Joint Main Fabrication Parameters 4-10 4.6.1 Lower Joint , 4-10 4.6.2 Upper Joint '

4-10

'5.0 SLEEVE / TOOLING FOSITIONING TECHNIQUE 5-1

~

- 5.1 Remotely Operated Service Arm (R'0SA) 5-1 5.2 Alternate Positioning Techniques 5-3 1819c/0235c/031185:5 4 g44

~ ~ ~ ' ' * ~

J-1-

TA8LE OF CONTENTS (Continued) .

Section

-T_itle P3 6.0 N0E INSPECTABILITY 6-1 6.1 Ultrasonic Braze Inspection 6-1 6.1.1 Principle of Operation , 6-1 i

6.1.2 Ultrasonic System 6-2

~

6.2 Eddy Gurrent Inspections 6-5 y ,

6.3 Susuery 6-10 7.0 ALARA CONSIDERATIONS FOR SLEEVING OPERATIONS 7-1 7.1 ROSA Sleeving Operations 7-2 ,

7.2 --Manipulator End Effectors 7-2 .

7.2.1 Sleeve / Tooling End Effectors 7-2 7.2.2 -In-Process Operations 7-3 7.3 Control Station in Containment 7-3 7.4' Potentials for Worker Exposure 7-3 7.4.1 Nozzle Cover and Camera Installation /Rencval 7-4 7.4.2 Platform Setup / Supervision 7

• 7.5 Radwaste Generation

• 7-5 7.6 Airborne Releases 7-7 7.7 Personnel Exposure Estimate 7-7 ~.

8.0 INSERVICE INSPECTION PLAN FOR SLEEVE 0 TU8ES 8-1 1819c/0235c/031185:5 5 tv

1 O-LIST OF TABLES .

. Table Title Page 3.1-1 ASME Code and Regulatory Requirements 3-3 3.3.2 Summary of Corrosion Comparison Data for 3-12 Thermally Treated Inconel Alloys 600 and 690 -

g .

• 3.3.2-2 Effect of-Oxidizing Species on the SCC Suscepti- 3-13 bility of Thermally Treated T-600 and I-690 C-rings ine Deaerated Caustic.

3.3.2-3 Test Program Objectives 3-14 3.3.2-4 Metallurgical / Corrosion Objectives and Test Performed 3-15

. 3.3.2-5 Summary of Previously Conducted Sleeve Corrosion and 3-16 Metallurgical Evaluation Program for Brazed Sleeves 3.3.2.1-1 Acceptance Criteria for Microstructure Characterization of Brazed Joint Area '

3-25 3.3.2.1-2 Summary of Grain Size Measurements 3-26 0

3.3.2.1*-3 Results of Controlled Potential Testing of Brazed 3-27 Inconel Alloy 690 Sleeves 3.3.3.3-1 Allowable Leak Rates For Model 51 Steam Generators 3-35 4

3.3.3.4-1 Test Results for the Model 44 As-rolled Lower 3-36 Joints

. 3.3.4.2-1 Test Matrix for Braze Joint 3-39

~

-3.3.4.3-1 Test Results for Braze Joint 3-40 1819c/0235c/031185:5 6 y

1 i

i LIST OF TABLES (Continued) .

Table -l Title Page .

3.4.4-1 Criteria for Primary Stress Intensity Evaluation 3-54 -

(Sleeve) 3.4.4-2 Criteria for Primary Stress Intensity Evaluation 3- 55 .

(Tube) , ,

3.4.5-1 Operating Conditions -

3-56 3.4.7.1-1 Umbrella Pressure Loads for Design, upset, Faulted, and Test Conditions 3-57 3.4.7.1-2 Results of Primary Stress Intensity Evaluations 3-58 Primary Membrane Stress Intensity, P, 3.4.7.1-3 Results of Primary Stress Intensity Evaluations - 3-59 Primary Membrane Plus Bending Stress Intensity. -

P,+P' b d

3.4.7.2-1 Pressure and Temperature Loadings for Maximum 3-60 Range of Stress Intensity and Fatigue Evaluations 3.4.7.2-2 Results of Maximum Range of Stress Intensity 3-62 Evaluation i

3.4.7.3-1 Results of Fatigue Evaluation 3-63 3.5.4-1 Regulatory' Guide 1.121 Criteria 3-67 4.0-1 Sleeve Process Sequence Summary 4-2 7.5-1 Estimate of Radioactive Concentration in 7-6 Water per Tube 1819c Vi

1 LIST OF FIGURES .

, Figure Title Page

. 2.2-1 Sleeving Boundary [ ]a,c,e Sleeves 2-3 3.2-1 Reference Sleeve Design 3-4 3

3.2-2 Sleeve Lower Joint Configpration . 3-5 3.3.2-1 SCC Growth Rate for C-rings ('150 percent YS and 3-18 TL7) in 10 percent NaOH 3.3.2-2 Micro Structure 3-19

^3.3.2-3 SCC-Depth for C-Rings (150 percent YS) in 3-20 8 percent Na 50 2 4 3.3.2-4 Reverse U-bend Tests at 360*C (680*F) 3-21 3.3.2.2-1 Location and Relative Magnitude of Residual 3-29 Stresses Induced by Expansion '

3.3.3.1-1 Lower Joint As-rolled Test Specimen 3-41 3.3.4.1*-1 Sleeving Mockup 3-42 3.3.5.1-2 HEJ Specimens for the Reverse Pressure Tests 3-31 3.3.6.1-1 Fixed-Fixed Mockup 3-44 3.4.2-1 Sketch of Brazed Sleeve Design 3-53

, 4.5.2-1 A Typical UT Inspection Trace 'of a Braze Joint 4- 12

~

4 vii 1819c/0235c/031185:5 8

1 LIST OF FIGURES .

Figure' Title Page .

6.1.1-1 Ultrasonic Testing of the Brazed Joint 6-12 .

C.1.1-2 Response of Focused Ultrasonic -Transducer 6-13 6.1.2-1 U1trasonic Scan of Braze Rpgton Sample M5 6-14 6.1.2-2 Ultrasonic Scan of Braze Region Sample le 6-15 e

~

6.1.2-3 Double Wall Radiograph of Calibration Specimen M5 6-16 6.1.2-4 Double Wall Radiograph of Calibration Specimen MB 6-17 6.1.2-5 Ultrasonic System Resolution Reference 6-18 6.1.2-6 Ultrasonic Inspection Process 6-19 6.2,1 Eddy Current Signals from the ASTM 6-20 Standard, Machined on the Tube 0.0. of '

the Sleeve / Tube Assembly Without Expansion (conventional Differential Coil Probe) 6.2.2 Eddy Current Signals from the 6-21 Expansion Transition Region of the Sleeve / Tube Assembly (Conventional Differential Coil Probe) 6.2.3 Eddy Current Calibration Curve for ASME 6-22 Sleeve Standard at [ ]a,c.e with the Conventional Differential Coil

~

Probe 1819c/0235c/031185:5 9 Viii

c- -

1 LIST OF FIGURES

, Figure -Title Page 6.2.4 Eddy Current Signals from the ASTM 6-23 Standard, Machined on the Sleeve 0.0.

of the Sleeve / Tube Assembly Without Expansion g . '

6.2.5 Eddy Current Signals from the ASTM 6-24 .

Standard, Machined on the Tube 0.0.

of, the Sleeve / Tube Assembly.Without Expansion ( Cross Wound Coil Probe ) ~

6.2.6 Eddy Current Signals from the Expansion 6-25 Transition Region of the Sleeve / Tube Assembly ( Cross Wound Coil Probe )

l .

6.2.7 Eddy Current Calibration Curve for ASME 6-26 Tube Standard at [ ]a,ce and a

. Mix Using the Cross Wound Coil Probe 6.2.8 Eddy Current Signal from a 20 Percent Deep 6-27 Hole, Half the Volume of ASTM Standard, Machined on the Sleeve 0.0. in the Expansion Transition Region of the Sleeve / Tube Assembly (Cross Wound Coil Probe) 6.2.9 Eddy Current Signal from a 40 Percent ASTM 6-28 Standard, Machined on the Tube 0.0. in Expansion Transition Region of the Sleeve / Tube Assembly (Cross Wound Coil

. Probe) ix 1819c/0235c/031185:5 10

1 LIST OF FIGURES ..

Figure Title P_aage .

6.2.10 Eddy Current Response of Square and 6-29 .

Tapered Sleeve Ends Compared to the Expansion Transitions for the -

Conventional Bobbin Coil Probe g . '

6.2.11 Eddy Current Response of the ASTM Tube 6-30 Standard at the End of the Sleeve using the, Cross Wound Coil Probe and Multifrequency Combination 6.2.12 Eddy Current Signatures of the Braze Region 6-31 6.2.13 Eddy Current Signatures of the Braze Region 6-32 6.2.14 Braze Region Geometry used to Generate Eddy 6-33 Current Braze Signatures .

6.2.15 100 KHz Eddy Current Signatures for Various '

6-34 Braze Widths and Braze Thickness 6.2.16 Effect on E.C. Braze Response of 1/4" EDM lootch 6-36 Thru the Tubewall

(

I 1819c/0235c/031185:S 11 X I

-- s , - . - . _ . - . _ . _ _ , . . . - _ , , . . . , . , _ , . . _ _ _ . . . _ _ , _ . . _ _ - _ - . _ _ , _ . . , _ . . _ . _ _ _ _ _ , - _ _ . . . , . _ _ , , _ _ _ _ , . -

1.

1.0 INTR 000CTION ,

As part of its ongoing steam generator repair programs, Westinghouse has developed the capability to restore degraded steam generator tubes by means of a sleeve. This technology may be applied to the steam generators of Prairie Island Units 1 and 2 with the objective of restoring the pressure boundary of such tubes and prolonging the availability of the steam generator heat exchange system. , ,

9 To date, nearly 15,000 steam generator tubes at six operating nuclear power plants world-wide have been successfully sleeved, tested, and returned to service by Westinghouse. . Both mechanical-joint and brazed-joint sleeves of Inconel. 600, Inconel 690, and bimetallic Inconel 625/Inconel 690 have been installed by a variety of techniques - Coordinate Transport (CT) system

~

_ installation, hands-on (manual) installation, and Remotely Operated Service 7 Arm (ROSA) robotic installation. Westinghouse sleeving programs have been

, successfully implemented .after approval by licensing authorities in the U.S.

(NRC - Nuclear Regulatory Commission) Sweden (SKI - Swedish Nuclear Power j .

Inspectorate), and Japan (MITI - Japanese Ministry of International Trade and Indus try).

8 i

The sleeving techno. logy was originally developed to sleeve 6,929 degraded tubes (including leakers) in a plant with Westinghouse Model 27 series steam generators. Process improvements and a remote sleeving system were subsequintly developed and adapted to a Westinghouse Model 44 series steam generator with utliization in full scale sleeving operations at two operating plants (2,971 and 3,000 sleeves). This technology has also been modified to facilitate installation of 2,036 sleeves in a non-Westinghouse steam generator. Most recently, the latest Westin4 house sleeving technology was successfully applied during a demonstration at a European site in a model 51 steam generator.

1 1819c/0235c/030885:5 12 g,g

l

. 1 2.0 SLEEVING OBJECTIVES AND SLEEVING BOUNOARIES ,

-2.1 '0BJECTIVES Both. Prairie Island Units are Westinghouse-designed 2 loop pressurized water reactors rated at 1650 MWt each. The two units utilize a total of four

~ vertical U-tube steam generators. The steam generators are Westinghouse Model 51 Series containing heat transfer tubes with gimensions of 0'875 inch nominal .

00' by 0.050 inch nominal wall thicknes's.

The sleeving co,ncept and design are based on observations to date that the tube degradation due to environmental attack has occurred near the tubesheet '

areas of the tube bundle. ' The sleeve has been designed to span the degraded region in order to maintain these tubes in service.

The sleeving program has two primary objectives:

1. To sleeve tubes in tNe region of known or potential tube degradation.

1.

2. .To minimize the radiation exposure to all working personnel (ALARA) s

%.2 SLEEVING BOUNDARIES Tubes to be sleeved will be selected by radial location, tooling access (due to channel head geometric constraints), and eddy current indication elevations and size. An axial elevation tolerance of one inch will be employed to allow for any potential eddy current testing position-indication inaccuracies and degradation growth. Tube location on the tubesheet face, tooling dimensions, and tooling access permitted by channelhead bowl geometry define the sleeving boundaries. Figure 2.2-1 shows an estimated radial sleeving boundary for a

[ ]*'C sleeve as determined by a geometric radius computed from the channelhead surface-to-tubesheet primary face clearance distance minus the

, tooling clearance distance. (The actual "as is" bowl geometry will be ~ '

slightly different in certain areas.) This is the sleeving boundary for a generic Westinghouse series 51 steam generator and represents the maximum Lsleeving potential with a [ ']a.c.e sleeve. This information along 1819c/0235c/030885:5 13 '

2-1 4

, . , - - .,,,.--m-~m , m--~n--en--n - - - ----c-,-, -, ,-n_. v-

--r- , - - + - - - - - - a ,. ,, , --m-y -

I 1

with addy current inspection data provides the inputs to evaluate each tube as a candidate for the sleeving process. Tubes within the sleeving boundary that .

are' degraded beyond the plugging limit but not within the axial restrictions of the [

Ja.c.e sleeve or not within the radial sieeving boundary will .

be plugged. The actual sleevable region may be decreased based on tool length.

The actual tube plugging / sleeving map for each steam generator will be provided as part of the software deliv,erables 9t the conclusion of the sleeving effort.

The specific ti$es to be sleeved in each steam generator will be determined based on the following parameters: ~

1. feo opposite channelhead side tube indications and no indications at an elevation not spanned by the sleeve pressure boundary which are greater than the plugging limit.

2. Concurrence on the eddy current analysis of the extent and location of the

, degradation. .

4 e

- 1819c/0235c/030885 :5 14 2-2

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1 l

a,c.e

[ ] SLEEVING TUBESHEET CLEA'RANCE RADIAN OUTLINE SERIES 51

' a,c.e .

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[ OU IDE REGION SLEEVE REGION 1946 I442 .

! TOTAL TUBES- 3388 l 1 I j

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i g .. .. - . _ _ _ _

g _ _ _

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-15

- ~ ~ ~ ~ ~ ~

i l : l  ;

- ~ ~

1 l .

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i s ~

l l -s

? - -

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. [ITITETTR E' s a a m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m m u m m m m m m m m m m mi m m m m m mlm.' m a m ag'gTEIERTE l I I I I I I I I I I I I I I I I I I l se es es is is as as ss ss is is 35 ss 25 2s is is 6 I

i j Pigure 2.2-1 t,

• I . ,

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b

. ^~

1 v N- 3.0 OESIGN ,

,y % ..

3.1 St.EEVE DESIGN DOCUMENTATION ',

. The Prairie Island steam. generators were built to the 1965 edition of Section III of the ASME iBoiler and Pressure Vessel Code, however, the sleeves' have 6Ieen designed and analyzed to the 1983. edition of Section III of the Code 1  :

- through the sunner 1983 addenda as well as applicable Regulatory Guides. The

+-

, associated materials and processes also meet the requirements of the Code.

' . The specific documentation applicable to. this program are listed in Table 3.1-1. ,

, 3.2 SLEEVE DESIG4 DESCRIPTION q .

The refarence design of the sleeve, as installed, is illustrated in Figure 3.2-1. [ '

3 ;

)a,c,e ,

At the upper end, the sleeve configuration (see Figure 3.2-1) consists of a section which is [

b 1819cIO23Scl030885:5 15 3-1 i

' b i

. -=c i! I l

~

~

i!

5 -

]a.c.e Theolower end of the sleeve has a preformed section to

~ g facilitate the seal fonnation and to reduce residual stresses in the sleeve. -

i The sleeve, after installation, extends above the top of the tubesheet and l l spans the degraded region of the original tube. Its length is controlled by the insertion clearance between the channel head inside surface and the

~-

primary side of the tubesheet, and the tube degradation location above the .

tutesheet. The remaining design parameters such as wall thickness and material are selected to enhance design margins and corrosion resistance . x and/or to meet ASME Boiler and Pressure Vessel Code requirements. The upper =

q joint is located to provide a length of free sleeve above it. This length is j added so that if the existing tube were to become severed just above the upper , i edge of the brazed joint, the tube would be restrained by the sleeve and . --

e#

j therefore axial motion, and subsequent leakage, would be limited. Lateral y motion wo*ld u also be restricted, protecting adjacent tubes from impact by the j severed tube. _

l To minimize stress concentrations and enhance inspectability in the area of g the upper expanded region, [ '

g 3,a,c.e.f  ;;

. =

3 The sleeve material, thermally treated Inconel 690 or 600, is selected to provide additional resistance to stress corr'osion cracking. (See Section 3.3.2 '. ]

for further details on the selection of thermally treated Inconel 600 and 690). [ _

3 -

i 1819c/0235c/030885:5 16 3-2 $

4 l2 5

\

g. .

l TABLE 3.1-1 .

,, ASME CODE ANO REGULATORY REQUIREMENTS

., Item Applicable Criteria Requirement Sleeve Design Section III- h8-3200, Analysis N8-3300, Wall Thick-

, , ness

.,_ Operating Requirements Analysis Conditions Reg. Guide 1.83 S/G Tubing Inspec--

tibility Reg. Guide 1.121 Plugging Margin Sleeve Material Section II Material Composition v ..

Section III NS-2000, Identifica-tion, Tests and ExaminationsSection IX Braze Material Code Case N-20 Mechanical Proper-ties Sleeve Joint 10CFA100 Plant Total Primary-Secondary Leak Rate Technical Specifications Plant Leak Rate Secticn IX Brazing Requirements Code Case N-421 Application of Radiant Brazing f-1819c/0235c/030885:5 17 3-3

r 1

~

a,c.e

) . .

e 1383c/0174c/112934:5 3-4

n: ,

- .; r , - e

..e._

m;> - - _

t ci: -

e.

Ma !- _ , ,

.cr , -

, s . .. .

. ~ , , . .;

e -

e. e. e. f .

.eg'#

s,} ' " c.

co.

+-

.,.,w h- 4 a  %

l

-e

~

s'w. ;_w

, .:;g .

s.. . . , - .

.a -

} --

r s. ^

< ~

4 L .. ,

1 sn v. . , - ,

st:

a O ..

y

=.

~

e-

~

1 <

. Figure 3.2-2 ,

~

. . . . Sleeve Lower Joint' Configuration 9

'h*

.gP a.k,

""2 3-5

3. . . ,

I 4

t,

-1

- - 1 4

3.3 DESIGN VERIFICATION: TEST PROGRAMS . l

)

3.3.1. DESIGN VERIFICATION TEST PROGRAM

SUMMARY

The following sections describe the material and design verification test programs. The purpose of these programs is to verify the ability of the sleeve concept to produce a sleeve capable of spanning a degraded region in a steam generator tube and maintain the s, team generator tubing primary-to-secondary pressure boundary under normal-and accident conditions. This

- program includes assessment of the structural integrity and corrosion resistance of slpeved tubes.

A substantial data base exists from previous test' programs which verifies sleeve design and process adequacy. Much of this testing is applicable to this sleeving program. The sleeve materials to be used, thermally treated nickel-chromium-iron alloys (Inconel 600 or 690), are identical to those used in prior sleeving programs. The standardized mechanical sleeve design is the .

same as that used in prior sleeving programs. The fabrication of sleeve / tube jointsby[ ]#'C has been .

verified in previous programs. Rigorous mechanical testing programs were conducted to verify the sleeve design for various steam generator models, including the Model 44, which has the same tube dimensions as the Model 51.

In addition to being dimensionally similar, analysis has demonstrated that the -

, operating conditions of a Model 44 steam generator envelope those of a Model

51. The$tfore, much of the Model 44 testing is directly applicabla to the Model 51 steam generators.

The objectives of the mechanfeal testing programs included:

- Verify that the leak resistance of the upper and lower sleeve to tube joints meet the leak rate acceptance criteria.

~

Verify the structural strength of the sleeved tube under normal and .

accident conditions.

1819c/023Sc/030885:5 18 3-6 1

1

-- -n-* r ,- --,-m---. --_r, , , , . ,- , _ , , . - , , .- .e -, -, , , , . - - - - , n p. - - - -gr-,.

l

.1 l

1

. Verify.the fatigue strength of the sleeved tube under transient loads  !

r'epresenting the remaining life of the plant.

)

Confirm capability to perform sleeving under conditions such as deep

~

secondary side hard sludge and tube support plate denting Establish the process parameters required to achieve satisfactory installation and performance. These parameters are discussed in Section 4.6. .

The acceptance criteria used to evaluate the sleeve performance are leak rates

' ~

based on the plant technical specifications. Numerous test specimens were used in the various test prograns to verify the design and the process 1 parameters. Testing encompassed static and cyclic pressures, temperatures,  ;

and ?oads. The testing also included evaluation of joints fabricated using Inconel 600 sleeves as well as Inconel 690 sleeves in Inconel 600 tubes.

While the bulk of the original qualification data is centered on Inconel 600 sleeves, a series of limited scope verification tests were run using Inconel 693 sleeves to demonstrate the effectiveness of the joint formation process and design with either material.

.The sections that follow describe those portions of the corrosion (sections 3.3.2) and mechanical (sections 3.3.3-3.3.5) verification programs that are relevant to this sleeving program.

3.3.2 CORROSION AND METALLURGICAL EVALUATION PROGRAM

, The basic objective of the corrosion and metallurgical evaluation programs conducted was to verify that the sleeving c5ncepts and procedures employed did not introduce any new mechanism that could result in premature tute or. sleeve

~ degradation.

~

, Inconel Alloy 600 and Inconel Alloy 690 (I-600 and I-690) are austenitic nickel-base alloys. I-600 has been extensively used, originally in the mill annealed condition, as steam generator tubing in pressurized water reactors.

1819c/0235c/030885:5 19 3-7 l

I 1

- , , . . , - - , , . - _n...,,,..-,n. , , , , . . - . . . - - , - . , - . , . . , , + , - - - . , , ,-

1 In recent years, attempts to enhance the IGA-SCC (Intergranular, Attac'k-Stress Corrosion Cracking) resistance of I-600 have focused on the application of a

~

themal treatment in the carbide precipitation temperature range (593* to 760*C). Microstructural modifications have concentrated on-the grain boundary ,

region since the SCC morphology in I-600 is predominantly intergranular. The maximum enhancement in caustic and primary water SCC performance was correlated with the presence of a semicontinuous grain-boundary carbide precipitate.

) .

• Inconel Alloy 690, which contains a higher. chromium content-(30 percent) than Inconel Alloy 600 has also indicated the ability to exhibit improved IGSCC resistance when thermally treated in the carbide precipitation region. -

The stress corrosion cracking performance of thermally treated (TT) Inconel Alloys 600 and 690 in oath off-chemistry secondary side and primary side environments has been extensively investigated. Results have continually demonstrated the additional stress corrosion cracking resistance of ,

j therinally-treated Inconel Alloys 600 and 690 compared to mill annealed Inconel l Alloy 600 material. Direct comparison of thermally treated Inconel Alloys 600' ,

I ' and ,690 has further indicated an increased margin'of SCC resistance for thermally treated Inconel Alloy 690. (Table 3.3.2-1). ,

.The caustic SCC perfomance of mill annealed and thermally treated Inconal Alloys 600 and 690. were evaluated in a 10 percent NaOH solution as a function

' of tenperature from 288'C to 343*C. Since the test data were obtained over various exposure intervals ranging from 2000 to 8000 hours0.0926 days <br />2.222 hours <br />0.0132 weeks <br />0.00304 months <br />, the test data were normalized in tems of average crack growth rata detemined from destructive examination of the C-ring test specimens. No attempt was made to distinguish between initiation and propagation rates. -

The crack growth rates presented in Figure 3.3.2-1 indicate that thermally treated I-600 and I-690 have enhanced caustic SCC resistance compared to that of I-600 in the mill annealed condition. The performance of thermally treated -

I-600 and I-690 are approximately equal at tenperatures of 316*C and below.

At 332*C and 343*C, the additional SCC resistance of thermally treated Inconel 1819c/0235c/030885:5 20 3,3

)-

Alloy 690 is observed. - In all' instances the SCC morphology. was intergranular

. in nature. The superior performance of thermally treated I-690 at higher '

temperatures .is a result of a lesser temperature dependency.

T Testing in 10 percent NaOH solution at 332*C was performed to index the relative intergranular attack (IGA) resistance of I-600 and I-690. Comparison of the IGA morphology for-I-600 and I-690 rings . stressed to 150 precent of the 0.2 percent yield strength is present,ed in Figure 3.3.2'-2. Mill annealed I-600 is characterized _by branching intergranular SCC extending from a 200u

. front of uniform IGA. Thermally treated I-600 exhibited less SCC and an IGA front limited sto less than a few grains deep. Thermally tr,eated I-690 exhibited no SCC and only occasional areas of intergranular oxide

. penetrations, . limited to less than a grain deep.

The enh'ncement a in IGA resistance can be attributed to two factors; heat treatment and alloy composition. A characteristic of mill annealed I-600

-C-rings exposed to deaer.ated sodiin hydroxide environment is the presence of intergranular. SCC. along with uniform grain-boundary corrosion referred to as intergran'ular attack (IGA). The relationship between SCC and IGA is not well' established but it does appear that IGA occurs at low or intermediate stress levels and at electrochemical potentials where the general corrosion 8 '

. resistance of the grain boundary area is a controlling factor. Thermal treatment of I-600 provides additional grain boundary corrosion resistance along with additional SCC resistance. In the case of I-690, the composition providds an additional margin of resistance to IGA and the thermal treatment enhances the SCC resistance.

The addition of oxidizing species to deaerated sodium hydroxide environments results in-either a deleterious effect or nd effect on the SCC resistance of thermally treated I-600 and I-690 depending on the specific oxidizing specie and concentration (Table 3.3.2-2). The addition of 10 percent copper oxide to 10 percent sodium hydroxide decreases the SCC resistance of thermally treated

~

.. I-600 and I-690, and also modifies the SCC morphology with the presence of transgranular cracks. The exact mechanism responsible for these changes is not well understood, but it is believed to be related to an increase in the specimen potential, corresponding to a transpassive potential, which results 1819c/0235c/030885:5 21 3-9 l

l 1

i

p 1

-in an alternate cracking regime. The specific oxidizing specie. arid 'the ratio of oxidizing specie to sodium hydroxide concentration appear, to play an .

important role. By lowering the copper oxide or sodium hydroxide concentration, the apparent deleterious effect on SCC resistance is eliminated. .

Mill annealed and thermally-treated I-600 and I. 600 were also evaluated in a number of 8 percent sodium sulfate environments The room temperature pH g value, at the beginning of the test, was' adjuste using sulfuric acid and asuonia. Test results are presented in Figure 1.2-3. As the pH is lowered,.

decreased SCC resistance for mill annealed *and themally-treated I-600 is

-observed, but thermally treated I-690 material did not crack even at a pH of

~

2, the lowest tested.

The primary water SCC test data are presented in Figure 3.3.2-4. For the beginning of fuel cycle water chemistries,10 of 10 specimens of mill annealed I-600 exhibited SCC, while 1 of 10 specimens of thermally-treated I-600 had cracked. In the end of the ft.el cycle water chemistries, 7 of 10 specimens of .

mill annealed I-600 exhibited SCC, while 3 of 10 specimens of themally-treated I-600 had cracked. After 13,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> of testing, no SCC .

has been observed in the mill annealed or thermally-treated I-690 specimens in either test environment. '

Continuing investigation of the SCC resistance of I-600 and I-690 in primary water environments has shows mill annealed I-600 to be susceptible to cracking at' high fevels of strain and/or stress. Themal treatment of I-600 in the carbide precipitation region greatly improves its SCC resistance. The performance of I-690, both mill annealed and thermally treated, demonstrates highly desirable p'rimary water SCC resistance, presumably due to alloy composition.

The evaluation of the brazed sleeve design relative to material and corrosion Issues has been performed as part of previous sleeving programs. The sleeve

, material used for some of the previous sleeving programs was thermally treated '.

Inconel Alloy 600, while an alternate sleeving material that has been used was thermally treated Incon.1 Alloy 690. Sufficient comparison of corrosion perfomance data for Inconel Alloy 600 and 690 has been made which allows the l

1819cIO235c/030885:5 22 3-10 t .

m-

-1 previous ' testing results generated for brazed Inconel Alloy 600.to 'be

-applicable ' for brazed Inconel Alloy 690. The basic objectives of the corrosion and metallurgical evaluation programs were to verify that the sleeving concepts and procedures do not introduce any new mechanism that will result in premature. tube or. sleeve degradation. These programs consisted of appropriately designed material and corrosion tests addressing the microstructural conditions in both the sleeve and tube following the braze cycle (refer to Tables 3.3.2-3 and 3.3.2-4). Table 3.3.2-5 summarizes the 1- '

results obtained from previous sleeve verification programs.

f f'

m i

1819c/0235c/030885:5 23 3-11

1 Table 3.3.2-1 SLM4ARY OF CORROSION COMPARISON DATA FOR THERMALLY TREATED INCONEL ALLOYS 600 AND 690

1. Thermally treated monel 600 tubing exhibits enhanced SCC and IGA resistance in both secondary-side and primary-side environments when compared to the mill annealed condition.

2. - Thermally tneated Inconel 690 tubing exhibits additional SCC resistance compared to themal treated Inconel 600 in caustic, acid sulfate, and primary water environments.

3. The alloy composition of Inconel 690 along with a thermal treatment provides additional resistance to caustic induced IGA.

4 The addition of 10 percent Cu0 to a 10 percent deaerated NaOH environment reduces the SCC resistance of both thermal treated I-600 and I-690. Lower .

, concentrations of either Cu0 or NaOH had no effect, nor did additions of Fe 03 4 and $102 '

p

5. Inconel Alloy 690 is less susceptible to sensitization than Inconel Alloy

~600.

6. Inconel Alloy 600 and 690 have comparable pitting resistance. ,

B t

1819c/0235c/030885:S 24 3-12 e

]

Table 3.3.2-2 .

EFFECT OF OXI0IZING SPECIES ON THE SCC SUSCEPTIBILITY OF THERMALLY . TREATED I-600 ANO I-690 C-RINGS IN DEAERATED CAUSTIC Tenperature Exposure Environment (*C) Time (Hrs) I-600 TT I,-690 TT 10 Percent NaOH + 316 ,

4000 , Increased Increased 10 Percent Cu0- Susceptibility

• Susceptibility * ,

10 Percent NapH + 332 2000 ho effect ho effect 1 Percent Cu0 ~

1 Percent NaOH +- 332 4000 No effect ho effect 1 Percent Cu0 10 Percent Na0H + .316 4000 No effect, ho effect 0

10 Percent Fe3 4 10 Percent NaOH + 316 4000 ho effect No effect 10 Percent SiO '

2

• Intergranular and transgranular SCC. ,

~

1819c/0235c/030885:5 25 3-13

1

.j .*

TA8LE 3.3.2-3 .

TEST PROGRM 08JECTIVES MAIN ASPECTS OF THE METALLURGICAL /

, CORROSION PROGRAM FOR 8AAZE0 JOINTS e

~

o CHARACTERIZE MICR0 STRUCTURAL ANO MECHANICAL PROPERTY CHANGES OCCURRING IN THE TU8E ANO SLEEVE MATERIAL o VERIFY. CORROSION RESISTANCE OF BRAZE 0 AREA USING ACCELERATED LA80RATORY TEST TECHNIQUES AND ENVIRONMENTS .

a o VERIFY OVERALL CORROSION RESISTANCE OF TuSE/

SLEEVE SRAZED AREA UN0ER HEAT TRANSFER CON 0!TIONS IN SIMULATED PRIMARY AND SECONDARY-SIDE ENVIRONMENTS 1819c/0235c/030885:5 26 3-14

j s

TA8LE 3.3.2-4 . .

, METALLURGICAL / CORROSION OBJECTIVES AhD TESTS PERFORMED Issue Test / Environment

1. Effect of high temperature brazing cycle on:

a. Tensile properties of -

Tensile tube and sleeve

,. b. . Microstructure , Metallographic examination, hard-ness transverse, optical and scan- ,

ning microscopy

c. Possible sensitization of o Huey tube and sleeve

d. Possible diffusion of 00 SEM/0AX, microprobe analysis and contaminants bending

e. Corrosion resistance of Isothermal tube and sleeve

. o 10 percent NaOH o Sulfate

, o Chloride o Primary Water o Pure Water

• o AVT

2. Residual stress level o X-ray residual stress measure-

, ment o SCC

3. Effect of residual brazed flux o Pressurized capsule

- primary water

- AVT

4. Compatability of Au-Ni braze '

Isothermal Corrosion Tests alloy

5. Performance of tube / sleeve Model boiler brazed assemblies in simulated

~

primary and secondary-side environments

6. Corrosion impact of annulus Model boiler between sleeve and tube 1819c/0235c/030885:5 27 3-15 l

i

- - - .- . ~ , --,-,a -, ,,,~.,,,,.n- .,,,.g,--,., .,,,,-.+,,..,,,w,_ ,,--,,-n,-r , . , , . , ,-w-- ,. ,-- , . - . , _ . - , , , . , . . . . - , .

J- ,

) ,

a.c.e

) . .

t-

= . ,

5

, Figure 3.3.2 2. Light Photomicrographs !!!ustrating IGA after 5000 Hours Exposure of Inconel Altoy 600 and 690 C. Rings to 10% NaOH at 3320C (6300F).

l 3 19

- - , - - --.-e- - -- --,,--.-%,.. ,----,,,-v. -e-- . - . , - ..m--, . . - - - . . -, ...<--e,---,,c.mm-,-,.-- --+-...-4-m----.-- - .. - -

r 1

TABLE 3.3.2-5 (Continued) . .

3 .b.L a ,

-1 .

~

l A

e 1819c/0235c/030885:5 29 3-17

~

SCC GROWTH RATE FOR C-RINGS (150% YS AND TLT)IN 10% NaOH Average Crack Growtit Rate ( gm/Hr.) Temperature ( F)

, 550 575 600 630 850 1 I i l I

O 1600 MA

• 1600 TT u i 690 TT '

y 10-3 --

E' -

-2 10 _

I 10' I I I I I I 200 300 310 320 330 340 350 -

_ ,,, Temperature ( C)

Figure 3.3.2-1

r- .

} - .

a.c.e t

! I . e I

t l

?

t-l l-l l

4 l'

i l- #

i i

. Figure 3.3.2 2. Light Photomicrographs Illustrating IGA after 5000 Hours Exposure of inconel Alloy 600 and 690 C Rings to 10% NaOH at 3320C (630'F).

3 19 I

i

SCC DEPTH FOR C-RINGS (150% YS)

IN 8% NA 2 SO 4 Maximum Crack. Depth,' gm -

Inches 1000 ^

.040 ,

80,000 ppm Na2SO4 800 -

332*C (630*F)

IN 600 MA -

.032 .

5000 Hours C-rings,150% YS g 600 -

.024 400 -

.016 IN 600 TT 200 -

IN 690 TT

.008

\ "T" I-I

_- z _

I I r k W" 2 3 4 5 6 7 10 .

Room Temperature, pH een ow.osee os Figure 3.3.2-3

- - -_a

7 i .-

l AEVERSE U-BEND ESTS AT 360 C (680 F) i BEGINNING OF FUEL CYCLE PRIMARY WATER j Cumulative Number Cracked i  % .

I 10 MAsm _

100 l

t 8 -

', 6 -

1 4 - -

50 2 - A

' ' TT se O

l l 0

1 l l l l 1 TT 690l MA 690 -

l  %

~ END OF. FUEL CYCLE PRIMARY WATER

] Cumulative Number Cracked  %

i . .

! 10 -

100 j 8 -

T "* "

{ 6 4 -

[ -

50 f TTeoo ,

2 -

s  ;

O ' *****""**

1 I I O

I I I I j O 2000 4000 6000' 8000 10,000 12,000 14,000

, , , _ , , _ , Exposure Time (Hours)

Pigure 3.3.2-4

i

.)

e .

3.3.2.1 ' CORROSION ANO METALLURGICAL EVALUATION OF THE BRAZED JOINT REGION'

1. Microstructural Characterization The objective of this phase was to determine the magnitude of any microstructural changes, to determine the level of sensitization within the brazed / heat affected zone areas, and to determine to what extent the 3- mechanical properties of the tube / sleeve material were altered. Acceptance criteria for each of these issues are presented in Table 3.3.2.1-1.

Microstructural changes were evaluated by grain size masurements. Changes in

~

the brazed and heat affected zones were campared to the unbrazed regions. Two brazed joints were axially sectioned at 60* intervals and metallographically examined. Grain size measurements were taken of both the tube and sleeve in the joint areas. Representative grain size masurements are presented in Table 3.3.2.1-2. (

]b,c',e All measured grain size numbers met the acceptance criteria. .

The level of sensitization within the brazed and heat affected zone was evaluated using the Reactivation Polarization tests. For these tests, a metallog aphically polished cross-section was passivated by maintaining the

, specimens potential in the passive range and then rapidly decreasing the electrode potential to the open circuit value. For no chromium depletion, the passive film remains intact; if chromium depletion is present, the passive film will break down at the chromium-impoverished region, causing rapid breakdown of the adjacent film. Optical microscopy examir.ation of the polished cross-section provides a direct inteipretation of sensitization. The acceptance criterion for sensitization using the reactivation polarization test is based on the metallographic appearance of the polished cross-section after exposure. (

1819c/0235c/030885:5 30 3-22 9

w-,

3 ja,c.e Reactivitation polarization tests performed on brazed joints produced using Westinghouse's current heat source techniques indicate [

.) * '

]b,ce Tensile tests performed on brazed joints indicate a (

,]D'C Based on ASME Section IX requirements for braze process qualification, the tensile strength of a brazed joint which fails outside of the braze nust not be more than 5 percent below the specified tensile strength of the base metal in the annealed condition. Tensile tests

~

performed on brazed joints at 600*F (316*C), as part of the ASME Code'

. Qualification for the Westinghouse braze process, indicated acceptable tensile strength. All Code requirements have been met.

2. STRESS CORROSION CRACK!hG RESISTANCE The brazing process for the upper joint introduces microstructural changes in both the mill annealed Inconel Alloy 600 tube and the newly installed sleeve.

Under isothermal conditions the corrosion arfd ,5CC resistance of specific regions within the brazed' area were evaluated and compared with the extensive data base which exists for both mill annealed and thermally heated Inconel Alloys 600 and 690. Specific areas evaluated were: 1) Areas exhibiting the largest degree of grain growth, 2) areas of the original mill annealed outer ~

tube which were affected by the braze cycle and remained as the primary ipressure boundary, 3) areas within the heat affected zone of the sleeve i

corresponding to the end of the braze alloy flow.

l

• 1819c/0235c/030885:5 31 3-23 k

1 C-rings taken from brazed joints in the specific areas noted ab,ove were

• exposedto[ ]"'Cundercontrolled

• potential conditions.

Evaluation of stress corrosion cracking (SCC) behavior using conventional inumersion tests usually involves prolonged test periods and often provides poor reproducibility from test.to test. Electrochemica11y controlled corrosion tests, which are designed to, allow thp metal potential to be controlled at known values, have the distinct advantages that SCC can often be initiated in days, that crack propogation rates can be increased by orders of magnitude, and $ hat reproducibility of test data is generally very good.

~

Controlled potential tests of a few days duration have been used to evaluate

, the relative SCC resistance of both mill-annealed and thermally treated Inconel Alloys 600 and 690.

The sleeve material, thebeally treated Inconel Alloy 690, has been shown to exhibit additional stress, corrosion cracking resistance to that of mill ,

anneated and thermally treated Inconel Alloy 600 material when hignty strained reverse U-bends were exposed to 680*F pure and primary water environments. ,

The stress corrosion cracking of thermally treated Inconel 690 in e off-chemistry secondary-side environments has been extensively investigated.

Results have continually demonstrated the additional stress corrosion cracking resistance of thermally-treated Inconel Alloy 690 compared to mill annealed and thermally treated Inconel Alloy 600 material.

Table 3.3.2.1-3 sunmarizes the results obtained for the controlled potential tests performed on C-rings cut from Inconel Alloy 600/Inconel Alloy 690 brazed joints. Results indicated no reduction in the SCC resistance of either the tube nor sleeve due to the' brazed cycle.

1819c/0235c/030885:5 32 3-24

I .

i, .

Table 3.3.2.1-1

ACCEPTANCE CRITERIA FOR MICROSTRUCTURE CHARACTERIZATION OF 8AAZE0 JOINT AREA M ,e i-7 l

g- . .

t 1

t  !

i I

I i

I

?

1

- I l ,

. .. t l

l l

. i

1819c/0235c/030885

5 33 3  !

i

i 1

Table 3.3.2.1-2 .,

SUMMARY

OF GRAIN SIZE MEASUREMENTS Axial Radial Grain z humber Location location (,) Tube sleeve

- b,c ,e i . .

e 4

l I

I i

l 4

i l

1319c/0235c/030885:5 34 3-26 f

_2

.) '

TA8LE 3.3.2.1-3 RESULTS OF CONTR0Lt.E0 POTENTIAL TESTING 0F 8AAZE0 INC0hEL ALLOY 690 SLEEVES TEST PARAMETERS a,b.c.e f

TEST RESULTS Maximum Crack C-ring Specimen Location, Depth (mils) b,c.e e

I I

l i

{

l 1819c/0235c/030885:5 35

! 3-27

...,-._____...,,.-,____.m~_

1 3.3.2.2 CORR 0$!0m A40 METALLURGICAL EVALUATION OF THE LOWER Jothi' All the dat4' presented in Section 3.3.2 relative to the corrosion and stress corrosion cracking resistance of thermally treated Inconel Alloys 600 and 690 .

J- are applicable to tiie sleeve. ,

The espansion processes for the lower joint involves a combination of 3 -( . e

~, , ,

.g_.

-\ .

• T , .

A -\g ..

]4.c.e The stresses in the ,

sleeve, based on tube to tubesheet data, should be as shown at S and C on t-Figure 3.3.2.21, which are also judged acceptable, particularly in view of .

. the* corrosion resistance of the thernefly treated sleeve material. Stress

, . c levels la the coser, tube are also influenced by the expansion techniquie. For an outer tube expansion produced ( '

ja.c.e Confirmation that the residual stresses at the tube 00 surface caused by the -

expansion 'were innocuous with regard to corrosion degradation was shown 6y accelerated controlled potential tests. s a

s 1

1319cl0235c/030485:5 36 3-28 s

9^ 4 1

v . +

3 ,

.. nos.s ta 3

.-cgl . >#

a. c. e 1

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. Figure 3. 3.2.2-1 ,

. Location and Relative Magnitude of Residual Stresses induced by Expansion f.

6 I*

i 3-29 V- , .

1 3.3.3 TEST PROGRAM FOR THE LOWER JOINT ..

3.3.3.1 OESCRIPTION OF LOWER JOINT TEST SPECIMENS The tube /tubesheet mockup was manufactured so 'that it was representative of the tube /tubesheet joint (Figure 3.3.3.1-1) of the nodel 44 and 51 steam generators. The tube was then examined with a fiberscope, [

3 .3a.c,e cleaned by swabbing, and re-examined with the fiberscope. ' Then the preformed sleeve (Thermally Treated Inconel 600 or Therinally Treated Inconel 690) was inserted into the tube and the lower joint formed. e C- .

ja.c.e 3.3.3.2 OESCRIPTION OF VERIFICATION TESTS FOR THE LOWER JOINT .

The as fabricated specimens for the Model 44 were tested in the sequence described belcw. Note that the tests of the Inconel 690 sleeve are similar to -

to those performed on the Inconel 600 sleeve except that the Steam Line Break (SL8) and E0P ( Extended Operation Period ) tests were not considered necessary based on previous results. As discussed in Section 3.3.1, Model 51 parameters and conditions are bounded by Model 44 parameters and conditions.

1. Initial leak test: The leak rate was determined at room temperature, 3110 psi and at 600*F,1600 psi. These tests established the leak rate of the lower joint after it has been installed in the steam generator and prior to long-term operation.

2. The specimens were f atigue loaded for [ ]a.c,e

3. The specimens were temperature cycled for ( la.c.e 1819c/0235c/030885:5 37 3-30

, 1

4. The specimens were leak tested at 3110 psi roon tempera.ture 'and at 1600 ps t ~ 600*F.' This tistablished the leak rate after 5 years of simulated normal operation (plant heatup/cooldowi cycles) produced by steps 2 and 3.

Several specimens were removed from this test sequence at this point and were subjected to the E0P Test. See. Step 74 below.

5. The specimens were leak tested wh,ile being subjected to SLB conditions.

6. The specimens were leak tested as in ' Step i to determine the post-accident leak rate.

7. The E0P test was performed after Step 4 for three as-colled specimens.

e 3.3.3.3 LEAK TEST ACCEPTANCE CRITERIA L

Site specific or bounding analyses have been performed to determine the j allowable leakage during normal operation and the limiting postulated accident condition. The leak rate criteria that have been established are based on Technical Specifications and-Regulatory requirements. Table 3.3.4.3-1 shows

~

the leak rate criteria for the Model 51 steam generators. These criteria can be campared to the actual leak test results to provide verification that the j_ sleeve exhibits no leakage or slight leakage that is well within the allowable limits. Leak rate measurement is based on counting the number of drops leaking

• during a 10-20 minute period. Conversion to volumetric measurement is based on assiming 19.8 drops per milliliter.

~

t N

+

-1819c/0235c/030885:5 38 3-31 e

l 1

I l

3.3.3.4 RESULTS OF VERIFICATION TESTS FOR LOWER JOINT- . l l

The test results for the Model 44 lower joint specimens are presented in Table 3.3.3.4-1. These results apply to the model 51, since Model 44 conditions ,

bound Model 51 conditions. The specimens did not leak before or during fatigue loading. After five years of simulated normal operation das to

[

3 .

e Ja c.e All of the three as-rolled specimens were leak-tight during the Extended Operating Period (.EOP) test.

For the Inconel 690 sleeve tests the following were noted:

Specimens MS-2 (Inconel 690 Sleeve): Initial leak rates at all pressures and at normal operating pressure following thermal cycling were [ .

A ja,b,c,e Specimen MS-3 (Inconel 690 Sleeve): [

Ja,b,c.e Specimen MS-7 (Inconel 690 Sleeve): [

Ja,b,c.e 1819c/0235c/030885:5 39 3-32,

3.3.4 TEST PROGRAM FOR THE BRAZE 0 JOINT , ,

The major part of the test orogram for the braze joint consisted of showing

, that a continuous braze band was produced by the brazing process.and satisfac-tory results were obtained when the joint was tested for braze joint e qualification in accordance with ASME Boiler Code,Section IX.

3.3.

4.1 DESCRIPTION

OF BRAZE 0 JOINT SPECIMEN 5

\

The braze joints were fabricated in the mockup shown in Figure 3.3.4.1-1. The tubes were [

]b,c.e The sleeve was inserted into the tube and sleev!ng operation was performed as discussed in Section 4.0.

After ultrasonic testing JUT) of the braze zone, a section of the sleeve / tube was cut for mechanical strength testing.

3.3,

4.2 DESCRIPTION

CF VERIFICATION TEST FOR THE BRAZE JOINT The test matrix is represented in Table 3.3.4.2-1.

3.3.4.3 RESULTS OF VERIFICATION TESiS OF, BRAZE JOINTS .

All specimens showed presence of continuous braze bands. Accordingly, all of the ten specimens were leaktight. Previous tests have shown that leaktight braze joints with continuous braze band remained leaktight as fatigue cycling, temperature cycling and SLB loads are imposed ori them. Based on such previous experiences, these' tests were not repeated on these joints. [

]a,c.e These tests also bound the model 51 steam generator conditions.

1819c/0235c/030885:5 40 3-33

1 C . .

ja.c.e 3.3.5 EFFECTS OF SLEEVING ON TuSE-TO-TU6ESHEET WELD e The effect of [ .

g . i ja,b,c.e 6

3.3.6

SUMMARY

OF TEST RESULTS Inconel 600 sleeves installed in the past in accordance with the design ,

process exhibited average leak rates of [ 3a.c.e whereas Inconel 690 steaves installed by the same process had [ 3a,c.e onder normal operating conditions after comparable testing. The leak rate exhibited by Inconel 600 sleeves was [ ]a,c.e of the allowable per sleeve leakage The leak rate for the con)inuous braze band joint is

[ ].a,c.e In general, the average leak rate for lower joints was

, unaffected by thermal and fatigue cycling. Strengths of both lower and braze joints had values exceeding any ' loading that is expected to occur during the steam generator operation.

1819c/023Sc/030885:5 41 3-34

w-g . . -

2

^

TA8LE 3.3.3.3-l. , ..

n.

ALLOWA8LE LEAK RATES FOR TYPICAL' MODEL 51 STEAM' GEERATORS (hermal Operation) ,'

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TABLE 3.3.4.2-1 . .

. TEST MATRIX FOR BRAZE JOINT Number of Specimens Test a,c e t

. e 8

4 1819c/0235c/030885:5 43 3-39

3 TA8LE 3.3.4.3-1 TEST RESULTS FOR BRAZE JOINT (INCONEL 600 TUBE /INCONEL 690 SLEEVE)

UT Inspection- Ultimate Tensile ,

Specimens No. Continuous Strength (psi) b,c.e

) . '

d 1819c/0235c/030885:5 44 3-40 4

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. =

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A- . nos.n 1 Sc. . .

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s' FIGURE 3.3.3.1-1 Lower Joint As-Rolled "

Test Specimen 3-41

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3 3.4 ANALYTICAL VERIFICATION . .

3.4.1 Introduction This section etntains the structural evaluation of the sleeve and tube i assembly with brazed sleeves in relation to the requirements of the ASME Boiler and Pressure Vessel Code, 5ection III, Subsection h8,1983 Edition

'(Reference 1) , ,

The analyses include primary stress intensity evaluttions, maximum range of

stress intensity evaluations, and fatigue evaluations for various mechanical

~

and thermal conditions which umbrella the loading conditions specified by the Westinghouse Equipment Specification G-677164,12/18/69, Revision 1 (Reference 5), Whstinghouse Equipn. tnt Specification Addendum No. .677030, 11/12/73, Revision 3 (Reference 6), and Westinghouse Equipment Specification Addendum

-No. 952404, Revision 1, 3/21/71 (Reference 7).

3.4.2 Camponent Description A sket:h of the [ 3a,c,e sleeve design is presented in Figure 3.4.2-1.

.The main portions of the sleeve-tube assembly are the two joints, [

, ga,c.e

[

.]'C The load conditions imposed on the models were consistent with those for the sleeve on the hot leg side. The tolerances used in developing the nodel were such that the maximum sleeve and tube outside

~

disneters were evaluated in combination with the minimum sleeve and ttbe wall thicknesses. This allowed maximum stress levels to be developed in the.

reg ions . analyzed.

i 1819c/0235c/030885:5 45 3,43

.. _ _ _ , _ - - _ , , _ _ _ _ _ . . . . _ ~ , . _ _ _

WESTINGHOUSE PROPRIETARY CLASS 2 3.4.3 Material Procerties The sleeve material is Inconel 690 or Inconel 600. Both sleeve materials Inconel 690 and Inconel 600 are covered by ASME Code Case N-20 (Reference 8].-

The tube material is58-163 (Inconel 600). ,

All material properties used in the analyses were as specified in the ASME Soiler and Pressure Vessel Code,Section III, Appendix ! (Reference 4) and Code Cases (Reference 8).

3.4.4 Code Criteria The ASME Code stress criteria which must be satisifed are given in Tables 3.4.4-1 and 3.4.4-2.

3.4.5 Loading Conditions Evaluated The loading conditions are specified below:

1. , Design conditions 4

. a. Primary side design conditions P = 2485 psig T = 650*F .

b. Secondary side design conditions P = 1085 psig T = 600*F

c. Maximum primary to secondary pressure differential - 1600 psig, '

T = 650*F

d. Maximum secondary to primary pressure differential - 670 psig, -

T = 650*F 1819c/0235c/030885:5 46 3 44 I

l l

I

.y, v_____,. ,__,,__., ,- , - . - . . , - ,. - - . - ,

3

2. Full load steady state conditions are: . .

, Primary side pressure = 2235 psig Hot leg temperature = 599.1*F

, Cold leg temperature - 535.5*F Secondary side pressure - 735 psig e Feedwater temperature = 427.3*F .

Steam tenperature = 510.8*F ,

Other operating conditions are specified in Table 3.4.5-1.

3.4.6 Methods of Analysis Using the WECAN (Reference 2) finite element analysis program, stress components were taken directly from the analysis of the tube-sleeve assembly.

Separate continuous unit pressure runs and thermal transient runs were first made and then properly combined with the WECEVAL (Reference 3) Program.

3.4.6.1 Model Deve.opment A finite element model was developed for evaluating the sleeve design, s

.Some significant considerations in developing the model were:

1. The[ ] space was modeled with f.inite elements which

.. were used for the tenperature calculations only, they were considered as dumray elements for all of the stress calculations.

2. The nodes along the [ ]a,c.e at the sleeve-to-tube intersection were coupled in all directions for both the thermal and ,

pressure / thermal stress analysis.

3. There is a [

, ,3a,c.e .

1819c/0235c/030885:5 47 3-45 i

I

- - _ , _ , , . - - - _ . - _ , - _ . _ _ , _ , _ _ - - _ , ,_y., ,m ,_., , _y,_ , - .,, _ , , , ,#.,-,......,.... .

\

4._ By varying the boundary conditions at a specified region of the-model, conditions were simulated for both an intact tube and a discontinuous-(severed) tube.

^

The element types chosen for the finits element analysis were thesg WECM (Reference 2) elements: ,

a,c.e s

)' .

' All the element types are quadratic, having a node placed in the

~

, center of each edge in addi. tion to the corner nodes.

4

).4.6.2 Thermal An'alysis The purpose of the thermal analysis is to provide the temperature distribution

. needed for thermal stress evaluation.

Thermal inalyses were performed for the following cases:

Plant loading / Unloading .

Small step load increase Small step load decrease large step load decrease Hot standby operations .

Loss of load Loss of power Loss of secondary flow Reactor trip from full power 1319c/0235c/030885:5 48 3-46 i

In order to perform the thermal analysis, boundary conditio'ns consisting af fluid temperatures and heat transfer coefficients (or film coefficients) for the corresponding element surfaces'were necessary. The conditions considered in the thermal analysis are based on the following assumptions: ,

The tenperature induced stresses are most pronounced for sleeves in the hot leg (where the ' temperature difference between the primary

-i and secondary fluids is a m'aximum) and therefore, only the hot leg

~

sleeves were considered. This. condition bounds the thermal stresses on the cold leg.

The sleeves may be installed in any tube in the generator. Thus, to be conservative, it is asstaned that the sleeve to be evaluated is sufficiently close to the periphery of the tube bundle that it experiences the water tanperature exiting the downcomer.

Special thermal and hydr'aulic analyses were performed to determine the primary and secondary side tenperature and film coefficients as a function of time.

Both boiling and convective heat transfer correl'ations were taken into consideration. ,

3.4.6.3 Stress Analysis A WECAft finite element model was used to ' determine the stress levels in the

, tube / sleeve / braze configuration.

Based on the results demonstrating the applicability of a linear elastic

, analysis, thermally induced and pressure induced stresses were calculated separately and then combined to determine the ' total stress distribution using

- the WECEVAL computer program (Reference 3). In addition, WECEVAL performs the stress categorization required for an ASME Boiler and Pressure Vessel Code Section !!I stress analysis and for the complete fatigue evaluation. -

The criteria in the evaluation were those specified in Subsection NS of the ASME Boiler and Pressure Vessel Code (Reference 1).

4 1819c/0235c/031185:5 49 3 47

-,-w -,--n-- * .- , p -n,-,,--,m--- - - , - - -g--w,,,-,v,-- ~sa -- - - - -

,---e---mv'T'- *-~~. "*~'r'w'~'

) . .

Pressure Stress Analysis

, The )ECM model of the sleeve-to-tube brazed joint was used to determine stress distributions induced separately by a 1000 psi primary pressure and a s

.1000 psi secondary pressure. The results of these " unit pressure" runs were then adjusted to the actual sleevt dimensions and the actual primary side and secondary side pressures corresponding to the Joading condition considered in order to determine the total pressure stress distribution. .

The modeling cases in determining the unit pressure load stress distributions

~

were tube intact and tube discontinuous. Therefore, the following unit pressure loading conditions were evaluated to determine the maximum

. anticipated stress levels induced by primary and secondary pressures:

Primary pressure - tube intact Primary pressure - t,ube discontinuous Secondary pressure - tube intact '

Secondary pressure - tube discontinuous

~

The end cap forces due to the axial pressure stress induced in the tube away from discontinuities were taken into consideration.

Thermal. Stress Analysis ,

g . .

The WECM model was used to determine the thermal stress levels in the tube / sleeve / braze configuration that were induced by the temperature distribution calculated by the thermal / hydraulic analysis. The times during the thermal transient solutions which were artti,cipated to be limiting from a .

stress standpoint were evaluated.

The thermal stress runs for those transients which were anticipated to give the largest contributions to the, maximum range of stress intensities and fatigue usage factors were performed using the Prairie Island finite element 2 model. These events were marked by three stars *** in Table 3.4.7.2-1.

3~"'

1319c/0235c/030885:5 50

• a-- . , , , , , _ , , . _ _ , , , _ _ , . _ . , ,,,.-.,y.,.,- _ . , , ,. - . , .__ , y.m.,

- - -e---- - _- _.w, . . ~ , . . _ _ , . . . , , _ , _ _ , . - . , . , , ,

i 1

l

.. I Thermal stress levels for the remainder of the transients were determined by

. scaling the results of'the thermal stress analysis for similar brazed sleeves.

Combined Pressure Plus Thermal Stress Evaluation e

As mentioned previously, total stress distributions were determined by combining the unit pressure and thermal stress results as follows:

P -

' total *

• I'I unit primary pressure P3 ,c

~

T005 I'I unit secondary pressure

• I'I thermal At any given point or section of the model, the WECEVAL program determines the total stress distribution for a given loading condition and categorizes that total distribution per the Subsection NB requirements. That is, the total stress of_ a given cross-section through the thickness is categorized into membrane, linear bending, and non-linear components. These categorized stresses are then compared to Subsection N8 allowables.

In addition, when supplied with a complete transient histoa y at a given location in the model, the WECEVAL program will calculate the total cumulative f atigue usage factor per Code Paragraph h8-3216.2.

3.4.7 Results of Analyses '

Analyses were performed for both intact and discontinuous tubes. Fatigue and stress analyses of the sleeved tube assembly have been completed in accordance with the requirements of the ASME Boiler and Pressure Vessel Code,Section III.

J 1819cl0235c/030885:5 51 3-49

3 3.4.7.1 PRIMARY STRESS INTENSITY ,, l l

The umbrella loads for primary stress intensity evaluation are given' in Table 3.4.7.1-1. ,

Primary stress intensity calculations were -performed using the formulas from N8-3324 of the ASME Code (Reference 1).

The results of primary stress intensity evaluation for the analysis sections ,

are swanarized in Tables 3.4.7.1-2 and 3.4.7.1-3.

All primary stress intensities for the sleeved tube assembly are well wi, thin allowable ASM Code limits.

The largest value of the ratio calculated stress Intensity / Allowable Stress Intensity of [

ja,b,c ,

3.4.7.2 RANGE OF PRIMARY ANO SECONOARY STRESS INTENSITIES Table 3.4.7.2-1 contains the pressure and temperature loads for maximum canc e of stress intensity evaluatl6ns as well as fdr , fatigue evaluations.

The maximum range of stress intensity values for the sleeved assemclies are sunnarized in Tables 3.4.7.2-2.

The requirements of the ASME Code, Paragraph N8-3222.2, were met directly at all locations and required no further consideration.

I 1319c/0235c/030885:5 ' 52 t

O-

3 3.4.7.3 RANGE OF TOTAL STRESS INTENSITIES . .

Based on the sleeve design criteria, the fatigue analysis considered a design life _ objective of 40 years for the sleeved tube assemblies. Table 3.4.5-1, lists the operating conditions considered in the fatigue analysis.

• The maximum fatigue strength reduction factor of 5.0 (h8-3222.4(e?)) was applied in the radial direction at th,e [ Jac.e tip points. Because of singularities created by the finite element mesh used in the calculations, a ,

fatigue analysis using linearized stresses from the maximum range evaluation was performed.

The results of the fatigue analysis for the sleeved tube assemblies are sunmarized in Table 3.4.7.3-1.

All of the cumulative usage factors are below the allowable value of 1.0 specified in the ASME Code.

3 ,

, l

~

1819c/0235c/03CS85:5 53

Ine

~

1 3.

4.8 REFERENCES

I

1. ASME Boiler and Pressure Vessel Code,Section III, Subsection N8,1983  ;

Edition, July 1,1983. l

2. WECAN, WAPPP and FIGURES II, F. J. Sogden Editor, Second Edition May 1981,- Westinghouse Advanced System Technology, Pittsburgh, PA 15235.

g . e

3. J. M. Hall, A. L. Thurman, J. B. Truitt, " Automated ASME Stress ,

l Evaluation Program WECEVAL, The Proceedings of the Fourth WECAN User's l Colloquium, Westin9 house, October 5,1979.

4. . ASME Boiler and Pressure Vessel Code,Section III, Appendix !.  ;

5. Equipment Specification G-677164, Westinghouse, July 10, 1969, Revision 1, December 18, 1969.

6. Equipment Specification Addendum No. 677308, Westinghouse, August 5, 1969, Revision 4, November 12, 1973.

~

7. A. J. Chapman . Heat Transfer, Macmillan Publishing Co., Inc. New York,

. Third Edition,.1974.

8. ASME Boiler and Pressurc Vassel Code, Code Cases, Case N-20,1983 Edition, July 1, 1983.

9.

~

Design Specification SGTO 10.1.4-002 (84), Westinghouse April 23, 1984, Revision 1.

3-52

• 1819c/0235c/030885:5 54 i

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s'ik J . TABLE l 3.4 4 1 g!TERfA FOR PR!PAaY STRt33 INTEN5ftY EVAh.UATION

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.:. TABLE. 3,4.4-2 CRITERf A FOR PRIMARY $7pggs ts7g..my g.,,gg,,

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TABLE 3.4.5-1 '

OPERATING CONDITIONS 1 .

l t NO. OF OCCURRENCES CONDIT!0rt TO BE, ANTICIPATED

_ s s.

' NORMAL,0PERATING CONDITIONS' , e Plant Heatup 200

• i Plant Cooldown 200 Plant-Loading S: Minute 18.300 -

Plant Unloading 55 Minute 18,300 Small Step Load increase 2,000 small Step Load Decrease 2,000 Large Sten Load Decrease 200 Hot Standby Operations '^18,300 Turbine Roll Test

• 10 -

Steady State Fluctuations =

s 4

UPSET CONDITIONS Loss of Load 80 Loss .of Power , 40 g- .. Less of Flow ~ 80

. Reactor Trip from Full Power 400 FAULTED CONDITIONS

• Reactor Coolant Pipe Break 1 Steam Line Break 1 Feed Line Break I TEST-CON 0!TIONS Primary Side Hydrostatic Test 5 Secondary Side Hydrostatic Test 5 3-56

-w e-, ,....-s -

. .w v 4 , , , - . . - . - - - - , - - . , , , , - - - - - . -,-,------y---.--m--

- - - - m - m

TABLE 3.4.7.1-1 ..

UMBRELLA PRESSURE 1.0 ADS FOR

- DESIGN, UPSET, FAULTED, AND TEST CONDTIONS o

a,c.e CONDITIONS .

) Design * '

L

, Design Primar:/ .

Design Secondary Upset-Loss of Load Loss of Power

. Loss of Flow .

Reactor Trip from Full Power

]l i

F'aulted

, Reacter Coolant P,ipe Break

-Steam Line Break Test Primhry Side Hydrostatic Test Secondary Side Hydrostatic TeYt  !

. l i

f. .

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• W VB

. f"1 E

& W W M C e *

. w M>

^

> > M >=

El 4 W **

>= E J E M ==. 8 w 3 ==. >= E M -

= E UMMwM

> k v

• w E e-4 C

M E .

>= 0. .

. sM w

3 M

E b

5 v

U .

4 b_ .E 4 w 8

.a 8

W e

3-58

TABLE 3.4.7.1-3 REsULTS OF PRIMARY STRESS INTENSI1Y EVALUATIONS PRIMARY MEMBRANE'PLUS BENDING STRESS INTENSITY, P,+ P b

CALCULATED MAXIMUM ALLOWABLE OF STRESS STRESS RATIO "

. INTENSITY, INTENSITY, CALCULATED S.I.

LOCATION CONDITIONS KSI KSI . ALLOWABLE S.I.

TUBE INTACT '

a,c,e y - -

3 .

G 4

a e

6 9

e 9

h*

9 '

.a -

~

TABLE 3.4.7.2-1 PRESSURE AND TEWERATURE LO/JINGS FOR MAXIMUM RANGE

,

• 0F STRESS INTENSITY AND FATIGUE EVALUATIONS a,c.e.

4

-g . .

• e 9

+

e e

• • . e '9 ,

~

TABLE 3.4.7.2-1 (Cont)

PRESSURE AND TEMPERATURE LOADINGS FOR MAXIMIM RANGE 0F STRESS INTENSITY AND FATIGUE EVALUATIONS

~

a,c.e N

h. .

e m

• 9 e

4 e

e Euw e

% g

A J J---+ A - 4 e 4

.)- . .

4

.[. '$'-'

U e .

Q . -.

G l.

w.

0

.)- 5 * '

8 .

~

t ll>

w m

E w

a- >

3

=

N W e M N W

• M h >

• M v . .

.a O

>e I

M B

m .

, ,- > s h

• w K

k e

e O

O 9

3-62

? 'l

e

L

't ;

^

4 0

, ' E G

A S

UR O 0 0 0 0 ET LC 1 1 1 1 8A AF W

O L

L

- A .

a N

O I

T A _

U .

L E e. .

A G c, 1 V A

- E S a 3 U E R 7 U E O G V T 4 I I C T T A 3 A A F F L O E U L F M B O U A C T S

- T L

U S m E

R

- e u '.

T C e A

N T O N I I T

A E C B O 0 L 1 g

p~ ,

3.5. SPECIAL CONSIDERATIONS ,,

3.5.1 FLOW SLOT HOURGl.ASSING Along the tube-lane, the tube' support plate has several long rectangular flow .

slots that have the potential to deform into an " hourglass" shape with significant denting. The.effect of flow-slot hourglassing is to move the neighboring tubes laterally inward to the tube lane from their initial positions. The eximum bending would occur on the innermost row of tubes in the center of the flow slots. The following discussion considers the effects of flow slot hourglassing on the sleeved tube.

3.5.1.1 EFFECT ON BURST STRENGTH

'The effect of bending stresses on the burst strength of tubing has been studied.- Both the axial and ciretsferential crack configurations were investigated. (

3a,e.f 3.5.1.2 - EFFECT ON STRESS CORROSION CRACKING (SCC)' MARGIN Based on the results.of the caustic corrosion test program on mill-annealed tubing, the bending stress-magnitude due to flow-slot hourglassing is judged to have only a small effect, if any, on the, SCC resistance margins. Two long term moddlar model boiler tests have been conducted to address the effect of

, bending stresses on SCC. No SCC or IGA was detected by destructive examination. It is to be noted that thermally treated Inconel 600 and Inconel 690 have additional SCC resistance conpared to mill annealed Inconel 600 tubing.

• 3.5.1.3 EFFECT ON FATIGUE USAGE In addition to the above two considerations, one should also consider the ~

effect of the hourglassing-induced bending stresses on the fatigue usage factor of the sleeve. This is included in the fatigue analysis by recognizing that the stress induced by this motion is a mean stress. Mean stress effects 1319c/0235c/030885:5 55 3-64 o

l are included in the S-N fatigue curve used in the analysis, hence hourglassing

. induced bending stresses are included in the fatigue' cnalysis.

1 3.5.2 TUBE VIBRATION ANALYSIS i I

- Analytical assessments have been performed to predict modal natural 2- frequencies .and related dynamic pending stresses attributed to flow-induced

vibration for sleeved tubes. - The pu,rpose of ~ the assessment was to evaluate the effect on the natural frequencies, amplitud; of vibration, and bending ,

_[ stress due to installation of various lengths of sleeves.

I Since the level of stress is significantly below the endurance limit for the

[ tube material and higher natural frequencies result from the use of a l sleeve / tube versus an unsleeved-tube, the sleeving modification does n,ot

.{ contribute to cyclic fatigue.

3.5.3 . SLUDGE HEIGHT THERMAL EFFECTS In general, with at least 2.0 inches of sludge, the tubesheet is isothermal at the bulk temperature of the primary fluid. The net effect of the sludge is to reduce tube /tubesheet thermal effects. -

3.5.4 ALLOWABLE SLEEVE DEGRADATION

, Minimum required sleeve wall thickness, 'tp , to sustain normal and accident

, condition loads are calculated in accordance with the guidelines of Regulatory Guide 1.121, as outlined in Table 3.5.4-1. In this evaluation, the

~

. surrounding tube .is assumed td be completely degraded; that is, no design credit is taken for the residual strength of ,the tube.

The sleeve material may be either thermally treated Inconel 600 or thermally treated Inconel 690. It has been shown that the properties of Inconel 600 are very similar-to those of Inconel 690. In particular, the yield strength and -

ultimate strength are very similar.

1819c/0235c/030885:5 56 3-65

l i . .

~

The pra.orties of I-600 were used in these analyses because the, data ' base for

~ I-60s is larger than the data base for I-690, thus allowing the use of a .

smaller tolerance factor.

4 i . .

O e

I-j.

1819c/0235c/030885:5 57 3-66 f.

3-

.~

Table 3.5.4-1 REGULATORY Gul0E 1.121 CRITERIA

1. Normal Operation i

Oetermine tr , minimum required sleeve wall thickness.

a. Yield Criterion: Sy1 39.59 ksi' Loading: Pp = 2213 psia .

.P3 = 636 psia AP = 1577 psi AP . R Hence, tr*5 y

- 0.5 (Pp

+P)*b s

"O which is [35]C percent'of the nominal wall thickness [of 0.039 r inches]C.

.i

b. 01 timate

, Criterion: S u1 90.58 ksi Loading: Pp = 2213 psia .

P3 - 636 psia AP = 1577 psi 4P R'

Hence, tp=3 =[ ] inch a,c.e i

[-0.5(P p+ Ps I'

/ which is [ ]a,c.e percent of the nominal wall thickness [

ja,c.e, ,

2. Accident Condition Loadings

a. LOCA + SSE l

The major contribution of LOCA and SSE loads is the bending stresses at the top tube support plate due to a combination of the support motion, inertial loadings, and the pressure differential across the

{

tube U-bend resulting fran the rarefraction wave during LOCA. Since '

the sleeve is located below the first support, the LOCA + SSE 1819c/0235c/030885:S 58 3-67

1 Table 3.5.4-1 (cont.) , ,,

bending stresses in the sleeve are quite small. The governing event for the sleeve therefore is a postulated secondary side blowdown. , ,

b. ~ FL8 + SSE .

) The maximum primary-to-secondary presqure differential occurs during a postulated feedline break (FLS) accident. Again, because of the , .

sleeve location, the SSE bending stresses are small. Thus, the governing stresses for the minimus wall thickness requirement are the pressure membrane stresses. -

. Criterion: P, < smaller of 0.75, or 2.45, i.e. 63.41 ksi Loadings: P, - 2650 psia P, s 0 AP . 2650 psi

- AP . R g Hence, t r

• o.I 5,- 0.5 (Pp +P)3 *b 3,,c,,

3: , Leak-Before-Break Verification The leak before break evaluatior, for the sleeve is based on leak rate and burst pressure test data obtained on [

]C cracked tubing with various amounts of uniform thinning simulated by machining on the tube 00. The margins to burst during a postulated SLB ( Steamline Break Accident ) condition are a function of the mean radius to thickness

• ratio, based on a maximum permissible leak rate o'f 0.35 gpm due to a normal operating pressure

-differential of 1500 psi. '

181gc/0235c/030885:5 59 3-68

+e - - . . . _ , . . . . - ----,,--r . - - . - -. ,,. -r - - -. -v - - . -

c-

}

Table 3.5.4-1 (cont.) , ,

A 25 percent margin exists between the burst crack length and th'e leak crack length. This margin was identified using a nean radius to thicknessfactorof[ ]a,c for the nominal sleeve, the ' current Technical

~

Specifications allowable leak rate of 0.35 gpm, a SLB pressure differential of 2560 psi, and the nominal leak and nominal burst curves.

For a sleeve thinned 54 perc'ent through wall over a 1.0 inch axiaf length, a 17 percent margin t'o burst is demonstrated. Thus the leak-before break' behavior is confirmed for unthinned and thinned -

conditions.

e l

1819c/0235c/030885:5 60 3-69 1

I 1

.m 1

n 1

3.5.5 'EFFECT OF TU6ESHEET/ SUPPORT Pt.A1E INTERACTION Since the pressure is normally higher on the prin.ary side of the tubesheet

- than on the secondary side, the tubesheet normally becomes concave upward.

Under this condition, the tubes protruding from the top of the tubesheet will rotate from the vertical. This rotation depends on the boundary condition assumed for the edge of the tubesheet. Previous calculations of the tubesheet deflection, using a finite element model of the tubesheet which includes the i

effects of the adjacent channel head arid the stub barrel,: resulted in a plot that is in agreement with the theoretical deflection formula for circular ~

plates with fixed edges, provided that the shear deflection is included.

Calculations showed that [ 3a.c.e This stress was added te the cyclic stress in the fatigue evaluation. Note that this stress can a ratioed to account for different ap's that occur in different events. However, the seismic stress, as shown above, is not critical to the fatigue us' age which was found to be low. '

3. 5.,6 COMPREHENSIVE CYCt.!C TESTING The Comprehensive Cyclic Test was designed to simulate the loadings produced by the heatup/cooldown and load / unload transients on the upper tube-to-sleeve joint.. This test was initially intended to be used f' conjunction with the Axial Shear Fatigue Test (a 5,000 cycle fatigue test) to evaluate the sealing integrity of the tube-to-sleeve joint after the application of cyclic loadings. They also would provide experimental confirmation of the capability of the joints to withstand fatigue loadings.

Based on analytical comparisons, the fatigue test produced fatigue that was

, substantially greater than that which would have been produced in the Comprehensive Cyclic Test. Also, the fatigue test produced more fatigue than was calculated to occur. due to the inservice transient conditions. There fore. -

it was detennined that the Comprehensive Cyclic Test was not needed in addition to the fatigue test in determining the fatigue integrity of the tube-to-sleeve joint.

1819c/023Sc/030885:5 61 3-70

g 3.5.7' EVALUATION OF OPERATION WITH FLOW EFFECTS OuE TO SLEEV,1NG

~

An ECCS performance analysis considering 5 percent uniform steam generator tube plugging, SGTP, has been completed for the forthcoming-Westinghouse fuel reload of the Prairie Island Units. - This safety analysis assumed up to 5 e percent tube plugging in the stean generators of either plant and took credit for the current 2.28 value of total core peaking factor. This study and the corresponding non-LOCA study are considered applicable for the steam generator sleeving program as regards Westinghouse-supplied fuel. The accidents ,

evaluated include LOCA and non-LOCA transients as well as consideration of the effects on the nuclear design and thermal-hydraulic performance wit'i the existing plant reactor internals. For the accidents considered in that study,

.the core and system parameters either remained within their proper limits (i.e., peak clad tapergture, ON8R, RCS pressure, etc.) or the impact of the additional tube plugging was shown to be negligibly small.

^

Inserting a sleeve into ,a steam. generator tube results in a reduction of -

primry coolant flow. The selected sleeving program at Prairie Island

' involves the 36 inch long sleeve. For a 36 inc;i sleeve located on the hot-leg stAe, the primary coolant flow loss per tube is'approximately equal to 3.0 percent of nomal flow. . This reduction in primary coolant flow equates to a

. hydraulic equivalency ratio of 33 sleeves to one plugged tube.

Using this ratio in conjunction with the, existing tube plugging level, the ,

. following tables are established for the maximum possible number of sleeves

, .(1,946 sleeves per steam generator). Note that 1,946 sleeves are equivalent to 60 plugs, or 1.8 percent plugging.

P 1819c/0235c/030885:5 62 3,7l

e

, ) *

• Prairie Island Unit 1 , ,

S/G 1- S/G 2 Maximun number of tubes to be sleeved 1,946 (57 percent) 1,S46 (57 percent)

Equivalent Plugged Tubes 60 (1.8 percent) 60 (1.8 percent)

Existing Plugged Tubes 43 (1.3 percent) 18 (0.5 percent)

Total Equivalent Plugged Tubes 103 (3.1 percent) 78 (2.3 percent) ,

Prairie Island Unit 2 ~

S/G 1 S/G 2 Maximun number of tubes to be sleeved 1,946 (57 percent) 1,946 (57 percent)

Equivalent Plugged Tubes , 60 (1.8 percent) 60 (1.3 percent)

Existing Plugged Tubes 46,(1.4 percent) 95 (2.8 percent) ,

(as ,of October, 1984) 8 Tptal Equivalent Plugged Tubes 106 (3.2 percent) 155 (4.6 percent)

For the steam generators in either of the Prairie Island Units, 5 percent of the total tubes (3388 tubes per S/G) equals 169 tubes plugged in any one steam generator. The ECCS analysis model is such that a unifonn steam generator tube plugging condition is modeled. The NRC staff has required that the LOCA analysis of a plant with steam generator tube plugging model the maximun tube plugging level present in any of the plant steam generators.

For the conditiors presented above for prairie Island 1, the limiting equivalent plugged tube condition in the two steam generators is 103 tubes.

• which provides margin of 66 tubes (169 minus 103) available for additional plugging (or any equivalent combination of sleeves and plugs) before exceeding the basis of the LOCA analysis with 5 percent SGTP. With a smaller number of 1819c/0235c/030885:5 63 3 72

sleeves, the margin of tubes available for additional plugging would be

~

. larger. With only 500 sleeves per steam generator,110 tubes (169 minus 59) would be available for additional plugging.

For Prairie Island Unit 2, the limiting equivalent plugged tube condition th the two steam generators is 155 tubes, which provides margin of 14 tubes (109 minus 155) available for additional plugging (or any equivalent combination of sleeves and plugs) before exceeding )he basis. of the LOCA analysis with 5 percent SGTP. With only 500 sleeves per steam generator, 49 tubes (169 minus .

111) would be available for additional plugging.' Accordingly, no ECCS results

- more adverse than those in the existing Westinghouse fuel safety analysis are anticipated for equivalent tube plugging projected to occur at the Prairie Island Units with up to 1,946 sleeves per steam generator, given that the existing vessel internals remain in place.

The effect of sleeving on the non-LOCA transient analyses has been reviewed.

Analyses of the level of sleeving and plugging discussed in this report have shown that the Reactor Coolant System flow rate will not be less than the Thermal Design Flow rate. The Thermal Design Flow rate is that which is

assumed in the non-LOCA safety analyses and is designed to be less than the minimum RCS flow rate that could occur under normal or degraded condftfons.

i

.Since the reduced RCS flow rate is not less than the assumed flow rate (Thermal Design Flow), the non-LOCA safety analyses are not adversely impacted

~

by Sis anticipated maxinum amount of steam generator tube sleeving (1,946 i sleeved per steam generator). Any smaller number of sleeves would have less of an.effect.. The reduced RCS flow rate is within the bounds of the Safety Analysis Report for non-LOCA transient analyses and causes no safety concerns.

l In addition, as a result of tube plugging arid, sleeving, primary side fluid j velocities in the steam generator tubes will increase. The effect of this velocity increase on the sleeve and tube has been evaluated assuming a conservative limiting condition in which 10 percent of the tubes are plugged.

As a reference, normal flow velocity through a tube is approximately 21.6 ft/sec, for the unplugged condition. With 10 percent of the tubes plugged, the fluid velocity through an unplugged tube is 23.5 f t/sec., and for a tube with a sleeve, the local fluid velocity in the sleeve region is estimated at 31.5 ft/sec. This velocity increase causes no safety concerns.

1819c/0235c/030885:5 64 3-73 L -

) . .

3.5.8 ALTERNATE SLEEVE MATERIALS ..

As was sentioned above in Section 3.4.3, Inconel as a sleeve material is '

covered by the ASME Code Case N-20. The desipi stress intensity value 5, for both materials 1690 and 1600 covered by the Case N-20 is identical (5,=26.6ksi). Therefore, for these materials, Primary Stress Intensity and Maxinum Range of Stress Intensity allowables are similar. Only pressure stresses were considered when calculating Primary Stress Intensity. The i

maxinum Primary Membrane Stress Intensity was (bnd at the analysis section on the straight portion of the tube. Hence, the ratio " Calculated Maximum ~

Primary Membrane Stress Intensity / Allowable Stress Intensity" which was critical for the minimum sleeve thickness of [ ] does not -

depend upon the sleeve material (Inconel 690 or Inconel 600). Thermal stress, and hence maximum range of stress intensity and fatigue usage factor, could depend upon the mechanical properties of the sleeve material. The sedulus of elasticity of Inconel 600 is higher than that of Inconel 690 by about

-7 percent. However, the coefficient of thermal expansion of Inconel 690 is higher than that of Incone'l 600. Past analytical experience indicates that '

the e-mismatch between !690 and 1600 as the sleeve material increase thermal stre,sses. Therefore, the results of the Maximum Range of Stress Intensity and Fatigue Evaluations for the sleeve and tube assembly with I600 as the s,i* eve material are conservative relative to those which would be calculated witi 1600 as a sleeve material.

e 1819c/0235c/030385:5 65 3-74 L_

T;- -

W 3

4.0 PROCESS DESCRIPTION

~

The sleeve installation consists of a series of steps starting with tube end preparation (if required) and progressing through sleeve insertion, hydraulic expansion at both the upper and lower joints hard roll joining of the lower i

. joint, brazing of the upper joint and joint inspection. The sleeving sequence

- is outlined in Table 4.0-1. All .these steps are described in the following g sections. , ,

i 4.1 TU8E PREPARATION

~

There are two steps involved in preparing the steam generator tubes for the sleeving operation. These consist of light rolling (as required) at the tube end and tube honing. ,

4.L1 TU' O ROLLING (CONTINGEhCY)

If gaging or tube inside diameter measurements indicate a need for tube end rolling to provide a uniform tube opening for sleeve insertion, a light mechanical rolling operation will be performed. This is sufficient to prepare the mouth of the tube for sleeve insertion without adversely affecting the

. original tube hard. roll or the tube-to-tubesheet weld. Tube end rolling will be performed only as a contingency.

Testing of similar lower joint configurations in model 27 steam generator

. sleeving programs at a much higher torque showed no effect on th?

tube-to-tubesheet weld. Because the radial forces transmitted to the tube-to-tubesheet weld would b'e much lower for a larger model 51 sleeve than for the above test configuration no effect dn,the weld as 4 result of the light roll is expected. '

1319c/0235c/030885:5 66 4-1 l

s

} .

s TABLE 4.0-1 . . -

.. SLEEVE PROCESS SEQUEICE SLMMARY ~

a,c.e .

w h

g. . .

t 4

t 4

t_ l

-t. .

j. Y 4: . , ,

3 l.

1

• 1 I,

I f '

i' t

L 1

l 1819c/0235c/030885:5 67 4-2 1

I i.

I e

} . .

4.1.2 TUBE HONING ..

The sleeving process includes honing the ID area of tubes to be sleeved to prepare the tube surface for the upper brazed joint and the lower joint by ,

removing loose oxide and foreign material. Honing also reduces the '

radioactive shine from the tube bundle, thus contributing to reducing man-rem exposure. .

g .

• Tube honing may be accomplished by either wet or dry methods. Both processes .

have been shown to provide tube inside disneter surfaces compatible with brazed and mechanical joint installation. The selection of the honing process ,

used is dependent primarily on the installation technique utilized, the scale of the sleeving operation (small scale vs. large scale sleeving), and the customers site specific . technical requirements. Evaluation has denonstrated that neither of these processes resove any significant fraction of the tube wall base material.

4.1.2.1 WET' HONING Tube honing will be performed using a [

3a,c.e A limit switch is included in the system design that will prevent the insertion drive from reversing' direction until the desired length of the tube has been honed.

• A waste handling system may be used to collect the [ ],a,c.e the hone debris, and the oxide removed from the tube 10. [

]C'8 There may also be an inlet to the 1819c/0235c/030885:5 68 4-3

i u

) . . ,

c e .

suction pump which subsequently pumps the debris and water diretetly to the' plant waste disposal system.

4.1.2.2 ORY HONING The dry hone process is similar to the wet hone process with the notable exception that the water jet and the attendant systens needed to handle the affluent are omitted. The dry hone pr9 cess is . typically more applicable to handse (manual) or small scale sleeving operations.

In order to remove loose oxide debris produced by the dry honing operation, the tube interior is swabbed utilizing a fluid (typically deionized water or ~

isopropyl alcohol-) soaked felt pad to an elevation slightly less than the honed length, but above the top of the installed sleeve.

4.1.3 FI8EROPT'IC INSPECTION (CONTINGENCY)

~

As a contingency option to spot check that tube 10 surfaces have been honed, a fiberscope inspection may be performed on some of the tubes to be sleeved.

Tubes to be fiberscope inspected would be selected randomly throughout the actual honing process. This fiberscope inspection w'uld be accompitshed prior

, to sleeve insertion..

• 1

, 4.2 SLEEVE INSEATION AN0 EXPANSION ,

4 . e The process of sleeving the tubes is carried out using remotely operated equipment. . The following paragraphs describe the insertion of the sleeves and mandrels and the hydraulic expansion of the sleeves at both the upper and lower joint locations. '

The Westinghouse supplied sleeves are provided complete with braze ring pre-installed and flux pre-appiled over the brate area.

The sleeves are fabricated under controlled conditions, serialized, machined, cleaned, and inspected. They art typically placed in plastic bags, and packaged in protective styrofoam trays inside wood boxes. f)pon receipt at the 1819c/0235c/030885:5 69

{

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

r site. . the boxed sleeves are moved to a low radiation, controlled ~ region near the steam generator. Here the sealed sleeve box is o'pened and the sleeve removed, inspected and installed on the expansion mandrel. hote that the sleeve packaging specification is extremely stringent and, if ~1 eft unopened, ,

the sleeve package is suitable for long term storage.

• The mandrel is connected to the h.igh pressure fluid source, e.g., Haskel

, Expansion Unit (HEU), via high pressu,re flexible stainless tubing. The delivery system is manipulated to locate the guide tube attached to it near ,

the manway. The mandrel / sleeve assembly *is then inserted into the guide

, tube. After the delivery system positions the sleeve upper end below the tube to be restcred, [

Ja,c.e The delivery system is manipulated to locate the guide. tube near the manway for, mandrel withdrawsl/ inspection and a

loadingI of the next sleeve / mandrel assembly. This process is repeated until

, all sleeves are installed and hydraulically expanded.

o In the event that a sleeve becomes jammed after only partial insertion, contingency methods and tooling are used to vemove the jammed sleeve. The tube will then be dispositioned by way of a non-conformance report after considering the appropriate input.

1319c/0235c/030885:5 70 4-5

y . .

WESTINGHOUSE PROPRIETARY (1 ASS 2 4.3 LOWER JOINT SEAL. ,

At the primary face of the tubesheet, the sleeve is joined to the tube by a '

(

,)a,c.e

) .

• The contact forces between the sleeve aid , tube due to the initial hydraulic ~

expansion are sufficient to keen the sleeve from rotatino during the [

],a,c.e The appropriate extent of (

jac.e

[ '

]a.c.e Thjs process is repeated until all installed sleeve lower ends are [ ]

1819c/023Sc/030885:5 71 4-6

1 4.4 BRAZE JOINT PROCESS ' ,.

a After the sleeves have been [ j ,c.e at

,, the lower sleeve ends, the upper joints are brazed as discussed below. ,

6 4.4.1 BRAZING MATERIAL y The brazing material is a noble metal alloy of [

-].a.c.e A gold-based filler metal was chosen to produce a strong .

. joint with high resistance to corrosion,' good ductility, and compatibility with Inconel 600 or 690 sleeves and the Inconel 600 base material of the tube. .

The liquidus and solidus temperature of the braze are [ ]a,c.e The filler metal is fabricated into a [

ja.c.e 4.4.2 FLUX APPLICATION A flux is applied to the sleeve in the sleeve assembly process. The flux is used as a wetting agent to facilitate braze flow and as a protective

• agent for

'the braze area during the brazing process. The flux used is [

3a,c.e ,

. . 4.4.3 BRAZING OPERATION The brazing operation consists' of the following steps.

1. Insertion The braze heater is inserted into the installed sleeve in the same manner as described for Mandrel / Sleeve Loading with the remote delivery system.

(Reference Section 4.2.) (

1819c/0235c/030885:5 72 4-7

j . .

v ..

. t g . .

-i 4

jac.e 4.5 SLEEVE IN$PECTION .

4.5.1 PROCESS SAMPt.!NG Pt.AN In order'to verify the final sleeve installation, an eddy current inspection will be perfomed on all sleeved tubes to verify that all sleeves received the required hydraulic and roll expansfor.s. The basic process check on 100 percent of the sleeved tubes will be:

1. Verify lower hydraulic

• expansion average diameter

2. Verify lower roll and location within the lower hydraulic expansion and average diameter

3. Verify upper hydraulic expansion average diameter

• 4~8 1819c/0235c/030885:5 73

,c 3

Tubes not satisfying the basic process check criteria will be ,dispositioned on an individual tube basis. -

. In order to monitor the sleeving process after each operation from each lot, eddy current data on a percentage of the sleeves will be performed to obtain, sleeve'10 data. ' As confidence is gained that the sleeving process is proceeding as anticipated, the lot sizes will be increased and percentages reduced. These average diameters will be eval,uated versus the expected tolerances established through the design requirements, laboratory testing results, and previous experience. This evaluation will ~ determine whether or not the equipment / tooling is performing satisfactorily. If process data is determined to be outside of expected ranges, further analysis will be ~

perfonned.

If required, Diatest may be used in lieu of eddy current to perform sleeve

, installation acceptance and in-process monitoring evaluations. Undersized diameters will be corrected by-an additional expansion step to produce the desired degree of expansion. Oversized diameters will be dispositioned by a specific evaluation process on an individual tube basis.

If it is necessary to remove a sleeved tube from service as judged by.an

, evaluation of a spe,ci.fic sleeve / tube configuration, tooling and processes will be available to plug the sleeve or the lower portion of the sleeve will be removed and the tube will be plugged. ,

. -e As mentioned previously, the basic process dimensional verification will be completed and evaluated for 100 percent of all installed sleeves.

. 4.5.2 ULTRASONIC INSPECTION The final stage of the brazing operation is the inspection of the braze joint for continuity. This is performed with an ultrasonic technique described in Section 7.0 of this' report. This inspection is performed to confirm the. ~

l leaktightness and structural integrity of the brazed joint between the sleeve and the steam generator tube.

. l 1819c/0235c/030885:5 74 4,9

j The UT and effector is inserted into the sleeve in .the same manndr'as described for Mandrel / Sleeve Insertion with the delivery system.. (Reference Section 4.2.) The linear translation and rotational motion of the ultrasonic.

' probe is controlled with equipment located in a remote low radiation area.

1 A typical UT trace from a braze joint is shown in Figure 4.5.24.

3 4.6 ESTA8LISMENT OF SLEEVE JOINT MAI,N FA8RICATION PARAMETERS 4.6.1 LOWER JOINT -

t

-The main parameter for fabrication of acceptable lower joints is sleeve [

].ac.e 3),,,,g ga.c.e is a function of the [

]."'C Accordingly, rolling torque was varied to ,

achieve the desired sleeve [ ]C in' the orioinal Model 44 program (also applicable to the model 51). [

,]C was achieved was used throughout the program verification testing.

4.6:2 UPPER, JOINT a

The upper brazed joint parameters were defined by the need to arrive at a leak tight, mechanically acceptable joint. These parameters are divided into-2 areas as follows. .

The utilization of a [- .]C heat source has eliminated bulky-equipment and time consuming complicated control system handling, resulting in higher production efficiency and better braze process control.

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The specific' brazing parameters (heatup, holdtime, etc.) are recorded in the Brazing Process Specification.

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'5.0, SLEEVE / TOOLING POSITIONING TECHNIQUE .

1 5.1 REMOTELY OPERATED SERVICE ARM (ROSA)

ROSA is a general purpose six axes all-electric computer-controlled robot used '

for nuclear service work. Its function is.to serve as a remotely controlled-tool positioner and thereby reduce worker radiation exposure. The major ROSA system components include the mechanical arm with a servo controller and the ,

supervisory computer control console contained within a trailer located

'. outside ~ containment. The operator issues. commands to the supervisory computer through the control console and keyboard. The supervisory computer interprets these commands and calculates the desired angulae positions for each axis of -

' the mechanical am. These desired angular positions are then sent to the servo controller.- The servo controller drives each axis to its desired position, and sends status information back to the supervisory computer. This cycle is continuously ' executed at a high rate of speed, providing smooth and controlled motions. ,

One application of ROSA is its use as a "No Entry" tool positioner for primary si4e steam generator operations. The term "No Entry" signifies that ROSA installation / removal, tool changing, and tool operations are performed without

.any personnel passi,ng through the plane of the manway's outer surface.

ROSA is loaded into the channel head by use of a ramp loading fixture mounted

, to the manway flange. The tool end of ROSA is clamped to this fixture.

, Through a combination of ROSA movements and linear movements of the loading i

fixture, ROSA is loaded into the channel head such that its base end and four hydraulic camlocks end up approximately 2 inches below the tubesheet. From

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there, a joystick controller in the coptrol trailer is used to drive the camlocks up and into the tubes. These camlock' s are then pressurized to 750 psi, generating the necessary frictional holdi.ng force to secure ROSA to the tubesheet. The tool end of ROSA is then unclamped from the loading fixture.

With the base end of ROSA secured to the tubesheet, ROSA is programmed to reach out through the manway such that tools can be manually installed or t ,

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P renoved. ROSA is then progransned to pull the tool in through..the manway 'nd a up to the tubesheet.

• The ROSA computer is initialized with the mounting location of the base (row ,

and column) and with the tool being used. The operator can then enter row and column comunands through a keyboard and ROSA will automatically position the

, tool underneath the desired tube., The tubesheet is divided into regions which i

are used by the computer to generate a tool pa,th from the present location of the tool to its destination tube. Although the computer maintains the tool's ,

row and column position its actual row and column position is still verified everyihour.

Tools which are positioned by ROSA include:

1) Eddy Current Tool

2) -Mechanical Plugging Tool

3) Lower Hardrolling Tool

4) Sleeving Adapter Tool - used for honing, swabbing, fiberscoping, sleeve insertion, expansion, brazing and ,

. ultrasonic testing All these tools are. controlled from inside containment, independently from ROSA. ROSA is prograpuned to move the sTeeving adapter tool to a Iccation over the manway so th4t there is an assembly window above the manway to change out

. the various tools which it can position.

The tools typically have low light level cameras or fiberscopes mounted on l them. These cameras or fibersc' opes are used to help verify exact positioning of the tool under the desired tune, toiveriff that sleeves, hardrollers, braze j heaters, UT probes, etc., 'are fully thserted (contacting the tube end) before initiating their operations and to assist in determining the tooling performance. The three axis joystick controller can be used to make minor position and orientation adjustments of the tool so that it is correctly ~

aligned with the tube.

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5.2, ALTERNATE POSITIONING TECHNIQUES . .

Under some conditions, positioning of sleeves / tooling with the base ROSA robotic system may not be practical. In these circumstances, an alternate

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positioning technique may be utilized. These alternate techniques may include alternate robotic or semi-remotely-operated equipment, hands-on (manual) positioning and instal.lation, or the combination of two or. more tooling subsystems into one larger tooling system. ,

Note that with all positioning techniques, the processes actually used to install the sleeves [

]*'C will not be changed due to the use of an alternate ~

sleeve / tooling positioning technique. It is the processes to which the sleeves are subjected that are critical to their successful installation; the technique used to position the sleeves and tooling is not critical so long as it does not affect the sleeve installation processes.

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, . 6.0 N0E INSPECTABILITY ,,

The N0E development effort has concentrated on two aspects of the brazed sleeve. First, consideration was given to a method of verifying that the upper and lower. joints meet the design requirements. Second, the tube / sleeve assembly must be capable of being evaluated through subsequent routine in-service inspection. In both of these effarts it has been necessary to rely as much as possible on existing technology

• for, the inspection process. The technologies that are being addressed are ultrasonic and eddy current for the routine inspection. .

6.1 ULTRASONIC BRAZE INSPECTION 6.1.1 PRINCIPLE OF OPERATION The ultrasonic inspection of the brazed joint is based on the idea that an acceptable brazed joint will transmit essentially all the ultrasonic energy incident upon it. On the other hand, an inadequate brazed joint will reflect some of the energy incident upon it.

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, f'C An ultrasonic wave is launched by the application of a pulse to a piezoelectric transducer. The wave propagates in the couplant medium (water) un,til it strikes the sleeve. Ultrasonic energy is both

,- transmitted and reflected at the boundary.' The reflected wave returns to the transducer where it is converted back to an electrical signal .which .is

[ amplified and displayed on an oscilloscope. The transmitted wave propagates in the sleeve until it reaches the outside surface of the sleeve. If brazing material is present, the wave propagat$s through the joint into the -tube.

When the wave reaches the outside of the tube 'it is reflected back toward the transducer through the brazed joint to the sleeve-couplant interface. When the ultrasonic wave reaches the sleeve-couplant interface, some energy is transmitted through the interface to the transducer. The transmitted energy

• results in a signal on the oscilloscope screen. The reflected energy continues to propagate in the sleeve assembly losing energy each time it reaches the sleeve-couplant interf ace. The resulting oscilloscope display 1319c/0235c/030885:5 80 6-1 l

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from a sound brazed joint is a large signal, from the sleeve-couplant interface, followed by a decaying series of smaller " echoes" spaced by the time of travel in the sleeve-tube assembly. If there are some void regions in the braze, a complex combination of these two signal patterns wil,1 result.

Thus, by observing the patterns in the reflected pulse and comparing them to

. patterns observed with joints of a known quality, a quality can be assigned to the brazed joint.

- To provide additional resolution, an investigation into the use of (

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.]a.c.e was conducted. The response of the ['

, .]a,c.e in the braze region is shown in Figure 6.1.1-2. The resultant wave form for a good braze is characterized by the ( -

']C'8 These patterns differ from those generated with the (

]C'8 The next result is that the ( *

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, The, conclusion is that an ultrasonic transducer which is [ ]C'8 provides the optimum inspection of the braze. ,

6.1.2 ULTRASONIC Sh5 TEM

, To test,the feasibility and to develop an, inspection procedure, a test bed was constructed. [

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• E00f CURRENT INSPECTIONS The'e(dycurrent'inspectionequipment, techniques,andresultspresented herein apply to the proposed Westinghouse sleeving process for use in steam -

generators which have 0.875" 00 by 0.050' nominal wall. Due to the similarities between the Series 51 and Series 44 stem generator designs and the fact that approximate'ly 6000 sleeves made from thermally treated Inconel 400 with mechanical joints are currently installed in Series 44 steam generators, it is expected that similar addy current inspection results will .

be'obtained with equipment and techniques developed for the Model 51 steam generators. '

l Eddy current-inspections are routinely carried out on the steam genergtors in accordance with the, plant's Technical Specifications. The purpose of these inspections is to detect at an early state tube degradation that may have occurred during plant operation so that corrective action c,an be taken to

, miniette further degradation and reduce th'a potential for significant '

, primary-to-secondary leakage.

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The standard inspection procedure involves the use of a bobbin eddy current probe, with two circeferentially wounq coilh which are displaced axially along the probe body. The coils are sonnected 'in the so-called differential '

mode; that is, the system responds only when there is a difference in the properties of the material surrounding the two coils. The coils are excited

• by using an eddy current instroent that displays changes in the material -

l surrounding the calls by measuring the electrical impedance of the coils. In the past, addy current instruments normally excited the colls at a single '

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.j frequency. However, Westinghouse and the 1,ndustry are now using .

.. multi-frequency instrumentation for the inspection of steam generator tubing.

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This' involves simultaneous excitation of the cells with several different test frequencies.

, The outputs of .the 'various frequencies are , combined and recorded. The condpined data yield an output in which signals resulting from conditions that do not affect the integrity of the' tube are reduced. By reducing unwanted 3 ' signals, improved inspectability of 'th's tubing results (i.e., a higher

= signal-to-noiseratio). Regions. in the steam generator such as the tube suppoets, the tubesheet, and sleeve transition sones are examples of areas '

where citifrequency processing has proven valuebie in providing improved '

inspecteility.

A number of eddy current probes and signal processing systems are available for the eddy current inspection of the tube / sleeve assembly. In addition to the conventional bobbin cott probe, there are a rotating pancake coil and a cross-wound coil probe. Any of these probes may be used with either single '

frequency or altifrequency instrumentation.

After sleeve installation, all sleeved tubes are subjected to a serles,of eddy current inspectionsi .Some of these inspections are part of' a process control procedure to verify correct sleeve installation. However, each tubelsleeve

~ assembly also receives an oddy current inspection for basel,ine purposes to

, 'which all subsegi$pnt inspections will be c'ampared.

< Verific'ation of proper sleeve installation is of critical importance in the sleeving process. An "in-process' eddy current inspection is conducted utilizing one frequency in the esclutg ede mith a conuntional bobbin coil probe. This inspection is performed during slaieving installation to provide "in-process' verification of the existence of proper hydraulic espansion and hard roll configurations and also to allow detemination of the sleeve process diensions ,both axially and radially, using the strip chart recording. -

The inspection for degradation of the tubelsteeve assembly iias typically been .

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) s enc,1tation. For the straight length regions of the tube /sleev,e assembly,' the inspection of the sleeve and tube is consistant with normal tubing inspections. - In tube / sleeve assembly joint regions, data evaluation becomes

' mere complex.- - The results discussed below suggest the limits on,the volume of '

degradation that can be detected in the vicinity of geometry changes. For the parent tube, these limits are on the order.of two to three times the response of the A$M calibration standard using

• the conventional bobbin coil probe.

The detection and quantification of degradation at the transition regions of ,

the sleeve / tube assembly depends upon the. signal-to-noise ratio between the degradation response and the transition response. As a general rule, lower

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frequencies tend to suppress the transition sign 41 relative to the degradation sipal at the expense of the ability to-quantify. Similarly, the inspection of the tube through the sleeve requires the use of low frequencies to achieve detection with si associated loss in quantificaton. Thus, the search for an optism eddy current inspection represents a trade-off between detection and

. quanti fication. With the conventional bobbin type inspection, this optimization . leads to a primary inspection frequency for the sleeve on the

• 4,c.e order of ( ,

and for the tube and transition regions on the order of I 38 '" Figure 6.2.1 shows the response of the ASE tube calibration standard'using a conventional bobbin coll. Figure 6.2.2 shows the response of a typicpl. expansion transition at the same frequencies as Figure 6,2.1 but at a factor of two lower sensitivity for the non-mixed channels. In Figures 6.2.1 and 6.2.2, the results of combining the 50 kHz and 150 kHz

, responses to eliminate the transition signals are depicted. hoto that in the transition regions a signal with twice the amplitude of the standard would be i detectable. However, with present Instraentation the actual noise level from the electronics Ifmits the usefulness of- this approach.

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. For those regtons of the sleeve where*the assembly has no transitions, a conventional bobbin coil inspection provides detection and quantification ,

capability. Figure 6.2.3showsatypical( )*'Cphaseangleversus degradation depth curve for the sleeve from which 00 sleeve penetrations can -

be assessed.

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i In the regions of the parent tube above the sleeve, conventional" bobbin coil j inspections will continue to be used. However, since*the diameter of the  ;

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sleeve is smaller than that of the tube, the fill factor of a probe inserted  !

through the sleeve may result in a decreased detection capability for tubing , , l degradation. hs, it may be necessary to inspect the unsleeved portion of

i. the tulps above the sleeve by inserting a standard sf as probe through the i j U-bend from the unsleeved leg of the tube.

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• While there are a number of probe configurations that tend themselves to . [

improving the inspection of the tube / steeve assembly in the regions of l

, configuration transitions, the cross-wound coil probe has been selected as  !

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! , offering a significant improvement over the conve'ntional bobbin coil probe, '

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yet retaining the simplicity of the inspection procedure.  :

L e i The overall inspection procedure involves the use of the cross-wound probe f

which significantly reduces the responses of the transitions, coupled with a t multifrequency mixing technique for further reduction of the remaining noise i sipals. This system reduces the interference from all discontinuities which have 340-degree symmetry, providing improved visibility for discrete l discontinuities. As is shown in the accompanying figures, in the laboratory  !

this technique can detect 00 tube well penetrations with acceptable * ,

sipal-to-noise ratios at the transitions when the volume of metal removed is  !

l equivalent to the ASME calibration standard.

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The sigdificant reduction of response from the tube / sleeve assembly transitions due to the use of the cross-wound call is shown by a caparison of Pigures 6.2.4, 6.2.5, and 6.2.6 for the sleeve standards, tube standards and t transitions, respectively. Again, this is further improved by the combination i of the various freevi atles. ( i

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)*' Pigure 6.2 7 shows the phase / depth curve for the tube using

, l this combination. As enamoles of the detection capability at the transitions, j Pigures 6.2.8 and 6.2.g show the responses of a 20 percent 00 penetration in l the sleeve and 40 percent 00 penetration in the tube, respectively.

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The, preceding discussion has centered around the inspection,of, the expansion transition regions of the assembly. For inspection of the region at the top end of the sleeve, the transition response using the conventional bobbin inspection is still larger than that of the expansion regions as,shown in Figure 6.2.10. Thus, the signal-to-noise ratios for this part of the '

tube / sleeve assembly is about a factor of four less sensitive than that of the expansions. Some improvment has ,been gained by tapering the wall thickness at the top end of the sleeve. This reduces the end-of-sleeve signal by a i

factor of approximately two. The crosswoundoc'll, however, again significantly reduces the response of the, sleeve end. Figure 6.2.11 shows the response of various ASME tube calibration standards placed at the end of the sleeve using the cross-wound coil and the (, '

la.c.e frequency

• combination. Note that under these conditions, degradation at the top end of the sleeve / tube assembly can be detected.

In the braze region conventional eddy current inspection techniques were evaluated to determine the impact of the braze on the eddy current response of the joint. To begin, the eddy current response of the braze region prior to brazing and the braze region without the braze ring were obtained in Figure 6.2,.12. (

.)b.c.e As ,a result of this, it is a, simple matter to distinguish

, between's braze that has been heated to a point where the braze has flowed and one that has not, allowing for process verification.

r Comparison of Figure 6.2.13 with the eddy current signature of a typical bears t joint with 5/8" sleeves, Figure 6.2.12, reveals that the gross features of the waveforms are similar. To> begin, the braze $lgnature indicates that the braze groove has emotied. In addition, there is a subtle change in the waveform originating fra the second transition zone. This change is most noticeaole in the (' '

b l ,c.e To confirm this, another series of simulations were e

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f, steilled.' These simulations involved inserting rings of brate , material of' various widths and thicknesses inte' the brase region.' Figure 4.2.14. The resultant ( -]b,c.e eddy current signatures are found in Figure ',

I 4.2.15. - Emaninetion of the response of the ( ,]U' ' '

i brase simulation reveals that the response displays the character of the braae  :

j sample of Figure 4.2.14, confirming the speculation that the brane is indeed

. visible to addy current inspectiegs.

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- A further comparison of the response of the various brase widths shows that l thereisa( -

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$ lace the response of the brase is a unique function of the brase flow, each  !

joint has its om ed# cyrrent signature. As a result, an ed$ current base

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line of each joint will be obtained against which all subsequent inspections can be compared. Siptf fcant changes in the ed# current signatures may l laticate degradation within the brase region. '

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r Seth ultrasonic a[nd oddy current techniques have been evaluated for the

. Inc'Ntion of the sleeve assembly. Ultrasonic techniques provide a viable t

, , means pf assessing brase flew and entent. Eddy current techniques will provide a viable means of assessing the sleeve assemely for in-service inspection. '

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s Conventional eddy current techniques have been edified to incorporate the

, most recent technology in the inspection of the sleeve / tube assemoly. The resultant inspection of the sleeve / tube assembly involves the use of both a  !

conventional bothin cell for the straight regions of the slaeve/ tube assemely I and a cross-seend coil for the transition regions. It should be emphastaed [

l that the transition regions of the assembly, where the cross-wound coil and I aultifrequency processing are necessary for degradation detection, comprise

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only a small percentage of the overall sleeve / tube assembly, .Thus the conventional inspection would constitute the bulk of 'the eddy current inspection. l#iile there is a significant improvement in the inspection of portions of the assembly using the cross-wound coll, efforts continue to . ,

advance the state-of-the-art in eddy current inspection techniques. As improved techniques are developed and verified, they will be utilized. For the present, the cross-wound coil, probe represents an inspection technique that provides additional sensitivity ,and suppqrt for, eddy current techniques as a viable means of assessing the tube / sleeve assembly. .

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4 FIGURE 6.1.1 1 Ultrasonic Testing of the Brated Joint -

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E.C. Signals from the ASTM Standard, Machined on the Sleeve O.D. of the SleeveTube Assembly Without Expansion (Cross Wound , Coil Probe)

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Figure 6.2.15.100 kHz Eddy Current Signatures for Various Braze ,

Widths and Brare Thickness 6 34

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Widths and Braze Thickness e

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Figure 6.2.16. Effect on E.C. Braze Response of 1/4" EOM Notch Thru the Tubewall e

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7.0 ALARA CONSIDERATIONS FOR SLEEVING OPERATIONS The repair of steam generators in operating nuclear plants requires the utilization of appropriate dose reduction techniques to keep radiation exposures As low As Reasonably Achievable ( ALARA).. Westinghouse maintains an extensive ALARA program to minimize radiation exposure to personnel. This program includes: design and improvement of remote and semi-remote tooling, including state-of-the-art robotics; decontamination of steam generators; the i

use of shielding to minimize radiation exposure; extensive personnel training utilizing mockwps; time trials; and str.ict qualification. procedures. In addi, tion, computer programs (REMS) exist which can accurately track radiation exposure accumulation. * -

The ALARA aspect of the tool design program is to develop specialized remote tooling to reduce the eItposure that sleeving personnel receive from high radiation fields. A design objective of the remote delivery sleeving system is to eliminate channel head entries and to complete the sleeving project with  !

total exposures kept to'a minimum, i. e., ALARA. The manipulator arm is installed on a fixture attached to the steam generator manway af ter video cameras and temporary nozzle covers have been installed. The control station operator (CS0) then manually operate controls to guide the manipulator arm

, through the menway and attach the baseplate to the tubesheet. The installation of the arm requires only one platform operator to provide visual observation and assistance with cable handling from the platform. The control

, station for the' remote delivery systee.is located outside containment in a '

specially designed control station trailer.

r The control of personnel exposures can also be effected by careful planning, i training, and preparation of maintenagce precedures for the job. This form of administrative control can ensure that the minimum number of personnel will be used to perform the various tasks. Additional methods of minimizing exposure include the use of remote TV and radio surveillance of all platform and channel head operations and the monitoring of personnel exposure to identify

• high exposure areas for timely improvement. Local shielding will be used whenever possible to reduce the general area background radiation levels at o

I ' ,

! 1819cl023Sc/030885:5 91 71 t

g '

• r the work stations inside containment. A combination of these techniques is expected to be used in this steam generator sleeving project.

7.1 ROSA SLEEV!ne OptAAft0k5 The Restely Operated Service Arm (ROSA) is ,a remotely-operated robotic, general purpose tool positioning systen designed for perfoming various ,

maintenance tasks in the steam generator channel head and other radiologically .

I hostile environments. The systen is op'erated re'motely from the control I station located outside containment up to 200 feet from the channel head. The am is designed to accept a faily of end effectors that are used to implement the various processes used in steam generator tube' maintenance. -

7.2 MANIPULATOR EW EFFEC, TOR 5 The ROSA system is designed to assist in performing a wide variety of tasks in ,

the channel head. This is,acc eplished by firstly attaching the appropriate _

i end effector to the arm. The end effectors are designed for specific or multi-purpose use during sleeving operation. Some current applications of  ;

reste anipulators are steam generator eddy current inspection, plug weld

• repair, tube end repair, mechanical plug installation, and tube sleeving f olprations. An and effector is equipped with a standardized quick disconnect V-band coupling for manual attachment to the manipulator from the steam generator platform. The arm is extended through the manway ,and the quick

, disconnect coupling is oriented at right an'gles to the axis of the manway.

This allows the changing of end effectors outside direct shine of the manway radiation beam, minimizing radiation exposure.

7.2.1 SLEEVE / TOOLING EN0 EFFECTOR 5 ,

i The sequence of process steps and associated tooling required to complete a, staan generator tube sleeving project results in many and effector changes. I The sleeving operations of. tube end rolling-(contingency), tube honing.

• fiberscoping (contingency), sleeve / mandrel insertion and expansion, lower hard roll, hrazing,' ultrasonic testing, process verification eddy current [

inspection, and baseline eddy current inspection will require a significant

'319cl0235cl030885:5 92 72 L

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s number of. tool changes during the project The platform operator will be required to change end effectors of increasing compl'exity from fiberscope and' lower hard roller tooling to the more complex brazing and sleeve / mandrel insertion and expansion tooling systems. The number and frequency of changes will depend on the scope of the sleeving project.

7.2.2 IN-PROCESS OPERATIONS ,

The necessity of having a platform operator available near the platform ,

extends into the in-process sleeving operations. The useful life of a hone is expected to be limited to approximately 5-50 tubes (depending on the honing

~

process utilized) before the hone will need to be replaced. The fiberscope inspection seque'nce may require various lengths of fiberscopes to reach all of the tubes during the ingpection. The sleeve / mandrel insertion and expansions operations are expected to require the major part of the in-process time spent on the platform. The removal of spent expansion mandrels and the installation of the new sleeve / mandrel unit may have to be done manually from the platfom. The hard rolling, brazing, ultrasonic testing, and eddy current operations will require truch less time on the platform.

7.3 CONTROL STATION IN CONTAINMENT ,

The process control stations for the various sleeving processes will be-located in containment in a low radiation area near the steam generator

, platforms. These erk stations are required to operate and control the

. individual sleeving processes and are independent of the ROSA systems controls i

located outside containment. The variation in service requirements such as

, air, water, electricity, radwdste generation, and proximity of controls-to-processes makes the in-containment control stations a necessity.

7.4 POTENTIALS FOR WORKER EXPOSURE The continued development of the ROSA sleeving process is expected to

• significantly reduce the radiation exposure to workers in comparison to previous sleeving projects. The elimination of channel head entries for the installation and removal of sleeves and sleeve tooling fixtures will keep o

1319c/0235c/030835:5 93 7-3

3 ,

personnel out of the high radiation fields of the steam generator cha'nnel heads. The mejority of the sleeving operations will be done from the control i

stations with one or two workers stationed on or near the platform. However, in the preparation of the steam generators for sleeving operations, entries into the channel heads may be required. ,

7.4.1 N0ZZLE COVER AND CAMERA INSTALLATION / REMOVAL.

The insts11ation of temporary nozzle co' vers in be reactor coolant pipe

, nozzles in preparation of the steam generators for sleeving operations will require channel head entries. The covers are installed to prevent the accidental dropping of any foreign objects (i.e.. tools, nuts, bolts, debris,

• etc.) into the reactor coolant loops during sleeving operations. In the event that an accident did occur, inspections of the loops would be required and any foreign objects or debris found would have to be retrieved. The impact on schedule and radiation exposures associated with these recovery operations would far exceed the time and exposures (less than 1 minute) expended to install or remove loop nozzle covers. Consequently, it is considered an ALARA-efficient procedure to utilize temporary nozzle covers during sleeving oper,ations. ' '

s The use of video non,itoring systems to observe ROSA operations in the channel head will also require manual installation. The installation of overview cameras to monitor, sleeving operations will require a full or partial channel

, head entry to be installed.

a' The insts11ation and removal of this equipment in the steam generators are the only sche'duled requirements for thannel head entry during the sleeving project.

7.4.2 PLATFORM SETUP /5UPERVISION The sejority of the radiation exposures recorded for the sleeving program is expected to result primarily from personnel working on or near the steam -

generator platforms. The setup and checkout of equipment for the various sleeving processes, the installation / removal of ROSA, the changing of end effectors, and the operation of the sleeve / mandrel insertion and expansion 1819c/0235c/030885:5 94 74 l

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• e q

sy} ten are the major sources of radiation, exposure. In addition to channel head video nonitoring systems, visual nonitoring and* supervision by one or ,

more workers on the platfons will be required for a major part of the sleeving

~

schedule. Experience has shown that rapid response to equipment adjust;nent requirements is efficiently accomplished by having a platform worker standing by in' a relatively low radiation area during . operations. Worker standby stations have ranged from the low radiation fields behind the biological shield to lead blanket shielding' installed on the platform. Even though radiation levels on the platform are*much lower than channel head levels, a substantially larger amount of time will, be spent on the platforms giving rise to personnel exposures. An evaluation of radiation surveys around the steam generators should indicate appropriate standby stations. -

7.5 RA0 WASTE GENERATION The surface preparation of tubes for the installation of sleeves requires that the oxide film be renoved by a honing process. A flexihone attached to a flexible rotating cable will be used to remove the oxide flim on the inside surface of the stesa generator tubes. The volume of solid radwaste is expected to consist of spent hones, flexible honing cables, hone filter assemblies (optional), radioactive water from tube honing, and the norma)

. anti-C consumabl'es, associated with steam generator maintenance. The anti-C contumables are usually the customer's responsibility and will not be ,

ad< ressed in this report. .

Forthe[ ]4.c.e approximately thirty tubes can be honed L r before the hone is changed for process control and [

a

+]..c.e A typical estimate of the radioactive concentration fron a honed tube and transported by the [

ja,b,c.e .

L ~

The flexible honing cable used to rotate the hone inside the tubes is slso

, ( 3a,c.e during the honing process. The construction of the stainless o.

g 1819c/0235c/030885:5 95 i

7-5 l

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y ,

j TA8LE 7.5-1 .

EST! MATE OF RA010 ACTIVE CONCENTRATION IN WATER PER 708E HONE 0 (TYPICAL) 4 Percent Activity

• Inventory ,

!sotope Concentration (sci) . (aci/ccofy0) b,c.e 1 .

e ASSUMPTIONS ,

1) Tube honed 48 inches (in length)

2) Water flow rate of ( ]*'Cpertubehoned l . .

. < 3) Essentially all radioactivity removed from tubes honed.

1819c/0235c/030885:5 96 7-6 L

1 I s steel cable,however, will cause radioactivity to build up ov,er,the course of the project. Radiation levels on segments of the cabfe could [ -

]b,c.e It is expected that an average of one cable per steam generator will be used during the. sleeving ,

project. The cables are consumables and are drummed as solid radwaste, 7.6 A!R80RNE RELEASES .

3 . '

The implementation of the proposed sleeving processes in operating nuclear .

. plants has indicated that the potential for airborne releases is minimal. The major'operationsinclude[ 3ac.e and sleeve installation.

Experience has shown that these sleeving processe's do not contribute to

, . airborne releases.

e 7.7 PERSONNEL EXPOSURE ESTIMATE The total personnel exposures for steam generator sleeving operations will depend on several plant dependant and process related factors. These may include, but not be limited to; the scope of work (quantity of sleeves, etc),

plant radiation levels, ingress / egress to the work stations, equipment

, performance and overall cognizance of ALARA principles. Co,nsequently, the projection of personnel exposures for each specific plant must be performed at the completion of mockup training when process times for each operation have been recorded. The availability of plant f adiation levels and worker process times In the various radiation fields will provide the necessary data to

, project personnel exposure for the sleeving project.

I The calculation of the total MAk4EM exposure for completing a sleeving project may typically be expressed as 6ollowf:

P.Ng.O g+Sg.Ng P . Project total exposure (MAN 4EM) '

Ng = Numcer of sleeves installed 1319c/0235c/030835:5 97 7,7

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j s *

[

j 0, . Exposure / sleeve installed 3, . Equipment setup /reeval exposure per steam generator 4, mueber of steam generators to be sleeved

• i l This equation and appropriate variations are used in estimating the total L

personnel exposures for the sleeving project.

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0 IS19c/0235c/030:45:5 96 78 k -- _ _ _ . _ . - . _ . - _ _ _ _ _ _ _ _ _ _

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s 8.0 INSERVICE INSPECTION PLAN FOR SLEEVE 0 TUBES To address NRC requirements, the operating plant must perform periodic inspections of the supplemented pressure boundary. This new pres,sure boundary consists of the sleeve with a joint at the primary face of the tubesheet and a '

joint at the opposite end of the sleeve.

I The inservice inspection program will , consist qf the following. F.ach sleeved tube will be eddy current inspected on canpletion of installation to obtain a baseline signature to which all subsequent inspections will be compared.

Periodic inspections to monitor sleeve wall conditions will be performed in accordance with the inspection section of the plant Technical Specifications.

• This inspection will be performed with multi-frequency eddy current equipment. The plugging , criterion for the sleeves is established in Section 3.0 of this report.

As part of the inspection,0f the sleeved tubes, there will be a series of pressure / leakage tests. These tests are intended to test the integrity of the mechanical and brazed joint against leakage at both primary and secondary pressure loadings. The tests will be conducted at the conclusion of the sleeving operation and will be performed by the owner in accordance with Applicable requirene,nts of the ASME Code and plant procedures. Periodic pressure testing of the sleeved tubes will also be performed in accordance with the plant Teghnical Specifications. ,

r i

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1819c/0235c/030885:5 99 81

3 1432(8402)/js-1 s CEN-294-NP

, NORTHERN STATES POWER C0!!PANY '

PMIRIE ISLAND NUCLEAR.GENEMTING PLANT ,

LICENSE AMENDMENT REQUEST DATED MAY 17, 1985 l

EXHIBIT E , ,

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, . e t

i COMBUSTION ENGINEERING, INC.

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i i '

January 15,1985 l .

. Prairie Is1.and a

, Steam Generator Tube Repair Usino t.eak Tioht Sleeves i

FINAL R'EPORT Combustion Engineering, Inc.

Nuclear Power Systems Windsor, Connecticut o l F

. 1 g . .

s 3 . LIGAL,NCTICE ,

THIS MEPORT WAS MIEPARED As AN ACCOUNT CP WCMK SPCNSCRED BY CCASUSTION ENetNSERING, INC. NEITHER CCMSUSTION ENCINEERING NCR ANY PERSON ACTING CN IT3 BEHALP: ,

A. MARIE ANY WARRANTY OR MEPRESSNTATICN, EXPRSES CR lt9USD INCLUDING THE WARRANTIES CF MTN838 PCR A PARTICULAR PuRPCas OR MERCH4NTAS8WTY, WITH RESPECT TO THE ACCURACY, COMPLETENSES, OR USSFULNESS CP THE INPCMMATICN CCNTAINED IN THIS REPORT, OR THAT THE UBE OF ANY INPCRMATION, APPARATUS. METHCC, OR PROCIB8 CISCLOSED IN THIS MEPCRT MAY NOT INFRINGE PRIVATILY CWNSD Ml4HT3;OR B. ANUMES ANY UASILITIES WITH RESPECT TO THE 128 07, CR PCM CAMA 488 MESULTING PROM THE UBE OP, ANY INPCMMATICN, APPARATUS, METNCC CM PROC 335 0888*t a2 sri IN THIS MEPORT.

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ABSTRACT * , ..

A technique is presented for repairing degraded steam generator tubes in pressuri:ed water reactor Nuclear Steam Sucolv Systems (NSSS). The technique described alleviates the need for plugging steam generator tubes Whien have -

beceme corroded or are othenvise considered to have lost structural capability. The technique consists of installing a thermally treated Inconel 690 sleeve which spans the section of original steam generster tube which requires recair, and welding the sleeve to the tube near each end of the sleeve.

g . '

• This report details analyses and testing performed to verify the adecuacy of .

repair sleeves for installation in a nuclear steam generator tube. These verific,ations shcw tube sleeving to be an accootable repair technique.

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3-1432(8402)/js-3 T4BLE OF CONTENTS -

Section . Title Pjg, i

1.0 INTRODUCTION

1-1 1.1 PURP0$t -

1-1 i

- 1.2 '

SACXGROUND 1-1 2.0 $UMMARY AND CONCLU5!0N$ 21 '

3.0 ACCEPTANCE CRITERIA 3-1 4.0 Ot3MGM Ot3CRIPTION OF SLEEVE 3. Pt.UG3 AMO. INSTALLATION . ,

wv . man r 4-1.

! 4.1 $LIEVE Ot3!GN Ot3CRIPTION 4-1 ,

4.2 SLEEVE MATERIAL SELECTION 4-1 4.2.1 General Corrosion and Corrosion Product Release Rates 4-1 e

4.2.2 Stress Corrosion'Crackino Resistance 4-2 4.2.3 Coordinated Phosohete Chemistry 4-2

4. 2. 4' Faulted Phosohate Chemistry Control 4-3 4.3 $titVE-TU8t ASSEMSLY

• 4-3 4.4 Pt.UG Ot3!GN Ot3CRIPTION 4-4, 4.5 W .

4-4

.- . ELDED PtuG A55tM8LY .

, 4.6 SLIEVE INSTALLATION (QUIPMENT 4-5 4.6.1 Remote Controlled Maniculator 4-5 4.6.2 Manipulator Elevator .

4-6 i

~4.6.3 Tube Brushino - Cleanins hutament '

4-6 i 4.6.4 Tube Site folling hufement 4-6 4.6.5 $1eeve installation Ecutoment 4-6

. i 4.6.6 $1eeve !.teansion hufement 4-7 4.6.7 Sleeve Welding huf: ment 47 s

4.6.3 %ndestructive Examination 4-4 i I

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1432(8402)/js 4 3 '.

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TABLEOFCONTE$TS(Continued)

)

Section Title '

Pace' 4.7 PLUG INSTALLATION EQUIPMENT 4-8 4.7.1 Remote controlled Elevator 4-8

~

'4.7.2 Sleeve Size Rolling Ecuf erftent

4. .

1 4-8 S

-4.7.3 Plue Installation Ecuicment 4-9 *

, '[

4.7.4 Plug Weldine Ecuicment

.. 4-9

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- +, .-

. . . . _ -. 4.7.5 Nondest'uctive Ecuicment *

. .= 4-9 ... e ..-.

4.8 ALARACONSIDERATIONS) .

.4-9~ . , .

..r

4.9 REFERENCES

TO SEETION 4.0 4-10 5.0 SLEEVE EXAMINATION PROGRAM h' 5 5.1 ULTRASONIC INSPECTION ( 8 5-1 5.1.1' Sumary and ConcTusions -

5-1

- 5.1.2,- UltrasonidsEvaluation 5-1 5.1.3 Test Ecuiement . S' 2 .

5. L4 Defect Samoles 5-3 s

5.1.5 Detailed Results , 5-3

• 5.2 'ED0Y CURRENT INSPECTION 5-5

,' 5.2.1 Sumary and Conclusions 5-5 532 Multi-Frecuency Eddy Ctrrrent- Ecuiement Recuirements 5-5 w

n 5.2.3 Defect Samoles *

, 5-5 5.2.2 Results and conclusions 5-6 5.3 < VISUAL'INSPECTIOb 5-7 5.3.1 Sumarv and conclusion i 5-7

~

5.3.2 Lower Weld Evaluation' 5-7 5.3.3 Uccer Wefd namination 5-8

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~ 1432(8402)/js-5 I l'

TABLE OF CONTENTS (Continued)* I Section Title Pace 5.3.4 Test Ecuiement 5-9 '

5.3.5 Defect Standards .

5-9 6.0 SLEEVE-TUBE CORROSION TEST PROGRAM 6-1 6.1

SUMMARY

AND CONCLUSIONS 6-1 6.2 TEST DESCRIPTION AND RESULTS -

6-1 6.2.1 Modified Huey Tests , 6-1 .

a, 6.2.2 Caosule Tests 6-3 6.2.3 Pure Water Stress Corrosion Tests 6-4 6.2.4 Sodium Hydroxide Fault Autoclave Tests 6-5

6.3 REFERENCES

FOR SECTION 6.0 6-6 7.0 MECHANICAL TESTS OF. SLEEVED AND PLUGGED STEAM GENERATOR TUBE 5 7-1 7.1 -

SUMMARY

AND CONCLUSIONS 7-1 7.2 CONDITIONS TESTED' -

I-1

. 7.3 WELDED SLEEVE TEST PARAMETERS AND RESULTS 7-1 7.3.1 Axial Pull Tests ,

7-1 7.3.2 Lead Cyclino Tests 7-2

/

7.3.3 Collaose Testina 7-2 7.3.4 Burst Testino 7-3 i

7.2 WELDED PLUG TEST PARAMETERS AND RESUL75 74 7.4.1 Weld Intecrity 74

-7.4.2 Axial Lead Caoability 74

~

8.0 -STRUCTURAL ANALYSIS OF SLEEVE-7USE ASSEMBLY 8-1 s -8.1

SUMMARY

AND CONCLUSIONS - 8-1 8.1.1 Cesien Sizine 1-I i

(

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3 A

1432(8402)/,1s-6 TABLE OF CONTENTS (Continued) * .

=Section Title Pace-8.1.2 ~ Detailed Analysis Sumarv 8-1

• 8.2 LOADINGS CONSIDERED 8-5 8.2.1 Uocer Tube Weld Pull-Out Lead 8-5 8.2.2 Lower Stub Weld Push-Out load' 8-5 8.2.3' Weld Faticue -

8-6 8.3 REGULATORY GUIDE 1.121 EVALUATION FOR Alt.0WABLE 8-6 ~

SLEEVE WALL DEGRADATION 8.3.1 Nonnal Oceration Safety Marcins 8-7-~ -~

8.3.2 PostulatedPioekuotureAccidents 8-8 '

~-

8.4 -EFFECTS OF TU8E LOCX-UP ON SLEEVE LOADING 8-9 8.4.1 Sleeved Tube in Central Bundle Recion 8-9 Free at Tuoe succort Plates 8.4.2 Sleeved Tube Near Bundle Pericherv 8-14 Free at Tuoe Sucoort Plates 8.4.3 Sleeved Tube in Central Bundle Recion -

Locx-uo at towest succort Piate 8-15 8.4.4 Sleeved Tube Near Bundle Perioherv, Lock 8-15A at Lowest Succort Plate ,

8.4.5 Effect of Tube Prestress Prior to Sleevino 8-16 8.4.6 Lower Stub Weld Pushout Due to Restrained 8-16 rnermai Excansion ,

8.5 SLEEVEDTUBEVISRATIONCONSIDqRATI0t&S 8-16 8.5.1 Effects of Increased Stiffnes's 8-16

-8.5.2 Effect of Severed Tube 8-17 8.6 -STRUCTURAL ANALYSIS FOR NORMAL OPERATION 5-18 -

8.5.1 Faticue Evaluation of Uccer Sleeve-Tut:e Weld 8-19 8.5.2 Faticue Evaluation of Lower Stub Weld 8-21 e -8.7 SLEEVE /TUSE PLUG WELD FATIGUE EVALUAT!0?! 8-23

8.8 REFERENCES

FOR SECTION 8.0 8-25 J

A 1432(8402)/js-7 TABLE OF CON *ENTS (Continued)

• Section Title Pace 8A FATIGUE EVALUATION OF UPPER TUBE / SLEEVE WELD SA-1

' ~

88- FATIGUE EVALUATION OF LOWER STUS WELD 88-1 8C FATIGUE EVALUATION OF TUBE SLEEVE FLUG WELD 8C-1 9.0 SLEEVE INSTALLATION Po,0 CESS '/ERIFICATION 9-1 9.1 WELD INTEGRITY 9-1 9.2 SLEEVE INSTALLATION IN RINGHALS 2 ,

9-2 .

10.0 EFFECT OF SLEEVING ON OPERATION 10-1

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1432(8402)/js-8 LIST OF TABLES -I TABLE NO. TABLE PAGE 3-1 ' REPAIR SLEUING CRITERIA 3-2 3-2 WELDED PLUG CRITERIA 3-4 6-1 STEAM GENERATOR TUBE' SLED E CORROSION TEST 6-2 6 STEAM GENERATOR TUBE SLEDE CAPS LE TESTS 6-4 7 SLEEVE-TUBE ASSEMBLY MECHANICAL TESTING RESULTS 7-5 8-1 ANALYSIS RESULTS

SUMMARY

TABLE , 8-3 .

8-2A AXIAL MEMBER PHYSICAL PROPERTIES 8-10

. . . ~ . . . _ _ _ . . . . . .

8-29 AXIAL MEMBER PHYSICAL PROPERTIES 8-11 8-3 AXIAL LOADS IN SLEEVE WITH TUBE NOT LOCXED 8-12 INTO SUPPORT PLATE 84 AXIAL LOADS'IN SLEEVE WITH TUBE LOCKED INTO 8-13 SUPPORT PLATE -

8-5 UPPER SLEEVE WELO-TRANSIENTS CONSIDERED 8-20

. 8-6 LOWER STUB WELD-TRANSIENTS CONSIDERED 8-22 -

S-7 SLEEVED TUBE PLUG WELO-TRANSIENTS CONSIDERED 8-24 9

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1432(8402)/js-9 LIST OF FIGURES -

FIGURE NO. TITLE -PAGE 4-l ' STEAM GENERATOR TUBE SLEE'/E 4-11 4-2 SLEEVE INSTALLATION 4-12 3 ' STEAM GENERATOR TUBE

• PLUG 4-13 4-4 PLUG INSTALLATION 4-14 4-5 MANIPULATOR ELEVATOR 4-15 4-6 TUBE BRUSHING AND CLEANING TOOL , 4-16 .

'4-7 TUBE ROLLING TOOL 4-17 4-8 SLEEVE INSTALLATION TOOL 4-18 4-9 HYORAULIC EXPANSION TOOL 4-19

~4-10 ELASTOMER EXPANSION TOOL 4-20

'4-11 SLEEVE WELDING HEAD ASSEMBLY 4-21 4-12 SLEEVE WELDING HEAD PCWER UNIT 4-22 4-13 PLUG WELDING TOOL 4-23 4-14 PLUG WELDING TOOL POWER UNIT 4-24 5 'UT TRACE SHOWittG ACCEPTABLE WELD 5-10

. 5-2 '

UT TRACE SHOWING WELD WITH LACX OF FUSION 5-10 4 5-3 CALIBRATION FLAT BOTTCM ORILLED HOLES 5-11 5-4 FLAT BOTTOM ORILLED HOLE STANDARDS 5-12 5-5 CALIBRATION MILLED NOTCH 55 STANDARD 5-13 5-6 MILLED SLOT STANDARD 5-14 5 ACCEPTABLE WELD 5-15 5-8 WELO WITH LACX OF FUSION 5-16 *

'5-9 WELD WITH LACX OF FUSION (SECONO WELO) 5-17 1

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A 1432(8402)/js-10

~

LIST OF FIGURES (Continued)

. . FIGURE NO. TITLE PAGE 5-10 DUAL CROSSWOUND PROBE EDDY CURRENT FIELO 5-18 5 ED0Y CURRENT TEST FLAWS-SLEEVE AND TUBE FLAW 5-19 5-12. TU8E INSPECTION CURRENT TEST SIGNALS-SLEEVE END 5-20

) -WITHOUT AND WITH A TUBE FLAW

~

5-13 TUBE INSPECTION CURRENT TEST. SIGNALS-EXPANSION AND 5-21 WELO WITHOUT AND WITH A TU8E FLAW 5-14 SLEEVE INSPECTION ED0Y CURRENT TEST' SIGNALS- 5-22 SLEEVE FLAWS, EXPANSION AND WELO 5-15 SLEEVE INSPECTION ED0Y CURRENT TEST SIGNALS- 5-23 -

SLEEVE FLAW $ AT EXPANSION TRANSITION 6-1 CAUSTIC STRESS CORROSION AUTOCLAVE TEST SPECIMEN 5-7 8-1A WELDED SLEEVE / TUBE ASSEMBLY IN CENTRAL BUNDLE REGION 8-26 8-18 WELDED SLEEVE /TU8E ASSEMBLY NEAR SUNOLE PERIPHERY 8-27 8-2 LOWER JOINT ROLL OVER 8-28 8-3A SYSTEM SCHEMATIC IN CENTRAL BUNDLE REGION . 8'-29 .

8-38 SYSTEM' SCHEMATIC NEAR SUNOLE PERIPHERY 8-30 8-4 M00(L OF SLEEVE AND LOWER TU,BE . 8-31

• ~

8-5 MODEL OF UPPER WELD 8-32

.,' 8-6 FINITE ELEMENT MODEL OF UPPER TU8E WELD 8-33 8-7 FINITE ELEMENT MODEL OF LO'aER STU8 WELD 8-34 8-6 FINITE ELEMENT MODEL OF SLEEVED *TU8E PLUG WELD 8-35 8-9 TUBESHEET PERFORATED PLATE LIGAMENT STRESSES 3-36 8A-1 UPPER SLEEVE /TU8E WELD ANALYSIS (1) 8A-2 6

k

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s 1432(8402)/js-11 LIST OF FIGURES (Continued) -

FIGURE NO. i tTLE PAGE 8A-2 . UPPER SLEEVE / TUBE WELD ANALYSIS (2) 8A-3 8A-3 N00E AND ELEMENT IDENTIFICATION AND SECTIONS 8A-4 0F INTEREST 8A-4 N00AL AND ELEMENT STRESSES AT SECTIONS OF 8A-5 4'

• INTEREST 8A-5 STRESS RESULTS SECTION 1 THROUGH WELD 8A-6 8A-6 ' STRESS RESULTS SECTIONS 2 AND 3 , 8A-7 .

88-1 SLEEVE /TUBESTUSWELD(HOT.STAN08Y) 88-3

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88-2 SLEEVE / TUBE, STUB WELD (FULL POWER) 88-4

.88-3 SLEEVE /TU8E STU8 WELD (REACTOR TRIP) 88-5

88-4 SLEEVE / TUBE STUB WELD (SEC. LEAK TEST) 88-6 88-5 LOWER TUBE / SLEEVE WELD ANALYSIS 88-7 8C-1 SLEEVED TU8E PLUG WELO (FULL POWER) 8C-2 8C-2 SLEEVED TUBE PLUG WELD (SEC. LEAK TEST) 8C-3 -

8C-3 SLEEVE 0' TUBE PLUG ANALYSIS SC-4 9-1 RINGHALS 2 - DEMONSTRATION - TYPICAL GOOD WELD 94

, 9-2 '

RINGHALS 2 - DEMONSTRATION.- WELD WITH LACX OF 9-5 FUSION ACROSS THE WELO 5

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s 1432(8402)/js-12 LIST OF APPEN0 ICES g . .

APPEN0!X NO. -

NO. OF PAGES A PROCESS AND WELD OPERATOR OUALIFICATION ,

A.1 SLEEVE WELDING AND SLEF/E WELDER 1

! QUALIFICATION

-A.2 REFERENCES 0 APPENDIX A 1

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1.0 INTRODUCTION

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1.1 PURPOSE

The purpose of this report is to provide information sufficient to support a technical specificati.on change allowing installation of steam generator repair sleeves. in the prairie

'C_ _ Island plants. Although a large scale sleeving operation in the

- Prairie Island steam generators is not anticipated, support for 7- reactor operation with up to two thoudand sleeved tubes in each-steam generator is provided. This report demonstrates that .

reactor operation with sleeves installed in the steam generator tubes will not increase the probability or consequence of an

'~ accident previously evaluated. Also it will not e nate the possibility of a new or different kind of' accident and will not*~

reduce the existing margin of safety.

Combustion Engineering (C-E) provides a leak tight-sleeve which is welded to the steam generator tube near each end of the sleeve. The sleeve spans the degraded area of the parent steam generator in the tube sheet region. The steam generator tube with the welded sleeve installed meets the structural requirements of tubes which are not degraded. Design criteria for welded sleeves were precared to ensure that all. design and licensing requirements are considend.

Extensive analyses and testing have been performed to demonstrate

, - that the design criteria are met.

The effect of sleeve installation on steam generator heat renioval .

. capability ,and system flow rate are discussed in this report. Heat removal capability and system flow rate are considered for installa-tion of up to two thousand sleeves in each steam generator.

.After sleeves are installed and i'nspected, a basel'ine examination is performed using eddy current (ET) techniques. The ET examination

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, serves-as baseline to determine if there is sleeve degradation in

, later ' operating years. The ET examination and criteria for plugging sleeved generator tubes if there is unacceptable degradation are described in this report.

P'ugs will be installed if stehve in'sta11ation is not successful or if there is unacceptable degesdation of sleeves or sleeved steam .

generator tubes. Analyses and testing are described wnich comon-strate.that the welded plug design which is provided by C-E is leak tight and will meet structural requirements during normal and postulated accident conditions. .

1.2 SACXGROUND 4

The operation of pressuri:ed Water Reactor (PWR) steam generstors has in some instances, resulted in localized corrosive attack on the

, inside (primary side) or outside (secondary side) of the steam 1-1

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<< 1432(8402)/js-1A 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 g requirements. Thus it has not been necessary to take corrective action unless structural limits are being approached.

Historically, the corrective action taken where steam cenerator tuce 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~peasurement uncertainty.

Installation of steam generator tube plugs removes the heat transfer surface of the plugged tube from service and leads to a reduction in the primary coolant flow rate available for core cooling. Insta11a-

- tion of welded steam generator sleeves does not significantly adfect the heat transfer removal capability of the tube being sleeved and a -

large number of sleeves can be installed without significantly affecting primary flow rate.

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SUMMARY

Atl0 CONC!.USI0rls

• The sleeve design, materials, and joints were designed to the applicable ASME Soiler and Pressure Vessel Code. An extensive ,

analysis and test program was undertaken to prove the adequacy of the welded sleeve. This program determined the effect of normal

' operating and postulated accioent conditions on the sleeve-tube assembly, as well as the adequacy of the assembly to perfonn its intended function. Design criteria were established prior to g performing the analysis and test program which, if met, would prove that the welded sleeve is an acceotable repair technioue. Based upon the results of the analytical and test program described in

• this report the welded sleeve ful' fills its intended function as a leak tight structural member and meets or exceeds all the established design criteria. . -

No detrimental effects on the sleeve-tube assembly are predicted to result from reactor system flow, coolant chemistries, or thermal 'and -

pressure conditions. Structural analyses of the sleeve-tube assembly have established its integrity under normal and accident conditions. The structural analyses have been performed on thirty-six inch long sleeves but twenty-four inch long sleeves will also be installed in Prairie Island. Discussion of why the analyses of thirty-six inch long sleeves are conservative for shorter sleeves is given in Section 8.1.

Mechanical testing has been performed to support the analyses and ASME code stress allowables have been used. Corrosion testin typical sleeve-tube assemblies have been completed and revealgnoof ,

• evidence of sleeve or tube corrosion considered detrimental under anticipated' service conditions.

Welding development has been performed en clean tubing and dirty tubing which has been taken from pot boiler tests 'and simulate

' operation in a steam generator. C-E successfully installed eighteen

, welded sleeves in a sleeve installation demonstration in Ringhals-2 steam generators in May, 1984 The sleeve installation demonstration and a demonstration shcwing that welded sleeves can be successfully inscected.using visual examination or ultrasonic testing (UT) teenniques are described in this report.

i Welded olugs have been develeced for sleeved steam generator tubes in the event that sleeve installation is not successful. No detri-mental effects resulted from suojecting plug-sleeve-tube assemoifes to pressure conditions or mechanical tests. Structural analyses of the installed plugs have demonstrated their integrity under the normal operating conditions cr accident conditions.

• In conclusicn, steam generator tuce recair by installation of welded sleeves is established as an acceptable metnod. #ecair of sleeved steam generator tubes using welded slugs is also establisned as an acceptable method.

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1432(8402)/js-17 l l

3.0 ACCEPTANCE CRITERIA

• The objectives of installing sleeves in steam generator tubes are twofold. The sleeve must maintain structural integrity of the steam generator tube during normal, and postulated accident conditions.

• Additionally, the sleeve must prevent leakage in the event of a through hole in the wall of the steam generator tube. Numerous tests and analyses.were performed to demonstrate the capability of the sleeves to perform these functions under normal operating and i

postulated service conditions. Design and operating conditions for

.the Prairie Island steam generators are defined as:

Primary Side: 590*F (hot side) 2235 psig (ocerating)

, 650*F (design)

Secondary Side: 547'F 2485 psig operatin 735 psig ((design) 600*F (design) , 1085 psig (design) g) ,

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 recort describing tests or analyses which verify the characteristics for a particular criterion is referenced in the table.

Plugs are installed in the sleeved steam generator tubes when the tubes cannot be successfully repaired with sleeves. The objective of the plugging is to prevent leakage between the primary and secondary sides of the staam generator during normal and postulated accident conditions. . .

Table 3-2 provides a summary of the criteria for welded plugs. The format in Table 3-2 is the same as Table 3-1.

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-4.0 DESIGN DESCRIPTI* 0F SLEEVES, PLUGS AND INS 8LLATION EQUIPwENT

• L 4.1= SLEEVE DESIGN DESCRIPTION i'

The sleeve is shown in Figure 4-1. Thesleev_eis'36 inch,esin

• length and has a nominal outsi,de diameter of( J. Sleeve-wall thickness is{ j The sleeve material is thermally-treated Inconel 690. ,

g As shown in Figure 4-1 the sleeve is chamfered at the upper end to

- prevent hang-up with equipment which it used to install or inspect

'the sleeve (or steam generator tu,be). [ .

The outside diameter of the sleeve was selected to provida a gener-ous clerance between the sleeve and steam generator tube so that the sleeve slides freely through the tube "during instalfation. There were two considerations in selecting the sleeve thickness: first, the sleeve has sufficient thickness so that the steam generator tube with the sleeve bridging the corroded section of the tube meets the structural requirements of the undamaged steam generator tube (without benefit from the tube). Second, there is a large margin ~ fn thickness over what is required structurally to allow for sleeve eddy current measurement uncertainty. The inside diameter of the sleeve is large enough so that the flow rste and

. heat transfer capability of the steam generator tube are not signif-icantly affected by sleeve installation. *

• 4.2 SLEEVE MATEA!AL $ ELECTION The tubing from which the sleeves.are fabricated fs procured to ASME

' Boiler and Pressure Vessel Code Case N-20. In addition a thermal

, treatment of 7a0*C is also.specified in order to imoart greater corrosion resistance and lower the residual stress level in the tube.

The primary selection criterion for the' sleeve material was its corrosion resistance in primary and fault secondary PWR environ-ments. Soecific resistance to pure water and caustic stress corro-sion cracking were considered..

C-E's justification for selection of this material is based on the following information:

4.2.1 General Corrosion and Cor*osion Produce Releste ea tes Information published by INC0 (Reference 1) indicates that the corrosion product release rate of Alloy 690 is superior to Alloy 600

in both high temperature amoniated and borated waters. The s

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1432(8402)/js-23 corrosion rate of A11oy.600 is significantly' higher, especially in *

. borated waters, with the concurrent formation of thicker oxides.

The -latter is a potential concern during thermal transients which could initiate crud bursts.

4.2.2 Stress Corrosion Crackino Resistance ,

Alloy 600 in a variety of thermal treatments exhibits kncwn susceptibility to intergranular stress corrosion cracking (IG3CC) in

' high temperature pure water splutions. .Deserated boric acid at high temperature is relatively undisassociated and thus the  !

, resistance-susceptibility of Alloy 600 to IGSCC is comparable. -

Recent investigations (Reference 2) have shown that pure water IGSCC  :

, resistance of Alloy 600 can be improved via controlled thermal-mechanical processing. . .

Laboratory testing on Alloy 690 (References 1 and 3) tubing show it to be fusuune to high temperature deaerated pure H,0 !G3CC in a -

variety of thermst-mechanical conditions. Apparently resistance to -

stress corrosion cracking (SCC) in Alloy 690 is the result of a

, compositional improvement rather than a specific microstructure thus making it more attractive for a welded sleeve design.

Tests. in pure water environments with oxygen present at elevated - ,

temperatures resulted in IG3CC of 304 stainless steel, A11ov 600, and Alloy 800 within a stressed crevice region (Reference 1). Alloy

' 690 in a variety of metallurgical conditions exhibited complete

'* immunity to SCC in this test program with exposure times of 48 weeks. For comparison, the former materials exhibited evidence of IG3CC corrosion after two weeks exposure. *

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4.2.3 ~ Coordinated Phosphate Chemistry i An extensive laboratory test program utilizing hi

, . and model boiler facilities was performed by C-E gh temocrature In the early pot ,

' 1970's. The results of these heat transfer tests indicated that s

phosphate chemicals concentrated in areas of steam blanketing and i

produced thinning of the Alloy 600 heat transfer tubing. This -

phenomena was. observed.over a wide range of sodium to phosphate -

ratios with and without feedtrain corrosion product additions. The consisted of a green nickel-rich corrosion pnosphate comocund product containing, in all cases, lesser amounts of iron and enromium. .

In this program Alloy 800 and 20a stainless steel tubing were also tested and detemined to be more resistant to anosonate wastage. A general correlation between corrosion rate and the nickel content of the transfer tube alloy was observed.

Although the corrosion resistance of Alloy 690 in coordinated onosonate solutions has not been extensively tasted at C-E, based en the observed correlation between corrosion rate and nickel ,

, concentrations, its perfomance should be better than Alloy 600.

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--_m. _ _ _ _ _ . _ _ _ _ _ _ _ _ . _ ___.____________._._______.______________-___.__._._______________..-_____.___._______._._.____..-..-______.______________m_

l'37.ii C )/;s-24 s 4.2.4' Faulted Phoschate Chemistry Control .

If condenser leakage occurs it is possible to alter the sodium to phosphate ratio of the conrdinated phoschate solution such that caustic conditions result in the boiler water. Under these +

conditions, caustic induced SCC may occur. While none of the presently used heat transfer tubi.ng alloys are totally resistant to this form of corrosion attack, mill annealed Alloy 690 shows equivalent resistance to. mill annealed Alloy 600 in concentrated i

solutions (Reference 3). ThermallygreatedAlloy690 exhibited notable improvement in this stress corrosion test as compared with

- mill annealed Alloy 690 and a slight improvement as compared with .

thermally treated Alloy 600.

Similarly, acid forming impurities spec of condenser leakage may concentrate in,ies introduced low flow astothe result regions aggressive levels. Chlorides have been shown to readil

of austenitic stainless steels and fron base allows, e.y produce SCC

g. Alloy-800 -

underthesecon(itions. Immunity to chloride induced SCC was a primary criteria for the switch to nickel-base (Alloy 600) tubing for nuclear steam generating units. Laboratory tests indicate that Alloy 690 also exhibits immunity to chloride induced SCC probably due to its intermediate nickel concentrations (Reference 1).

Recent information obtained via cooperative test programs with the Electric Power Research Institute has identified acid sulfur species as aggressive impurities leading to accelerated corrosion of Alloy 600 steam generator tubing. The modes of attack observed with different sulfur species and concentrations consist of wastage,

• intergranularattack(IGA)andIGSCC. The latter* produced primary to secondary leakage of Alloy 600 tubing representative of all comercial heat treatments, i.e. mill annealed, sensitized, thermally treated. The environment consisted of volatile chemistry control faulted with acidified (H SO fresh water impurities.

' Alloy 690(millannealed) tubing 3xp8s)edtothisenvironmentror longer test periods did not exhibit through-wall !GSCC.

4.3 SLEEVE-TUBE ASSEMBLY The installed sleeve is shown in Figure 4-2. Since the sleeve is 36 inches long, the upper end ofithe slepve is about 15 inches above the supporttoo of the ubesheet and*about 31 inches below the first tube plate.

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The weld and welding operators have been cualified for making upper and lower welds and the weld qualification documents are given in Appendix A. Sin'ce the upper weld is repaired by making a second weld which is centered two inches below the first weld and is made using the same welding parameters, a cualification document for repair is not required.

4.4 PLUG OESIGN DESCRIPTION

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g The weld and weld operstar cualification document for installing plugs in sleeved steam generator tuces is given in Accendix A.

4.6 $ LEE'/E INSTALLATION EQUIPMENT The equipment used for remote installation of sleeves in a steam -

generator is made up of the following basic systems. These systems are:

1. Remote Controlled Manipulator

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8. Nondestructive Examination Equipment .

. 'These systems, when used together, allow installation of the sleeves

, without entering the steam generater. In this way, personnel exposure to radiation is held to a minimum.

4.6.1 Remote Centro 11ed Minicul4*.or The remote controlled manipulacor seYves as a transcort vehicle for inscaction or recair toutcmen,t inside 'a steam generst:r crimary head.

The manipulator consists of two major ccmconents; the maniculat:r leg and manipulator arm. The manipulator leg is installed between the tube sheet and bottem of the primary head and orovides axial '

movement of the arm. The manipulatcr arm is divided into the head arm, probe arm and a swivel arm. Each arm is moved indecendently with electric teters witn enc:dar position control. The twivel trm e

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1432(8402)/js-27,

. . i allows motion for tool alignment in both scua're pitch and' triangular

• p pitch tube arrays. Comcuter control of the manipulator allows the ~

operator to move sleeving tools frem outside the manway and accurately position them against the tube sheet. -

4.6.2 Manipulator Elevator .

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4.6.3 Tube 3rushino-Cleaning foutoment

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4.6.3 Nendestructive Etaminatten .

Three types of nondestructive examination equipment are used during the sleeving process. They are as fo11cus: eddy current testing (ET) equipment, ultrasoni,c testing (UT) equicment and visual equipment.

A dual cross wound probe and' bobbin probe usin the multifrequency eddy current method will be used to do a base ine inspection of the

• installed sleeve for future reference. The ET fixture with concuit is used on the manipulator arm to position the probe. Eddy current testing using a bobbin probe may also be used to determine the -

inside diameter of the tube to be sleeved and the sleeve expansion size.

Ultrasonic testing using an imersion technique with domineralized water as a couglant is used to inspect the uocer tuce to sleeve weld. A one-quarter inch diameter focusing transducer is positioned in the weld area by the elevator and is rotated with an electric motor to scan the weld. The pulse echo tester has the ability to interface with an on line data redue:1cn computer to produce a display /hardcopy during radial and axial scanning.

Visual inspection of the uccer and Icwer tube to sleeve weld is accemplished with the use of a boroscope mounted on the manipulator arm. .

4.1 PLUG INSTALLATION EQUIPMENT The equipment used for remote installation of plugs in a sleeve steam generator tube is made up of the following fystems:

, 1. Remote Controlled Manipulator v -

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5. Nondestructive E.tamination foutcment /

a.7.1 Recte Control 94niou14ter See Section 4.6.1 for a description of t.*e temote Centec1 Manipulator.

4.7.2 Sleeve tira s ollino Ecutement 0 .

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N 4.7.3 Plug Installation Ecuiement

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4.7.4 Plug Welding Ecuiement

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4,7.5 Nondestmetivg Examination ,

a Visual inspection of the plug weld is ac:omolished with the use of a boroscope mounted on the manipulator am.

4.8 ALA M C0tl3!OEAATI0t5 .

' The staan generator repair operation is designed to minimi:e personnel exposure during installation of sleeves or plugs, the a

maniculator is installed from the manway without entering the steam generator. It is coersted remotely from a control station outside the containment building. The positioning accuracy of the mantoulator is such that it cap be remotely positioned without having to install temolates is the steem generator.

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Air, water and electrical sucaly lines for the tooling are designed and maintained so that they do not becemo entangled during oceration. This minimizes personnel excesure cutside the steam generator. Except for the' welding power source and programer all g equipment is ocerated frem outside thee containment. The power source and progrsmer is stationed toout a hundred feet frem the steam generator in a low radiation area.

• In sumary, the steam generator operation is designed to minimize personnel exposure and is in full comoltance with ALARA standards. .

4.9 RETIRENCt3 70 5tCT!0N 1.0 (1) Sedricks AJ J., Schult:, J. W., and Cordovi, M. A., "!nconel Alloy 690 - A New Corrosion Resistant Material", Jaoan 5cciety ofCorrosionEncinagring,g,2(1979).

(2) Airey, G. P., "Octimization of Metallurgical Variables to "

Improve the Stress Corrosion Resistance of Inconel 600",

tiectric Power Research Institute Researen Progrsm RP17C8-1 (1982).

(3) Airey, G. P., Vata, A. R., and Asoden. R. G., "A Stress Corro.

sien Cracking tvaluation of Inconel 690 for Steam Generator

• Tubing Apolications", Nuclear Tecnnnincy, ~59,'(Novemoer,1981) 436.

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• 1432(8402)/js-33, 5.0 SLEEVE EXA.w!NAft0N PROGRAM e

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5.1 ULTRA!ONIC !NSPECTION .

5.1.1 symmary and canctustens An ultrasenic examination is used to confirm fusion of the sleeve to

, the tute'atter welding. 'his tart consists of introducing a sound wave with a frequency of . into the welded region. This sound e

wave is rotated 360 de around the tuce, the fixture is tnen -

' esised approximately(gree;. inches and scanned again. A minimum of three scans are performed and if one or more of these scans show fusion for the wnole 360 degrees, the weld is considertd acrectable.

The team that is used is capable of , easily detecting 4( inch diameter flat bottemed hole. ' ,

$.1.2 Ultettrnie (valuation Ultrasonic technicues are emcloyed to confirm tse presence of sleeve tube weld fusion. The evaluation 1 were.made of Incanel 690 alloy sleeves with ne inal jimensions o jinchoutside diameter, and minieu Jinchwall. ihe Inc:nel 600 tifoy steam generator tubes are 0. 75 inen Weld Sosition is RCor3Aimatelyf_outstje 11ameter j'nCnes#r0mtne100 Oft *e 4 0.0!O inen as1 sleeve.

Ultrasonic contained waterenergy column at( in tne vicinity of tne meld.lisemittedfrema After passing into the sleeve at its entry point, the ::und ::ntinues to trtvel 11

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1432(8402)/js-34 until it arrives at a separation in material'or te the cocesite side -

of the material. The transducer is designed so that when trave 11ng through the total thickness of sleeve, weld and tube, the energy is focused at th sleeve o er diameter wall, with a soot si:e of approximately ' '

When sound enters the sleeve seme of the scund energy is reflected at the sleeve !.0 and the reflection is referred to as the interface signal. The trtnsmitted sound passes througn a weld with

,' procer fusion and is scmetime), but not always reflected back to the transmitter frem the tube bacxwallt i.e., the tube 0.0. Sheuld no fusion exist at a given point, the sound energy aill be reflected at -

the sleeve backwall, i.e. the sleeve 0.0. A wg1d ares is considered

. to have proper fusion where an interface signal exists withcut the presence of sleeve backwall reflection. . A gcod weld is shewn in .

Figure 5-1 where the tube backwall signal is also present. No

,1 fusion is shown in Figure 5-2 where the display in the cathode ray tube JCRT) shows the interface signal fo11cwed by a sleeve backwall signal. Sometimes when there is lack of fusion the interface signal is followed by multiple sleeve backwall signals.

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The weld examination begins when the transducer is inserted into the sleeve / tube assembly to a position such that the transducer is aligned with the' weld. The trsnsducer is then rotated 360 degrees at this elevation and the degree of fusion is deternined by observing the ultrasonic instr'. ment's CAT, or by other readcuts.

Additional scans at other elevations can be performed to eyeluate the complete weld area.

In this manner, the weld integrity c y be ass r ed and lack od

• fusion, with an ares equivalent to al. l diameter flat nottom hole or a slot with a width of[ , qan" reliably be detected.

In actual test scocimens, a lacx of fus on had been reliably detected as shewn in Figure 9 2. ~ '

5.1.3 Tatt tauf erant Test soufoment for welded sleeve inspection consists of the following ccmoonents: .

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1432(8402)/js.35 0

5.1.4 Defect $4 moles

• Qualification of the ultrasenic inspection system was made through a variety of pedigree defect samples, as well as welds with good ,

fusion across the entire area. Weld samples are troical of conditions to be present in the steam generator. The calibration samples are described as follows: i

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5.1.5 '

Detailed'Retutes .

, The ecmouter autout for each calibration sample is included in this

' report. The information contained on each chart consists of'the

' following:

1. Rotation (degrees). This is the angular position of the trsnsducer measured in cegrees.' The zero degree coint for tne transducer is arsitrsrily selected, locked into place and is consistent for all fo11 ewing scans, this enaeles circumferential location of any lack of fusion area indicated on the print out.

2. tievation (inches or cantimeters). The elevation or vertical '

position of the trsnsducer within the sleeve is givei in botn inches and centimeters. This information enables acoriximation of the weld heign; and location of any lack of 'usion s*ess, e

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1432(8402)/js=16, c

3. Scan limits. The upper and lower scan l'imits for the weld are '

sacwn by the unprinted section of the scan Itmit figure.

4 Cata on the too of sich enart relates to infomation concerning ,

the inspected tube, steam generator and time as signal amplitude threshold values fp rer.1rdIng.There well 4re as weld two sleeve-tube areas that can be monitored oy electrcnic gating circuits. One gate 7easures .the level of the signsi from the tube outer surface ar4 the other gate mitors .the sleeve-wee g interface. A tube outer. surface ' signal aoove the 'thresdohf '

value and/or no sleeve signal a>ove the threthold value com' ' #

indicate fusion. , s Y u .

Gate 1, the tube backwall monitor, is positioned so that its leading edge aligns with the leading edge nf.tne Nbe backwell .

signal.

Gate 2, the sleeve bachull nohter, is cositioned sci (?s leading edge follows the interfa'*e signal ano terminatec cefore the tube backwall signal.' '

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The ccmputer lofblare allows *grsatility with regard tf a monitoring the wold integrity by selectit% of t,'e gates to be used, as well at the setting of the threshcl.111wf 44. The normal inspection ti cerformed'b/ moniter#c) on1/ t?e-

sleeve tube signal (Gats ?', #tr.eut incard to the tute backwall -

signals (Gate 1). .-

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In reviewing the ccmouter readouts for t'he two calibration samples $

used, the following analysis is ofdered: 4-

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!t can be seen that each of the artificial flaws used for these qualification examinations can be detected, wnfle the good 'usion areas of the weld presented so indicated areas of lack of fusion.

• 3.2 (00Y CURAINT IN!PECTION .

~

The objective of this examination is to estaolisn baseline dati cn '

i the primary pressure boundary of the sleeve =tute asset.bly. Ne ,

o ,

34

1432(8402)/js-37 examination was develoced to detect 40 cercent AS.vt sized flaws in -

the parent tuce and/or sleeve in any region of the sleeve-tuce assembly with a single pass of an addy cur gnt coil.

5.2.1 Sumarv and conclusions .

An eddy current test has been qual.ified for the inscection of installed welded sleeves to detect flaws in the pressure beundary.

Eddy currents circulating in the sleeve and steam generator tube are i

interrusted by the presence of flaws 1,n the material with a resultant change in test co11* impedance. This impedance change is crocessed and displayed on the test instrument to indicate the .

present.a of a flaw.

• The pressure boundary is considered to be the sleeve up to and '

including the uocer weld joint and the steam generster tube above the weld. Consequently, there are three distinct regions relative

. to the inspection methods: 1) The sleeve belcw the weld, 2) the steam weld) generator and 3) thepube behind steam the top generator tubesection aboveofthe thesleeve.

sleeve (above the Mt Using specialized probes and mu tifrequency eddy current techniques, it has been demonstr ed that a is detect le anywhere in the sleeve or tube.

including the weld rtgfon (

9

% The test results are recorded on -

S . magnetic tape and strip ch t recordings. Other than the probes, a , the inspection equipment is the same as used for a convention,a1 eddy t'c 1%

current test of steam generator tubing. Additions 1 laboratory -

's .

testing of . accelerated corrosion samples has shown that this method can detect 10300 in the parent tube.

'N  %

$ + x -

4.2.2 .*ulti Frequency Eddy Current Ecutement Recuiremenis f,% * , '

The equipment required to perfor-n this examination include the

, . folicwing: 3 i r e m 3- .

cs ,

i p.e y

                                                                                                                                                              ~

I.2.3 'Davect smolas W , A variety of sitrulated defect samoles were fi ericatec to recrosent .v different :ossible flaw locations in the sleeve or steam gereritor "N tube. The bests f tne qualification was to semenstrate e

        >                     e' detectability of a s             ,

s* n p f -. 9 j . 55

 ~

u .

                                      ~

Y

~ < . .                                                   .

g . .. ..

            *}                                                                                                                                                                                                                              (~

1432(8402)/js-38s -

                 ~'.

3at any location in the pressure' boundary. Several *

                "'                                              samples were required to simulate the potential signal inter #erence from the sleeva end, sleeve bulge and weld. The samole matrix included:                                                                                                                                                    -
                     . %.                                 >                                                                                                                                                                              s        .

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       ~

i

                                               \

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                                                         .k                                                                                                                                                                             j 5.,2.4 -                  .

Results and Conclusions * '

                                                                      1 g s                                            y; s,                                                                                                                                          .
             ..t e

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                 .ct
                 ~                         4 a                                                                    .
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l l s I [ ] multi-frequency eddy current techniques are emolayed to further enhance the signal to noise ratio. A total of four separate test frecuencies and two 5-6

                                                                                                                                                                                                                                                ~              '1

_j . i

• 1432(84'2)/js-39, 0

t

                                     - mixing-chinnels~ are emoloyed simultanecusly'. I By combining the

• signals from two frequencies, the residual noise signals frem the

,NC                                     bulge, etc., can be virtua',1v eliminated. For this particular
                                      , application, a combination,                                -
.i$                                                                                                        - Jis
                                     .used.to inspect the_ sleeve. In Figures 5-11 through 5-15, the eddy current test signals for various qualification samples are shown,
                                     .both the single and multi-frecuency ,esults are shown, however, in
                                                                  ~

g

                                     -general,the{

analysis. jwillbeusedasthebasisof The low frequency recuired to examine the steam generator tube *

                                     .through the sleeve and the totalw'all thickness of the sleeve-tube i

assembly result in insufficient phase shift of the defect signals from the steam generator tube defect calibration standard to allow - evaluation of steam generator tube wall degradation indications by relating signal phase angle to the death of penetration. Consequently, detection is possible, but accurate sizing generally is not possible.t Sleeve wall degradation indications can be evaluated f r depth of .. . _ penetration and origin by plotting the phase angle of data to graphs relating signal phase angle to death or penetration. ' The smallest sleeve wall degradation demonstgated to be detectable with this. examination technique was a stiglet, from the 0.D. of the sleeve. 5.3 -VISUAL. INSPECTION ~ 4 5.3.1 Sumary and Conclusions B Visual examinations are performed on the upper and lower sleeve to tube welds to determine their integrity and accuot'ance. The welds C 'are examined using a fiber optic or boroscope examination system. The lighting is supplied either as an integral part of the visual

• examination system or as a sucplemental system. Each examination is recorded on video _ tape for optional later viewing and to provide a pemanent record of each weld's condition.

The inspections are perfomed to aschrtain the mechanical and structural condition of eacn weld. Cr'itical conditions whien are checked include weld width and completeness and :ne absence of visibly. noticeable indications suen as cracks, pits, blow holes, burn thrcugh, etc. 5.3.2 ~ Lower Weld Evaluation

• The lower weld of the sleeve-tube assembly is insoected using a boroscoce examination system. The boroscope is :ositioneo uncer the lower weld and the lighting is acjusted to obtain the optimal viewing conditions. Rotating the boroscope around the weld and y
• tilting it when necessary, provides complete coverage of the 5-7

I? , 1 ... - 1 1432(8402)/js-40, examination area. A videotape recording is made of the entire ~ examinations.

                                 ; Prior to the inspection, the system's accuracy is ascertained by            ,

observing a 1/32" black line on an 13% neutral gray card placed on the surface to be examined or a location similar to the inspection area. Procer use of this system provides image resolutien on the order of 0.001 inch. , . T Weld acceptance is based on the absence of any cracks or other visible imperfections which would be detrimental to the intege y cf the weld. During the examination, an area containing a noticable ' indication is inspected more closeiy. This is done by varying the a light intensity, distance frem the lens to the indication, and/or the angle used during the viewing. . - 5.3.3 Uccer Weld Examination A visual examination is made of the upper sleeve to tube weld uring a boroscope inspection system. This system utilizes a right-angle

                                  -lens and a tool which can deliver the lens up to the weld as well as to provide 360* rotational capabilities.

To perfann the inspection, the optics system is inserted into the sleeve / tube assembly such that the lens is located at the uoper weld. After checking for visual clarity and adjusting the lighting to reduce unwanted glare, the lens is rotated 360'. The lens may then be raised or lowered and the process repeated to ensure complete weld coverage. The entire examination is, video-taped for a ,

                    ,              permanent r,ecord.

Prior to the inspection, the system's adequacy is checked by observing a 1/32" black line ca an 18% neutral gray card placed in a

                                , location'similar to the area to be inspected. Additionally, to obtain an aspect for size and to check the in-tube lighting, a
                              ~

welded sleeve-type sample with a .020" diameter througn hole is placed over the lens. - The weld acceptance is based on the absence of cracks or other visible imperfections ~which would-be detrimental to the integrity of the weld. Detrimental imcerfections' include blow holes, burn thr0ugn, weld mismatch, etc.. Curing t'he examination, any area wnich contains noticable imcerfections is examineo : ore closely by varying the light intensity and/or the cositien of the lens with res:ect to the indication. 5.3.a Test Ecuiement ' The test equiement necessary to visually insoect the uccer and icwer sleeve to tube welds consists of the folicwing:

.s.            ',                                                                                                          l l

5-8 l l

y- - 1 f . 1432(8402)/j s-41._

1. Boroscope visual examination system with' an integral lighting - - i system, lenses and a delivery and rotational tool for inspecting the upper and 1.cwer welds.

                                       '2.   '18% neutral gray card with a 1/32" black:line.                                 '

3. Welded ' sleeve-tube sample with a .020 inch diameter through drilled hole.

4 Video camera and recording ecuierant.

                          -5.3.5        Defect Standards                                                                       -
                                    .: _Various methods are used to determine system adecuacy and to aid in determining weld acceptability.                    ,-                                       . <

1. System adequacy, including lighting intensity and camera system clarity is verified by. resolving a 1/32" black line en an-18.

neutral. gray card. 2 .~ Size aspect for upper weld inscections is obtained by viewine a welded sleeve-tube sample which has a .020 inch thrcugh drilfed

  ;e.

hole. . 3.. Sleeve-tube upoer and-Icwer welds were made with both ._ acceptable welds and intentional weld malformities. These welds were photographed and are used as aids to examiner. e 4 e p f s a 9 5-9

k. ,

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6.0 SLEEVE-TUEE CORRCSION TEST P CGRAM 3 C-E has ' conducted a number of benen and auccclava tests to evaluate the corresion resistance of the welded sleeve joint. Of particular . Interes:-is the effect of tne mechanical expansion / weld residual stresses and the condition of the weld and weld heat affected :cne. Various tests have or are presently being conducted under - accelerated conditions to, assess the sleeve-tube joint cerformance under potential nominal and fault environmental conditions. An outline of these tests is shcwn in Table 6-1.C e

                                                                              ,J                                                .
                       '6.1            SUW.ARY AliD CONCLUSIONS

(_ - s J 6.2 TEST DESCRIPTION AND RESULTS 6.2.1 Modified Huey Tests e e e i,

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      ._.     . _ . -                   -_'    ).._.              .

1432(8402)/js-47 0

6.3 REFERENCES

FOR SECTION 6.0 *

1. I. L. W. Wilson and R. G. Aspden, " Caustic Stress Corrosion Cracking of Iron-Nickel-Chromium Alicys." Stress Corrosien Crackina and Hydroceg Embrittlement of Iron Base Alievs, NACE, Houston, Texas, pp 1A89-1204, 1977.

3 .

2. A. J. Sedriks, S. Floraen, and A. R. McIlree, "The Effect of .

Nickel Content on the Stress. Corrosien Resistance of Fe-Cc-Ni in an Elevated Temperature Caustic Environment". Corrosion, Vol . 32, No. 4, pp 157-158, April 1976.

3. F. W. Pement, I. L. W. Wilson and R. G. Aspden, " Stress Corrosion Cracking Studies of High Nickel Austantic Alloys in Several High Temperature Agueous Solutions." Materials Performance! Vol.19, pp 43-49, April 1980.

4 P..Berge and J. R. Donati, " Materials Requirements for Pressurized Water Reactor Steam Generator Tubing." Nuclear Technolcov..Vol. 55, pp 88-104, October 1981.

5. G. P. Airey, A. R. Vaia and R. G. Asaden, "A Stress Corrosion Cracking Evaluation of Inc:nel 690 for Steam Generater Tubing

                    ,               Applicaticns." Nuclear Technolocy, Vol. 55, pp a36-448, November 1981..
                ,               6. J. 'R. Crum and R. C. Scarberry, " Corrosion Testing of Inconel

• Alloy '690 for PWR Steam Generaters." Jcurnal of Materials for Enercy Svstems, Vol. 4, No. 3, pp 125-130, Cecemcer 19e2.

          '                a f

1 5-6

g , 1432(8402)/js 48 7.0~ MECHANICAL TESTS OF SLEE'/ED AND ? LUGGED STEMI GENERATOR TUBES 7.1

SUMMARY

'AND CCNCLUSIONS Mechanical tests were performed on mockuo steam generator tubes . containing sleeves and plugs to provide qualified test data describ-ingthebasiccrepertiesoftheccmoteredassemblies.C 3 .

                                                                                                                                               .)

g . 3 The welded plugs'have sufficient load capacity to perform their function during normal and postulated accident conditions. The axial load required to loosen the plug from the sleeve-tube assemolv~

                           ,        is approximately fcur times greater than the design load.

7.2 CONDITIONS TESTED . ( . 3

                ,               '[

J ~ 7.3 WELCED SLEE'/E TEST PARAMETERS AND RESU,LTS T.3.1 . axial ?u11 Tests

                             ~~
                                                                                                                                                  ~

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8.0 STRUCTURAL ANALYSIS OF 51.II'/E USE A55EM5!.? It is :he pur;csa Of this analysis .: es:::lish :he structural adecuacy of the sleeve-tuce assamcly. The methodelegy used is in ac rdance witn the ASiE 3ciler and Pressure 'lessel Code, Sectica III. The wert was ;crformed in a . anner in ac: rdance with 10C.7950 Appendix 3. requirements Also, are ze:. it is construc:ad such ths; all U.S. Regulat:ry i- ' 3.1 SWFMY AMO CCICLUSIONS Based en the analytical evalua:1cn' c:ntained in this secticn and :ne

                                      , tachnical test. data centained in Section 7.0, it is c:nclucac -hat the welded tube sleeve, described in this.c:cu=en:, meets all ne                                                                                                         -

requirement: stipula:2d in Sectica 3.0 witn sucstantial adci;ional margins. 8.1.l' Oesien Sizina , In ac: rdanca. with ASi! C0de practica, the design recuirements f:r tucing is covered by the s:ecifica:1cn for :he steam generater

• vessel". The accr:;riate formula f:r calculating :he . inimum required tuce er sleeve thickness is fcund in Paragracn NS-2224.1, tentative pressure thickness for cylindrical shells. The felicw-ing calculatten uses this for=ula.

5 .5 P Where = Min re:uired wall :hicx (in.) 3

                               -              t-            .
                                                                                                     . P = Cesign Tutesheet dif'erential cressure '

t= (ksi)- l-R = Inside Racius (in) _J 5* = Design Stress Intensity (5.I.)

                                                                                                 ;                                                                                (per Ref. 8.2)
                                            =
                      ,                       s-                                                4                                                                                                           '
                                                                                 .                                                                                       +

i 3.1.2 Cetafied Anaivsis Scenari When :r:cerly ins:siied anc weicec wiinin s:ecified ::lerancas. ONe ' sleeve and i:s <c :rimary weics :cssess ::nsicera:ie targin aga 9s:

                                      ;ull-cut fer all c:ncaiva:Te Icacing un :n :an :e :cs:uistac.

o

    +

3 '. ht . - _ _ _ _ _ _ _ . _ _ _ _ - - - - - _ - - _ - _ _ - - - - - - - - --

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                                                  -- { (,------                                  . . , , . , _ _ , _ _ .                        .

1 l Decencing the sleeve d: nc: en ce degree 3(af excaec gentube /:uc;cr-=e c:nsidering Icekbac, favencle txf al Icacs i results fr = :te

                                             .,]fadgue       cycife precie:s  areacading no: andc :asu(i;acc .

In Secdca 3.2, a c=carisen is made between calculated failuru =ccas and tas; data discussad in Secdon' 7.0 cf : tis recert. Tne agreemen; between calculatsd and :at: data was g:cd. Safety fact:rs were de-tar:1 red for hyccchedcal pipe breax accidents, and a mini == fac;;r

     '                                                   ]was,detar=ined.

of safety safety wasf- of{,] based en :te The ne;cwer full mal coerations restr2inec fac :r ofthermal ex icading. Tusncu; 1 =e Icwer sleeve /tuce s us joint is =a en -

                                 . cridcal c:nsideraden (see Secden 3.4.5) .

Tne axial sleevt icad: calculated in Secden 3.s are usec as '

                               . bcundar/

Section c and S.5 nditions anc'=eevaluations. 3.7 fadgue basis for assum dens usec in ce An NRC. Regulat:r/ Guide !.in evaluaden was :er" med in See:1cn 8.3 :s detarmine a sleeved :ude :: Tugging limi;. A hitewacie degraca:1cn limit was detarained. Bis is cssible[ OcTausa =e Reg. Guida specifically usas nemal c eradng ;an=etars, sucn as ccerating dif#erendal pres:ure, n:her =an tubesneet design differential pressure. Consideratient of suscapdbilt:y ta ficw incucac vibratien was dis-cussed in Secticn 3.5. Based en C-E ex:erienca and tas; data, it was datar=ined than a nor=al:ta a sleeved tuce is no cre suscandble :: vibraticn tube.

• Fadgue of 5'ot.'t the uccer and icwer joints was c:nsidered in !ecten 3.5. De gec=etry was snewn :c meet all ASME C de alicwacie stress intensities inclucing lccal :rimar/ and ranga cf primar/ Olus sec= -

ar/ stress. A utuladen of de resul: is presange in i'acle 3-!. he maximu= iccal primary stress'in:ansity was( p si acr:ss ce les e a: ce icwer weld joint, as c:::ared wi= ce alicwa:le Of i ksi, ne maximu= range of Orimary :lus sac = car / s;nss was ksi acr:ss ce sleeve a: gne icwer joint, near =e weic, as c:= cared wjtt ce alicuacle c4 ]isi. De maximum fadsue usage fac=r was 0.49 a: ce same 1cca:icn. Bis M due in :ar(: = ]c:nsisun !y ::nsern:'iv,e dens assum:gn race in usage=e fac::r was calcula:1cn. * ' d 5'eeve and evaluatten 24 inch near bundlewas :er :r ec f r 25 iner sleeves in ce centrai tube bund peripnery. De =emai m: a:= :e reen me sleeve and tuce wnica affects cistance etween ne =:: of me =:e sneet axial

                                                                                ~

10acs :enn Over i s.".0r. - an: ce 2::er set . ~~e r?I A:iveofsaveri:7 functicn =a cf Ois:anca me axial Icact WC' = tre tevei :ec are a civicec Oy me OveraM :isur a

enveen ne u::er anc Icwer ,,eids.

J E..

pt--- o A sleeved tube :1ug was suc:sssfully evaluated in See: ten a.7 in - case it should ever be needed (see 7acie 3-1 and Acpendix 3C). 3.2 .LCACING3 COMSICERED . In this secticn a neccer of potantial failure :cces art eAa.uined :: determine tne relative safety margins for selected events. Tailure leads are calculatad based on mini =um dimensions and :::ared with mechanical tasting results fr:m Secticn 7.0. Sc:h calculatad and

     )

measured Icads art c:m:ared with :ne m;ximum pcstulated Icacs. 3.2.1 _Uccer Tube 'deld :ulicut Lead - Assuming the ;aren: :ubeis:::alkysevered,theminimum1 cad recuired to shear the u:per tuce weld is calculatad. The fer:e required to pull the expanded sleeve :hr:'ugn the unexpanded :uce is . censervatively neglected. f I I i

                      .       ~                  .

In the event of a main staam line break (MSL3) ac:ident Me seconcary pressure wculd dr:c curing a shcr; -ice Lnterval. The primary :ressure would rise briefly : ten felicw the dr o in - sec:ndary Ortssure. It will be c:nserva:ively assumac ::a: full

            ,                        rimary crassure remains wnen :ne sec:ncar
                                ' Postulating a main s;aam line break (MSL3)yacciden:,:ressure reacnes    :ero.

e taximum available lead wcule te:

i s 3.2.2 L:we* 5:ve '4eic :us..aut '.:ac Assuming :ne :aren: a:e is ::al'y severec, ne mindmum ::ac . recuirec :: ru::ure :ne lower s:ua neic is ca:cula:ec. *: 's in ! resting :: nc a tha* # r :nis gecmetry, Isec 03 Ne :es *, resul s, :ne nel: 'iJ n - *ati in :urt snear. e s

                                                                    $=3

4 -

• i~ne weld lio seemed to " roll cver" as is tiiuttrated in Figure 3.2 such that the weld faf f ec primarily in tensicn.

Weld area = weld threa: - circumferenca

• J Frem Referencas 3.1 and 3.2, the minimum : ensile s:rengta is 30.0 ksi. Therefore, a predic:ad ";ushcut dIcad en :ne sleeve sign: be

                                         . calculated:

1. , . .

l

                                                                                    .                                                        l     '

L- . . Ecstulating a icss of crimary c:clant acciden: (LCCA) curing hot standby conditions (0% power), Me maxi.tum available Icac wculd be: r *

   .                                                             f 3.2.3                 Weld Faticue L

Since the factors of safety are qui a hign f:r Icadings due :s

• primary stress, :ne mecnanism of grea:est interest is ne fatigue failure operation.

ncrmal ecde due to varisole axial leading of ne sleeve curing In See:1cn 3.3, fatigue evaluaticas of bo 3 the u::er and !cwer welds, whica join :te sleeve to the tute will be race. :: is #1rs: necessary : cetermine the effec;s, wnich :::e lec.g-uc witnin :he tubesnee:*and tuce succor; plates tave en :ne axdal leacs in :ne 4 leave during normal ccerstion. "This sucjec: is accressad in Section 3.4

                 ' 3.3                   REGUL;7CR't GUICE 1.121 DALUATICM FOR ALLCWAELI SLIDE WALL CEGRACATICH                   ,

R.3. 1.12* (Referenca 3.3) -ecaires tha a ?.ini um sc:at ::!e :::e (Or sleeve) mall nicxness :e as: :!f sr.'ec :: :r:v d :s a :ac t s #:r remCVing i :::e #*0m servica. Ecr :ar*iti ;Or*J-waI* 1;;acx #rt?. ary s0ur:e, *ne recuiremen

• f1II in **vc 01:eq0rdes , 'ai ac r"*ai acert:icn safety targins, and (b) c:nsicert:1:ns es*a:ac ::

cstulatec : ice au::ure ac:icents.

3-4

                                                                                                                     )                                                              __                                  . . _                                             _        ..

t T e i

                         , . 8.3.1                                                   Nor-'al Ocoratien Safaty . var;rns

• It is the general intant Of these recuitecents :: :sintain the same fact:rs of safety in evaluating degraced :uces as -hose inica wre .

c:ntained in :he crfginal c:nstructicn c:de, ASE 3a11er anc Pressure 'tessel C:ce, Sec fon !!! (Reference 3.1). , For Inc:nal Alicy e00 and .590 t'de c sleeve material the

                                                                                  -c:ntrolling safety margin is:

g . . diubes with par, :nru-.all cracks, was:3ge er c:=binaticns of these , shculd have a fac cr of safety aga.f as failure cy cursting uncer ' nor .al c;:erating c:nditions of not less than 3 a: any :::e

                                                                             ~
                                                                               . Iccati:n . d s

f i'

                                                                                                                                                                                                                                                                                          }
                                                                                                  .                                                                                                                                                                                       I i

t i 1 6 i

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O + [ i l i ( i

• h i

D r

                                                                         =

0 e

                                                                                                                                                                                                      !-T
              -_         __________________-_-__._,_-._______-____m_                                   . - _ _ . _..m   _ _ . _ . _ . . _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - . _ . . _ .                    __.m._     _ _ _ . _ , _ _ _ . - . _ _ . . . . -

                                                              . )                  .-

W 4 veujs-a - o 3.3 R . .:<E'ICII FCR SECCC 13.0 3.1 ASME Ecif er and Pres:urt 'lessel 2ca, Sectier. I:: f:r Nuclear . Pcwer Plan: C :::ccents. 3.1 ASME 2ciler and Pressure Vessel C de Case N-20, !3-153 titckel-Chr:mium-Iron Tubing (A11cys 500 and 690) at a 5:ecifiec Minima Yield. Strength of 40.0 XSI. i

8. .! U.S. ilRC Regulat:ry Guide"1.121. "Sases f:r Flugging Cegraded PM Staact Generat:r Tuces '. . '

                              . 8.1 RFQ frem Swedish Stata ?cwer Scare, SIV1-Un/Gn-4331, da:cd January 4, 1984,. :: C-E Fewer Systems, f:r Ringnals I Staam                                                                                  -

Generat:r Cemcnstraticn Sleeving. 3.5 Lettar. E. L. Wat:1 (NSF) :: R. 3. Grans: and (CE), datad July 20. 1924, "Prairio Island Gecme:Mc anc Crerating Parame:ars". 3*:* 53F3 S:ecifiestian for Reciacaman: Steam Genera::r f:r tinghair 1 ?luclear Feuer 71an , datac JanJar/ L384 8.7 - Intarnational Nickel Co. Ecckler, "!ne:nel 650". 8.3 Nuclear Systams MataMais Hancheck, Voluma 1 *0esign Ca:1", Par: I, Grcus 4, Sec ion 3 - Inc:nel Alicy 600. 3.9 '"libratica in Nuclear Hea; Exchangert Cue :c Licuic anc Two-Fhase Ficw!', By W J. Heilker and R. Q. Vincant, Jcurnal cf EngineeMng for Pcwer, Voluca 103, ?sges 355-255, AcM1 1531. 3.10 "ANSYS', EngineeMng Analysis System, User's Manual, by Jenn A. Swan:cn. 8'.11 E?RI NP-1479, ' Effec cf Cut-of clane Centing L:ac: On :ne

            '                           Stractural Integrity of Staam Generat:r In:arnals, 2n:rac::r:

C-E, August 19E0. 3.12 ?M:ary/See:ndary Scuncar/ Cem:enents Steacy Sta:a I:rts-Evaluatien', Frt:ared by Raymenc dtui Wedler, Westing F.ec:rde Cert., AoM 1 1965. , e h 3-!!

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l L'l g _ , 1432(8402)/js ~7-

     .p                          10.0            EFFECT dF' SLEEVING ON OPERAT'ON An analysis was performed to determine the effect of . ins,talling
                                              ' welded sleeves in the steam generators. It was assumed that two                                                        -

'* - thousand sleeves wculd be installed in each steam generator. Since-it is not kncwn how many 36" long and how many .24" long sleeves

       '                                         will be installed; it was conservatively assumed that all sleeves
                                                        ~

were 35" long. Using the pumo characteristic curve and the system 1.. resistanca curve, the flow rate change was determined for increased in totiil' ficw rate'was only[and flow shculd Yesistance. associated with } installing not have a significant - effect on. reactor oceration. - f. s 0 0

           ?        E 9

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                                              -         )_ _                               ..

1432(8402)/,1s-Ed '. m , #

     .)                                                                  .       .

APPENDIX A TO REPORT NO - PROCESS AND WELO' 0PERATOR 00ALIFICATIONS

                                                      - FdR TUSE SLEE'/E AND PLUGGING SLEEVED TUBES 4

4 , 9 8 9 9

                       -t I
 -4 A-1
   =

 ,       -+--

1 1432(StD2)/js-59, APPENDIX A A.1-'SLEE'/E WELDING AND SLEEVE WELCER QUALIF!CATICN

                                                                        ~
                    ; Sleeve welding is qualified using an approved test precedure (Reference 1).

Flug welding in sleeved tubes is qualified using an accroved test procedure 3- -(Reference'2). The sleeving test precedure is in ccmpliance with acplicable sections of the' ASME Code even thcugh it does not directly acply to sleeves,: and-the plugging procedure is in ccmpliance,with Section XI of the latest ~ edition of the ASME Code. Sleeve and plug welders are cualified using test records =in accordance with applicable sections of the Code.

                     .The test procedures specify the requirements for performing the welds, the
                     ~
   .                - conditiens (or changes) which require requalification, the method for
                       .xamining the welded test assemblies and tne requirements for qualifying the---~~~--~   ----

welding cperators. Sleeve 4and plug welding are cualified 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. O k A-2

p-.

                                                     ..1 t:

[ ,- $1432(8402)/js-60 M . p: A.2 REFERENCES TO APPENDIX A-

1. Welded Steam Generator Tube Sleeve Semi-Autcinatic Gas Tungsten

_ Arc Detached Welding Procedure Qualification,

                                         - Test Precedure 000CO-MCM-050, Rev. 00, April 14,1984

2. . Engineering Requirements for Plugging Sleeve Tubes in

_3 Westingncuse Series 44-and 51 Steam Generators, NCE Engineering Procedure EP-6275G-lC4 Rev. O, April' 19, 1994 t 4 g i f. c 9

                     .0 f

k m. 9 p. A-3 s. ,i L}}