steam generator reference book

Steam Generator Reference Book

Technical Report

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SUMMARYEPRI Leadership in Electrification REP 0 R Tthrough Global Collaboration------------------

Steam Generator Reference Book, Revision 1Volume 1

The Steam Generator Reference Book documents the state of the artin PWR steam generator technology, providing a comprehensivesource for operators, owners, and designers of PWR nuclear powerplants. The book summarizes pertinent steam generator operatingissues and provides recommendations to improve operational effi-ciency. Information in the book represents 15 years of research anddevelopment actiVity over the course of several hundred researchprojects involving PWR steam generator issues.

INTEREST CATEGORIES

Steam generator reliabilityNuclear componentreliability

Nuclear plant operationsand maintenance

Advanced light waterreactors

KEYWORDS

Nuclear steam generatorsComponent reliabilityCorrosionWater chemistryMaintenance

BACKGROUND In 1977, EPRI established the Steam Generator Project Office inthe Nuclear Power Division to manage research and development (R&D) leading toresolution of operational challenges associated with PWR steam generators. Underthe charter of the Steam Generator Owners Groups I and II followed by the SteamGenerator Reliability Project, EPRI staff worked on this project in conjunction withparticipating utilities. The results of this work have been documented in severalhundred EPRI reports and papers. Additionally, research results from internationalassociates have been incorporated with EPRI and U.S. utility results. Altogether,these activities have resulted in a significant increase in steam generator avail-ability, and in a reduction in lost capacity due to forced outages.

OBJECTIVE To integrate and summarize current PWR steam generator technol-ogy; to recommend design, operating, and maintenance improvements that willincrease plant availability and life.

APPROACH EPRI editors arranged the R&D results by operational issue andassigned EPRI staff and key consultants/contractors to collect, organize, and writechapters relating to each issue. Specifically, chapters in the Steam GeneratorReference Book address each of the known and anticipated steam generatorchallenges and the factors affecting them. Included are causes of steam generatorunavailability as well as possible actions to minimize problems. For ease ofretrieval, recommendations from all chapters are listed in Chapter 4. Each arealissue has been critically reviewed by the editors, EPRI staff, and other experts inthe field.

RESULTS The Steam Generator Reference Book summarizes options and rec-ommendations for improving the operating life of PWR steam generators. Optionswill be utility specific and will depend on such factors as the age of the plant, design/construction, plant siting, and utility policies. The book emphasizes a variety ofdamage forms, addressing environmental factors likely to accelerate or inhibit!control damage initiation and growth. Recommendations describe modifications towater chemistry control, corrosion inhibitor use, alloy selection, and nondestructiveexamination (NDE) methods. Bibliographies have been collected and organized foreach operational issue.

EPRI TR-103824s-V1 R1 Electric Power Research Institute December 1994

The guide includes discussions of the following specific areas: steamgenerator performance history, steam generator design, operational guide-lines to minimize corrosion, steam generator degradation, thermal andhydrodynamic analysis of steam generators, primary water stress corro-sion cracking (PWSCC), tube support and tubesheet corrosion, tubewastage and phosphate secondary water chemistry, tube pitting, tubesupports and tubesheet corrosion (alkaline denting), secondary-sideintergranular attack (IGA) and stress corrosion cracking (SEC), intergran-ular corrosion of alloy 600 from caustic compounds, intergranular corro-sion from acidic compounds, lead cracking of alloy 600, tube corrosionand wear, tube fretting and wear, tube fatigue, water chemistry control,ionic impurity control, water chemistry options, corrosion product control,material selection and alternative designs for steam generators, PWSCCremedies, NDE methods, and major steam generator repairs/replacement.

EPRI PERSPECTIVE The Steam Generator Reference Book, Revision 1documents the state of the art at the time each chapter was written. Theformat of this edition has been revised since publication of the originaldocument so that chapters can be updated as needed and inserted intobinders. EPRI has used the recommendations in this reference book tohelp utility staff implement equipment modifications as well as changes inoperation and maintenance practices. As a result of this work and com-plimentary work by others in the field, the availability of PWR steamgenerators has risen dramatically.

PROJECTRP2858; RP4004Project Managers: J. P. N. PaineNuclear Power GroupEPRI Members: For ordering information about this report, call theEPRI Distribution Center (510) 934-4212.For membership information, call (415) 855-2514.

Steam Generator Reference BookRevision 1

Volume 1

Based onwork sponsored

by

The Steam Generator Owners Groups I and IIThe Steam Generator Reliability Project

andElectric Power Research Institute

J. Peter N. Paine, EditorUlla E. Gustafsson, Associate Editor

December 1994

DISCLAIMER OF WARRANTIES AND LIMITATION OF LIABILITIES

THIS REPORT WAS PREPARED BY THE ORGANIZATION(S) NAMED BELOW AS ANACCOUNT OF WORK SPONSORED OR COSPONSORED BY THE ELECTRIC POWERRESEARCH INSTITUTE, INC. (EPRI). NEITHER EPRI, ANY MEMBER OF EPRI, ANYCOSPONSOR, THE ORGANIZATION(S) NAMED BELOW, NOR ANY PERSON ACTINGON BEHALF OF ANY OF THEM:

(A) MAKES ANY WARRANTY OR REPRESENTATION WHATSOEVER, EXPRESS ORIMPLIED, (I) WITH RESPECT TO THE USE OF ANY INFORMATION, APPARATUS, METHOD,PROCESS, OR SIMILAR ITEM DISCLOSED IN THIS REPORT, INCLUDINGMERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, OR (II) THAT SUCHUSE DOES NOT INFRINGE ON OR INTERFERE WITH PRIVATELY OWNED RIGHTS,INCLUDING ANY PARTY'S INTELLECTUAL PROPERTY, OR {III) THAT THIS REPORT ISSUITABLE TO ANY PARTICULAR USER'S CIRCUMSTANCE; OR

(B) ASSUMES RESPONSIBILITY FOR ANY DAMAGES OR OTHER LIABILITYWHATSOEVER (INCLUDING ANY CONSEQUENTIAL DAMAGES EVEN IF EPRI OR ANYEPRI REPRESENTATIVE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES)RESULTING FROM YOUR SELECTION OR USE OF THIS REPORT OR ANY INFORMATION,APPARATUS, METHOD, PROCESS, OR SIMILAR ITEM DISCLOSED IN THIS REPORT.

ORGANIZATION(S) THAT PREPARED THIS REPORTElectric Power Research Institute

ORDERING INFORMATIONRequests for copies of this report should be directed to the EPRI Distribution Center,207 Coggins Drive P.O. Box 23205, Pleasant Hill, CA94523, (510) 934-4212. Thereis no charge for reports requested by EPRI member utilities and affiliates.

Electric Power Research Institute and EPRI are registered service marks of Electric PowerResearch Institute, Inc.

Copyright 1994 Electric PowerResearch Institute, Inc. All rights reserved.

In Dedication toStanley J. Green

for His Leadership and Serviceto the Steam Generator Project and the Commercial Nuclear Industry

Stanley J. Green served as Director of the Steam Generator OwnersGroups I and II and the Steam Generator Reliability Project from 1979 to1991. Guided by his enthusiasm and leadership, the first Steam GeneratorReference Book was published in 1985.

As manager of steam generator research activities at EPRI, he helpedthe nuclear 'industry increase the reliability of steam generators forpressurized water reactor (PWR) plants. This formidable task involvesidentifying the problems and their causes, providing technical andmanagement leadership to solve the problems, and transferring the resultingtechnology to the electric utilities for implementation.

His contributions to steam generator technology cover a broad spectrumincluding thermal-hydraulics, water chemistry, corrosion, and mechanicalwear. Stanley J. Green provided the leadership, technical advice, andintuitive insight which allowed these diverse technologies to be addressedin an integrated, well-defined manner resulting in significant advances insteam generator design and operation.

Stanley J. Green has earned the highest respect of both the technicaland operational communities associated with PWR steam generatortechnology. Through his efforts the reliability of these costly nuclear powerplant components have been significantly enhanced.

EPRI Licensed Material

ii Steam Generator Reference Book, Revision 1

ACKNOWLEDGMENTSThis book could not have been prepared without significant

professional, technical, and financial contribution from numerousindividuals and companies. In its several revisions, chapters of this bookhave been critically reviewed. The contributions of the following individualsand companies are gratefully acknowledged.

Authors and EPRI Steam Generator Project Office StaffA. K. Agrawal, S. M. Laskowski,Battelle Columbus Division Project ManagerM. J. Angwin, W. H. Layman,Project Manager Director (1977-1979)M. M. Behravesh, D. B. Lowenstein,Manager Dominion Engineering, Inc.W. J. Bilanin, R. G. Lucas,Program Manager Project ManagerR. L. Coit, L. J. Martel,Project Manager Technical Director (1977-1979)G. W. DeYoung, A. R. McIlree,Project Manager Project ManagerJ. A. Gorman, P. Millett,Dominion Engineering, Inc. ManagerS. J. Green, J. A. Mundis,Director (1979-1991) Program ManagerG. Hetsroni, S. Oldberg,Program Manager Project ManagerS. A. Hobart, J. P. N. Paine,Adams & Hobart ManagerB. S. Holmes, M. J. Partridge,Project Manager Dominion Engineering, Inc.E. S. Hunt, W. L. Pearl,Dominion Engineering, Inc. NWTR. L. Jones, C. E. Shoemaker,Director (1991-1993) Project ManagerJ. F. Lang, S. G. Sawochka,Program Manager NWT


Forward iii

G. Sirikantiah,ManagerY. Solomon,Senior Technical AdvisorK. D. Stavropoulos,Dominion Engineering, Inc.D. A. Steininger,ManagerJ. F. Sykes,TU ElectricR. C. Thomas,Project Manager

A. P. L. Turner,Dominion Engineering, Inc.R. G. Varsanik,Project ManagerC. S. Welty, Jr.,Director (1993-)C. L. Williams,Project ManagerC. Wood,Manager

Financial Contributions

Alabama Power CompanyArizona Nuclear Power ProjectArizona Public Service CompanyArkansas Power & Light CompanyBaltimore Gas & Electric CompanyBoston Edison CompanyCarolina Power & Light CompanyCentral Electricity Generating Board (Great Britain)CRIEPI (Japan)Commonwealth Edison CompanyConsolidated Edison CompanyConsumers Power CompanyDuke Power CompanyDuquesne Light CompanyElectrabelElectricite de FranceEntergy OperationsFlorida Power CorporationFlorida Power & Light CompanyGeneral Public UtilitiesGeorgia Power CompanyGPU CorporationHouston Lighting & Power CompanyLong Island Lighting CompanyMaine Yankee Atomic


iv Steam Generator Reference Book, Revision 1

New York Power AuthorityNortheast UtilitiesNorthern States Power CompanyOmaha Public Power DistrictOntario Hydro (Canada)Pacific Gas & Electric CompanyPortland General Electric CompanyPower Authority of the State of New YorkPublic Service Electric & Gas CompanyRochester Gas & Electric CompanySouth Carolina Electric & Gas CompanySouthern California Edison CompanySouthern Nuclear Operating CompanySouth Texas ProjectSpanish UtilitiesSwedish State Power BoardTennessee Valley AuthorityTexas Utilities ElectricVirginia PowerWisconsin Electric Power CompanyWisconsin Public Service CorporationWolf Creek NuclearYankee Atomic

Steam Generator Owners Group I Executive CommitteeW. E. Caldwell, Jr., Chairman (1977-1980), Senior Vice President,Consolidated Edison Company of New York, Inc.B. L. Dow, Jr., Manager, Nuclear Services,Arkansas Power & Light CompanyW. F. Fee, Executive Vice President, Engineering & Construction,Northeast Utilities Service CompanyC. W. Fay, Assistant Vice President,Wisconsin Electric Power CompanyR. Garnsey, Head of Steam Water Chemistry Section,Central Electricity Research Laboratories,Central Electricity Generating Board (CEGB)R. L. Haueter, Director of Special Projects,Consumers Power CompanyJ. G. Holmes, Jr., Assistant Manager of Power Administration,Tennessee Valley Authority


Forward V

W. M. Menger, Chief Consulting Engineer,Houston Lighting & Power CompanyJ. P. Mercier, Director of Studies & Research,Electricite de FranceJ. B. Moore, Vice President,Southern California Edison CompanyD. M. Noble, Director of Operating Services,Consumers Power CompanyW. L. Riedel, Principal Chemist,Baltimore Gas & Electric CompanyL. Rylander, Department Manager,Swedish State Power BoardP. F. Santoro, Chief, Generation Mechanical Systems Engineering,Northeast Utilities Service CompanyA. D. Schmidt, Chairman (1980-1982), Vice Chairman (1977-1980),Vice President, Power Resources,Florida Power & Light CompanyG. J. Schnabel, Consulting Mechanical Engineer,Public Service Electric & Gas Company of New JerseyD. R. Sikes, Director, Fossil Operations,Arkansas Power & Light CompanyR. A. Thomas, Vice President,Southern Company Services, Inc.L. D. White, Vice Chairman (1980-1982), Executive Vice President,Operations & Engineering,Rochester Gas & Electric CorporationA. W. Wofford, Vice President,Long Island Lighting Company

Steam Generator Owners Group I Member RepresentativesJ. P. Bayne, Senior Vice President, Nuclear Generation,Power Authority of the State of New YorkG. E. Brobst, General Supervisor, Chemistry,Baltimore Gas & Electric CompanyD. A. Bryant, Project Engineer,Boston Edison Company


vi Steam Generator Reference Book, Revision 1

S. Burstein, Executive Vice President,Wisconsin Electric Power CompanyW. E. Caldwell, Jr., Senior Vice President,Consolidated Edison Company of New York, Inc.W. G. Counsil, Senior Vice President, Nucl. Engineering & Operations,Northeast Utilities Service CompanyJ. D. Deress, Project Engineering Manager,Commonwealth Edison CompanyR. B. DeWitt, Vice President, Nuclear Operations,Consumers Power CompanyR. Dietch, Vice President, Nuclear,Southern California Edison CompanyP. Fontaine, Adjoint au Chef,Electricite de FranceR. Garnsey, Head of Steam Water Chemistry Section,Central Electricity Research Laboratories,Central Electricity Generating BoardJ. W. Griffin, Assistant Vice President,Arkansas Power & Light CompanyR. L. Haueter, Director of Special Projects,Consumers Power CompanyJ. G. Holmes, Jr., Assistant Manager of Power Administration,Tennessee Valley AuthorityT. Kurosawa, Manager, Reactor Chemistry Department,Energy & Environment Laborator~CRIEPI, JapanR. L. Mansfield, Junior Plant Engineer,Georgia Power CompanyE. R. McGrath, Senior Vice President, Power Generation,Consolidated Edison Company of New YorkW. M. Menger, Chief Consulting Engineer,Houston Lighting & Power CompanyJ. P. Mercier, Chef du Department Material,Electricite de FranceJ. B. Moore, Vice President,Southern California Edison Company


B. Nilsson, Chief Engineer,Swedish State Power BoardW. O. Parker, Vice President, Steam Production,Duke Power CompanyW. L. Riedel, Principal Chemist,Baltimore Gas & Electric CompanyA. D. Schmidt, Executive Vice President, Power Resources,Florida Power & Light CompanyJ. Schmieder, Executive Vice President and Chief Engineer,Power Authority of the State of New YorkG. J. Schnabel, Consulting Mechanical Engineer,Public Service Electric & Gas CompanyD. R. Sikes, Director, Fossil Operations,Arkansas Power & Light CompanyH. Takenouchi, Director, Energy & Environment Laboratory,CRIEPI, JapanR. A. Thomas, Vice President,Southern Company ServicesJ. A. Tiernan, Manager, Nuclear Power Department,Baltimore Gas & Electric CompanyE. E. Utley, Executive Vice President,Carolina Power & Light CompanyE. E. Van Brunt, Jr., Vice President, Construction Projects,Arizona Public Service CompanyH. P. Walker, Assistant Plant Manager, Vogtle,Georgia Power CompanyL. D. White, Jr., Executive Vice President,Rochester Gas & Electric CorporationB. D. Withers, Vice President, Nuclear,Portland General Electric CompanyA. W. Wofford, Vice President,Long Island Lighting CompanyM. G. Zaalouk, Head of Nuclear Engineering Division,Houston Lighting & Power Company

Forward vii


viii Steam Generator Reference Book, Revision 1

Steam Generator Owners Group I Technical Advisory Committee

R. J. Acosta, Plant Support Section Supervisor,Florida Power & Light CompanyO. Batum, Vice Chairman (1977-1980), Manager,Nuclear Safety & Licensing Department,Southern Company ServicesM. A. Bell, Supervising Mechanical Engineer,Portland General Electric CompanyJ. P. Berge, Chef du Groupe des Laboratories,Electricite de FranceJ. C. Blomgren, Project Manager,Commonwealth Edison CompanyG. E. Brobst, General Supervisor, Chemistry,Baltimore Gas & Electric CompanyD. J. Clowers, Licensing Engineer,Georgia Power CompanyA. E. Curtis, III, Manager, Materials Engineering Division,Rochester Gas & Electric CorporationA. de Montardy, Head, Heat Transfer & Aerodynamics Department,Electricite de FranceJ. Engstrom, Senior Mechanical Engineer,Swedish State Power BoardJ. M. Fackelmann, Supervisor, Nuclear Materials & Chemistry,Northeast Utilities Services CompanyG. D. Frieling, Senior Project Engineer,Wisconsin Electric Power CompanyR. Garnsey, Head of Steam Water Chemistry Section,Central Electricity Research Laboratory,Central Electricity Generating Board (CEGB)D. Goetcheus, Supervisor of Metallurgical Analysis,Tennessee Valley AuthorityR. L. Goyette, Manager, Systems Operations,Power Authority of the State of New YorkW. A. Haller, Manager, Technical & Environmental Services,Duke Power CompanyR. L. Haueter, Chairman (1977-1980), Director of Special Projects,Consumers Power Company


Forward ix

C. B. Hardee, Mechanical Equipment Specialist,Carolina Power & Light CompanyW. Harrison, Lead Engineer, Nuclear Engineering Department,Houston Lighting & Power CompanyJ. Kieffer, Service de la Production Thermique,Electricite de FranceT. Kurosawa, Manager, Reactor Chemistry Department,Energy & Environment Laboratory,CRIEPI, JapanR. Lane, Manager, Mechanical Engineering,Arkansas Power & Light CompanyH. Mahlman, Principal Chemical Engineer,Tennessee Valley AuthorityR. E. Millard, Supervisor, Steam Generation Chemistry,Southern California Edison CompanyD. M. Noble, Chairman (1980-1982), Plant Superintendent,Consumers Power CompanyH. N. Paduano, Section Supervisor,Florida Power & Light CompanyA. B. Poole, Senior Nuclear Systems Engineer,Houston Lighting & Power CompanyG. A. Reed, Manager, Nuclear Power Division,Wisconsin Electric Power CompanyA. C. Rogers, Nuclear Engineering Supervisor,Arizona Nuclear Power ProjectS. Rothstein, Consulting Engineer,Consolidated Edison Company of New YorkP. F. Santoro, Chief, Generation Systems Mechanical Engineering,Northeast Utilities Service CompanyJ. R. Schepers, Senior Engineer,Consumers Power CompanyJ. Schmieder, Executive Vice President & Chief Engineer,Power Authority of the State of New YorkD. G. Slear, Senior Engineer,GPU Service CorporationG. Slifer, Chemical Plant Engineer,Public Service Electric & Gas Company


x Steam Generator Reference Book, Revision 1

A. L. Sudduth, Design Engineer,Duke Power CompanyH. P. Walker, Assistant Plant Manager, Vogtle,Georgia Power CompanyW. Way,Carolina Power & Light CompanyB. D. Withers, Vice President, Nuclear,Portland General Electric Company1. S. Woolsey, Central Electricity Research Laboratory,Central Electricity Generating Board (CEGB)A. W. Zeuthen, Metallurgical & Welding Engineer,Long Island Lighting Company

Steam Generator Owners Group II Executive CommitteeJ. C. Blomgren, Manager, Steam Generator ProgramCommonwealth Edison CompanyD. W. Cockfield, Vice President, Nuclear DivisionPortland General ElectricB. L. Dow, Jr., Manager, Nuclear Services,Arkansas Power & Light CompanyL. R. Eliason, General Manager, Nuclear Plants,Northern States PowerC. W. Fay, Vice President, Nuclear Power,Wisconsin Electric Power CompanyR. Garnsey, Manager, R&D, Sizewell"B" Power Station,Central Electricity Generating BoardW. A. Haller, Manager, Technical & Environmental Services,Duke Power CompanyW. Josiger, Manager, Special Projects,New York Power AuthorityR. P. McDonald, Senior Vice President, Nuclear Generation,Alabama Power CompanyJ.- P. Mercier, Chef, Department Materiel,Electricite de FranceJ. A. Mundis, Supervisor, Nuclear Services,Southern California Edison Company


Forward xi

L. Rylander, Department Manager,Swedish State Power Boardp. F. Santo~o, Director, Generation Projects,Northeast Utilities Service CompanyJ. W. Williams, Jr., Group Vice President, Nuclear Energy,Florida Power & Light CompanyB. D. Withers, President & Chief Executive Officer,Wolf Creek Nuclear Operating Corporation

Steam Generator Owners Group II Member RepresentativesR. P. McDonald, Senior Vice President, Nuclear Generation,Alabama Power CompanyS. H. Steinhart, Assistant Division Manager, Mechanical Engineering,American Electric Power Services CorporationR. M. Butler, Director, Technical Services,Arizona Public Service CompanyJ. Vorees, Manager, Nuclear Operations,Arizona Public Service CompanyB. Dow, Manager, Nuclear Services,Arkansas Power & Light CompanyS. McGregor, Arkansas Nuclear One,Arkansas Power & Light CompanyJ. A. Tiernan, Vice President, Nuclear Energy,Baltimore Gas & Electric CompanyG. P. Beatty, Jr., Manager, Special Projects,Carolina Power & Light CompanyA. B. Cutter, Vice President, Nuclear Engineering & Licensing,Carolina Power & Light CompanyR. Garnsey, Manager, R&D, Sizewell B Power Station,Central Electricity Generating Board (CEGB)J. M. Zamarron, Jefe Ing. Y Suministros,Central Nuclear de Almaraz, SpainF. Alomar, Engineering Manager,Central Nuclear de Asco, SpainT. Mizuno, Director & General Manager, NPD, R&D Headquarters,CRIEPI, Japan


xii Steam Generator Reference Book, Revision 1

M. Yasuda, Deputy General Director,CRIEPI, JapanJ. D. Deress, Project Engineering Manager,Commonwealth Edison CompanyE. R. McGrath, Executive Vice President, Power Generation,Consolidated Edison Company of New York, Inc.M. Selman, Vice President, Nuclear Power,Consolidated Edison Company of N.Y., Inc.J. Schepers, Superintendent, Chemistry & Radwaste,Consumers Power CompanyW. A. Haller, Manager, Technical & Environmental Services,Duke Power CompanyJ.- P. Mercier, Chef, Dept. Materiel,Electricite de FranceR Dierkens,Manage~ElectronucleaireD. Borgese, Director,ENEL-CRTN ENELJ. W. Williams, Jr., Group Vice President, Nuclear Energy,Florida Power & Light CompanyR A. Cremades, Jefe de la Div. de Ingenieria y Equipos,Fuerzas Electricas De Cataluna FecsaC. D. Pugh, Senior Plant Engineer,Georgia Power CompanyD. K. Croneberger, Director, Engineering & Design,GPU Nuclear CorporationS. M. Dew, Deputy Project Manager,Houston Lighting & Power CompanyJ. Evans, Vice President, Power Supply Operations,Kansas City Power & Light CompanyD. T. McPhee, Senior Vice President, Systems Power Operations,Kansas City Power & Light CompanyC. J. Ross, Senior Director, Nuclear Affairs,Kansas City Power & Light CompanyG. L. Koester, Vice President, Nuclear,Kansas Gas & Electric Company

EPHI Licensed Material

Forward xiii

D. E. Adams, III, Utility Engineer,Louisiana Power & Light CompanyK. R . Iyengar, Nuclear Support Manager,Louisiana Power & Light CompanyW. Josiger, Resident Manager,New York Power AuthorityG. D. Baston, Director, Nuclear Engineering & Operations Services,Northeast Utilities Service CompanyP. F. Santoro, Director, Generation Projects,Northeast Utilities Service CompanyL. R. Eliason, General Manager, Nuclear Plants,Northern States Power CompanyR. Andrews, Division Manager, Nuclear Production,Omaha Public PowerR. L. Andrews, Division Manager, Nuclear Production,Omaha Public Power DistrictT. J. McIvor, Supervisor, Technical,Omaha Public Power DistrictJ. D. Shiffer, Vice President, Nuclear Power Generation,Pacific Gas & Electric CompanyD. W. Cockfield, Vice President, Nuclear Division,Portland General Electric CompanyJ. T. Boettger, Assistant Vice President, Nuclear Operations Support,Public Service Electric & Gas CompanyD. J. Jagt, Assistant General Manager, Project Engineering,Public Service Electric & Gas CompanyP. R. H. Landrieu, Vice President, Engineering & Construction,Public Service Electric & Gas CompanyT. J. Martin, Vice President, Nuclear Generation,Public Service Electric & Gas CompanyJ. E. Maier, Senior Vice President, Operations & Engineering,Rochester Gas & Electric CorporationR. E. Smith, Chief Engineer,Rochester Gas & Electric CorporationR. J. Rodriguez, Assistant General Manager, Nuclear,Sacramento Municipal Utility District


xiv Steam Generator Reference Book, Revision 1

O. W. Dixon, Jr., Vice President, Nuclear Operations,South Carolina Electric & Gas CompanyD. A. Nauman, Vice President, Nuclear Operations,South Carolina Electric & Gas CompanyK. P. Baskin, Vice President,Southern California Edison CompanyJ. A. Mundis, Supervisor, Nuclear Services,Southern California Edison CompanyL. B. Long, Manager, Nuclear Safety & Licensing,Southern Company Services, Inc.J. L. Hunyadi, Ing., Project Manager, Thermal Power,Swedish State Power BoardL. Rylander, Department Manager,Swedish State Power BoardN. A. Petrick, Executive Director,SNUPPSH. Abercombie, Nuclear Power Division,Tennessee Valley AuthorityT. Ziegler, Division of Nuclear Power,Tennessee Valley AuthorityJ. C.Kuykendall, Vice President,Texas Utilities Generating CompanyD. F. Schnell, Vice President, Nuclear,Union ~lectricCompanyP. Blanc,Union Electrica, Fenosa, SAR. M. Taylor, Nuclear Technical Services,Virginia Electric & Power CompanyJ. W. Ogren, Director, Operations & Maintenance Support,Virginia Power CompanyW. A. Thornton, Supervisor, Systems Chemistry, Nuclear Operations,Virginia Power CompanyC. W. Fay, Vice President, Nuclear Power,Wisconsin Electric Power CompanyB. D. Withers, President & CEO,Wolf Creek Nuclear Operating Corporation


Forward xv

Steam Generator Owners Group II Technical Advisory Committee

R. J. Acosta, Supervisor, Nuclear Energy Section,Florida Power & Light CompanyD. E. Adams, III, Chemistry Unit Coordinator,Louisiana Power & Light CompanyG. P. Airey, Sizewell "B" Project,Central Electricity Generating BoardB. Allen, Chemistry Department, Waterford Nuclear Plant,Louisiana Power & Light CompanyJ. A. Bailey, Manager, Mechanical Engineering,Kansas Gas & ElectricP. A. Bauer, Project Engineer, Nuclear, Staff Support,Carolina Power & Light CompanyJ. P Berge, Chef du Groupe des Laboratoires,Electricite de FranceG. J. Bignold, Steam Water Chemistry Section,Central Electricity Generating BoardP. Blanc,Union Electrica, Fenosa, SAJ. C. Blomgren, Manager, Steam Generator Program,Commonwealth Edison CompanyD. Borgese, Director,ENEL-CRTNR. F. Brandt, Nuclear Plant Services Engineering,Public Service Electric & Gas CompanyD. W. Braswell, Superintendent, Engineering,Comanche Peak Station,Texas Utilities Generating CompanyF. Brejani,Ente Nazionale per l'Energia ElettricaA. Buford,Arkansas Power & Light CompanyG. R. Capodanno, Director, Fluid Systems,GPU Nuclear CorporationW. C. Carr, Supervisor, Chemistry & Environment,Alabama Power Company


xvi Steam Generator Reference Book, Revision 1

J. O. Cermak, Technical Director,SNUPPSS. B. Clay, Engineer, Nuclear Generation,Pacific Gas & Electric CompanyF. D. Crawford, Director, Nuclear Power,Kansas City Power & Light CompanyF. Alomar Cremades, Jefe de la Div. de Ingenieria y Equipos,Fuerzas Electricas De Cataluna FecaP. T. Crinigan, General Supervisor, Chemistry,Baltimore Gas & Electric CompanyB. G. Croley, Group Manager, Technical Support,South Carolina Electric & GasA. E. Curtis, III, Manager, Materials Engineering Division,Rochester Gas & Electric CorporationJ. P. DeRoy, Engineer, Nuclear Operations,New York Power AuthorityP. M. Egebrecht, PVNGS Nuclear Chemist,Arizona Public Service CompanyJ. Engstrom, Senior Engineer,Swedish State Power BoardJ. M. Fackelmann, Supervisor, Nuclear Materials & Chemistry,Northeast Utilities Service CompanyJ. J. Field, Superintendent, Technical Support,Sacramento Municipal Utility DistrictG. Frederick, Manager, Nuclear Equipment,ElectronucleaireG. D. Frieling, Superintendent, Systems Engineering,Wisconsin Electric Power CompanyJ. A. Gabrielson, Engineering Staff Specialist, South Texas Project,Houston Lighting & Power CompanyR. Garnsey, Manager, R&D, Sizewell "B "Power Station,Central Electricity Generating Board (CEGB)D. F. Goetcheus, Supervisor, Metallurgical Analysis Section,Tennessee Valley AuthorityA. P. Graham, Nuclear Systems Engineering,Public Service Electric & Gas Company


Forward xvii

D. R. Hafer, Assistant Manager, Heat Exchangers & Pumps Section,American Electric Power Service CorporationW. G. Hairston, III, Manager, Nuclear Engineering & Technical Support,Alabama Power CompanyW. A. Haller, Manager, Technical & Environmental Services,Duke Power CompanyC. B. Hardee, Project Engineer, Special Projects,Carolina Power & Light CompanyJ. L. Harness, Manager, Nuclear Staff Support,Carolina Power & LightC. T. Hillman, Palisades Nuclear Plant,Consumers Power CompanyN. Hoadley, Lead Engineer, Wolf Creek Generating Station,Kansas Gas & Electric CompanyJ. Johnston, Plant Maintenance,Northern States Power CompanyR. D. Lane, Manager, Mechanical Engineering, Arkansas Nuclear One,Arkansas Power & Light CompanyR. Lawson, Steam Generator Coordinator,Arkansas Power & Light CompanyS. D. Lee, Plant Vogtle,Georgia Power CompanyL. B. Long, Manager, Nuclear Safety & Licensing,Southern Company ServicesH. Mahlman, Staff Specialist, Engineering Design Division,Tennessee Valley AuthorityR. L. Mansfield, Junior Plant Engineer,Georgia Power CompanyA. L. Matheny, Steam Generator Engineer,Southern California Edison CompanyS. McGregor, Arkansas Nuclear One,Arkansas Power & Light CompanyT. McIvor, Supervisor, Ft. Calhoun Unit 1,Omaha Public Power DistrictT. Mizuno, Director, General Manager, NPD, R&D Headquarters,CRIEPI, Japan


xviii Steam Generator Reference Book, Revision 1

J. E. Moaba, Section Supervisor, Materials, Codes & Inspection,Florida Power & Light CompanyN. Nilsen, Engineer, Special Projects, Nuclear Engineering,New York Power AuthorityJ. W. Ogren, Director, Operations & Maintenance Support,Virginia Power CompanyW. S. Orser, General Manager, Technical Functions,Portland General Electric CompanyR. Pascali, Senior Research Engineer,Ente Nazionale per L'Energia ElectricaA. C. Passwater, Superintendent, Licensing,Union Electric CompanyT. L. Patterson, Manager, Technical Support,Omaha Public Power DistrictR. P. Pearson, Production Engineer, Prairie Island,Northern States Power CompanyA. Bruce Poole, Senior Nuclear Systems Engineer,Houston Lighting & Power CompanyL. Pope, Comanche PeakTexas Utilities Generating CompanyC. David Pugh, Senior Plant Engineer, Vogtle Electric Generating Plant,Georgia Power CompanyD. A. Rickett, Senior Engineer,Southern California Edison CompanyS. Rothstein, Chemical & Metallurgical Engineer,Consolidated Edison Company of N.Y., Inc.G. C. Russell, Nuclear Generation Engineer,Pacific Gas & Electric CompanyP. Saint-Paul, Department Etudes de Materiaux,Electricite de FranceG. J. Schnabel, Consulting Mechanical Engineer,Public Service Electric & Gas CompanyF. Schwoerer, Technical Director,SNUPPSV. J. Shanks, Superintendent, Chemistry,Union Electric Company


Forward xix

A. L. Sudduth, Design Engineer, M&N Division,Duke Power CompanyR. M. Taylor, Nuclear Technical Services,Virginia Electric & Power CompanyW. A. Thornton, Nuclear Operations Support,Virginia Electric & Power CompanyP. E. Troy,South Carolina Electric & Gas CompanyJ. H. Uhl, Plant Mechanical Engineer,Sacramento Municipal Utility DistrictJ. J. Villa,Central Nuclear de TrilloH. P. Walker, Assistant Plant Manager, Vogtle Electric Generating Plant,Georgia Power CompanyR. P. Wendling, Manager, Mechanical Engineering,Union Electric CompanyC. P. Yundt, General Manager, Technical Functions, Nuclear Division,Portland General Electric Company

Steam Generator Reliability Project Executive GroupG. D. Baston, Director, Nuclear Engineering & Operations,Northeast UtilitiesW. Conway, Executive Vice President,Arizona Public ServiceD. K. Croneberger, Director, Engineering,GPU NuclearR. P. McDonald, President,Southern Nuclear Operating CompanyS. Rosen, Vice President,Houston Lighting & Power CompanyD. F. Schnell, Vice President, Nuclear,Union Electric CompanyM. Selman, Senior Vice President,Consolidated Edison of NY, Inc.J. L. Skolds, Vice President, Nuclear Operations,South Carolina Electric & Gas


xx Steam Generator Reference Book, Revision 1

R. E. Smith, Senior Vice President, Production & Engineering,Rochester Gas & Electric CorporationM. Tuckman, Senior Vice President,Duke Power CompanyB. D. Withers, President & Chief Executive Officer,Wolf Creek Nuclear Operating CorporationJ. D. Woodard, Vice President, Nuclear,Southern Nuclear Operating CompanyJ. J. Zach, Senior Manager, Nuclear Engineering,Wisconsin Electric Power Company

Steam Generator Reliability Project Member Representatives.M. F. Hodge, Mechanical/Chemical Engineering Manager,Arizona Public Service CompanyE. C. Sterling, Manager, Nuclear Engineering Production,Arizona Public Service CompanyR. Lane,Arkansas Power & Light CompanyJ. Lozano,Asociacion Nuclear De Asco, SpainR. E. Denton, Manager,Baltimore Gas & Electric CompanyR. B. Richey, Vice President,Carolina Power & Light CompanyG. Vaughn, Vice President,Carolina Power & Light CompanyJ. M. Zamarron,Central Nuclear de Almaraz, SpainJ. C. Blomgren, Manager, Steam Generator Program,Commonwealth Edison CompanyC. J. Durkin, Jr.,Consolidated Edison Company of N.Y.,R. P. Noberini, Manager, Technology Transfer R&D,Consolidated Edison Company of N.Y., Inc.H. Hirano,CRIEPI, Japan


Forward xxi

H. Takaku, Manager, Mechanical Engineering Section,CRIEPI, JapanW. A. Haller, Manager, Nuclear Technical Services,Duke Power CompanyJ. D. Sieber, Vice President, Nuclear Group,Duquesne Light CompanyJ. P. Berge, Controleur General Adjoint,Electricite de FranceJ.-P. Hutin, NSSS Division Manager,Electricite de FranceG. Frederick, Manager, Nuclear Generation Department,ElectronucleaireR. C. Widell, Director, Nuclear Operations,Florida Power CorporationW. H. Bohlke, Vice President, Nuclear Engineering & Licensing,Florida Power & Light CompanyK. R. Craig, Nuclear Energy Division,Florida Power & Light CompanyC. K. McCoy, Vice President,Georgia Power CompanyB. D. Elam, Jr., Director, Components & Structures,GPU Nuclear CorporationS. Rosen, Vice PresidentHouston Lighting & Power CompanyD. E. Baker, Manager, Nuclear Operations Support & Assessment,Louisiana Power & Light CompanyD. Sturniolo, Principal Radiological Engineer,Maine Yankee Atomic Power CompanyW. A. Josiger, Resident Manager, Nuclear Operations,New York Power AuthorityG. D. Baston, Director, Nuclear Engineering & Operations,Northeast Utilities Service CompanyE. Watzl, General Manager, Prairie Island,Northern States Power CompanyG. P. Airey, Sizewell "B" Project Management Team,Nuclear Electric


xxii Steam Generator Reference Book, Revision 1

R. Garnsey, Manager, Safety & Technology,Nuclear ElectricS. K. Gambhir,Omaha Public Power DistrictJ. Brown, Manager, Metallurgical Research DepartmentOntario HydroJ. A. Hayes, Supervisor, RECE,Pacific Gas & Electric CompanyL. F. Womack, Manager, Engineering,Pacific Gas & Electric CompanyC. P. Yundt, Trojan Nuclear Plant,Portland General Electric CompanyH. Berrick,Public Service Electric & Gas CompanyR. E. Smith, Senior Vice President, Production & Engineering,Rochester Gas & Electric CorporationD. Moore,South Carolina Electric & Gas CompanyJ. L. Skolds, Vice President, Nuclear Operations,South Carolina Electric & Gas CompanyR. P. McDonald, Jr., President,Southern Nuclear Operating CompanyJ. D. Woodard, Vice President,Southern Nuclear Operating CompanyK. Persson, Manager, Ringhalsverket 3 & 4,Swedish State Power BoardN. C. Kazanas, Vice President, Operations Servi.ces,Tennessee Valley AuthorityD. R. Keuter,Tennessee Valley AuthorityE. Matranga,Toledo Edison CompanyM. R. Blevins, Manager, Nuclear Operations Support,TV ElectricD. F. Schnell, Vice President, Nuclear,Union Electric Company


Forward xxiii

J. J. Zach, Senior Manager, Nuclear Engineering,Wisconsin Electric Power CompanyM. L. Marchi, Plant Manager,Wisconsin Public Service CorporationB. D. Withers, President & Chief Executive Officer,Wolf Creek Nuclear Operating Corporation

Steam Generator Reliability Project Technical Advisory GroupJ. D. Abramovici, HjX & PV Manager,GPU Nuclear CorporationR. Affolter, Supervisor, Systems Engineering,Union Electric CompanyG. P. Airey, Sizewell fiB" Project Management Team,Nuclear ElectricR. L. Baker, Consulting Engineer,Houston Lighting & Power CompanyJ. C. Blomgren, Manager, Steam Generator Program,Commonwealth Edison CompanyG. J. Bollini, PISGV Project Manager,Spanish UtilitiesP. Brown,Yankee AtomicJ. M. Cate, Engineer, Special Services,Omaha Public Power DistrictK. R. Craig, Nuclear Energy Division,Florida Power & Light Company:r T. Crinigan, Nuclear Energy Division,Baltimore Gas & Electric CompanyM. R. Danak, Senior Staff Engineer,Public Service Electric & GasR. J. Dolansky, Nuclear Generation Department,New York Power AuthorityR. W. Eaker, Technical Systems Manager II, Chemistry,Duke Power CompanyJ. Engstrom, Senior Engineer,Swedish State Power Board


xxiv Steam Generator Reference Book, Revision 1

J. M. Fackelmann, Principal Engineer,Northeast UtilitiesJ. S. Frick, Supervisor, Special Projects & Performance Engineering,South Carolina Electric & Gas CompanyG. D. Frieling, Manager, Nuclear Engineering,Wisconsin Electric Power CompanyJ. K. Gillen, General Supervisor, Chemistry,New York Power AuthorityD. F. Goetcheus, Maintenance Manager, NSS/SG,Tennessee Valley AuthorityD. J. Hampshire, Steam Generator Technical Coordinator,Pacific Gas & Electric CompanyD. F. Harrison, Senior Engineer,Entergy Operations, Inc.P. Hernalsteen, Director, Mechanical Division,LaborelecJ. W. Hoss, Senior Engineer, Results Engineering,TU ElectricL. D. Hughes, Supervisor, Primary Systems Engineering,Toledo Edison CompanyG. A. Kammerdeiner, Director, Materials & Standards Engineering,Duquesne Light CompanyM. L. Layton, Support Engineer, Chemistry/Radiochemistry,Louisiana Power & Light CompanyR. Lewis, Supervisor, Results Engineering,Wolf Creek Nuclear Operating CorporationP. C. Lichtenberger, Supervising Scientist, Corr. & Tri. Technical Section,Ontario HydroA. L. Matheny, Steam Generator Engineer,Southern California Edison CompanyE. Matranga,Toledo Edison CompanyJ. A. "Buzz" Miller,Alabama Power CompanyK. Neese, Steam Generator Project Engineer,Portland General Electric ~ompany

EPRJ Licensed Material

Forward xxv

N. Nilsen, Senior Engineer,New York Power AuthorityF. Nordmann, Associate Manager, Chemistry,Electricite de FranceR. P Pearson, Superintendent, Steam Generator Systems,Northern States Power CompanyC. T. Polidoroff, Senior Nuclear Generation Engineer,Pacific Gas & Electric CompanyP Skulte, Metallurgical Engineer,Consolidated Edison Company of N.Y., Inc.J. F. Smith, Manager, Materials Engineering & Inspection Services,Rochester Gas & Electric CorporationC. S. Smoker, Supervisor, Plant Quality Programs,Wisconsin Public Service CorporationP. Spekkens, Section Head, Corrosion Chemistry,Ontario HydroD. Sturniolo, Principal Radiological Engineer,Maine Yankee Atomic Power CompanyK. Sweeney,Arizona Public Service CompanyH. Takamatsu, Manager, SG Project, Nuclear Power Operations Dept.,CRIEPI, JapanR. H. Thompson, Nuclear Results Specialist,Florida Power CorporationG. Vaughn, Vice President,Carolina Power & Light CompanyI. S. Woolsey,Nuclear Electric

The Electric Power Research Institute and my colleagues there haveprovided administrative and intellectual support in bringing this effort tocompletion. The support and guidance provided by John J. Taylor, RobinL. Jones, and Charles S. Welty have been invaluable.

J. Peter N. PainePalo Alto, CaliforniaDecember 1994

EPHI Licensed Material

PREFACE

Operation and maintenance of PWR Steam Generators with highavailability are among the most difficult challenges that face owners. Inresponse to corrosion-related difficulties causing increased O&M costs, agroup of utilities, owning or planning PWR nuclear power plants, formedthe Steam Generator Owners Group in 1977. The purpose of this groupwas to sponsor a concerted effort to find solutions to these steam generatoroperating concerns.

The Owners Group asked EPR! to manage the technical program. InMarch 1977, EPRI established the Steam Generator Project Office in EPRI'sNuclear Power Division. On July 26, 1977, the Owners Group met in Chicagoto adopt a draft charter and to elect an executive committee. Initial1~ twenty-one utilities joined the Steam Generator Owners Group and committed over$30 million to support the program. Other utilities later became membersresulting in a total contribution of $36 million. In parallel, EPRI supportedsteam generator studies at about $2.5 million per year. This work wascoordinated with the program sponsored by the Steam Generator OwnersGroup.

Subsequently, because of continued challenges that emerged while thisprogram was underway, a new group, called Steam Generator OwnersGroup II, was formed in 1983 to address these new issues over the period1983-1986. Ultimately, the utility membership increased to 37, providing$29 million in support of the program. In parallel, the total EPR! support ofthe Owners Group programs over the period 1977 to 1986 was about$26 million.



The Steam Generator Owners Group II was successfully completed.However, additional causes of steam generator unavailability continued toarise and a new major project, called the Steam Generator Reliability Project,completely funded by EPRI at a level of $30 million, was formed to operateover the period 1987-1992. In addition to the U. S. members, seveninternational utilities have participated in the Steam Generator ReliabilityProject under technical exchange agreements.

The results of the programs have been transmitted to Steam GeneratorOwners Groups I and II and to members of the Steam Generator ReliabilityProject as described below.

Final Reports of Individual ContractsFinal reports of more than 175 individual contracts resulting from the

Steam Generator Owners Group I (SGOG I) efforts have been issued. Thesereports were listed and summarized in one document entitled SteamGenerator Program Summary dated March 31, 1983. Similarly, the results ofmore than 225 individual contracts resulting from the Steam GeneratorOwners Group II (SGOG II) effort have been issued. These reports aresummarized in the Steam Generator Program Summary dated April 1989. TheSteam Generator Reliability Project (SGRP) effort is still underway and anumber of final reports have been issued. The progress of this effort isreported periodically in Status of Steam Generator Contracts. The last statusreport is dated October 1991.

Technology Transfer PackagesIn 1983, a set of technology transfer packages were prepared and

distributed to the members. Each information package contained fourvideotapes, seven executive summaries, seven technical summaries, andseven slide presentations. The objective was to transmit the results of theprogram as effectively as possible both to the utility management and thestaff.

Design and Operation Guidelines to Minimize Steam GeneratorCorrosion

Through the joint efforts of SGOG Advisory Committees and the SteamGenerator Project Office, 14 Design and Operation Guidelines were preparedand issued during 1980-1983. These guidelines were based on the resultsof SGOG research programs and utility, architect/engineer, and vendorexperiences as reported in the literature and at industry meetings. InDecember 1986, they were updated and consolidated into a two volume set


Preface iii

of Plant Design and Modifications Guidelines and one volume of Plant andSteam Generator Operation Guidelines. Also, two guidelines on the Designand Operation for Makeup Water Treatment System were issued at the sametime.

Two additional major guidelines have been issued and are being usedextensively by the industry. Revision 0 of the PWR Secondary Water ChemistryGuidelines was published in 1982. Revision 1 was issued in 1985 and Revision2 in 1988. The other, the PWR Steam Generator Examination Guidelines, wasissued informally for the utility community in early 1980. The originalversion was issued in 1981 and revised in 1984. In 1988, Revision 2 of theseguidelines was issued as an EPRI report.

Steam Generator Reference BookThe original version of this book was based primarily on work

sponsored by the first Steam Generator Owners Group, but it also includedwork funded by EPRI, pertinent literature, and experiences of the electricutility industry. It documented the state-of-the-art in PWR steam generatortechnology at that time and provided a ready reference for operators,owners, and designers of PWR nuclear power plants. The Reference Bookwas intended for use with the Design and Operation Guidelines describedabove.

This Revision 1 of the Reference Book updates the original version byincluding the results of research completed since the issuance of the book.It includes work completed under Steam Generator Owners Group II andmuch of the work completed under the Steam Generator Reliability Project.The format of the book has been revised so that individual chapters can beupdated as necessary in the future.

The purpose of the original and Revision 1 of the Reference Book is tointegrate the results of research contracts and other available informationinto a format that can be easily used by the utility industry. In addition, theReference Book summarizes options and recommendations for improvingthe expected operating life of PWR steam generators. The options will beutility specific and will depend on such factors as the age of the plant,design/construction; plant siting, utility policies, etc. (Most of theserecommendations are described in detail in the Design and OperationGuidelines.)

Chapter 1 briefly describes the PWR steam generator and provides thebackground that led to the formation of the original Steam GeneratorOwners Group and the subsequent programs.

Chapter 2 reviews the history of PWR steam generator performance. Itincludes a description of a typical PWR power plant and how the design



has evolved in 20 years. This chapter also contains a discussion of theproblems that have occurred in those steam generators.

Chapter 3 provides the bases and objectives of Steam Generator OwnersGroups I and II and the Steam Generator Reliability Project. The researchfindings are summarized and several field applications are described.

Chapter 4 provides recommendations and options generated by SteamGenerator Owners Group programs and other work. The general areascovered include chemistry control, plant operation, balance of plant design,and steam generator design. The Design and Operation Guidelines aresummarized.

Chapters 5 through 19 address each of the known and anticipated steamgenerator challenges and the factors affecting them. The relative importanceof each factor is included in the discussion, as well as, where possible, theuncertainties of those judgments. The specific causes of steam generatorunavailability are identified so that corrective actions may be focused.

Chapters 20 through 27 discuss possible actions to minimize theproblems listed in Chapter 2. The benefits and risks of each of these actionsare documented. Where these actions have been implemented, the resultsare discussed.

Appendix A includes a listing of final reports by contract number andby final report number. Appendix B details plant characteristics of PWRsteam generators worldwide.


CONTENTS

1 Introduction 1-1PWR Steam Generators 1-2

Background 1-3

References 1-9

2 Steam Generator Performance History 2-1Introduction 2-2

Pressurized Water Reactor (PWR) Power Plant Description 2-2Steam Generators 2-3

Recirculating Steam Generators 2-4Once-Through Steam Generators (OTSGs) 2-11

Steam Generator Fabrication 2-14Balance-of-Plant Systems 2-15

Condensers 2-18Condensate System 2-19Condensate Polishing System 2-19Feed System 2-19Drain System 2-19Blowdown Processing System 2-20Makeup Water System 2-20Moisture Separator Drain Routing 2-23

Operating Plant Performance Problems 2-23

References 2-34



3 Steam Generator Programs 3-1Introduction 3-2

Steam Generator Owners Group I 3-2Background 3-2Technical Program 3-3

Subprogram 0801: Quality NondestructiveExamination Techniques 3-5

Subprogram 0802: Evaluation of On-OrderSteam Generator Designs 3-6

Subprogram 0803: Perform Safety Analysis andConsequence Evaluations 3-6

Subprogram 0804: Determination and Verification ofRequired Water Chemistry Limits 3-6

Subprogram 0805: Evaluate Alternate Steam GeneratorMaterials and Processing 3-6

Subprogram 0807: Develop Neutralizer for Crevice Acids 3-6Subprogram 0809: Thermal-Hydraulic Analysis

and Evaluation 3-7Subprogram 0810: Evaluate Methods for Reducing

Carry-Over and Decreasing PressureDrop Through Steam Separators 3-7

Subprogram 0811: Development and Technical Supportof Initial Plant Application ofChemical Cleaning 3-7

Subprogram 0812: Evaluate Secondary SystemLayup Chemistry 3-7

Subprogram 0813: Evaluate Steam GeneratorLayup and Transient 3-8

Subprogram 0814: Evaluate Methods for ReducingTube Vibration, Wear, and Fretting 3-8

Subprogram 0816: Evaluation of On-Line Chelant Additions 3-8Subprogram 0818: Destructive Analysis of

Steam Generator Components 3-8Subprogram 0820: Evaluate Condensate Polishers 3-8Subprogram 0821: Develop High and Low

Temperature Filters 3-9


Table of Contents iii

Subprogram 0822: Evaluate and Test BoilerWater Cleanup Systems 3-9

Subprogram 0823: Instrument Operating Units 3-9Subprogram 0824: Evaluation of Hydrogen

Evolution Monitoring 3-9Subprogram 0830: Improve Control of Condenser

Cooling Water Leakage 3-9Subprogram 0836: Evaluate Secondary System Oxygen

Control Measures 3-9Subprogram 0839: PWR Steam Generator

Technology Transfer 3-10

Steam Generator Owners Group II 3-10Background 3-10Technical Program 3-10

S301: Improved Steam Generator NondestructiveExamination Techniques 3-10

S302: Arrest Steam Generator Intergranular Attack (lGA)and Tube Cracking (SCC) in and Above the TubesheetCrevice and in Other Crevice and Dryout Locations 3-12

S303: Causes and Corrective Actions forPrimary Water Cracking of Steam Generator Tubing 3-12

5304: Destructive Analysis of Steam Generator Components 3-125305: PWR Steam Generator Chemical Cleaning Process

Development and Evaluation 3-12S306: Evaluation and Improvement of Steam Generator

Performance and the Effectiveness of Preventiveand Corrective Measures 3-12

S307: PWR Steam Generator Technology Transfer 3-13S308: Causes and Corrective Actions for Pitting

of Steam Generator Tubing 3-13S309: Minimize the Effects of Sludge, Scale, and

Deposits on Corrosion in Steam Generators 3-13S310: Tube Fretting and Fatigue in

Preheat Steam Generators 3-135311: Tube Support Materials and Designs

and Crevice Corrosion 3-14

Steam Generator Reliability Project 3-14



3-14

3-15

3-193-19

3-143-14

3-193-203-20

3-203-203-213-22

3-233-253-253-263-273-273-273-28

BackgroundTechnical Program

5401: Improved Steam Generator Water Chemistry -Field Studies and Water Chemistry Guidelines

5402: Improved Steam Generator Water ChemistryThrough Improved Balance-of-Plant Operation

S403: Improved Steam Generator ImpurityRemoval Techniques 3-17

S404: Demonstrated Steam Generator In-Service Inspections 3-17S405: Technology Transfer 3-17S406: Steam Generator Primary Side Remedies 3-18S407: PWR Steam Generator Secondary Side Remedies 3-18S408: Improved Materials and Designs for Steam Generator

Repair and Replacement5409: Alternate Secondary Water Chemistry5410: Tube Vibration, Mechanical Damage,

Fretting, and Wear5411: Thermal-Hydraulic Code Evaluation and ValidationS412: Steam Generator Strategic Planning Guidelines

Research FindingsTube Wastage (Thinning)DentingPrimary Side Stress Corrosion CrackingSecondary Side Intergranular Attack andStress Corrosion CrackingPittingCorrosion FatigueTube Fretting and WearSteam Generator Performance

Steam Generator Replacement/Service LifeLost CapacityForced Outages

References 3-31


Table of Contents v

4 Recommendations 4-1

Introduction 4-2

4.1 Steam Generator Design 4-34.1.1 Tube and U-Bend Support Structure Materials 4-34.1.2 Tube Support Structure Designs 4-44.1.3 Tube Materials 4-54.1.4 Tube Fabrication - U-Bends 4-64.1.5 Tube Fabrication - Tubesheet Expansion 4-64.1.6 U-Bend Support Structure 4-74.1.7 Steam Generator Tube Bundle Assembly 4-84.1.8 Mechanical Design - Penetrations 4-84.1.9 Mechanical Design-

Steam-Water Separation Equipment 4-94.1.10 Mechanical Design - Blowdown 4-104.1.11 Mechanical Design - Feed Ring 4-104.1.12 Mechanical Design - Shell 4-114.1.13 Shell Fabrication 4-124.1.14 Thermal Hydraulic Design 4-124.1.15 Design Against Water Hammer and Dynamic Flow

Instability 4-134.1.16 Archive Samples 4-134.1.17 Steam Generator Cleanliness 4-144.1.18 Steam Generator Repair and Replacement 4-15

4.1.18.1 Alternate Tube Repair Limits 4-154.1.18.2 Tube Repair Options 4-164.1.18.3 Tube Peening and In Situ Stress Relief 4-174.1.18.4 Girth Weld Cracking 4-194.1.18.5 Steam Generator Replacement 4-204.1.18.5 Repair/Replacement Options 4-20

4.2 Steam Generator Operations 4-224.2.1 Steam Generator Cleanliness and Cleanliness of

Interfacing Systems During Construction 4-224.2.2 Minimizing Corrosion Product and

Ionic Impurity Transport 4-24


vi Steam Generator Reference Book, Revision 1

4.2.3 Enhancing Hideout Return Processes4.2.4 Crevice Flushing4.2.5 Sludge Lancing4.2.6 Chemical Cleaning4.2.7 Thot Reduction

4.3 Plant Design, Modification, and Operation4.3.1 Steam Generator and Balance-of-Plant Layup4.3.2 Steam Generator Inspection and

Nondestructive Testing4.3.3 Steam Generator Blowdown4.3.4 Condensate Polishing4.3.5 Condensers4.3.6 Water Chemistry4.3.7 Secondary Systems Design4.3.8 Makeup Water Treatment System

4.4 Design and Operation Guidelinesto Minimize Steam Generator Corrosion

4-244-254-264-264-27

4-284-29

4-304-304-314-334-344-354-36

4-39

4-42

4-42

4-40

4-41

4-40

4-434-44

4.4.1 Guidelines for PWR Steam Generator TubingSpecifications and Repair

4.4.2 Plant Design for PWR Steam Generator Inspectionand Nondestructive Testing

4.4.3 Plant Design Guidelines for Layup and Cleanup ofSteam, Feedwater, and Condensate Systems

4.4.4 Guidelines for Design of PWR Steam GeneratorChemical Cleaning Systems

4.4.5 Guidelines for Design of Steam GeneratorBlowdown Systems

4.4.6 Condensate Polisher Design, Operation, andMaintenance Guidelines

4.4.7 Design Guidelines for Plant Secondary Systems4.4.8 Plant Design for PWR

Steam Generator Replaceability 4-444.4.9 Design Guidelines for Layup of PWR Steam Generator 4-454.4.10 Design and Operating Guidelines for Plant Condensers 4-454.4.11 Guidelines for Impurity Removal and Control 4-46

EPRJ Licensed Material

Table of Contents vii

4.4.12 Preoperational Flushing, Cleaning, and Layup of PWRSteam, Feedwater, and Condensate Systems 4-47

4.4.13 Guidelines to Minimize Contamination of PWR SteamGenerators During Plant Construction 4-47

4.4.14 Steam Generator Inspection Guidelines 4-484.4.17 PWR Primary Water Chemistry Guidelines 4-494.4.18 PWR Secondary Water Chemistry Guidelines 4-494.4.19 Guidelines for the Design and Operation of

Makeup Water Treatment Systems 4-49

References 4-50

5 Steam Generator Degradation (Technical Descriptionof Causes, Consequences, and Prevention) 5-1

6 Thermal and Hydrodynamic Analysisof Steam Generators 6-1

7 Primary Water Stress Corrosion Cracking 7-1Introduction 7-2

Babcock & Wilcox 7-3Combustion Engineering 7-4Kraftwerk Union 7-4

Types of PWSCC Degradation 7-4

Extent of PWSCC Degradation 7-7

Description of PWSCC. Degradation 7-13Cracking at Expanded Regions Within Tubesheet 7-13Cracking at Expansion Transitions 7-14

Depth of Expansion Transition Within the Tubesheet 7-15Expansion Method 7-15Longitudinal Cracks at Expansion Transitions 7-17Circumferential Cracks at Expansion Transitions 7-24Cracking at Dented Tube Support Plate Intersections 7-27Cracking at U-Bends 7-27Cracking at U-Bend Apex 7-27Cracking at U-Bend Tangent 7-31

Causes of PWSCC 7-32


viii Steam Generator Reference Book, Revision 1

General Discussion 7-32Material Susceptibility 7-34

Final Mill Annealing Temperature 7-37Carbon 7-39Sensitization and Thermal Treatment 7-43Impurities 7-45

Stress 7-45Expansion Transition Stresses 7-45Dented Tube Support Plate Intersections 7-47U-Bend Stresses 7-47Stress Threshold for LTMA Alloy 600 Material 7-47Influence of Stress on Time to PWSCC 7-48

Environment 7-50Temperature 7-50Hydrogen 7-53Lithium 7-53Electrochemical Potential 7-54

Rate of PWSCC Progression 7-54Expansion Transition PWSCC 7-56Inner Row V-Bend PWSCC 7-56

Detection of PWSCC 7-58Bobbin Coil Eddy Current Testing 7-58Rotating Pancake Coil Eddy Current Testing 7-58Ultrasonic Testing 7-59Leak Testing 7-59Dented Region Inspection 7-60

References 7-61

8 Tube Support and Tubesheet Corrosion(Acidic Crevices-Tube Denting) 81Introduction: Description and Causes of Tube Denting 8-2

PWR Steam Generator History 8-2Steam Generator Design 8-2Steam Generator Materials 8-2


Table of Contents ix

Denting Experience 8-3Failure Analysis of Support Plate Sections 8-3Effects on Tubes, Tube Supports, and Tubesheet 8-6

Causes of Denting 8-9Corrosion Processes 8-9

Nature of the Oxide/Corrosion Product Layer 8-11Crevice Chemistry 8-14Effect of Dissolved Oxygen 8-17Laboratory Denting Experiments 8-18Heat Flux and Concentration Effects 8-18

Isothermal Capsule Tests 8-20Capsule Design 8-20Reference Chemistry 8-20Corrosion Process 8-21Corrosion in Various Chloride Solutions 8-22Effect of Temperature 8-30Alternate Support Plate Materials 8-32Effects of Other Anions 8-34

Heated Crevice Tests 8-36Model Boiler Tests 8-40Effect of Superheat 8-45Summary of Corrosion Rate Test Data 8-47

Prediction of Dent Initiation 8-48

Conclusions 8-52

Improved Operating and Maintenance Practices 8-53

Improved Steam Generator Designs 8-54

References 8-54

9 Tube Wastage and PhosphateSecondary Water Chemistry 9-1Introduction 9-2

PWR Plant Experience 9-3Nature of Phosphate Wastage 9-3


x Steam Generator Reference Book, Revision 1

Field Experience

Laboratory StudiesSodium Phosphate Solution ChemistryPotassium Phosphate Solution ChemistrySodium Phosphate Corrosion TestsInteractions of Phosphate With Magnetite

Discussion

Conclusion

References

10 TUBE PITTINGIntroduction

Scope of ProblemImpact of Tube Pitting on Plant Performance

NDE DetectionLocation of Pit IndicationsDetection and Early Indications of Tube Pitting

PWR Field DataIntroductionMajor Pitting

Indian Point 3Millstone 2Connecticut YankeeTrojanRetired Surry Steam GeneratorCalvert Cliffs

PWR Plant Experience - Minor PittingSummary of PWR Field Data

Laboratory TestsIntroductionSummary of SGOG I WorkOhio State University Test ResultsCombustion Engineering Test Results

9-4

9-129-129-169-179-22

9-23

9-24

9-26

10-110-210-210-2

10-310-310-5

10-910-9

10-1010-1010-1510-2010-2010-2010-2310-2410-24

10-2410-2410-2610-2710-30


Table of Contents xi

Brookhaven National Laboratory 10-40Battelle Columbus Division's Test Results 10-44University of Leuven Test Results 10-50

Causes of Pitting 10-52Sludge and Tube Scale 10-53Oxidizing Conditions 10-54Acid Chloride 10-54Operating Temperature 10-57Theory of Steam Generator Tube Pitting 10-57

Location of Pitting 10-58Pit Initiation 10-59Pit Propagation 10-59Characteristics of Units Most Likely to Develop Pitting 10-63

Utility-Implemented Corrective Actions 10-64

Recommendations to Prevent/MitigateSteam Generator Tube Pitting 10-64

Sludge and Scale 10-68Acid Chloride 10-68Oxidizing Conditions 10-69Temperature 10-69Miscellaneous Recommended Actions 10-69

Layup Chemistry 10-69Eddy Current Inspection 10-70Sleeving 10-70Tube Examination 10-71

References 10-71

11 Tube Supports and Tubesheet Corrosion -Alkaline Denting 111Introduction 11-2

Plant Experience 11-2Denting in PWR Plants 11-2

Fort Calhoun 11-2D.C. Cook Units 1 and 2 11-2


xii Steam Generator Reference Book, Revision 1

Point Beach Units 1 and 2 11-3San Onofre Unit 1 11-3

Summary of Plant Experience 11-3Possible Interaction Between Alkaline Denting and IGA/SCC 11-4

Causes and Mechanism of Alkaline Denting 11-5Laboratory Test Results 11-9

Improved Operating and Maintenance Practices 11-14

Improved Steam Generator Designs 11-15Summary 11-16

References 11-16

12 Secondary Side Intergranular Attack and StressCorrosion Cracking - Plant Experience on AVTWater Chemistry 121Introduction 12-2

Tubesheet Crevices 12-2Tube Support Crevices 12-3Sludge Pile Crevices 12-3Progression of Intergranular Corrosion 12-4Definition of Terms 12-9Summary of Plant Experience 12-12

Locations 12-12Alloys 12-13Contaminants 12-16Temperature and Superheat 12-16Stresses 12-17Cold Work 12-17Electrochemical Potential and Presence of Oxidants 12-17Focus 12-18

Plant Experience: Definition of Problem 12-18Operating History 12-18

Temperature (Hot Leg Versus Cold Leg Location,and Hot Leg Temperature) 12-19

Seawater Site Versus Freshwater Site 12-22


Table of Contents xiii

IGA/SCC at Tubesheet Crevices of Part-DepthRolled Units With LTMA Tubing 12-23IGA/SCC in Hot Legs of Combustion Engineering Units 12-26IGA/SCC at Hot Leg, Drilled Hole TubeSupport Plate Crevices of Units With LTMA Tubing 12-26

Secondary Plant Materials 12-28Impurity Ingress 12-29Water Treatment History 12-32Period of Operation Before First Occurrence -Aging of Material 12-34Presence/Use of Full Flow Condensate Polishers, ProblemsWith Other Ion Exchangers 12-35Use of Boric Acid 12-36Use of Morpholine 12-38Elevation in Tube Bundle 12-38Summary for Units With Mill Annealed Alloy 600 Tubing 12-39

Failure Analysis of Samples 12-41Tubesheet Crevices - Recirculating Steam Generators 12-41

Freshwater Plants 12-42Seawater Plants on AVT 12-47

Top of Tubesheet of Full-Depth Expanded Plants(OD of Expansion Transition at Top of Tubesheet)-Recirculating Steam Generators 12-50

Combustion Engineering Units 12-50Westinghouse-Type Units 12-52

Hot Leg Sludge Piles - Recirculating Steam Generators 12-53Freshwater Plants on AVT 12-53Seawater Plants on AVT 12-53

Hot Leg Tube Supports - Recirculating Steam Generators 12-54Freshwater Plants on AVT 12-54Seawater Units on AVT 12-56

Hot Leg Free Spans in Recirculating Steam Generators 12-57U-Bend Support Region in Recirculating Steam Generators 12-57Cold Legs in Recirculating Steam Generators 12-58

Free Spans 12-58

tJJHI Llcensea malerlal

xiv Steam Generator Reference Book, Revision 1

SupportsTop of TubesheetTubesheet Crevices

Upper Tubesheet Crevice and Upper Tube Supports inOnce-Through Steam GeneratorsLower Tubesheet Crevice and Sludge Pile inOnce-Through Steam GeneratorsSummary of Failure Analysis Results

Effects of Intergranular Corrosion on Tubing Materials

Remedial MeasuresStressMicrostructureEnvironment

Minimization of Tubesheet CrevicesLower TemperatureAdding pH NeutralizersFlushing or SoakingInleakage and Particulate ControlControl of the Concentrating Capability of the Sludge PileRatio ControlAvoidance of Oxidizing ConditionsProtection of Sensitized MaterialInhibitorsRecommendations

References

13 Intergranular Corrosion of Alloy 600 FromCaustic CompoundsIntroductionInvestigation of Caustic Conditions That CauseIntergranular Corrosion

Behavior in Pure Caustic1% Caustic

, 10% Caustic50% Caustic

12-5912-5912-59

12-60

12-6012-60

12-63

12-65,12-6612-6612-6712-6812-6812-6812-6912-6912-6912-7012-7012-7012-7012-70

12-71

13-1

13-2

13-513-613-613-8

13-10


Table of Contents xv

Effects of Other Dissolved Species 13-12Effects of Presence of Solid Oxides 13-16Effects of Concentration 13-18Effects of Temperature 13-19Effects of Stress and Prestrain 13-23Effect of Electrochemical Potential 13-27Effects of Heat Treatment and Material Microstructure 13-30

Model Boiler Tests 13-33

Mechanisms of IGA/IGSCC in Caustic 13-36Oxide Film Rupture 13-37Grain Boundary Properties 13-38

Plasticity at Grain Boundaries 13-39Grain Boundary Energy 13-39Chemical Segregation at Grain Boundaries 13-40Grain Boundary Carbides 13-41

Dealloying 13-42

References 13-44

14 Intergranular Corrosion From Acidic Compounds 141

15 Lead Cracking of Alloy 600 151Introduction 15-2

Plant Experience 15-2Sources of Lead 15-2Typical Lead Levels 15-3Cracking in Steam Generator Tubes 15-5Eddy Current Detection 15-6

Laboratory Experience 15-7

Lead Chemistry 15-13

Discrimination Between Cracking byLead and Other Corrodents 15-15

Possible Remedies for Lead Cracking 15-16

References 15-18


xvi Steam Generator Reference Book, Revision 1

16 Tube Corrosion and Wear: U-Bend Supports (AVBs)and TSP IntersectionsIntroduction

AVBWearPlant ExperienceExamination of Sample TubesModeling of Flow-Induced VibrationsRepairs and Remedial MeasuresConclusions

Cold Leg ThinningPlant ExperienceExamination of Sample TubesMeasurements of Tube MotionsMechanismsLaboratory Corrosion StudiesImpact on Steam Generator Operationsand Potential RemediesNon-Destructive Detection andMeasurement of Cold Leg Thinning

Preheater Wear

Fretting in OTSG Tubes

Summary of Concerns With Corrosion andWear at Support Structures in Nuclear Steam Generators

References

17 Tube Fretting and Wear

18 Tube Fatigue

19 Other Problems

20 Water Chemistry Control

21 Ionic Impurity Control

22 Water Chemistry Options

23 Corrosion Product Control

16-1

16-2

16-616-616-8

16-1116-1216-13

16-1416-1416-1616-1816-1816-21

16-26

16-27

16-27

16-29

16-29

16-30

17-1

18-1

19-1

20-1

21-1

22-1

23-1


Table of Contents xvii

24 Material Selection and Alternative Designs forSteam Generators 24-1Material Alternatives for Tubes and Support Structures 24-2

Tube Materials 24-2Stress Corrosion Cracking 24-4Sulfates 24-33Sulfur 24-35Lead 24-36Intergranular Corrosion 24-39Pitting 24-41Wastage 24-43

Discussion of Tube Alloys 24-47Tube Support and Tubesheet Materials 24-51

Corrosion of Support Materials in Chlorides 24-53Model Steam Generator Test in Sulfates 24-62Electrochemical Tests 24-63Corrosivity of Representative Environments 24-65Effects of Support Hole Design on Corrosion 24-67Matching Service Environments toSupport Alloy Composition 24-69

References 24-70

25 PWSCC Remedies 25-1Introduction 25-2

Regulatory Requirements 25-2PWSCC in Expanded Region 25-5

p* Criterion 25-5F* Criterion 25-5

PWSCC at Expansion Transitions 25-6PWSCC at Dented Tube Support Plate Intersections 25-7PWSCC at V-Bends 25-7

Remedial Measure Strategies by Plant/Material Type 25-8Early Steam Generators With Lower Strength Tubing 25-8Steam Generators With Higher Strength, Non-ThermallyTreated, Alloy 600 Tubing 25-8


xviii Steam Generator Reference Book, Revision 1

Expanded Zone Within the Tubesheet 25-9Part-Depth Roll Expansion 25-9Full-Depth Expansion 25-9Recent Steam Generators With Thermally TreatedAlloy 600 or Alloy 690 Tubing 25-11

Assessing Remedial Measure Effectiveness 25-11Stainless Steel Tubes in Boiling Magnesium Chloride 25-11Polythionic Acid and Sodium Tetrathionate 25-1210% Sodium Hydroxide at 550F (288C) 25-1210% Sodium Hydroxide at 660F (349C) 25-13Elevated Temperature Steam Tests 25-13Primary Water Tests at Elevated Temperature 25-14Primary Water Tests at Operating Conditions 25-14Field Experience 25-14Summary 25-15

Rotopeening 25-15Process Description 25-15Qualification Testing 25-17

Belgian/Westinghouse Development 25-18French Rotopeening Development 25-18

Field Experience 25-19Summary 25-19

Shot Peening 25-19Process Description 25-20Qualification Testing 25-21

Testing of Uncracked Roll Transition Specimens 25-22Testing of Pre-Cracked Roll Transition Specimens 25-22

Field Experience 25-23Summary 25-23

Thermal Stress Relief andHeat Treatment 25-24

Required Time and Temperature for Stress Relief 25-24Tubing Stress Relief 25-24


Table of Contents

Tubing SensitizationTubing Recrystalization and Grain GrowthTubesheet Transformation andFabrication Stress Relief TemperaturesSummary of Stress Relief Time andTemperature Guidelines

Required Time and Temperature forMetallurgical ImprovementIn-Situ Stress Relief and Heat Treatment Methods

U-Bend Stress ReliefLocal Expansion Transition Stress ReliefGlobal Tubesheet Stress ReliefDented Tube Support Plate Intersection Stress Relief

Summary

ElectroplatingProcess DescriptionQualification TestingField ExperienceSummary

Re-Expansion

PluggingWelded PlugsExplosive PlugsMechanical PlugsMemory Metal PlugsSummary

SleevingSleeve DesignsField Experience

Inadequate Heating of Brazed JointsDissolution at Brazed JointsPoor Brazed Joints Due to Axial RestraintLeakage at Hydraulically Expanded JointsPrimary Side ICSCC of Deformed Areas

xix

25-2425-25

25-25

25-27

25-2725-2725-2725-2925-3225-3425-34

25-3425-3525-3625-3625-36

25-36

25-3725-3825-3825-3825-3925-39

25-3925-4125-4225-4825-4825-4925-4925-49


xx Steam Generator Reference Book, Revision 1

Comparative Sleeving Tests at Ringhals 2 25-49Summary 25-50

Temperature Reduction 25-50Laboratory Basis 25-50Field Experience 25-51

Hydrogen Concentration Reduction 25-52Laboratory Basis 25-52Field Experience 25-52

Secondary Side Water Chemistry Control 25-52Denting Control 25-52

Secondary Side Chemical Cleaning 25-53Arrest Denting 25-53

References 25-53

26 Nondestructive Examination 26-1

27 Major Steam Generator Repairs/Replacement 27-1Appendix A A-1

List of Steam Generator Publications

Appendix BSteam Generator Designs

GlossaryGlossary of Terms

Index

B-1

G-1

1-1

1INTRODUCTION

Contributing Author/Editors. J. Green, EPRI1993


1-2 Steam Generator Reference Book, Revision 1

PWR STEAM GENERATORSSteam generators in pressurized water reactor (PWR) nuclear power

plants are heat exchangers (Figure 1-1) . They transfer heat from a primarycoolant system (pressurized water) to a secondary coolant system. Like afossil fuel plant, a nuclear power reactor heats water to produce steam.The steam then drives a turbine which turns an electric generator. ThePWR shown in Figure 1-1 is fueled by slightly enriched uranium in the

FIGURE 1-1Pressurized Water Reactor (PWR) Power Plant

Containment Structure

SteamGenerator

ControlRods

~Waterf~:~::,)~9 Steam

Steam Line

TurbineGenerator

CondenserCoolingWater

form of uranium oxide pellets held in zirconium alloy tubes in the core.Water is pumped through the core and heated by the fission process. It iskept under pressure in the core to prevent boiling. This primary coolantwater completes its cycle by passing through the steam generator,transferring its heat to the secondary coolant water to make steam. ThreeAmerican companies have manufactured PWRs: Westinghouse ElectricCorp.; Combustion Engineering, Inc.; and the Babcock & Wilcox Co. (B&W).The steam generators in these PWRs, as well as those supplied by KraftwerkUnion, Framatome, and Mitsubishi are the subject of this document.(Kraftwerk Union has had a technical interchange agreement withCombustion Engineering, Inc., and Framatome and Mitsubishi with


Introduction 1-3

Westinghouse Electric Corp.) Horizontal steam generators used by theRussians, and CANDV steam generators are not explicitly covered here.However, many of the later chapters contain much pertinent information.

Two types of steam generators are in operation: recirculating and once-through steam generators. B&W supplied a system which employs a once-through steam generator while all the other vendors manufacturedrecirculating steam generators. Babcock & Wilcox Co., Canada, fabricatesvertical recirculating steam generators, also.

Figure 1-2 shows the significant features of a recirculating-type steamgenerator (RSG). A more detailed description of an RSG is given inChapter 2. In a variation of this design, a section of the secondary sideserves as a feedwater preheater to achieve greater thermal efficiency. Inthis case, a section of tubes at the outlet or cold leg side of the V-bends ispartitioned off from the rest of the secondary side to form a preheat section.Water is then fed to the preheat section rather than into the downcomer.Figures 1-3a and 1-3b illustrate the split flow and counter flow inWestinghouse units. Figure 1-3c illustrates the Combustion Engineeringpreheat unit, in particular, the lower part of the bundle.

Figure 1-4 shows a once-through steam generator (OTSG). The primarycoolant flows from top to bottom. The feedwater enters into a feed annulusbetween the 9th and 10th tube support plates, where it is mixed with steamand preheated to saturation. A more detailed description of an OTSG isgiven in Chapter 2.

BACKGROUNDSteam generators in PWRs were designed for a 30-40 year operating

life. However, in the 15-25 years that PWRs have operated commercially,they have experienced reduced reliability. Steam generator tubing and othercomponents have prematurely degraded from such mechanisms asvibration, fretting, high-cycle fatigue, water hammer, stress corrosioncracking, wastage (wall thinning), pitting, intergranular attack, denting,and erosion-corrosion. These problems are widespread. By the end of 1992,approximately 36 of the units in commercial operation had experiencedtube denting, 39 units had showed signs of wastage, 9 had inside-diametertube cracking within the tube sheet crevice, 16 had tube cracking in theV-bend, 40 had experienced outside-diameter stress corrosion cracking andintergranular attack, and at least 20 experienced water hammer, etc. Insome units, some of these problems are arrested or slowed by equipment,design, or operating changes. Without close attention to maintenance andoperation, steam generator operators can expect to experience one or moreof the above problems.



FIGURE 1-2PWR Recirculating Steam Generator

Tube Supports

Tube Bundle

Tube Sheet

Downcomer Annulus

Primary Separators

Secondary Separators

IIc~~--- Feedwater Inlet

t Steam Outlett,~~~~~m~~

'" '"

Primary Inlet Primary Outlet


Introduction 15

FIGURE 13Preheat Units

(a) Split Flow

i i(b) Counter Flow

(c) Axial Flow (cold leg side)


1-& Steam Generator Reference Book, Revision 1

FIGURE 14Once-Through Steam Generator (OTSG)

FeedAnnulus

UpperTubesheet

AuxiliaryFeedwaterInlet

SteamOutlet

FeedwaterInlet

AspiratingSteam

1st Suppor1Plate

LowerTubesheet


Introduction 1-7

Degradation of tubing or support structures often requires unscheduledor extended outages for maintenance. These outages are costly in terms of

, inconvenience, equipment repair, replacement power, and personnelradiation exposure. Continuing problems also increase the probability ofsteam generator replacement before the end of the power plant designlifetime. Two utilities have replaced steam generators in four PWRs afterless than ten years of commercial operation. Steam generators in sevenother units were replaced after only 10 to 13 years of service. A summaryof steam generator replacements through 1993 is presented in Table 1-1.These replacements are expensive and require extensive outages. Estimatesof steam generator replacement costs approach $100 million, which doesnot include replacement power costs.

TABLE 1-1Steam Generator Replacements (1.2)

Year ofCompletion

1980198119821983198319841984198919891989199019911993199319931993

UnitSurry 2Surry 1Turkey Point 3Turkey Point 4ObrigheimPoint Beach 1H. B. RobinsonD.e.eook2Indian Point 3Ringhals 2Dampierre 1PalisadesMillstone 2North Anna 1Beznau 1Doel3

CauseDentingDentingDentingDentingseesecWastagesecPittingsecsecWastageseesecsecsec

Years ofService

789

10141313111214101917152411



By late 1976, many operating steam generators were known to haveexperienced wastage, denting, stress corrosion cracking, apparent fatiguecracking, water hammer, and carryover. It was suspected that tube corrosionwas due, in part, to condenser inleakage. However, there was very littlequantitative data available to define the magnitude of the various damageforms, and without laboratory simulation of the damage, there was littleunderstanding of the causes. For instance, one vendor had postulated thatprior phosphate operation was required for denting to occur (U). Moststeam generators in the United States used phosphate chemistry controloriginally, but have converted to all-volatile treatment (AVT). Almost allwere outfitted with alloy 600 tubes and carbon steel drilled hole tubesupports. The steam generator designs evolved from smaller units; mostwere scaled-up versions of units from the 1950s and 1960s. Thermal-hydraulic analyses of these early designs were limited. Plant designersfocused on increased performance and cost reduction per unit of capacity($/kW). Without quantitative data, utilities had little incentive to maintaintight condensers, isolate air leaks, or shut the plant down in response tohigh levels of contaminants in the steam generators. Nor was there a strongincentive to install condensate polishing and demineralizers, replace feedtrain materials, reroute/add piping to allow removal of contaminants, orto install improved instrumentation for measuring lower levels ofcontaminants and/or corrosion rates. Chemical cleaning and neutralizationwere practices common to the fossil fuel industry, but these concepts werenever demonstrated for nuclear plant application. The only methods fordetecting damage in the steam generator tubes were single-frequency eddycurrent testing and radiation monitors that were used to detect tube leaks.

By 1976, the utility industry recognized that steam generators requiredspecial attention. Corrective actions were needed. The costs to implementthese corrective actions were expected to be very high. In early 1977, theindustry begana major effort to develop methods for improving thissituation. They organized the Steam Generator Owners Group and fundeda 5-year program managed by the Steam Generator Project Office at EPRIat a cost of about $40 million. Twenty-eight utilities supported the OwnersGroup, including utilities from three European countries and Japan. The24 U. S. utilities represented 54 of the 101 PWRs that were planned to be inoperation in the United States by 1986.

The program involved a complex interaction of many systems anddisciplines, such as mechanical, thermal, and hydraulic design of the steamgenerators, water chemistry, control of this chemistry, the design andmaterials for construction of secondary plant components and systems, plantoperation, and steam generator inspection techniques. The objective of thisprogram was to provide improved technology alternatives to the utilities,


Introduction 19

vendors, and architect/engineers so that each utility could select the mostappropriate options, as well as develop a specific plan for improving steamgenerator performance.

This five-year program was completed successfully. However, newchallenges emerged while this program was under way, and a new groupcalled Steam Generator Owners Group II was formed in 1983 to addressthese new problems over the period 1983-1986. The approach and objectivesof the new program were similar to those of the first Owners Group. Itsbudget was about $29 million. Thirty-seven utilities, including utilities fromsix European countries and Japan supported this activity.

This program was also successfully completed. Again, new steamgenerator challenges continued to arise. Therefore, a new EPRI-fundedeffort, the Steam Generator Reliability Project (SGRP), was formed to operateat a funding level of $30 million over the period 1987-1992. Five Europeancountries, one Canadian utility, and one Japanese utility are participatingin this program under technical exchange agreements.

REFERENCES1.1 "Steam Generator Update-1976./I Steam Generator Symposium,

Westinghouse Electric Corp., Pittsburgh, PA, July 1976.1.2 "Steam Generator Progress Report, Revision 10./1 EPRI Steam

Generator Management Project. November 1994.

2STEAM GENERATORPERFORMANCE HISTORY

Contributing Authors/EditorsS. J. Green, EPRIJ. A. Mundis, Southern California Edison Co.T. Oldberg, EPRIC. S. Welty, EPRIJ. P. N. Paine, EPRI



INTRODUCTIONThis section provides a description of the pressurized water reactor

(PWR) for those unfamiliar with this type of power plant. It also discussesthe design features that impact steam generator operating performance andreliability.

The technology that evolved into the modern PWR steam generatorand its related systems was greatly influenced by the fossil-fired drumboilers which were first widely used to generate electricity commercially50 years ago, and by the power plants used in the U.s. navy nuclear powerprogram.

PRESSURIZED WATER REACTOR (PWR) POWERPLANT DESCRIPTION

In general, PWR power plants generate heat by the fission of slightlyenriched uranium in a reactor core (Chapter I, Figure 1-1). Pressurizedwater is used to transfer this heat to steam generators, where the heat isused to produce steam to drive the turbine generator. The steam generatorsare shell and tube heat exchangers, with the reactor coolant (the primaryside) inside the tubes and the feedwater / steam on the shell side (thesecondary side). The PWR steam generators must be designed to avoidleakage of the radioactive water, which is used for core cooling, into thenon-radioactive water in the steam system.

The PWR power plant has four water systems that influence steamgenerator performance: primary system, secondary system or steam cycle,condenser cooling water system, and makeup water system.

The primary system is a closed cycle cooling circuit that removes heatgenerated by the fission process in the reactor core and transfers it to thesecondary system. The principal components are the reactor vessel andcore, the primary side of the steam generator, the pressurizer, and the reactorcoolant pumps. The primary coolant is pure water, with additions of lithiumand boric acid, which is maintained at a pressure of about 2,250 psia tominimize boiling in the core. It is pumped by the reactor coolant pumpsthrough the reactor core, through the steam generator tubes, and back tothe reactor coolant pumps.

The secondary system is another closed cycle cooling circuit where heatis removed from the primary coolant to generate steam on the shell side ofthe steam generators at design pressures of 770-1,050 psi. The steam flowsthrough the high pressure turbine, the moisture separator/ reheater (MSR),the low pressure turbine, and then to the condenser. The condensate is


Steam Generator Performance History 2-3

then pumped forward through a series of components such as thecondensate polishing system (if so equipped), the low pressure feedwaterheaters, the deaerating feedwater heater and storage tank (if so equipped),the high pressure feedwater heaters, and then to the steam generator torepeat the cycle. The low pressure heater drains are normally routed to thecondenser where they return to the cycle with the initial condensed steamfrom the low pressure turbine. The high pressure heater drains and MSRdrains, which consist of about 30% of the total flow to the steam generators,are generally pumped forward to rejoin the cycle prior to the last, high-pressure stages of feedwater heating.

The condenser cooling water system is an open or semi-open coolingcycle which functions as the heat sink for the steam cycle. As will bediscussed in more detail below, the water in this system can introduce asignificant quantity of harmful impurities to the secondary system throughcondenser leakage.

The makeup water system is used to purify site water to provide highpurity water to the primary and secondary systems to compensate for lossesfrom these systems. Depending on its design and operation, the makeupwater system can also be a significant source of impurities to both the

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