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Steam Generator Chemica l C leaning Exper iences (1998- 2002)

S. EvansFramatome-ANP, I nc .

Lynchburg, VA

JF RemarkFramatome ANP, I nc .

Lynchburg, VA

S. WatsonFramatome-ANP, I nc .

Lynchburg, VA

F. Am man nFramatome ANP, GmbH

Er langen , GERMANY

A B S T R A C T

Since 1998, a number o f s team generator chemica l c lean ings have been per formed in Nor thAm er ica and wo r ldwide w i th the ob jecti ve reduc ing the corros ive impa ct o f s team generatorsecondary s ide depos i ts on the s team generator tubes and to improve the heat t ransferper forman ce of the s team generator . Dur ing the las t four years , c lean ings have bee nper formed on a numb er o f d i f ferent types of s team generators . The se c lean ings used avar ie ty o f c lean ing proce sses inc lud ing h igh tem perature p lant heat processes, e xterna l heat

crev ice c lean ing proce sses and bu lk depos i t removal processes. Each is un ique in nature dueto cleaning object ives, dep osi ts character ist ics, system de sign and appl icat ion st rategy. Thispaper descr ibes the exper iences and resu l ts f rom four o f the most recent s team generatorchemical c leaning projects in the US since 1998.

Key Terms: chem ica l c lean ing, corros ion m oni tor ing, h igh temp erature chem ica l c lean ing,EPRI /SGOG, low temperature chemica l c lean ing, crev ice c lean ing

CORROSION2003 Paper No.

03579

1

Copyright

2003 by NACE International. Requests for permission to publish this manuscript in any form, in part or in whole must be in writing to NACE

International, Publications Division, 1440 South Creek Drive, Houston, Texas 77084-4906. The material presented and the views expressed in this paper are

solely those of the author(s) and not necessarily endorsed by the Association. Printed in U.S.A.

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I N TRODUCT ION

As the nuclear industry moves into the new mi l lennium, ut i l i t ies cont inue to beconcerned wi th mi t igat ing cor ros ion issues resul t ing f rom bui ldup of secondary s ide deposi ts .Many ut i l i t ies have appl ied for l i fe extensions and are weighing the pros and cons of steamgenerator chemical c leaning, and the associated impact on outage t ime and cost , versus thepotent ia l benef its . Each station that per forms a steam gen erator chemical c leaning hasdi f ferent object ives and goals. The se vary ing object ives and g oals in f luence the type of

cleaning appl icat ion that is performe d. I t has bec om e essent ial that che m ical cleaningappl icat ions accompl ish the stat ion 's goals and object ives of removing the unwanted deposi tmater ia l whi le min imiz ing co st and cr it ica l path schedule impact . Fram atom e AN P (FAN P) hasper formed four chem ical c leanings us ing four d if ferent chem ical c leaning app l icat ion scen ar iosin the Uni ted Stated in the last four years. The se c leanings were c ondu cted a t Salem NuclearGenerating Station Unit 2 (S_alem -2) in Apr i l 199 9 ~, Da vis-Bes se Nu clear P ow er Stat ion Uni t 1(Davis-Besse) in Apr i l 20002 , W ater ford Steam Elect ric Station U ni t 3 (W -3) in Octob er 20003,and Pa lo Verde Nuc lear Genera t ing S ta ti on Un it 1 (P V N G S- 1) in Septem ber 20024. Inaddi t ion to these c leanings, ten h ig h tempe rature c leanings a lso were p er forme d in Canadaand Europe s ince 1998. This paper summar izes the stat ions ' goals and object ives, thedi f ferent chemical cleaning appl icat ions used and the resul ts at each stat ion.

The chemical c leaning of the secondary s ides of each of the four s team generators(SGs) of the Publ ic Serv ice Elect r ic and Gas' (PSE&G) Salem-2 stat ion was per formed dur ingRefuel ing Outage 10 (RFO-10) in the spr ing of 1999. The object ive of the c leaning was toremove the maximum amount of deposi ts and a l lev iate the dent ing phenomenon before i treached the stage of causing outer d iam eter s tress corros ion cracking (OD SC C). A secon daryobject ive for PSE&G at Salem-2 was to restore fu l l s team pressure before power output wasreduced for the p lant due to poor he at transfer.

Davis-Besse is owned and operated by Fi rs t Energy Nuclear Operat ing Company(FENO C). Dav is-Besse's pr ime object ive for c leaning both of thei r once- through steam

generators (OTSGs) was to remove as much secondary s ide deposi t as possib le to a l lev iatethe increasing steam generator pressure drop and improve downcomer water level before i t

reduced pow er output of the p lant.

W ater ford Uni t 3 owners, Entergy Operat ions, In c. (EOI) , decided to chem ical ly c leanthe W-3 SGs to mi t igate or prevent potent ia l tube cor ros ion phenomena due to f lowaccelerat ion in regions of the steam generator . This pheno me non had been observed insimi lar ly designed plants, such as San Onofre, Palo Verde, Calvert Cl i f fs, and ANO-2, as aresult o f bui ldup of bulk depos i ts on the second ary s ide of the SGs. An e qual ly impo r tantobject ive was the removal of lead contaminat ion f rom the steam generator , which couldpromote lead- induced intergranular at tack/stress corros ion cracking ( IGA /SCC ) . A f ina l

object ive establ ished by EOI was to per form the chemical c leaning wi th in of a 30-day outagewindow.

After successful chemical cleanings at al l three uni ts in 1994 and 1995, Ar izona Publ icServ ice (APS) ope rate d the Palo V erde Nuclea r Gen erat ing S tat ion wi thout d if ficu lty un ti l a

decl ine in Probabi l i t y of Detect ion (POD) dur ing Eddy Cur rent Test ing (ECT) was exper iencedin t h e r ecen t o u ta g es a t Un it s 2 an d 3 . Base d o n th e cu r ren t SG re p lace m en t sc h ed u le fo r t h e

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var ious Palo Verde un i ts , APS dec ided to che mica l ly c lean Uni ts 1 and 3 aga in pr ior torep lacem ent to remove bu lk depos i ts to e l iminate the potent ia l fo r mid-cyc le outages.

Q U A L I F I C A T I O N

Qual i f ica t ion programs were conducted for each o f the chemica l c lean ing scenar ios .These programs var ied f rom condi t ion eva luat ions to ex tens ive laboratory tes t ing andqual i fica tion. The eva luat ions inc luded mater ia l surveys and rev iews for corros ion

suscept ib il it y , corros ion a l lowan ce e st imat ions, de pos i t load ing est imates, c orros ion m oni toringp lans and def in i t ion o f techn ica l requ i rements for the chemica l c lean ing app l ica t ion.Laboratory tes t ing cons is ted o f d isso lu t ion and corros ion tes t ing that incorporated actua l ands imula ted s team gene rator depos i ts and cr it ica l m ater ia ls o f const ruc tion.

Surveys o f the var ious mater ia ls o f const ruc t ion used to fabr ica te the s team generatorand i t s secondary systems were per formed to ident i f y a l l mater ia ls /components that would bewet ted by the chemica l c lean ing so lvents. These ma ter ia ls /com pone nts were used to def inethe corros ion a l lowance based on the amount o f operat iona l and chemica l c lean ing corros ionto be exper ienced by the wet ted sur faces. Th is eva luat ion is s imi lar to prev ious eva luat ionsper formed for o ther chem ica l c lean ings. Sum ma r ies o f the corros ion a l lowances o f the

specif ic mater ia ls evaluated in each of the three ut i l i t ies are provided in Table 2, Table 4,Tab le 6 and Table 8 .

Mater ia ls eva luat ions a lso were conducted to ident i f y any mater ia ls prev ious ly untestedin the chemica l c lean ing env i ronment and those mater ia ls that were most suscept ib le tocorros ion in the chem ica l c lean ing env i ronment . Thos e mater ia ls ident if ied as mo stsuscept ib le ( i .e. , most l ikely to experience the highest corrosion as a result of exposure to thechemica l c lean ing so lvents) and most c r i t ica l ( i .e . , those mater ia ls /components w i th thesmal les t corros ion a l lowance) were des ignated in moni tor ing dur ing e i ther or both tes t ing andthe actua l chemica l c lean ing app l ica t ion. The m ost suscept ib le weld m ater ia l was the sh ie ldedme tal arc weld using E 7018 f i l ler metal for a l l of the ut il i ties. How ever, the mo st

suscept ib le /most c r i t ica l base meta ls var ied a t each s i te f rom SA-533 Gr. A , A ISI -1015, A lS l -1018 and AIS1-1008. The mo st cri t ical base m etal wa s dif ferent for each of the ut i l it ies basedon the corros ion a l lowance s set for the chemica l c lean ing. Howe ver , in each set o f SGs, eventhough d i f fe rent makes and models (West inghouse Model 51, B&W OTSG, and CE Models3410 and System 80) were used at each ut i l i ty , the most cr i t ical mater ia l was the materia l usedto fabr ica te the tube s uppor t s t ruc tures. The mater ia ls w i th the lowest corros ion were SA -285Gr. C carbon s tee l in the Salem-2 generators , SA-515 Gr. 70 carbon s tee l in the Dav is-Bessegenerators , SA-570 carbon s tee l in the W-3 generators , A-240 Type 405/A-176 Type 409

sta in less s tee ls in the PVN GS-1 generators .

The f irs t chem ica l c lean ing was conducted a t Sa lem-2. The Sa lem-2 chem ica l c lean ing

p r o c e s s w a s b a s e d o n te c h n o lo g y d e v e lo p e d b y t h e S t e a m G e n e r a t o r O w n e r s G r o u p ( S G O G )und er the spon sorsh ip of the Elec tr ic Pow er Res ear ch Ins ti tu te (EPRI) . Since m agnet i te , with

som e coppe r , was the ma jo r com pone n t o f the Sa lem-2 s e con da ry s ide SG depos i t s , a th ree -

step process for depos i t removal was proposed and qua l i f ied . The process cons is ted o f ani ron (bulk) removal s tep , a c revice-c leaning s tep , an d a comb inat ion co pp er removal and

pass iva t ion s tep . Qual if ica t ion tes t ing cons is te d of a two -ph ase tes t seq ue nc e to eva lua te the

ef fec t iveness o f the process in removing bu lk depos i ts , tube sca le and crev ice depos i ts ; toconfi rm the corros ion re spo nse of se lec t m ater ia ls ; and, to qual ify the u ngro und ed corros ion

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mo nitor ing system (U CM S) for use at Salem-2. This part icular corrosion m onitor ing systempreviously was ut i l ized dur ing the San Onofre Nuclear Generat ing Stat ion Unit 3 (SONGS-3)chem ical c leaning and succe ssful ly mon itored corrosion throug hou t the appl icat ion. Based onqual i f icat ion test ing, the proposed cleaning process removed approximately 97% of theavai lable deposi ts wi th opt imum removal of 90-95% of the crevice deposi ts and acceptably lowcorrosion.

The Davis-Besse chemical c leaning qual i f icat ion did not require a s imulated test

program. A qual i ficat ion study of the AN O-1/Oc onee-1 and TM I-1 qual i f icat ion program s andchemica l c lean ing appl icat ions conducted on once- through s team generators (OTSGs) wasperformed. The propose d process was deeme d qual if ied for the Davis-Besse appl icat ionbased on the simi lar i ty between the Davis-Besse deposi ts and previously qual i f ied andcleaned OTS Gs. Dep osi t loading and ma ter ials evaluat ions speci f ic to the Davis-Be sse steamgenerators were performed as part of the qual i f icat ion as wel l as ref inement of the solventchemis t ry for the Dav is-Besse s team generators . The D av is-Besse chemica l c lean ingappl icat ion con sisted of a bulk i ron dissolut ion step and an E PR I/SGO G passivat ion step sincethe Davis-Besse deposi ts contained essent ia l ly no cop per deposi ts. As in the Salem -2chem ical c leaning ap pl icat ion, th e corrosion respon se of select mater ials was mon itoredthroughout the c lean ing us ing the UCM S a l lowing opt imum contro l o f the process.

Contrary to the Salem-2 and the Dav is-Besse chemica l c lean ings that implementedmod ified EP RI/SG OG processes, the W aterford-3 c leaning ut il ized a techn olog y developed b yFramatome ANP, Gm bH ( former ly S iemens KWU ). A l though applied and quali fied man yt imes in Europe, in a jo int ef fort, the c leaning adap tat ion study for W-3 qual i f ied a non- inhibi tedhigh temperature i ron removal step fol lowed by a high temperature copper removal step usinga techn ology not previously imp lemen ted in the United States. Qu al i ficat ion testing consistedof three phases. The f inal process appl icat ion was based on the est imated de posi t loading ineach of the W-3 steam generators and was designed for opt imizat ion dur ing the f ie ldappl icat ion. Each proce ss step used plant heat for tem perature c ontrol wi th vent ing to achievemixing. Due to the nature of the process appl icat ion, corrosion m onitor ing probes and probe

posi t ioners were not installed pr ior to the cleaning appl icat ion. The process wa s mon itored bychem istry response dur ing appl icat ion. Final corrosion est imates for the cleaning we re basedon pre- and post- chemical c leaning eggcrate dimensions measured dur ing visual inspect ion ofthe SGs at the prev ious outage and immediate ly fo l lowing the complet ion o f the chemica lc leaning.

The PVNGS-1 chemical c leaning qual i f icat ion ut i l ized the test ing and evaluat ionsperformed in 1995 for the or ig inal propr ietary inhibi ted High Temperature Chemical Cleaning(HTC C) appl icat ion. 5 A dep osi t loading est ima te for the PVN GS-1 wa s calculated based oncorrosion product t ransport data s ince the chemical c leaning in 1995 as part of the evaluat ionsperformed in preparat ion for the second cleaning appl icat ion. Based on the object ives of the

cleaning and the est imated deposi t loading, the cleaning appl icat ion used in 1995 wasmodif ied s l ight ly to el iminate the crevice c leaning appl icat ion and the corrosion monitor ing sidest ream mon i tor (SSM) requi rements . The P VN GS -1 chemica l c lean ing appl icat ion cons is tedof a h igh temperature bu lk i ron d isso lu t ion s tep and an EPR I/SG OG pass ivation s tep s ince thePVNG S-1 depos i ts conta ined essent ia lly no copper depos i ts . The corros ion response for themater ials was considered bound by the 1995 appl icat ion such that no corrosion monitor ing

was implemented.

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In pa ra ll e l w i th the deve lopm en t o f the EPR I /SGO G process , a non - inh ib i t ed h ightempe ra tu re chemica l c lean ing p rocess was deve loped in Germa ny and used ex tens ive l y toc lean more than 100 s team genera to rs wor ldw ide . Qua l i f i ca t i on was pe r fo rmed in l abo ra to rytests pr io r to each o f these app l ica t ions inc lud ing mater ia ls rev iew, depos i t load ing andd is t r ibu t ion, and s i te spec i f ic so lvent opt imizat ion. In the course o f these qua l i f i ca t ioneva lua t ions , an ex tens ive m a te r ia l s da tabase w as co l l ec ted tha t cove rs mos t o f t he SGma ter ia ls in Euro pe and Jap an. S ince th is process is usu a l ly app l ied dur ing a shut dow n of ap lant , inser t ion o f cor ros ion coupons or an on- l ine cor ros ion moni tor ing system is not poss ib le ,

thus, a process moni tor ing system us ing the H2/N2 ra ti o was deve lope d and app l i ed i n the W-3chemica l c lean ing app l i ca ti on . The m os t recen t app l i ca ti on o f t h is t echno logy was a tNecka rwes the im Nuc lea r Genera t ion S ta ti on Germa ny (GKN 1 ), wh ich i s de ta i led he re in .

C H E M I C A L C L E A N I N G S Y S T E M

The ch emica l c lean ing sys tem s used fo r each o f t he app l i ca t ions w ere des igned fo rmob i le ope ra t i on and were s it e spec if ic . Mo du la r equ ipm en t , cons is t ing o f va r ioussubs ystem s, a l lowed for se tu p f lex ib i li t y a t the d i f fe rent locat ions for the d i f fe rent processtechn iques app l ied . A l l equ ipm en t and com pone n ts were pos it ioned w i th in be rmed a reas ,

des igna ted as rad io log ica l l y con t ro l l ed a reas (RCAs) , ou ts ide the con ta inmen t bu i l d ings .These a reas were es tab l i shed to con ta in any poss ib le sp i l l o f chemica l so lu t i ons tha t mayhave been used in the chemica l c lean ing system and potent ia l ly conta ined rad io log ica lcon tamina t ion . The p r imary com pone n ts o f t he d i f fe ren t sys tems inc luded p rocess pumps ,chemica l and /o r was te s to rage tanks , va r ious hea te rs and t rans fe r pumps , and p ip ing runs .Othe r componen ts no t cons ide red a po ten t ia l r ad io log ica l haza rd and loca ted ou ts ide thebermed areas inc luded the chemica l tankers , bu lk chemica l conta iners , cont ro l t ra i le r , c rewt ra i le r , chemist ry laboratory (as app l icab le) , t ransformer t ra i le r and spare par ts t ra i le r .S ign i f ican t l y l ess equ ipm en t was requ i red fo r t he W-3 , PVNG S-1 and Eu ropean(Neckarwe the im) chemica l c lean ings based on the app l i ca t i on techn ique us ing p lan t supp l i ed

heat w i th no externa l rec i rcu la t ion .

C L E A N I N G A P P L I C A T IO N S A N D R E S U L T S

S a l e m N u c l e a r G e n e r a t i n g S t a t io n U n i t 2 (S a l e m - 2 )

Clean ing A ppl ica t ion. The S a lem -2 chem ica l c lean ing wa s in i tia ted on Apr i l 14 h andcom pleted on Apri l 28 th, 1999. Th e ch emical c leaning con s is ted of an init ia l chec kou t r inse

and hea tup fo l lowed by bo th an i ron and subsequ en t c rev ice c lean ing app l i ca ti on . Once thebulk of the i ron dep os i ts had bee n remo ved, a ser ie s of low volum e r inses (LVRs) and a full

vo lume r inse (FVR) were app l ied . The f ina l p rocess app l i ca ti on cons is ted o f the pa ten tedcopper pass ivat ion s tep des igned to dissolve any avai lable copper while providing a f lash-

rus ti ng p ro tec t ive pass ive l aye r. The S Gs were r i nsed w i th LVR s and a coo ldown FVR wasimplem ented prior to comp let ion of the chemical c leaning. The che mical c leaning pro ces s

wa s app l ied in ser ies in each s et o f two s team g ene rators (SG s) . A l l so lven ts were app l ied toa level approxim ately 6" (~15 cm) abo ve th e top of the tub e b undle e xc ept the crevice-c leaning

s tep. The c rev ice so lven t was app l i ed a t va ry ing leve ls in t he SG s up to a max im um he igh t o fapproxim ately 30" (~76 cm) abo ve th e 6 th tube supp ort p la te (TSP). During the crevice-

c lean ing s tep, so lvent bo i l ing was implemented v ia vent ing a t s ix leve ls in the SGs to rep len ishsolvent in the crevice region and improve overall crevice dissolution. Th e bulk of the de pos i ts

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were removed w i th an EP RI /SGO G i ron d isso lu tion s tep app l ied a t ~200°F (93°C) for 15 hoursin each set o f SGs pr ior to the crev ice c lean ing app l ica t ion. The nom ina l app l ica t ion t ime ofthe crev ice-c lean ing s tep was approx imate ly 45 hours and app l ica t ion temperature rangedf rom 230-250°F (110-121°C). The copp er pass ivation process was app l ied fo llow ing thecrev ice-c lean ing s tep for an add i tiona l 10 hours . So lvent mix ing and tem perature cont ro l wasachieve d by recirculat ion of the solvents in the SGs during each of the appl icat ion steps. Inadd i t ion to the three major process s teps, r inse so lu t ions were employed a t var ious t imesthroughout the app l ica t ions.

Corros ion Moni tor ing. Corros ion moni tor ing was conducted w i th the UCMS . Both f reeand galvanic corrosion was monitored using in-s i tu corrosion monitor ing probes instal led in thehand ho les located app rox ima te ly 24" (61 cm ) above the tubesheet . In add it ion to on- l inecorros ion moni tor ing, 20 coupons o f 7 d i f fe rent mater ia ls were mounted on the corros ionprobe to me asure to ta l corros ion a f ter the c lean ing was comp lete . The ind icated corros ionrates moni tored by the UCMS were used to es t imate the amount o f corros ion occurr ing in theSG s at the 7 " TS P tha t was ident i fied as a cr i tical com po ne nt w ith a l imit ing co rrosional lowan ce. Al l TS P crevice s also had a l imited diam etral corrosion al low ance , or a l imitedam ount o f c learance a l lowable around each tube a t each TSP. Min imal corros ion wasexpected at the 7 " TSP due to f in i te solvent contact .

Resu l ts . A to ta l o f 14,497 Ibs (6 ,576 kg) o f depos i t were rem oved f rom the seconda rys ide o f Sa lem -2 SG s v ia chemica l c lean ing and p ost -c lean ing s ludge lanc ing. The bu lk o f thedepos i ts was magnet i te , Fe30, (~96%). Copper and n icke l depos i ts in the SGs were min imal(<2%) w i th a t race am ount o f z inc . A depos i t summ ary can be found in Tab le 1 . Of the to ta lam ount removed, approx im ate ly 1 ,233 Ibs (559 kg) was removed v ia s ludge lanc ing. Th iswas a combinat ion o f ex fo l ia ted mater ia l that set t led onto the tubesheet o f each o f the SGsbefore i t cou ld be d isso lved, and pre-ex is t ing tubesheet s ludge that was not d isso lved dur ingchemica l c lean ing. Prev ious s ludge lanc ing operat ions had on ly remov ed between 25 Ibs

(11.3 kg) and 30 Ibs (13.6 kg) of s ludge f rom each SG.

Corros ion observed dur ing the chemica l c lean ing based on the ind icat ions o f the UCMSand corros ion spec imens were wel l be low the l imi ts set for the var ious cr i t ica l componentspresent in the SGs as show n in Tab le 2 . For SA-285 Gr. C, used to fabr ica te the TSPs, the

ma ximum to ta l corros ion, ga lvan ic and free, was 1 .98 mi ls (50.3 ~M). The ca lcu la tedcorros ion va lues for the d iamet ra l c learance between the tube suppor t p la te and the SG tubewere based on the ga lvan ic por t ion o f the data m oni tored d ur ing the c lean ing app l ica t ion. Acorrelat ion factor of 0.4, based on qual i f icat ion test ing, was used to determine the crevicecorros ion f rom the ga lvan ic corros ion. The corros ion o f the u pper TSP s (4 , 5 , and 6) is lowerdue to a shor ter exposure t ime to the chemica l c lean ing so lvents s ince the crev ice c lean ing

step was appl ied at varying levels.

Deta i led v isua l examinat ions o f the SGs were per formed both before and a f ter thechemica l c lean ing app l ica t ion. Typ ica l photographs are ava i lab le in F igures 1 through 4.A l though the tubes and suppor t p la tes were essent ia l ly 100% f ree o f depos i ts , some tubeco l la rs were v is ib le in the tube sheet area. It was s om ew hat m ore d i f ficu l t to assess thec lean l iness o f the crev ice reg ions f rom v isua l inspect ion; however , eddy current tes t ingexhibited very c lean and clear s ignals indicat ing that very l i t t le deposit remained with in the

tube/ tube suppor t p la te crev ices.

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D a v i s - B e s s e N u c l e a r P o w e r S t a ti o n U n i t I ( D a v i s - B e s s e )

Clean ing Ap p l ica tion . The Dav is -Besse chemica l c lean ing was in it ia ted on Apr i l 11 thand com pleted on Apr i l 22 nd, 2000. The c hem ical c leaning cons is ted o f an in i tia l chec kou tr inse and he atup fo l lowed by an i ron remova l s tep. On ce the bulk of the i ron depo sits hadbeen removed, a ser ies o f low vo lume r inses (LVRs) and a fu l l vo lume r inse (FVR)/pass iva t ionwere app l ied to p rov ide a p ro tec t ive pass ive layer p r io r to open ing the SGs fo l lowing thechemica l c lean ing app l ica t ion fo r the rem ainder o f the ou tage m a in tenanc e work . The

chemica l c lean ing p rocess was app l ied in ser ies in the each o f the two O TS Gs. A l l fu ll vo lumeso lven ts were a pp l ied to a leve l approx ima te ly 6 " (~15 cm ) above the 9 h TS P or 363" abovethe top of the lowe r tubes heet. Th e iron d issolut ion step was ap pl ied at ~20 0°F (93°C) for 14hours in each o f the OT SG s. So lven t m ix ing above the 7 h TS P w as ach ieved by d ra in ing thesolvent f rom the S Gs and ref i l l ing four t imes du r ing the proce ss appl icat ion. This dra in and f il lsequence ensured so lven t homogene i ty and min imized reg ions o f po ten t ia l ly dep le ted so lven tabove the 7 h TS P tha t m igh t o therwise have occur red s ince the rec i rcu la t ion f low pa th wasth rough the handh o le jus t be low the 7 h TS P and lowe r ma nw ay jus t be low the 1st TSP.

Tempera tu re , however , was eas i ly ma in ta ined v ia rec i rcu la t ion o f the so lven t th rough heatexchangers . The f ina l rinse /pass iva t ion wa s comple ted in 8 hours , once r inse chem is t ry wasdetermined to m eet spec i fica t ion and no re fo rmu la t ion o f the so lu t ion was requ i red . Coo ldow n

requ i red approx imate ly 15 hours to ach ieve 90°F (32°C) in the SG bund le w i th an averagecooldown rate of approximate ly 7.3°F/hr (2.1°C/hr) .

Corros ion Mon i to ring . Corros ion mon i to ring was conduc ted wi th the UC MS . Both f ree

and galvanic corros ion wa s mon itored us ing in-s itu corros ion mo nitor ing pro bes insta l led in thetwo hand ho les per SG, 24" above the lower tubesheet . In add i t ion to on- l ine cor ros ionmon i to r ing , 16 coupons o f 3 d i f fe ren t mater ia ls o f co r ros ion coupons a lso were mounted onthe cor ros ion p robes to measure to ta l co r ros ion a f te r the c lean ing was com ple te . The land

reg ions o f the TSPs had been iden t i f ied as the most c r i t ica l component and were ass igned a

corros ion l imit o f 9 mi ls per surface or 18 mi ls d iametra l increase.

Resu l ts . A to ta l o f 6 ,036 Ibs (2 ,738 kg) o f depos i t were remov ed f rom the sec ondarys id e o f Da v i s -B e sse S G s v ia c h e m ic a l c le a n in g a n d p o s t -c l e a n in g s lu d g e l a n c in g . T h e b u lk o f

th e d e p o s i t s wa s c o mp o se d o f ma g n e t i t e , F e 3 0 4 ( - -9 7 %) wh i le n ic k e l o x id e wa s o n ly a f r a c t io n

of the depos i ts p resent in the SG s (<2% ) wi th a t race amo unt o f z inc . A sum m ary o f thed e p o s i t s i s p re se n te d in T a b le 3 . Of th e to tal a m o u n t r e mo v e d , a p p ro x im a te ly 9 2 8 Ib s (42 1

kg) was removed v ia s ludge lanc ing .

Corros ion observed dur ing the chemica l c lean ing based on the ind ica t ions o f the UCMSa n d c o r ro s io n sp e c i m e n s we re we ll b e lo w th e l im it s se t fo r th e c r it ic a l T S P l a n d c o m p o n e n t in

Tab le 4 . For SA-285 G r . C, used to fabr ica te the TSPs, the m ax imu m to ta l co r ros ion , ga lvan ica n d f re e , wa s 0 .5 6 9 mi l s . S l ig h t ly h ig h e r c o r ro s io n wa s o b se rv e d in S G 1 BW d u e to a h ig h e r

depos i t load ing than in SG 2AE . Deta i led v isua l exam ina t ions o f the SGs bo th be fo re anda f t e r th e c h e m ic a l c l e a n in g a p p l i ca t io n in d ic a te d v as t ly in c re a se d c le a n l in e ss p o s t -c h e m ic a l

c lean ing . The tubes and suppor t p la tes were essent ia l ly 100% f ree o f depos i ts . Eddy cur ren t

te s t ing exh ib i ted ve ry c lean a nd c lea r s ign a ls r epr ese n ta t ive o f ve ry li tt le dep osi t , i f any , on the

tube sur faces o r w i th in the tube / tube suppor t p la te c rev ices . Some typ ica l pho tographs a re

shown in F igure 5 th rough F igure 10 .

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W a t e r f o r d S t e a m E l e c t ri c S t a ti o n U n i t 3 ( W - 3 )

Cleaning Appl ica t ion. The W -3 chem ica l c lean ing was in i tia ted on O ctober 14 h andcom pleted on O ctob er 19 n, 2000. I t consisted o f a non-inhibi ted h igh tem pera ture ironremoval s tep and a h igh tem perature co pper removal s tep us ing p lant prov ided heat. Thechemical c leaning process was appl ied in series for the iron removal step and in paral le l forthe copper removal s tep in the two SGs w i th one or the o ther SG act ing as a heat s ink , asneede d. Al l solven ts we re appl ied to a f inal level at the top of the tube bundle. The iron

removal s tep was app l ied in increments f i l l ing f rom the bot tom af ter the SGs had reachedMo de 4, a ppro xim ately 320 °F (160°C), an d w ere drained to an in i tia l level at abou t the 4 ~TSP. So lvent mix ing was ach ieved v ia min imal venting dur ing concen t ra ted chem ica l in jec tionby opening the A DV s s l ightly as wel l as w i th so lvent bo i l ing v ia hard ven ts a t each so lvent leve lin the SGs during the iron step. The nom inal appl icat ion t ime of the iron rem oval step wa sapprox im ate ly 12-16 hours . A f ter vacuum dry ing the SGs, the h igh tempe rature copperremoval s tep was app l ied for an add i tiona l 35-40 hours . So lvent mix ing was ach ieved bysparging with air and pressurizat ion/depressurization cycles implem ented thro ugh out theappl ica tion s tep. Fo l low ing the copper removal s tep, a ser ies o f LVRs and a FVR wereappl ied s imi lar to prev ious chemica l c lean ing app l ica tions. Once b lowdow n was complete , af ina l SG purge was per formed w i th a i r a t a ra te o f approx imate ly 600-650 sc fm per SG for

about 45 m inutes to rem ove nox ious fumes pr ior to opening the SG s for fur ther outage tasks.

Process Moni toring. Process moni toring was conducted w i th gas chrom atographsconnected to the M ain Steam l ine. Gas sam ples were co l lec ted a t spec i f ic t ime s through outthe iron step appl icat ion and the ratio of hydrog en to ni t rogen was evalua ted. Using previoustest data and the s i te spec i f ic W-3 Qual i f ica t ion program data , the process was cont ro l ledbased on the H2/N2m olar rat io. This ratio, in conjun ct ion with samp le chem ist ry results, wa sind icat ive o f the need for in jec t ion o f more or less concent ra ted chemica ls based on actua ldepos i t d isso lu t ion versus theoretica l . In -l ine corros ion m oni tor ing was not per formed dur ingthe actua l chemica l c lean ing app l ica t ion. Howe ver , the corros ion response o f the cri tica lmater ia ls o f const ruc t ion, spec i f ica l ly the SA-569/SA-570 eggcrate mater ia l , was determined

based on eggcrate m easure me nts taken pr ior to and fo l low ing the c lean ing app l ica t ion.

Resu lts. A total of 7,000 Ibs (3,175 kg) of i ron, equiva lent to -9 ,7 00 Ibs (4,400 kg) ofdepos i t a s magne t i t e , we re rem oved f rom the s econ da ry s ide o f W-3 S Gs v ia chemica l

c lean ing. An ad d i tiona l 4 ,608 Ibs (2 ,090 kg) o f wet s ludge were rem oved post -c lean ing s ludgelancing and up per bund le flushing. The bulk of the depo s i ts rem oved via chem ica l c leaning

was magnet i te , Fe304 (-96%), only a f rac t ion of n icke l (<2%) and t race amounts were copper ,

chromium , and zinc . A sum ma ry o f the depos i ts is presented in Tab le 5 . V isua l inspect ionfo l lowing the chemica l c leaning revea led tha t s ignif icant ly more depos i t remained in the SGs

than had been observed fo l low ing EPRI /SGOG based c lean ing app l ica t ions o f moderate lyfouled s team gen era to rs . Th e spa ll ing/undissolved de pos i ts were m ore typica l of the resul ts

seen af ter the c lean ing o f heav i ly fou led s team g enerators such as San Onof re . The depos i twas heavy enough to occ lude som e o f the l at ti ce open ings in s eve ra l a rea s . Spa l l ed depos i t

" f lakes" were a lso pres ent in severa l a r ea s on the lower tube sup port s t ruc tures . Th e depos i tload ing was heav iest on the 1st and 2 nd tube suppor ts and l ightened as e levat ion increased.

The dist r ibut ion of the res idual d epos i t w as d iametrica lly oppo sed to the n ormal fouling pa t te rn

of these SGs, which ind icated that the mater ia l was re leased dur ing c lean ing and set t led ont he lower po r tions o f the SG s . The s ludge rema ining in the SG s was s amp led and ana lyzed

and found to be composed of hemat i te w i th magnet i te and fer r ic ox ide and some copper .

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Based on the composi t ion o f the res idua l s ludge, a comprehens ive root cause ana lys is wasper fo rmed and a h igh t empera tu re ox ide r educ t i on s t ep implemented dur ing s t a r t up t o

chemica l ly reduce the hemat i te and s imi lar const i tuents remain ing in the SGs and mi t igate anyl ong-t e rm de t r imen ta l e f f ec t s t hey m ay have on t he A l loy 600 t ub ing .

Corros ion resu l t ing f rom the chemica l c lean ing app l ica t ion based on eggcratemeasurements taken before and a f ter the c lean ing app l ica t ion were h igher than expectedbased on test ing, but below the l imits set for the cr i t ical eggcrate components present in the

SGs as shown in Tab le 6 . Pre-c lean ing measurem ents were per formed on the 1st eg gcr ate inSG #1 in the spr ing 1999 outage us ing safe ty- re la ted gauges. A l l me asured areas werescraped to the base meta l to ensure the most accurate meas urem ent was obta ined. Post -c lean ing measurements were per formed at the 1st eggcrate in both SG s af ter m easurem entsin SG #1 indicated a total corrosion o f 12.9 mils. As-b ui l t d im ens ions w ere used in SG #2 todeterm ine the total corrosion o f 6.0 mils in SG #2. The sig nif icant di fferenc e in corrosionbetween the two SGs most l ike ly was the resu l t o f excess EDTA, the che la t ing agent used inthe i ron rem oval s tep so lvent formula t ion, due to an overest imat ion o f the d epos i t load ing thatresulted in the lower port ions of SG #1 being exposed to concentrated solvent .

Deta i led v isua l examinat ions o f the SGs were per formed to assess the e f fec t iveness o f

the chem ica l c lean ing. Overa l l the c lean ing and subse quen t s ludge lanc ing operat ions wereef fect ive in removing the bulk of the deposits f rom the internal surfaces and dissolv ing theavai lable depo sits. Inspec t ions fo l low ing the in it ia l s ludge lancing opera t ion in the lower leveleggcrates revea led some amount o f depos i ts w i th var ied morphology, f lake, loose ly adherentand packed depos i ts . Thes e depos i ts var ied in co lor f rom orange to dark gray. Other areasof the SGs a lso exh ib i ted s imi lar depos i t Ioad ings and character is t ics inc lud ing the upperhor izonta l tube sur face runs. Howe ver , upper bundle f lush ing and add i tiona l s ludge lanc ingremoved most o f these depos i ts a l though some mater ia l was s t i l l adherent to the tubes. Auni form s ludge p i le approx imate ly 1-2" in depth was observed on the tubesheet a long w i thsom e spa l led dep osits in the lat t ice bars of the 1st TS P alon g the div ide r lane and inn er bundlereg ion. Exam ples o f som e of the areas o f the W-3 S Gs are g iven in F igure 11 through F igure

14. Addi t iona l v isua l inspect ions were recom me nded dur ing subsequ ent outages to determinei f the app earanc e o f the SG var ies a f ter a cyc le o f operat ion.

Palo Verde N uclear Generat ing S ta t ion Uni t I (PVN GS -1)

Cleaning Appl ica tion. The PVNGS -1 chem ica l c lean ing was in i tia ted on Septem ber 29 ~and com pleted o n Septem ber 30 h, 2002. It cons is ted o f an inh ib i ted H igh Tempe ratureChemica l C lean ing (HTCC)i ron removal s tep fo l lowed by low and fu l l vo lume r inses and af ina l EPRI /SG OG pass ivat ion app l ica tion us ing p lant prov ided heat. The chem ica l c lean ingproces s was appl ied in paral le l in the two SG s. The H TC C step was appl ied to a f inal level~406" above the tubeshee t . In jec t ion o f the HTCC so lu t ion was ach ieved v ia the p lant

b lowdown heat exchange r . Once the p lant reached M ode 4, the SGs were com plete ly dra inedand f il led from the bottom wi th pre-mixed so lvent . The app l ica t ion tempe rature wasmainta ined a t approx imate ly 290°F (143°C). The so lvent was formula ted to the des i redconcent ra t ion pr ior to in jec tion in to the SGs. Som e so lvent mix ing was ach ieved w i th so lventbo i l ing v ia vent ing the SGs in termi t tent ly through the p lant a tmospher ic dump va lves (ADVs)for the durat ion o f the HT CC appl ica tion. The ap p l ica tion t ime of the HTC C step was l imi ted to

10 hours at >28 5°F (14 1°C) pe r the or ig inal qual i f icat ion prog ram . Fol low ing the HTC C step, aser ies o f LVRs and a FVR were app l ied s imi lar to prev ious chemica l c lean ing app l ica t ions.

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Fo l low ing the FVR, the SGs were d ra ined and b lowdo wn conduc ted . The SG s were thentu rned ove r to the s it e fo r t he EP RI /SGO G pass iva ti on app l i ca ti on . The pass iva t ion wasappl ied a t a leve l s ign i f icant ly h igher than the chemica l c lean ing app l ica t ion us ing over 45,000gal lons o f so lu t ion .

P rocess Mon i to r ing . P rocess mon i to r ing was conduc ted w ith chem is t ry samp lesco l lec ted per iod ica l ly f rom the SG s. The pr ima ry cons t i tuen ts mon i tored inc luded the f reeE thy lened iamine te t raace t i c Ac id (EDTA) concen t ra t i on , t he d i sso lved i r on concen t ra t i on , and

the hydraz ine (N2H4) conc ent ra t ion . A l l p rocess dec is ions were base d on these resu l ts . Eachparamete r t r ended as expec ted based on the 1995 chemica l c lean ing da ta and the es t ima teddepos i t load ing.

Resu l ts . A to ta l o f 6 ,311 Ibs (2 ,863 kg) o f iron, equ iva len t to ~8,72 2 Ibs (3 ,856 kg) o fdepos i t as magne t i t e , were removed f rom the secondary s ide o f PVNGS-1 SGs v ia chemica lc lean ing. An add i t iona l 10 5 Ibs (48 kg) o f we t s ludge were remo ved post -c lean ing s ludg elanc ing . The bu lk o f t he depos i ts removed v ia chemica l c lean ing was magne t it e , Fe304(~96%) w i th on ly tr ace am oun ts o f o the r cons t it uen ts . A su mm ary o f the depos i ts i s p resen tedin Tab le 7 .

Cor ros ion resu l t ing f rom the chemica l c lean ing app l ica t ion was based on the cor ros ionresu l ts o f the f irs t PVNG S-1 chem ica l c lean ing a pp l ied in 1995 and are sho wn in Tab le 8 .These co r ros ion va lues a re cons ide red conserva t i ve fo r t h i s app l i ca t i on s ince the p rocessapp l i ca ti on was mod i f i ed f rom the 1995 c lean ing w i th the remova l o f the EPR I /SGO G c rev ice -c lean ing s tep that resu l ted in add i t iona l cor ros ion in the lowe r reg ions o f the SG s. In add i t ion ,the amoun t o f depos i t p resen t i n t he s team genera to rs was s ign i f i can t l y l ower and requ i red alower che la t ing agen t concen t ra t ion . Th is impac ts the co r ros ion response s ince a g rea te rdep os i t load ing resu l ts in a h igher to ta l cor ros ion resp onse. Edd y cur rent tes t ing and v isua li nspec tion were conduc ted fo l low ing the chemica l c lean ing app l i ca ti on . The qua l i ty o f t he ECTsigna ls was repor ted as much improved and the v isua l inspect ion showed l i t t le to no depos i ts

remain ing in the SGs as dep ic ted in F igures 15 and 16.

N e c k a r w e s t h e i m N u c l e a r G e n e r a t io n S t a ti o n G e r m a n y ( G K N 1 )

S ince ten app l i ca ti ons o f the n on- inh ib i ted h igh tempe ra tu re c hem ica l c lean ing p rocesshave been pe r fo rmed s ince 1998 , w i th the excep t ion o f t he W-3 c lean ing pe r fo rmed in theUni ted Sta tes, on ly the m ost recent app l ica t ion a t GK N 1 w i l l be descr ibed in deta i l. Asummary o f t he resu l t s o f t he non- inh ib i t ed chemica l c lean ing depos i t r emova l i s g i ven in

Tab le 9 .

C lean inq Appl ica t ion. GKN 1 is a three- loop un i t . S ludge inventory eva luat ions revea ledtha t approximately 3 ,748 Ibs (1 ,700 Kg) of magnet i te per SG with --2% cop per w ere to be

expec ted fo r t he c lean ing , hence , an i r on s tep w i th a subsequen t copper s tep were p lanned .The i ron s tep w as com pleted on M ay 31 st, 2002 af ter an appl ica tion durat ion of 23 ho urs . The

SGs were then coo led down and d ry ing ins t i t u ted in p repara t i on fo r t he copper remova l s tep .The copper s tep w as pe r formed and comple ted on Jun e 4 th, 2002 . Th e chem ica l c lean ing ta sk

f rom s tep to tea rdown was on ly 18 days .

The i ron s tep was in it ia ted du r ing shu t down o f t he p lan t and was pe r fo rmed a t 320 -347°F (16 0-175 °C). To mainta in suff ic ient hea t s ink capaci ty , i t w as ne ce ssa ry to c lean the

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SGs in ser ies . Chemica ls were in jec ted v ia h igh pressure pumps, se tup in the aux i l ia rybu i l d ing , t h rough the b lowdown l i nes o f t he SGs. The chemica ls requ i red to d i sso lve thes ludge inventory were in jec ted in four s teps. The chemica ls were s tored in the yard and wereprov ided to the h igh pressure pumps w i th a booster pump. A f ter c lean ing the f i rs t generator ,the spent i ron so lvent s tayed in generator to act as a heat s ink for the o ther SGs. A f tercomple t ion the i ron s tep in a l l th ree generators , the pr imary c i rcu i t was coo led down to lessthan 212°F (100°C) and dra ined. A f ter dra in ing, the generators were dr ied w i th a i r supp l iedf rom a compresso r l oca ted in the ya rd . Once d ry ing was comp le ted the copper s tep was

per formed a t less than 140°F (60°C) . To min imize waste vo lume, the copper s tep for a l l th reegenera to rs was pe r fo rmed w i th on ly one genera to r vo lume tha t was pumped f rom one SG tothe o ther .

Process Moni tor ing. Dur ing the i ron s tep, process moni tor ing was per formed w i thchem ist ry sam ples taken a f ter each chem ica l in jec t ion, i ron, f ree and to ta l EDT A as wel l aspH were de te rm ined in the l i qu id samp les . I n add i t i on , gas samp les were taken to de te rm ineH2/N2 ra t io that ind icates whether s ludge d isso lu t ion or base meta l a t tack preva i ls . Dur ing thecopper s tep , copper was ana lyzed in l i qu id samp les and the copper s tep was te rm ina ted a f te rthe coppe r va lue reached sa tu ra ti on .

Resu l ts . W i th the chem ica l c lean ing o f the th ree SG s 8 ,342 Ibs (3 ,784 k g )o f i ronco r respond ing to 11 ,523 Ibs (5 ,227 Kg) o f magne t i t e , were removed . The copper s tepd isso lved an add i t iona l 126 Ibs (71 Kg) o f copper . The tubesheet s ludge was suf f ic ient lysof tened to a l low successfu l fo re ign mater ia l removal and s ludge lanc ing operat ions. A f terrestar t o f the p lant , the expec ted increa se in heat t ransfer was rea l ized. An ap prox im ate 1 .7bar i nc rease o f secondary s ide p ressu re was ob ta ined w i th abou t a 0 .5°C lower p r imary s idetempera tu re .

C O N C L U S I O N

Through qua l i f i ca t i on and eva lua t ion , any t ype o f SG des ign con f igu ra t i on can be chemica l l y

c l eaned w ith a chem i ca l c l ean i ng p r o ces s des i gn ed t o m e e t t he ob j ec t ives o f t he u t il it y and t oensure op t imum per fo rmanc e and l if e o f t he SGs. Very d if f e ren t SG des igns , a W es t inghouseMode l 51 ( Sa l em - 2) , a B& W O T SG ( D av i s - B es se ) , a C om bus t i on Eng i nee r i ng 3410 ( W- 3) , aC o m b u s t i o n E n g i n e e r in g S y s t e m 8 0 ( P V N G S - 1 ) a n d m u lti pl e R u s s i a n t y p e W E R ( P a k s 2 , 3 ,

4 ,1 ) spec i f i c CANDU type (P icke r ing 5 ; 6 ; 8 ) and S iemens t ype (Grohnde , B rokdor f , GKN 1 )SG s have been c l ean ed succes s f u l ly . Each p r o ces s app l ica t ion w a s i ndependen t l y qual if iedand unique to the spec i f ic s i te b as ed on the u ti li ty 's objec t ives for the c hem ical c leaning s .Che mica l c lean ing, as i t wa s or ig ina l ly des ign ed, has ass is ted the se u t i li t ies in extend ing thel ife of the SG s throu gh to rep lace m en t or end of p lant li fe .

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R E F E R E N C E S

• King, RK and JF Rem ark, "Chem ical Cleaning of the S alem U nit 2 S team Generators,"Proceedings: Steam Generator Sludge Management Workshop,TR-114854, Apri l2000.

111 Evans, SE, et. al., "Davis-Besse C hem ical Cleaning - Fina l Re port," Frama tomeDocument 51-50082-00, M ay 200 0, PRO PRIETARY .

111 Evans, SE and JF Rem ark, "Waterford-3 Che mical Cleaning Final Report," FramatomeDocument 51-5010032-00, February 2001, PROPRIETAR Y.

D Evans, SE and PA Sherburne, "Palo Verde Unit 1 HTC C Chemical C leaning FinalReport," Framatome Document 51-5021038-00, O ctober 2002, PR OPR IETARY.

1 Knol lmeyer, PM, and CD Palm er, "PV-1 Che mica l Cleaning Q ua l i f icat io n- Summ aryReport , " Framatome Document 51-1234954, March 1995, PROPRIETARY.

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T A B L E 1

S A L E M U N I T 2 C H E M I C A L C L E A N I N G D E P O S I T R E M O V E D

V A L U E I N P O U N D S ( K IL O G R A M S )

A m o u n t R e m o v e d A sP r o c e s s S t e p

I ron

Crev i ce

C u / P ass

Tota l s

T O T A L C C

S l udge Lanc i ng

G R A N D T O T A L

M a g n e t i te , F e 3 0 4L b s ( K g )

11 , 019( 4 , 998 )

1,711( 776 )

14(6 .4)

12 , 744( 5 , 781 )

Ni c k e l O x i de , N i OL b s ( K g )

182(83)

38(17)

1(0.5)

221( l o o )

Z i n c O x i d e , Z n OL b s ( K g )

6(2 .7)

1(0 .5)

0( o )7

(3.2)13,264( 6 , 017 )

C o p p e r , C uL b s (K g )

13(5.9)

0( o )

2 79( 127 )

29 2( 132 )

1,233( 559 )

14,497( 6 , 576 )

Mater ia l

A-285 Gr. C

A-285 Gr. C

SA-533 Gr. A

S MA W

A-508

H A Z(SA-

533A / S MA W8018C )

A-53 Gr. B

T A B L E 2

S A L E M U N IT 2 C H E M I C A L C L E A N IN G C O R R O S I O N A L L O W A N C E S

Conf igurat ion

V A L U E S I N M I L S ( I ~ M )

Diametral Increase (TSPs 1,2,3)

Diametral Increase (TSPs 4,5,6)

7 h TSP Sur face (per s ide)

Genera l

Genera l

Genera l

Genera l

Genera l

Cor r os i onA l l ow a nc e s

Mils ( I~M)

8.6(218.4)

6 .6(167.6)

3 .3(83.8)

28(711.2)

28(711.2)

28(711.2)

28(711.2)

28(711.2)

28(711.2)

28

Aler t L imi ts a)

Mils ( I~M)

7.5(190.5)

5 .0(127.0)

3 .0(76.2)

15(381.0)

15(381.0)

15(381.0)

15(381.0)

15(381.0)

15(381.0)

15A-576

Genera l

Genera l[ (711.2 ) (381.0) (9.4)

(a)Alert L imi t was typical ly 5 0-75% of the corrosion al lowan ce exc ept wi th respect to the 7 n TSP thickness.(b)Free corrosion coupons we re included in the mon i tor ing scenar io to co mpa re these mater ials ' response to previous data.

A v e r a g eCor r os i on / Ra nge

O bs e r v e dMils ( I~M)

0.38-0.52(9.6-13.2)

0.17-0.23(4.3-5.8)

0.23-0.31(5.8-7.9)1.86-2.82

(47.2-71.6)3.24

(82.3)3.37

(85.6)0 . 30 (b)

(7.6)

0.34 (b)(8.6)

0.36 (b)(9.1)

0.371 ))(9.4)

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T A B L E 3

D A V I S -B E S S E C H E M I C A L C L E A N IN G D E P O S I T R E M O V E D

V A L U E S IN P O U N D S ( K I L O G R A M S )

Step

Iron

O T S G

2A E1BW

Tota l CC Both

S ludgeLanc ing

Grand Tota l

Magnet i te ,

Fe304Lbs (K g )

2 ,430 (1 ,102)2 ,550 (1 ,157)

4 ,980 (2 ,259)

A m o u n t R e m o v e d A s

Nicke l Oxide , " Z inc Oxide ,N iO

Lbs (Kg)

59 (27)60 (27)

119 (54)

Z n OL b s (K g )

5 (2.2)4 (1.8)

9 (4.0)

928 (421)

6 ,036 (2 ,738)

Tota l Deposi tLbs (Kg)

2,494 (1 ,131)2 , 6 1 4 ( 1 , 1 8 6 )

5 , 1 0 8 ( 2 , 3 1 7 )

T A B L E 4

D A V I S -B E S S E C H E M I C A L C L EA N I N G C O R R O S I O N A L L O W A N C E S

V A L U E S I N M I L S ( I ~ M )

Material

SA-515 Gr . 70

AIS1-1015

G enera l

G ene ra l

Conf igurat ion

T ube S uppo r tP lates

F ree C oupons

Area Rat io (1:1 )

Area Rat io (8:1)

G rounded(Galvan ic )

F ree C oupons

Area Rat io (8:1)

G rounded(Galvan ic )

F ree C oupons

Corros ionA l l o wa n c e s

Mils ( l~ i )

9.0 (a)(228.6)

9.0 (a)(228.6)

9.0 (a)(228.6)

9.0{a~(228.6)

9.0 (a)(228.6)

10(254.0)

10(254.0)

10(254.0)

10(254.0)

A v e ra g eC o r ro s i o n / R a n g e

Ob s e rv e d

M ils ( I ~ M )0.54-0 .569(13.7-14.5)

0 .072-0 .101(1 .83-2 .57)

0 .339-0 .352(8 .61-8 .94)

0 .866-0 .912(22.00-23.16)

1 .087-1 .194(27.61-30.33)

0 .098-0 .146

10SM AW Gene ra l A rea Rat ion (8 :1) (254.0) (38 .48-39.83)

G rounded 10 3 . 643 -4 .052(Galvan ic ) (254.0) (92 .53-102.92)

{a~his is the corrosion allowance or the increase n radial clearance of the tu be supp ort plates hat arefabricated from S A-515 Gr. 70 material. The diametral corrosion allowance s 18.0 m ils (457.2 pM).(b) Galvanic couple s Inconel o Carbon Steel.

(2 .49-3 .71)

0 .943-0 .960(23.95-24.38)

2 .278-2 .546(57.86-64.67)

0 .159-0 .207(4 .04-5 .26)

1 .515-1 .568

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T A B L E 5

W A T E R F O R D U N IT 3 C H E M I C A L C L E A N IN G D E P O S I T S R E M O V E D

V A L U E S IN P O U N D S ( K I L O G R A M S )

S t e p

Iron

C o p p e r

R inse

To ta l CC

S ludge Lanc ing/Uppe r Bund le

Flush

Grand To ta l

M a g n e t i t e ,

Fe304L b s ( K g )

6 ,797 (3 ,083 )

188 (85)

1.1 (0.5)

C o p p e r ,

C uL b s ( K g )

32.4(14.7)

28.3(12.8)

N i c k e l

O x i d e , N i O

L b s ( K g )

177 (80)

5.1 (2.3)

Z i n c O x i d e ,

Z n O

L b s ( K g )

0 .8 (0 .4)

o . 1 ( o . o 5 )

7 ,234 (3 ,281 )

4 ,608 (2 ,090 )

11 ,842 (5 ,371 )

C h r o m i u m

O x i d e ,

Cr203

L b s ( K g )

4.0 (1 .8)

T o t a

L b s ( K

6 ,979(3 ,166

226 (10

29 .4(13.3

T A B L E 6

W A T E R F O R D U N IT 3 C H E M I C A L C L E A N I N G C O R R O S I O N A L L O W A N C E S

V A L U E S IN M I L S (# M )

Eggcrate

7 & Batwings

10

Corrosion Al lowancesMi ls (pa )

17.0(431.8)

16.0(406.4)

15.0(381.0)

14.0(55.6)13.0

(330.2)12.0

(304.8)10.0

(254.0)8.0

(203.2)7.0

(177.8)7.0

( 1 7 7 . 8 )

SG #1 CalculatedCorrosion a)

Mi ls (FM)12.9

(327.7)

10.0(254.0)

10.0(254.0)

5.8(147.3)

6.2(157.5)

6.0(152.4)

5.7(144.8)

5.6

(142.2)3.3

(83.8)2.7

(68.6)

SG #2 Calculated_(a)

Cor ros io .Mi ls (pM)

. . . .

6.0(152.4)

6.0(152.4)

6.0(152.4)

6.0(152.4)

5.9(149.7)

5.7(144.8)

5.5(139.7)

5.2

(132.1)3.7

(94.0)2.4

(61.0)

(a)Calculated corrosion based upon mea suremen ts taken dur ing p re- and post-cleaning visual inspections.

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T A B L E 7

P A L O V E R D E U N IT 1 H T C C C H E M I C A L C L E A N I N G D E P O S I T S R E M O V E D

V A L U E S IN P O U N D S ( K IL O G R A M S )

S t e p

HTC C ( I ron)Rinse

Total CCSludge Lancing

Grand Tota l

Magnet i te , Fe304L b s ( K g )

8,722(3,956)514 (233)

N i c k e l O x i d e , N i OL b s ( K g )

12 2 ( 55)

9,359 (4,245)1 0 5 ( 4 8 )

9,464 (4,293)

Z i n c O x i d e , T o t a l

Z n O L b s (K g )L b s ( K g )1 (0 .45) 8 ,845 (4 ,0 .12)

- - 514(233)

T A B L E 8

P A L O V E R D E U N IT 1 H T C C C H E M I C A L C L E A N IN G C O R R O S I O N A L L O W A N C E S

V A L U E S I N M I L S ( # M )

M a t e r i a l

SA-533 G r. A

AIS1-1018

E7018 SMAW

SA-106 Gr. B

A-240 Type 405

A-176 Type 409

C o m p o n e n t

Shell

Internals

Pressure Boundary

Nozzles

Flow Distribution Plate

Eggcrates

C o r r o s i o nA l l o w a n c e s

Mils ( I~M)

61.5 (1562)

58.8 (1494)

60.7 (1542)

26.9 (683)

3.455 (87.8)

i ¸

A v e r a g e C o r r o s i o n

1.001 (25.4)

3.692 (93.8)

1.786 (45.4)

1.115(28.3)

0.045 (1.1)

0.045 (1.1).455 (87.8)

Mils ( I~M),, ,

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TABLE 9

DEPOSITS RE MO VAL OF NO N-INHIBITED H IGH TEMPERATURE CLEANING PRO CESSOUTSIDE OF US VALU ES IN PO UND S (KILOGRAM S).

Unit (Country)

Paks 2 (Hungary)

Grohnde Germany

Brokdorf (Germa ny)

Paks 3 (Hungary)

Paks 4 (Hungary)

Paks 1 (Hungary)

Picker ing Uni t 5

(Canada)

Picker ing Uni t 6

(Canada)Picker ing Uni t 8

(Canada)

N e c k a r w e s t h e i m

(Germany)

Year

1998

1998

1999

1999

2000

2000

2001

2001

2002

2002

Number SG's

12

12

12

M a g n e t i t e

Lbs (Kg)

9,109 (4,132)

7,616 (3,455)

11,611 (5,257)

11,490 (5,212)

13,957 (6,331)

19,629 (8,904)

2,987 (1,355)

4,307 (1,954)

4,938 (2,240)

11,523 (5,227)

C o p p e r

Lbs (Kg)

n . a

n . a

n . a

n . a

n . a

n . a

507 (230)

414(188)

1,109 (503)

156 (71)

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FIGU RE 1 - Ph o to g r a p h o f Fo u rth TSP in Sa le m- 2 SG - 2 3 B e fo r e C le a n in g

F IGURE 2 - Ph o to g r a p h o f Fo u r th TSP i n Sa le m- 2 SG- 2 3 A f t e r C le a n in g

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FIGU R E 3 - Pho togra ph o f Seven th T SP in Sa lem-2 S G-23 P r i o r t o C lean ing

F I G U R E 4 - P h o t o g r a p h o f S e v e n th T S P in S a l e m - 2 S G - 2 3 A f t e r C l e a n in g

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F I G U R E 5 - P h o t o g r a p h o f S i xt h T S P in D a v i s - B e s s e S G 2 A E P r io r t o C l e a n i n g

. . . . . . !~ , , ~ ! , . . ~ Y! ! i l

F I G U R E 6 - P h o t o g r a p h o f S i xt h T S P in D a v i s - B e s s e S G 2 A E A f t e r C l e a n i n g

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F IGURE 7 - Pho tog raph o f F i f t h TSP Crev i ce i n Dav is -Besse SG 2AE Be fo re C lean ing

F IGUR E 8 - Pho tog raph o f F i ft h TSP Crev i ce in Dav is -Besse SG 2 AE A f te r C lean ing

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FIGURE 9 - Photograph o f F if th TSP C rev ice in Dav is-Besse SG 1BW Before Clean ing

FIGURE 10 - Photograph o f F if th TSP Crev ice in Dav is-Besse SG 1BW A f ter C lean ing

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. . . . . . . . . . . . . . . . . . . . . . . . . . . ' ~ ; ~ s ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . .. . : . . . . . . : : .~ . ~- z :: :; : : : : :: : : :: : : :: : : :: : : :: : : :: : : :: : :. . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . : i : ~ : , : : : ~ : ~ : ~ : : . : i : : i i : : . : ~ : ~ : ~ : : : ~i ~ . ~ . ~ . : , : , ~ , ~ : : : ~ : # : ~ : : : : . : : . ? ?~ 2 2 ~ ~ : : ~ g ~ } ~ { ~ : : ~ : : ~ : : ~ { ~ < ~ { ~ { ~ > ~ : : . :: : > ~ G ~ : ~ : ~ : ~ ~ : ~ . . . . . . ~ : i ~ . . .: ~ : : :~ : ~

( W E : w o r k i n g e l e c t r o d e , R E : r e f e r e n c e e l e c t r o d e )

(a )

i l i i i ii i i i ii i i

(b )

F I G U R E 6 . T h e e q u i v a l e n t e l e c t r ic a l c ir c u it s f o r t h e W C - T il .× A l x N c o a t i n g s y s t e m s :

( a ) W C -T i o. 6A l o .4 N i n l h i m m e r s i o n t i m e , W C - T i o .s A I o .s N a f t e r l h i m m e r s i o n t i m e ;

(b ) W C-Tio .6Alo .4N a f te r 24h immers ion t ime , W C-Tio . s3Alo .47N and W C-Tio .43Alo . s7N a f te r lh immers ion t ime .

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FIGURE 11 - Photograph of 1st TSP Crevice in Waterford 3-2 After Cleaning

FIGURE 12 - Photograph of F i f th TSP Crevice in Waterford SG 3-2 After Cleaning

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. . . .

F I G U R E 1 3 - P h o t o g r a p h o f s e v e n t h T S P C r e v i c e in W a t e r f o r d S G 3 - 2 A f t e r C l e a n i n g

i i i i ~ i ! i i ¸

, ~ i i ~ ! ~ z ~ i ~ i ! i i i i ~ !¸

F I G U R E 1 4 - P h o t o g r a p h o f T e n t h T S P C r e v i c e in W a t e r f o r d S G 3 - 2 A f t e r C l e a n i n g

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FIGURE 1 5 - Photograph of SG1 C old Leg in Palo Verde SG I-1 After Chem ical Cleaning

FIGURE 16 - Photograph of SG1 H ot Leg in Palo Ve rde SG I-1 After Chem ical Cleaning

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