1996 advanced procedures for the ultrasonic examination of narrow gap welds connecting the steam...

7/29/2019 1996 Advanced Procedures for the Ultrasonic Examination of Narrow Gap Welds Connecting the Steam Generator

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14th International Conference on NDE in the Nuclear and Pressurise Vessel Industries,Stockholm, 24-26 September 1996

ADVANCED PROCEDURES FOR THE ULTRASONIC EXAMINATION OFNARROW GAP WELDS CONNECTING THE STEAM GENERATOR TO THE RCS PIPING.

G. Maes, AIB-Vinotte, Brussels, BelgiumM. Lepice, Tractebel Energy Engineering, Brussels, Belgium

Abstract

St eam gener at or r epl acement i s a cur r ent t opi c i n the nucl ear i ndust r ywor l dwi de. I n Bel gi um, st eam generat ors have al r eady been r epl aced i n t hr eeuni t s. I n al l t hr ee cases, ent i r el y aut omated narr ow gap wel di ng wasper f ormed t o connect t he pr i mary nozzl es of t he new st eam gener at or s t o t her eact or cool ant syst em pi pi ng.Nar r ow gap wel ds pr esent a speci f i c met al l ur gi cal gr ai n st r uct ur e. I n spi t eof t he l i mi t ed quant i t y of wel d met al deposi t ed t hi s st r uct ur e candr ast i cal l y af f ect t he capabi l i t y of convent i onal ul t r asoni c exami nat i ont echni ques.I n t he f r amework of i t s ef f ort t o compl y wi t h t he r equi r ement s of Appendi xVI I I of Sect i on XI of t he ASME Code concer ni ng t he qual i f i cat i on of UTpr ocedur es f or i n- ser vi ce i nspecti on, El ectr abel ( t he ut i l i t y) andTr act ebel ( t he A/ E) i ni t i at ed wi t hi n t he ASME XI St eer i ng Commi t t ee,

envol vi ng al so AVN ( t he regul at or y body) and AI B- Vi not t e ( t he AI A) , t hepreparat i on of advanced procedur es f or t he exami nat i on of such narr ow gapwel ds.To provi de a sol i d t echni cal f oundat i on f or t hese procedures, anexper i ment al st udy was conduct ed on several t ypes of nar r ow gap wel ds usedi n Bel gi an pl ant s. Thi s paper shal l pr esent r esul t s concer ni ng t hei nf l uence of i mport ant exami nat i on parameters such as wave type, f r equency,and ref r act ed angl e on the pr opagat i on of ul t r asound t hr ough the consi deredwel ds.Real i st i c cr ack- l i ke f l aws i n r epr esent at i ve t est bl ocks wer e used t oassess t he det ect i on and si zi ng capabi l i t y of newl y devel oped, t wi n- cr ystalt r ansducer s. The enhanced per f ormance i n t erms of si gnal - t o- noi se r at i o andhei ght si zi ng accur acy, obt ai ned t hr ough cust omi zed desi gn usi ng f ocusi ngcryst al s , i s cl ear l y i l l us t r at ed.

To concl ude, t he paper shal l f orwar d gui del i nes as t o t he sel ect i on ofexami nat i on t echni ques f or bot h manuf act ur i ng and i n- servi ce i nspect i on ofst eam gener at or nar r ow gap wel ds, i n r el at i on wi t h t he speci f i c geomet r yand the met al l ur gi cal st r uct ur e of t he consi dered component s. As anexampl e, an out l i ne shal l be pr esent ed of t he exami nat i on pr ocedur esappl i ed dur i ng the st eam gener at or r epl acement of t he Ti hange 1 pl ant i nAugust 1995.


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1. Introduction

St eam gener at or r epl acement i s a cur r ent t opi c i n the nucl ear i ndust r ywor l dwi de. I ndeed, st eam generat or t ubes are known t o be suscept i bl e t o

cor r osi on. Af t er some t i me, mi cr ocr acks may appear i n t he t ubes, andevent ual l y cause l eaks. Tube pl uggi ng or r epai r i ng met hods, such assl eevi ng, can be used t o mai nt ai n t he st r uct ur al i nt egr i t y of t hecomponent . However, i f t oo many tubes have to be pl ugged, t he heat exchangecapaci t y f r om t he pr i mar y to the secondar y ci r cui t wi l l det er i or at e, andaf f ect t he power out put and t he ef f i ci ency of t he uni t as a whol e.Dependi ng on t he r epai r whi ch mi ght be needed i n the l ong t erm, r epl acementof t he st eam gener at or can pr ove t o be t he most cost - ef f ect i ve st r at egy andshoul d enabl e t he mai nt ai ni ng of a hi gher avai l abi l i t y of t he uni t ( 1) .Mor eover, r epl acement of t he st eam gener at or s may of f er a uni queoppor t uni t y t o upr at e t he power of a nucl ear pl ant .At t he repl acement s per f or med i n thr ee Bel gi an pl ant s, Ti hange 1, Doel 3and Doel 4, f ul l y automated GTAW ( gas t ungsten arc wel di ng) narr ow gapwel di ng was used t o connect t he new st eam gener ator t o t he exi st i ng r eact or

cool ant syst em. Compar ed t o convent i onal submerged ar c wel di ng usi ng adoubl e- angl e chamf eri ng, t he amount of wel di ng mater i al and t hus thewel di ng t i me i s dr ast i cal l y r educed. I n addi t i on, a l ow dose r at e can beachi eved.

2. Ultrasonic propagation in narrow gap welds

A t ypi cal pr i mary pi pi ng narr ow gap wel d conf i gur at i on i s shownschemat i cal l y on f i gur e 1 : af t er wel di ng, t he wi dt h i s about 10 mm and thebevel angl e i s r educed t o al most 0. The successi ve wel d r uns are par al l el

t o t he pi pe sur f ace.The consi dered wel ds present a speci f i c met al l urgi cal st r uct ure,char act er i sed by a l ar ge change i n gr ai n or i ent at i on acr oss t he wel d. Sucha st r uct ur e i s known t o af f ect t he pr opagat i on of acoust i c ener gy. Numeri csi mul at i ons usi ng r ay- t r aci ng model s have shown t hat consi derabl edi st ort i on of bot h st r ai ght and angl e beams occur s when crossi ng the wel d .Ampl i t ude l osses of about 40 dB have been pr edi ct ed f or convent i onal shearwave probes, compar ed t o 6 dB f or compressi on waves ( 2) .Addi t i onal di f f i cul t i es ar e i nt r oduced by the var i et y of base mat er i al s t obe wel ded : wr ought and cast aust eni t i c pi pi ng, st at i cal l y cast el bows.

Fig. 1 : Schematical representation of typical primary piping narrow gap weld.


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3. Experimental study

I n t he f r amework of i t s ef f ort t o compl y wi t h t he r equi r ement s of Appendi xVI I I of Sect i on XI of t he ASME Code concer ni ng t he qual i f i cat i on of UT

pr ocedur es f or i n- ser vi ce i nspecti on, t he Bel gi an ut i l i t y El ectr abeli ni t i at ed t he pr epar at i on of advanced pr ocedur es f or t he exami nat i on ofaust eni t i c wel ds of t he react or cool ant system.As f ew r el evant dat a on t he capabi l i t y of ul t r asoni c exami nat i on t echni quesf or pr i mar y pi pi ng narr ow gap wel ds wer e avai l abl e, an experi ment al st udyon r epr esentat i ve t est speci mens was deemed necessary t o pr ovi de a sol i dt echni cal f oundat i on f or t he new exami nat i on pr ocedur es. The st udy ai med atassessi ng t he i nf l uence of i mport ant i nspect i on par amet ers , such as wavet ype, f r equency, and r ef r act ed angl e on t he pr opagat i on of ul t r asoundt hrough nar r ow gap wel ds.

3. 1. Test speci mens

Si x test speci mens wer e made avai l abl e by t he Bel gi an ut i l i t y, al l of t hemr epr esent at i ve of narr ow gap wel d conf i gur at i ons encount ered i n Bel gi anpl ant s. Al l speci mens have ext ernal di ameters of about 900 mm, and wal lt hi cknesses of 75 or 90 mm.Tabl e 1 provi des f ur t her detai l s on t he speci mens and on t he r ef l ect or s.I n two of t he t est bl ocks t he narr ow gap wel d connects a cast t o a wr oughtbase mat er i al , whi l e i n al l ot her bl ocks t wo wr ought base mat er i al s arewel ded t oget her . Ser i es of si de- dr i l l ed hol es ar e pr esent bot h i n t hevar i ous base mat er i al s and i n t he wel ds. To si mul at e f ar - sur f ace cr acks,bot h r ect angul ar and ci r cul ar sl ot s of di f f er ent hei ght s and or i ent at i onswer e machi ned at r eal i st i c posi t i ons i n t he wel d and t he HAZ. The ci r cul arsl ot s are i dent i cal t o t he smoot h and shar p def ects commonl y used i n t hePI SC I I I exer ci ce ( t ype A f l aws) , and wer e manuf act ur ed at t he J RC Pet t enof t he CEC.

3. 2. Equi pment

Manual ul t r asoni c exami nat i on of t he speci mens was per f ormed usi ng ast andar d Kr aut kr mer USK7D f l aw det ect or . Measur ement s f or det ect i on andsi zi ng of cr ack- l i ke r ef l ect or s wer e al so per f or med by aut omat ed ul t r asoni ct est i ng, usi ng a Tomoscan data acqui si t i on syst em and a mot or i zed scanni ngdevi ce.An extensi ve set of ul t r asoni c probes was appl i ed dur i ng the exper i ment alst udy. Tabl e 2 l i st s t he di f f er ent model s, wi t h t hei r nomi nalchar act er i st i cs (measur ed i n car bon st eel ) and t he dept h zone( s) f or whi cht hey have been t est ed. Convent i onal shear wave t r ansducer s were used as

wel l as t wi n- cr yst al compr essi on wave ( TRL) pr obes.The so- cal l ed f ocusi ng TRL t r ansducer s ar e desi gned wi t h cur vedpi ezoel ect r i c el ement s i nst ead of t he more common pl anar el ement s. Thi syi el ds an "opt i cal " f ocusi ng, i n addi t i on t o t he pseudo- f ocusi ng ef f ectgener at ed by t he over l ap of t r ansmi t t er and recei ver beams. Thus, a ver ynar r ow acoust i c beam can be obt ai ned i n a l i mi t ed dept h r ange, i mpr ovi ngbot h t he si gnal - t o- noi se r at i o ( SNR) and t he l at er al r esol ut i on. Fi gur e 2i l l ust r at es t he det ect i on and si zi ng capabi l i t y of t he TS45 1 635t r ansducer ( 45TRL, 1 MHz) on a shar p spar k- er oded sl ot at t he f ar- surf acei n cast austeni t i c base mat er i al : t he cl ear l y resol ved t i p di f f r acti onsi gnal al l ows f or accur at e hei ght si zi ng.


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corner

tip

Fig. 2 : A-scan signal obtained with focusing 45TRL, 1 MHz search unit on far-surfacebreaking crack-like flaw (h = 10 mm) in CCSS test specimen.

3. 3. Dat a r ecor di ng

Al l exami nat i ons of t he t est speci mens wer e conduct ed f r om t he out si desur f ace, scanni ng per pendi cul ar t o the wel d axi s.A f l aw i s consi der ed detect ed i f t he peak echo ampl i t ude exceeds t he noi sel evel est i mated i n a f l awl ess zone of t he test speci men, at t he same dept hr ange. The SNR was determi ned f or each ref l ect or . Measur ement s on si de-

dr i l l ed hol es wer e per f or med t o eval uat e the i nf l uence of t he pr opagat i ont hr ough di f f erent mat er i al s on t he perf or mance of t he exami nat i on, whi l et he det ect i on capabi l i t y f or ser vi ce- i nduced def ect s was assessed onsi mul at ed crack- l i ke def ect s.Fl aw hei ght measurement s f or pl anar sur f ace breaki ng def ect s were r ecor dedwhenever t he t i p di f f r act i on met hod was appl i cabl e.

4. Data exploi tation

4. 1. I nf l uence of t he nar r ow gap wel dTo assess t he i nf l uence of t he wel d st r uct ure and of t he i nt er f aci ng f usi onl i nes, si de- dr i l l ed hol es i n t he heat af f ected zone wer e i nsoni f i ed t hr oughwr ought base mat er i al on t he one hand and t hrough a nar r ow gap wel d on theot her hand ( see f i gur e 3) . The si gnal - t o- noi se r at i o val ues obt ai ned wi t ht he consi der ed exami nat i on t echni ques ar e pr esent ed i n t abl e 3, underi nsoni f i cat i on modes " A" and "B". Al l val ues are aver ages r esul t i ng f r omdat a r ecorded on di f f erent t est speci mens.Even at a l ow exci t at i on f r equency, t he det ect i on capabi l i t y of shear wavet r ansducer s i s dr ast i cal l y af f ect ed by t he crossi ng of t he wel d : sever alr ef l ect or s cannot be det ect ed, and ampl i t ude l osses of at l east 10 dB ar eobser ved on t he ot her s. Thi s conf i r ms t he pr edi ct i ons of t heor et i calmodel l i ng ( 2) .


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Fig. 3 : Insonification modes for the assessment of the influence of the narrow gap weld onultrasonic capability

Compr essi on wave pr obes det ect al l r ef l ector s f or bot h i nsoni f i cat i onmodes. The ampl i t ude l oss whi l e crossi ng t he wel d var i es f r om 4 t o 9 dB.When onl y 1 MHz f ocusi ng TRL t r ansducer s ar e consi der ed, a SNR of at l east22 dB i s observed f or i nsoni f i cat i on t hr ough the wel d. The i mpr ovement oft he det ect i on capabi l i t y compared t o st andard TRL pr obes i s i n t he rangef r om4 t o 15 dB.

4. 2. I nf l uence of t he base mat er i al

Si de- dr i l l ed hol es l ocat ed at t he wel d cent r e l i ne wer e i nsoni f i ed f r om t wo

di f f er ent base mat er i al s, as shown schemat i cal l y on f i gur e 4, t o assess t hei nf l uence on acoust i c ener gy pr opagat i on and det ect i on capabi l i t y. Thesi gnal - t o- noi se r at i o val ues obt ai ned wi t h t he consi der ed exami nat i ont echni ques ar e ment i oned i n t abl e 3, under i nsoni f i cat i on modes "C" and"D". The det ect i on capabi l i t y i n cast aust eni t i c base mat er i al i s equal l ypr esent ed ( i nsoni f i cat i on mode "E") .As gener al l y known, shear wave pr obes ar e not sui t ed f or pr opagat i ont hr ough cast aust eni t i c mat er i al : none of t he r ef l ect or s coul d bedet ect ed. Even f or i nsoni f i cat i on t hr ough wr ought base materi al , poor SNRval ues ar e achi eved on r ef l ect or s i n t he nar r ow gap wel d : 15 dB f or t henear- surf ace r ange, and 10 dB f or t he i nt er medi at e and t he f ar- surf acer ange.The per f or mance of l ow- f r equency TRL t r ansducers i s onl y sl i ght l y af f ect edby t he di f f er ence i n base mat er i al : t he cast base mat er i al gener at es an

average SNR r educt i on of 8 dB. The f ocusi ng 45TRL sear ch uni t f or t he f ar -sur f ace r ange st i l l al l ows f or a SNR of 18 dB t hr ough cast mat er i al .No cl ear i nf l uence of t he ref r act ed angl e coul d be obser ved f or ei t hercompressi on or shear waves.


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Fig. 4 : Insonification modes for the assessment of the influence of various base materialson ultrasonic capability

4. 3. Det ect i on and si zi ng of f ar - sur f ace br eaki ng f l aws

Det ect i on r esul t s obt ai ned on si mul at ed crack- l i ke def ect s f or di f f er enti nsoni f i cat i on modes are pr esent ed i n t abl e 4. For a sur f ace br eaki ngdef ect l ocat ed i n the heat - af f ect ed zone, t he f ocusi ng TRL pr obe det ect st he cor ner r ef l ect i on wi t h a SNR of 17 dB t hrough wr ought base mater i al ,and 10 dB t hrough t he nar r ow gap wel d. A r ef l ector i n t he wel d i s det ectedwi t h a SNR of 19 dB when i nsoni f yi ng t hrough wr ought base mater i al and onl y7 dB when i nsoni f yi ng f r om t he cast si de. I n gener al , i t i s obser ved t hatt he SNR on def ect s l ocat ed near t he wel d i s af f ected by t he pr esence of

ul t r asoni c noi se gener at ed by t he f usi on l i nes.Low- f r equency shear waves at 45 were obser ved t o provi de excel l entdet ect i on capabi l i t y on f ar - sur f ace br eaki ng f l aws i n t he wel d or i n t heheat - af f ect ed zone, but onl y f or i nsoni f i cat i on t hr ough wr ought basemater i al . I ndeed, shear waves at 45 degrees ar e known to generate a moreef f i ci ent cor ner r ef l ect i on t han compr essi on waves.Accur at e hei ght si zi ng of cr ack- l i ke f l aws can onl y be achi eved i n t hepr esence of cl ear l y r esol ved t i p di f f r acti on si gnal s. The capabi l i t y off ocusi ng TRL probes t o generate t hese si gnal s was demonst r ated on bot h castand wr ought st ai nl ess st eel base mat er i al . However , f or f l aws l ocat ed i nt he heat - af f ect ed zone or i n t he wel d mat er i al , no di f f r act i on si gnal scoul d be r esol ved f r om t he obvi ousl y br oadened cor ner echo, an ef f ect mostprobabl y caused by t he wel d st r uct ure.

4. 4. Det ect i on capabi l i t y of st r ai ght beam pr obes

Under cer t ai n condi t i ons, t he narr ow gap wel di ng t echni que can gener at el ack of i nt er r un f usi on def ects,par al l el t o the exter nal sur f ace. As such def ect s cannot be det ect ed byr adi ogr aphi c t est i ng, t her e i s a need f or an ef f ecti ve ul t r asoni c str ai ghtbeam exami nat i on dur i ng manuf act ur i ng i nspect i on ( 3) . Usi ng t he twost r ai ght beam pr obes ment i oned i n t abl e 1, SNR val ues hi gher t han 15 dBwere obtai ned over t he compl ete dept h r ange on 3 mm di ameter si de- dr i l l edhol es l ocat ed i n t he wel d. The det ect i on capabi l i t y of t he pr obe f or t hei nt er medi at e and t he f ar - sur f ace r ange i s cl ear l y i l l ust r at ed on f i gur e 5.


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back wall

SDH

back wall

grain noise

Fig. 5 : Ultrasonic signals obtained with focusing 0TRL, 1 MHz search unit inprimary piping narrow gap weld : A-scan signal on 3 mm diameter SDH at 55 mm

depth (above), and on a flawless region (below).

5. Selection of examination techniques

I n t he f r amework of manuf act ur i ng i nspect i ons of pr i mary pi pi ng wel ds, t het r ansposi t i on i nt o t he Bel gi an cont ext of Sect i on I I I of t he ASME Codedemands a f ul l t hi ckness ul t r asoni c exami nat i on of t he wel d i n addi t i on t ot he r adi ogr aphi c exami nat i on. The exper i ment al st udy di scussed abovecl ear l y demonst r at es t he super i or perf or mance of l ow- f r equency f ocusi ng TRLpr obes, especi al l y f or det ect i on of f l aws t hr ough wel ded or cast mat er i al .However , t he beam f ocusi ng t echni que onl y generat es an i ncr easedexami nat i on sensi t i vi t y i n a l i mi t ed dept h zone ( 4) . Thus, i n or der t oachi eve const ant exami nat i on sensi t i vi t y and suf f i ci ent si gnal - t o- noi ser at i o over t he compl et e dept h r ange several t r ansducer s ar e r equi r ed. Thi spr i nci pl e i s i l l ust r at ed i n f i gur e 6 f or t he angl e beam exami nat i on of apr i mary pi pi ng wel d.


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Examination sensitivity

Fig. 4 : Sensitivity curves of angle beam twin-crystal search units covering the variousdepth ranges

I n Bel gi um, i n- ser vi ce i nspect i ons ar e per f or med accor di ng t o sect i on XI oft he ASME code. For pr i mar y pi pi ng, onl y t he i nner t hi r d of t he wal lt hi ckness i s t o be exami ned. Thi s dept h range i s f ul l y cover ed by t heTS00 1 425 ( st r ai ght beam) and t he TS45 1 635 ( angl e beam) f ocusi ng TRL

sear ch uni t s. I n addi t i on, f or an enhanced det ect i on pr obabi l i t y ofsur f ace- br eaki ng f l aws i n wr ought base mat er i al , t he use of a 45 degr eeshear wave pr obe i s st r ongl y r ecommended.The sel ect i on of exami nat i on t echni ques, as present ed hereabove, i sappr opr i at e f or a st andar d pi pe- t o- pi pe conf i gur at i on, and needs t o beadapt ed f or r eal i nspecti on conf i gur at i ons. Fi r st of al l , t he ext er nalsur f ace of st eam gener at or pr i mar y nozzl es i s coni cal . Ther ef or e, t omai nt ai n the opt i mal 45 degr ee i nci dence angl e between the acoust i c beamand a sur f ace- br eaki ng pl anar def ect , t he nomi nal r ef r act ed angl e of t hef ar - sur f ace t r ansducer s r equi r es to be modi f i ed. Second, t he mechani calmat chi ng of a new st eam gener at or t o the exi st i ng react or cool ant systemmay i nt r oduce par t i cul ar exter nal sur f ace condi t i ons i n the nar r ow gap wel dr egi on. I n such cases, al t er nat i ve beam angl es may be r equi r ed f or near -sur f ace or i nt er medi at e zone, i n or der t o i ncrease the r esul t i ng i nspect ed

vol ume. I n f act , an opt i mi zed scanni ng schedul e i s prepared f or each wel dconf i gur at i on .Exami nat i on pr ocedur es desi gned accor di ng t o thi s pr i nci pl e have beenappl i ed dur i ng the Ti hange 1 and Doel 4 st eam generat or r epl acement s.Dur i ng t he qual i f i cat i on phase, t he hi gh det ect i on capabi l i t y of t heexami nat i on method was cl ear l y demonst r ated on a repr esentat i ve testsampl e : a number of f ai r l y smal l l ack of i nt er r r un f usi on t ype i ndi cat i onswere detected and conf i r med af t erwards by dest r uct i ve exami nat i on of t hesampl e.


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6. Conclusions

An exper i ment al st udy on ul t r asoni c exami nat i on capabi l i t y i n var i ouspr i mar y pi pi ng nar r ow gap wel d conf i gur at i ons l ed up to t he f ol l owi ng

r esul t s : l ow- f r equency ( 1 MHz) f ocusi ng TRL sear ch uni t s demonst r ate an excel l ent

gener al det ect i on perf ormance : t he SNR i s al most unaf f ected by t he wel dstructure.

al l f ar - sur f ace br eaki ng f l aws ar e r el i abl y det ect ed by TRL pr obes, whi l eshear wave t r ansducer s are ef f i ci ent t hr ough wr ought base mat er i al onl y.

f ocusi ng TRL pr obes can i n some cases gener at e t i p di f f r act i on si gnal sal l owi ng f or accur at e hei ght si zi ng of crack-l i ke def ects.

I ndust r i al exami nat i on pr ocedur es were pr esent ed f or manuf act ur i ng andi n- ser vi ce i nspect i on of nar r ow gap wel ds, pr ovi di ng const ant sensi t i vi t yover t he compl ete dept h range whi l e scanni ng f r om t he out si de sur f ace onl y.The consi dered procedures can be appl i ed manual l y as wel l as by mechani sedi nspect i on.

7. Acknowledgements

Most of t he work present ed i n t hi s paper was sponsor ed by the ASME XISt eer i ng Commi t t ee whi ch i nvol ves El ect r abel ( t he ut i l i t y), Tr act ebel ( t heA/ E) , AVN ( t he r egul at or y body) and AI B- Vi not t e ( t he AI A) .

8. References

1. Ph. Somville, P. Hernalsteen, R. Houben, "Steam Generator Replacement as a Part of a General ProblemManagement Process", Spec. Meeting on Operating Experience with Steam Generators, Brussels (Belgium),September 1991

2. J. A. Ogilvy, "The Influence of Austenitic Weld Geometry and Manufacture on Ultrasonic Inspection ofWelded Joints", British Journal of NDT, May 1987

3. B. Brion, "Le Contrle Ultrasons des Soudures TOCE des Tuyauteries Primaires", RGN, September-October 1994

4. G. Maes, M. Delaide, Ph. Dombret, "On the Use of the Ultrasonic Beam Focusing Technique", 11th Int.Conference on NDE in the Nuclear and Pressure Vessel Industry, Albuquerque (NM), April 1992

5. M. Lepice, J-P. Litard, "Belgian Response to ASME XI Requirements", BELGATOM, 2nd InternationalConference, Brussels (Belgium), May 1995


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Table 1: Test specimens and reflectors.

SPECIMEN BASEMATERIAL

WELD REFLECTORS

064/SN2Doel 3

WSS / WSS narrow gapSIEMENS

side-drilled holes (=3.0 mm) in WSSrectangular slot (h =2.5 mm) in weld

068/SN3Doel 3

WSS / CSS narrow gapSIEMENS

side-drilled holes (=3.0 mm) in WSS and CSS

DOEL4SGRDoel 4

WSS / CSS narrow gapSIEMENS

side-drilled holes (=4.8 mm) in WSS, in CSS, in HAZ and in weldrectangular slot (h =10.0 mm) in weld

TOCE1Tihange 1

WSS / WSS narrow gapFRAMATOME

side-drilled holes (=3.0 mm) in WSS and in weldmilled notch (1.5 x 4 mm)

TOCE3Tihange 1


type A circular slots (h =5.0, 7.5 and 10.0 mm) in WSS, in HAZ and in weld

TOCE5Tihange 1


type A circular slots (h =7.5 and 10.0 mm) in WSS, in HAZ and in weld

Table 2 : UT transducers (note : characteristics are measured in carbon steel).

PROBE WAVETYPE

PROBE TYPE HOUSINGWxLxH

FREQ ANGLE DEPTH ZONE

MSEB-2E L TRL 20x45 mm 2 MHz 0 near-surface

TS00 1 425 L TRL focused 50x40x38 mm 1 MHz 0 intermediate / far-surfaceST70 2 121 T Single crystal 17x29x22 mm 2 MHz 70 near-surface

TS70 2 220 L TRL 30x30x31 mm 2 MHz 70 near-surfaceTS60 1 445 L TRL focused 50x40x38 mm 1 MHz 60 near-surfaceTS45 1 425 L TRL focused 50x40x38 mm 1 MHz 45 intermediateTS60 1 520 L TRL 50x50x38 mm 1 MHz 60 intermediate / far-surfaceWB45-N1 T Single crystal 32x55x50 mm 1 MHz 45 intermediate / far-surface

TS45 1 621 L TRL 60x60x45 mm 1 MHz 45 far-surfaceTS45 1 635 L TRL focused 60x60x45 mm 1 MHz 45 far-surfaceWB60-N1 T Single crystal 32x55x50 mm 1 MHz 60 intermediate / far-surface

Table 4 : Signal-to-noise ratio values of corner reflections obtained on realistic far-surface breaking planar flaws for variousinsonification modes (Remark : "ND" means that the reflector was not detected, whereas "-" means that nomeasurement was performed).

INSONIFICATION MODE

PROBE TYPEA

IN WSS (HAZ)THROUGH

WSS

B

IN WSS (HAZ)THR. WELD

C

IN WELDFROM WSS

D

IN WELDFROM CSS

E

IN CSSTHROUGH CSS

45T, 1 MHz 24 dB 12 dB 19 dB ND ND

45TRL foc., 1 MHz 17 dB 10 dB 19 dB 7 dB 10 dB


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Table 3 : Signal-to-noise ratio values obtained for various angle beam transducers and insonification modes (Remark : "ND" means that thereflector was not detected, whereas "-" means that no measurement was performed).

INSONIFICATION MODE

DEPTH ZONE PROBE TYPEA

IN WSSTHROUGH

WSS

B

IN WSSTHR. WELD

C

IN WELDFROM WSS

D

IN WELDFROM CSS

E

IN CSSTHROUGH CSS

70T, 2 MHz 26 dB ND 15 dB ND ND

NEAR-SURFACE

(0 - 20 mm)

70TRL, 2 MHz 21 dB 12 dB 13 dB ND 14 dB


45T, 1 MHz 28 dB ND 10 dB ND ND

INTERMEDIATE 60T, 1 MHz 19 dB ND 10 dB ND ND

(20 - 40 mm)45TRL foc., 1 MHz 26 dB 22 dB 18 dB 25 dB 26 dB

60TRL, 1 MHz 22 dB 18 dB 20 dB 11 dB 14 dB



FAR-SURFACE

(40 - 90 mm)60TRL, 1MHz 21 dB 14 dB 16 dB 10 dB 13 dB

45TRL, 1 MHz 22 dB 20 dB 18 dB 13 dB 15 dB


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