CA2158468A1 - Corrosion resistant zirconium alloys usable in water reactors - Google Patents
Corrosion resistant zirconium alloys usable in water reactorsInfo
- Publication number
- CA2158468A1 CA2158468A1 CA002158468A CA2158468A CA2158468A1 CA 2158468 A1 CA2158468 A1 CA 2158468A1 CA 002158468 A CA002158468 A CA 002158468A CA 2158468 A CA2158468 A CA 2158468A CA 2158468 A1 CA2158468 A1 CA 2158468A1
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- CA
- Canada
- Prior art keywords
- zirconium
- alloy
- water
- constituted
- alloys
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C16/00—Alloys based on zirconium
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
- G21C3/02—Fuel elements
- G21C3/04—Constructional details
- G21C3/06—Casings; Jackets
- G21C3/07—Casings; Jackets characterised by their material, e.g. alloys
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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- Engineering & Computer Science (AREA)
- Metallurgy (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Catalysts (AREA)
Abstract
The invention relate to a process for improving the resistance to corrosion in water or zirconium and zirconium alloys.
According to said process, to the zirconium or zirconium alloy is added at least one metallic element able to stabilize the tetragonal phase of zirconia, e.g. 2 to 10% by weight of cerium.
The thus modified alloys can be used as structural elements or as a can or sheath for a fuel element in nuclear reactors.
According to said process, to the zirconium or zirconium alloy is added at least one metallic element able to stabilize the tetragonal phase of zirconia, e.g. 2 to 10% by weight of cerium.
The thus modified alloys can be used as structural elements or as a can or sheath for a fuel element in nuclear reactors.
Description
-21~8~68 W RROSTON RESISTA~I ZIRco~lu.l ALLOYS
~SA~L~ D~ ~AIBR REACTORS
The pre~eut inventlon relate4 to alloYs bas~d o~ zircon{um ~a~ing a~
~mproYe~ resistant to eorroslo~ ~n ~ace~ and ~Dre particularly usable iu boiling ~ate~ and pressurlzed ~ater nnc7ear re~ctor~.
In r~actors of t~s tYpe. known as th~rm~l reactors. ch~ 1 is caol~d natural or hea~y w~ter, which circulates la the Core at a relatively olgh te~peratur~ of e.g. 250 to 3~0C. The ~el 1~ separated fro~ ~atd ~oolln~
wate~ by a ~heath, can or cl~ generally m~de from a zirconiu2 ba~ed alloy.
Th~s, ~rco~lum h~s ~he s~ecial feature of ail~wing the passage oE ~eutrons (s~all ncntro~ ~apture section~ d~d of navi~S a relaeively ~ood resistance to corrosisn under -~ater at the ~eratl ng cemperature of the reactors.
Ihe alloys used at pr~s~nt i~ such r~actors are Zircaloys, ~hich have additio~ of t~n, chro~i~m, iron aud uickel, a~d zir~oniu~-niobium al70Ys.
These alloy~ have a~equate corro5io~ rcslstance ~haracteristics ~or the present burn-~ps of approxi~ately 35 to 45,000 ~ dt ho~ever, ~or f~ture ob~ectives vhlch are directed at alLowing t~e fuel to s~end a lor.ger ~iue In tho core aQd reach bur~-ups e~ceedlng 65 tc 75,0 MW dt , the~r ccrrosion re6istance ~ay prove to be ~nadequate.
It is 4~ow~ that the resistanc~ Co oorrosion o~ zirconluc al~oy sheaths is lin~ed ~Lth tho ~oræatio~ of a thin zircon~a ~are~
which, gener~lly, ~us~ not ~xc~ed 0.10 mm for sheath tblck~esses of 0.6 to a.s Thus, beyona said th~C'~ets~ the -a~b~nical ~trength 109s linked ~ith ~he deve70pment of said zirconia layer i5 ~x~e~Sive. ~oreove~, it is necesssry to conslder the ~xfoliatio~ p~e~omenon, ~.e. the separation ~f the very thick ~irconia layer, ~hich leads to che circulat.on of zirconia particle~
in the pri~ary ~ater of the ~ucLea~ reacto~
Research has aL~O ~ee~ u~d~rtaken ~o~ rovl~g the ~esictant tO corrosiou of ~uch zirconiu~ alloYs~ either by a~propri2Le heat treao~encs, or by a - 2 - 21S84~8 modif~catt nn of ~he cOn~pos~tion o~ the alloy~, as descrlbed ~ J. Tho~e~
et al Lrl Procee~;ne~ o~ a 'lecl~nica~ ittee rleltti~g. L9.EA, ~ortland, oreg~, IJS~, S~ptember 11-lj 19~9, pp 255-262 ~Tul 5. Isobe et al, 9th Inter. Conf. 2r in llucl. Iud., Rob~, Z~apanl AST~l-STP 1132~ p 346.
;~irconlum-n:;obi~n allcys llLodified ln order to in~prove t~eir ;orroslon res- sta~ce ~re de~cribed i~ DE-B-l 202 985 (Sie~ens} . In this document, to the alloy is added a verg s~all a~ou~t of ceriu~ ~0.05 to 1~> pre~erably 0.01 to 0~5X), which ~a'~e~ it possible to r~duce ~he thick~e~s of th~
10 zirco~ ~m oxide layer for~ed on the shllath. ~owe~er. the ~esults giv~n 1D.
the abo~e p2ter~ c~ly reveal a ~1 n~ rovement to the corrosion resis-tance of t~e Zr-~b a;l~ys.
Thu~ to lloli, it ha6 n~t been posslble to c~btair~ an ade~luAte lm~L~ V~ -n~15 to t~e corroslo~ re~istance of zircon~ a'loys.
The preseD.t inventio~ ls ai~d at a process 'or ~pro~r~ng th~ corrosion re~tance in water of zi~conLu~ a~d zireonium alloys and whic~ ~akes it poæsible to achidYe e~is obJ ec .ive .
This proce~ ~on~ist.~ o~ addlng to the 2irconiur or zirconium alloy at least one metallic eLe~ent able to stabllize Ihe tetra~onal pha~- of zir-conia.
2; ~hus, accordln~ to the ~nvention, the proble~s of corros~on ln ~ater of zirco~i~ a~d $t~ alloy~ are solved by stabilLzin~ t~e ~irconia layer deY~lopin~ on the surf~ce o~ the aLloY i~ tetragonal form.
~hus, it ba~ bee~ found that d~ring t~e oxidatio~ of a zirco~i~m allo~- in ~ats~ at hi~h te~perature, ~here ~a~ a ~Uccession ~f t~70 sta~es. I~ a ~irst sta~e, che 2irconium cxide wh~c~ form~ by reacti~$ ~ith water, 1 ~rotect-ve ~d the grow~ of the zirco~iu~ oxide layer continues in ~h~
tetrago~ai phase wLth a parabolLc speed pro~lle. In the seco~d stage, the tetrago~a7 oxlde layer i~ transfor~ed in~o a cuble or ~onoclinic oxide i~r, ~hich br-ngs 2~0ut a fi~e crack~n~ of the zireonia, so that lt le6es its protecti~e c~aracter and in~ces a corroslon k~netics transition.
-2I 58~ ~8 ~cording to t4e invention7 the z~rcon~a laye~ is stabilized t~ avoid or de~ay this trflns~onm~10n ~nd ~ai~ta$~ the corroslon ki~etics at a lo~
Level.
The ~etallic eLe~ent5 able to srabilize ~he tetra~o~a7 phase of t~e zirc-onia ca~ e.g. ~e cerim~ or ~ne~i~m- Thu5- the~ n~t~ c eleLen~s ha~e a satio~actorY tetr~go~al phase ~t~biiizatio~ action and do nor gtve rise ~o undesirabLe f acts o~ other nat~r~s ~h~ t~ey are used in a nuclcar re2Ctor.
~0 Thus, after neutron activation t~e5e eLe~ents do nvt beco~e high e~ergy, beta emitte~s liable ta contrib~te to th~ corroslon of the zircouiu~ alloy by i~crea~l~g t~e ratiolysis o~ the ~at~r by be~a r~di~tion. ~r~over7 ~hey arc soluble ia ~rco~ u~ a~d they have a lo~ ~herma~ neutron capture L5 seccion.
Pre.erably, use is made of cer~m becaue it is so~ubl~ in zirconiuu up to a ~ontent of 6 atonic X at 850-C. ~orw ~Qr, it re~ain~7 a valency i4 when inser~ed in the lattice of the tetrago~al zirconia, which avoids the form-23 atio~ of ~xy~u~ 8a~S. vh05e presence lead~7 zo an increase in t~ di~fusiourate and therefore the cor~o6i4n rate. beca~e the oxygen ~ust trave~se said ph~se i~ o~der to sup~ly the zir~nia layer. Fi~al1y, the therra7 neutron captnre 9~c~ion of eerlu~ s~al~ (0.7 bar~ a~ 0.025 eVl~
25 Wh~n ceri~ s us~d. it is preferably added i~ a qua~tity such th~t it repre~en~s 2 to lOS 4y ~eight o~ the final alloy. ~hen ragn~ium is used.
quantit~es re~rese~t~g 2 to 10~ by we~ght of t~e fi~aL all~y are ~n~e a~ai~ ~ppropriate.
30 'r4~, it is used lp, a Gluoh highQr Qua ti~ than th2t provided b~ DS-B-l 202 985. With suoh a ~eri~m content, the tetragonal phase i~ w~ll s~ab-ilize~ by the ch~icàl efect.
The pro~:c~ aocordi~g to the i~-ent7,~n is ap~licabl- to ~111 z1 ~wniu~ based alloy-~ and ~or~ p~rticu1arly to those ~ls~d in waler nll~7e~r reactor~ such ~s ~ircaloy type allog~.
21~68 The i~ve~tion al~o relate~ t~ zirconl7~ alloys i~corporariILg a ceri,u~ a~d-itio~.
di.ng to a firs ~tbo~l~ ~ t of the inve~tio~L, the z~rCoT~t u~ alloy coi~prtses 2 to 10 ~.1 Ce ~d ~0 to 2000 pp~ oxygell, t~e residue beLng con~ticuted by zi~co~i~ and accid~ntal i~uri~les.
According to a ~eco~Ld e~bodimen~, ~he ~:irco~1~ alloy ~o~p~ises $ to 10 w~.l Ce, 500 to 2000 ~p~ o~gen a~d 0.0l to 1.5 ~ of at leaet one la ele:nc~t chosen ~ro~ amo~ Sn, ~b, Fe, C~, Ni, ~o, ~a, Ca, ~g, V, Al, ~i and Ti, pro~l~ed that the ~o~l of said elemeuts ~s at che mo~t 15 ~.~, ~he residlle being coustituted by zlrconiu~ a&d acc~ent~ Dpu~ities.
According ta a r~rd embo~e~t a~ the lnventlon, the zircu~llu~ alloy ~s a~ alloy of the Z~rcaloy t-fpe co~p~iYi~g 2 to 10 wt.~ cPrium, ~pproximately 1.5 wt.~ tin and 0.3 ~ 11 o~ iroll a~d c~rom~um.. the residue b~5.ng c:on~tltu~ed by ~lrc,~r,i-~ and accidental iaipur~t~ec.
~Le alloys dsscr~bed herei~before can b~ produecd b~ c~uv~ntional processes, e.~. bY vac~u~ ~el~ a ~urnace havlng a ccnsumable electrode, because ~he vapour pre~ure o~ ce~ium i~ the Liquid p~nse is equivalent ~o that of tin, ~hich does not lead to ~y partic~lar proble26 o~ mel~ing. Following series of vacuu~ ~elti~g3, the alloy can be f~rged, ~3t rolled ~nd the~
coLd ro~ed. ~he hcat treat2ents in the ~nA~ prod~ction pha~c can be 25 ~od~fi~d to ta~e ad~a~tage of the sol~bil~ ty of ceriu~ at ~igh te~erature in the alp4a phase of 7-irconiu~. ~hus. it ~s posslble to carry out 2 homcge~ization hest treat~ent by di~olving at ~50 to 863-C, e.g. 850-C, prior to carr~ing o~t te~peri~g and ~ possible an~eallng treat~t i~ ord~
to obtain a very ~i~e ceriu~ precipitatlo~.
T~e zirconlu~ alloys descr~bed herei~before can be used as structural ele~ents i~ water-cooled nuclç~r reactors an~ i~ par~ic~lar in nuclear fuel asse~bl~es and rods, i.e. in g~de tubes, ~ratin~s and rod c~ns.
I~ the c~e o f cans, thev can also be u6ed in ~he outer part o~ the two- layer ~ans (dupl.e~ can~), which are lnterna~y coated ~ith high purlty 215846~
z1rconlum or a3y other ~etal re~l-clng the b~ea~i~8 ~h~nr~ by lnterac~lon between the pellets a~d t4e can.
~t ls al~o po~ible to use these alloyq in c~si~g~ of boiling ~ater reac-5 tors, i.~. in cyliDdrical ele~ents ha~ng ~ ~suare cross-seceion surraund-ing the ~el assem~lles. so as co avoid hydraul~ ta~ lltie6 lln~ed vlth Local ~ol~;ng.
En the ~a~e ~ay. in heavr water re~cto~, the force tubes preseatly ~ad~
ro~ 21;coQiua-niobi~m aLloy ~d which are e~pos~d to o~idation prob~ms oould be made ~lth ~he alloy~ a~cording to the i~vent~on.
Other features and adva~a~e~ of the in~e~tion c~n b~ ga~h~r~d fro~ th~
~oLlo~ g ~p~cifie des~rlptlon wlth ~efipece to t~e ~ollo~ing drawings, li wherein show:
~lg. 1 ~iagra~3tic~1lY the evolutlon of t~e zirconla layer for~in~
on a zirconium sheath b~ oxida~io~ tn ~ater.
Fig. 2 A gr~p~ ~ho~ing e~e thic~ness variations of the zirconia Layer a~ a f~ctlon o~ ti~e, during an oxidhtion i~ water.
ho~s that d~ring oxida~ion ~ water of a z~rconiu~ 3heath, r~A~ing or can 1~ o~ the surface of the sheath 19 for~e~ a ~etragonal zirconiu~
o~lde layer 3 a~d Lt8 thic~es~ i~cre~es in the course of tLme.
In flg. 2 (curve 1), ~hich ~pres~t~ t~ va~iations ~ n thickne5s of said layer a~ a f~nction of ttme. ~ t can be see~ t~at the thicknes~ l~itially increa~es slo~ b (first sta~e~ with a ~arabolic speed profile and reaches the point ~1~ a~ fro~ ~hich the zirconia phA~e ~rsnsition occurs.
At thi.s ~ta~e, whic~ co~r~sponds to the second stage of the co~rosion pro-ce~ and a6 can be ~eeG ~ fl~. 1, thu R~t~rnal pa~ of the tetragor.al zi~-Cona layer 3 i6 dest~h~ e~ and trar.~for~ed ~to cubic or ~onocl~c 3~ z~r_on a 5.
21~4~8 -Thts tr~nsfor~tion is asYocisted -~ith a fi~e cracki~ of the tlrconla~
which therefo~e Loses its protectlve charaeter, leading to an i~;reased cor~o~iou ~inetlcs.
S Th~s, as can be se~n in ~ig. 2, after ~oint 11, ~se ~bic~eQ~ of t~e zir-conia layer increases ~inea~l~ w~th time. In fig. 2, curve Ir lllustra~es the resnlts obtai~ed ~he~ aceordins ~o the i~vent~on, to the ~irconium or Yi~coui~ alloy i~ addqd a ~etallic ele~ent suc~ as Ce ablc to stabilize ~he tetra~onal phase of the zircon-a.
thl8 case, ~he o~idation Froeess onee ag~in ca~prlses two s~a~es, but the duration of the first stage ~p ~o T~, which corresponds to the ~eve~-~p~ent of the tetrag~al zirconia layer, ls muc~ longer. Ma~eover, m the second stage, the corrosion rate fo11Owlns ~he transit~o~ T~ i~ lo~e~
1~ (the angle O~beln~ s~aller than the angLe ~ ).
rhus, the process according to the 1n~e~tton ~a~e~ it ~os~i~le to signi-ficantly im4ro~ the corr~sion resista~oe of zirconiun and zirco~lu~
alloys.
~0 In e~empllf~e~ ~anner, the ~ollo~n~ tab~e gives several all~y composltions ~ ) accordi~g to the invention, said aLloys ~Lso eontai~ing 1000 ~o 1500 pp~ axygeT~.
2~ ~ABT E
EX Ce Fe Cr Zr 1 3 - - residue 2 ~ - - re~ldue 3 9 - - res~due 3 0.2 0.1 res~due 6 0.2 0.1 re~idue 6 9 0.2 0.1 residue 3S Thasa allay~ ar~ prepared by ~acauo electrode melting and theY hæve a be~ter c~rrosion ~esis~ance tha~ ~he kno~n alloys.
~SA~L~ D~ ~AIBR REACTORS
The pre~eut inventlon relate4 to alloYs bas~d o~ zircon{um ~a~ing a~
~mproYe~ resistant to eorroslo~ ~n ~ace~ and ~Dre particularly usable iu boiling ~ate~ and pressurlzed ~ater nnc7ear re~ctor~.
In r~actors of t~s tYpe. known as th~rm~l reactors. ch~ 1 is caol~d natural or hea~y w~ter, which circulates la the Core at a relatively olgh te~peratur~ of e.g. 250 to 3~0C. The ~el 1~ separated fro~ ~atd ~oolln~
wate~ by a ~heath, can or cl~ generally m~de from a zirconiu2 ba~ed alloy.
Th~s, ~rco~lum h~s ~he s~ecial feature of ail~wing the passage oE ~eutrons (s~all ncntro~ ~apture section~ d~d of navi~S a relaeively ~ood resistance to corrosisn under -~ater at the ~eratl ng cemperature of the reactors.
Ihe alloys used at pr~s~nt i~ such r~actors are Zircaloys, ~hich have additio~ of t~n, chro~i~m, iron aud uickel, a~d zir~oniu~-niobium al70Ys.
These alloy~ have a~equate corro5io~ rcslstance ~haracteristics ~or the present burn-~ps of approxi~ately 35 to 45,000 ~ dt ho~ever, ~or f~ture ob~ectives vhlch are directed at alLowing t~e fuel to s~end a lor.ger ~iue In tho core aQd reach bur~-ups e~ceedlng 65 tc 75,0 MW dt , the~r ccrrosion re6istance ~ay prove to be ~nadequate.
It is 4~ow~ that the resistanc~ Co oorrosion o~ zirconluc al~oy sheaths is lin~ed ~Lth tho ~oræatio~ of a thin zircon~a ~are~
which, gener~lly, ~us~ not ~xc~ed 0.10 mm for sheath tblck~esses of 0.6 to a.s Thus, beyona said th~C'~ets~ the -a~b~nical ~trength 109s linked ~ith ~he deve70pment of said zirconia layer i5 ~x~e~Sive. ~oreove~, it is necesssry to conslder the ~xfoliatio~ p~e~omenon, ~.e. the separation ~f the very thick ~irconia layer, ~hich leads to che circulat.on of zirconia particle~
in the pri~ary ~ater of the ~ucLea~ reacto~
Research has aL~O ~ee~ u~d~rtaken ~o~ rovl~g the ~esictant tO corrosiou of ~uch zirconiu~ alloYs~ either by a~propri2Le heat treao~encs, or by a - 2 - 21S84~8 modif~catt nn of ~he cOn~pos~tion o~ the alloy~, as descrlbed ~ J. Tho~e~
et al Lrl Procee~;ne~ o~ a 'lecl~nica~ ittee rleltti~g. L9.EA, ~ortland, oreg~, IJS~, S~ptember 11-lj 19~9, pp 255-262 ~Tul 5. Isobe et al, 9th Inter. Conf. 2r in llucl. Iud., Rob~, Z~apanl AST~l-STP 1132~ p 346.
;~irconlum-n:;obi~n allcys llLodified ln order to in~prove t~eir ;orroslon res- sta~ce ~re de~cribed i~ DE-B-l 202 985 (Sie~ens} . In this document, to the alloy is added a verg s~all a~ou~t of ceriu~ ~0.05 to 1~> pre~erably 0.01 to 0~5X), which ~a'~e~ it possible to r~duce ~he thick~e~s of th~
10 zirco~ ~m oxide layer for~ed on the shllath. ~owe~er. the ~esults giv~n 1D.
the abo~e p2ter~ c~ly reveal a ~1 n~ rovement to the corrosion resis-tance of t~e Zr-~b a;l~ys.
Thu~ to lloli, it ha6 n~t been posslble to c~btair~ an ade~luAte lm~L~ V~ -n~15 to t~e corroslo~ re~istance of zircon~ a'loys.
The preseD.t inventio~ ls ai~d at a process 'or ~pro~r~ng th~ corrosion re~tance in water of zi~conLu~ a~d zireonium alloys and whic~ ~akes it poæsible to achidYe e~is obJ ec .ive .
This proce~ ~on~ist.~ o~ addlng to the 2irconiur or zirconium alloy at least one metallic eLe~ent able to stabllize Ihe tetra~onal pha~- of zir-conia.
2; ~hus, accordln~ to the ~nvention, the proble~s of corros~on ln ~ater of zirco~i~ a~d $t~ alloy~ are solved by stabilLzin~ t~e ~irconia layer deY~lopin~ on the surf~ce o~ the aLloY i~ tetragonal form.
~hus, it ba~ bee~ found that d~ring t~e oxidatio~ of a zirco~i~m allo~- in ~ats~ at hi~h te~perature, ~here ~a~ a ~Uccession ~f t~70 sta~es. I~ a ~irst sta~e, che 2irconium cxide wh~c~ form~ by reacti~$ ~ith water, 1 ~rotect-ve ~d the grow~ of the zirco~iu~ oxide layer continues in ~h~
tetrago~ai phase wLth a parabolLc speed pro~lle. In the seco~d stage, the tetrago~a7 oxlde layer i~ transfor~ed in~o a cuble or ~onoclinic oxide i~r, ~hich br-ngs 2~0ut a fi~e crack~n~ of the zireonia, so that lt le6es its protecti~e c~aracter and in~ces a corroslon k~netics transition.
-2I 58~ ~8 ~cording to t4e invention7 the z~rcon~a laye~ is stabilized t~ avoid or de~ay this trflns~onm~10n ~nd ~ai~ta$~ the corroslon ki~etics at a lo~
Level.
The ~etallic eLe~ent5 able to srabilize ~he tetra~o~a7 phase of t~e zirc-onia ca~ e.g. ~e cerim~ or ~ne~i~m- Thu5- the~ n~t~ c eleLen~s ha~e a satio~actorY tetr~go~al phase ~t~biiizatio~ action and do nor gtve rise ~o undesirabLe f acts o~ other nat~r~s ~h~ t~ey are used in a nuclcar re2Ctor.
~0 Thus, after neutron activation t~e5e eLe~ents do nvt beco~e high e~ergy, beta emitte~s liable ta contrib~te to th~ corroslon of the zircouiu~ alloy by i~crea~l~g t~e ratiolysis o~ the ~at~r by be~a r~di~tion. ~r~over7 ~hey arc soluble ia ~rco~ u~ a~d they have a lo~ ~herma~ neutron capture L5 seccion.
Pre.erably, use is made of cer~m becaue it is so~ubl~ in zirconiuu up to a ~ontent of 6 atonic X at 850-C. ~orw ~Qr, it re~ain~7 a valency i4 when inser~ed in the lattice of the tetrago~al zirconia, which avoids the form-23 atio~ of ~xy~u~ 8a~S. vh05e presence lead~7 zo an increase in t~ di~fusiourate and therefore the cor~o6i4n rate. beca~e the oxygen ~ust trave~se said ph~se i~ o~der to sup~ly the zir~nia layer. Fi~al1y, the therra7 neutron captnre 9~c~ion of eerlu~ s~al~ (0.7 bar~ a~ 0.025 eVl~
25 Wh~n ceri~ s us~d. it is preferably added i~ a qua~tity such th~t it repre~en~s 2 to lOS 4y ~eight o~ the final alloy. ~hen ragn~ium is used.
quantit~es re~rese~t~g 2 to 10~ by we~ght of t~e fi~aL all~y are ~n~e a~ai~ ~ppropriate.
30 'r4~, it is used lp, a Gluoh highQr Qua ti~ than th2t provided b~ DS-B-l 202 985. With suoh a ~eri~m content, the tetragonal phase i~ w~ll s~ab-ilize~ by the ch~icàl efect.
The pro~:c~ aocordi~g to the i~-ent7,~n is ap~licabl- to ~111 z1 ~wniu~ based alloy-~ and ~or~ p~rticu1arly to those ~ls~d in waler nll~7e~r reactor~ such ~s ~ircaloy type allog~.
21~68 The i~ve~tion al~o relate~ t~ zirconl7~ alloys i~corporariILg a ceri,u~ a~d-itio~.
di.ng to a firs ~tbo~l~ ~ t of the inve~tio~L, the z~rCoT~t u~ alloy coi~prtses 2 to 10 ~.1 Ce ~d ~0 to 2000 pp~ oxygell, t~e residue beLng con~ticuted by zi~co~i~ and accid~ntal i~uri~les.
According to a ~eco~Ld e~bodimen~, ~he ~:irco~1~ alloy ~o~p~ises $ to 10 w~.l Ce, 500 to 2000 ~p~ o~gen a~d 0.0l to 1.5 ~ of at leaet one la ele:nc~t chosen ~ro~ amo~ Sn, ~b, Fe, C~, Ni, ~o, ~a, Ca, ~g, V, Al, ~i and Ti, pro~l~ed that the ~o~l of said elemeuts ~s at che mo~t 15 ~.~, ~he residlle being coustituted by zlrconiu~ a&d acc~ent~ Dpu~ities.
According ta a r~rd embo~e~t a~ the lnventlon, the zircu~llu~ alloy ~s a~ alloy of the Z~rcaloy t-fpe co~p~iYi~g 2 to 10 wt.~ cPrium, ~pproximately 1.5 wt.~ tin and 0.3 ~ 11 o~ iroll a~d c~rom~um.. the residue b~5.ng c:on~tltu~ed by ~lrc,~r,i-~ and accidental iaipur~t~ec.
~Le alloys dsscr~bed herei~before can b~ produecd b~ c~uv~ntional processes, e.~. bY vac~u~ ~el~ a ~urnace havlng a ccnsumable electrode, because ~he vapour pre~ure o~ ce~ium i~ the Liquid p~nse is equivalent ~o that of tin, ~hich does not lead to ~y partic~lar proble26 o~ mel~ing. Following series of vacuu~ ~elti~g3, the alloy can be f~rged, ~3t rolled ~nd the~
coLd ro~ed. ~he hcat treat2ents in the ~nA~ prod~ction pha~c can be 25 ~od~fi~d to ta~e ad~a~tage of the sol~bil~ ty of ceriu~ at ~igh te~erature in the alp4a phase of 7-irconiu~. ~hus. it ~s posslble to carry out 2 homcge~ization hest treat~ent by di~olving at ~50 to 863-C, e.g. 850-C, prior to carr~ing o~t te~peri~g and ~ possible an~eallng treat~t i~ ord~
to obtain a very ~i~e ceriu~ precipitatlo~.
T~e zirconlu~ alloys descr~bed herei~before can be used as structural ele~ents i~ water-cooled nuclç~r reactors an~ i~ par~ic~lar in nuclear fuel asse~bl~es and rods, i.e. in g~de tubes, ~ratin~s and rod c~ns.
I~ the c~e o f cans, thev can also be u6ed in ~he outer part o~ the two- layer ~ans (dupl.e~ can~), which are lnterna~y coated ~ith high purlty 215846~
z1rconlum or a3y other ~etal re~l-clng the b~ea~i~8 ~h~nr~ by lnterac~lon between the pellets a~d t4e can.
~t ls al~o po~ible to use these alloyq in c~si~g~ of boiling ~ater reac-5 tors, i.~. in cyliDdrical ele~ents ha~ng ~ ~suare cross-seceion surraund-ing the ~el assem~lles. so as co avoid hydraul~ ta~ lltie6 lln~ed vlth Local ~ol~;ng.
En the ~a~e ~ay. in heavr water re~cto~, the force tubes preseatly ~ad~
ro~ 21;coQiua-niobi~m aLloy ~d which are e~pos~d to o~idation prob~ms oould be made ~lth ~he alloy~ a~cording to the i~vent~on.
Other features and adva~a~e~ of the in~e~tion c~n b~ ga~h~r~d fro~ th~
~oLlo~ g ~p~cifie des~rlptlon wlth ~efipece to t~e ~ollo~ing drawings, li wherein show:
~lg. 1 ~iagra~3tic~1lY the evolutlon of t~e zirconla layer for~in~
on a zirconium sheath b~ oxida~io~ tn ~ater.
Fig. 2 A gr~p~ ~ho~ing e~e thic~ness variations of the zirconia Layer a~ a f~ctlon o~ ti~e, during an oxidhtion i~ water.
ho~s that d~ring oxida~ion ~ water of a z~rconiu~ 3heath, r~A~ing or can 1~ o~ the surface of the sheath 19 for~e~ a ~etragonal zirconiu~
o~lde layer 3 a~d Lt8 thic~es~ i~cre~es in the course of tLme.
In flg. 2 (curve 1), ~hich ~pres~t~ t~ va~iations ~ n thickne5s of said layer a~ a f~nction of ttme. ~ t can be see~ t~at the thicknes~ l~itially increa~es slo~ b (first sta~e~ with a ~arabolic speed profile and reaches the point ~1~ a~ fro~ ~hich the zirconia phA~e ~rsnsition occurs.
At thi.s ~ta~e, whic~ co~r~sponds to the second stage of the co~rosion pro-ce~ and a6 can be ~eeG ~ fl~. 1, thu R~t~rnal pa~ of the tetragor.al zi~-Cona layer 3 i6 dest~h~ e~ and trar.~for~ed ~to cubic or ~onocl~c 3~ z~r_on a 5.
21~4~8 -Thts tr~nsfor~tion is asYocisted -~ith a fi~e cracki~ of the tlrconla~
which therefo~e Loses its protectlve charaeter, leading to an i~;reased cor~o~iou ~inetlcs.
S Th~s, as can be se~n in ~ig. 2, after ~oint 11, ~se ~bic~eQ~ of t~e zir-conia layer increases ~inea~l~ w~th time. In fig. 2, curve Ir lllustra~es the resnlts obtai~ed ~he~ aceordins ~o the i~vent~on, to the ~irconium or Yi~coui~ alloy i~ addqd a ~etallic ele~ent suc~ as Ce ablc to stabilize ~he tetra~onal phase of the zircon-a.
thl8 case, ~he o~idation Froeess onee ag~in ca~prlses two s~a~es, but the duration of the first stage ~p ~o T~, which corresponds to the ~eve~-~p~ent of the tetrag~al zirconia layer, ls muc~ longer. Ma~eover, m the second stage, the corrosion rate fo11Owlns ~he transit~o~ T~ i~ lo~e~
1~ (the angle O~beln~ s~aller than the angLe ~ ).
rhus, the process according to the 1n~e~tton ~a~e~ it ~os~i~le to signi-ficantly im4ro~ the corr~sion resista~oe of zirconiun and zirco~lu~
alloys.
~0 In e~empllf~e~ ~anner, the ~ollo~n~ tab~e gives several all~y composltions ~ ) accordi~g to the invention, said aLloys ~Lso eontai~ing 1000 ~o 1500 pp~ axygeT~.
2~ ~ABT E
EX Ce Fe Cr Zr 1 3 - - residue 2 ~ - - re~ldue 3 9 - - res~due 3 0.2 0.1 res~due 6 0.2 0.1 re~idue 6 9 0.2 0.1 residue 3S Thasa allay~ ar~ prepared by ~acauo electrode melting and theY hæve a be~ter c~rrosion ~esis~ance tha~ ~he kno~n alloys.
Claims (9)
1. Process for improving the corrosion resistance in water of zirconium and zirconium alloys, characterized in that it consists of adding to the zirconium or zirconium alloy at least one metallic element able to stabilize the tetragonal phase of the zirconia, said element being added in an adequate quantity to stabilize in tetragonal form the zirconia layer developing on the surface of the zirconium orzirconium alloy on contact with water.
2. Process according to claim 1, characterized in that said element is Ce or Mg.
3. Process according to claim 1, characterized in that said element is Ce and that it is added in a quantity such that it represents 2 to 10 wt.% of the final alloy.
4. Zirconium alloy, characterized in that it comprises 2 to 10 wt.% Ce and 500to 2000 ppm oxygen, the residue being constituted by zirconium and accidental impurities.
5. Zirconium alloy, characterized in that it comprises 2 to 10 wt.% Ce, 500 to2000 ppm oxygen and 0.1 to 1.5 wt.% of at least one element chosen from among Sn, Nb, Fe, Cr, Ni, Mo, Ta, Ca, Mg, V, Al, Si and Ti, provided that the total of said elements is at the most 15 wt.%, the residue being constituted by zirconium and accidental impurities.
6. Alloy according to claim 4, characterized in that it comprises 3 to 9 wt.%
cerium.
cerium.
7. Alloy according to claim 5, characterized in that it comprises 3 to 9 wt.%
cerium, 1000 to 1500 ppm oxygen, 0.2 wt.% iron and 0.1 wt.% chromium, the residue being constituted by zirconium and accidental impurities.
cerium, 1000 to 1500 ppm oxygen, 0.2 wt.% iron and 0.1 wt.% chromium, the residue being constituted by zirconium and accidental impurities.
8. Zirconium alloy, characterized in that it comprises 2 to 10 wt.% cerium, approximately 1.5 wt.% tin and 0.3 wt.% in all of iron and chromium, the residuebeing constituted by zirconium and accidental impurities.
9. Use of an alloy according to any one of the claims 4 to 7 as a structural material or as a fuel element can in a water-cooled nuclear reactor.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9303199A FR2702776B1 (en) | 1993-03-19 | 1993-03-19 | Corrosion-resistant zirconium alloys, usable in particular in water reactors. |
| FR93/03199 | 1993-03-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2158468A1 true CA2158468A1 (en) | 1994-09-29 |
Family
ID=9445162
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002158468A Abandoned CA2158468A1 (en) | 1993-03-19 | 1994-03-18 | Corrosion resistant zirconium alloys usable in water reactors |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0689616B1 (en) |
| JP (1) | JPH08508067A (en) |
| KR (1) | KR960701231A (en) |
| CA (1) | CA2158468A1 (en) |
| DE (1) | DE69401126T2 (en) |
| ES (1) | ES2097644T3 (en) |
| FR (1) | FR2702776B1 (en) |
| WO (1) | WO1994021834A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100415265B1 (en) * | 2001-03-26 | 2004-01-16 | 한국전력공사 | An inhibition method of the secondary side stress corrosion cracking in nuclear steam generator tubes |
| AT411535B (en) * | 2002-02-05 | 2004-02-25 | Vacumet Ag | ALLOY FOR COMPONENTS WITH AMORPHOUS STRUCTURE AND METHOD FOR PRODUCING THE ALLOY |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1241998B (en) * | 1961-12-27 | 1967-06-08 | Siemens Ag | Zirconium alloy |
| US3163744A (en) * | 1962-02-23 | 1964-12-29 | United Aircraft Corp | Non-consumable arc-melting and arc-welding electrodes |
| DE1202986B (en) * | 1962-09-29 | 1965-10-14 | Siemens Ag | Zirconium alloy |
| DE1202985B (en) * | 1962-09-29 | 1965-10-14 | Siemens Ag | Zirconium alloy |
| US3378671A (en) * | 1965-10-14 | 1968-04-16 | United Aircraft Corp | Nonconsumable arc-melting and arc-welding electrodes |
| JP2559136B2 (en) * | 1988-10-26 | 1996-12-04 | 三菱マテリアル株式会社 | Zr alloy for reactor fuel cladding support grid |
-
1993
- 1993-03-19 FR FR9303199A patent/FR2702776B1/en not_active Expired - Fee Related
-
1994
- 1994-03-18 ES ES94910437T patent/ES2097644T3/en not_active Expired - Lifetime
- 1994-03-18 DE DE69401126T patent/DE69401126T2/en not_active Expired - Fee Related
- 1994-03-18 WO PCT/FR1994/000299 patent/WO1994021834A1/en active IP Right Grant
- 1994-03-18 CA CA002158468A patent/CA2158468A1/en not_active Abandoned
- 1994-03-18 KR KR1019950703876A patent/KR960701231A/en not_active Application Discontinuation
- 1994-03-18 EP EP94910437A patent/EP0689616B1/en not_active Expired - Lifetime
- 1994-03-18 JP JP6520720A patent/JPH08508067A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0689616A1 (en) | 1996-01-03 |
| KR960701231A (en) | 1996-02-24 |
| WO1994021834A1 (en) | 1994-09-29 |
| FR2702776A1 (en) | 1994-09-23 |
| ES2097644T3 (en) | 1997-04-01 |
| JPH08508067A (en) | 1996-08-27 |
| EP0689616B1 (en) | 1996-12-11 |
| FR2702776B1 (en) | 1995-04-28 |
| DE69401126D1 (en) | 1997-01-23 |
| DE69401126T2 (en) | 1997-06-05 |
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