SE204450C1

SE204450C1 -

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Publication number: SE204450C1
Authority: SE
Publication date: 1965-01-01

Description

Uppfinnare: J Hafuth Prioritet begard film den 7 mars 1960 (USA) Foreliggande uppfinning avser ett satt att framstalla bransleelement for en karnreaktor. Narmare bestamt avses ett sadant satt, varvid sintrad eller gjuten urandioxid males och sallas till ett flertal partikelstorleksfraktioner och valda fraktioner, dar storleksforhallandet mellan efter varandra foljande fraktioners partikelstorlek är stort, blandas och inforas i ett vertikalt metallror. Inventor: J Hafuth Priority Required Film March 7, 1960 (USA) The present invention relates to a method of producing fuel elements for a nuclear reactor. More specifically, it refers to such a process, in which sintered or cast uranium dioxide is ground and salted into a plurality of particle size fractions and selected fractions, where the size ratio between the particle sizes of successive fractions is large, mixed and introduced into a vertical metal tube.

Ett forbattrat satt aft framstalla keramiska bransleelement angives i den franska patentskriften 1 238 751. Foreliggande uppfinning kan tilllampas i kombination med eller i stallet for den i namnda patent angivna sanksmidesmetoden. An improved set of fabricated ceramic fuel elements is disclosed in French Patent Specification 1,238,751. The present invention may be practiced in combination with or in place of the sink forging method set forth in the said patent.

Forfarandet att genom vibration komprimera pulver tillampas givetvis allmant inom tekniken. Dot har redan insetts, att det är mOjligt att genom vibrationskomprimering av partikelblandningar astadkomma storre tathet, om pulverpartiklarna ha viss vald storlek, an om pulverstorleken ãr obestamd. En avhandling om komprimering genom vibration och de bAsta forfarandena harfor fore tillkomsten av foreliggande uppfinning finnes i NAA-SR-4155, som är utgiven den 1 oktober 1959 och finnes tillganlig hos Office of Technical Services, Department of Commerce, Washington 25, D.C., Amerikas Forenta Stater. Ax denna avhandling framgar det, aft den storsta Whet, som kunnat uppnas, varit 9,00 gicm3, vilket är 82,2 % av den teoretiska tatheten. Eftersom donna tathet Or lagre On den, som behoves i karnreaktorer, maste det komprimerade materialet sammanpackas annu mer, och detta sker med andra medel, sasom sanksmidning. The process of compressing powder by vibration is, of course, widely applied in the art. It has already been realized that it is possible to achieve greater density by vibrational compression of particle mixtures, if the powder particles have a certain selected size, than if the powder size is indeterminate. A dissertation on vibration compression and the best procedures for obtaining the present invention is found in NAA-SR-4155, issued October 1, 1959 and available from the Office of Technical Services, Department of Commerce, Washington 25, DC, USA. United States. According to this dissertation, the largest Whet that could be achieved was 9.00 gicm3, which is 82.2% of the theoretical density. Since donna tathet Or lagre On den, which is needed in nuclear reactors, the compressed material must be packed even more, and this is done by other means, such as sink forging.

Foreliggande uppfinning kannetecknas darav, att metallrorct med anvandning av en vibrator, som vibrerar roret i vertikal riktning vibreras vid en frek-vens, som Or lika med och foljer dem med sammanpackningen av pulvret varierande grundresonansfrekvensen hos det system, som inne, fattar roret och pulvret i det monterade laget.. Metallroret kan aven vibreras vid frekveriser ovanfor och under namnda grundresonansfrekvens, varvid vibreringsfrekvensen ovanf Or grundresonansfrekvensen eventuellt bildar en harr. monisk svangning till grundresonansfrekvensen. Om det dá anvandes en vibrator, som vibrerar roret i vertikal riktning, kan sattet enligt uppfinningen innefatta foljande steg: vibrering med liten effekt och vid en frekvens Over grundresonansfrekvensen, snabb minskning av vibreringsfrekvensen ner' till rorets grundresonansfrekvens, &fling av effekten och andring av vibreringsfrekvensen Over och omkring grundresonansfrekvensen ett flertal ganger, minskning av vibreringsfrekvensen till ett varde under riirets grundresonansfrekvens, okning av vibreringsfrekvensen till grundresonansfrekvensvd.rdet och andring av vibreringsfrekvensen till varden pa anise sidor om grundresonansfrekvensen ett flertal ganger, okning av vibreringsfrekvensen till et harmoniskt oversvangningsvarde for grundresonansfrekvensen och andring av vibreringsfrek,- vensen till varden pa omse sidor om den harmoniska frekvensen ett flertal ganger, samt Okning av vibreringsfrekvensen till ett frekvensvarde, som ligger betydligt Over grundreso, nansfrekvensen. The present invention is characterized in that the metal tube using a vibrator which vibrates the tube in the vertical direction is vibrated at a frequency equal to and follows them with the packing of the powder varying the fundamental resonant frequency of the system which contains the tube and the powder. in the mounted layer .. The metal tube can also be vibrated at frequencies above and below said basic resonant frequency, whereby the vibration frequency above Or the basic resonant frequency possibly forms a grayling. monic oscillation to the fundamental resonant frequency. If a vibrator is then used which vibrates the tube in the vertical direction, the set according to the invention may comprise the following steps: vibration with low power and at a frequency Over the fundamental resonant frequency, rapid reduction of the vibration frequency down to the basic resonant frequency of the tube, Above and around the fundamental resonant frequency several times, decreasing the vibration frequency to a value below the fundamental resonant frequency of the ring, increasing the vibrating frequency to the fundamental resonant frequency value and changing the vibrating frequency to the value on anise sides of the fundamental resonant frequency several times, increasing the fundamental frequency of vibrating frequency changing the vibration frequency, - the frequency of the value on the sides of the harmonic frequency several times, and increasing the vibration frequency to a frequency value which is significantly above the fundamental resonance frequency.

I det foljande lamnas en allman beskrivning av framstallningen enligt uppfinningen av ett brans,- leelement Mr en kdrnreaktor. Sintrade eller 2204 4 branda presskroppar eller stycken av keramiskt material males och sallas eller siktas, sa att fraktoner bestiende av partiklar, som ha onskad storlek, avskiljas sasom beskrives i det foljande. forhand bestamda mangder av de olika fraktionema vagas, och blandas grundligt. En lamplig mangd av blandningen halles sedan in i ett metallror, som har en hatta eller propp fastsvetsad pa sin undre ande. Floret fastsattes pa en stor rorlig, elektromagnetisk vibrator och vibreras med frekvenser som under tre minuter gradvis andras frail 100 till 4000 perioder per sekund. Under de fOrsta fein sekunderna okas tatheten snabbt, varefter den Okas langsammare, och efter tre minuter är den praktiskt taget fullstandig. Karnans tathet mates medelst en sá kallad )gamma-absorptometer*, och branslestaven skares till foreskriven langd. En hatta eller propp svetsas fast pa rerets andra ande, och staven ar fardig for insattning i ett bransleelement. Genom detta forfarande kunna tatheter upp till 90 % av den teoretiska uppnas med 1 % fel i serietillverkning. In the following a general description of the production according to the invention of an industrial element Mr a nuclear reactor is left. Sintered or burnt compacts or pieces of ceramic material are ground and sieved or sieved so that fractons consisting of particles of desired size are separated as described below. predetermined amounts of the various fractions are weighed, and mixed thoroughly. An appropriate amount of the mixture is then poured into a metal tube having a cap or stopper welded to its lower end. The floor was attached to a large moving, electromagnetic vibrator and vibrated at frequencies that for three minutes gradually changed from 100 to 4000 periods per second. During the first fine seconds the density increases rapidly, after which it increases more slowly, and after three minutes it is practically complete. The density of the core is measured by means of a so-called "gamma absorptometer", and the industry rod is cut to the prescribed length. A hat or stopper is welded to the other end of the tube, and the rod is ready for insertion into a fuel element. Through this procedure, densities up to 90% of the theoretical can be achieved with 1% error in series production.

I det foljande lamnas ett detaljerat exempel pa ett sarskilt lampligt satt att tillampa foreliggande uppfinning. Den branslestav som framstalles, är avsedd att anvandas i reaktor benamnd »Plutionium Recycle Test Reactor* (PRTR), som är under byggnad hos Hanford Engineer Works, Richland, Washington, Amerikas Forenta Stater. Etir denna reaktor foreskrives urandioxid med en tathet av 84,5 % av den teoretiska kristallografiska tatheten. In the following, a detailed example is provided of a particularly suitable way of applying the present invention. The industry rod produced is intended for use in a reactor called the Plutionium Recycle Test Reactor (PRTR), which is under construction at Hanford Engineer Works, Richland, Washington, United States of America. For this reactor, uranium dioxide is prescribed with a density of 84.5% of the theoretical crystallographic density.

Sintrad eller gjuten urandioxid males och sallas eller siktas till fraktioner med onskad kornstorlek. En uppvagd mangd av materialet halles i ett av Zircalloy-2 bestaende ror, p5. vilkets undre ande en hatta eller propp fastsvetsas dessforinnan. En »fOljare» bestaende av en lang, graderad, av en vikt belastad &tang ar inford i detta ror. Floret bibringas vibrerande rorelser pa en vibrator av en typ, som benamnes oGenisco-Savage V 1000 B» och drives av tva. seriekopplade 1-kilowatts fOrstarkare, varvid det anvandes en signal frau en 5 till 5000 hz svepfrekvensoscillator. Den luftkylda vibratom kan upptaga + 340 kg axialbelastning. Sintered or cast uranium dioxide is ground and salted or sieved into fractions of the desired grain size. A weighted amount of the material is kept in one of Zircalloy-2's existing pipes, p5. the lower spirit of which a hat or stopper is welded beforehand. A "follower" consisting of a long, graduated, weight-loaded & pliers is inserted into this tube. The flower is subjected to vibrating motions on a vibrator of a type called oGenisco-Savage V 1000 B »and driven by two. series-connected 1-kilowatt amplifier, using a signal from a 5 to 5000 Hz sweep frequency oscillator. The air-cooled vibrator can absorb + 340 kg axial load.

I det speciella utforandet var frekvensen till en borjan vid lag effekt 1000 hz, dvs. betydligt hogre an den tomma metallkapselns resonansfrekvens. Darefter minskades frekvensen snabbt, varvid partildarna delvis orienterades och packades samman. Vid jamforelsevis lag frekvens (ungefar 180 hz) observerades en rnycket snabb amplitud- och accelerationsokning. Samtidigt okades tatheten snabbt, vilket framgick darav, att doljaren» snabbt sjonk i roret. Nar resonansfrekvensen uppnatts, slapptes full strom pa. Frekvensen sveptes da. flera ganger langsamt fram och ater Over resonansfrekvensen (± 100 hz), vilken andrades till 240 hz, allt eftersom partiklarna sammanp ackades. In the special embodiment, the frequency of an initial at low power was 1000 Hz, i.e. significantly higher than the resonant frequency of the empty metal capsule. Thereafter, the frequency was rapidly reduced, with the batches being partially oriented and packed together. At a comparatively low frequency (approximately 180 Hz), a slightly faster amplitude and acceleration increase was observed. At the same time, the tension increased rapidly, which was evident from the fact that the dollar "quickly sank in the rudder. When the resonant frequency was reached, full current was released. The frequency was then swept. several times slowly back and forth Over the resonant frequency (± 100 Hz), which was changed to 240 Hz, as the particles were compacted.

Darefter minskades vibreringsfrekvensen till ungefar 100 hz och okades sedan anyo till resonansfrekvensen och sveptes Over denna flera ganger. Darefter Okades frekvensen Ater, tills en Overton av grundegensvangningstalet uppnatts, och sveptes fram och Ater Over overtonen, varefter den okades till ungefar 4 khz. Hela denna process varade ungefar tre minuter. Thereafter, the vibration frequency was reduced to about 100 Hz and then increased anyo to the resonant frequency and swept over this several times. Then the frequency Ater was increased, until an Overtone of the fundamental gain number was reached, and swept forward and the Ater Over harmonic, after which it was increased to about 4 khz. This whole process lasted about three minutes.

De harigenom erhallna stavarna aro fullkomligt tillfredsstallande. Inga dimensionsandringar forekommo, och kapslingen skadades varken fore eller efter bestralning, vilket resultat kan tillskrivas vibrationen. The rods thus obtained are perfectly satisfactory. No dimensional changes occurred, and the enclosure was damaged neither before nor after irradiation, which result can be attributed to the vibration.

Det anvanda forfarandet innefattade »avstamning» av vibratorn, varf Or frekvensandringshastigheterna icke voro exakt lika. Den tid, som star till forfogande for att genomfora hela processen ger de ungefarliga andringshastigheter, sorn b6ra anvandas. The method used involved "tuning" the vibrator, where the frequency change rates were not exactly the same. The time available to carry out the whole process gives them harmless rates of change, which should be used.

Det automatiska frekvensandringsforfarandet undersoktes medelst en pa oscillatorn anordnad mekanism for att *svepa» Over ett flertal olika frekvensomraden. Resultat astadkomna genom automatisk och manuell frekvensandring j amfordes genom observation av komprimeringshastigheten, som angives av en ovanpa branslepelaren vilande foljarstang. Det visade sig, att varierande frekvensandringshastigheter ge Onskade hoga tatheter pa kortare tid an en viss bestamd andringshastighet. Med nuvarande utrustning ger manuell avstamning narmare Overensstammelse mellan komprimeringshastigheten och vibrationsfrekvensen samt frekvensandringshastigheten an vad som blir fallet vid automatisk genomgang av frekvenscykeln vid viss bestamd andringshastighet. Foreliggande uppfinfling omfattar bade automatisk och manuell frekvensavstamning. The automatic frequency change procedure was examined by means of a mechanism arranged on the oscillator to "sweep" over a number of different frequency ranges. Results obtained by automatic and manual frequency change are compared by observing the compression rate indicated by a follower bar resting on top of the fuel column. It turned out that varying frequency change rates give desired high densities in a shorter time than a certain fixed change rate. With current equipment, manual tuning provides a closer match between the compression speed and the vibration frequency as well as the frequency change speed than what is the case with automatic review of the frequency cycle at a certain determined change speed. The present invention includes both automatic and manual frequency tuning.

Det beskrivna forfarandet tillampades pa grand av att det befiumits, att alla typer av bransleelement, och i mindre man alla bransleelement av viss typ, arc olika, vilket medf Or en speciell anpassning av vibrationssystemets mekaniska egenskaper, samt branslematerialets partikelstorlek och storleksfordelning men mycket obetydlig andring av forfarandet. Andringar av belastning, branslematerial, branslerorets koppling till vibratorn etc. andra obetydligt de frekvenser som ge basta effekten vid komprimering av branslematerialet. Det beskrivna forfarandet ger maximal kompression oberoende av dessa sma variationer. The described method was applied on the grounds that it was found that all types of fuel elements, and to a lesser extent all fuel elements of a certain type, were different, which entailed a special adaptation of the mechanical properties of the vibration system, as well as the fuel particle size and size distribution. of the procedure. Changes in load, fuel material, fuel pipe connection to the vibrator, etc. are insignificant to the frequencies that give the best effect when compressing the fuel material. The described method provides maximum compression regardless of these small variations.

Det liar visserligen befunnits vara onskvart aft anvanda den viktbelastade foljaren, men detta utgor icke nagonting for uppfinningen vasentligt. Although it has been found to be inconvenient to use the weight-loaded follower, this does not constitute anything essential to the invention.

Eoljande tabell innehaller resultaten av ett natal provningar under tillampning av det i det foregaende angivna forfarandet. 20443 Tabell I. The oil table contains the results of a natal test using the procedure given above. 20443 Table I.

Tatheten i komprimerad U0 Typ Partikelstorlek Vikt %Tyler siktnr. Vikt avZr-2-ror UO2 (kg) 15ngd. ytter- diam.tjoelc_lek Min Tathet i % av teoretisk Syntron MAW elekt- paekareromagn. vibrator Sintrad och malen (1) 100—20 + 100 (4) 3,3 2134; 19,05 x 0,89 58-62 69 Sintrad och malen 60—3+ 8 3,0 2438; 14,48 x 0,76 — 8 —20 +100 —200 Sintrad och malen 60—34- 8 3,2438; 14,48 x 0,76 — 84 —20 +100 Sintrad och malen 60— 63,2 2438; 14,48 x 0,76 — 87 18—35 +6 22—200 Brand, malen (2) 60— 6+ 1,8 2438; 14,48 x 0,76 82 90 —35 +6 —100+200 Brand, malen 60— 14 + 1,0 914; 19,05 x 0,89 — 83,1 —65 +100 —200+3 Elektrolytisk (3) I framstalld form 1,6 914; 19,05 x 0,89 53 6 Partikeltathet 95 % av den teoretiska 99%e 93%* Partike1storhetsomr5de for sankessmidda bransleelement PRT-reaktorer. Density in compressed U0 Type Particle size Weight% Tyler sieve no. Weight of Zr-2-ror UO2 (kg) 15ngd. outer diam.tjoelc_lek Min Density in% of theoretical Syntron MAW electropower volume. vibrator Sintered and ground (1) 100—20 + 100 (4) 3.3 2134; 19.05 x 0.89 58-62 69 Sintered and ground 60—3 + 8 3.0 2438; 14.48 x 0.76 - 8 —20 +100 —200 Sintered and ground 60—34- 8 3.2438; 14.48 x 0.76 - 84 —20 +100 Sintered and ground 60— 63.2 2438; 14.48 x 0.76 - 87 18—35 +6 22—200 Brand, malen (2) 60— 6+ 1.8 2438; 14.48 x 0.76 82 90 —35 +6 —100 + 200 Fire, times 60— 14 + 1.0 914; 19.05 x 0.89 - 83.1 —65 +100 —200 + 3 Electrolytic (3) In the form shown 1.6 914; 19.05 x 0.89 53 6 Particle density 95% of the theoretical 99% e 93% * Particle size range for forged industry elements PRT reactors.

For jamforelse innehaller denna tabell resultaten av nagra fa provningar med en Syntronvibrationspackare, vilken joke kan anvandas for utfOrande av detta speciella forfarande. Det m. framhallas, att de forbattrade resultaten uppnas dven om det komprimerade pulvret yore malet. For comparison, this table contains the results of a few tests with a Syntron vibration packer, which joke can be used to perform this particular procedure. It is to be noted that the improved results are obtained even if the compressed powder is ground.

Det Or aven tydligt, att genom lampligt val av partikelstorleksfraktioner kan en presskropp er- som Or tillrackligt tat f Or att direkt kunna anvandas i en karnreaktor. Den maximala tathet som erhallits vid anvandning av brand och malen urandioxid var 90 % av den teoretiska, medan maximitatheten vid anvandning av sintrad och krossad urandioxid var 87 %. It is also clear that by suitable choice of particle size fractions, a compact can be sufficiently used to be used directly in a nuclear reactor. The maximum density obtained when using fire and ground uranium dioxide was 90% of the theoretical, while the maximum density when using sintered and crushed uranium dioxide was 87%.

Upptackten att taheten kan tikas genom ratt val av omildena f Or partikelstorleksfraktionerna utgor visserligen ingen del av foreliggande uppfinming men av tabellen framgar det, att det Or viktigt, att anvanda ett flertal distinkta fraktioner inorn olika storleksomraden for att astadkomma en presskropp, som Or tillrackligt tat for att den skall kunna anvthidas direkt i en karnreaktor. Tabellen visar tydligt, och de partikelstorlekar, som anvandas ler att astadkomma den stOrsta fortatningen avensom de nagot Iran de optimala avvikande resultaten. Grunderna f Or val av optimala storleksfraktioner for tillampning av fiireliggande uppfinning Oro de som redan tidigare anvants mom foreliggande tekniska omra.de. The discovery that the density can be ticked by the correct choice of the particles for the particle size fractions does not form part of the present invention, but the table shows that it is important to use a number of distinct fractions within different size ranges to achieve a compact, which is sufficiently so that it can be used directly in a nuclear reactor. The table clearly shows, and the particle sizes used smile to achieve the greatest condensation even if they somewhat Iran the optimal deviating results. The grounds for choosing the optimal size fractions for the application of the present invention Concerns those already used in the present technical field.

En liten tathetsokning av ungefar 2 V„ kan astadkommas genom sanksmidning av rOret med dess genom vibration komprimerade Den salunda framstallda presskroppens tathet Or stone an den, som kan astadkommas genom sankessmidning av ror med tillstampat innehall. Denna tathetsokning Or emellertid i allmanhet joke tillracklig for att motivera den darmed forbundna kostnadsokningen. Den enbart genom vibration packade staven duger utan nagon extra behaudling. A small increase in density of about 2 V „can be achieved by forging the tube with a suction compressed by the vibration of the thus produced press body Or stone an den, which can be achieved by forging of tubes with stamped contents. However, this increase in density is generally sufficient to justify the associated cost increase. The rod packed only by vibration is sufficient without any extra maintenance.

Orsaken till forbattringen är visserligen icke fullt klarlagd, men troligen astadkommas genom fOrstarkt vibration vid resonansfrekvens periodis-_ ka utvidgningar och sammandragningar av behallarvaggarna, sa att dessa komprimera det inneslutna materialet genom en slags »sjalvsankessmidning#. Genom vibrationen orientera sig enskilda partiklar in i atkomliga haligheter och komprimeras genom den av behallarvaggarna utovade »sanksmidesverkaim sa att det blir onodigt att utova yttre slag- eller pressverkan. Den vertikala vibrationsamplituden i rorets ovre ande Or manga ganger storre On amplituden av de vibrationer, som rbret bibringas av vibratorn. Sanksmidesverkan uppstar, nar vibrationerna vandra uppat i roret. Although the cause of the improvement is not fully understood, it is probably caused by excessive vibration at resonant frequency periodic expansions and contractions of the container cradles, so that they compress the enclosed material by a kind of "self-forging". Through the vibration, individual particles orient themselves into accessible cavities and are compressed by the "sink forging" exerted by the container cradles, so that it becomes unnecessary to exert external impact or compression action. The vertical vibration amplitude in the upper end of the tube Or many times greater On the amplitude of the vibrations, which the tube is imparted by the vibrator. The sink-forging effect occurs when the vibrations travel upwards in the rudder.

Den huvudsakliga fordelen med fOreliggande uppfinning vinnes darigenom att roret vibreras med sin resonansfrekvens. A.nnu en teknisk f Or-Mitring vinnes darigenom, att vibreringen anpassas efter resonansfrekvensen, nar denna andrar sig, alit efter som materialet komprimeras. 42044 I ett med kornformigt bransle fyllt ror är resonansfrekvensen lagre an i ett tomt rbr. Ett 1,22 meters tomt ror med resonansfrekvensen 750 hz har resonansfrekvensen 365 hz, ndr det innehaller ett kilogram lost urandioxidpulver, och resonansfrekvensen 440 hz, nar pulvret sammanpackas till ungefar 85 % av den teoretiska tdtheten. Fiir att astadkomma detta kan vibrationen sattas igang vid 365 hz och periodtalet okas till 440 hz, medan pulvret komprimeras. The main advantage of the present invention is gained by vibrating the tube with its resonant frequency. Another technical feature is obtained by the vibration being adapted to the resonant frequency when it changes, albeit as the material is compressed. 42044 In a rudder filled with granular fuel, the resonant frequency is lower than in an empty tube. A 1.22 meter empty tube with a resonant frequency of 750 Hz has a resonant frequency of 365 Hz, when it contains one kilogram of lost uranium dioxide powder, and a resonant frequency of 440 Hz, when the powder is packed to approximately 85% of the theoretical density. To achieve this, the vibration can be started at 365 Hz and the period number increased to 440 Hz, while the powder is compressed.

Ytterligare en forbattring a.stadkommes genom att »svepa» Over ett stort frekvensomrade. Detta galler i synnerhet for ror, vilkas grundresonansfrekvens Or lag, sasom.de langa roren i de angivna exemplen. Detta beror pa den okning av fortatningen, som erhalles genom vibrering vid en av grundresonansfrekvensens overtoner. Vibrering med frekvenser bade Over och under resonansfrekvensen Ora emellertid effekt, oavsett huruvida nagon Overton uppnas, i det att presskroppens tathet och homogenitet okas. Denna forbattring beror pi de olika stora partiklarnas benagenhet att orientera sig i blandningen genom vibrering med olika amplituder och frekvenser. A further improvement is achieved by "sweeping" over a large frequency range. This applies in particular to tubes, the fundamental resonant frequency of which is as long as the tubes in the examples given. This is due to the increase in the gain obtained by vibration at one of the harmonics of the fundamental resonant frequency. Vibration with frequencies both above and below the resonant frequency Ora, however, has an effect, regardless of whether any Overton is achieved, in that the tightness and homogeneity of the compact is increased. This improvement is due to the tendency of the different large particles to orient themselves in the mixture by vibration with different amplitudes and frequencies.

NastfOljande tabell askadliggor den okade fOrbattringen av fortatningen, som erhalles nar de olika utfOrandena av forfarandet enligt uppfinningen tillampas. En av UO2-partiklar bestaende blandning anvandes, vilkens tathet Or 95 % av den teoretiska, och vilken packas i ett 1,22 meters zirkal1oy-2-ror. The following table illustrates the increased improvement of the concentration which is obtained when the various embodiments of the process according to the invention are applied. A mixture consisting of UO2 particles was used, the density of which is 95% of theory, and which is packed in a 1.22 meter circular tube.

Tabell IL MetodUOr tathet i % av den teoretiska Vanlig vibrationspackare (100 volt) 60 hz; tryck upptill och nedtill (impact top and bottom)73,6 Riklig elektromagn. vibrator (2 kW, ± 340 kp stbt) 60 hz77,1 Initialresonansfrekvens (365 hz) 80,0 Initial- till slutresonansfrekvens; (365 till 450 hz)82,6 Frekvenssvep enl. foreliggande forfarande; 100 till 5000 hz84,8 Aft de tatheter, som erhallas i denna provserie Oro tamligen sma, beror ph att partikeltatheten Or nagot mindre On den optimala, och pa partikelstorleksfordelningen. For den genom frekvenssvep behandlade branslestaven uppnaddes emellertid for PRTR gallande data. Korta stavar Oro joke sa tata som stavar med full dvs. ungefar 2,4 meters langd p0 grund av de langre rorens stone egna sankessmidningsformaga. Table IL MetodUOr density in% of the theoretical Standard vibration packer (100 volts) 60 hz; pressure top and bottom 73.6 Abundant amount of electricity. vibrator (2 kW, ± 340 kp stbt) 60 hz77.1 Initial resonant frequency (365 hz) 80.0 Initial to final resonant frequency; (365 to 450 hz) 82.6 Frequency sweep acc. present procedure; 100 to 5000 hz84.8 Of the densities obtained in this test series of concern are rather small, ph is due to the fact that the particle density is slightly smaller than the optimum, and on the particle size distribution. However, for the frequency sweep treated by frequency sweeping, bile data were obtained for PRTR. Short spells Oro joke said tata as spells with full ie. approximately 2.4 meters long due to the longer rudder stone's own sankessmgingningsformaga.

Sattet enligt foreliggande uppfinning kan Oven tillampas pa korta, tjocka ror, Oven om de genom uppfinningen vunna fordelarna Oro mest patagliga nar det Or fragan am langa, smala branslestavar. Aven i kor La ror blir fortatningen battre On den, som erhalles genom vibrering utan hansyn till resonansfrekvensen. The method according to the present invention can also be applied to short, thick tubes. Although the advantages gained by the invention are most suitable when it comes to long, narrow branch rods. Even in chorus La ror, the condensation becomes better On den, which is obtained by vibration without hansyn to the resonant frequency.

Den beskrivna, speciella apparaten lampar sig visserligen synnerligen val for utforande av sattet enligt uppfinningen, men uppfinningens rackvidd Or icke begransad hartill, Vad som behovs Or en skakapparat, medelst vilken det rOr, som skall fyllas, skakas vertikalt kontinuerligt med varie-, rande amplitud, frekvens och acceleration. Although the described special apparatus is particularly suitable for carrying out the set according to the invention, the scope of the invention is not limited thereto. What is needed is a shaker, by means of which the tube to be filled is shaken vertically continuously with varying amplitude. , frequency and acceleration.

Uppfinningen Or sarskilt tillamplig pa framstallning av brdnslestavar som innehalla plutonium, vilkas tillverkning ph hittills brukligt satt Or mycket halsovadlig. Uppfinningen lampar sig Oven synnerligen val for framstallning av bransleelement med jamn och star tathet, vilka ha komplex geometri och joke kunna smidas i sanke. Knippen av rorformiga, invandigt kylda bransleelement kunna till exempel latt framstallas genom fOrfarandet enligt foreliggande uppfinning. The invention is particularly applicable to the production of fuel rods containing plutonium, the manufacture of which has hitherto been customary. The invention is particularly suitable for the production of fuel elements with smoothness and rigidity, which have complex geometry and jokes that can be forged. The bundles of tubular, internally cooled fuel elements can, for example, be easily produced by the method according to the present invention.

FOr karnreaktorer avsedda keramiska bransleelement framstallda genom vibrationskomprimeringsmetoden enligt uppfinningen Oro tillrackligt tata for att -kunna anvandas i en reaktor direkt utan nagot ytterligare komprimeringsforfarande. Bransleelementen behova ej riktas och ingen betydande bearbetning erfordras for att Ora deras utsidor jamna. Forfarandet Or ytterst enkelt, och tar endast kort tid i ansprak, varjamte maskineriet for dess utforande Or ganska billigt. Detta forfarande passar sarskilt val for behandling av plutoniumhaltiga branslen och bransleelement med komplex geometri. Nuclear reactor elements designed for nuclear reactors manufactured by the vibration compression method according to the invention are sufficiently sufficient to be able to be used in a reactor directly without any further compression process. The fuel elements do not need to be aligned and no significant machining is required to smooth their outer surfaces. The procedure is extremely simple, and takes only a short time, and the machinery for its execution is quite inexpensive. This procedure is particularly suitable for the treatment of plutonium-containing industries and industry elements with complex geometry.

Uppfinningens rackvidd skall joke anses vara begransad till de harmed beskrivna detaljerna, utan den omfattar Oven modifikationer darav avensom andra utforingsformer. The scope of the invention should be considered to be limited to the details described herein, but it also includes modifications thereof as well as other embodiments.

Claims

Patent claim:

A method of producing a fuel element for a nuclear reactor, wherein sintered or cast uranium dioxide is ground and salted into a plurality of particle size fractions and selected fractions, where the star size ratio between the particle size of successive fractions is started, ground and introduced into a vertical metal tube. the metal tube using a vibrator which vibrates the tube in the vertical direction is vibrated at a frequency equal to and fines the basic resonant frequency varying with the compaction of the powder has the system comprising the tube and the powder in the assembled layer.

2. Set according to claim 1, characterized in that the metal tube Oven is vibrated at frequencies 204 above and below said fundamental resonant frequency.

3. According to patent claim 2, characterized in that the vibration frequency ova-fiftr the fundamental resonant frequency forms a harmonic oscillation to the fundamental resonant frequency.

Set according to claim 3 using a vibrator which vibrates the rudder in the vertical direction, characterized by the following steps:

5. vibration with low power and at a frequency Over the fundamental resonant frequency;

6. rapid reduction of the vibration frequency down to the basic resonant frequency of the rudder;

7. increasing the power and changing the vibration frequency Over and around the fundamental resonant frequency several times;

8. reduction of the vibration frequency to a value below the fundamental resonant frequency of the rudder;

9. increasing the vibration frequency to the fundamental resonant frequency value and changing the vibrating frequency to the value on Orme pages of the fundamental resonant frequency several times;

10. 'Turning the vibration frequency to a harmonic shift value f Or the fundamental resonant frequency and Turning the vibration frequency to the value on each side of the harmonic frequency several times, and

11. Increasing the vibration frequency to a frequency value, which Egger significantly exceeds the fundamental resonant frequency. Request publications: UK Patent Nos. 580,490, 706,476.