SE204552C1

SE204552C1 -

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Publication number: SE204552C1
Authority: SE
Publication date: 1965-01-01

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KLASS INTERNATIONELLSVENSK G2121 g:21/ PATENT- OCH REGISTRERINGSVERKET Ans. 744/1959 inkom den 27/1 1959 utlagd den 2019 196 UNITED STATES ATOMIC ENERGY COMMISSION, WASHINGTON, D.C. USA Bransleelement for karnreaktorer UppfInnare: C W Wheelock och E B Baumeister Prioritet begdrd juin den 28 januari 1958 (USA) Foreliggande uppfinning avser ett bransleelement for karnreaktorer, innehallande ett flertal i sidled och i axiell led mot varandra anliggande bransleplattor bestaende av ett flertal sektioner fOrsedda med i tvarsnitt rektanguldra distansfenor, vilka begransa axiella kylmedelskanaler. Uppfinningen avser sarskilt ett fbrbattrat bransleelement for en reaktor modererad med organiskt material. CLASS INTERNATIONAL SWEDISH G2121 g: 21 / PATENT AND REGISTRATION AGENCY Ans. 744/1959 was filed on 27/1 1959 issued on 2019 196 UNITED STATES ATOMIC ENERGY COMMISSION, WASHINGTON, D.C. USA Fuel Element for Nuclear Reactors Inventors: CW Wheelock and EB Baumeister Priority Requested June 28, 1958 (USA) cross-section rectangular spacers, which delimit axial coolant channels. In particular, the invention relates to an improved fuel element for a reactor moderated with organic material.

Hittills ha platta hransleelement eller element av MTR-typ foreslagits for reaktorer modererade med organiskt material. Ett typiskt plattelement omfattar Hera la.nga, nagot krokta eller plana plattor, som besta av var sin karna av en uranaluminiumlegering eller en sinterkropp av UO, och rostfritt stal med en tunn kapsling av aluminium eller rostfritt stal, sa att man far en sandwiehkonstruktion. Kapslingen liar till andamal att halla kvar fissionsprodukter i branslet och att skydda uranet mot korrosion eller andra skador orsakade av kylmedlet. Platarna arc monterade i langsgaende spar i en ihalig, rektangular ram och aro fastsvetsade eller fastlodda i denna, sã att man far en mekaniskt stabil enhet. To date, flat grating elements or MTR-type elements have been proposed for reactors moderated with organic material. A typical slab element comprises Hera long, slightly curved or flat slabs, each consisting of a core of a uranium-aluminum alloy or a sintered body of UO, and stainless steel with a thin casing of aluminum or stainless steel, so that a sand construction is obtained. The enclosure is intended to keep fission products in the industry and to protect the uranium against corrosion or other damage caused by the coolant. The plates arc mounted in longitudinal grooves in a hollow, rectangular frame and are welded or soldered in it, so that a mechanically stable unit is obtained.

En olagenhet med nuvarande plattbransleelement är, att det varme, som alstras i bransleplattorna, leder till att plattornas temperatur blir hOgre an kylmedlets temperatur. De delar av bransleelementet, i vilka inget varme alstras, lianas vid kylmedlets temperatur. Den skillnad i vdrmentvidgning, som beror pa temperaturskillnader mellan dessa delar, kan resultera i svara varmespanningar. Problemet blir annu svarare vid reaktorer kylda med en organisk vatska, emedan denna har samre varmeledningsformaga an flytande metall eller vatten. Om man icke kompenserar for varmegradienterna, upptrada svara spanningar, som leda till kastningar, heta flackar och bransleelementets sammanbrott. Vi-dare dr plattans varmeoverforingsyta joke tillfredsstallande for bortforande av en tillracklig mangd \time. Detta skulle krava antingen en Okning av kylmedlets hastighet eller hogre arbetstemperatur. En olming av pumpkapaciteten skulle Oka anldggningskostnaderna. Det organiska me-diet sonderdelas vidare snabbt Over en viss temperatur. A disadvantage of current plate fuel elements is that the heat generated in the fuel plates leads to the temperature of the plates being higher than the temperature of the coolant. The parts of the fuel element in which no heat is generated are heated at the temperature of the coolant. The difference in thermal expansion, which is due to temperature differences between these parts, can result in severe thermal stresses. The problem becomes even more pronounced with reactors cooled with an organic liquid, because this has a more common thermal conductivity than liquid metal or water. If one does not compensate for the heat gradients, black voltages occur, which lead to throws, hot flats and the collapse of the fuel element. Furthermore, the heat transfer surface of the plate is satisfactory for the removal of a sufficient amount of time. This would require either an increase in refrigerant speed or a higher operating temperature. An increase in pumping capacity would increase installation costs. The organic medium is further subdivided rapidly over a certain temperature.

Uppfinningen syftar till att undanroja dessa olagenheter. Della ernas genom att varje sektion i bransleelementet bestar av en karna av klyvbart material med kapsling, att de rektanguldra distansfenorna Oro utformade pa varje plattsektions bada sidor och Oro i kontakt med distansfenorna pa ndrliggande sektioner, att ett flertal axiellt kontinuerliga kylfenor dro anordnade pa varje sektion mellan distansfenorna och delvis inskjuta i kylkanalerna samt arc forstallda 1 forhallande till kylfenorna pa den motstaende sidan av motsthende sektion, och att branslelementet är fOrsett med organ for fasthallning av sektionerna p. sh. Ott, att distansfenorna hallas i anliggning med varandra och sektionerna fasthallas parallella med varandra och mot relativ rorelse i sidled. The invention aims to eliminate these illegalities. Divided by each section of the fuel element consisting of a core of fissile material with casing, the rectangular spacer fins Oro formed on both sides of each plate section and Oro in contact with the spacer fins on adjacent sections, a plurality of axially continuous cooling fins being arranged on each section between the spacer fins and partially insert into the cooling ducts and arc formed 1 relative to the cooling fins on the opposite side of the opposite section, and that the branch element is provided with means for holding the sections p. sh. Note that the spacer fins are held in abutment with each other and the sections are held parallel to each other and against relative lateral movement.

Uppfinningen beskrives nedan narmare med hdnvisning till bifogade ritningar, vilka som exempel visa nagra utforingsformer. Fig. 1 Or en delvis skuren sidovy av bransleelementet. Fig. 2 visar ett snitt efter linjen 2-2 i fig. I. Fig. 3 visar en del av fig. 2 i storre skala. Fig. 4 och 5 visa delar av fig. 1 i stone skala. Fig. 6-8 visa en annan utforingsform av uppfinningen. Fig. 6 visar ett snitt genom en bransleplatta. Fig. 7 visar ett knippe sadana bransleplattor och fig. 8 dr en perspektivvy av ett bransleelement. The invention is described in more detail below with reference to the accompanying drawings, which show, by way of example, some embodiments. Fig. 1 Or a partially cut side view of the fuel element. Fig. 2 shows a section along the line 2-2 in Fig. I. Fig. 3 shows a part of Fig. 2 on a larger scale. Figs. 4 and 5 show parts of Fig. 1 on a stone scale. Figs. 6-8 show another embodiment of the invention. Fig. 6 shows a section through a fuel plate. Fig. 7 shows a bundle of such fuel plates and Fig. 8 shows a perspective view of a fuel element.

Fig. 1 visar bransleelementet 1 i sitt lage i en reaktorkarna. Elementet Or nedsankt genom ett 2 byre galler 2, vilket tjanstgOr som styrning under insattningen och driften. Huvudstycket 3 bildar en ihalig rektangel fOrsedd med nabbar 4 avsedda for ingrepp med ett hanteringsdon for insattning och uttagning av bransleelementet. Fenor 5 hindra hanteringsdonet att skada bransleelementkomponenterna. Andstycket 6 ar ihaligt och avsmalnande och dess ansats 7 vilar pa ansatsen 8 i en munstycksplat 9 for reglering av kylmedlets stromning, vilken i sin tur vilar pa reaktorns bottengallerplatta 10. Tack vare denna konstruktion kunna bransleelementen och munstycksplatama utbytas separat. Konstruktionen av toppoch bottenorganen är icke vasentlig utan kan modifieras pa olika satt i beroende av den anvanda mekanismen for hantering av branslet och av gallerplattornas form. Bransleplattorna 11 aro rektangulara och anordnade parallellt med varandra. Plattorna aro icke sten infasta genom lodning eller svetsning sasom vid tidigare konstruktioner. Varje platta bares i stallet av en tvarbalk 12, sasom visas i fig. 5. Varje plattas byre ande pressas nedht med en fjader 13, sasom visas i fig. 1. Fjaderns nedre dude slutar i en skalformig bricks 14. Fjadern 13 reglerar bransleplattornas 11 rorelse, sâ att bransleplattorna komma att forlangas axielft mot fjadern vid varje sldllnad I varmeutvidgningen. Plattorna lianas salunda i huvudsak flytande och bransleelementbrott pa grund av kastning undvikes genom att expansion ar mojlig. Holj et 15 till den bransleinnehallande delen av enheten samt topp- och bottenorganen 3 och 6 iiverlappa varandra och aro hopsvetsade till bildning av en behallare for bransleplattorna. Fig. 1 shows the fuel element 1 in its position in a reactor core. The element Or is lowered through a 2 byre grid 2, which serves as a control during deployment and operation. The main piece 3 forms a hollow rectangle provided with hubs 4 intended for engagement with a handling device for insertion and removal of the fuel element. Fins 5 prevent the handler from damaging the fuel element components. The headpiece 6 is hollow and tapered and its shoulder 7 rests on the shoulder 8 in a nozzle plate 9 for regulating the flow of the coolant, which in turn rests on the bottom grid plate of the reactor 10. Thanks to this construction the fuel elements and the nozzle plates can be exchanged separately. The construction of the top and bottom members is not essential but can be modified in different ways depending on the mechanism used for handling the industry and the shape of the grid plates. The fuel plates 11 are rectangular and arranged parallel to each other. The tiles are not stone fixed by soldering or welding as in previous constructions. Each plate is carried in the place of a crossbeam 12, as shown in Fig. 5. The bearing end of each plate is pressed down with a spring 13, as shown in Fig. 1. The lower dude of the spring ends in a shell-shaped brick 14. The spring 13 regulates the fuel plates 11 movement, so that the fuel plates will be required axially to the spring at each stroke in the thermal expansion. The tiles are thus mainly liquid and fuel element breakage due to throwing is avoided by allowing expansion. Holes 15 to the fuel-containing part of the unit and the top and bottom members 3 and 6 overlap each other and are welded together to form a container for the fuel plates.

Bransleplattorna visas i fig. 2 och 3. Plattornas 11 kapsling 16 har fenor 17 och en karna av klyvhart material. Dessa fenor Oka varmetivergAngen starkt (med en faktor av 21), i forhallande till det slata plattelementet under samma forhallanden. Sasom framgar av fig. 2 och 3 har plattan en karna av klyvbart material och periodiskt aterkommande, rektangulara, ratvinkliga fenor 19, som aro nagot langre an de spetsiga fenorna 20. De rakskurna fenorna 19 pa efterfOljande plattor ligga i kontakt med varandra, varigenom de fordela bransleplattorna och bilda ett lateralt stod for dessa, medan det axiella stodet astadkommes av fjadern 13 och styrstangerna 12. Om plattoma bojas, komma de rakskurna fenorna att fOrhindra allvarlig igensattning av kylmedelskanalerna. Sasom framgar av fig. 2 aro de skarpa fenorna 19 p. efterfoljande plattor och pa motsatta sidor av samma platta icke anordnade mitt for varandra utan med nagon forstallning. Harigenom forbattras flodet av kylmedlet langs bransleplattorna. Fenorna 21 vid bransleplattornas andar intill holjet 15 aro kortare an de aterstaende fenorna. Delta her visat sig forbattra varmeovergangen frau elementet genom att mOjliggora starkare node av kylmedel kings hOljet. Plattans iiversida har tva smala fenor, medan undersidan har tre pa grand av forstallningen mellan efterfoljande plattor. Del ma vidare framhallas, att bransleplattan i fig. 3 endast utgor halften av en bransle- platta i fig. 2 och att motsvarande andar ph tva bransleplattor av den i fig. 3 visade typen motas rygg mot rygg mittpa plattan enligt fig. 2 under bildning av en sammansatt platta. Anledningen hartill ar, att det är ldttare att tillverka del kortare stycket genom strangpressning, sasom kommer att beskrivas i det foljande. Detta ar emellertid icke vasentligt utan en enkel bransleplatta kan tillverkas fOr att overspanna hela bredden av bransleelementramen. Bransleplattan kan vidare vara sammansatt av flera kortare stycken, exempelvis fyra, i langdriktningen. The fuel plates are shown in Figs. 2 and 3. The casing 16 of the plates 11 has fins 17 and a core of cleft hard material. These fins increase the heat dissipation strongly (by a factor of 21), in relation to the smooth plate element under the same conditions. As can be seen from Figures 2 and 3, the plate has a core of fissile material and periodically recurring, rectangular, right-angled fins 19, which are slightly longer than the pointed fins 20. The straight-cut fins 19 on subsequent plates are in contact with each other, whereby the distribute the fuel plates and form a lateral stand for them, while the axial stand is provided by the spring 13 and the guide rods 12. If the plates are bent, the straight-cut fins will prevent severe clogging of the coolant channels. As can be seen from Fig. 2, the sharp fins 19 on subsequent plates and on opposite sides of the same plate are not arranged opposite each other but with some pre-arrangement. This improves the flow of the coolant along the fuel plates. The fins 21 at the spirals of the fuel plates adjacent the housing 15 are shorter than the remaining fins. Delta here has been shown to improve the heat transfer from the element by enabling stronger node of the coolant king's oil. The upper side of the plate has two narrow fins, while the underside has three on the grand of the arrangement between subsequent plates. It must further be emphasized that the fuel plate in Fig. 3 constitutes only half of a fuel plate in Fig. 2 and that corresponding spirits of two fuel plates of the type shown in Fig. 3 are received back to back in the middle of the plate according to Fig. 2 during formation. of a composite plate. The reason for this is that it is easier to manufacture the shorter piece by extrusion, as will be described in the following. However, this is not essential, but a simple fuel plate can be manufactured to span the entire width of the fuel element frame. The fuel plate can furthermore be composed of several shorter pieces, for example four, in the longitudinal direction.

Bransleplattan 22 i den altemativa utforingsformen enligt fig. 6-8 har sasom visas i fig. 6 liknande rakskurna och spetsiga fenor 23 och 24, vilka fylla samma uppgifter, varvid de rakskurna fenorna utgUra distansorgan. Donna platta avviker emellertid genom att den liar en relativt stone, rakskuren slutfena 25 forsedd med not och spout 26 och 27. Noten och sponten eller liknande lasmedel mellan efterfoljande bransleplattor 22 ingripa lasande i varandra sasom visas i fig. 7, sa. att stabiliteten forbattras. Plattorna s5.ttas samman till ett bransleknippe 28 och lianas ihop med periferiella band 29 av samma material som kapslingen. Med undantag for andstycket aro fenorna intill banden icke 1 kontakt med dessa, sa att kylmedlet kan passera. Fiera sadana knippen 28, exempelvis fyra, inforas sedan i ett ihaligt, rektangulart lit* 30, som visas i fig, 8, Knippena aro endast staplade pd varandra i holjet och icke f Orbundna med detsamma eller med varandra. Varje skillnad i varmeutvidgning mellan hOljet 30 och knippena 28 kan salunda upptagas utan att spanningar inforas. En tvarbalk och en fjader eller nO.got annat bojligt stodorgan liknande del i samband med foregaende utforingsform beskrivna kan aven anvandas for att forhindra axiell rorelse eller skrammel, sarskilt om kylmedlet strommar uppit och icke nedat. Den nedatriktade stromningen medverkar till stabiliteten och kan Ora det mojligt aft utesluta fjadrarna i bagge utforingsformerna. Bransleelementet enligt fig. 8 her ett annat huvudstycke och andstycke 31 och 32 5.n utforingsformen enligt fig. 1. Kylinedlets stromfling genom elementet antydes med pilar. The fuel plate 22 in the alternative embodiment according to Figs. 6-8 has, as shown in Fig. 6, similar straight-cut and pointed fins 23 and 24, which fulfill the same tasks, the straight-cut fins constituting spacers. The donna plate differs, however, in that it has a relatively stone, straight-cut end fin 25 provided with tongue and groove 26 and 27. The tongue and groove or similar welding means between successive fuel plates 22 engage lasers in each other as shown in Fig. 7, sa. that stability is improved. The plates are assembled into an industry bundle 28 and lined together with peripheral bands 29 of the same material as the enclosure. With the exception of the duck piece, the fins next to the straps are not in contact with them, so that the coolant can pass. Four such bundles 28, for example four, are then inserted into a hollow, rectangular lit * 30, as shown in Fig. 8, The bundles are only stacked on top of each other in the housing and not connected to the same or to each other. Any difference in thermal expansion between the housing 30 and the bundles 28 can thus be absorbed without stresses being introduced. A crossbeam and a spring or some other flexible support member similar to the part described in connection with the preceding embodiment can also be used to prevent axial movement or rattling, especially if the coolant flows upwards and not downwards. The downward flow contributes to the stability and can possibly exclude the springs in the ram embodiments. The fuel element according to Fig. 8 here is another main piece and duck pieces 31 and 32 5. In the embodiment according to Fig. 1. The flow of the coolant through the element is indicated by arrows.

Branslekarnan 18 omfattar en karna av klyvbart material, sasom uran eller plutonium, antingen i form av en metall eller en legering, sasom uran-aluminium och urantorium, eller ett keramiskt material, sasom uranoxid eller -karbid, eller ett sintermaterial, exempelvis bestaende av UO, och rostfritt stal eller aluminium. Uranmetallen kan vara naturlig eller anrikad pa klyvbar isotop U233 eller U2. I en organiskt modererad reaktor '3 är uranet anrikat till nagra fa procent IJ2", exempelvis c:a 2 %. Kapslingen bestar av nagon korrosionsbestandig metall eller legering, sasom aluminium, rostfritt sta.l eller zirkonium. Med hansyn till att aluminium har relativt la.gt tvarsnitt for absorption av termiska neutroner, och i stort sett har tillfredsstallande metallurgiska egenskaper i en organiskt modererad reaktor, foredras denna metall i fOreliggande fall. For forhindrande av omsattning mellan uran och aluminium, som kan resultera i bildningen av UAL, anbringas ett tunt, exempelvis 124u tjockt skikt av nickel elektrolytiskt pa uranet som en diffusionssparr. The fuel core 18 comprises a core of fissile material, such as uranium or plutonium, either in the form of a metal or an alloy, such as uranium-aluminum and urantorium, or a ceramic material, such as uranium oxide or carbide, or a sintered material, for example consisting of UO , and stainless steel or aluminum. The uranium metal may be natural or enriched in fissile isotope U233 or U2. In an organically moderated reactor '3, the uranium is enriched to a few percent IJ2 ", for example about 2%. The enclosure consists of some corrosion-resistant metal or alloy, such as aluminum, stainless steel or zirconium. Considering that aluminum has a relative A low cross section for the absorption of thermal neutrons, and having substantially satisfactory metallurgical properties in an organically moderated reactor, this metal is preferred in the present case. thin, for example 124u thick layer of nickel electrolytically on the uranium as a diffusion barrier.

Den grundlaggande bransleplattan kan tillverkas pa olika satt och det valda tillverkningsfOrfarandet är joke av storre betydelse. Aluminiumkapslingen har salunda med framgang strangpressats med eller utan karnan. Om kapslingen strangpressas utan karnan, kan karnmaterialet sedan inforas i det bildade halrummet i plattan, varefter kapslingen bindes metallurgiskt vid karnan genom varmpressning i en dyna med asar, som svara mot kapslingens form. Enligt ett annat forfarande kan aluminium utfallas galvaniskt pa det klyvbara materialet, varefter de Onskade fenorna astadkommes genom varmpressning i en lamplig dyna. Olika metallurgiska forfaranden kunna tillampas. Ett exempel beskrives i Cunninghams uppsats enligt ovan. The basic fuel plate can be manufactured in different ways and the chosen manufacturing procedure is a joke of greater importance. The aluminum housing has thus successfully been extruded with or without the core. If the housing is extruded without the core, the core material can then be introduced into the formed cavity in the plate, after which the housing is metallurgically bonded to the core by hot pressing in a pad with axes, which correspond to the shape of the housing. According to another method, aluminum can be galvanized on the fissile material, after which the desired fins are obtained by hot pressing in a suitable pad. Different metallurgical procedures can be applied. An example is described in Cunningham's essay as above.

I det foljande beskrives ett exempel pa dimensionerna for bransleelementet enligt fig. 1-6 for anvandning i den ovan beskrivna organiskt modererade reaktorn utan andring av denna reaktor. In the following, an example of the dimensions of the fuel element according to Figs. 1-6 for use in the organically moderated reactor described above without modifying this reactor is described.

Exemp el 1. Example 1.

Totala dimensioner76 x 76 x 91 cm (aktiv langd) Total langd med huvud och andstycken Antal plattor per bransleelement Bra.nsleplatta Karna Kapsling HOlj e Fenor bredd mellanrum hOjd distansorganens langd Fjader Bransleladdning (totalt uran per platta) per element reaktorns laddning (36 element) 152 cm 6 (8 sektioner per platta) 7,1 cm X 7,1 cm bredd 3,3 mm tjoek uranmetall anrikad till 2,9 % U2 0,51 mm aluminium 0,76 mm rostfritt sta.]. 4 fenor per cm 1,27 mm vid basen 1,27 mm c:a 4,2 mm 1,27 mm langd 5,08 cm 3,95 kg 23,70 kg 853,2 kg Exempel 2. Detta beskriver anvandningen av ett bransleelement enligt foreliggande uppfinning i en annan organiskt modererad effektreaktor med foljande egenskaper: Effektalstring elektrisk nettoeffekt11 400 kW elektrisk bruttoeffekt12 500 » termisk bruttoeffekt45 500 » Vattenangforhallanden angtryck29,05 kp/cm2 angans temperatur288° G angalstring73 400 kg/h matarvattnets temperatur vid full belastning170° C kondensorkylvattnets temperatur21° C Reaktorkylning kylmedelterfenyl kylmedlets tryck8,4 kp/cm2 systemets konstruktions- tryck21 kp/cm2 kylmedlets intradestemp. 288° C kylmedlets uttradestemp. 316° C kylmedlets stromnings- hastighet2,3 kg/h antal primarslingor2 totalt tryckfall3,5 kpiem2 kylmedlets cirkulationstid 40 s tryck- och avgasnings- flodeshastighet200 spm Reaktoregenskaper. max. termiskt neutron- node3,0 x 13 n/cm2-s genomsnittligt termiskt neutronflode2,0 X 33 n/cm2-s maximalt varmeflode21,5 x 4 kcal/h.m2 bransleelementens totala varmevaxlingsyta730 m2 anrikning pa U21,8 % laddning av 132120 kg Bransleelementens egenskaper. Total dimensions76 x 76 x 91 cm (active length) Total length with head and duck pieces Number of plates per fuel element Brain plate Plate Enclosure Housing Fins width spacing height distance of the spacers Feather Fuel charge (total uranium per plate) per element reactor charge (36 elements) 152 cm 6 (8 sections per plate) 7.1 cm X 7.1 cm width 3.3 mm thick uranium metal enriched to 2.9% U2 0.51 mm aluminum 0.76 mm stainless steel.]. 4 fins per cm 1.27 mm at the base 1.27 mm approx. 4.2 mm 1.27 mm length 5.08 cm 3.95 kg 23.70 kg 853.2 kg Example 2. This describes the use of a fuel elements according to the present invention in another organically moderated power reactor with the following properties: Power generation electric net power11 400 kW gross electrical power12 500 »thermal gross power45 500» Water vapor ratio ang pressure 29.05 kp / cm2 angular temperature288 ° G angular string73 400 kg / h feed temperature C condenser cooling water temperature 21 ° C Reactor cooling coolant terphenyl coolant pressure 8.4 kp / cm2 system design pressure 21 kp / cm2 coolant inlet temp. 288 ° C refrigerant outlet temp. 316 ° C refrigerant flow rate2,3 kg / h number of primary loops2 total pressure drop3,5 kpiem2 refrigerant circulation time 40 s pressure and degassing flow rate200 ppm Reactor properties. max. thermal neutron node3.0 x 13 n / cm2-s average thermal neutron flux2.0 X 33 n / cm2-s maximum heat flow21.5 x 4 kcal / h.m2 total heat exchange area of fuel elements 730 m2 enrichment on U21.8% loading of 132120 kg Properties of the fuel elements.

Karna3,3 mm uranmetall anrikad till 1,8 °,/,, 132" Kapsling0,51 mm aluminium Holje12,1 x 12,1 x 0,076 cm Fenor4 fenor/cm bredd1,27 mm vid basen aystand mellan fenorna 1,27 mm hojd3,8 mm Bransleplatta137 x 12,1 cm 4 Elementets totala langd 174 cm fj &ler5,1 cm huvudstycke19 cm andstycke13 cm antal plattor per element20 (4 sektioner per platta) antal bransleelement i karnan63 De ovan beskrivna utforingsformerna kunna modifieras, utan att man dad& overskrider uppfinningens ram. Core3.3 mm uranium metal enriched to 1.8 °, / ,, 132 "Enclosure0.51 mm aluminum Housing12.1 x 12.1 x 0.076 cm Fins4 fins / cm width1.27 mm at the base aystand between the fins 1.27 mm height3 .8 mm Fuel plate137 x 12.1 cm 4 The total length of the element 174 cm & more 5.1 cm headpiece19 cm duct 13 cm number of plates per element20 (4 sections per plate) number of fuel elements in karnan63 The embodiments described above can be modified without overdoing & exceeding the framework of the invention.

Claims

Patent claim:

Fuel elements for nuclear reactors, containing a plurality of laterally and axially adjacent fuel plates consisting of a plurality of sections provided with cross-sectional spacer fins, which define three coolant channels, characterized in that each section consists of a cleavable material. that the rectangular spacer fins are formed on the sides of each plate section and are in contact with the spacer fins on adjacent sections, that a plurality of axially continuous cooling fins are arranged on each section between the spacer fins and partially project into the cooling channels and are shaped in relation to the cooling fins on the opposite the side of the opposite section and that the fuel element is provided with means for holding the sections in such a way that the spacer fins are held in abutment with each other and the sections are held parallel to each other and against relative lateral movement.

Fuel element according to claim 1, characterized in that some cooling fins at the side edges of each fuel plate are shorter than the other cooling fins on other parts of the surface of the plate. Request publications: Patent documents from Sweden 148 754. Other publications: International conference on the peaceful uses of atomic energy. 1955. Geneva. Proceedings. Vol. 9. New York 1956. (United Nations publications), pp. 203-207, 221-230.