EP0081660B1 - Moulded body for encapsulating spent nuclear fuel elements, and process for manufacturing this body - Google Patents
Moulded body for encapsulating spent nuclear fuel elements, and process for manufacturing this body Download PDFInfo
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- EP0081660B1 EP0081660B1 EP82109826A EP82109826A EP0081660B1 EP 0081660 B1 EP0081660 B1 EP 0081660B1 EP 82109826 A EP82109826 A EP 82109826A EP 82109826 A EP82109826 A EP 82109826A EP 0081660 B1 EP0081660 B1 EP 0081660B1
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- Prior art keywords
- nuclear fuel
- rods
- moulding
- fuel rods
- moulding according
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- 238000000034 method Methods 0.000 title claims description 9
- 239000002915 spent fuel radioactive waste Substances 0.000 title claims description 8
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 239000003758 nuclear fuel Substances 0.000 claims description 32
- 239000011159 matrix material Substances 0.000 claims description 28
- 239000002184 metal Substances 0.000 claims description 19
- 229910052751 metal Inorganic materials 0.000 claims description 19
- 239000000843 powder Substances 0.000 claims description 18
- 238000000465 moulding Methods 0.000 claims description 17
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 14
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 13
- 229910002804 graphite Inorganic materials 0.000 claims description 12
- 239000010439 graphite Substances 0.000 claims description 12
- WWNBZGLDODTKEM-UHFFFAOYSA-N sulfanylidenenickel Chemical compound [Ni]=S WWNBZGLDODTKEM-UHFFFAOYSA-N 0.000 claims description 8
- 238000003825 pressing Methods 0.000 claims description 7
- 229910052759 nickel Inorganic materials 0.000 claims description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 5
- 230000007774 longterm Effects 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 238000004804 winding Methods 0.000 claims description 3
- 238000004873 anchoring Methods 0.000 claims 5
- ZZUFCTLCJUWOSV-UHFFFAOYSA-N furosemide Chemical compound C1=C(Cl)C(S(=O)(=O)N)=CC(C(O)=O)=C1NCC1=CC=CO1 ZZUFCTLCJUWOSV-UHFFFAOYSA-N 0.000 claims 3
- 239000005864 Sulphur Substances 0.000 claims 2
- YGHCWPXPAHSSNA-UHFFFAOYSA-N nickel subsulfide Chemical compound [Ni].[Ni]=S.[Ni]=S YGHCWPXPAHSSNA-UHFFFAOYSA-N 0.000 claims 1
- 239000000446 fuel Substances 0.000 description 9
- 238000005260 corrosion Methods 0.000 description 6
- 230000007797 corrosion Effects 0.000 description 6
- 238000003860 storage Methods 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 230000017525 heat dissipation Effects 0.000 description 3
- 230000010354 integration Effects 0.000 description 3
- 238000002386 leaching Methods 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 239000012611 container material Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000007580 dry-mixing Methods 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 239000002901 radioactive waste Substances 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 239000010891 toxic waste Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/28—Treating solids
- G21F9/34—Disposal of solid waste
- G21F9/36—Disposal of solid waste by packaging; by baling
Definitions
- the invention relates to a cylindrical or polygonal shaped body made of graphite and nickel sulfide for the safe long-term integration of spent nuclear fuel rods in their original shape or deformed shape and a method for producing such shaped bodies.
- Spent fuel elements from nuclear reactors have to be disposed of for a final disposal after a certain period of time.
- Two ways were investigated worldwide, namely the reprocessing of the fuel elements with the return of the fuels to the fuel element production as well as the separation and final storage of the fission products (highly active waste) and alternatively the direct final storage of the spent fuel elements.
- highly active waste is generated, which must be safely stored in suitable geological formations for 1,000 years or more.
- DE-A-2818781 describes a method for the environmentally safe storage of spent nuclear fuel rods, in which the nuclear fuel rods are bent and the packages thus obtained are placed in a protective container.
- the nuclear fuel rods are preferably U-shaped or deformed into a wound roll. This method has the disadvantage that containers are required and the heat dissipation from the nuclear fuel rods to the outside is relatively poor.
- the molded body contains anchor plates in the head and foot area and in the core fuel rod-free zones inside parallel to the main axis of the molded body in the anchor plates attached metal rods.
- metal rods with a macroscopically rough surface in order to improve the mechanical bond between the graphite / nickel sulfide matrix and the rods.
- the shaped body contains the nickel sulfide predominantly in the form of Ni 3 S 2 . This further increases the resistance to corrosion and leaching.
- the moldings generally contain 10 to 75% by weight of graphite and 25-90% by weight of nickel sulfide, preferably at least 80% thereof in the form of Ni 3 S 2 as the matrix material.
- the moldings according to the invention have an extraordinarily high mechanical integrity, so that the requirements specified by the repository are completely met.
- These moldings are preferably produced by first inserting a matrix powder of graphite, nickel and sulfur into a die, then an anchor plate with attached metal rods, then deformed or undeformed nuclear fuel rods together with matrix powder, another anchor plate with attached metal rods and finally again matrix powder is introduced and pressed at temperatures above 100 ° C, the matrix being pre-compressed in the area of the stored nuclear fuel rods before pressing and the metal rods being attached to the anchor plates only in areas above or below which there are no nuclear fuel rods.
- the pressing is advantageously carried out at temperatures between 400 and 500 ° C.
- the anchor plates are pressed in such a way that the metal rods slide past one another within the core and edge regions free of nuclear fuel during compression and anchor themselves in the hardening matrix.
- the mechanical integrity of the shaped body - in particular in the case of tensile and bending stress - is significantly increased, so that it is possible to incorporate the nuclear fuel rods in any shape (e.g. wound, kinked or in original dimensions).
- the nuclear fuel rods are advantageously deformed into disk-shaped spirals, with a central region of preferably. Leaves 80 mm diameter free. In the production of these fuel rod spirals, it has proven to be advantageous to keep the winding spacing ⁇ 6 mm.
- the compression ratios of the matrix in the areas containing and free of nuclear fuel are matched to one another in such a way that the residual formability is the same in both areas. This makes it possible to achieve a uniform integral density over the entire length of the molded body.
- the method according to the invention advantageously also allows individual fuel rod spirals to be incorporated into the graphite-nickel sulfide matrix.
- Such disks can be stacked on top of each other in a container suitable for final storage, so that they can be easily retrieved or also be stored for final storage as required.
- the discs can be provided with a central gripping hole for easier retrievability.
- contaminated nuclear fuel rod casings can also be integrated in this way.
- Figure 1 shows schematically a shaped body according to the invention in an exemplary embodiment in longitudinal section
- Figure 2 shows a nuclear fuel rod in spiral form.
- the molded body contains in the head area (2) and in the foot area (3) an anchor plate (1), on which metal rods (4) are fastened, and only on the areas of the anchor plates (1) between which there are none when pressing the molded body Nuclear fuel rods (5) are located.
- the nuclear fuel rods (5) are therefore preferably deformed into disc-shaped spirals (6) with a rod-free center (7), so that the metal rods (4) can also be arranged in the center in addition to the outer region of the shaped body.
- a mixture of 43.7% by weight of finely powdered natural graphite, 15% by weight of finely ground sulfur and 41.3% by weight of nickel metal powder was prepared as the starting powder for the matrix by dry mixing.
- the nuclear fuel rods had an inner diameter of 8 mm and were filled with sintered U0 2 pellets with a density of 10.4 g / cm 3 .
- the individual nuclear fuel rods are inserted into suitable steel tubes and these are sealed on both sides.
- the nuclear fuel rods clamped at one end were wound up with the aid of a suitable device to form spirals with a maximum outer winding spacing of .6 mm and a diameter of approximately 260 mm.
- a layer of matrix powder was poured into a steel matrix with a diameter of 300 mm, this was cold pre-compressed and an anchor plate with 5 metal rods (3 on the periphery, 2 on the inside) was placed on it. Another - 10 mm thick - matrix powder layer was applied to the anchor plate.
- a nuclear fuel rod spiral was placed thereon and then matrix powder was filled in at a height which corresponded approximately to the layer thickness of a nuclear fuel rod spiral. In the center and in the edge area of the spiral, the matrix powder content was increased by approx. 30% by additional pre-compression.
- a further 39 spirals were arranged one above the other in layers in accordance with the working step described.
- the second anchor plate with staggered metal rods was inserted. Additional matrix powder was filled in above this anchor plate - equivalent to the amount that was filled in at the beginning of the process.
- the final pressing was carried out with a pressure of 50 MN / m 2 .
- the temperature was raised to 450 ° C. with continued pressure. After cooling to 300 ° C, the molded body was ejected.
- the matrix powder was prepared analogously to Example 1. Encapsulated approximately 5 m long Nuclear fuel rods were bent 20 times so that the width was 450 mm-250 mm at a height.
- the kinked fuel rods were integrated in a square matrix. After filling in the first matrix powder layer and the anchor plate with 2 external metal rods, 6 kinked nuclear fuel rods were arranged and the space was filled with matrix powder. After inserting the second anchor plate with staggered metal rods, this was overlaid with matrix powder - equivalent to the amount that was filled in at the beginning of the process.
- the matrix properties of the finished molded article correspond to the properties of the molded article described in Example 1.
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- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Powder Metallurgy (AREA)
- Piles And Underground Anchors (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
- Sealing Material Composition (AREA)
- Press Drives And Press Lines (AREA)
Description
Die Erfindung betrifft einen zylindrischen oder polygonalen Formkörper aus Graphit und Nickelsulfid zur sicheren Langzeiteinbindung von abgebrannten Kernbrennstoffstäben in Originalform oder verformter Gestalt und ein Verfahren zur Herstellung solcher Formkörper.The invention relates to a cylindrical or polygonal shaped body made of graphite and nickel sulfide for the safe long-term integration of spent nuclear fuel rods in their original shape or deformed shape and a method for producing such shaped bodies.
Abgebrannte Brennelemente aus Kernreaktoren müssen nach einer gewissen Zeit der Zwischenlagerung einer Endbeseitigung zugeführt werden. Weltweit wurden dazu zwei Wege untersucht, nämlich die Wiederaufarbeitung der Brennelemente mit Rückführung der Brennstoffe in die Brennelementfertigung sowie Abtrennung und Endlagerung der Spaltprodukte (hochaktiver Abfall) und alternativ die direkte Endlagerung der abgebrannten Brennelemente. In jedem Fall entsteht hochaktiver Abfall, der 1 000 Jahre und mehr sicher in geeignete geologische Formationen eingelagert werden muß.Spent fuel elements from nuclear reactors have to be disposed of for a final disposal after a certain period of time. Two ways were investigated worldwide, namely the reprocessing of the fuel elements with the return of the fuels to the fuel element production as well as the separation and final storage of the fission products (highly active waste) and alternatively the direct final storage of the spent fuel elements. In any case, highly active waste is generated, which must be safely stored in suitable geological formations for 1,000 years or more.
Zum sicheren Langzeit-Einschluß solcher abgebrannter Brennelemente sind zahlreiche Behältertypen vorgeschlagen worden, die die geforderten Bedingungen, wie dichter Einschluß bei den auftretenden Drücken und Temperaturen oder Korrosionsfestigkeit gegen Salzlaugen, gut erfüllen. Als Behältermaterial werden vielerlei metallische und nichtmetallische Werkstoffe verwendet.For the safe long-term containment of such spent fuel elements, numerous types of containers have been proposed that meet the required conditions, such as tight containment at the pressures and temperatures that occur or corrosion resistance against brine. Various metallic and non-metallic materials are used as container material.
Da Graphit eine hervorragende Korrosionsbeständigkeit besitzt, ist vorgeschlagen worden (DE-A-2942092), Behälter mit einer Korrosionsschutzschicht aus Graphit zu versehen. Da Graphitformkörper der für die Aufnahme eines Brennelementes notwendigen Abmessungen bisher weder gas- noch flüssigkeitsdicht herzustellen sind, ist eine anschließende Beschichtung mit Pyrokohlenstoff oder Siliciumkarbid vorgesehen. Nach dem Einfüllen des Brennelements soll der beschichtete Behälter mit einem gleichermaßen beschichteten Deckel gas- und flüssigkeitsdicht verschlossen werden. Hierbei sollen Graphitdichtungen bzw. geeignete Klebemittel zum Einsatz kommen. Ein wesentlicher Nachteil dieses Behälterkonzepts ist der ausserordentlich hohe technische Aufwand, der für die Herstellung und Beschichtung solcher Behälter mit großen Abmessungen notwendig ist. Außerdem lassen sich so große Formkörper nicht mit den geforderten Qualitätsansprüchen beschichten.Since graphite has excellent corrosion resistance, it has been proposed (DE-A-2942092) to provide containers with a corrosion protection layer made of graphite. Since graphite moldings of the dimensions necessary for accommodating a fuel assembly have hitherto not been able to be made gas-tight or liquid-tight, a subsequent coating with pyrocarbon or silicon carbide is provided. After the fuel element has been filled in, the coated container is to be closed in a gas-tight and liquid-tight manner with an equally coated lid. Here graphite seals or suitable adhesives should be used. A major disadvantage of this container concept is the extraordinarily high technical outlay required for the production and coating of such containers with large dimensions. In addition, such large moldings cannot be coated with the required quality requirements.
Es ist auch bekannt, zur Einbindung von radioaktiven und toxischen Abfällen Formkörper aus einer Kohlenstoffmatrix herzustellen (DE-A-2917437), indem man die Abfälle mit einem Gemisch aus Graphitpulver und e iem Bindemittel bei höheren Temperaturen presst. Als Bindemittel verwendet man hierbei vorzugsweise Nickelsulfid. Solche Formkörper sind sehr dicht und besitzen eine gute Korrosions-und Auslaugebeständigkeit, insbesondere gegenüber Salzlösungen.It is also known, for the integration of radioactive and toxic waste molded article of a Ko h lenstoffmatrix produce (DE-A-2917437), which involves pressing the wastes with a mixture of graphite powder and e IEM binder at higher temperatures. Nickel sulfide is preferably used as the binder. Such moldings are very dense and have good resistance to corrosion and leaching, in particular to salt solutions.
In der DE-A-2818781 wird ein Verfahren zur umweltsicheren Lagerung von abgebrannten Kernbrennstoffstäben beschrieben, bei dem die Kernbrennstoffstäbe gebogen und die so erhaltenen Pakete in einen Schutzbehälter untergebracht werden. Vorzugsweise werden dabei die Kernbrennstoffstäbe U-förmig oder zu einer aufgewickelten Rolle verformt. Dieses Verfahren hat den Nachteil, daß man Behälter benötigt und die Wärmeabfuhr von den Kernbrennstoffstäben nach außen relativ schlecht ist.DE-A-2818781 describes a method for the environmentally safe storage of spent nuclear fuel rods, in which the nuclear fuel rods are bent and the packages thus obtained are placed in a protective container. The nuclear fuel rods are preferably U-shaped or deformed into a wound roll. This method has the disadvantage that containers are required and the heat dissipation from the nuclear fuel rods to the outside is relatively poor.
Es ist auch bekannt, die verformten Kernbrennstoffstäbe mit Tonerde und einem dünnen Stahlmantel isostatisch zu einem Block zu verpressen (Sprechsaai 113 (1980), 753-766), der endgelagert werden kann. Auch hier ist jedoch das Problem der Wärmeabfuhr nicht optimal gelöst. Außerdem ist die mechanische Integrität nicht für alle denkbaren Einlagerungsfälle ausreichend.It is also known to isostatically compress the deformed nuclear fuel rods with alumina and a thin steel jacket into a block (Redesaai 113 (1980), 753-766), which can be finally disposed of. Here too, however, the problem of heat dissipation is not optimally solved. In addition, the mechanical integrity is not sufficient for all conceivable storage cases.
Es war daher Aufgabe der vorliegenden Erfindung, zylindrische oder polygonale Formkörper aus Graphit und Nickelsulfid zur sicheren Langzeit-Einbindung von abgebrannten Kernbrennstoffstäben in Originalform oder in verformter Gestalt zu schaffen, die eine gute Wärmeabführung gewährleisten, eine gute Korrosions- und Auslaugebeständigkeit besitzen und eine hohe mechanische Integrität aufweisen.It was therefore an object of the present invention to provide cylindrical or polygonal shaped bodies made of graphite and nickel sulfide for the safe long-term integration of spent nuclear fuel rods in their original shape or in a deformed shape, which ensure good heat dissipation, good corrosion and leaching resistance and high mechanical strength Show integrity.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß der Formkörper im Kopf- und Fußbereich Ankerplatten und in kernbrennstoffstabfreien Zonen im Innern parallel zur Hauptachse des Formkörpers in den Ankerplatten befestigte Metallstäbe enthält.This object is achieved in that the molded body contains anchor plates in the head and foot area and in the core fuel rod-free zones inside parallel to the main axis of the molded body in the anchor plates attached metal rods.
Für die Ankerplatten und die Metallstäbe kann man alle üblichen Materialien verwenden, vorzugsweise benutzt man jedoch Stahl.All usual materials can be used for the anchor plates and the metal rods, but steel is preferably used.
Es ist vorteilhaft, Metallstäbe mit einer makroskopisch rauhen Oberfläche zu verwenden, um die mechanische Bindung zwischen Graphit/Nickelsulfid-Matrix und den Stäben zu verbessern.It is advantageous to use metal rods with a macroscopically rough surface in order to improve the mechanical bond between the graphite / nickel sulfide matrix and the rods.
Als vorteilhaft hat es sich auch herausgestellt, wenn der Formkörper das Nickelsulfid überwiegend in Form von Ni3S2 enthält. Dadurch wird die Korrosions- und Auslaugebeständigkeit weiter erhöht. Die Formkörper enthalten im allgemeinen als Matrixwerkstoff 10 bis 75 Gew.-% Graphit und 25-90 Gew.-% Nickelsulfid, vorzugsweise mindestens 80 % davon in Form von Ni3S2.It has also proven to be advantageous if the shaped body contains the nickel sulfide predominantly in the form of Ni 3 S 2 . This further increases the resistance to corrosion and leaching. The moldings generally contain 10 to 75% by weight of graphite and 25-90% by weight of nickel sulfide, preferably at least 80% thereof in the form of Ni 3 S 2 as the matrix material.
Die erfindungsgemäßen Formkörper besitzen eine außerordentlich hohe mechanische Integrität, so daß die durch das Endlager vorgegebenen Anforderungen restlos erfüllt werden.The moldings according to the invention have an extraordinarily high mechanical integrity, so that the requirements specified by the repository are completely met.
Die Herstellung dieser Formkörper erfolgt vorzugsweise dadurch, daß in eine Matrize zuerst ein Matrixpulver aus Graphit, Nickel und Schwefel, dann eine Ankerplatte mit daran befestigten Metallstäben, anschließend verformte oder unverformte Kernbrennstoffstäbe zusammen mit Matrixpulver, eine weitere Ankerplatte mit daran befestigten Metallstäben und abschließend nochmals Matrixpulver eingebracht und bei Temperaturen oberhalb 100 °C gepresst wird, wobei die Matrix im Bereich der eingelagerten Kernbrennstoffstäbe vor dem Pressen vorverdichtet wird und die Metallstäbe auf den Ankerplatten nur in Bereichen angebracht werden, oberhalb bzw. unterhalb derer sich keine Kernbrennstoffstäbe befinden. Vorteilhafterweise erfolgt das Pressen bei Temperaturen zwischen 400 und 500 °C.These moldings are preferably produced by first inserting a matrix powder of graphite, nickel and sulfur into a die, then an anchor plate with attached metal rods, then deformed or undeformed nuclear fuel rods together with matrix powder, another anchor plate with attached metal rods and finally again matrix powder is introduced and pressed at temperatures above 100 ° C, the matrix being pre-compressed in the area of the stored nuclear fuel rods before pressing and the metal rods being attached to the anchor plates only in areas above or below which there are no nuclear fuel rods. The pressing is advantageously carried out at temperatures between 400 and 500 ° C.
Die Ankerplatten werden hierbei so eingepresst, daß die Metallstäbe innerhalb der kernbrennstoffstabfreien Zentral- und Randbereiche bei der Verdichtung aneinander vorbeigleiten und sich in der aushärtenden Matrix verankern. Dadurch wird die mechanische Integrität des Formkörpers - insbesondere bei Zug- und Biegebeanspruchung - wesentlich erhöht, sodaß es möglich ist, die Kernbrennstoffstäbe in beliebiger Form (z. B. gewickelt, geknickt oder in Originalabmessungen) einzubinden.The anchor plates are pressed in such a way that the metal rods slide past one another within the core and edge regions free of nuclear fuel during compression and anchor themselves in the hardening matrix. As a result, the mechanical integrity of the shaped body - in particular in the case of tensile and bending stress - is significantly increased, so that it is possible to incorporate the nuclear fuel rods in any shape (e.g. wound, kinked or in original dimensions).
Vorteilhafterweise werden die Kernbrennstoffstäbe zu scheibenförmigen Spiralen verformt, wobei man einen Zentralbereich von vorzugsweise . 80 mm Durchmesser freiläßt. Bei der Herstellung dieser Brennstabspiralen hat es sich als vorteilhaft erwiesen, den Windungsabstand < 6 mm zu halten.The nuclear fuel rods are advantageously deformed into disk-shaped spirals, with a central region of preferably. Leaves 80 mm diameter free. In the production of these fuel rod spirals, it has proven to be advantageous to keep the winding spacing <6 mm.
Die Verdichtungsverhältnisse der Matrix in den kernbrennstoffstabhaltigen und -freien Bereichen werden so aufeinander abgestimmt, daß die Restberformbarkeit in beiden Bereichen gleich groß ist. Dadurch gelingt es, eine gleichmäßige integrale Dichte über der gesamten Formkörperlänge zu erzielen.The compression ratios of the matrix in the areas containing and free of nuclear fuel are matched to one another in such a way that the residual formability is the same in both areas. This makes it possible to achieve a uniform integral density over the entire length of the molded body.
Neben einer Vielzahl von Kernbrennstoffstäben lassen sich mit dem erfindungsgemäßen Verfahren vorteilhafterweise auch einzelne Brennstabspiralen in die Graphit-Nickelsulfid-Matrix einbinden. Solche Scheiben können in einem für die Endlagerung geeigneten Behälter übereinandergestapelt werden, so daß sie je nach Bedarf leicht rückholbar oder auch endlagerfähig sind. Zur leichteren Rückholbarkeit können die Scheiben mit einem zentralen Greifloch versehen sein.In addition to a large number of nuclear fuel rods, the method according to the invention advantageously also allows individual fuel rod spirals to be incorporated into the graphite-nickel sulfide matrix. Such disks can be stacked on top of each other in a container suitable for final storage, so that they can be easily retrieved or also be stored for final storage as required. The discs can be provided with a central gripping hole for easier retrievability.
Neben intakten Kernbrennstoffstäben können auf diese Weise auch kontaminierte Kernbrennstoffstabhüllen eingebunden werden.In addition to intact nuclear fuel rods, contaminated nuclear fuel rod casings can also be integrated in this way.
Die Abbildung 1 zeigt schematisch einen erfindungsgemäßen Formkörper in beispielhafter Ausführungsform im Längsschnitt, Abbildung 2 einen Kernbrennstoffstab in Spiralform.Figure 1 shows schematically a shaped body according to the invention in an exemplary embodiment in longitudinal section, Figure 2 shows a nuclear fuel rod in spiral form.
Der Formkörper enthält im Kopfbereich (2) und im Fußbereich (3) je eine Ankerplatte (1), auf denen Metallstäbe (4) befestigt sind, und zwar nur auf den Bereichen der Ankerplatten (1), zwischen denen sich beim Pressen des Formkörpers keine Kernbrennstoffstäbe (5) befinden. Die Kernbrennstoffstäbe (5) werden daher vorzugsweise zu scheibenförmigen Spiralen (6) mit einem stabfreien Zentrum (7) verformt, sodaß die Metallstäbe (4) neben dem Außenbereich des Formkörpers auch im Zentrum angeordnet werden können.The molded body contains in the head area (2) and in the foot area (3) an anchor plate (1), on which metal rods (4) are fastened, and only on the areas of the anchor plates (1) between which there are none when pressing the molded body Nuclear fuel rods (5) are located. The nuclear fuel rods (5) are therefore preferably deformed into disc-shaped spirals (6) with a rod-free center (7), so that the metal rods (4) can also be arranged in the center in addition to the outer region of the shaped body.
Anhand der folgenden Beispiele sollen die erfindungsgemäßen Formkörper und das erfindungsgemäße Verfahren näher erläutert werden.The moldings according to the invention and the method according to the invention are to be explained in more detail with reference to the following examples.
Als Ausgangspulver für die Matrix wurde eine Mischung aus 43,7 Gew.-% feingepulvertem Naturgraphit, 15 Gew.-% feingemahlenem Schwefel und 41,3 Gew.-% Nickelmetallpulver durch Trockenmischen hergestellt. Die Kernbrennstoffstäbe hatten einen Innendurchmesser von 8 mm und waren mit gesinterten U02-Pellets mit einer Dichte von 10,4 g/cm3 gefüllt. Die einzelnen Kernbrennstoffstäbe werden in geeignete Stahlrohre gesteckt und diese beidseitig dicht verschlossen. Die an einem Ende eingespannten Kernbrennstoffstäbe wurden mit Hilfe einer hierzu geeigneten Vorrichtung zu Spiralen mit einem maximalen äußeren Windungsabstand von , 6 mm und einem Durchmesser von ca. 260 mm aufgewickelt.A mixture of 43.7% by weight of finely powdered natural graphite, 15% by weight of finely ground sulfur and 41.3% by weight of nickel metal powder was prepared as the starting powder for the matrix by dry mixing. The nuclear fuel rods had an inner diameter of 8 mm and were filled with sintered U0 2 pellets with a density of 10.4 g / cm 3 . The individual nuclear fuel rods are inserted into suitable steel tubes and these are sealed on both sides. The nuclear fuel rods clamped at one end were wound up with the aid of a suitable device to form spirals with a maximum outer winding spacing of .6 mm and a diameter of approximately 260 mm.
Zum Einbinden der Spiralen wurde in eine Stahlmatrize mit 300 mm Durchmesser eine Schicht aus Matrixpulver eingefüllt, diese kalt vorverdichtet und darauf eine Ankerplatte mit 5 Metallstäben (3 an der Peripherie, 2 im Innern) gelegt. Auf die Ankerplatte wurde eine weitere - 10 mm dicke - Matrixpulverschicht aufgebracht. Darauf wurde eine Kernbrennstoffstabspirale gelegt und dann Matrixpulver in einer Höhe eingefüllt, die etwa der Schichtdicke einer Kernbrennstoffstabspirale entsprach. Im Zentrum und im Randbereich der Spirale wurde der Matrixpulvergehalt durch zusätzliche Vorverdichtung um ca. 30 % angehoben. Zum Aufbau des Formkörpers wurden weitere 39 Spiralen gemäß dem beschriebenen Arbeitsschritt schichtenweise übereinander angeordnet. Am oberen Ende der letzten Spirale wurde die zweite Ankerplatte mit versetzt angeordneten Metallstäben eingesetzt. Oberhalb dieser Ankerplatte wurde weiteres Matrixpulver eingefüllt - äquivalent der Menge, die zu Beginn des Prozesses unten eingefüllt wurde. Nach dem Erwärmen auf 130 °C erfolgte das Fertigpressen mit einem Preßdruck von 50 MN/m2. Zur Umsetzung des Schwefel/Nickel-Gemisches zum Ni3S2 wurde die Temperatur bei anhaltenden Druck auf 450 °C angehoben. Nach dem Abkühlen auf 300 °C wurde der Formkörper ausgestoßen.To bind the spirals, a layer of matrix powder was poured into a steel matrix with a diameter of 300 mm, this was cold pre-compressed and an anchor plate with 5 metal rods (3 on the periphery, 2 on the inside) was placed on it. Another - 10 mm thick - matrix powder layer was applied to the anchor plate. A nuclear fuel rod spiral was placed thereon and then matrix powder was filled in at a height which corresponded approximately to the layer thickness of a nuclear fuel rod spiral. In the center and in the edge area of the spiral, the matrix powder content was increased by approx. 30% by additional pre-compression. In order to build up the molded body, a further 39 spirals were arranged one above the other in layers in accordance with the working step described. At the top of the last spiral, the second anchor plate with staggered metal rods was inserted. Additional matrix powder was filled in above this anchor plate - equivalent to the amount that was filled in at the beginning of the process. After heating to 130 ° C., the final pressing was carried out with a pressure of 50 MN / m 2 . To convert the sulfur / nickel mixture to Ni 3 S 2 , the temperature was raised to 450 ° C. with continued pressure. After cooling to 300 ° C, the molded body was ejected.
Der fertiggepreßte Formkörper hatte folgende Eigenschaft :
- 0 = 300 mm
- H = 760 mm
- Matrixdichte : 3,3 g/cm3
- Dichte : 97 % der theoretischen Dichte
- Wärmeleitfähigkeit: 0,8 W/cm - K
- Linearer thermischer Ausdehnungskoeffizient: 9,2 mm/m - K
- Druckfestigkeit: 107 MN/m2
- 0 = 300 mm
- H = 760 mm
- Matrix density: 3.3 g / cm 3
- Density: 97% of the theoretical density
- Thermal conductivity: 0.8 W / cm - K
- Linear coefficient of thermal expansion: 9.2 mm / m - K
- Compressive strength: 107 MN / m 2
Die Matrixpulverherstellung erfolgte analog dem Beispiel 1. Etwa 5 m lange eingekapselte Kernbrennstoffstäbe wurden 20mal geknickt, so daß die Breite bei einer Höhe von 450 mm-250 mm betrug.The matrix powder was prepared analogously to Example 1. Encapsulated approximately 5 m long Nuclear fuel rods were bent 20 times so that the width was 450 mm-250 mm at a height.
Das Einbinden der geknickten Brennstäbe erfolgte in einer Vierkantmatrize. Nach dem Einfüllen der ersten Matrixpulverschicht und der Ankerplatte mit 2 außenliegenden Metallstäben wurden 6 geknickte Kernbrennstoffstäbe angeordnet und der Zwischenraum mit Matrixpulver ausgefüllt. Nach dem Einbringen der zweiten Ankerplatte mit versetzt angeordneten Metallstäben wurde diese mit Matrixpulver überschichtet - äquivalent zu der Menge, die zu Beginn des Prozesses unten eingefüllt wurde.The kinked fuel rods were integrated in a square matrix. After filling in the first matrix powder layer and the anchor plate with 2 external metal rods, 6 kinked nuclear fuel rods were arranged and the space was filled with matrix powder. After inserting the second anchor plate with staggered metal rods, this was overlaid with matrix powder - equivalent to the amount that was filled in at the beginning of the process.
Die Pressung erfolgte wie in Beispiel 1.The pressing was carried out as in Example 1.
Die Matrixeigenschaften des fertiggepreßten Formkörpers stimmen mit den Eigenschaften des in Beispiel 1 beschriebenen Formkörpers überein.The matrix properties of the finished molded article correspond to the properties of the molded article described in Example 1.
Claims (8)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3144755 | 1981-11-11 | ||
| DE3144755A DE3144755C2 (en) | 1981-11-11 | 1981-11-11 | Shaped body for incorporating spent nuclear fuel rods and process for its manufacture |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0081660A1 EP0081660A1 (en) | 1983-06-22 |
| EP0081660B1 true EP0081660B1 (en) | 1985-02-20 |
Family
ID=6146108
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP82109826A Expired EP0081660B1 (en) | 1981-11-11 | 1982-10-23 | Moulded body for encapsulating spent nuclear fuel elements, and process for manufacturing this body |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0081660B1 (en) |
| JP (1) | JPS5888698A (en) |
| BR (1) | BR8206478A (en) |
| DE (2) | DE3144755C2 (en) |
| ES (2) | ES268417Y (en) |
| FI (1) | FI74836C (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3344525A1 (en) * | 1983-12-09 | 1985-06-20 | Kernforschungsanlage Jülich GmbH, 5170 Jülich | METHOD FOR STORING BURNED FUEL ELEMENTS |
| JPS6145298A (en) * | 1984-08-09 | 1986-03-05 | カシオ計算機株式会社 | Electronic musical instrument |
| DE3532155C1 (en) * | 1985-09-10 | 1987-02-19 | Kernforschungsanlage Juelich | Ultimately disposable bundle and method for producing it |
| AT385435B (en) * | 1986-03-07 | 1988-03-25 | Oesterr Forsch Seibersdorf | METHOD AND DEVICE FOR EMBEDDING AND, IF NECESSARY, REACTIVATING, IN PARTICULAR, TOXIC AND / OR RADIOACTIVE SUBSTANCES OR. DISEASE |
| DE19700651C1 (en) * | 1997-01-10 | 1998-09-03 | Siemens Ag | Compression of control and absorber elements to be disposed of from light water reactors |
| DE102009044963B4 (en) * | 2008-11-10 | 2011-06-22 | ALD Vacuum Technologies GmbH, 63450 | Graphite matrix blocks with inorganic binder suitable for storage of radioactive waste and method of making the same |
| ES2530463T3 (en) | 2008-11-10 | 2015-03-03 | Ald Vacuum Techn Gmbh | Graphite-based matrix material and inorganic binders suitable for the definitive storage of radioactive waste, procedure for its preparation, its preparation and use |
| US8502009B2 (en) | 2008-11-26 | 2013-08-06 | Ald Vacuum Technologies Gmbh | Matrix material comprising graphite and an inorganic binder suited for final disposal of radioactive waste, a process for producing the same and its processing and use |
| RU2403633C1 (en) * | 2009-07-27 | 2010-11-10 | Открытое акционерное общество "Российский концерн по производству электрической и тепловой энергии на атомных станциях" (ОАО "Концерн Росэнергоатом") | Method for storage of spent nuclear fuel |
| DE102010003289B4 (en) * | 2010-03-25 | 2017-08-24 | Ald Vacuum Technologies Gmbh | Containers for the storage of radioactive waste and process for its production |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2375695A1 (en) * | 1976-12-21 | 1978-07-21 | Asea Ab | PROCESS FOR THE TREATMENT OF RADIOACTIVE WASTE |
| SE413712B (en) * | 1977-05-10 | 1980-06-16 | Asea Ab | WANT TO INCLUDE USED NUCLEAR FUEL WASTE IN A SAFETY CONTAINER |
| DE2846845A1 (en) * | 1978-10-27 | 1980-05-08 | Battelle Institut E V | Radioactive fission prod. final storage in glass block - poured around metal filler, e.g. wires to prevent cracking on cooling in mould |
| DE2917437C2 (en) * | 1979-04-28 | 1983-11-17 | Nukem Gmbh, 6450 Hanau | Procedure for incorporating radioactive and toxic waste |
| DE2942092C2 (en) * | 1979-10-18 | 1985-01-17 | Steag Kernenergie Gmbh, 4300 Essen | Final storage containers for radioactive waste, in particular irradiated nuclear reactor fuel elements |
-
1981
- 1981-11-11 DE DE3144755A patent/DE3144755C2/en not_active Expired
-
1982
- 1982-09-29 FI FI823335A patent/FI74836C/en not_active IP Right Cessation
- 1982-10-23 DE DE8282109826T patent/DE3262446D1/en not_active Expired
- 1982-10-23 EP EP82109826A patent/EP0081660B1/en not_active Expired
- 1982-11-09 JP JP57195399A patent/JPS5888698A/en active Pending
- 1982-11-09 BR BR8206478A patent/BR8206478A/en unknown
- 1982-11-10 ES ES1982268417U patent/ES268417Y/en not_active Expired
- 1982-11-10 ES ES517238A patent/ES517238A0/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| DE3144755A1 (en) | 1983-05-26 |
| DE3144755C2 (en) | 1984-06-28 |
| ES8402671A1 (en) | 1984-02-01 |
| EP0081660A1 (en) | 1983-06-22 |
| BR8206478A (en) | 1983-09-27 |
| FI74836B (en) | 1987-11-30 |
| JPS5888698A (en) | 1983-05-26 |
| FI823335A0 (en) | 1982-09-29 |
| DE3262446D1 (en) | 1985-03-28 |
| FI823335L (en) | 1983-05-12 |
| FI74836C (en) | 1988-03-10 |
| ES268417Y (en) | 1983-12-01 |
| ES268417U (en) | 1983-05-16 |
| ES517238A0 (en) | 1984-02-01 |
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