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
  • G21F1/00—Shielding characterised by the composition of the materials
  • G21F1/02—Selection of uniform shielding materials
  • G21F1/10—Organic substances; Dispersions in organic carriers
  • G21F1/103—Dispersions in organic carriers
  • G21F1/106—Dispersions in organic carriers metallic dispersions

Definitions

• the invention relates to a shielding material for shielding radiation, in particular of radioactive radiation, in particular of ⁇ and v-rays, and X-ray radiation and neutron radiation according to the preamble of claim 1.
• the object of the present invention is to provide a shielding high shielding, in particular against ß- and y-radiation, X-rays and neutron radiation, which does not have the above-mentioned disadvantages of the shielding materials previously used.
• the invention proposes a heavy metal-polymer mixture as shielding material.
• the heavy metal / polymer mixture preferably has a high density, preferably in the range between 4 and 10 g / cm 3 .
• the heavy metal-polymer mixture is a heavy metal powder-polymer mixture or a heavy metal granule-polymer mixture or a heavy metal powder / heavy metal granule-polymer mixture.
• a heavy metal of high density and having a high capture cross section is used for ⁇ and ⁇ rays, X-ray and neutron radiation, which is preferably bismuth, iron, barite or tungsten.
• the metal portion of the metal-polymer mixture consists of bismuth powder, iron powder or barite powder or tungsten powder or bismuth granules, iron granules, baryt or tungsten granules or a mixture of at least two of these materials.
• the polymer is a binder and preferably epoxy or silicone.
• the metal powder and / or the metal granules and / or the metal powder mixture and / or the metal powder / metal granule mixture and the binder are mixed together in a stirrer or mixer, wherein the mixing takes place at normal temperature.
• the shielding material according to the invention increases the safety of radiation protection through its properties. Other advantages of the shielding material are that it is flexible and corrosion resistant.
• the new shielding material is environmentally friendly as it has no toxic properties. It can therefore be produced without protective agents. It has good thermal stability.
• the shielding material according to the invention is easy to produce. By conventional shaping methods, for example casting methods, any objects and shapes can be produced from the shielding material according to the invention.
• the shielding material according to the invention can be produced on site without difficulty and processed and installed or assembled on site for the various desired products, articles and molds.
• Bismuth is the only heavy metal that is non-toxic. In nature it occurs mainly as bismuth luster (Bi 2 Ss) and as trioxide (Wismutocker Bi2 ⁇ 3 ). Commercially, bismuth is often obtained as a by-product in the production of anaereal metals, such as copper, lead and tin. Compared with other materials, bismuth has an extremely good capture cross-section with respect to both .beta. And .gamma. Rays, so that bismuth exhibits good shielding properties compared to other heavy metals.
• Iron is the heavy metal that is most common among all heavy metals in the earth's crust. Due to its high affinity for oxygen, it is not present in elemental form in the earth's crust, but above all in the form of oxides, carbonates and sulfates. Iron powder can be made by atomizing liquid metal via a nozzle. It can also be produced from iron oxide by gaseous reducing agents. In addition, iron powder can be obtained by thermal decomposition.
• Barite also known as barite or barium sulphate (BaSO 4 ), is a commonly occurring mineral from the mineral class of anhydrous sulphates with no foreign anions. It is formed from hydrothermal solutions or sedimentary, sometimes with the participation of biological processes. Submarine sediment deposits have been formed by mixing ascending barium-rich hydrothermal solutions with sulphate-containing seawater. This type of deposit can contain billions to billions of tons of barytes. One example of this is the Meggen camp in Germany. Barite is added to the well drilling, due to the high specific gravity of 4.3 - 4.7 g / cm 3 . Furthermore, baryte is used for the production of white pigments and photographic paper. It is also part of heavy concrete as well as of contrast agents in X-ray examinations.
• Tungsten is a white-glossy, high-density heavy metal that is brittle in its pure state. Its density is 19.25 g / cm 3 . Tungsten is not found in nature in dignified form. There are some minerals, especially oxides and tungstates known. Tungsten can not be obtained by reduction by coal from the oxide ores, since this tungsten carbide is formed. Tungsten is added to the ammonia solution to form a complex called ammonium paratungstate (APD). This complex is filtered off and then converted at 600 ° C into relatively pure tungsten trioxide. Annealing gives tungsten (VI) oxide (WO 3 ), which is reduced to steel-gray tungsten at 800 ° C. under a hydrogen atmosphere.
• VIP ammonium paratungstate
• Tungsten has the highest melting point and the second highest boiling point of all pure metals. Its best known use is therefore as a filament in incandescent lamps.
• Tungsten is a white glossy, high-density (19.25 g / cm 3 ), hard (Brinell hardness of 250 HB) and strength (tensile strength of 4200 N / mm 2 ) brittle high tensile strength (19.25 g / cm 3 )
• Tungsten is a very chemically resistant material Metal, which itself is hardly attacked even by hydrofluoric acid and aqua regia, at least at room temperature. The most important application is because of its high melting point in the lighting industry as incandescent filament in incandescent lamps and electrode in gas discharge lamps and electron tubes.With its high density, it is used for balance weights and Abschir Although its density, and thus the shielding effect, is much higher than that of lead, it is less commonly used as lead for the purpose because it is more expensive and harder to work with, according to the current state of knowledge, tungsten and its use as Physiologically harmless, tungsten does not show any carcinogenic effects.
• Epoxy resins are produced by condensation of epichlorohydrin and bisphenol.
• Epoxy resins form liquid to viscous, glassy substances. Depending on the degree of crosslinking with corresponding hardeners, such as polyamines results in a liquid to solid product. The adhesion to metals is extremely good and the resulting product is extremely resistant to environmental influences, including corrosion. Solid epoxy resins show no irritating effects, no toxic and no carcinogenic properties - even in prolonged occupational exposure.
• Silicone is a polymer material polysiloxane, a material based on silicon and oxygen with organic substituents and has physi- kalische properties, which is well suited for the production of flexible shielding products, such as shielding aprons.
• the material is known by the trade name of "silicone", where there are a variety of different types of silicones.
• polysiloxanes are hydrophobic materials that, unlike other elastomers, have good chemical stability to water, acids and alkalis, the main advantage of using polysiloxanes This is because they can be easily adapted to the particular application and can be easily achieved by adding additives or modifiers, and polysiloxanes are made from environmentally friendly materials that can be easily disposed of after use without conditions.
• the shielding material according to the invention can be cast in various forms, which can be adapted to the respective application. It can be used for isotope needles, glove boxes, electron accelerators, radon generators, in isotope production and other applications. It can be used in the form of wall and system components, as plates, mortar plaster or material for containers, shielding containers, pipe sheathings and foils. The production of the various products is carried out at normal temperature, with the required components in an agitator or mixer mixed together and then in the appropriate
• the density of the metal powder polymer shielding materials can be adjusted, with a density of 6.0 g / cm 3 for bismuth powder-epoxy mixture, for iron powder-epoxy mixture a density of 4.1 g / cm 3 and For baryta powder-epoxy mixture, a density of 2.8 g / cm 3 can be achieved.
• Mco- 60 integral attenuation coefficient for 1.25 MeV
• Figure 4 shows the arrangement of the measuring points on the sample plates of bismuth powder-epoxy mixture and iron powder-epoxy mixture.
• test plates had a diameter of 150 mm and a wall thickness of 30 mm and were divided into 55 fields as shown in FIG. For each of the 55 fields, the attenuation was measured with the ⁇ -radiation. For each field, two measurements were made so that the homogeneity of a 110-measurement plate was determined.
• Epoxy plates and iron powder epoxy plates again. Both figures show the density inhomogeneity; it was determined by the determination of the mean attenuation factor 1 / I 0 and the local deviation from this mean value. The attenuation of the v radiation was determined with a mean energy line E y 1.25 MeV.
• the density inhomogeneity was determined by the indication of the deviation from the mean value of the attenuation factor l / lo- By a double measurement of each individual measuring point, the measurement error could be adjusted to a value of cst. 4% be reduced. Significant deviations from the mean density inhomogeneity can be observed at the marginal points. However, this is not due to the inhomogeneity of the sample plate, but is largely due to scattering of the y radiation in the edge region of the sample plates.
• the investigations revealed a production-related density of only 8% for bismuth powder epoxy boards as well as for iron powder epoxy boards. This result means that with a double / puffy syrup of bismuth as well as of ice & n the polymer (epoxide) forms a tight bond without voids.
• the metal powder and / or metal granulate / polymer mixture according to the invention is capable of being cast-on and can therefore be very flexible and differentiated. be used.
• the shielding material according to the invention has substantially better corrosion resistance than the conventional shielding materials steel and lead by the coating of the metal powder and / or the metal granules by the polymer (binder epoxy resin or silicone).
• the disadvantage is at best the relatively high price, for example, for bismuth powder or bismuth granules, so that this material may not be economical for large and heavy shielding transport containers. However, there are applications for smaller, lighter components, as described below.
• Polymer shielding material and the iron powder or the iron granulate P ⁇ tymer shielding Materia! can be cast into handy stones, such as dovetail profile bricks, so that the bricks can be built into shielding walls or flexible shields.
• the previously common pencils can by
• flexible shields of bismuth powder polymer and / or bismuth granulate polymer stones and / or iron powder and / or egg granules polymer stones and / or from barite powder polymer and / or Baryt granules polymer stones and / or tungsten powder and / or tungsten granules polymer stones are used. Even with dismantling of technical equipment such flexible and quickly changeable shields would be advantageous.
• shielding containers for isotopes with ß and y radiation for research purposes, for hospitals, for measuring equipment and many other applications on the market.
• These shielding containers are usually made of lead and must be transported by motor vehicle. They are unwieldy and heavy due to lead shielding.
• the Abschirrnmaterials invention in particular the erfindu ⁇ gsdorfen bismuth powder and / or bismuth granular epoxy material and / or the Wolframpulver- and / or tungsten granulate epoxy material as material for containers they can easily with the same shielding about 10% - be ter.
• Weight of silfkon mixture material and / or granulated-epoxy resin mixture material or bismuth granulate-silicone mixture material and / or tungsten granulate-epoxy resin and / or tungsten granulate-silicone mixture material can be saved.
• metal granules instead of metal powder as the shielding material alone or in combination with one or more of the metal powders described above has the advantage that the specific gravity of the shielding material is increased. As a result, a higher radiation shielding is achieved with the same thickness of the Ablematerials or material can be saved at the same Abschirrn Ober.
• a thinner shielding wall can be used. For example, the thickness of a shielding wall can be reduced from 4 cm to 3 cm while maintaining a good Abschirrn moral.

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• Chemical & Material Sciences (AREA)
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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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• 2008
  • 2008-02-09 DE DE102008008379A patent/DE102008008379A1/de not_active Ceased
• 2009
  • 2009-01-23 AT AT09708264T patent/ATE515039T1/de active
  • 2009-01-23 EP EP09708264A patent/EP2240940B1/fr active Active
  • 2009-01-23 WO PCT/DE2009/000095 patent/WO2009097833A1/fr not_active Ceased

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