DE4119989C2 - Radiation protection mat for the shielding of radioactive radiation - Google Patents

Description

The present invention relates to a radiation protection mat for the shielding of radioactive radiation, which in essence union of a carrier layer, a shield intermediate layer and a topcoat.

More recently, especially through the increased environment Consciousness, it seems necessary ge both on heap poured radiation-emitting ore wastes For example, incurred in the uranium ore extraction, as well naturally occurring radioactive radiation emitting Ge stone surfaces or other underground floors at least in the Areas accessible to the public shield that the radiation exposure and the wind and Water erosion kept at the lowest possible value can be.

Such a shield could be achieved, for example the fact that one uses the heap or the one in question Covering rock surfaces with a layer of material, which in able to completely, or at least, the radioactive radiation partially absorb. After covering with Ma of course, it should be ensured that the Material layer obtained in the applied layer thickness remains, including a loosely applied bed or else a cover with a lead foil probably not suitable he Seems to migrate as the loose bulk and the relative tear thin and not just tear-resistant lead foils the.

DE-OS 37 04 503 are sealing mats known for landfill purposes, consisting of two layers of a nonwoven fabric and a layer of swellable clay interposed therebetween exist, and all three layers are needled together.

Another double-layered plastic cover for landfills with arrangedbetween Betonitmehl is known from DE-OS 37 00 645th known.

From DE-AS 10 21 535, DE-AS 12 39 030, DE-OS 14 64 620 and DE-OS 31 37 853 are fabric with a shielding layer of a radioactive or ionizing Radiation or terrestrial radiation shielding or absorbing Material known. The fabrics are used for production of protective clothing, eg As aprons, or as blankets related.

Object of the present invention is therefore an Ab screen cover for radioactive radiation dumps, Rocky surfaces and other underground floors available too make, with a lasting and coherent Ab Screen cover is guaranteed, and preferably so is constructed that they simultaneously the wind and water radioactive dusts to a great extent or completely prevented.

This object is achieved according to the present invention through a radiation protection mat, characterized is that it consists essentially of a carrier layer, a Cover layer and a shield interlayer exists, wherein the carrier and / or cover layer of a nonwoven fabric and the intermediate layer of one radioactive radiation shielding or absorbing Ma material in the form of powder, shot, chips, fibers and / or Foil is made, and all three layers are needled together are.

The non-woven fabric Carrier or cover layer consists of a woven or knitted fabric or a Plastic film.

Preferably, the shielding or absorbing material consists of alkaline earth salts, lead salts, lead oxides, z. B. Mennige, lead powder, lead shot, lead wool, lead chips and / or lead foil. Of the alkaline earth salts barium sulfate is preferably used, in particular in the form of a heavy duty meal with a particle size range of 0.1 to 40 microns and a density of 4.0 to 4.25 g / cm ³ , as it is under the name Schwer spatmehl C14 in the trade is brought.

In certain applications, it has also been advantageous proven when the intermediate layer next to the actually shielding or absorbing materials in addition Contains bentonite. This can be particularly advantageous be, if at the same time one widge if possible would like to achieve watertight coverage.

Of course, the intermediate layer may consist only of a lead foil, or contain such an additional. Lead foils which are suitable are, for example, those which have a thickness of about 0.1 mm to about 0.2 mm and thus basis weights of about 1100 g / m ² to about 2200 g / m ² . The layer thickness of the shielding intermediate layer depends on the one hand on the radiation to be shielded and on the other hand on which layer thickness can be needled between carrier and cover layer depending on the carrier and cover materials used.

Of course it is in later practical use possible, the radiation protection mats according to the invention depending on Radiation intensity double or multiple superimposed lie apply.

The technique, with the carrier, intermediate and top layer with Needed each other is basically for a long time known.

For example, from the already mentioned above DE-OS 37 04 503 you mats known in which between two with each other needled nonwoven layers bentonite powder is needled. These sealing mats are preferably made of nonwoven fabric, in terms of both the carrier and the deck layer, on the other hand, but only the carrier layer made of a nonwoven fabric and the cover layer of a fabric or knitted fabric or a plastic sheet or the deck layer of a nonwoven fabric and the carrier layer of a Woven or knitted fabric or a plastic film.

The radiation protection mat according to the invention preferably has a cover layer that is actively needle-punched and off a non-woven fabric. A backing layer that is at least passively vernadelbar is ent, from the top layer ent held holding fibers against the cover layer. Between the cover layer and the carrier layer is a Interlayer shielding from the radioactive radiation or absorbent material, e.g. B. in powder and / or  Sheet form. The two layers are through this intermediate Layer needled through each other. The needling can according to a Nadelver known in needle felting technology drive done. When used This technology is most commonly felted for needling needles with triangular needle shank and lateral, against the Tip used to targeted barbs. common are also other forms, such as fork needles or loop needles. Also let the suture needles mentioned in the aforementioned book corresponding to the needling of the composite body use. The felting needles capture when plunging into the Fiber layer single or tuft of fibers from this Fiber layer and intertwine with the backing layer. The fiber layer must be actively needle-able for this purpose, d. H. It should fibers out of this layer erfas sen, with a portion of these fibers still in the Fiber layer remains anchored.

The nonwoven fabrics used are preferably made of qua plastic-plastic fibers, in particular of polyethylene, Polypropylene, polyester, polyacrylic and / or polyamidefa fibers. Particularly preferred for the present application are high density polyethylene (HDPE) or nonwovens Polypropylene, which is rotproof (resistant) against all in Soil-occurring substances are and thus demonstrable ensure an extremely long service life. Yours truly high tear strength causes a substantial insensitivity against mechanical stress.

The structure is in the used th nonwovens preferably by mecha by needling nisch consolidated spun fiber web. They are structured  the crimped assembled fibers have a surface area Form with countless labyrinthine corridors. in this connection The soil structure is ideally replicated. The fabric of the Nonwovens can be coarser depending on the nature of the soil or fine tune, allowing for optimal adaptation The Anstählende soil is guaranteed. The mechanical Solidification guarantees a high coefficient of friction between the upcoming soil and the nonwoven fabric and the Ab cover. Instead of mechanically ver needled by needling Non-woven fabrics can also be used for such nonwovens put using the sewing technique or by Verwirbe mechanically consolidated or such nonwovens, which were chemically solidified.

The possibly additionally with the the radioactive ray ment shielding or absorbing materials Bentonites are clays with noticeable to high content smectite (montmorillonite), which has the properties (high Swellability, good water binding capacity, high plasticity) decisively determined. To get out of a little swell in water alkaline earth bentonite is a highly swelling active bento The alkaline earth ions of bentonites become nitrites by alkali ions, preferably sodium ions, replaced. When "highly swellable" active bentonite therefore becomes sodium bentonite with its greatly increased plasticity, viscosity, thixo tropie and water absorption preferred, which is such a part chenverteilung that the main amount or over weighing part of the particles has a particle size below 0.002 mm (2 microns). An example of this is a Bentonite B4, where more than 90% of the particles have a Particle size of less than 0.06 mm and more than about 70% the particles have a particle size of less than 0.002 mm respectively.  

In the preparation of the radiation protection according to the invention mats one proceeds in such a way that one on the carrier layer too next the layer from which the radioactive radiation from shielding or absorbing materials and then on top apply the top coat and then all three Layers needled in a needle chair.

By needling the three layers in the needle chair he keeping the desired firm mechanical cohesion the three layers of radiation protection mat, given if, in the presence of bentonite, swelling of Ben Tonits by moistening additionally a water-impermeable speed of the radiation protection mats according to the invention guaranteed.

Preferably, both the carrier and the deck exist layer of a nonwoven fabric. But it can also be a construction be desired, wherein the cover layer of a nonwoven fabric and the backing layer of a woven, knitted fabric or a plastic film consists. Likewise, the cover layer from a woven, knitted fabric or a plastic film and the carrier layer consist of a nonwoven fabric.

The plastic film used is like the nonwovens, woven and knitted fabrics, preferably made of synthetic resins, in particular polyethylenes, Polypropylene, polyester, polyacrylates and / or polyamides belong. For heavily loaded environment one sets mainly High density polyethylene.

According to another embodiment be Although both the carrier layer and the cover layer made of a nonwoven fabric, in addition, however, is located between carrier layer and the intermediate layer of the radioactive radiation shielding or absorbing Ma  terial a tissue and / or a plastic film and / or a fabric-reinforced plastic film, which also mitver needles are.

On the other hand, the support layer but also only from a ribbon fabric (textile raw material arbitrarily, preferably Po olefin) with a basis weight of not less than 150 g / m ² or only consist of a plastic film with a thickness of not less than 200 μ (passively needle-punched components).

The backing layer that passes through the needle chair at the needle plate comes to rest, can thus at be either for example

• 1. a needle-punched nonwoven fabric whose fiber raw material consists of synthetic fibers;
• 2. a ribbon fabric with basis weights of non-dressings ner than 150 g / m ² , the textile fiber raw material is preferably made of polyolefins before;
• 3. a film with a thickness of not less than 200 μ, which consists of a non-degradable plastic, preferably of a polyolefin, in particular a High density polyethylene (HDPE);
• 4. a combination of nonwoven fabric with ribbon and / or foil. (Example: needle punched nonwoven fabric of 250 g / m ² combined with ribbon cloth of not smaller than 60 g / m ² ); or
• 5. a combination of coarse and fine ver Needled nonwovens.

If one uses a carrier layer of nonwoven fabric and fabric and / or plastic Fo In this case, it is preferable to first needle both layers together during the mechanical consolidation of the web  fabric by needling. In a separate operation If you bring the interlayer, cover it with another nonwoven fabric layer as a cover layer and ver Needed again.

The intermediate layer from the radioactive radiation Shielding or absorbing material is essentially evenly. Depending on the application the thickness of this intermediate layer is preferably 0.5 up to 10 mm. However, it can also be smaller or larger, what both of the materials used as well as by the depends on the respective radiation intensity.

Is the intermediate layer z. B. from barytes of flour initially described type, so this is at least partially in or in both layers of nonwoven fabric embedded. For example, about 30 to about 50% of the barite flour used in the web or fleece material layers are located.

Usually, the thickness of the intermediate layer is smaller or substantially equal to the thickness of the nonwoven fabric layer or the sum of the nonwoven fabric layers when both the Carrier and the cover layer consists of nonwoven fabric.

A preferred embodiment of the radiation protection mat according to the present invention, one which fol has the following properties:

• a) Both the carrier layer and the cover layer be is made of a nonwoven fabric.
• b) The nonwoven fabrics have a basis weight of about 300 g / m ² (top layer) or from about 600 g / m ² to about 1000 g / m ² (carrier layer), a layer thickness of about 2 to 8 mm and are made of staple fibers with made a length section of about 60 to about 150 mm.
• c) The fibers of the nonwoven fabrics are made of polyethylene high density, polypropylene or polyester.

As already mentioned, the carrier layer can also consist of two previously needled nonwoven fabrics, the one Nonwoven fabric very fine pores and the other nonwoven rough Can have pores.

The preparation of the sealing mat is done preferably continuously. For example, one of Stock silo the shielding powder on the from a supply roll unwound carrier layer applied. In connection This is also handled by a supply roll Cover layer applied to the layer of shielding powder. The thus obtained three-layer Flächenge It is guided through a needle chair, in which all three Layers are needled in the usual way. Depending on Layer thickness of the intermediate layer of shielding powder and / or shielding film is the needled sheet, the representing the radiation protection mat, wound on roll or each cut to the desired length.

By the combination of features you get a particularly good fiber composite with the possibility of a excellent shear force transmission from a nonwoven fabric to the other, d. H. it can z. B. on a slope Shearing forces from the cover nonwoven through the shielding layer be transferred through in the carrier nonwoven fabric. In order to is according to the invention a fiber-reinforced, Mineral radiation protection mat with the possibility of a Shear force transmission on slopes, without the risk be is that by slipping the layers of the shield  layer is destroyed.

With the help of the radiation protection mat according to the invention thus given the opportunity to radioactively irradiated sub Soil and mining piles, z. In uranium ore mining areas, which must remain on site and are not disposed of can, with an effective surface protection against radio to provide active radiation, at the same time as he can be enough that

• a) the contained radioactive substances (gases, Parti kel) not with the infiltrating precipitation water mixed into the soil and into the groundwater can and
• b) the escape of the radioactive substance to the free Surface not only as radiation, but also as Dust is prevented or at least reduced.

The combined protection against the above-mentioned beam Depending on the individual case, the risk of oil and dust can arise from the combination

• a) a gas compensation layer for processing the strah gases (eg radon, krypton) and
• b) a surface covering with the invention Radiation protection mat.

The gas compensation layer consists of a suitable grain (eg gravel, sand) or similarly effective porous Materials in which the gases are collected analogously to landfill construction and selectively discharged and burned off if necessary. The gases themselves are subject to radioactive decay below Transmission of radioactive radiation.

The surface protection cover may vary depending on the individual case and if necessary, to cover previous modeling of the  the terrain (example of the Munich Trümmerberge) with a Drainage layer and a topsoil structure with greening after Built on the rules of landscaping and - if later Also required to be renewed or replaced.

In the following, the invention will be further described with reference to the examples le 1 to 4, but without limiting it. The abbreviations given in the examples have the following Meaning:

PES = Polyester PP = Polypropylene Bentonite B4 = see above description k _v -value = Permeability coefficient for water

example 1

For the preparation of this radiation protection mat are the following Starting materials used:

Backing layer:
two-layer nonwoven fabric and 800 g / m² PES / PP fibers
Top layer:
single-layer nonwoven made of 300 g / m² PES fibers
Shielding interlayer:
12 000 g / m² barite flour C 14 with a particle size distribution between 0.1 to 40 microns with a central value of 8 microns, ie 50% of Schwerspatmehles have a particle size of 0.1 to 8 microns and 50% of 8 to 40 microns, and a density of 4 g / cm³

The radiation protection mat obtained from these materials has following properties:

Basis weight (g / m²): about 13 100 Maximum tensile force (N / 10 cm) @ along: 1600 transverse: 2500 Elongation at maximum tensile force (%) @ along: 60 transverse: 50 Layer thickness (mm): 10

Example 2

For the preparation of this radiation protection mat, the following starting materials are used, wherein the submitted bentonite (2500 g / m ² ) of the heavy spar (1800 g / m ² ) sprinkles up and with a feed of 2.3 m / min and a piercing depth of 18 mm was driven at 190 strokes / min.

Backing layer:
Nonwoven fabric bandage made from 400 g / m² PP fibers
Top layer:
single-layer nonwoven made of 300 g / m² PP fibers
Shielding interlayer:
2500 g / m² Bentonite B4 (see description page 5, above) and 1800 g / m² barite flour C 14 (see example 1).

The radiation protection mat obtained from these materials has following properties:

Basis weight: about 5000 Maximum tensile force (N / 10 cm) @ along: 1400 transverse: 2400 Elongation at maximum tensile force (%) @ along: 60 transverse: 50 Layer thickness (mm): 8th k _v value (m / s): 1 × 10 ^-10 WD-test: no water leakage swelling after 1 week of storage in water, the layer thickness was 15.2 mm = 90%

Example 3

For the preparation of this sealing mat from the following starting materials are used, wherein the feed of the lead foil took place together with the carrier nonwoven fabric. feed:
2 m / min; Strokes: 180 / min; Penetration depth: 20 mm.

Backing layer:
two-layer nonwoven fabric and 800 g / m² PP fiber fabric
Top layer:
single-layer nonwoven made of 300 g / m² PP fibers
Shielding interlayer:
3800 g / m² bentonite B4 and lead foil with a thickness of 0.1 mm and a basis weight of approx. 1134 g / m²

The radiation protection mat obtained from these materials has following properties:

Basis weight (g / m²): about 6000 Maximum tensile force (N / 10 cm) @ along: 1600 transverse: 2500 Elongation at maximum tensile force (%) @ along: 60 transverse: 50 Layer thickness (mm): 13 k _v value (m / s): 1 × 10 ^-10

Example 4

For the preparation of this sealing mat are the following off used, wherein the feed of the lead foil took place together with the carrier nonwoven fabric. feed: 2 m / min; Strokes: 180 / min; Penetration depth: 20 mm.

Backing layer:
two-layer nonwoven fabric and 800 g / m² PP fiber fabric
Top layer:
single-layer nonwoven made of 300 g / m² PP fibers
Shielding interlayer:
8000 g / m² barite flour C 14 (see example 1) and lead foil with a thickness of 0.1 mm or a basis weight of about 1134 g / m²

The radiation protection mat obtained from these materials has following properties:

Basis weight (g / m²): 10 200 Maximum tensile force (N / 10 cm) @ along: 1600 transverse: 2500 Elongation at maximum tensile force (%) @ along: 60 transverse: 50 Layer thickness (mm): 9

Claims (11)

1. Radiation protection mat for permanent and coherent shield coverage of radioactive radiation emitting heaps, rock surfaces and other underground floors and optionally for the simultaneous prevention of wind and water erosion of radioactive dusts, characterized in that they are in wesent union of a carrier layer, a cover and a shield Intermediate layer, wherein the Trä ger- and / or cover layer of a nonwoven fabric and the shielding intermediate layer of a radioactive radiation shielding or absorbing material in the form of powder, shot, chips, fibers and / or film is made, and all three layers needled together. 2. Radiation protection mat according to claim 1, characterized marked records that the shielding or absorbing Ma from alkaline earth salts, lead salts, lead oxides (Mennige), lead powder, lead shot, lead fibers, lead wool, lead chips and / or lead foil. 3. Radiation protection mat according to claim 2, characterized in that the alkaline earth metal salt is a barium sulfate, preferably before a barite flour with a Korngrößenbe range of 0.1 to 40 microns and a density of 4.0 to 4.25 g / cm ² . 4. Radiation protection mat according to one or more of the An Claims 1 to 3, characterized in that the Zwi layer additionally contains bentonite. 5. Radiation protection mat according to one or more of the An Claims 1 to 3, characterized in that the Zwi layer only consists of a lead foil or one contains such lead foil in addition.   6. Radiation protection mat according to claim 4, characterized in that the lead foil is about 0.1 mm to 0.2 mm thick and has a basis weight of about 1100 g / m ² to about 1200 g / m ² . 7. Radiation protection mat according to one or more of the An Claims 1 to 6, characterized in that both the Carrier as well as the cover layer of nonwovens be stands. 8. Radiation protection mat according to one of claims 1 to 6, characterized in that either the carrier or the cover layer consists of a nonwoven fabric and the other of the two layers of a woven or knitted fabric or a plastic film. 9. Radiation protection mat according to one or more of the An Claims 1 to 8, characterized in that either the carrier layer or the cover layer of a nonwoven fabric (actively needle-able component) and the other layer a woven or knitted or an art fabric film (passively needle-able component) is, wherein all layers of non-degradable plastics Herge were presented. 10. Radiation protection mat according to one or more of the An Claims 1 to 9, characterized in that both the Carrier layer as well as the cover layer of a nonwoven fabric and in addition between carrier layer and the intermediate layer a woven, knitted fabric and / or a plastic film is located, which also mitverna delt is, with all layers of non-rotting Plastics are produced. 11. Radiation protection mat according to one or more of the An Claims 1 to 9, characterized in that the fleece materials are mechanically consolidated spun-fiber nonwovens and both the nonwovens and the fabrics, the knits and the plastic films of polyolefins, in particular made of polypropylene (PP) or high-density polyethylene (HDPE), or consist of polyesters (PES).