FR2505080A1 - Partition protective against pollutants and radiation - with layers of compsn. contg. boracic prods. and highly hydrogenated plastics - Google Patents

Abstract

A compsn. which forms a protective and anti-fission partition comprises several layers of material contg. boracic prods. and strongly hydrogenated plastics. The partition gives protection to man against the widest range of physical, chemical and biological pollutants, including radioactive dust. The partition gives anti-neutron protection to men in ground, sea or air vehicles. Reinforced concrete contg. boracic materials, partic. at least 3 wt.% of colemanite, is the pref. layer impermeable to mechanical penetration, and to alpha-, beta-, gamma-, and X-rays, and gives some protection against penetration by neutrons. A semi-rigid layer may be applied on 1 or both faces of a concrete or metal partition, or may be interposed within the partition; this layer consists of several sub-layers of differing mechanical strength, some being of highly hydrogenated polystyrene and others of highly hydrogenated polyethylene, with a high content of elements of low atomic number giving protection against radiation. Pref., the semi-rigid layer contains at least 40 wt.% of polyethylene and 5% of polystyrene.

Description

THIS INVENTION HAS THE OBJECT:
A new association of materials whose particularity is to be able to constitute a protection for the man against all pollutants or aggressive physical, chemical and biological, in the broadest sense.

This association of materials meets characteristics which make it, in particular, a wall whose sealing is protected from cracks due, for example, to earthquakes. There are two very different types of physical, chemical and biological dangers, from which humans must remain isolated: - pollutants which do not cross a continuous physical barrier on a molecular scale - chemical, bacteriological and dust pollutants ... and the aggressive, having the capacity to cross, without destroying them, continuous barriers: radiation, whether particulate or not. In conventional protection, these two types of protection are dissociated.

The present invention relates to a new protective association, with a view to creating multi-protection walls. Protection against pollutants or aggressive chemical or bacteriological, is obtained by the establishment of a wall whose tightness is total vis-à-vis all the particles, as small as they are. This protection is also effective against any contamination by radioactive dust, of which, apart from the radiation problems discussed below, the main thing is the mechanical resistance of the wall.

Reinforced concrete constitutes the most suitable solution for this layer, prepared according to the prior art, enriched with boracic materials and the reinforcements of which have an orientation such that they cannot serve as a preferred line of passage for neutrons, and this , by a positioning such that these metallic reinforcements are as perpendicular as possible to the presumed trajectory of an incident neutron flux.

The thickness of the concrete will be calculated according to the degree of protection sought and the site chosen.

Protection against aggressive wave-like properties is generally resolved by the multilayer structure of the wall.

The physical and mechanical characteristics of the concrete, boracic, on the one hand, and polyethylene-polystyrene layers, on the other hand, make this wall an effective radiation shield, whatever the frequency of this or these, and so, @@@ seit @ear nature, provided that @@ ux-ci s @@@ nt de c @@ r @@@ @@@ ée (of the order of a few seconds ).

@some examples are given to clarify the above: - during heat radiation: stop by the layer of bet @ n,
resistance to several thousand degrees, - during a shock wave: thickness of reinforced concrete resistant to
several tonnes per m2 of surface, - safety greatly increased by the semi-rigid layer
playing an anti-cracking role.

"ALPHA" RADIATION:
It is a little penetrating radiation, therefore stopped by the first millimeters of the wall. Protection is especially useful against contamination, - sealing -.

"BETA" RADIATION: @rotection also widely established by the concrete layer. The gamma radiation emitted by braking is also stopped by the concrete layer, even for high energy BETA particles.

"GAMMA" RADIATION:
High density bodies have the best attenuation factor. The sufficiently dense concrete layer is an effective anti-gamma screen.

"X" RADIATION:
The attenuation of the "X" rays passing through the material is all the more important as the average atomic number of this one is high.

The concrete, still here, is considered, in ancient art, as an effective and economical protection.

CASE OF NEUTRONS:
Against neutrons, the most efficient bodies are those with a low atomic number. The anti-crack underlay, made of polyethylene and polystyrene, highly hydrogenated, very powerfully attenuates any neutron flux. In addition, the enrichment of concrete with boracic materials increases this protection, both with regard to thermal neutron fluxes and with regard to fast neutrons. The stresses, due to the scha @ f- @ement by absorption of the radiation, are controlled by the reinforcements placed in the concrete and the under-layer. In order to show the interesting properties of the new combination of materials according to the invention, tests have been requested, intended to test the protection against radiation of the least known in the art and the most dangerous including neutron radiation (@ ssai of the NATIONAL ESSAY LABORATORY @ RARIS).

Claims (6)

1) composition constituting a protective and anti wall  cracks comprising several layers of material,  with added boracics and materials  highly hydrogenated plastics. 2) Composition according to claim 1, characterized by  the fact that at least one of the products is colemanite,  associated by mixing or applying to the protective wall. 3) Composition according to claims 1 and 2 and character  additionally created by the presence on one, both sides  or inserted in the wall, concrete or metallic,  a semi-rigid layer itself made up of several  underlays of different mechanical strengths, of which  the density of elements with a low atomic number is important  aunt. 4) Composition according to Claims 1, 2 and 3 and charac  terrified by the fact that the semi-rigid layer is made up  killed by underlayers, at least one of which contains  polyethylene and other highly hydro polystyrene  Genoa. 5) Composition according to Claims 1, 2, 3 and 4 and charac  terrified by the fact that the concrete layer contains at least  3% by weight of colemanite and the semi-rigid layer at least  40% of its weight in polyethylene and 5% in polystyrene. 6) Composition derived from the principle of claims 1, 2,  3, 4 and 5 allowing by application of a plastic layer  semi-rigid treated, external, internal or intercalated, the  anti-neutron protection for people inside  vehicles on land, at sea and in the air.