MXPA00006528A - Nuclear resistance cell and methods for making same - Google Patents

Nuclear resistance cell and methods for making same

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Publication number
MXPA00006528A
MXPA00006528A MXPA/A/2000/006528A MXPA00006528A MXPA00006528A MX PA00006528 A MXPA00006528 A MX PA00006528A MX PA00006528 A MXPA00006528 A MX PA00006528A MX PA00006528 A MXPA00006528 A MX PA00006528A
Authority
MX
Mexico
Prior art keywords
group
materials
barium
radiation
lead
Prior art date
Application number
MXPA/A/2000/006528A
Other languages
Spanish (es)
Inventor
Joseph Adrian
Original Assignee
Nurescell Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nurescell Inc filed Critical Nurescell Inc
Publication of MXPA00006528A publication Critical patent/MXPA00006528A/en

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Abstract

The present invention is a shielding material that resists both nuclear radiation and high temperatures and is especially suited to encasing radioactive waster materials to immobilize them. The material is a mixture comprised of two or more organic polymers in which included fillers are cross-linked within the phenylic side chains of the polymers and copolymers. Other fillers provide radioactive shielding and may be merely included within the cross-linked matrix. The material contains a tough matrix with embedded particles of radiation shielding substances and thermoconductive materials with an overall ceramic-like or ceramometallic properties. The material is thermosetting and can present an extremely hard material -e.g., 20,000 p.s.i. shear strength. The material is comprised of a mixture of vulcanized rubber and/or rubber-like polymers, various radiation shielding inclusions, polyimide resin and phenolformaldehyde resin. After being mixed in the proper proportions the material sets up at an elevated temperature (e.g., 260°C). The final material has a density of between 8 and 50 pounds per cubic foot depending on the proportionand identity of the radiation resistant inclusions.

Description

CELL FOR NUCLEAR RESISTANCE AND METHODS FOR MANUFACTURE DESCRIPTION OF THE INVENTION The present invention relates to the field of material and compositions for covering and containing radioactive substances and radioactive substances in particular. For some years, especially after the nearby "smelting" of the reactor at the Chernobyl Energy Station, there has been considerable international antipathy or rightist hostility to nuclear power. This despite the demonstrated and increasing damage of the global climate change that results from the atmospheric effects of burning fossil fuels. The main opposition to nuclear power bases from the probably irreparable dangers and environmental damage that result from the long-lived radioactive waste produced by the current nuclear reactors. Even the potential environmental damage of nuclear waste must be somewhat balanced against some environmental damage from the continuous use of fossil fuels. It seems clear that the only way to avoid the environmental catastrophe posed by global warming - soon to return to the pre-industrial economy - is to replace conventional energy sources with one based on nuclear fission. At some future date, "dirty" fission energy sources may be replaced with clean fusion-based systems, but at this time nuclear fission seems to be just one option. Since there is currently no knowledge in any way to eliminate nuclear waste, our goal must be the safe management and disposal of this waste. The current nuclear fuel cycle presents a number of operations that are potentially environmentally adverse. These include the mining and manufacturing of nuclear fuels, the fission of these fuels and the hazards presented by operating reactors, the on-site storage of spent fuel, the transportation and recycling or disposal of these fuels. It seems that safe reactors are within the reach of human engineering. The real environmental problem is possessed by the recycling and disposal of spent nuclear fuels. Whether spent fuel is reprocessed to produce additional fissile material (the most efficient alternative from the point of view of long-term energy needs) or if the spent fuel is simply disposed of directly, there is a considerable volume of highly radioactive substances that must be isolated from the environment. The currently acceptable procedure is the concealment of radioactive material in deep geological formations where they can decay to a level - less dangerous without any human intervention. Ideally, these "buried" wastes should remain environmentally isolated without human monitoring or supervision. Any alteration of human civilization can lead to a catastrophic outflow of radioactive materials. That is, one simply throws the waste into a hole. These materials are constantly generating heat as well as potentially explosive gases, mainly hydrogen. Emitted radiation alters and thin most materials. Currently the best procedure is to reduce waste to eliminate solvents. The reduced waste is then vitrified or otherwise converted into a stable form to avoid environmental migration. However, the important task of producing special materials that exhibit unusual resistance to the radiation, heat and chemical conditions that generally accompany radioactive waste remains. Ideally, such materials have radiation shielding properties and can be used to protect and cover otherwise reduced waste. Another important application of such materials is the sealing of decommissioned or damaged nuclear facilities. The simplest and unpurified of such materials is probably concrete. Due to mineral inclusions in simple Portland cement-based materials or similar materials to which additional shielding materials (eg heavy metal particles) these substances provide nuclear radiation shielding. Nevertheless, simple concrete may not survive much under the severe chemical conditions provided by some nuclear waste. Liquid nuclear waste concrete tanks have useful lifetimes of less than fifty years. Concrete is more effective against reduced vitrified waste but is still far from the ideal. There have been a number of experiments with novel shielding container materials that can be more readily applicable and have superior physical and / or shielding properties. However, until now these materials have not proven to be widely successful. The present invention is a shielding material that resists both nuclear radiation and high temperatures and is especially suitable for covering radioactive waste materials to immobilize them. The material is a blend comprised of two or more organic polymers in which fillers included are crosslinked within the phenyl side chains of the polymers and copolymers. Other fillers provide radioactive shielding and can be included simply within the reticulated matrix. The material contains a rough matrix with embedded particles of radiation shielding substances and thermally conductive materials with properties similar to ceramic totlaes or ceramometalicas. The material is thermofixed and can present an extremely hard material - for example, 20,000 p.s.i. of shear stress. The material is comprised of a mixture of vulcanized rubber and / or rubber-like polymers, various inclusions of radiation shielding, polyimide resin and phenol-formaldehyde resin. After being mixed in the appropriate proportions the material sets at an elevated temperature (260 ° C). The final material has a density of between 8 and 50 pounds per cubic foot depending on the proportion and identity of the radiation resistant inclusions. The objects and characteristics of the present invention, which are believed to be novel, are indicated with particularity in the appended claims. The present invention, as well as its organization and manner of operation, together with additional objects and advantages, can be understood by reference to the following description, taken in connection with the accompanying drawings. Figure 1 represents a diagrammatic representation of the structure of the nuclear resistance material of the present invention. Figure 2 is a chemical diagram of the imidized and aromatic polyimide which is believed to comprise the polymeric backbone of the material of the present invention. The following description is provided to enable any person in the art to make and use the invention and indicates the best modes contemplated by the inventor to carry out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the general principles of the present invention have been defined herein specifically to provide a nuclear shielding material that is easy to apply and withstand a variety of challenges. chemical and physical The present invention provides a novel material for shielding and interning radioactive waste having superior shielding and physical properties for concrete. The material is non-cellular in that it contains a rough matrix with embedded particles of radiation shielding substances and thermally conductive surfaces with ceramic-like properties. This pseudo-ceramic or ceramic structure reduces the total weight of the material while currently adding its favorable physical properties. Since the material is proposed to give nuclear resistance it is referred to herein as NRC (nuclear resistance cell material). The CRN is comprised of two or more organic polymers in which included fillers are crosslinked within the femly side chains of the polymers and copolymers. Other fillers provide radioactive shielding and can be included simply within the crosslinked matrix. The CRN is thermofixed and once completely pulverized it can present an extremely hard material (approximately Rockwell R, _92-20,000 p.s.i. shear resistance) that is watertight to a wide range of chemical agents. Prolonged exposure to a very high temperature (2,200 ° C) can ultimately result in the decomposition of the organic matrix. However, the various fillers and inclusions then form a ceramic-like matrix such that the total properties of the CRN remain relatively constant. That is, its shielding capacity is not significantly affected and the ceramic structure maintains significant physical resistance even when exposed to very high temperatures. CRN is produced by mixing and heating approximately equal amounts by weight of compound 1 with compound 2. Each of the compounds contains a portion of the cross-linking and shielding system of the final material. The basic thermosetting resin system employed comprises vulcanized clophed rubber (caoutchouc), polyamide ream and phenol formaldehyde. Various radiation shielding materials and others are included to impart favorable resistance and radiation properties. It is conceived herein that these various ingredients are represented by four different group component materials denoted by the letters "A", "B", "C", and "D". There are a number of alternative ingredients in each group Component as explained later. Compound 1 is composed of Component materials of group A and C wherein the Component materials of group C are preferably present in between 7.5 and 17.5% by weight of the material of the component of Group A. Compound 2 comprises a mixture of materials of the component of Group B and D where the weight of the material of the component of Group B does not exceed the weight of the materials of the component of Group A in Compound 1 and where the materials of the component of Group D comprise between 0.5 and 7.5% by weight of the materials of the Group B component in the same Compound 2. A wide range of compositions for Compound 1 and Compound 2 are clearly possible while following the following guidelines wherein a compound 1 given in composition is coupled to a compound 2 given. The Group A component comprises an elastomer portion of the matrix. An isoprenoid number containing rubber-like compounds can act as the materials of the Group A Component. The favored material is a semi-synthetic vulcanized and chlorinated polymer. That is, the carbon atoms that make up the polymer chain covalently bound bonded sulfur and chlorine atoms together. Other halogen substituents are also applicable. Commercially available compounds of this class include butyl rubber, and polymers available under the brand names of NEOPRENE®, THIOKOL®, KRATON®, and CHLOROPRENT, among others. Similar similar rubber-like polymers also usable as members of the Group A Component are well known to those skilled in the art. The CRN materials produced to date generally contain only a single material from the Group A Compound, but there is no reason why a mixture of several of these materials can not be used to obtain particular properties. For example, the use of several more highly halogenated materials increases the total resistance to certain chemicals, particularly organic solvents. An application in which the CRN is reliable to be exposed to organic solvents may benefit from the use of more heavily halogenated Group A Component materials. The Group B Component materials comprise any number of polyimide or polyimide resins containing imide polymer bonds of the general structure -CO-NR-CO wherein "C" denotes a carbon atom, "O" denotes an atom of Oxygen, "N" denotes a nitrogen atom and "R" denotes an organic radical. The possibilities for "R" is almost endless, but readily obtainable polumoid resins employ R groups such as met? l-2-p? rrol? dona. Resins available that are Group B Component materials include materials sold under the trademarks named P-84Q and ENVEXT. In addition, some or all of the material of the Group B Component may comprise a v-polydimethyl ether resin. Group C Component materials are added mainly to increase the shielding to nuclear radiation and CRN resistance. Many Group C Component materials are barium compounds and / or compounds of elements in the same group of the periodic table as barium. For both non-nuclear and nuclear applications, one or more of the following powders, which should be of the average particle size of no more than about 10 μm in diameter and preferably less than about 5 μm in diameter, are useful: aluminum oxide ( about 5-15% by weight of the material of the Component of Group A used in the particular Compound 1 and preferably about 10% by weight); barium compounds (up to about 35% maximum by weight) such as barium sulfate (BaS04), barium carbonate (BaC03), barium ferpt (BaFe? 20? 9), barium nitrate (Ba (N03) 2), barium metaborate (BaB204, H20), barium oxide (BaO), barium silicate (BaS? 03), barium zirconate (BaZr0), barium acrylate, barium methacrylate, barium alkoxide, barium isopropoxide, and / or barium ironisopropoxide; lead compounds (up to about 35% maximum by weight of the Group A Component material) such as lead (II) carbonate ((PbC03) 2 .Pb (OH) 2), lead (II) chromate (PbCr04), lead molybdenum oxide (PbMo04), lead (II) nitrate (Pb (N03) 2), lead orthophosphate (Pb3 (P04) 2), lead (II) oxide (PbO), lead oxide (II, III) (Pb30), lead stearate (II) (Pb (C? 8H3502) 2), lead acrylate, and / or lead methacrylate, particularly for nuclear applications, tungsten carbide powders, titanium carbide, Lead, heavy metal compounds, and iodine-including iodides and organo-duro compounds-can also be added, but the total weight of these five additional materials should preferably not exceed more than about 10% by weight of the Group A Component material. On the other hand, the total amount of all the powders listed above should comprise approximately 7.5-17.5% by weight of the Compon material Group A entity; for nuclear applications the total amount of all the preceding materials of the Component of Group C is preferably approximately 12.5-17.5% by weight of the material of the Component of Group A. The materials of the component of Group D consist of two different subgroups. The polymeric materials of the Group D component provide the thermofixing properties to the CRN. These materials are proposed to react with and crosslink the materials of the Component of Group A and B. The polymecop material of the Group D Component "archetype" is a res of phenolformaldehyde (up to about 5% by weight of the Component Group B material). ). A wide range of the phenol-formaldehyde reams are available and are useful in the present invention. In addition, formaldehyde (preferably as paraformaldehyde) can be added directly. In this case the phenolic reams can be added favorably instead of the phenol-formaldehyde resin (that material which is formed in situ). Alternatively, the additional radiation resistance can be obtained by replacing the plat ovmilo polymer (organoplatm) for the polyformaldehyde compounds. Any of the phenol-formaldehyde and / or plat ovmilo polymers are essential parts for the CRN composition. Some of the other materials that can be used as the additive materials of the Group D Component. Such additives for polyformaldehyde or plat ovmilo include silica gel smoked and acacia gum (which acts as a binder). The additive materials of the Group D Component may also include: magnesium oxide (approximately 1-8% and preferably approximately 3% by weight of the total of the Group D Component materials); zirconium oxide (approximately 1-5% and preferably approximately 2% of the total materials of the Group D Component); silicon dioxide (approximately 1-10% and preferably approximately 5% of the total materials of the Group D Component); silicon oxide (approximately 1-5% of the total materials of the Group D Component); zirconium silicate (approximately 2-10% and preferably approximately 4% of the total materials of the Group D Component); and carbon. In addition iron oxide and / or other iron compounds such as iron phosphate (FeP02), iron suicide (FeSi); and / or iron sulfate (III) (Fe (S04) 3) can be used but should not represent more than 2% of the total weight of the Group D Component material. Zirconium oxide, zirconium silicate, and iron oxide are preferably used for nuclear applications only. Titanium oxide (up to about 1% maximum weight of Group D Component materials) and beryllium oxide (up to about 1% maximum weight of Group D Compound materials) can also be used. Although the CRN made without additives to the formaldehyde resin, the CRN is generally less effective than the CRN made with the formaldehyde resin. However, CRN is contemplated herein without additives for the formaldehyde resin. While the Group C Component materials described in the preceding paragraphs are the preferred CRN ingredients, some of them may be omitted and that the total weight of the Group C Component materials used may be less than 7.5% by weight. Group A Component materials. For example, it is contemplated here to use only aluminum oxide, and formaldehyde to create CRN designed to reduce weight and increase thermal conductivity. In addition, the barium compounds listed above, the lead compounds listed above, iron phosphate, iron silicide and / or iron sulfate can also be used for nucleation reduction. The CRN made with iron oxide, titanium oxide, zirconium silicate, zirconium oxide and beryllium oxide can be used in all applications, but is preferably used in nuclear contaminated areas. The CRN containing free carbon is not used preferably in nuclear applications due to the danger of fire especially in the presence of free oxygen. However, CRN made with free carbon can be used in non-nuclear applications because it is lightweight and not expensive; it also acts as a fire retardant, although carbon monoxide results when the CRN containing free carbon is burned. The CRN is created by mixing together two basic compounds "1" and "2" comprised of Component materials from Group A, B, C and D, where material B is a polyimide or polyimide resin (equal to up to 100% by weight of material A). Compound 2 comprises various combinations of phenolic / thermoset polymer and / or platinomovinyl. CRN is created by mixing and heating components 1 and 2, together. Compound 1 = [material component of Group A + material component of Group C (7.5-17.5% by weight of A)] Compound 2 = [material component of Group B (does not exceed the material weight of the component of Group A) + ( material component of Group D (0.5-7.5% by weight of the material component of Group B)] CRN = Component 1 '+ Component 2 Compound 1 is comprised of material from the Group A component premixed with the material from the Group C component such that the material C is 7.5-17.5% by weight of the material A. The compound 2 is comprised of the material of the component of Group B premixed with the material of the component of the Group D, such that the material D is 1-15. % by weight of the material B. Alternatively, the compound 2 can be made by mixing the platinomovinyl polymer together (approximately 1-15% by weight of the Compound 2) instead of the polyformaldehyde, in the material of the component of Group B. The two premixed compounds are then mixed together, so that the original weights of material A and material B before premixing are preferably equal to each other. It is also contemplated herein that the material of the Group B component may comprise a ream of platinum phenyl, and / or ream of platinum vmilo. Using a phenolic platinum resin for the Group B Component material will produce a denser version of CRN. The denser version is preferable for nuclear environmental applications, while the less dense version of CRN is preferable for non-nuclear environmental applications. The mixing together of the two compounds should preferably take place in a static mixer at high pressure (at least about 2400 p.s.i.). Alternatively, the mixing can be done by hand, or with a standard mixer, or with an ultrasonic mixer, or with a static mixer attached to an ultrasound device. However, an ultrasonic mixer is more practical. The compound 1 is injected through an ultrasonic mixer rotating nozzle, and the compound 2 is injected through another rotating nozzle. The two combined compounds are combined in the middle of the bucket-like head at the end of the mixer, and the resulting mixture is injected into a mold, preferably made of aluminum, or sprayed on a surface, where the CRN begins to cure and polymerize . For nuclear applications, the CRN should be formulated with an increase in weight / volume of approximately 30-60% and preferably by approximately 50% compared with non-nuclear applications. The CRN mixed then cured at an elevated temperature (approximately 260 ° C for approximately 45 minutes). In addition, if Compound 1 is heated to 120 ° C just before it is mixed with compound 2, the resulting CRN can cure in only about 25 minutes. The CRN has a density in the range of about 8 to 50 pounds per cubic foot and when cured at a high temperature and pressure it has an extremely hard, solid structure with a shear strength of 20,000 p.s.i. Figure 1 represents a diagrammatic representation of the interaction of the various materials of the Group Component in cured CRN. The material of the Component of Group A is bound to the phenol formaldehyde resin binder of the Group D Component material and this link includes the various binders / additives of the Group D Component. At the same time, both Group A Component materials and Group D components are crosslinked to the imide polymers of the Group B Component material. This fully crosslinked structure also includes the nucleation blockers of the Group C Component. It is believed that the polymer structure of the main structure formed by thermal curing is an imidized and aromatic composition shown in Figure 2 with R which is, in a preferred composition, methyl-2-pyrrolidone. Ceramometallic properties are provided by the various additives and tend to reinforce and predominate when and if the material is subjected to extremely high temperatures. In addition to the equivalents of the claimed elements, obvious substitutions known now or later are defined for one of ordinary skill in the art to be within the scope of the defined elements. The claims are understood in this way to include what is specifically illustrated and described above, what is conceptually equivalent, what is obviously substituted and also that essentially incorporates the essential idea of the invention. Those skilled in the art will appreciate that the various adaptations and modifications of the preferred embodiment just described can be configured without departing from the scope and spirit of the invention. The illustrated embodiment has been indicated only for the purposes of example and should not be taken as limiting the invention. Therefore, it is understood that, within the scope of the appended claims, the invention may be practiced differently as specifically described herein.

Claims (7)

  1. CLAIMS 1. A radiation-resistant thermosetting composition characterized in that it comprises: a heat-cured mixture of a first composition and a second composition, wherein the first composition comprises a mixture of the materials of group A and materials of group C of such The materials of group C comprise 5-20% by weight of the materials of group A wherein the materials of group A comprise elastomeric compounds containing isoprenoids and wherein the group C materials comprise shielding compounds for nuclear radiation; and wherein the second composition comprises a mixture of group B materials and polymeric materials of group D such that the materials of group D comprise 0.5-10% by weight of the materials of group B wherein the materials of group B comprise at least one of the polyimide resin, polyimide resin, phenolic platinum resin and platinum vinyl resin and do not exceed the weight of the group A materials in the first composition and wherein the group D materials comprise phenol formaldehyde resin .
  2. 2. The radiation-resistant thermosetting composition according to claim 1, characterized in that the materials of group C are selected from the list consisting of barium sulfate, barium carbonate, barium ferrite, barium nitrate, metaborate barium, barium oxide, barium silicate, barium zirconate, barium acrylate, barium alkoxide, barium isopropoxide, barium ironisopropoxide, lead carbonate, lead chromate, molybdenum oxide and lead, lead nitrate, orthophosphate lead, lead oxide, lead stearate, lead acrylate, and lead methacrylate, tungsten carbide, titanium carbide, and iodine.
  3. 3. The radiation-resistant thermosetting composition according to claim 1, characterized in that the group D polimepcos materials also comprise platinum and vmilo polymer.
  4. 4. The radiation-resistant thermosetting composition according to claim 1, characterized in that the group D polymere materials also comprise additives of group D.
  5. 5. The radiation-resistant thermosetting composition according to claim 4, characterized because the group D additives are selected from the group consisting of silica gel, acacia gum, magnesium oxide, zirconium oxide, silicon dioxide, silicon oxide, zirconium silicate, carbon, iron oxide, phosphate iron, iron silicide, iron sulphate, titanium oxide and beryllium oxide.
  6. 6. The radiation-resistant thermosetting composition according to claim 1, characterized in that the weights of the first composition and the second composition are selected in such a way that the weight of the materials of group A in the first composition is equal to one weight of the materials of group B in the second composition.
  7. 7. The radiation-resistant thermosetting composition according to claim 1, characterized in that the group B materials comprise platinum phenolic resin and / or vinyl and platinum resin.
MXPA/A/2000/006528A 1998-11-06 2000-06-30 Nuclear resistance cell and methods for making same MXPA00006528A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US09187641 1998-11-06

Publications (1)

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MXPA00006528A true MXPA00006528A (en) 2001-12-04

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