Patent Number: 055457967
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1 of the drawings, one embodiment of a contaminated waste storage container 10, made solely of contaminated metal, is shown. This container has no interior or exterior concrete support or shielding associated with it. The metal for the container is made by melting radioactive rods, tubing, metal nuclear components and the like in a metal melting furnace as described in detail later in this specification. In the furnace, the bottom, lower-grade radioactive melt is separated from a top higher-grade radioactive slag phase. This bottom molten metal is cast into a container form including an associated lid, and cooled. The metal melting process involves expensive, regulated equipment, and so containers made by this process should serve special disposal needs of utilizing radioactive feed metal having at least a 130 Bq/g activity. This container could be used and transported under a variety of circumstances, but would be particularly advantageous where melting, casting the container, filling with contaminated waste material and burial or storage would be in the same site, so that feed metal having as high as or over 370 Bq/g activity can be used, saving tremendous storage or burial volume for very "hot" metal. FIG. 2 shows one embodiment of a structure or article such as slab wall 2 which can be made of radioactive waste, hazardous waste, or their mixtures. Since this structure may not necessarily be used to directly contain contaminate material, when contaminated metal is used alone in this embodiment, the contaminated metal should not be diluted or alloyed with virgin filler or the like to the point that the contaminated metal constitutes less than 35 weight % of the structure. In this instance, metal slag residue from a metal melter, for example, can be used to make such a slab walls 2, bricks, panels, blocks, sheets, slabs, grids, floors, liners, impact, limiters or the like, as described in detail previously. This structure could also, for example, have a contaminated or non-contaminated, particulate, plastic or rubber matrix containing radioactive concrete, metal, or slag, or a contaminated metal mat matrix filled with plastic. FIG. 3 shows another embodiment of the invention, where a storage module 10 is a container having walls and lid substantially or completely of plastic. Useful plastic or plastic resins include, for example, rubber compounds, polypropylene, polycarbonate, polyester, polyvinylidene fluoride, polyvinyl acetate, polyvinyl chloride, epoxy resins, phenolic resins and, preferably, polyethylene which contains a large number of hydrogen atoms per cm.sup.3, mixtures and copolymers thereof, and the like, all of which are well known plastics or plastic resins. When the plastic is thermosetting (will degrade rather than melt upon heating) to get good bonding, the plastic should be uncontaminated. This is usually not as important when thermoplastic resins are used since they can be remelted after initial use. Epoxy and phenolic resins are examples of thermosetting resins. When plastic is used as the binder material making up the container walls, hazardous solids in the form of, for example, soil, and "toxic" chemicals such as polychlorinated biphenyls, petroleum hydrocarbons, pentachlorophenols (PCB's, PHC's and PCP's respectively) and the like, can be included. This module can enclose a high integrity container as shown. While not shown in FIG. 3, the plastic container can contain contaminated metal fibers in discrete form distributed throughout the walls, bottom and lid and/or contaminated metal mesh or contaminated metal mat. The contaminated metal fibers that can be used in discrete form will have the same ranges as those set forth later in this specification for concrete containers. The contaminated metal mesh or mat can be from 60% to 95% porous (5% to 40% of theoretical density). When a metal mesh or mat is used in the plastic container it will provide a metal, open matrix, readily completely impregnated by liquid plastic resinous materials. The wall thickness of the plastic container shown in FIG. 3.can range from 0.5 cm (0.2 inch) to about 7.6 cm (3 inches), and the metal mesh or mat can constitute from 10% to 100% of the final wall thickness, that is, if the plastic container wall is 5 cm thick, the central metal mesh or mat skeleton or matrix can be from 0.5 cm to 5 cm thick. Preferably, however, metal fiber will not penetrate through the exterior wall surface. In processing, the mesh or mat could be placed in a mold and flowable, liquid plastic resin could be injected or poured into the mold to completely impregnate the open, porous mesh or mat; and then the plastic/mesh or that combination can be heated under pressure to cure the plastic resin and cause it to fill all voids, and consolidate the container walls. The plastic can comprise two copolymerizable components or a single plastic resin, all with appropriate diluents, hardeners, flow control agents, catalysts, initiators, and other appropriate additives. Referring now to FIG. 4 of the drawings, one embodiment of a unitary structure such as storage module 10 is shown, which includes a container 12 formed of concrete or other suitable material, having a bottom and sidewalls. The container 12 is closed by lid 14 placed atop the upper most edges of the container. The lid 14 is attached to the container by way of ridge 13 on container 12 and a recess 15 on the lid 14. For the sake of facilitating a stacking relationship of the storage modules 10 in adjacent columns, the storage modules 10 can be shaped as hexagonal prisms, as shown in FIG. 4. Each of the sides of the hexagon is illustrated as a substantially flat side 16, and between each of the sides 16 is corner side 18. When the storage modules 10 are stacked, the sides 16 of adjacent modules 10 abut one another, to define a honeycomb-type arrangement when viewed as a plan view from above. Forklift grooves 22 are shown at the bottom of the module. In all instances, the containers described here and previously can be used as multipurpose containers for processing, transport, storage and/or burial, and can be transported from the manufacturing site of the container to the waste site, loaded with contaminated waste, and transported to a burial site for burial or storage. Also, processing such as solidification, dewatering, and the like, can be carried out in the container before it is sealed. Within the container 12 in FIG. 4, the sidewalls 16 and 18 define an interior space 20, which is preferably cylindrical. Within the interior space 20, several stacks of steel drums 26 are illustrated. These drums can contain radioactive or hazardous waste in liquid, solid or compressed form. Here, the module walls do not directly contact the waste. In this invention, the container and lid walls 24 also contain processed radioactive, hazardous, or mixed waste material intermixed as discrete fibers, particles, or the like with concrete and other additives. A void space, created in the cylindrical interior space 20 between the waste containers or packages 26 and sides of the container 12, can be filled with a contaminated or noncontaminated granular fill material 36, such as a cementitious grout. FIG. 5 of the drawings shows one embodiment of a square or round contaminated waste storage container made of concrete or other suitable material having sides 16 and lid 14, with or without a bottom. The sides and top can be set into place by means of lugs 30 and held in place by bolts 32. This module can enclose a high integrity container 34. The container and lid walls 24 in this invention will contain processed radioactive, hazardous or mixed waste material as described previously. A plastic liner is shown as 35. FIG. 6 shows an idealized, enlarged crosssection of an example of the walls 24 of some of the containment systems previously described. As shown, a particulate sand filler 36, shown as medium sized open circles, and cement 38, shown as medium sized shaded circles, form a matrix 42 which would make up most of the body of the wall 24. Interdispersed in the matrix material 24 could be fine flyash particles shown as 40, radioactive metal fibers 44 and/or radioactive, ground, large concrete aggregate or other hazardous material 46 shown as hatched large sized open circles, and virgin, ground, large aggregate shown as large sized open circles 50. While not shown, cut pieces of contaminated plastic material may also be included within the matrix. Unlike the use of fibers or aggregate in a containment structure wall made of totally virgin, uncontaminated materials, it is preferred that the radioactive materials used herein be in a non-agglomerate form and do not clump to create a fiber-aggregate volume 48 of high radioactivity; or at least such agglomerates must be minimized. The radioactive fibers, radioactive concrete, and hazardous solid waste should be uniformly and homogeneously dispersed throughout the matrix 42 so that they are essentially discrete fibers and particles separated and encapsulated by the matrix material. In the case of a plastic sheet or plastic particulate matrix, without use of metal fibers or metal mat, the contaminated particulates 46 or fibers 44 would be dispersed between encapsulating plastic particulates or connected chains or polymers. As can be seen in FIG. 6, the largest particles are aggregate particles 46 and 50 and the next largest particles are cement 38 and sand or other filler 36. The cement particles 38 along with the sand or other filler particles 36 form a matrix containing all the other materials. The flyash particles 40, if used, would be the next smallest, and together with the very small, shaded, silica fume particles 52, if used, would provide a series of different sized particles to provide substantially complete interior void volume filling, providing an essentially void free, low porosity article. As described previously, small metal fiber material such as stainless steel can also be used in the structure. Also, spherical and amorphous particles can be used in place of or with the metal fibers 44 shown. It may also be desirable to include uncontaminated carbon, ceramic, plastic or fiberglass fibers as additional reinforcement. In order to accomplish such a radioactive dispersion in the matrix, the radioactive fibers, concrete particles and hazardous waste solids should meet important size and profile parameters and must be added in a certain sequence to the composition mixture. FIG. 7 shows one embodiment of the method of this invention, which will here be described in substantial detail for use of an uncontaminated sand and cement matrix and radioactive metal and radioactive concrete additives, as an example, although the method of this invention is not at all so limited, and the article can include metal alone, metal with hazardous or mixed waste, or a variety of metal or plastic binders such as steel, polyethylene resin, plastic with a metal mat matrix, and the like, as pointed out in detail previously. FIG. 7 shows two Flow Paths for treatment of radioactive additive. Flow Path I relates to radioactive metal treatment and Flow Path II relates to radioactive concrete treatment. In Flow Path I, radioactive metal, such as stainless steel tubes used in cooling nuclear reactors, piping used on nuclear sites, metal spent fuel channel boxes, centrifuges, compressors and motors used for uranium enrichment, siding used on nuclear reactor site buildings, other stainless steel, nickel, iron, lead, chromium, technetium or other radioactive metal components used in or near nuclear reactors, or the like can be the radioactive starting material. In most cases the metal radioactive starting material will be inspected, and segregated according to metal type, for example, a run of all stainless steel may be made separate from a run of all carbon steel, based on the desired end product to provide a radioactive metal feed (A). All manner of configurations can be used, although in most instances the metal feed will be cut to a convenient size for further treatment, with, for example, shears, acetylene torch, or if necessary an underwater plasma torch, or the like. The radioactive metal feed will then be transported to a metal melter, such as an induction furnace operating at a temperature over about 1,200.degree. C., which will be described later in the Examples. In the metal melting furnace, a purified, lower grade radioactive, all metal bottom phase is formed, and separated from an impure, higher grade radioactive metal slag top phase. Up to 15 weight % uncontaminated metal as additive, preferably only up to 10 weight % uncontaminated metal, such as nickel, chromium, or the like, may, in some cases, be added and reacted in the furnace where it may be necessary to provide a bottom phase metal composition having special strength characteristics necessary to cast fibers or other articles or structures. The all metal bottom phase can be used for further processing into metal fibers, or can be cast directly into a variety of articles, such as blocks, slabs, walls, containers, and the like by means of path 53. Generally, if the slag phase is not separated, any metal fibers produced would not have the physical properties required to provide high tensile strength to the concrete matrix into which they are added, or the metal articles or structures, such as slabs, would not have the required composition for the embodiment needed. However, in rare instances, where very pure radioactive metal feed is used, a top slag phase may not form. Step (B) in FIG. 7 can produce spun metal fibers from the molten metal or cast metal ingots. Such melt spinning of fibers is well known in the art, and further details on such a melt casting process can be found in U.S. Pat. Nos. 4,930,565 (Hackman et al.) and 4,907,641 (Gaspar). While the top phase slag can be poured into molds to make highly radioactive shield block ingots by means of path 53', a portion of the slag could also be quenched by water to form generally spherical particles or agglomerates of amorphous shaped metal which can be used separately as filler via path 54, or added to the sand as shown in FIG. 7. The size and width or diameter of included metal bars, fibers, generally spherical particles and amorphous particles affects tensile strength and compressire strength of the containment system in which they are used. Radioactive or non-radioactive, cast, reinforcing bars, when used, can have substantial lengths, preferably, of from about 25 cm to about 50 cm and diameters of from about 0.10 cm to about 3 cm. The radioactive metal fibers should have lengths of from about 0.5 cm to about 20 cm, preferably from about 1.0 cm to about 3.5 cm and have a length:width (length to width) aspect ratio of between 200:1 and 20:1, preferably between 150:1 and 75:1. Therefore, if the fiber length is 10 cm, the width or diameter can range from 0.05 cm to o.5 cm. Fibers of non-conforming geometry are sent back through the metal melt and fiber casting process. The most preferred fibers are stainless steel fibers having a chromium content of from 15% to 26% and a nickel content of from 8% to 14%. When used in concrete the preferred weight range of the metal fibers is from about 2% to about 55%, most preferably from 2 weight % to 30 weight %. The generally spherical metal particles can have diameters from about 0.001 mm to about 30 mm and the amorphous metal particles can have a thickness of from about 0.01 mm to about 30 mm. If the fibers are below 0.5 cm in length, they would have no advantageous effect on the tensile strength of the concrete. If the fibers are over 20 cm in length, they will clump and deform, and will not have the desired effect on the tensile strength of the concrete. The metal will be free of any oil residue through the melt casting and prudent handling and storage. In the Flow Path Row II concrete processing steps, large sections or slabs of radioactive concrete or large size radioactive gravel are provided in step (A). The concrete may be wall sections, chunks, slabs, and dust, resulting from demolition of or around nuclear reactor structures, or it can be used waste containers which have acquired low level radioactivity, and the like. The concrete can be pulverized to provide generally spherical particles having diameters (rough diameters) from about 0.001 mm to about 30 mm in step (B). Road gravel which has become radioactive over the years from vehicles or the like traveling over nuclear site roads using such gravel can also be used, as well as gravel from filtration ponds or the like. This gravel if of large size can also be ground. Its final size should be in the same range as the pulverized concrete. If the particles are below 0.001 mm diameter, it may be detrimental to the strength characteristics of the concrete. If the particles are over 30 mm diameter, it would be difficult to form containers and the like, particularly those having thin walls. Preferably, the radioactive gravel or concrete particles are not of one size but are distributed substantially equally between 0.001 mm and 30 mm diameter. A variety of particle sizes are required in the embodiment of the method of this invention, the largest being the radioactive concrete aggregate or radioactive road gravel and any virgin aggregate used, the next finest being the filler and virgin sand used with the Portland cement, followed by fine flyash and ultra-fine silica fume, as described later; which all interact to provide high density and low permeability by having small particles within a larger particle matrix and eliminating most void volume. Radioactive concrete dust could be used in association with the uncontaminated sand as shown by path 52 in FIG. 7. Preferably, all the radioactive concrete material will be reduced in size by crushing or grinding to provide a "fresh", wettable surface. As mentioned previously, uncontaminated river "pea" gravel or man-made virgin aggregate can be used in addition to the radioactive concrete particles. The uncontaminated aggregate will have the same rough diameter particle size range of about 0.001 mm to 30 cm as the radioactive concrete particles. Based on the amount of radioactive concrete particles to be used, the amount of virgin gravel can be determined so as to provide a useful, dry concrete mix, approximating weight ratios of (aggregate):(sand):(cement):(water) of (10):(5 to 7):(3 to 4):(1 to 2). The particle size of the sand, which can be river sand or finely ground rock or aggregate and which acts as filler should be in the rough diameter particle size range of from about 0.015 mm to about 10 mm, a range below the aggregate size. Amorphous radioactive metal slag particles resulting from water quenching of slag, as shown in FIG. 6 can be used as filler in substitution for part of the sand as long as it is round if needed to fit into the sand particle size range, that is, a thickness of from about 0.015 mm to about 10 mm. As previously mentioned, any very fine radioactive concrete dust in the sand particle size range can be added with the sand in making the initial cement mixture, but its weight amount will be determined by the limits on weight % radioactive concrete allowed to be added. Portland cement will be used in an amount determined by the above (aggregate):(sand):(cement):(water) ratio. The Portland cement is uncontaminated and is preferably a low heat of hydration cement, that produces a minimum of heat during cure, and which requires less water than standard cement. Such cement is commercially available and generally designated as moderate to low hydration Type IV, or low hydration Type IV. It is preferred to limit the amount of water used in the concrete mixture, supplementing the need for water for workability with plasticizer materials. The water used, can be regular, uncontaminated water, or water that is radioactive. If the water is radioactive it can be processed by filtration to remove organic impurities to provide a stabilized liquid. Plasticizers are used with concrete to increase the plasticity of the concrete mixture for extended periods of time. Useful plasticizers are commercially available under the tradename RHEOBUILD (manufactured by Master Builders Co.). These plasticizers are commonly salts, such as calcium or sodium, of beta-naphthalene sulfonate polymers or other hybrid mixtures in compliance with ASTM C-494. For the purpose of this invention, the plasticizer is added not only to reduce water content but to increase the workability of the concrete mix and its flowability and extend the possible mixing time such that thorough mixing of all components will occur. The plasticizer must be added to the concrete mixture in the final stages after the aggregate, sand, cement, and other chemical additives have been introduced into the "dry" mix and initial slump tests are taken. Use of the plasticizer prior to initial slump testing can lead to erroneous water-cement ratio calculations. The amount of water used in this invention is in accordance with the weight ratio previously described, and such that the consistency of the concrete mixture will have a 3 cm to 7 cm slump after addition of sand and water and prior to addition of plasticizer, where the term "slump" means the amount of contraction of the top of a cone of concrete upon cure and is a term standard in the art, defined in ASTM C-143, and where no subsidence is O slump. Use of minimal water provides a desirable, relatively dry consistency cement mixture. Subsequent addition of plasticizer will increase the slump level and flowability or plasticity of the concrete. Radioactive water, such as that resulting from quenching slag as shown in FIG. 7 can be fed by path 56 to replace some or all of the water used in the concrete mixture. Other components that are added to the concrete mixture, as shown in FIG. 6, are flyash 40 and silica fume 50. Flyash is the very fine ash produced by combustion of powdered coal with forced draft, and often carried off with the fuel gases from such processes. A baghouse filter or electrostatic precipitator is necessary for effective :recovery. Considerable percentages of CaO, MgO, silica and alumina are present in the flyash. The particle size of the flyash is preferably from about 0.001 mm to about 0.01 mm. This provides particles finer than sand and larger particles than silica fume. Silica fume, or fumed silica, is a colloidal form of silica, SiO.sub.2, made by combustion of silicon tetrachloride in hydrogen-oxygen furnaces. It is a fine white powder, and for the purposes of this invention will have a particle size range from about 0.00015 mm to about 0.0015 mm, providing ultra-fine particles which are extremely important in adding strength and increasing the density of the cured containment system, so that it has a low permeability eliminating leakage possibilities. The preferred range of these components is about 0.2 to about 2 parts by weight of silica fume, and about 0.5 to about 4 parts by weight of flyash, based on 100 parts of binder material, where from about 0.1 to about 1 part by weight of chemical plasticizer, based on 100 parts of binder material is added with the processed, radioactive material, based on mix workability requirements. Other additives can also be used, for example air entrainer materials, which, when added in a small effective amount, causes microscopic air bubbles in the cured containment system upon cure. These microscopic air bubbles provide an insulative effect and increase freeze/thaw resistance to cracking. Another useful additive is a hardener which also allows reduction of water content and improves workability and finish. Although virtually any circumstance is possible, clean, uncontaminated cement will be used when it is a binder; and thermoplastic resins, such as epoxy resins will always be clean and uncontaminated when used as a binder, as mentioned previously, to insure good bonding. After the concrete mixture is thoroughly mixed and at a consistency of about a 3 to 7 cm slump, the plasticizer and radioactive metal, are slowly added, preferably, over a 10 minute to 20 minute period, at a stir-mixing rate, preferably, of approximately 30 rpm to 50 rpm, for batches of 900 to 2,700 kg. The resulting form of the cast composition can be any of those shown in the drawings, for example, the container structure of FIGS. 4 and 5, or the wall or barrier structure of FIG. 2, and the like. These structures can have a liner coating, or layer, 35, as shown, for example in FIG. 5, on the inside or outside, such as a plastic resin, water barrier coating, metallized coatings, and the like, to serve a variety of purposes including preventing stirred liquids from leaking out or exterior water or liquids from leaking in. Plastic or plastic resins, described previously, for example polyethylene, polyvinylidene fluoride, polypropylene and polyvinylchloride, are particularly advantageous for inner and/or outer plate or sheet coverings of the exterior of the container or as closely conforming interior liners, having thicknesses of from about 0.2 cm to about 2.5 cm. These liners and exterior covers can add substantially to fracture resistant properties as well as containment and leak proof properties. These plastic resin liners and exterior covers can be conveniently used in concrete fabrication of containers as inner and outer forms for the concrete. These liners and exterior covers, preferably, are closely attached to the concrete, most preferably by means of anchor means, integral to the liner or cover, which are embedded in the concrete. For example, liner or cover ribs, dovetails or T portions and the like, extending from the liner or cover into the concrete to anchor, connect and interlock the plastic resin and the concrete upon the concrete setting are advantageous, as described in U.S. Ser. No. 07/758,220, filed on Sep. 12, 1991 by the assignee of this invention, entitled "Storage Module For Nuclear Waste With Improved Liner" (Meess W. E. 55,126-C2). The liner or cover can also be simply molded or injected to close fit, and possibly impregnate the surface of the concrete, creating a bond with the concrete container, or can be glued in place by a suitable, high strength, water resistant adhesive. In the case of making a plastic container such as shown in FIG. 3, the following general steps would be taken. First, contaminated plastic drums, bags or the like are cut to an appropriate size so that they can be melted to form a fluid, pourable mass. Then the hazardous fluid mass would be, generally, centrifugally cast, as is well known in the art. This casting can be used in conjunction with the metal fibers or metal mesh or metal mat as previously described. The following examples further illustrate the invention, and should not be considered limiting in any way. EXAMPLE 1 Contaminated waste structures, in the form of blocks, were made utilizing a licensed, pilot, metal melter induction furnace from cooled, cast, melted, radioactive metal tubing waste. The all-metal blocks had a specific activity over about 130 Bq/g and had no support. The blocks were substantially free of slag residue. Blocks of this type would be useful for shielding material. A transportable, multipurpose container similar to that shown in FIG. 1 could also easily be cast from such radioactive metal tubing waste. EXAMPLE 2 Two small box forms were made to provide cast concrete containers having outside dimensions of 406 mm wide.times.406 mm long.times.355 mm high, with an internal right circular cylinder cavity measuring 300 mm in diameter by 300 mm high. The forms were coated with an organic release material to aid in stripping once the concrete was poured. The forms were also coated with sealant at the joints to prevent concrete bleed. These forms were then filled with a radioactive concrete mixture, resulting in containers with 50 mm thick walls and bottom to which a separate lid was formed having a minimum thickness of 50 mm and outside dimensions of 40.6 cm.times.40.6 cm to match the container which was 40.6 cm.times.40.6 cm. The completed modules provided stackable modules providing a minimum of 50 mm of concrete between the internal cavity and the environment. The container is the same as shown in FIG. 8 as 80, with top 81 and cavity 82 for waste material. While this container sacrificed packaging efficiency with thickening of walls at the diagonal corners, its fabrication was considered acceptable for a prototype. The concrete mix for both containers contained highly radioactive metal slag agglomerates, contaminated fibers, contaminated concrete aggregate and contaminated water, where both samples also contained uncontaminated aggregate, sand, cement, and flyash. Radioactive slag was obtained from the Westinghouse Electric Corporation, Scientific Ecology Group (SEG), metal melt facility at Oak Ridge, Tenn. The slag material was analyzed at the SEG laboratory facilities using a Tennelec Model CPVDS30-29195 for a SOLO CUP Analysis. The highest levels of activity were found to be from Cesium 137, Cobalt 60, and Uranium 235 and 238, and the total activity was found to be 7750.8870 disintegrations per minute per gram (dpm/g). A substantial amount of this was to be used in the container. Contaminated clean-up water resulting from daily SEG cask maintenance and cleaning operations was obtained for use as the concrete mix water and contaminating liquid. The water used was analyzed at the SEG laboratory facilities. The analysis of the clean-up water shows an actively level resulting primarily from one radionuclide, Cobalt 60, and the total activity was found to be 0.222 dpm/g. Crushed recycled concrete was obtained for this project by demolishing a portion of the lid of an earlier manufactured concrete container. The concrete was crushed by hand into pellet sizes no larger than 19 mm in diameter. The recycled concrete was washed in the above described contaminated water for fine partial removal and therefore is deemed to have the same radiological properties, resulting primarily from Cobalt 60. Stainless steel reinforcing fibers were obtained. These fibers are commercially available under the trade name MelTEC Stainless Steel Fibers. The stainless steel fibers were rinsed in the above described contaminated water to aid in the adherence of the stainless steel fibers to the cement. Due to the use of contaminated water the stainless steel fibers are considered to have the same radiological characteristics, resulting primarily from Cobalt 60. The fibers were all approximately 15 mm to 16 mm in length. While the water, crushed concrete and steel fibers were not strictly radioactive as defined previously, they did have activity levels above natural activity levels and were certainly tainted with radioactive elements and were contaminated. Clean limestone based aggregate material conforming to AASHTO number 67 stone gradation and properties was obtained. Clean river sand conforming to AASHTO requirements for concrete sand was also obtained. This sand material as well as the clean limestone based aggregate are generally the same as that used in making normal precast concrete. Type 1 Portland Cement was obtained. The cement was as commercially available for sale for all construction activities. Standard concrete quality fly ash was also obtained from the SEG solidification operations. A summary of the materials used in both containers is shown below in Table 1: TABLE 1 ______________________________________ PARTS BY PARTICLE MATERIAL WT WT % SIZE (mm) ______________________________________ Cement 60 14.8 0.0015-0.01 Sand 110 27.1 0.1-1.0 Aggregate 140 34.6 0.1-10 Contaminated 15 2.7 15.87 Stainless Fibers Contaminated 25 6.2 0.1-20 Fractured Concrete Radioactive Slag 25 6.2 1-30 Contaminated Water 30 7.4 ______________________________________ Prior to any mixing or handling of materials, all workers were dressed in protective clothing and had passed the SEG Radiation Workers Safety Course. In addition to written instructions oral directions were also given for the mixing of the concrete batch. The composition steps were as follows, where all components were added by weight measurements in the following order with complete mixing: 1) Aggregate 2) Radioactive Slag 3) Contaminated Fractured Concrete 4) Sand 5) Cement 6) Contaminated Water 7) Contaminated 15.87 mm (5/8 inch) Stainless Steel Fibers 8) Plasticizers (0.2 wt. %) The mixing procedure was to first add the aggregate (including slag and recycled concrete), sand, cement and water, mixing thoroughly as the ingredients were added. The water was added at a rate to maintain an approximate four inch slump according to ASTM standards. Once the concrete mix was completed, the steel fibers were added slowly to the mix ensuring even distribution. Care was taken to add water to maintain a workable slump of at least 4 inches. With the concrete thoroughly mixed and all ingredients added in proper proportions the concrete was ready for pouring. The concrete was thoroughly mixed, ensuring even distribution of all materials including radioactive constituents. The concrete was introduced to the forms by hand and rolled into its final position. The two containers were cured for 2 days in the forms under plastic sheeting. The freshly poured containers were sprayed with a service water mist and wrapped in plastic and allowed to mist cure according to ASTM standard specifications for three days. After three days of curing the containers were unwrapped and the wood and plastic forms removed. All residual material resulting from the forming process was cleaned from the containers using hand tools. The completed containers were inspected and then sprayed with a water mist, repackaged and allowed to cure for the remaining 25 days to reach full design strength. Following the 28 day curing period the containers were removed from their wrapping and cosmetic repairs for surface blemishes and minor honeycombing, caused by form bleed, were completed. The tops were fitted to the containers and they were then surveyed by SEG Health Physics personnel for radiological activity. The results of all the testings on the containers is shown in Table 2 below: TABLE 2 ______________________________________ Sample Containers 1 and 2 Radioactivity Levels ______________________________________ Water 3.76 .times. 10.sup.-7 .mu.Ci/ml* = 0.222 dpm/g Fibers 3.76 .times. 10.sup.-7 .mu.Ci/ml* = 0.222 dpm/g Fractured Concrete 3.76 .times. 10.sup.-7 .mu.Ci/ml* = 0.222 dpm/g Slag 7.75 .times. 10.sup.3 dpm/gr** = 2.5 .times. 10.sup.-3 .mu.Ci/ml ______________________________________ *0.0139 Bq/g **129.5 Bq/g The use of 6.2 wt % highly radioactive slag provided substantial radioactive material content in the containers. Final density of the concrete containers was over 90% of theoretical. Similar results would be achieved with commercial sized containers, for example, containers having internal dimensions of 182 cm length.times.122 cm width and 122 cm height, with a lid weighing 318 kg and a container weight of 1,730 kg; able to contain up to about 1375 kg of contaminated material within the container structure itself and an internal payload of about 2,270 kg of contaminated material. Thus, utilization of this invention could increase total contaminated payload by about 60% compared to a container made of uncontaminated material. The two sample concrete containers were then delivered for use as waste process, transport, storage and disposal containers at the SEG facility. The small size and uniqueness of the prototypes limited the uses of the containers. Sample container 1 was lined with a polypropelene liner similar to material commercially available for material transport buckets. The exterior surfaces of container 1 were coated with a commercially available concrete penetrant and sealer. With the liner tightly in place and the coating dried, radiological waste material from the SEG facility was placed in the container. The lid of the container was sealed and the outside of the container was surveyed for surface activity. A level of activity below that of background was found and recorded. The container was then transported for temporary storage at the SEG facility. Sample container 2 was not lined or coated as was Sample container 1. Instead, Sample container 2 had a standard, radioactive waste container placed inside the body of the sample container. The standard container held waste material deposited and processed to SEG standards. The material in the sample container was then wrapped, sealed and the lid placed on the sample container. The entire sample container was then surveyed for surface activity and was found to be below 0.5 milirem. This sealed sample container was then permanently sealed, packaged and legally transported by SEG from Oak Ridge, Tenn. to a waste disposal site in Barnwell, S.C. As can be seen contaminated materials can be used, or reused, in a wide variety of articles, many of which are, or can be, applied to purposes in which they are again, or further, contaminated.