Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
  • G21F5/00—Transportable or portable shielded containers
  • G21F5/005—Containers for solid radioactive wastes, e.g. for ultimate disposal

Definitions

• the present invention relates to the field of long-lived radioactive waste storage. More specifically, the present invention relates to a container for storing radioactive waste of low to high activity and long life.
• Radioactive waste is any radioactive material that can no longer be recycled or reused by humans.
• Nuclear waste is of very different origins and natures. These are, for example, elements contained in the spent fuel of nuclear power plants, except Uranium and Plutonium contained therein, radioactive elements for medical or industrial use, or materials brought into contact with radioactive elements.
• Radioactivity reflects the toxicity of the waste including its potential impact on humans and the environment.
• Waste management is defined as follows: -Strong separation and transmutation of waste with the objective of sorting and transforming some long-lived waste into other, less toxic and shorter-lived waste. This way reduces the long-term harmfulness of waste.
• the long-term conditioning and storage processes on the surface or in the subsoil the objective of which is to develop radioactive waste packaging and their long-term storage methods, while guaranteeing the protection man and the environment with complementary solutions to those already existing, make it possible to further secure the waste.
• the radioactive period does not depend on the mass of material considered.
• Each pure radionuclide has a perfectly known period, its value can range from less than one thousandth of a second (eg Polonium 214: 0.16ms) to several billion years (eg Uranium 238: 4.5 billion years) going through all values Intermediates (Iodine 131: 5 days, Cesium 137: 30 years, Plutonium 239: 24,000 years, Uranium 235: 7 million years, etc.).
• a radionuclide is transformed, by disintegration, into another nucleus that is called "daughter product"; either this nucleus of filiation is stable, or it is also radioactive and disintegrates in turn ... and so on until a stable nucleus forms.
• An initial short-lived nucleus may very well have long-life filiation products. It is then the period of these that we retain.
• the classification following the activity reflects the technical precautions that it is necessary to take in terms of radiation protection; the ranking according to the period reflects the duration of the nuisance
• VL "long life”
• Radioisotopes will be all the more dangerous because they are highly radioactive, have chemical toxicity, and can easily pass into the environment.
• Radioactive waste that requires elaborate and specific protection measures are HAVL waste.
• the activity of this waste is usually sufficient to cause burns if you stay exposed too long.
• This waste HAVL are mainly from spent fuel nuclear power plants.
• HAVL waste storage in “basement” that is to say at depths, for example, not exceeding 5 m underground, and in monitored locations, provides access waste in the event of future recycling.
• Fire is a natural element eminently destructive, and HAVL waste storage means in the basement must be able to resist at least temporarily.
• WO 201 1/026976 discloses a package of radioactive waste comprising two layers covering the waste.
• the package comprises: an outer layer comprising a mixture of liquefied micronized plastics and a micronized iron oxide powder; an inner layer of vitrified materials.
• the outer layer is 2-3mm.
• the outer layer has an adsorbing power of the rays coming from the outside.
• the package may also include an additional plastic coating for protection against water.
• the outer layer is resistant to radiation and heat, but it certainly does not resist firing.
• Steel storage drums are also known and widespread on the market in various forms.
• the drums often used for long-term storage are the drums comprising a bottom, an outer wall and a lid, as well as means for closing the lid on the outer wall.
• An inner wall lead blocks some of the gamma radiation from the waste.
• Such drums do not withstand high temperatures.
• An object of the present invention is to increase the security of a radioactive waste container, more particularly to increase the resistance to high temperatures, for storage on the surface or in the basement and risk of fire associated.
• a radioactive waste container comprising a steel outer wall, a steel inner wall, a lead layer located between the two steel walls, a steel bottom, a cover of steel, a volume of quartz sand located inside the container, at least one inner container / cassette / box / encircled / covered at least partially by the volume of quartz sand and radioactive waste located inside the container.
• the container comprises, as the existing drums, an outer wall and a layer of lead. It is distinguished by a steel inner wall in contact on one side with the lead layer and on the other side with a layer of quartz sand, itself in contact with the wall of the container. Confining the lead in the space between the double wall steel ensures good radiation protection, even at temperatures above the melting point of lead.
• the quartz sand layer and the lead layer will enhance the resistance to high temperatures and will ensure the integrity of the container even at very high temperatures.
• the lead layer and the quartz sand layer will increase the temperature resistance and guarantee the integrity of the container even at very high temperatures for a period of time.
• Lead according to its purity has a melting temperature of about 320 ° C and a boiling temperature of about 1700 ° C.
• the quartz sands according to their purity have a melting temperature of 1300-1600 ° C and a boiling point of the order of 2000 ° C.
• the lead layer is of a thickness of between 25 mm and 50 mm.
• the layer of quartz sand between the container and the inner wall of steel preferably has a thickness of at least 2 cm, preferably at least 3 cm.
• the maximum thickness of the sand layer is preferably less than 10 cm, more preferably less than 8 cm and in particular less than 6 cm.
• the outer wall comprises a pressure relief valve.
• the valve will allow the evacuation of gases from the fusion / boiling of the lead contained in the space between the double wall of steel.
• the inner container is preferably made of stainless steel.
• the stainless steel inner container will not melt to a melting temperature of 1535 ° C.
• the stainless steel inner container may contain low-level radioactive waste.
• the inner container is ceramic.
• the ceramic inner container is very interesting for its resistance at a temperature of 1400 ° C.
• the ceramic inner container may contain highly radioactive waste.
• the cover comprises a steel outer wall, an inner wall of steel and a lead layer contained between the two steel walls.
• the bottom comprises a steel outer wall, a steel inner wall and a lead layer contained between the two steel walls.
• the inner container may comprise a removable cap.
• the inner container with the cap will completely isolate the radioactive waste.
• the container may comprise an inner rack with one or more compartments, the container or containers being disposed in said inner rack.
• the rack facilitates the arrangement of several containers inside the container.
• the interior rack may include one or more doors providing easy access to the compartment (s).
• the inner rack preferably comprises one or more centering means and / or one or more gripping means.
• the interior rack may include one or more holes to allow the sand to fill the space between the containers and the rack.
• the steel is stainless steel, preferably type 316L steel.
• the composition of stainless steels may alternatively be that of other stainless steels used in the nuclear industry or also in other industries, for example in the marine field or in the field of secure closures of a dwelling.
• the container further comprises a layer of plastics coating the radioactive waste in the inner container.
• the plastic layer blocks an additional portion of the radioactive radiation.
• the container preferably comprises an outer rubber envelope covering the outer wall.
• Fig. 1 is a sectional view of a container according to the invention and in a first embodiment
• Fig. 2 is a sectional view of a container according to the invention and in a second embodiment.
• FIG. 1 illustrates a container 10 for radioactive waste according to a first embodiment of the invention.
• the container 10 for radioactive waste comprises an outer wall 12 of steel, an inner wall 14 made of steel, a lead layer 16 contained between the two steel walls 12 and 14, a bottom 18 made of steel, a cover 20 made of steel, a volume 22 of quartz sand inside the container and at least one inner container / cassette / box 24i and 24 2 coated / circled / covered at least partially by the volume of quartz sand 22 (represented by crosses in the image).
• the radioactive waste 26 is located inside the container 24.
• bottom 18 and lid 20 of the container 10 is meant that once assembled the inner wall, the bottom 18 and the lid 20 of the container form an inner envelope of waste insulation 26.
• This envelope interior defines an interior space in which are housed the containers 24i and 24 2 with the waste 26 and the quartz sand 22.
• the bottom 18 of steel is a wall receiving the container and the outer and inner walls 12 and 14 which extend from the bottom 18 to the lid 20, around the container 24i and 24 2 .
• the bottom forms a circular outline, it can alternatively form an oval, square or any polygonal shape.
• the walls External and internal peripherals and the lid may be of corresponding or different shape.
• the inner and outer walls 12 and 14 may be made for example by welding two steel sheets preliminarily rounded. The inner and outer walls 12 and 14 are welded at their lower edge on the bottom 18 of steel. Preliminarily molten lead or lead alloy is then poured between the inner and outer walls to form the lead layer 16. In case of fusion, the lead layer 16 does not spread inside the container. Furthermore, the bottom 18 may be flat or comprise particular shapes, for example for the positioning of the container or containers 24 1 and 24 2 .
• the outer wall is of circular section with an outer diameter of between 500 mm and 1000 mm.
• the container is from a height between the bottom and the lid of between 800 mm and 1500 mm.
• the inner and outer walls 12 and 14 are of a thickness of between 3 mm and 10 mm and the lead layer 16 is of a thickness of between 25 mm and 50 mm.
• the bottom 18 of steel and the steel cover may be of a thickness equal to more than twice, for example three times the value of the thickness of the inner and outer walls 12 and 14.
• the container 10 comprises a circular ring 19 for fixing the cover 20 made of steel and mounted on the upper end of the outer and inner walls 12 and 14.
• the fixing ring 19 comprises orifices for receiving bolts for fixing the lid. passing through corresponding holes on the cover 20 steel.
• quartz sand silica sand with traces of different elements such as Al, Li, B, Fe, Mg, Ca, Ti, Rb, Na, OH. Quartz sand has the property of vitrifying after melting then hardening. Quartz sand with a low melting point will be chosen. The volume of glass thus formed can also block some of the radioactive radiation (for example with a premix of the quartz sand with a radiation absorbing material).
• the outer wall 12 comprises a pressure relief valve 40.
• the container 10 further comprises racking means 50 or rack / display comprising one or more superimposed compartments 52i and 52 2 receiving the two containers 24i and 24 2 .
• the compartments each include a door (not shown) allowing easy access to the interior of the compartments.
• the inner rack 50 comprises a bottom wall 53 in contact with the bottom 18 of the container 10, an upper wall 54, a cylindrical wall 56 extending between the lower and upper walls 53 and 54, and an intermediate wall. 58 forming a bearing between the lower and upper walls 52 and 54.
• the first container 24i is disposed on the bottom wall 52 of the inner rack 50.
• the second container 24 2 is deposited on the intermediate wall 58.
• the side wall 56 comprises several holes or orifices 60.
• the inner rack 50 is disposed inside the container before the quartz sand.
• the holes 60 in the side wall 56 of the inner rack 50 allow the passage of quartz sand in the compartments 52i and 52i to surround and call the containers 24i and 24 2 .
• the sand may also cover the containers 24 1 and 24 2 . It is noted that the sand could also be deposited beforehand under the container 24i.
• the inner rack 50 may comprise vertical / horizontal / diagonal uprights, and trays connected to the uprights; the quartz sand can thus surround / coat the containers by passing through the uprights and trays.
• the inner rack 50 is made of stainless steel.
• the inner rack 50 comprises a second upper wall 54 'and a lead plate 70 disposed between the two upper walls 54 and 54'.
• the inner containers 24 1 and 24 2 comprise a removable cap 28 1 and 28 2 as well as connecting means / flange (s) / clips / screws 30 1 and 30 2 of the removable cap to the container 24 1 and 24 2 .
• the inner containers 24 1 and 24 2 comprise centering means and / or one or more gripping means / hook / eyelet (not shown), for example on the lid 20.
• the container 10 comprises two inner containers 24i and 24 2 ceramic, preferably ceramic type ACA 997, more preferably special ceramic ACS 99.8LS 172.
• the container 24i and 24 2 with its cap 28 1 and 28 2 has a height of between 250 mm and 300 mm.
• the container 24 1 and 24 2 has a capacity of between 10 L and 20 L and is resistant to temperatures up to 1400 ° C.
• the waste 26 placed in the container 24i and 24 2 are highly radioactive.
• this embodiment is intended for the storage of long-lived medium and high-level radioactive waste, and in particular the non-upgraded final waste containing fission products and minor actinides, nuclear fuel ash.
• the container 10 further comprises an outer casing of rubber / plastic / silicone 80 covering the outer wall 12.
• the outer casing 80 of rubber is partially represented on the image at the lower zone of the container 10
• the outer rubber cover 80 is made by dipping the container 10 in a liquefied rubber bath.
• the outer shell 80 will prevent degradation of the container by water.
• FIG. 2 illustrates a second embodiment of the container 10 seen in relation to FIG. 1. They will have in common the characteristics described in connection with the first embodiment of FIG.
• the reference numbers of FIG. 2 are used in FIG. 1 for the corresponding elements, these numbers however being increased by 100 for the second embodiment illustrated in FIG. 2.
• Specific reference numbers are used for a specific element, these numbers being between 100 and 200.
• the container comprises a single inner container 124.
• the inner container 124 is placed in a single compartment 152 of the inner rack 150.
• the inner container 124 is made of stainless steel.
• the inner container 124 with its cap 128 has a height of between 500 mm and 1000 mm.
• the inner container 124 has a capacity of between 50 L and 350 L.
• the waste 126 located in the inner vessel 124 are weakly radioactive.
• waste is metal structures of fuel elements, resulting from the operation of the reactor, used gloves, protective suits, irradiated tools, hulls, tips, radioactive residues that may pose problems of chemical toxicity if Uranium is present along with other otherwise toxic products such as lead, arsenic, mercury, etc., radioactive waste from the medical sector and whose half-life is less than 100 days.
• the container 100 also comprises a plastic layer 190, preferably a low density polymer, covering the radioactive waste in the inner container 124.
• the plastic may be liquefied and mixed beforehand. with a charge and / or come from several low / high density polymers.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Processing Of Solid Wastes (AREA)
• Packages (AREA)

Applications Claiming Priority (2)

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• 2017
  • 2017-04-07 LU LU100166A patent/LU100166B1/fr active IP Right Grant
• 2018
  • 2018-04-05 CN CN201880033152.8A patent/CN110709944A/zh active Pending
  • 2018-04-05 CA CA3058277A patent/CA3058277A1/fr active Pending
  • 2018-04-05 EP EP18715703.7A patent/EP3607561B1/de active Active
  • 2018-04-05 EA EA201992292A patent/EA037732B1/ru unknown
  • 2018-04-05 WO PCT/EP2018/058753 patent/WO2018185233A1/fr active Application Filing
  • 2018-04-05 US US16/603,414 patent/US11367538B2/en active Active

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