Radiation-proof and anti-collision radioactive waste container

Abstract

An anti-radiation and anti-impact radioactive waste container, the anti-radiation and anti-impact radioactive waste container comprising: a radioactive waste storage container (10, 100) defining an internal space having an anti-radiation cylindrical or polygonal cavity, the radioactive waste storage container (10, 100) being disposed in the internal space, the radioactive waste storage container (10, 100) being disposed in the internal space, and the radioactive waste storage container (10, 100) being disposed in the internal space. 100) comprises: a stainless steel outer wall (12, 112); inner walls (14, 114) made of stainless steel; a low carbon steel layer (16, 116) between the inner wall and the outer wall; a stainless steel bottom (18, 118); a lead liner (53, 153) covering the inner wall and the bottom, the lead liner (53, 153) being separated from the cavity by a beaker-shaped stainless steel enclosure (56, 156); comprising a lead layer (541, 154 '), the stainless steel top (54, 154) being used to close the cavity; one or more internal radioactive waste vessels (24i, 242, 124) for radioactive waste (26, 126); quartz sand (22, 122), which at least partially fills the space of the cavity that is free after insertion of the internal radioactive waste vessel; and a cover (20, 120) made of stainless steel, which closes the container. The cover (20, 120) is made of stainless steel.

Description

Technical Field

[0001] The present invention generally relates to the field of safe transportation and storage of long-lived radioactive waste. In particular, the present disclosure relates to a container for storing low to high activity long-lived radioactive waste, which has enhanced resistance to leakage due to mechanical stress. Background Art

[0002] Containers for the storage of radioactive waste are well known in the art. Their main function is to contain the nuclear waste in such a way as to allow long-term or even ideally permanent storage to ensure long-term protection for humans and the environment. Depending on the waste itself and the type of storage intended, a large number of solutions have been proposed, reflecting different requirements.

[0003] In fact, although nuclear waste has different sources and characteristics, such as spent fuel from nuclear power plants, radioactive elements from medical or industrial use, or simply materials that have come into contact with radioactive elements, to date, most of the waste cannot be recycled or reused.

[0004] In fact, the vast majority of radioactive waste, about 90%, is low-activity, short-lived radioactive waste that is not practical to recycle. Decades ago, the choice was made to manage this waste by building industrial-scale surface storage centers.

[0005] The remaining 10% of radioactive waste is long-lived radioactive waste of medium to high activity. While some form of recycling is possible for this type of waste, its storage in deep geological formations with the goal of developing underground storage facilities and technologies has been debated for decades. Appropriate practical solutions are still under discussion, and the long-term management of this type of nuclear waste remains to be determined. In the meantime, for at least the next few decades, this nuclear waste will be stored industrially in dedicated buildings on the surface, awaiting its more permanent and safer disposal options.

[0006] Radioactive waste can be classified according to two criteria: radioactivity and radioactive decay period.

[0007] The radioactivity of any radioactive material represents the number of nuclear disintegrations that occur per second and is measured in becquerels (1 Bq = 1 disintegration per second).

[0008] Some examples of activities are:

[0009] 1kg of rainwater: about 1Bq (natural radioactivity);

[0010] 1kg of granite soil: about 10 4Bq (natural radioactivity);

[0011] 1kg of uranium ore: about 10 5 Bq (natural radioactivity);

[0012] 1kg of freshly discharged spent nuclear fuel*: Approximately 10 14 Bq.

[0013] * Activity decreases over time. After 10 years, the activity of nuclear fuel has dropped to about one-sixth of its original value.

[0014] By definition, the radioactive decay period or in short their "period" or "half-life" is the time required for the radioactivity of a material to fall to half of its initial value. The half-life does not depend on the mass of the material under consideration. Each pure radionuclide has a completely known period, whose values ​​can range from less than a thousandth of a second (such as polonium 214: 0.16 ms) through all intermediate values ​​(such as iodine 131: 5 days, cesium 137: 30 years, plutonium 239: 24 000 years, uranium 235: 7 million years, etc.) to billions of years (such as uranium 238: 4.5 billion years). If different radionuclides are present, the value of the radioactive decay period is taken as the longest half-life of all the radionuclides. In addition, since an initially short-lived radionuclide may decay to produce a longer-lived daughter nuclide, the half-life of the longest-lived daughter nuclide is adopted.

[0015] From the perspective of the two criteria of "activity" and "period", the classification according to activity reflects the technical precautions that need to be taken in radiation protection, while the classification according to period reflects the duration of potential hazards.

[0016] Regarding the activity standard,

[0017] - If the activity level is less than one hundred becquerels per gram (an order of magnitude of naturally occurring radioactivity), the waste is said to have “very low activity”;

[0018] - Waste is said to be of "low activity" if its activity level is between tens of becquerels per gram and hundreds of thousands of becquerels per gram and its radionuclide content is low enough that it does not require protection during ordinary handling and transportation operations;

[0019] - waste is said to be "medium active" if its activity level is between about one million and one billion becquerels per gram (1 MBq / g to 1 GBq / g);

[0020] - Waste is said to be "highly active" if its activity level is of the order of several billion becquerels per gram (GB / g), for which the specific power is of the order of 1 Watt per kilogram, and is therefore called "hot" waste.

[0021] Regarding the cycle standard,

[0022] - waste is said to have a “very short lifespan” if its lifespan is less than 100 days (which allows it to be managed through radioactive decay and disposed of as normal industrial waste after a few years);

[0023] - waste is called “short-lived” if its radioactivity comes mainly from radionuclides with lifetimes of less than 31 years (which ensures that it disappears within a few centuries);

[0024] - Waste is said to be “long-lived” if it contains significant amounts of radionuclides with lifetimes exceeding 31 years (which would require containment and dilution management compatible with geological timescales).

[0025] In general, after 10 times the half-life of a radionuclide, its activity is divided by 1024, which allows it to pass from one activity category to another. Thus, after 310 years, a "medium activity short-lived" waste becomes no more than a "low activity short-lived" waste, and another three centuries will bring it into the "very low activity" category.

[0026] Other classification criteria relate to the chemical risks and physicochemical properties of the waste. Radioisotopes are more dangerous because they are highly radioactive, chemically toxic, and can be easily transferred to the environment.

[0027] Radioactive waste that requires elaborate and specific protective measures is Highly Active and Long-Lived (HALL waste). This waste is usually active enough to cause burns if you are exposed to it for too long. HALL waste comes mainly from spent fuel from nuclear power plants.

[0028] For the sake of convenience and because of the serious consequences for humanity posed by high-activity wastes, it may now become necessary, according to the precautionary principle, to base the radiation protection of such high-activity wastes on geological containment installations. These radioactive wastes will be stored in deep geological formations and in a permanent manner. However, despite the fact that their radioactivity will remain significant for hundreds of thousands or even millions of years, it will not be possible to have this degree of precautions, regardless of the fact that these wastes will be transformed over time into "low-activity, long-lived" wastes. Moreover, to date, nothing has been able to guarantee the tightness of the container (whatever it may be) and the stability of the rock over such long periods. Therefore, the radioactivity will inevitably rise to the surface by uncontrolled contamination of important elements (water, soil, etc.) over very large areas.

[0029] The alternative option of storing the HALL waste "underground", ie at a depth of, for example, no more than 5 m below ground and in a monitored location, allows easy access to the waste in the event of future recycling.

[0030] However, there are other risks that must be considered.

[0031] One such risk is related to the fact that radioactive waste is generally not stored at the site where it is generated. This means that the waste must ideally be transported directly from its initial location to its final storage site, but more often than not, transportation involves more than one stopover before the waste reaches its destination. While transportation itself already contains risks such as transport accidents, such as collisions, derailments and similar accidents, there are also other risk situations, such as, in particular, fire.

[0032] There is an additional risk, primarily during transport, but also during temporary storage at lower depths or even underground, of a potential attack by terrorists with the aim of causing or at least receiving radioactive contamination in more or less important areas in order to achieve their political aims. Likewise, the resulting fires could have a further impact on the overall number of casualties.

[0033] Although HALL radioactive waste such as spent nuclear fuel is generally stored in complex and highly secure so-called dry cask storage containers (such as or Although radioactive waste can be transported in containers, there is still a need to provide solutions for large quantities of low to medium activity and / or short-lived radioactive waste.

[0034] For example, WO2018 / 185233 discloses a container for radioactive waste, the container comprising: a steel outer wall; a steel inner wall; a lead layer located between two steel walls; a steel bottom; a steel cover; a certain volume of quartz sand located inside the container; at least one inner vessel / cassette / inner box, which is at least partially covered, coated, surrounded, covered by a certain volume of quartz sand; and radioactive waste located inside the container. Due to the special configuration of the lead layer and the quartz sand layer, etc., the temperature resistance and therefore the integrity of the container are increased for a longer time in the event of a fire, even in the event of a fire at very high temperatures. However, enhanced protection against impacts, such as collisions during transportation, or even impacts caused by explosions or armed attacks, is also desired.

[0035] Technical issues

[0036] Therefore, the object of the present disclosure is to further improve the safety of radioactive waste containers, more particularly to improve the resistance of radioactive waste containers to any type of mechanical damage, but especially to mechanical damage caused by impacts, especially during transportation, and in particular during preparation for their storage on the surface or underground. Summary of the invention

[0037] To achieve this object, the present invention provides, in a first aspect, a radiation-proof and impact-proof radioactive waste container (cask), the radiation-proof and impact-proof radioactive waste container comprising: a radioactive waste storage container, the radioactive waste storage container defining an inner space having a cylindrical or polygonal cavity, the radioactive waste storage container comprising:

[0038] - an outer wall made of stainless steel facing the outside;

[0039] - Stainless steel inner wall facing the interior space;

[0040] - a mild steel layer between the stainless steel inner wall and the stainless steel outer wall;

[0041] - bottom made of stainless steel;

[0042] a continuous lead lining covering the stainless steel inner wall and the stainless steel bottom on the side of the stainless steel inner wall and the stainless steel bottom facing the cylindrical or polygonal cavity and separated from the cavity by a beaker-shaped stainless steel enclosure;

[0043] - a stainless steel top including a lead layer, the stainless steel top being configured to hermetically close the radiation-proof cylindrical or polygonal cavity (i.e. the space defined within the beaker-shaped stainless steel enclosure);

[0044] - one or more internal radioactive waste vessels configured to contain radioactive waste and placed within the radiation-proof cylindrical or polygonal cavity;

[0045] - a volume of quartz sand which at least partially fills the space of the radiation shielding cylindrical or polygonal cavity which remains vacant after the insertion of one or more internal radioactive waste vessels; and

[0046] - A stainless steel cover which is attached to the radioactive waste storage container and hermetically closes the radioactive waste storage container.

[0047] Previous solutions, such as the radioactive waste container disclosed in WO2018 / 185233, provide reliable and long-term protection against radiation leakage even in the event of a fire. However, such containers may not be able to withstand significant mechanical stresses from the outside, such as impacts in the event of a fall from a certain height, impacts in the event of an accident during transportation, against explosions caused by, for example, a nearby fire, or even against intentional damage in the event of an armed attack.

[0048] Now, the inventors have devised a method that significantly improves the inherent resistance to mechanical stresses from the outside, such as explosions, accidental or intentional mechanical impacts, while maintaining the advantageous properties of resistance to damage due to fire. A layer of mild steel is placed between the stainless steel inner wall and the stainless steel outer wall, which significantly improves the resistance of the radioactive container to mechanical shocks and impacts, such as those caused by falling from a height of several meters, collisions during transportation, or the explosion of a close explosion.

[0049] In the context of the present invention, low carbon steel generally has a carbon content of between 0.05% and 0.29% at most, with a relatively high melting point between 1450°C and 1520°C. Low carbon steel has advantageous properties such as high tensile strength, high impact strength, good ductility, good weldability, and good forgeability and cold formability. However, low carbon steel does not have high corrosion resistance without protection. This is achieved in the present invention by sealing between two stainless steel walls to provide appropriate corrosion protection. Some suitable low carbon steel grades are: such as EN1.0301 (equivalent grades: AISI 1008; C10; DC01), containing 0.1% carbon, 0.4% manganese and 0.4% silicon. It also contains small amounts of copper (Cu), nickel (Ni), chromium (Cr), aluminum (Al) and molybdenum (Mo); EN1.1121 (equivalent grade: AISI 1010) contains 0.08% to 0.13% carbon. Manganese is present in the range of 0.3% to 0.6%; EN 1.0402 (equivalent grade: AISI 1020; C22), with a carbon content from 0.18% to 0.23%: wherein the manganese content ranges from 0.3% to 0.6%.

[0050] Protection against radiation is provided by a continuous (integral) lead layer covering both the stainless steel inner wall and the stainless steel bottom. Such a continuous layer may be obtained by placing a beaker-shaped or kettle-shaped stainless steel enclosure having outer dimensions smaller than the cavity formed by the inner wall and the bottom within the cavity, such that it is located at a determined and uniform distance from the inner wall (e.g., by temporarily attaching structures or using discrete spacers in appropriate locations to hold the enclosure in a predetermined position), and pouring molten lead into the space formed between the inner wall, the bottom and the beaker-shaped enclosure. The advantage of the process of providing such a continuous lead lining is that potential radiation gaps at the contact area between the inner wall and the bottom are completely avoided. Such a continuously poured lead lining further protects the exterior even if the temperature within the container rises above the melting point of lead due to heat released within the vessel due to radioactive decay and / or heat from the outside (such as in the case of a fire).

[0051] Furthermore, in the event that the decay heat generated when the radiation acts on the material due to the conversion of the energy of alpha, beta or gamma radiation into thermal motion of atoms becomes very high, a volume of quartz sand and radioactive waste located within the container will further enhance the resistance to high temperatures and will ensure the integrity of the container even at very high temperatures.

[0052] In fact, this enhanced heat resistance is due to the fact that when the heat in the container rises, the lead first sandwiched between the stainless steel inner wall and the beaker-shaped stainless steel enclosure will absorb a large amount of heat until the lead is completely melted at a temperature of about 327°C. If the temperature in the container continues to rise, a certain volume of quartz sand used to fill the space in the cavity vacant due to the vessel (which previously played a major role in maintaining the internal vessel in place and protecting the internal vessel from impacts on the container) will begin to melt at about 1300°C to 1600°C, depending on the purity of the quartz sand, thereby absorbing a further large amount of heat energy. In this case, depending on the material used for the vessel and the grade of stainless steel, it may be desirable or necessary to reduce the melting point of the quartz sand to a lower value, such as, for example, below the melting point of some or all of the stainless steel used. In this case, one or more fluxes such as sodium carbonate, potassium carbonate, calcium oxide, etc. can be added to the quartz sand.

[0053] The temperature of the layer of lead, respectively sand, which is partly molten and partly solid, will not rise above the melting temperature of the lead, respectively sand, as long as any part of the lead, respectively sand, remains in the solid state. The boiling point of lead will represent a further temperature stability point (plteau) at about 1700°C.

[0054] According to an advantageous embodiment of the invention, the thickness of the lead lining is between 25 mm and 50 mm. The minimum thickness of the volume of quartz sand between the vessel and the inside of the beaker-shaped stainless steel enclosure is preferably at least 2 cm, more preferably at least 3 cm. The maximum thickness of the quartz sand volume is preferably less than 10 cm, more preferably less than 8 cm, and in particular less than 6 cm.

[0055] According to an advantageous embodiment, the radioactive waste storage container comprises a pressure relief valve. This valve will allow the evacuation of gases generated by the melting / boiling of the lead contained in the space between the stainless steel inner wall and the stainless steel bottom and the beaker-shaped stainless steel enclosure.

[0056] One or more inner vessels can be made of stainless steel. The stainless steel inner vessel will not melt before reaching a melting temperature of 1535°C. The stainless steel inner vessel can hold, for example, low-level radioactive waste. According to another preferred embodiment, the inner vessel is made of ceramic (material), wherein the ceramic (material) can be selected from oxide ceramics, non-oxide ceramics and mixtures thereof, including so-called refractory materials, such as refractory concrete, refractory cement, refractory castables, etc. The ceramic inner vessel is still very attractive in its resistance at a temperature of 1400°C or higher, or even above the melting temperature of stainless steel. The ceramic inner vessel can hold, for example, high-level radioactive waste. The performance of the vessel can be further improved by reinforcing fibers, including steel fibers or superalloy fibers, and austenitic nickel-chromium-based superalloys are some examples thereof, such as Inconel 600, 625, X-750, etc.

[0057] One or more inner vessels may include an attachment cap, and both the inner vessel and the cap are preferably made of the optional reinforced ceramic material described above. Advantageously, the cap is attached to the vessel by a removable clamp. Only the inner vessel will contain radioactive waste to physically isolate the radioactive waste from the rest of the radioactive waste storage container. Advantageously, a layer of plastic material is provided on top of the radioactive waste in the inner vessel, serving as an additional sealant and desired neutron capturer. Suitable plastic materials may include materials such as polyethylene (PE, such as LDPE, HDPE, HDPE, etc.) or thermoplastic natural rubber of a high-density polyethylene / natural rubber (HDPE / NR) mixture, preferably boronized / containing boron carbide.

[0058] In particular, when more than one vessel is to be stored in a radioactive waste storage container, preferably, the radioactive waste storage container comprises an internal shelf, which comprises a corresponding number of compartments, and one or more vessels are arranged in the internal shelf (compartment). The shelf facilitates the arrangement of several vessels in the radioactive waste storage container. Since the space of the radiation-proof cylindrical or polygonal cavity remaining after inserting one or more internal radioactive waste vessels is subsequently filled with a certain volume of quartz sand, the shelf is provided with appropriate channels for quartz sand to facilitate the distribution of the quartz sand in the space. Since the shelf does not need to significantly support the vessel once the quartz sand fills the surrounding space, in a particularly advantageous embodiment, the shelf has a simple linear or mesh structure. The shelf may include one or more shelf positioning devices and / or one or more gripping devices for facilitating the correct placement of the shelf in the radiation-proof cylindrical or polygonal cavity, and / or one or more vessel centering devices for facilitating the correct placement of the vessel.

[0059] The stainless steel of the stainless steel inner wall and / or the stainless steel outer wall is preferably austenitic stainless steel, such as EN1.4310, EN1.4301, EN1.4307, EN1.4305, EN1.4541, EN1.4401, EN1.4404 or EN1.4571, preferably AISI316L (AISI, American Iron and Steel Institute) / EN1.4404 stainless steel. In addition, the stainless steel of the stainless steel inner wall and / or the stainless steel outer wall can be martensitic stainless steel, such as EN1.4006, EN1.4021, EN1.4116, EN1.4104, EN1.4122, EN1.4125, EN1.4057, EN1.4418 or EN1.4542, preferably AISI410 or 420 / EN1.4021 stainless steel.

[0060] In order to further protect the radioactive waste storage container or radioactive waste vessel (also simply referred to as the inner vessel), the protection of both the radioactive waste storage container and the radioactive waste vessel or the protection of either the radioactive waste storage container and the radioactive waste vessel may also include an outer shell or outer casing, which includes one or more layers of materials such as rubber, plastic, silicone or a mixture thereof or is made of one or more layers of materials such as rubber, plastic, silicone or a mixture thereof, and the outer shell or outer casing at least partially covers the outer wall of the radioactive waste storage container and / or the wall of the inner vessel. The provision of such an outer casing at least below the bottom and its lower part advantageously reduces even the slightest sliding of the container during transportation. In addition, an outer shell or outer enclosure comprising or made of one or more layers of the following suitable materials, such as thermoplastic natural rubber (which is optionally boronized / containing boron carbide) of polyethylene (PE, such as LDPE, HDPE, UHMWPE, etc.) or a high-density polyethylene / natural rubber (HDPE / NR) mixture, is provided on the entire outer surface of the radioactive waste inner vessel and / or the radioactive waste storage container, which can additionally serve as the desired neutron capture.

[0061] In order to further enhance the resistance to mechanical stresses from the outside, at least during transportation or even before final storage, such as in deep geological disposal, the radiation- and impact-proof radioactive waste container advantageously also includes (at least temporarily) a removable outer transport tank, wherein the removable outer transport tank comprises a hollow cylindrical or polygonal body with a lower end and an upper end, the hollow cylindrical or polygonal body being configured for adaptively receiving the radioactive waste storage container in the hollow cylindrical or polygonal body, wherein the lower end is closed by a fixed bottom and the upper part is closed by a removable tank cover, wherein the hollow cylindrical or polygonal body, the fixed bottom and the upper part are closed by a removable tank cover. The bottom and the removable tank cover consist of at least three layers: an outer layer made of armor-grade steel, preferably having a thickness of at least 15 mm; an inner layer made of high-strength steel, preferably having a thickness of at least 35 mm; and an intermediate layer between the outer layer and the inner layer, preferably having a thickness of at least 25 mm, the intermediate layer being made of one or more stratiforms comprising or consisting of ceramic material, wherein the ceramic material is selected from oxide ceramics, non-oxide ceramics and mixtures thereof, including so-called refractory materials such as refractory concrete, refractory cement, refractory castables, etc.

[0062] In order to facilitate the correct placement of the radioactive waste storage container in the removable external transport tank, the bottom of the removable external transport tank may include positioning blocks. Advantageously, the positioning blocks have a tapered shape that opens to its upper side to automatically center the radioactive waste storage container when the radioactive waste storage container is lowered into place. These positioning blocks can also provide: once the radioactive waste storage container is fully inserted into the transport tank, the radioactive waste storage container is kept in place. Similar centering blocks can also be set at appropriate positions on the inner side of the hollow cylindrical or polygonal body of the tank, or alternatively at appropriate positions on the outer circumference of the radioactive waste storage container. Alternatively or additionally, the removable external transport tank can also include an inner cover and / or an outer cover, which includes or is made of materials such as the optional outer shell for the radioactive waste storage container described above.

[0063] In a preferred embodiment, the radioactive waste storage container can also be secured by at least partially, preferably completely, filling the hollow cylindrical or polygonal body of the removable outer transport tank and any voids within the radioactive waste storage container with quartz sand. This volume of quartz sand not only helps to avoid any movement of the radioactive waste storage container during transport, but also further enhances its resistance to mechanical stress and its ability to resist fire.

[0064] Armour steels (sometimes also called military-grade steels or ballistic steels) that can be used for the outer layer of an external transport tank generally have a maximum carbon content of 0.32% by weight. However, the focus is obviously on their hardness. Simply put, their hardness (expressed in Brinell hardness) is calculated by comparing the amount of force applied to a piece of material and the size of the indentation of the force. More specifically, the Brinell hardness test involves applying a constant load (usually in the range of 500N to 3000N) to the flat surface of the workpiece for a specified period of time (10 seconds to 30 seconds), for example using a hardened steel ball or a tungsten carbide ball with a diameter of 5mm or 10mm. According to ISO 6506-1:2014, the Brinell hardness expressed in MPa (HBW, using a tungsten carbide ball) is obtained by:

[0065] HBW=0.102*2F / {πD[D-(D 2 -d 2 ) 1 / 2 ]}

[0066] Where D is the diameter of the ball (mm), d is the diameter of the recovered circular indentation (mm), and P is the applied load (kg). Therefore, HB is calculated by dividing the applied load by the surface area of ​​the indentation rather than the projected area.

[0067] The armor steel used for the outer layer of the outer transport tank preferably has a Brinell hardness HBW of at least 3900 MPa according to ISO 6506-1:2014. Suitable armor grade steels are, for example, A36, AR400, AR500, MIL-46100, MIL-12560 or MIL-46177. Although the outer layer is preferably made of one sheet of appropriate thickness, it may also comprise two or more superimposed (thinner) armor grade steel sheets if deemed necessary or desired.

[0068] According to ISO 6506-1:2014, the high strength steel of the inner layer generally has a Brinell hardness HBW between 2450 MPa and 3675 MPa. Suitable high strength steels are generally steels with a yield strength ranging between 210 MPa and 550 MPa and a tensile strength between 270 MPa and 700 MPa. Therefore, in the context of the present invention, the term "high strength steel" includes steels with a yield level above 550 MPa, which are generally referred to as advanced high strength steels, and when the tensile strength level exceeds 780 MPa, these steels are generally referred to as ultra-high strength steels. Likewise, although the inner layer is preferably made of one thick sheet, it may also comprise two or more thinner superimposed high strength steel sheets if it is considered necessary or desired.

[0069] The intermediate layer may comprise two or more layers and a backing of a tough fiber reinforcement layer or a metal foil, each layer comprising or consisting of a ceramic material, wherein the ceramic (material) may be selected from oxide ceramics, non-oxide ceramics and mixtures thereof, including so-called refractory materials, such as refractory concrete, refractory cement, refractory castables, etc., such as in particular aluminum oxide, boron carbide and / or silicon carbide, more preferably, the tough fiber is a braided para-aramid fiber, such as poly(p-phenylene terephthalamide), for example wait. K-29, K49, K119, K129, K149, AP, XP or KM2, or combinations thereof, are examples of suitable para-aramid fibers. If the backing in the middle layer is a metal foil, they can be made of similar materials as the outer or inner layers, i.e. armor grade steel, high strength steel or even mild steel grades used for radioactive waste storage containers. In the case of two or more layers, the layers are preferably positioned so that any junction between adjacent elements in one layer is placed in a staggered fashion with any element of the layer below or above.

[0070] In view of the need to safely contain, transport and store radioactive waste, despite the risks associated therewith, whether related to the nature of the contents of the internal radioactive waste containers, to external factors directly related to transportation, or even to risks from deliberate attack, it is desirable to provide radiation- and impact-proof radioactive waste containers - such as radioactive waste storage containers and / or external (radioactive waste) transport tanks - with autonomous (such as battery-supported) monitoring and / or transmission devices, which are configured to: use appropriate sensors, such as GPS trackers, motion detectors, temperature sensors, humidity sensors and / or pressure sensors, etc., to record and / or transmit (as required, changed or planned) identification and physical data about the radioactive waste storage containers and / or external transport tanks, such as its / their identity, integrity, location, movement, internal temperature and / or external temperature, humidity and / or pressure, etc. For example, unauthorized flashbacks can be detected by unplanned movement, unexpected humidity, pressure and / or temperature changes outside or inside the radioactive waste storage container and / or the external transport tank. Therefore, it is also advantageous that the transmission device is configured to actively transmit appropriate alarms when the radiation- and impact-resistant radioactive waste container is unexpectedly moved and / or flashed back by providing information such as identity, integrity, location, movement, etc. for rapid intervention and protective measures. In an embodiment, the monitoring and / or transmission device of the external transport tank can be configured to (also) forward corresponding data and / or (also) amplify signals from the radioactive waste storage container contained therein.

[0071] Another aspect of the present invention is that the external transport tank is used to further temporarily protect the radioactive waste storage container - preferably the radioactive waste storage container is the radioactive waste storage container defined in this article or the radioactive waste container disclosed and claimed in WO2018 / 185233A1 - from mechanical damage during transportation and storage, such as impact in the event of a fall from a certain height, accidents during transportation, and resistance to intentional damage such as explosions caused by nearby fires or even armed attacks, thereby providing a radiation-proof and impact-proof radioactive waste container, wherein the external transport tank includes a hollow cylindrical or polygonal body having a lower end and an upper end, and the hollow cylindrical or polygonal body is configured to adaptively receive the radioactive waste storage container in the hollow cylindrical or polygonal body. A tank body in which the lower end is closed by a fixed bottom and the upper part is closed by a removable tank cover, wherein the hollow cylindrical or polygonal body, the fixed bottom and the removable tank cover consist of at least three layers: an outer layer made of armor-grade steel, preferably having a thickness of at least 15 mm; an inner layer made of high-strength steel, preferably having a thickness of at least 35 mm; and an intermediate layer between the outer layer and the inner layer, preferably having a thickness of at least 25 mm, wherein the intermediate layer is made of one or more stratiforms comprising or consisting of ceramic material, wherein the ceramic material is selected from oxide ceramics, non-oxide ceramics and mixtures thereof, including so-called refractory materials such as refractory concrete, refractory cement, refractory castables, etc.

[0072] The present disclosure also describes, in another aspect, a method for further temporarily protecting a radioactive waste storage container - preferably the radioactive waste storage container is the radioactive waste storage container defined in this article or the radioactive waste container disclosed and claimed in WO2018 / 185233A1 - from mechanical damage during transportation and storage - such as impact in the event of a fall from a certain height, accidents during transportation, resistance to deliberate damage such as explosions caused by nearby fires or even armed attacks - thereby providing a radiation-proof and impact-proof radioactive waste container, the method comprising: providing an external transport tank, the external transport tank comprising a hollow cylindrical or polygonal body having a lower end and an upper end, the hollow cylindrical or polygonal body being configured to adaptively receive the radioactive waste storage container in the hollow cylindrical or polygonal body, wherein the lower end is closed by a fixed bottom, and the upper part is closed by a removable tank cover closed, wherein the hollow cylindrical or polygonal body, the fixed bottom and the removable tank cover are composed of at least three layers: an outer layer made of armor-grade steel, preferably having a thickness of at least 15 mm; an inner layer made of high-strength steel, preferably having a thickness of at least 35 mm; and an intermediate layer between the outer layer and the inner layer, preferably having a thickness of at least 25 mm, wherein the intermediate layer is made of one or more stratiforms comprising or consisting of ceramic material, wherein the ceramic material is selected from oxide ceramics, non-oxide ceramics and mixtures thereof, including so-called refractory materials such as refractory concrete, refractory cement, refractory castables, etc.; placing a radioactive waste storage container into the radioactive waste transport tank; optionally filling any remaining voids in the radioactive waste transport tank with quartz sand; and sealing the radioactive waste transport tank by firmly closing the tank cover.

[0073] Since radioactive waste transport casks will mainly be used during transport or even during temporary storage in facilities at the surface or at a reduced depth underground, i.e. the risk of mechanical stress cannot be excluded, a further aspect of the invention is a kit of parts comprising a first number of radioactive waste storage containers as described herein and a second number of external transport casks as disclosed herein, wherein the first number is greater than the second number. In fact, when the radiation- and impact-proof radioactive waste container including the external radioactive waste transport cask reaches its final destination, such as at a deep geological disposal site, the radioactive waste storage container can be removed from the radioactive waste transport cask and stored, and its radioactive waste transport cask can be reused in order to safely transport further radioactive waste transport casks. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Preferred embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0075] Figure 1 is a schematic cross-sectional view of a first preferred embodiment of a radiation and impact resistant radioactive waste container comprising a radioactive waste storage container 10 and a removable outer transport tank 200; and

[0076] Figure 2 is a schematic cross-sectional view of a second preferred embodiment of a radiation and impact resistant radioactive waste container comprising a radioactive waste storage container 100 and a removable outer transport tank 200 .

[0077] Further details and advantages of the invention will become apparent from the following detailed description of several non-limiting embodiments with reference to the accompanying drawings. DETAILED DESCRIPTION

[0078] Figure 1 and Figure 2 A preferred embodiment of a radiation and impact proof radioactive waste containment vessel is shown, which comprises a radioactive waste storage container 10 , 100 additionally temporarily protected by a removable outer transport cask 200 .

[0079] exist Figure 1 In the embodiment of the present invention, a radioactive waste storage container 10 according to a first embodiment of the present invention comprises: a stainless steel outer wall 12; a stainless steel inner wall 14; a low carbon steel layer 16, which is contained between the two stainless steel walls 12 and 14; a stainless steel bottom 18; a stainless steel cover 20; a continuous lead lining 53, which is cast in a molten state between the stainless steel inner wall 14, the stainless steel bottom 18 and the beaker-shaped stainless steel enclosure 56; a stainless steel top 54 having a lead layer 54'; a certain volume of quartz sand 22, which is located in the beaker-shaped stainless steel enclosure 56; and at least one inner vessel 241 and 242 (in Figure 1 and Figure 2 The radioactive waste 26 is located in the container 24 .

[0080] A beaker-shaped stainless steel enclosure 56 and a stainless steel top 54 including a lead layer 54', wherein the lead layer 54' is preferably enclosed within a double layer of the stainless steel top 54, define an inner enclosure in which vessels 241 and 242 with waste 26 are accommodated and which is further held in place by a volume of quartz sand 22.

[0081] The radioactive waste storage container 10 preferably has a circular cross-section. Alternatively, the radioactive waste storage container 10 may have an elliptical, square or any polygonal shape. The stainless steel inner wall 12 and the stainless steel outer wall 14 having a layer of sandwiched mild steel 16 may be made, for example, by welding two stainless steel sheets and a mild steel layer placed between the two stainless steel sheets, the sheets having been appropriately rounded in advance. The combined stainless steel inner wall 12 and the stainless steel outer wall 14 and their mild steel layer 16 are welded to the stainless steel bottom 18 at their lower edges, and the stainless steel bottom 18 may also be composed of the same three layers as the body of the radioactive waste storage container. The beaker-shaped stainless steel enclosure 56 is then placed in the interior space of the cylindrical or polygonal cavity with radiation protection, at a distance from the stainless steel inner wall 14 and the stainless steel bottom 18. This may be held in place by an external device (not shown) or by providing a discrete number of (lead) spacers (not shown). Then, molten lead or lead alloy is poured between the inner wall 14 and the beaker-shaped stainless steel enclosure 56 to form a continuous lead lining 16. Therefore, even in the case of melting, the lead layer 16 will not spread in the container. In addition, the stainless steel bottom 18 can be flat or can include a specific shape, such as for positioning the vessels 241 and 242 or the shelf 50.

[0082] Generally, the outer wall is a circular cross section with an outer diameter between 500 mm and 2000 mm. The container generally has a useful internal height between 800 mm and 5000 mm, which is measured between the bottom of the beaker-shaped stainless steel enclosure 56 and the inside of the stainless steel top. Such sizes are generally advantageous because they are easily compatible with conventional cargo transportation in terms of size and allowable weight. An outer wall with a circular cross section generally provides the best performance in terms of resisting both external and internal forces generated, for example, due to mechanical shock and impact. Of course, it is clear that other sizes, shapes and total weights are also within the scope of the present disclosure.

[0083] The thickness of the inner wall 12 and the outer wall 14 is generally between 3 mm and 10 mm, and the mild steel layer 16 may have a thickness between 10 mm and 50 mm. The thickness of the wall of the beaker-shaped stainless steel enclosure 56 may be less than the thickness of the inner wall 12 and the thickness of the outer wall 14, such as from 1.5 mm to 5 mm. The continuous lead lining 53 may have a thickness between 25 mm and 50 mm. The thickness of the stainless steel bottom 18 and the stainless steel cover 20 may be equal to or more than twice the thickness of the inner wall 12 and the thickness of the outer wall 14, such as three times the thickness.

[0084] The container 10 includes a circular ring 19 attached to the upper ends of the inner wall 12 and the outer wall 14 for fixing and sealingly closing the stainless steel cover 20. The fixing ring 19 includes holes for receiving bolts, which are used to pass through corresponding holes in the stainless steel cover 20 to fix the cover 20.

[0085] Quartz sand refers to silica sand with trace amounts of different elements such as Al, Li, B, Fe, Mg, Ca, Ti, Rb, Na, OH. Quartz sand has the property of vitrification after melting and then hardening. Quartz sand with a low melting point will be selected, or a suitable flux will be added. The resulting integral volume of glass can also block some radioactive radiation (for example, using a premix of quartz sand and radiation absorbing material to block).

[0086] The radioactive waste storage container 10 includes a pressure relief valve 40 for evacuating gases that are exhausted in the event that the lead lining 16 melts, for example.

[0087] The container 10 also includes a shelf 50 including one or more stacked compartments 521 and 522 for receiving two vessels 241 and 242. The shelf 50 is preferably made of a wire or mesh structure so as not to hinder the subsequent filling with quartz sand. The internal shelf 50 is made of stainless steel.

[0088] The inner vessels 241 and 242 comprise removable caps 281 and 282 and means 301 and 302 for fastening / flange connection / clamping / screwing from the removable caps to the vessels 241 and 242 .

[0089] The inner vessels 241 and 242 include centering means and / or one or more means for grabbing / hooking / attaching eyelets (not shown).

[0090] In this first implementation, the container 10 comprises two ceramic inner vessels 241 and 242, preferably made of ACA997 type ceramic, more preferably made of special ceramic ACS 99,8LS172. The vessels 241 and 242 with their caps 281 and 282 have a height between 250 mm and 300 mm. The vessels 241 and 242 have a capacity between 10 L and 20 L and withstand temperatures up to 1400 ° C.

[0091] The waste 26 placed in the vessels 241 and 242 is highly radioactive. In particular, the present embodiment is intended for storing long-lived medium to high-level radioactive waste, and in particular for storing final waste containing non-recyclable fission products and a few actinides, namely nuclear fuel ash.

[0092] In addition, the container 10 preferably also includes a rubber / plastic / silicone outer shell 80 covering the outer wall 12. The rubber / plastic / silicone outer shell 80 is only partially shown in the image at the lower area of ​​the container 10. The rubber / plastic / silicone outer shell 80 is made by immersing the container 10 in a corresponding liquid / liquefied rubber / plastic / silicone bath. The outer shell 80 will further prevent the container from being degraded by water and prevent the radioactive waste storage container from sliding. Advantageously, the rubber / plastic outer shell - such as an outer (high-density, HD) polyethylene (PE) shell or a thermoplastic natural rubber including a high-density polyethylene / natural rubber (HDPE / NR) mixture (optionally containing boron carbide) or an outer shell composed of a thermoplastic natural rubber of a high-density polyethylene / natural rubber (HDPE / NR) mixture (optionally containing boron carbide) - can additionally act as a neutron capturer.

[0093] Figure 1 Also shown is an external radioactive waste transport tank 200, in which the radioactive waste storage container 10 can be placed to further protect the radioactive waste storage container 10 from mechanical damage, especially to further protect the radioactive waste storage container 10 from mechanical damage during transportation or when subjected to armed attack. The radioactive waste transport container 200 includes a body, a bottom and a cover, each of which includes three layers: an outer layer 212, 222, 232; an inner layer 214, 224, 234; and an intermediate layer 216, 226, 236, wherein the outer layer 212, 222, 232 is made of armor-grade steel, the inner layer 214, 224, 234 is made of high-strength steel, and the intermediate layer 216, 226, 236 is made of a ceramic-containing material, preferably including two or more layers with a tough fiber reinforced layer or a backing of a metal foil, each layer including or consisting of a ceramic material, more preferably, the tough fiber is a braided para-aramid fiber. As shown in the figure, the corresponding steels are welded together by a weld 228 (other required welds are not necessarily shown).

[0094] The upper inner circumference of the tank cover and the tank body is preferably provided with complementary thread means 239 to allow the tank cover to be hermetically closed on the tank body. The tank cover or the tank body may be provided with a means such as an eyelet 238, which is used to facilitate closing the cover or transporting the entire radiation and impact resistant radioactive waste container.

[0095] Advantageously, the interior size and shape of the radioactive waste transport jar 200 is adapted to snugly receive and hold the radioactive waste storage container 10 in place after the radioactive waste storage container 10 is fully inserted. However, it may be desirable to provide a positioning block 240 (or similar device) on the bottom (or side) of the radioactive waste transport jar 200, which not only facilitates correct positioning, but also holds the container 10 in place after the container 10 is inserted.

[0096] The void space 250 may be filled in whole or in part with quartz sand to further enhance the ability of the radiation-proof and impact-proof radioactive waste container to resist mechanical damage.

[0097] Figure 2 The second embodiment of the radiation-proof and impact-proof radioactive waste container is shown, wherein the radioactive waste storage container 100 and the radioactive waste transport tank 200 are connected to the Figure 1 In fact, the common features of radioactive waste storage tanks will have Figure 1 The same or corresponding features in the present invention are marked with a reference numeral increased by 100. The reference numerals related to the radioactive waste transport container 200 are the same as those in the present invention. Figure 1 The same as in.

[0098] In a second embodiment, the container comprises a single inner vessel 124. The inner vessel 124 is placed in a single compartment 152 of an inner shelf 150. The inner vessel 124 is made of stainless steel. The inner vessel 124 with its cap 128 has a height between 500 mm and 1000 mm, and a capacity between 50 L and 350 L.

[0099] Waste 126 shown in the inner vessel 124 is slightly radioactive. For example, waste includes metal structures of fuel elements resulting from reactor operation, used gloves, protective clothing, irradiated tools, shells, connectors, radioactive mining residues (which may cause chemical toxicity problems if uranium is present together with other additional toxic products such as lead, arsenic, mercury, etc.), radioactive waste from the medical sector, and those whose half-life is less than 100 days.

[0100] In the embodiment of the invention presented here, the container 100 also includes a plastic layer 190, preferably a low-density or high-density polymer, which covers the radioactive waste in the inner vessel 124. The plastic can be pre-liquefied and then mixed with the load, and / or the plastic can come from several low / high-density polymers. Suitable plastic materials can include materials such as polyethylene (PE, such as LDPE, HDPE, UHMWPE, etc.) or thermoplastic natural rubber of a high-density polyethylene / natural rubber (HDPE / NR) mixture, preferably a boronized or boron carbide-containing material.

[0101] Reference numerals:

[0102] 10.100 Radioactive waste storage container

[0103] 12, 112 stainless steel outer wall

[0104] 14, 114 stainless steel inner wall

[0105] 16, 116 low carbon steel layer

[0106] 18, 118 stainless steel bottom

[0107] 19, 119 ring

[0108] 20, 120 stainless steel cover

[0109] 22, 122 A certain volume of quartz sand

[0110] 241, 242, 124 Internal radioactive waste containers

[0111] 26, 126 Radioactive waste

[0112] 281, 282, 128 Removable cap

[0113] 301, 302, 130 Clamping parts

[0114] 40, 140 pressure relief valve

[0115] 50, 150 Shelves

[0116] 521, 522, 152 Shelf compartments

[0117] 53, 153 Continuous lead lining

[0118] 54, 154 stainless steel top

[0119] 54', 154' stainless steel top lead layer

[0120] 56, 156 Beaker-shaped stainless steel enclosure

[0121] 58 Middle wall of shelf

[0122] 80, 180 external enclosure

[0123] 190 Plastic layer

[0124] 200 External (radioactive waste) transport tank

[0125] 212 Tank body outer layer

[0126] 214 Tank body inner layer

[0127] 216 tank body middle layer

[0128] 222 Tank bottom outer layer

[0129] 224 Tank bottom inner layer

[0130] 226 tank bottom middle layer

[0131] 228 Welding parts

[0132] 232 Tank cover outer layer

[0133] 234 Tank cover inner layer

[0134] 236 Tank cover intermediate layer

[0135] 238 Eyelets

[0136] 239 Thread

[0137] 240 Positioning block

[0138] 250 voids (preferably filled with quartz sand).

Claims

1. A radiation-proof and impact-proof radioactive waste container, the radiation-proof and impact-proof radioactive waste container comprising: A radioactive waste storage container (10, 100) defines an inner space having a radiation-proof cylindrical or polygonal cavity, the radioactive waste storage container (10, 100) comprising: - an outer wall (12, 112) made of stainless steel facing outwards; - an inner wall (14, 114) made of stainless steel facing the inner space; - a low carbon steel layer (16, 116) between the stainless steel inner wall and the stainless steel outer wall; - a bottom portion (18, 118) made of stainless steel; - a continuous lead lining (53, 153) which covers the stainless steel inner wall (14, 114) and the stainless steel bottom (18, 118) on the side of the stainless steel inner wall (14, 114) and the stainless steel bottom (18, 118) facing the inner space and is separated from the radiation-proof cylindrical or polygonal cavity by a beaker-shaped stainless steel enclosure (56, 156); - a stainless steel top (54, 154) comprising a lead layer (54', 154'), the stainless steel top (54, 154) being configured to enclose the radiation-protected cylindrical or polygonal cavity; - one or more internal radioactive waste containers (241, 242, 124), the internal radioactive waste containers (241, 242, 124) being configured to contain radioactive waste (26, 126), and the internal radioactive waste containers (241, 242, 124) being placed within the radiation-proof cylindrical or polygonal cavity; - a volume of quartz sand (22, 122) which at least partially fills the space of the radiation-proof cylindrical or polygonal cavity remaining vacant after the one or more internal radioactive waste vessels (241, 242, 124) are inserted; and - a stainless steel cover (20, 120) which is attached to the radioactive waste storage container (10, 100) and hermetically closes the radioactive waste storage container (10, 100).

2. The radiation-proof and impact-proof radioactive waste container according to claim 1, wherein: The radioactive waste storage container (10, 110) comprises a pressure relief valve (40, 140).

3. The radiation-proof and impact-proof radioactive waste container according to claim 1 or 2, wherein: The one or more inner vessels (241, 242, 124) include an attached removable cap (281, 282, 128), and both the inner vessel (241, 242, 124) and the cap (281, 282, 128) are made of ceramic, wherein, preferably, the cap is attached to the vessel by a removable clamp (301, 302, 130).

4. A radiation-proof and impact-proof radioactive waste container according to one of the preceding claims, the radiation-proof and impact-proof radioactive waste container comprising an internal shelf (50, 150), the internal shelf (50, 150) comprising one or more shelf compartments (521, 522, 152), and the one or more vessels (241, 242, 124) are arranged in the internal shelf (50, 150).

5. The radiation-proof and impact-proof radioactive waste container according to one of the preceding claims, wherein: The stainless steel of the inner wall and / or the stainless steel of the outer wall is austenitic stainless steel or martensitic stainless steel. Preferably, the stainless steel of the inner wall and / or the stainless steel of the outer wall is 316L / EN1.4404 stainless steel. Preferably, the stainless steel of the inner wall and / or the stainless steel of the outer wall is 410 or 420 / EN1.4021 stainless steel.

6. The radiation-proof and impact-proof radioactive waste container according to one of the preceding claims, further comprising a rubber outer shell (80, 180) covering at least a portion of the stainless steel outer wall (12, 112) of the radioactive waste storage container (10, 100).

7. The radiation-proof and impact-proof radioactive waste container according to one of the preceding claims, further comprising a removable outer transport tank (200), wherein: The removable outer transport tank (200) comprises a hollow cylindrical or polygonal body having a lower end and an upper end, the hollow cylindrical or polygonal body being configured for fittingly receiving the radioactive waste storage container (10, 100) therein, wherein the lower end is closed by a fixed bottom and the upper end is closed by a removable tank cover, wherein the hollow cylindrical or polygonal body, the fixed bottom and the removable tank cover are composed of at least three layers: an outer layer (212, 222, 232) made of armor grade steel, preferably the outer layer (212, 222, 232) having a thickness of at least 15 m m thickness; an inner layer (214, 224, 234) made of high-strength steel, preferably, the inner layer (214, 224, 234) has a thickness of at least 35 mm; and an intermediate layer (216, 226, 236) between the outer layer (212, 222, 232) and the inner layer (214, 224, 234), preferably, the intermediate layer (216, 226, 236) has a thickness of at least 25 mm, the intermediate layer (216, 226, 236) is made of one or more layers, the layer bodies include ceramic materials or consist of ceramic materials, wherein the ceramic materials are selected from oxide ceramics, non-oxide ceramics and mixtures thereof.

8. The radiation-proof and impact-proof radioactive waste container according to claim 7, wherein: The hollow cylindrical or polygonal body of the removable outer transport tank (200) and any voids (250) within the radioactive waste storage container (10, 100) are at least partially filled with quartz sand.

9. The radiation-proof and impact-proof radioactive waste container according to claim 7 or 8, wherein: The armor grade steel of the outer layer (212, 222, 232) has a Brinell hardness HBW of at least 3900 MPa according to ISO 6506-1:2014.

10. The radiation-proof and impact-proof radioactive waste container according to any one of claims 7 to 9, wherein: The high-strength steel of the inner layer (214, 224, 234) has a Brinell hardness HBW between 2450 MPa and 3675 MPa according to ISO 6506-1:2014 standard.

11. The radiation-proof and impact-proof radioactive waste container according to any one of claims 7 to 10, wherein: The intermediate layer (216, 226, 236) comprises two or more layers and a tough fiber reinforced layer or a metal layer backing, wherein the layers comprise or consist of a ceramic material, preferably, the tough fiber is a para-aramid fiber.

12. A use of an external radioactive waste transport tank (200) for further temporarily protecting a radioactive waste storage container as defined in any one of claims 1 to 6 from mechanical damage during its transportation and storage, in particular, the use of the external radioactive waste transport tank (200) for further temporarily protecting a radioactive waste storage container as defined in any one of claims 1 to 6 from impact damage caused by accidents or projectiles during its transportation and storage, wherein: The radioactive waste transport tank (200) comprises a hollow cylindrical or polygonal body having a lower end and an upper end, the hollow cylindrical or polygonal body being configured to receive the radioactive waste storage container (10, 100) in an adaptive manner in the hollow cylindrical or polygonal body, wherein the lower end is closed by a fixed bottom, and the upper part is closed by a removable tank cover, wherein the hollow cylindrical or polygonal body, the fixed bottom and the removable tank cover are composed of at least three layers: an outer layer (212, 222, 232) made of armor grade steel, preferably, the outer layer (212, 222, 232) has having a thickness of at least 15 mm; an inner layer (214, 224, 234) made of high-strength steel, preferably, the inner layer (214, 224, 234) has a thickness of at least 35 mm; and an intermediate layer (216, 226, 236) between the outer layer (212, 222, 232) and the inner layer (214, 224, 234), preferably, the intermediate layer (216, 226, 236) has a thickness of at least 25 mm, the intermediate layer being made of one or more layer bodies, the layer bodies comprising ceramic material or consisting of ceramic material, wherein the ceramic material is selected from oxide ceramics, non-oxide ceramics and mixtures thereof.

13. A method for further temporarily protecting a radioactive waste storage container as defined in any one of claims 1 to 6 from mechanical damage during its transportation and storage to provide a radiation-proof and impact-proof radioactive waste container, the method comprising: - providing an external transport tank, the external transport tank comprising a hollow cylindrical or polygonal body having a lower end and an upper end, the hollow cylindrical or polygonal body being configured for fittingly receiving the radioactive waste storage container in the hollow cylindrical or polygonal body, wherein the lower end is closed by a fixed bottom and the upper part is closed by a removable tank cover, wherein the hollow cylindrical or polygonal body, the fixed bottom and the removable tank cover are composed of at least three layers: an outer layer made of armor-grade steel, preferably, the outer layer has a thickness of at least 15 mm; an inner layer made of high-strength steel, preferably, the inner layer has a thickness of at least 35 mm; and an intermediate layer between the outer layer and the inner layer, preferably, the intermediate layer has a thickness of at least 25 mm, wherein the intermediate layer is made of one or more layer bodies, the layer bodies comprising or consisting of ceramic material, wherein the ceramic material is selected from oxide ceramics, non-oxide ceramics and mixtures thereof; - placing the radioactive waste storage container in the radioactive waste transport tank; - optionally filling any remaining voids within the radioactive waste transport tank with quartz sand; and - Sealing the radioactive waste transport canister by securely closing the canister cover.

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