Procedure and arrangement for the processing of radioactive waste

Abstract

Method for the treatment of radioactive waste embedded in an organic matrix in the form of bitumen, epoxy resin, urea resin or an inorganic matrix in the form of cement by means of pyrolysis, comprising the process steps: - Introducing the radioactive waste contained in a receptacle (18, 28) into a reaction chamber (40) in which a water vapor-containing atmosphere of a temperature T with T ≥ 200 °C is or will be established, - Carrying out the pyrolysis, - Removal of gases (exhaust gas) from the reaction chamber, - Removal of the sample from the reaction chamber, in addition, at least one procedural step from the group is carried out: - Introducing oxygen and / or CO2 into the reaction chamber (40) during pyrolysis, in substoichiometric or maximally stoichiometric amounts, - Adjusting the amount of water vapor to be introduced into the reaction chamber (40) depending on the oxidizable substance in the exhaust gas, - Adjusting the amount of oxygen and / or CO2 to be introduced into the reaction chamber (40) depending on the oxidizable substance in the exhaust gas, - Switching off pyrolysis depending on the amount of oxidizable substance present in the exhaust gas, - targeted introduction of water vapor and / or oxygen and / or CO2 into or near the radioactive waste, - controlled guidance of water vapor and / or oxygen and / or CO2 within the reaction space (40).

Description

[0001] The invention relates to a method for processing radioactive waste stored in an organic matrix in the form of bitumen, epoxy resin, urea resin, or an inorganic matrix in the form of cement. The invention also relates to an arrangement for processing radioactive waste stored in an organic matrix in the form of bitumen, epoxy resin, urea resin, or an inorganic matrix in the form of cement.

[0002] In nuclear technology, such as nuclear power plants or other workplaces using radioactive materials, inorganic and organic radioactively contaminated waste is generated that requires disposal. This includes, for example, ion exchange resins, evaporator concentrates, sludge, metallic components, rubber, plastic, and even clothing.

[0003] For the disposal of radioactively contaminated waste, it is usually placed in a container in which the radioactive waste is surrounded by a matrix, i.e., embedded in it. In the past, it was assumed that using bitumen as a matrix would allow for trouble-free final disposal.

[0004] It is also possible to mix waste and bitumen externally, e.g. with an extruder, and then fill them into barrels.

[0005] Bitumen is also used when the waste is not stored in barrels, but in containers or chambers, so-called compartments.

[0006] Examinations of drums have now revealed that, contrary to expectations, waste materials are being decomposed by radiolysis, so that the resulting gas causes the drums to bulge and possibly burst due to a rise in pressure. Therefore, appropriately embedded radioactive waste must be processed. For this purpose, a known method is to carry out processing using pyrolysis and steam, known as hydropyrolysis. This involves pyrolyzing (i.e., gasifying) the bitumen, organic components, and nitrates in a furnace, i.e., a reaction chamber, and then feeding the exhaust gas to post-combustion.

[0007] DE 26 41 264 A1 relates to a process for the disposal of radioactive organic waste by pyrohydrolytic incineration. The products to be pyrohydrolyzed are transported through a furnace using trays. Steam is circulated through a closed pipe system. The steam treatment takes place in the closed furnace at a temperature between 600 °C and 1100 °C.

[0008] The subject of DE 600 24 306 T2 is a process for treating radioactive graphite by reaction at a temperature above 350 °C with superheated steam or gases containing water vapor.

[0009] DE 28 19 059 A1 describes a furnace for incinerating nuclear fission and fertile waste. Superheated steam is used as the reaction gas for pyrohydrolysis.

[0010] DE 26 28 169 A1 discloses a method and device for converting radioactive ion exchange resins into a storable form. This involves thermal decomposition below the evaporation or sublimation temperature of the bound contaminants, with a temperature not exceeding 500 °C.

[0011] The subject of US 2008 / 0 039 674 A1 is a process for processing hazardous waste stored in drums. Pyrolysis is used to evaporate the organic substances present in the drums. The resulting gases are then removed by means of a purge gas stream passing through a pyrolysis chamber and fed into a steam reformer.

[0012] US Pat. No. 6,280,694 B1 relates to a single-stage process for removing NOx compounds from, in particular, radioactive waste products. This process uses a reactor divided into several zones. According to one embodiment, oxidizing conditions prevail in a lowermost zone through the addition of superheated steam with oxygen, strongly reducing conditions prevail in a middle zone, and oxidizing conditions prevail in an upper zone.

[0013] The subject of US 4 628 837 A is a process for the treatment of spent ion exchange resins comprising a first step in which the spent ion exchange resin is pyrolyzed in an inert gas atmosphere and a decomposition gas generated during the first pyrolysis is separated, and a second step in which the spent ion exchange resin which has undergone the first step is pyrolyzed in an oxidizing atmosphere and a decomposition gas generated in the second pyrolysis step is separated.

[0014] However, known methods have the disadvantage that corresponding hydropyrolysis takes a relatively long time to remove all the organic embedding material as well as the organic components of the radioactive waste.

[0015] It is therefore an object of the present invention to provide a method for processing radioactive waste stored in a matrix by means of pyrolysis, comprising the process steps - introducing the radioactive waste contained in a receptacle into a reaction chamber in which a water vapor-containing atmosphere with a temperature T with T ≥ 200 °C is or will be established, - Carrying out pyrolysis, - Removal of gases (exhaust gas) from the reaction chamber, - Removal of the recordings from the reaction chamber, in such a way that an extremely effective pyrohydrolysis can be carried out.

[0016] To solve the problem, it is proposed that at least one additional process step from the group is carried out: - Introducing oxygen and / or CO2 into the reaction chamber during pyrolysis, preferably in substoichiometric, if necessary up to maximum stoichiometric, quantities, - Adjusting the water vapor to be introduced into the reaction chamber depending on the oxidizable substance in the exhaust gas, - Adjusting the oxygen and / or CO2 to be introduced into the reaction chamber depending on the oxidizable substance in the exhaust gas, - Switching off pyrolysis depending on the oxidizable substance present in the exhaust gas, - deliberate introduction of water vapor and / or oxygen and / or carbon dioxide into the radioactive waste or in the vicinity of it, - targeted flow of water vapor and / or oxygen and / or carbon dioxide within the reaction chamber.

[0017] According to the invention, one or more additional measures are provided during pyrohydrolysis to gasify volatilizing radioactive waste and organic embedding material. In particular, oxygen and / or CO2 are introduced into the reaction chamber during pyrolysis, with the oxygen content preferably being substoichiometric, optionally up to maximally stoichiometric.

[0018] It is possible to adjust the water vapor to be introduced, which should have a temperature corresponding to that in the reaction chamber, depending on the oxidizable substance in the exhaust gas (pyrolysis gas). This enables a control process.

[0019] A corresponding regulation can also be made for the proportion of oxygen and / or CO2 to be introduced.

[0020] In order to exclude any danger, particularly from explosion, it may also or alternatively be provided that the pyrolysis is switched off depending on the oxidizable substance present in the exhaust gas.

[0021] In particular, it can be provided that the superheated steam or superheated steam with O2 and / or CO2 is directed to the areas in the reaction chamber, i.e., the interior of the furnace, where the radioactive waste is located. In particular, it is provided that, if the waste is located in a container, such as a standard drum, steam is introduced directly into the container, preferably via the holes made for perforating the containers before they are introduced into the reaction chamber, or via another opening made in the container wall, or, for example, via the opening of the lidless container.

[0022] Furthermore, the steam can be circulated in a targeted manner within the reaction chamber, generating a volume flow that is several times higher than the feed.

[0023] The invention is also characterized by the fact that the atmosphere in the reaction chamber is swirled by one or more fans. The fan(s) can be set in rotational motion within the reaction chamber by the introduced gaseous fluid, such as water vapor and / or O2 and / or CO2.

[0024] In particular, it is envisaged that radioactive waste embedded in an organic matrix, such as bitumen, epoxy resin, urea resin, will be processed.

[0025] It is also possible to treat waste in an inorganic matrix, such as cement. While this does not involve complete pyrolysis, i.e., gasification of the matrix, the waste becomes inert due to the pyrolysis.

[0026] The invention is, of course, not limited by the fact that the radioactive waste was homogeneously mixed with bitumen. Heterogeneous storage in a matrix is ​​also possible. This applies in particular to metals, building materials, animal carcasses, or glass that are coated with a matrix material such as bitumen.

[0027] In particular, if the radioactive material with the matrix is ​​filled into a container such as a standard drum, such as a 200 l drum, parts of larger storage units, so-called compartments, which are arranged on suitable supports in the reaction chamber, can also be pyrolyzed.

[0028] It is also possible to melt and remove at least part of the matrix before pyrolysis, which is then burned separately.

[0029] Irrespective of this, it is intended that when barrels are used, they are perforated before being placed in the reaction chamber.

[0030] The containers containing the embedded radioactive waste are typically first placed in a shielded loading room, where manipulators remove the container lid and perforate the peripheral wall. For this purpose, the containers are placed on carriers, which transport the containers through the loading room, the subsequent reaction chamber (furnace), and then into a downstream sorting room. The carriers can then be reused.

[0031] The supports, which have a tub geometry, are dimensionally designed in such a way that the entire contents of the containers or barrels can be accommodated.

[0032] Within the reaction chamber, a temperature is set, particularly in the range between 200 °C and preferably up to 800 °C. Superheated steam is then supplied to the chamber.

[0033] According to the invention, additional oxygen and / or CO2 can be added to the reaction chamber. The oxygen content is preferably substoichiometric, optionally up to maximum stoichiometric.

[0034] To ensure that pyrolysis is targeted at the radioactive waste area, an inventive proposal is proposed for the gaseous fluid, such as water vapor and / or O2 and / or CO2, to be directed in a targeted manner within the reaction chamber. For this purpose, so-called steam jets can be used, which are designed as nozzles through which the water vapor is introduced into the reaction chamber. The nozzles simultaneously draw in atmosphere from the reaction chamber, creating an internal circulation and thus a volume flow that corresponds several times to the feed.

[0035] The nozzles work like Venturi nozzles.

[0036] In addition or alternatively, it is possible to introduce steam or steam plus O2 and / or CO2 directly into the containers via nozzles or spray heads, i.e., where the radioactive waste is located. For this purpose, rod elements such as lances can be used. These have a nozzle or spray head at the end that releases the gaseous fluid and is inserted through an opening in a drum.

[0037] Of course, there are other ways to circulate and mix the atmosphere within the reaction chamber. Fans powered by the steam itself could even be used.

[0038] An exhaust line leads from the reaction chamber to an afterburner. Before the exhaust gas enters the afterburner, the proportion of oxidizable substances is determined. The higher the proportion, the higher the proportion of organic substances that have not yet been pyrolyzed. This can be determined, for example, by determining the heat of reaction during the oxidation of the exhaust gas. Depending on the proportion of organic substances, the water vapor supply, the temperature in the reaction chamber, or the oxygen or CO2 supply can then be regulated.

[0039] In the afterburner itself, the exhaust gas is mixed with air and burned. After exiting the afterburner, the oxygen content is measured. This should be kept at a constant value, such as 5% to 7%, especially 6%. In order to maintain a constant oxygen content of the gas emerging from the afterburner, the air supplied to the afterburner is regulated accordingly. According to the invention, the temperature and / or the amount of water vapor supplied and / or the oxygen or CO2 supplied to the reaction chamber, i.e., the interior of the furnace, is regulated depending on the air supplied, or even shut down, for example, to prevent the risk of an explosion.

[0040] The amount of air supplied to the afterburner is a measure of the combustible component present in the pyrolysis gas, such as organic matter, H2, CO.

[0041] The invention is therefore characterized by a method for controlling the water vapor and / or O2 and / or CO2 to be supplied to the reaction chamber and / or temperature in the reaction chamber by determining the air to be supplied to the afterburner, wherein the oxygen of the gas taken from the afterburner is kept constant or almost constant.

[0042] The invention is also characterized by a method for controlling water vapor and / or O2 and / or CO2 to be supplied to the reaction chamber and / or temperature in the reaction chamber by determining combustible substance contained in the pyrolysis gas.

[0043] In particular, the invention is characterized by its own inventiveness in that the control of the gaseous fluid to be supplied to the reaction chamber is carried out redundantly and diversely, i.e. on the one hand depending on the air to be supplied to the afterburner and on the other hand on the oxygen content in the pyrolysis gas.

[0044] Gaseous fluid includes water vapor and / or O2 and / or CO2, whereby CO2 can be used instead of water vapor if necessary.

[0045] The invention is also characterized by the fact that radioactive waste embedded in an organic matrix, such as bitumen, epoxy resin, urea resin, is processed.

[0046] Alternatively, it is planned to process radioactive organic waste embedded in an inorganic matrix, such as cement.

[0047] In particular, the invention provides that radioactive waste is introduced into an open container, in particular one having perforations on the circumference, such as a container, in particular a 200 1 standard drum, wherein water vapor is introduced directly into the area of ​​the radioactive waste by means of a rod element, such as a lance, passing through an opening and having a spray head or a nozzle.

[0048] Another possibility is that gaseous fluid such as at least water vapor is introduced into the reaction chamber via a nozzle that sucks in atmosphere from the reaction chamber, such as a Venturi nozzle.

[0049] Additionally or alternatively, it is provided that gaseous fluid such as at least water vapor is guided within the reaction chamber in such a way that radioactive waste or the matrix is ​​specifically exposed to water vapor.

[0050] In particular, the invention is also characterized in that the exhaust gas is fed to an afterburner, wherein before the afterburner of the exhaust gas, its oxidizable portion is determined and, depending on the oxidizable portion, the supply of gaseous fluid such as water vapor and / or oxygen and / or CO2 supply to the reaction chamber and / or temperature in the reaction chamber is regulated, wherein the regulation also includes a shutdown of the pyrolysis.

[0051] Alternatively or additionally, it is provided in particular that the post-combustion is carried out in a post-combustion chamber to which the exhaust gas and air are supplied, and that the air supply is regulated as a function of the oxygen contained in the gas emerging from the post-combustion chamber and the water vapor supply and / or oxygen and / or CO2 supply to the reaction chamber and / or the temperature in the reaction chamber is regulated as a function of the air supply, wherein the control also includes switching off the pyrolysis.

[0052] The invention is particularly also characterized by an arrangement for processing radioactive waste stored in a matrix, comprising a reaction chamber for carrying out a pyrolysis, wherein an atmosphere and a temperature T with T ≥ 200 °C, in particular T > 400 °C, preferably 400 °C < T < 800 °C, can be set in the reaction chamber and wherein a loading chamber is arranged upstream of the reaction chamber and a sorting chamber is arranged downstream, wherein at least one device is provided in the reaction chamber via which the atmosphere within the reaction chamber can be circulated or atmosphere can be supplied to the radioactive waste in a targeted manner.

[0053] The atmosphere is, in particular, a water vapor atmosphere, to which oxygen and / or carbon dioxide may be added if necessary.

[0054] Alternatively, however, there is also the possibility that the water vapor is replaced by CO2.

[0055] For the sake of simplicity, we will generally refer to water vapor below, although - as previously explained - other gaseous fluids can also form the atmosphere.

[0056] The device can be a nozzle through which water vapor can be supplied from outside the reaction chamber while simultaneously drawing in water vapor from the atmosphere. The Venturi principle is used.

[0057] Alternatively, the device may be a rod body, such as a lance, with a nozzle and / or spray head, through which the radioactive waste is subjected to steam in a directed manner.

[0058] It is also possible to mix or swirl the atmosphere in the reaction chamber using one or more fans.

[0059] The invention is also characterized in that the reaction chamber has a connection for supplying oxygen and / or carbon dioxide to the reaction chamber, preferably in substoichiometric, optionally up to maximally stoichiometric, quantities. This connection can be the one through which steam is supplied to the reaction chamber.

[0060] It is also possible for the reaction chamber to be connected to an exhaust gas combustion chamber, upstream of which a measuring device for determining oxidizable components in the exhaust gas is arranged and / or downstream of which a measuring device for determining oxygen contained in gas escaping from the afterburning chamber is arranged, wherein the measuring device controls the amount of air to be supplied to the afterburning chamber, which in turn is the controlled variable for the gaseous fluid to be supplied to the reaction chamber and / or the temperature to be set in the reaction chamber.

[0061] Further details, advantages and features of the invention emerge not only from the claims and the features derived therefrom - individually and / or in combination - but also from the following description of preferred embodiments derived from the drawings.

[0062] They show: Fig. 1 a schematic diagram of an arrangement for the processing of radioactive waste, Fig. 2 a first embodiment for supplying steam into a reaction chamber, Fig. 3 a second embodiment of a water vapor supply into a reaction chamber, Fig. 4 a third embodiment of a water vapor supply into a reaction chamber, Fig. 5 a fourth embodiment of a water vapor supply into a reaction chamber, Fig. 6 a fifth embodiment of a water vapor supply into a reaction chamber, Fig. 7 a first control loop and Fig. 8 a second control loop.

[0063] In Fig. Figure 1 shows, purely in principle, a plant or arrangement 10 for processing radioactive waste stored in a matrix by means of pyrolysis. The invention is described using hydropyrolysis, i.e., pyrolysis with steam. However, CO2 can also be used instead of steam. For the sake of simplicity, however, the term steam will be used below, although steam can also be understood as a synonym for CO2.

[0064] The arrangement 10 comprises a furnace 12 providing a reaction chamber 40 in which the hydropyrolysis is carried out. The furnace 12 is heated to a temperature preferably between 400°C and 800°C. Superheated steam is then introduced into the furnace 12 via the feed lines described below. Upon introduction, the steam should have a temperature that corresponds to that inside the furnace. A loading chamber 14 is arranged upstream of the pyrolysis furnace 12, and a sorting chamber 16 is arranged downstream, both of which are shielded.

[0065] In particular, the furnace 12 is designed such that hydropyrolysis can be carried out at least simultaneously for at least four barrels 18.

[0066] In the exemplary embodiment, the radioactive waste to be processed is embedded in a matrix located in drums 18, without this limiting the teachings of the invention. Other organic matrix materials or even inorganic matrix materials are also possible. The appropriately filled drums 18 are positioned on trough-shaped supports 22 in an anteroom 20, and are then perforated in the loading area by means of manipulators 24, 26. The upper lid is also removed.

[0067] Correspondingly opened and perforated containers 28 are then transported by means of a conveyor through the loading chamber 14 into the interior 40 of the furnace 12, i.e. into the reaction chamber in which the hydropyrolysis is carried out.

[0068] If necessary, it is also possible to melt the matrix beforehand and then convey the container into furnace 12. The molten matrix material is burned separately.

[0069] Above the furnace 12 is a steam supply line 30, from which lines 32, 34, 36, 38 extend, through which the steam is fed into the furnace interior 40, possibly via fans 33, 35, 37, 39. Furthermore, an exhaust line 42 extends from the furnace 12, through which the pyrolysis gas is fed to a post-combustion unit.

[0070] It is important that the steam reaches close to the radioactive waste so that the organic components can be pyrolyzed, i.e., gasified. These are organic components such as salts of organic acids, complexing agents, ion exchange resins, etc. The inorganic components, with the exception of nitrates, do not react. Inorganic inert materials include solids from evaporator concentrates, phosphates, sulfates, or borates of sodium, calcium, etc.

[0071] In order to ensure that the steam reaches the waste to be gasified sufficiently close, measures are planned in particular to ensure that Fig. 2 and Fig. 4 can be found.

[0072] Thus, it is possible to introduce water vapor directly into the interior of the container 28, e.g. through an opening of the perforation, via a lance 44 or an equivalent element having a nozzle or a spray head 46 at its free end, as is the case with the Fig. 2 can be seen.

[0073] According to the example of Fig. 4, a corresponding lance is guided through the opening of the container 28, which has been freed from a lid, into the interior of the container, so that water vapor is released immediately.

[0074] The Fig. Figure 5 shows a measure in which the steam is guided through openings 48, 49 into the interior 40 of the furnace 12 and is discharged into the furnace 12 itself through nozzles 50, 51, which function roughly like a Venturi nozzle, i.e., the steam flowing through the nozzles 50, 51 draws in atmosphere from the interior 40 of the furnace 12, creating a circuit indicated by the arrows 52. Thus, a large quantity of steam reaches the immediate area of ​​the perforated and open containers 28, allowing for optimal pyrolysis.

[0075] The invention is of course not abandoned even if steam is introduced into the interior 40 of the furnace 12 via openings 54, 56 in the usual way. Fan gates 33, 37 can be used for support ( Fig. 3).

[0076] According to Fig. 6, the atmosphere present in the furnace 12 can be swirled by means of one or more fans 70. The fan(s) 70 are set in rotational motion in the furnace 12 by steam introduced, for example, through an opening 72.

[0077] Furthermore, it is possible to introduce oxygen or CO2 into the interior 40 (reaction chamber) of the furnace 12 via a connection not shown or via the connection through which steam is introduced into the chamber 40. The oxygen content is preferably substoichiometric to avoid the risk of burning or explosion.

[0078] Based on the Fig. 7 and Fig. 8 explains control circuits for adjusting or regulating the amount of water vapor and / or oxygen and / or carbon dioxide to be supplied to the interior space 40 or the temperature in the reaction space 10.

[0079] So in Fig.8 shows the furnace 12 in principle, which is connected via the exhaust gas line 42 to a post-combustion chamber 74, to which air is supplied via a line 76.

[0080] The oxygen content of the gas leaving the post-combustion chamber 74 (line 78) is determined by a first measuring device 80, with the air supply line 76 being adjusted such that the oxygen content of the outflowing gas is constant or nearly constant. The oxygen content should be approximately 6%. Depending on the amount of air supplied to the post-combustion chamber 74, the amount of gaseous fluid, i.e., water vapor, supplied to the furnace 12 is regulated, whereby the proportion of O2 and CO2 can also be regulated. This is illustrated by connection 84.

[0081] A further measuring device 86 is provided in the pyrolysis exhaust line 42 leading to the post-combustion chamber 74. It can be used, for example, to determine the proportion of oxidizable components in the pyrolysis gas using a sensor that measures the heat of reaction during oxidation. This proportion can also be used as a control variable (connection 88) for the water vapor and / or oxygen and / or CO2 to be supplied to the furnace 12 and / or for setting the temperature in the furnace 12.

[0082] In particular, both the amount of air to be supplied to the afterburning chamber 74 and the proportion of oxidizable components contained in the pyrolysis gas are used as control variables, so that redundant diverse control is possible.

[0083] Such adjustment or regulation can also be made depending on the air supplied to the afterburner.

[0084] After pyrolysis has been completed, the furnace 12 is cooled, and the drums are then conveyed to the sorting room 16, where the remaining inorganic components are sorted and the drums are cut into pieces using manipulators 60, 62. The components are transferred to containers 64, 66, 68 according to the determined radioactivity, which are then disposed of according to the respective regulations.

[0085] The trough-shaped supports 22 are returned via a conveyor device 70 to the loading space 14 for receiving new barrels 18, as can be seen from the illustration.

[0086] The invention also covers the use of CO2 for pyrolysis instead of steam.

Claims

[1] Process for the treatment of radioactive waste embedded in an organic matrix in the form of bitumen, epoxy resin, urea resin or an inorganic matrix in the form of cement by means of pyrolysis, comprising the process steps: - introducing the radioactive waste located in a receptacle (18, 28) into a reaction chamber (40) in which a water vapor-containing atmosphere of a temperature T with T ≥ 200 °C is or will be set, - Carrying out pyrolysis, - Removal of gases (exhaust gas) from the reaction chamber, - Removing the recording from the reaction chamber, In addition, at least one process step from the group is carried out: - introducing oxygen and / or CO2 into the reaction chamber (40) during pyrolysis, in substoichiometric or maximum stoichiometric quantities, - adjusting the water vapor to be introduced into the reaction chamber (40) depending on the oxidizable substance in the exhaust gas, - adjusting the oxygen and / or CO2 to be introduced into the reaction chamber (40) depending on the oxidizable substance in the exhaust gas, - Switching off pyrolysis depending on the oxidizable substance present in the exhaust gas, - targeted injection of water vapor and / or oxygen and / or CO2 into the radioactive waste or in the vicinity of it, - targeted supply of water vapor and / or oxygen and / or CO2 within the reaction chamber (40). [2] Method according to claim 1, characterized bythat radioactive waste is introduced into an open container, in particular into a container having perforations as the receptacle, such as a container (28), in particular a 200 l standard drum, wherein at least water vapor, optionally additionally O2 and / or CO2, is introduced into the radioactive waste via a rod element (44) passing through an opening and having a spray head or a nozzle, such as a lance. [3] Method according to claim 1 or 2, characterized by that water vapor is introduced into the reaction chamber (40) via a nozzle (50) which sucks in an atmosphere from the reaction chamber, such as a Venturi nozzle. [4] Method according to at least one of the preceding claims, characterized by that the atmosphere in the interior space (40) is mixed by means of at least one fan (70) driven by the water vapor supplied to the interior space. [5] Method according to at least one of the preceding claims, characterized bythat water vapor is guided within the reaction chamber (40) in such a way that radioactive waste or the matrix is ​​specifically exposed to water vapor. [6] Method according to at least one of the preceding claims, characterized by that the exhaust gas is fed to an afterburner, wherein before the afterburner of the exhaust gas its oxidizable portion is determined and, depending on the oxidizable portion, the water vapor supply and / or oxygen and / or CO2 supply to the reaction chamber (40) and / or the temperature in the reaction chamber is regulated, wherein the regulation includes switching off the pyrolysis. [7] Method according to claim 6, characterized bythat the afterburning is carried out in an afterburning chamber (74) to which the exhaust gas and air are supplied, and that the water vapor supply and / or oxygen and / or CO2 supply to the reaction chamber (40) and / or temperature in the reaction chamber is regulated as a function of the air supplied to the afterburning chamber, wherein the regulation also includes switching off the pyrolysis. [8] Method according to at least claims 6 and 7, characterized by that the control of the water vapor to be supplied to the reaction chamber and / or the O2 and / or CO2 supply and / or the temperature in the reaction chamber is carried out redundantly and diversely. [9] Method according to at least one of claims 1 to 8, characterized by that the water vapor is replaced by CO2. [10] Arrangement (10) for processing radioactive waste embedded in an organic matrix in the form of bitumen, epoxy resin, urea resin or an inorganic matrix in the form of cement, comprising a reaction chamber (40) for carrying out pyrolysis, wherein an atmosphere and a temperature T of ≥ 200 °C, in particular T > 400 °C, preferably 400 °C < T < 800 °C, maximum 950 °C, can be set in the reaction chamber and wherein a loading chamber (14) is arranged upstream of the reaction chamber and a sorting chamber (16) is arranged downstream, wherein at least one device (44, 50) is provided in the reaction chamber (40) via which the atmosphere within the reaction chamber can be circulated and / or gaseous fluid such as water vapor and / or CO2 and / or O2 can be supplied to the radioactive waste in a targeted manner. [11] Arrangement according to claim 10, characterized bythat the device is a nozzle (50) through which gaseous fluid can be supplied from the outside to the reaction chamber (40) while simultaneously sucking in atmosphere from the reaction chamber. [12] Arrangement according to claim 10 or 11, characterized by that the device is a rod body (44), such as a lance, with a nozzle (46) and / or spray head, via which the radioactive waste can be subjected to gaseous fluid in a directed manner. [13] Arrangement according to at least one of claims 10 to 12, characterized by that the gaseous fluids, in particular superheated steam, can be fed to the reaction chamber (40) via a connection, wherein carbon dioxide and / or oxygen can be fed in a substoichiometric to a maximum stoichiometric amount via the connection or at least one further connection, [14] Arrangement according to at least one of claims 10 to 13, characterized bythat the reaction chamber (40) is connected to a post-combustion chamber (74) via a pyrolysis gas line (42), that the pyrolysis gas line is connected to a first measuring device (86) for determining oxidizable components in the pyrolysis gas and / or that a second line (78) extends from the post-combustion chamber, in which line the oxygen content of the gas discharged from the post-combustion chamber can be measured by means of a second measuring device (80), that the amount of air supplied to the post-combustion chamber can be regulated as a function of the measured oxygen content and that the amount of air and / or the proportion of oxidizable components in the pyrolysis gas is or are the manipulated variable or variables for the gaseous fluid and / or oxygen and / or carbon dioxide to be supplied to the reaction chamber.

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