Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
  • A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
  • A62D3/38—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by oxidation; by combustion
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
  • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
  • G21F9/28—Treating solids
  • G21F9/30—Processing
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/20—Organic substances
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2203/00—Aspects of processes for making harmful chemical substances harmless, or less harmful, by effecting chemical change in the substances
  • A62D2203/10—Apparatus specially adapted for treating harmful chemical agents; Details thereof

Definitions

• the invention relates to a process for the continuous decomposition of solid pollutant materials, e.g. spent radioactive ion exchange resins, which are continuously fed to a reactor room, by oxidation by means of a liquid oxide guarantee.
• solid pollutant materials e.g. spent radioactive ion exchange resins
• ion exchange resins for the treatment of radioactive materials. After use, these resins form a large part of the low and medium contaminated nuclear waste, depending on their radioactive content. Most of the commercially used ion exchange materials are synthetic resins. In view of the growing need for additional hazardous waste absorption capacity and its limited availability, volume and weight-concentrating pretreatment of the used ion exchange resins is necessary and economical before further storage preparation for safe depositing of the waste takes place.
• the object of the invention is to disclose a simplified and effective and economical process for the decomposition for the purpose of volume reduction of spent, radioactively contaminated, ion exchange resin and to provide a device for its simple, safe and reliable implementation under easily controllable temperature and pressure conditions.
• the solution to the problem is that the oxidant is hydrogen peroxide, which is continuously metered into the reactor chamber after introduction of a starting energy, and that the resulting residual liquid is continuously removed in a final container that the decomposition of the solid pollutant materials in a temperature range between 100 C. C and 140 ° C takes place, the introduction of the starting energy and the Oxydentien-Dosage controlled or regulated so that this temperature range is reached quickly and then maintained.
• the oxidant is hydrogen peroxide, which is continuously metered into the reactor chamber after introduction of a starting energy, and that the resulting residual liquid is continuously removed in a final container that the decomposition of the solid pollutant materials in a temperature range between 100 C. C and 140 ° C takes place, the introduction of the starting energy and the Oxydentien-Dosage controlled or regulated so that this temperature range is reached quickly and then maintained.
• the reaction temperature is maintained at a level between 105 ° C and 135 ⁇ C depending on the desired decomposition speed of the system dimensions, the foam level and the predetermined amount of feed of the reactants and of the residual solution dosage.
• the advantages of the invention are, in particular, that the operating costs, the construction costs and the maintenance costs of a system required therefor are low and the exhaust gas can be treated quite simply in a closed dispensing treatment device.
• a process control is advantageously provided in which the oxidizing agent is used so sparingly that there is only decomposition but no complete oxidation of the ion exchange resin.
• Fig. 1 shows a decomposition device, schematically, with a vertical section of the reactor.
• Fig. 2 shows a detail section with replaceable filter.
• Fig. 1 shows the functionally essential modules and a reactor schematically; its dimensions and dimensional relationships are typical but changeable, whereby the function is not impaired.
• the decomposition device consists of a hopper reactor (1) which is surrounded by an outer protective jacket (2).
• a hydrogen peroxide tank
• the bottom of the reactor (1) and the protective jacket (2) are releasably connected by a releasable closure (120) to an end container (5) which absorbs both liquid residues during operation and the solid residues after the end of an operating period.
• the bottom end (12) of the reactor (1) is advantageously a filter disk made of sintered glass, which only allows the liquid residues to pass through and only when the solid residues are open can it pass into the end container (5).
• the introduction of catalytic material is provided to start the reaction.
• This is preferably iron sulfate.
• the catalyst (61) is advantageously on a long arm Shovel (6) brought into the reactor (1), namely under the outlet (23) of the oxidizing agent, which is advantageously designed as a nozzle assembly.
• the shovel (6) can be moved to the shovel handle (62) with an adjusting drive (63) to different heights; this influences the course of the reaction.
• the blade handle (62) is designed as a tube which ends at the bottom in the spoon-like recessed blade (6) and at the top carries a funnel attachment or a metering device (64) for introducing the catalyst material.
• the reactor (1) is surrounded directly and on the protective jacket (2) with a thermal insulating jacket (20), so that the decomposition energy released heats up the matrix used to a favorable reaction temperature.
• the process control takes place via one or more temperature measuring probes (7) whose signal or signals are fed to the control device (ST), the metering devices (13, 14, 15), the catalyst feed device (64) and the catalyst adjustment drive (63) controls that a favorable predetermined temperature range is quickly reached in the decomposition reaction and then maintained.
• the exhaust gas is passed through the outlet (11) on the jacket (2) into a cooled condenser (8) and then through a HEPA filter (9).
• the condensate accumulating in the condenser (8) is collected in a receiver (10) and disposed of from there.
• the decomposition process is started with the exothermic decomposition reaction of preferably 60% hydrogen oxide using solid iron sulfate. A physical energy supply is therefore not required, which keeps the device simple.
• the Decomposing hydrogen peroxide attacks the resin used, the decomposition of which follows is also exothermic, so that more heat is released in the reaction medium. This heat collected in the reaction medium decomposes the hydrogen peroxide solution which is fed in and which in turn attacks more ion exchange resin.
• This reaction continues depending on the supply of the two components, which is ultimately limited by the dimensions of the reactor vessel.
• the reaction products are solid residues, liquid solution residues and exhaust gas as well as exhaust steam.
• the solid residues that collect at the bottom of the shaft reactor contain most radioactive substances.
• the cesium, if any, which is highly soluble, is largely contained in the residue liquid.
• the residue liquid, which has been collected in each of the end containers (5), is advantageously returned through the reactor (1) for evaporation so that its volume decreases due to the use of the reactor heat.
• the treatment of the residual liquid depends on its quantity and its level of activity, which in turn depends on the type and composition of the waste that has been decomposed and on the type and quantity of the radioactive substances therein, in the following way:
• the residual liquid has a relatively very low radioactivity, then regardless of its amount, it is directed to the condensate container (10) outside the control zone (17) through a first route of the controllable two-way valve (16).
• the residue liquid has a high specific radioactivity and a large amount is produced, then it is chemically treated in the final container (5) for the purpose of precipitating the radioactive substances and returned via the second way of the two-way valve (16) to the reactor (1), where the precipitates are filtered out. - If the residue liquid has a high specific radioactivity and a large amount is produced, then it is chemically treated in the final container (5) for the purpose of precipitating the radioactive substances and returned via the second way of the two-way valve (16) to the reactor (1), where the precipitates are filtered out. - If the residue liquid has a high specific
• temperature, level and activity sensors (7, N1, N2, A1, A2) are arranged in the reactor (1) and 'in the end container (5), the signals of which are fed to the control device (ST).
• this controls the two-way valve (16) and the supply of the precipitants (F) and the additives (V), which are used for consolidation, into the end container (5) in accordance with predetermined limit values.
• Continuous operation is determined after the catalytic start by the continuous metering of the resin and the controlled supply of the oxidizing agent. If foam is formed, the metering of the reactants is regulated anew when the foam has reached a predetermined level in the reactor.
• the filter closure (12) can be pivoted by the control device (ST) with a controlled drive (12A), so that the solid residues can be emptied each time after the reaction space (1) has been filled a predetermined level and after a subsequent termination of the decomposition reaction and possibly after a precipitation reaction and the completion of the subsequent filtering of the precipitated material, by pivoting the filter closure into the final container.
• a precipitant for example, if radioactive cesium is contained in the residue liquid, concentrated tripotassium ferrohexacyanide is added, as a result of which the cesium is bound and can be filtered out and then compacted and brought into the final container as a solid residue.
• V solidification surcharge for the residues
• water-compatible polyester is suitable, which is brought to the setting in the end container (5).
• the exhaust gas and the exhaust steam are passed through the condenser (8) and then passed through a HEPA filter.
• This stage of the process depends primarily on the decomposition of the organic ion exchange resin. It is advantageously not necessary to carry out a complete oxidation in the zone controlled for radioactivity.
• the concentration of hydrocarbons in the condensate in the condensate container (10) is relatively high, it can be post-oxidized there or later, if necessary, for example also with hydrogen peroxide.
• the supply of hydrogen peroxide is provided with a controllable metering device (D) and an additional heater (H) is built into the condensate container (10).
• This is expediently thermally insulated.
• the resulting decomposition products of post-oxidation, namely carbon dioxide and water vapor leave the container (10) through the exhaust air duct (8A) of the cooler (8) and further through the filter (9).
• the main reactor in the control zone is then not burdened with this side reaction.
• FIG. 2 A section of the device is shown in FIG. 2 with a different, replaceable filter arrangement. It is envisaged that a replacement of the filter disc (12) is possible during operation if such fine residues occur that they clog the filter (12) and pivoting, as is provided in the device according to Fig.1, not is sufficient to clean the filter.
• a horizontal transport path (21) is led into the reactor (1) just above the filter (12) through the protective jacket (2) and the reactor jacket.
• a filter carrier (22) closed at the top with a replacement filter (12 ') can be inserted into the reactor (1) on the transport path.
• the used filter (12) is fastened in an externally detachable holder (28).
• the embodiments shown are preferred, very simple and easily controllable constructions, which have it modified professionally.
• another form of energy input can be selected, for example in the form of an electrical heating device, that is to say a heating wire.
• the filter is also possible to replace the filter from below in the end container area instead of from the side, which saves the lock and the transport device.
• several filters are pivotally arranged on the edge of the outlet of the reactor space, which can be swiveled in in a controlled manner and released from their holder. With such a change of the filter, however, the remaining contents of the reactor space are emptied into the final container. From there, the liquid can be pumped back into the reactor space if this should be necessary.
• the present invention offers a simple and comprehensive system for the decomposition of organic ion exchange resins, and has the following advantages in particular:
• the device is quite simple and space-saving, since it consists essentially of a reactor vessel and a protective jacket, which can be created and maintained with low construction and maintenance costs.
• the process can be extended to other types of hazardous waste, such as combustible, non-radioactive waste, and other nuclear, especially highly toxic, long-lived alpha waste, which is generated in various stages of fuel production.
• hazardous waste such as combustible, non-radioactive waste, and other nuclear, especially highly toxic, long-lived alpha waste, which is generated in various stages of fuel production.
• the process can be adapted and used for energy recovery if appropriate additional technical measures are taken.
• Radioactive substances do not evaporate due to the low operating temperature and therefore they are not spread, which, on the contrary, is a disadvantage of the previously known ashing method.
• the process can be easily controlled by controlling the amount of hydrogen peroxide.
• the device is so simple and small that it can be built on the type of waste generation, which saves extensive handling, storage and an expensive transport of the waste materials there.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Processing Of Solid Wastes (AREA)
• Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=6386764

Family Applications (1)

Country Status (6)

Families Citing this family (5)

Citations (3)

• 1989
  • 1989-08-09 DE DE19893926252 patent/DE3926252A1/de active Granted
• 1990
  • 1990-08-08 CA CA 2066741 patent/CA2066741A1/en not_active Abandoned
  • 1990-08-08 AU AU61639/90A patent/AU6163990A/en not_active Abandoned
  • 1990-08-08 WO PCT/EP1990/001299 patent/WO1991002362A1/de not_active Application Discontinuation
  • 1990-08-08 EP EP19900912270 patent/EP0486568A1/de not_active Withdrawn
  • 1990-08-09 EG EG47190A patent/EG19766A/xx active

Patent Citations (3)

Non-Patent Citations (2)

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