RU2232439C2 - Mobile installation for post accident decontamination of atmosphere in enclosed premises - Google Patents

Abstract

FIELD: environmental protection; accident elimination in enterprises using radioactive materials.

SUBSTANCE: proposed mobile installation has vehicle, control means, gas discharge and delivery conduits, units for cleaning gases from toxic materials and aerosol particles intercommunicating through pipelines for change-over to bypass, ventilation unit, pipe valves, pressure and temperature sensors. In addition installation is provided with newly introduced units for monitoring humidity, gas medium flow, concentration, and dispersion ability of radioactive alpha-, beta- and gamma-aerosols contained in gas medium, for volumetric concentration of carbon oxide, radioactive iodine, hydrochloric acid vapors, and tritium, all installed at inlet and outlet of discharge and delivery gas conduits, pressure and temperature sensors being installed in these units. Installation is also provided with tritium precipitation unit, drying unit, unit for cleaning gas flow from hydrochloric acid vapors, and unit for decontaminating gas flow from radioactive iodine. All units except for monitoring ones have gamma-ray detecting devices to check them for degree of contamination. Unit for cleaning gas flow from toxic materials and aerosol particles is built of two sub-units of which one is meant for removing carbon oxide and coarsely dispersed aerosol particles and other sub-unit, for removing finely dispersed aerosol particles. Control means is made in the form of computer-based numeric-control system and communicates with monitoring units, pipe valves, and gamma-ray detecting equipment. All units are joined into series circuit for change-over through bypass lines by means of control means so that gas flows through units in any sequence. Installation is self-propelled motor-driven carriage mounting all units.

EFFECT: enlarged functional capabilities and safety of mobile communications.

7 cl, 1 dwg

Description

The invention relates to the field of liquidation of consequences of accidents and can be used, in particular, for the prompt liquidation of consequences of accidents at nuclear power plants, at enterprises producing radioactive isotopes and nuclear materials, in research laboratories working with radioactive materials.

Known mobile device for air purification. The apparatus comprises an elongated hollow flat base, a cabinet fixed to the base with an elongated lid having an air outlet with a filter diffuser. The base has an air inlet closed by a protective grill. At the base is a hydraulic filter, which is a set of upper and lower partitions. The base of the apparatus is equipped with vehicles. The cabinet is made in the form of three sections. In the first section, a filter for fine particles and a carbon filter are fixed. The middle section at the bottom has a dust collector. The fan is fixed at the bottom of the last section. Side dust collectors are attached to the cabinet (RF patent 2042398 dated 01/09/92, IPC 6 V 01 D 47/02, 47/12, published in BI No. 24 dated 08/27/95).

The disadvantage of this apparatus is the lack of control over the air filtration process, which can lead to an insufficient degree of purification. It is also obvious that the filter set available in the apparatus cannot effectively clean the air of radioactive aerosols, including those in the vapor phase, and of radioactive gases. In addition, the vehicle available in this analogue allows you to move the device only within the premises, which significantly reduces its mobility.

Known mobile laboratory radiation monitoring, containing the main group of equipment, including a hardware complex, designed directly to determine the content of radioactive substances in samples of water, soil, air, and an auxiliary group of equipment, including instruments and devices to ensure optimal operating conditions of the main equipment , as well as creating normal working conditions for staff. The hardware complex consists of instruments for measuring the concentration of radioactive aerosols in air, gamma radiation levels, levels of radioactive contamination of surfaces, for assessing the content of strontium-90 in soil samples, artificial alpha-emitting nuclides in soil, water, vegetation and food samples, gamma spectrometric determination of the specific mass activity of cesium-137 in environmental samples, rapid analysis instruments for evaluating the increased content of cesium-137 in soil and water samples, beta activity of cesium in environmental samples and food products, a radiation counter for measuring the content of gamma-emitting radionuclides in critical organs and throughout the human body, equipment for sampling and preparing samples (certificate of the Russian Federation for utility model 0002226 dated 12/27/94, IPC 6 В 60 Р 3/32, G 01 N 23/00, published 06/16/96).

The main disadvantage of this laboratory is the lack of equipment for air purification from radioactive and toxic substances. As a result of this, it cannot be used for the prompt liquidation of the consequences of accidents.

As a prototype, a device for extinguishing a fire and cleaning the gas environment from smoke and toxic gases inside an airtight room was selected.

For transportation from the place of storage, delivery to a separate enclosed space, and removal from smoke and toxic substances, especially carbon monoxide, a mobile “air cushion” trolley was used with a gas purification unit including wet filters, a gas heater with hopcalite or another CO oxidation catalyst, an ozonizer , a fan, a foam cooler and power supply via a flexible cable, and the means for supplying the solutions used can be connected by a system of supply and drain pipelines to reserve sources nutrition. The device contains a pumping and forcing gas ducts, control means, pressure and temperature sensors. The filters and the CO oxidation catalyst are interconnected by pipelines with the possibility of switching through bypass (RF patent 2026121 from 12.28.90, IPC 6 08 08 15/00, published in BI No. 1 from 01/09/95).

The disadvantage of this design is the lack of controls for the content of harmful substances in the room where the cleaning is carried out, as well as a set of filters that are insufficient for effective air purification from radioactive substances and accompanied by accidents with a fire emission of hydrochloric acid vapor and water. In addition, the control tool in the device operates only in manual mode, which also reduces the likelihood of effective air purification due to the presence of the human factor and reduces the safety of work in connection with the presence of the operator at the scene of the accident. Therefore, this device cannot solve the problem of the alleged invention.

The technical task to be solved is the development of a mobile installation for integrated automated air purification in closed rooms after accidents (including those accompanied by a fire), in particular, with radioactive substances: tritium, radioactive iodine, and radioactive aerosols.

The technical result consists in the possibility of carrying out comprehensive air purification in an automated mode, including from radioactive substances, at the accident site with constant monitoring of the effectiveness of the degree of purification, and therefore, to increase the versatility and safety of the mobile installation.

The achievement of the technical result is ensured by a mobile installation containing a vehicle, a control device, pumping and forcing gas ducts, gas purification units from toxic substances and aerosol particles, a fan unit, pipe fittings and pressure and temperature sensors. The blocks are interconnected by pipelines with the ability to switch through bypass. The unit includes units for controlling humidity, gas flow rate, concentration and dispersion of α-, β- and γ-radioactive aerosols contained in the gas environment, and controlling the volume concentration of carbon monoxide, radioactive iodine, hydrochloric acid and tritium vapor. Control units are installed at the inlet and outlet of the pumping and forcing gas ducts, while temperature and pressure sensors are installed in these blocks. A tritium deposition unit, a drying unit, a unit for cleaning the gas stream from hydrochloric acid vapor, and a unit for cleaning the gas stream from radioactive iodine are also introduced into the installation. All blocks except the control blocks contain γ-radiation detection equipment to control the degree of contamination of the blocks. The unit for cleaning the gas stream from toxic substances and aerosol particles is made of two subunits. One of the subunits is intended for cleaning carbon monoxide and coarse aerosol particles, and the other is used for fine aerosol particles. The control tool is made in the form of an automated complex with program management. The control means is connected with control units, pipe fittings and γ-radiation detection equipment. All blocks are interconnected by pipelines in a serial circuit with switching through bypass lines using control means in such a way that the gas flow through the blocks is carried out in any sequence. In the installation, the vehicle is a self-propelled chassis driven by an engine. All installation units are installed on the chassis.

The subunit for cleaning carbon monoxide and coarse aerosol particles is made in the form of an electrostatic precipitator.

The subunit for cleaning fine aerosol particles includes a filter element made of nickel-based electrolytic powders.

The unit for cleaning the gas stream from radioactive iodine contains a sorbent substance, for example thermoxide 58.

The drying unit is divided into two subunits, and zeolite is used in each as a drying substance. The unit for cleaning the gas stream from hydrochloric acid vapor is a fabric filter, for example, with a VIOM-ANZ fabric. The unit is equipped with a ventilation shield.

Indications of control units for pressure, temperature, humidity, gas flow rate, concentration and dispersion of α-, β- and γ-radioactive aerosols contained in the gas environment, volumetric concentration of carbon monoxide, radioactive iodine, hydrochloric acid and tritium vapor installed at the inlet and the outlet of the pumping and pumping gas ducts, will allow you to set the optimal, most effective for this type of accident, gas flow cleaning modes with the help of a control tool, and will also allow you to evaluate at what stage of operation bnosti each block is cleaned during the full cleaning cycle in addition, trace contamination without protection of pipelines.

The introduction of a unit for cleaning the gas stream from hydrochloric acid vapors, a drying unit and a subunit for cleaning carbon monoxide and coarse aerosol particles into the design of the unit will provide initial purification of the gas stream from hydrochloric acid vapor, water vapor, coarse dust and carbon monoxide. The fact is that these inclusions strongly affect the process of cleaning the gas stream from radioactive substances. Vapors of hydrochloric acid and water, as well as relatively coarse dust and carbon monoxide, pollute and “poison” those units that are designed to purify radioactive iodine, finely dispersed radioactive aerosols and to precipitate tritium.

The γ-radiation detection equipment contained in the blocks will provide control of the degree of contamination of the blocks, which, firstly, will provide more complete information about the cleaning process, and, secondly, when exceeding the permissible values of contamination of a given block with γ-radioactive substances (which indicates the exhaustion of the resource block) to carry out the necessary routine maintenance.

The implementation of the control in the form of an automated complex with program control, which is connected with control units, pipe fittings and γ-radiation detection equipment, will automate the cleaning process. At the same time, firstly, the influence of the human factor on the cleaning process will be minimized, and secondly, the safety of work will increase significantly, because there will be no need for the presence of the operator at the scene of the accident.

The introduction to the installation of additional cleaning units in conjunction with the serial connection of the units to each other by pipelines with the ability to switch through bypass lines using the control means in such a way that the gas flow through the blocks is carried out in any sequence, allows you to use only those blocks in an automated mode for cleaning this type of radioactive contamination. At the same time, pipeline fittings are used in the most rational way. Thus, the problem is solved of the possibility of complex automated cleaning of the gas stream from various types of pollution in one installation.

The implementation of the vehicle in the form of a self-propelled chassis driven by an engine will provide greater mobility of the installation and increase the opportunity for maneuver. This will ensure prompt response to accidents, which is especially important in accidents with radioactive substances.

Filtering elements from VIOM-ANZ fabric, from nickel-based electrolytic powders included in the blocks, filtering elements containing sorbents Thermoxide 58 and zeolite increase the efficiency of cleaning the gas stream from hydrochloric acid vapor, a finely dispersed fraction of radioactive aerosols, radioactive iodine and water vapor.

The ventilation panel will allow cleaning the gas stream in a so-called closed cycle until the content of harmful substances in the gas is reduced to an acceptable level.

In the inventive installation, the principle of cascading cleaning is implemented, the cleaning sequence from each previous one allows not to “poison” the subsequent filter. This is accomplished by introducing units for cleaning the gas stream from hydrochloric acid vapor, a drying unit, and a subunit for cleaning carbon monoxide and coarse aerosol particles. Carrying out such cleaning eliminates the “poisoning” of the blocks for the purification of radioactive iodine, etc. All these operations are carried out with continuous monitoring during the cleaning process. This new approach enables effective complex cleaning of the above components. The installation is based on the principle of self-control, i.e. the ability to evaluate the health of cleaning units, implemented using control units and γ-ray detection equipment.

Figure 1 presents the installation diagram, where:

- 1-33 - switching cranes .;

- 34 - block input control;

- 35 - block output control;

- 36 - block deposition of tritium;

- 37 - drying unit;

- 38 - unit for cleaning the gas stream from hydrochloric acid vapor;

- 39 - unit for cleaning the gas stream from radioactive iodine;

- 40 - subunit for cleaning carbon monoxide and coarse aerosol particles;

- 41 - filter for cleaning from fine aerosol particles;

- 42 - ventilation shield;

- 43 - fan unit.

Consider an example of a specific installation, which implements the inventive installation for air purification in rooms after accidents with radioactive substances:

- the unit for cleaning the gas stream from radioactive iodine 39 contains a sorbing substance thermoxide 58, which is a synthetic material based on difficultly soluble inorganic compounds in the form of strong spherical granules;

- a subunit for cleaning carbon monoxide and coarse aerosol particles 40 is made in the form of an electrostatic precipitator;

- a subunit for cleaning fine aerosol particles 41 includes filter elements from nickel-based electrolytic powders;

- in the drying unit 37, consisting of two parts, zeolite is poured;

- unit for cleaning the gas stream from hydrochloric acid vapor 38 is a fabric filter. The filter used VIOM-ANZ fabric;

- between the ventilation panel 42 and the cleaning units are pipelines in the form of hoses that do not have protection against γ radiation and can cause radiation exposure to personnel. The assessment by the control units of the level of radiation pollution makes it possible to decide on the use of personal protective equipment.

The components of the installation are placed on the chassis of the Ural vehicle, which has a trailer with a rigid coupling (not shown).

The device operates as follows.

In an accident, a car drives up to the room in which the accident occurred, for example, with radioactive substances. Using a ventilation shield 42, the inlet and outlet gas ducts (for example, in a window opening) are secured with exits to the room. At the same time, the installation itself is located outside the premises at a safe distance.

Depending on the type of accident, the algorithm of the device is set.

For example, in an accident involving the release of uranium 235 or plutonium 239, the gas stream cleaning process is divided into two cycles (for almost any type of radioactive substance accident, the cleaning process is divided into two cycles).

The first cycle includes the passage of the gas stream through the unit for cleaning the gas stream from hydrochloric acid vapor 38 (drawing), one of the parts of the drying unit 37 and the bypass line, the subunit for cleaning carbon monoxide and coarse aerosol particles 40, fan unit 43. Cranes 1, 2 , 3, 23, 25, 4, 5, 26, 31 at the same time open. Gas passing through the fabric of VIOM - ANZ, zeolite and electrostatic precipitator is cleaned of hydrochloric acid and water vapor, carbon monoxide and coarse aerosols.

The direction of flow through the bypass line and only through one of the parts of the drying unit 37 is due to the economic mode of drainage. For effective cleaning of the gas flow in the installation blocks, it is enough to reduce the air humidity to 70%. Given the high ability of zeolites to absorb moisture, it is enough to drain part (about half) of the gas stream, for example, to a moisture content not exceeding 30-40% (these moisture values are provided by the drying unit 37). Then, the dried portion of the gas stream is mixed with the wet portion of the gas stream. The total humidity will not exceed 70% necessary for effective cleaning. Thus, zeolite is used to select the minimum required amount of moisture. The resource of the drying unit in this case increases.

The gas stream that has undergone such an initial treatment is discharged through the ventilation panel 42 into the room again. Quantitative indicators of the content of impurities in the gas stream are constantly supplied from the input 34 and output control units 35, as well as the γ-radiation detection equipment located in the cleaning and drying units, to the control complex. The first purification cycle will be completed only when the content of hydrochloric acid vapor, water vapor, coarse aerosols and carbon monoxide in the gas stream does not decrease to an acceptable level.

After that, the control complex closes the taps 4, 23 and 25 and opens the taps 29, 6, 7, 11, 9, 15, 22 21, 13, 8. There is a switch to bypass lines to ensure the purification of the gas stream in the second cycle.

The gas stream in the second cycle will pass not only through the units for cleaning the gas stream from hydrochloric acid vapor 38, the second part of the drying unit 37, the bypass line and the subunit for cleaning carbon monoxide and coarse aerosol particles 40, but also through the subunit for cleaning fine aerosol particles 41, in which the gas stream is cleaned of radioactive aerosols with a particle size of up to 0.15 microns. The first cleaning cycle protects the subunit for cleaning from fine aerosol particles 41 from the effects of hydrochloric acid, water, carbon monoxide and coarse dust vapors that can quickly disable the subunit.

Similar to the process of cleaning the gas medium in the accident with uranium 235 or plutonium 239, the cleaning process occurs in the accident with an isotopic source, for example, cobalt 60 (including in an accident with fire), and in an accident with the release of tritium. By switching to bypass lines, the gas flow will be directed to remove radioactive substances along the shortest path to those units of the installation that are designed for their deposition.

A special role in the installation is played by a control tool made in the form of an automated complex with program control. The complex reads indicators from control units and γ-radiation detection equipment for cleaning and drying units, and then analyzes them using software tools. After the combination of indications from the control units and the detection equipment becomes consistent with those laid down in the program, the complex will issue the necessary commands for changing operating modes (switching to the corresponding cleaning lines).

It should be emphasized that the above operation of the installation is just one of the options for the possibility of its use. The presence of the elements that make up the installation allows it to be used both as a mobile laboratory for environmental monitoring, and as air purification during fires, during accidents at chemical plants, etc.

At present, theoretical calculations have been completed to determine the flow regimes of the gas stream from the gas ducts of the installation and to describe the processes of filtering the gas stream. It is assumed that the gas flow rate in the installation will be at least 1000 m ³ / h, and the diameter of the gas ducts - 160 mm. Mock-up samples of the components of the installation were made, and their tests were carried out. The data obtained provide a basis for confirming the technical result.

Claims (7)

1. A mobile installation for air purification in enclosed spaces after accidents, containing a vehicle, a control device, pumping and pumping gas ducts, gas purification units from toxic substances and aerosol particles, interconnected by pipelines with the possibility of switching through bypass, fan unit, pipe fittings , pressure and temperature sensors, characterized in that the unit contains control units for humidity, gas flow rate, concentration and dispersion contained in the gas medium de α-, β-, γ-radioactive aerosols, control the volume concentration of carbon monoxide, radioactive iodine, hydrochloric acid vapor, tritium and are installed at the inlet and outlet of the pumping and forcing gas ducts, while temperature and pressure sensors are installed in these blocks, as well as a tritium deposition unit, a drying unit, a unit for cleaning the gas stream from hydrochloric acid vapor, a unit for cleaning the gas stream from radioactive iodine were introduced; all units except the control units contain γ-radiation detection equipment to control the degree of contamination units, the unit for cleaning the gas stream from toxic substances and aerosol particles is made of two subunits, one of the subunits is designed to clean carbon monoxide and coarse aerosol particles, and the other from fine aerosol particles, the control tool is made in the form of an automated complex with software control and is connected with control units, pipe fittings and γ-radiation detection equipment, while all blocks are interconnected by pipelines in series a circuit with the ability to switch through bypass lines using control means so that the gas flow through the blocks is in any sequence, the vehicle is a self-propelled chassis driven by an engine, and all blocks are installed on it. 2. Installation according to claim 1, characterized in that the subunit for cleaning carbon monoxide and coarse aerosol particles is made in the form of an electrostatic precipitator. 3. Installation according to claim 1 or 2, characterized in that the subunit for cleaning fine aerosol particles includes a filter element made of nickel-based electrolytic powders. 4. Installation according to any one of claims 1 to 3, characterized in that the unit for cleaning the gas stream from radioactive iodine contains a sorbent substance, for example, thermoxide 58. 5. Installation according to any one of claims 1 to 4, characterized in that the drying unit is divided into two subunits, and in each zeolite is used as a drying substance. 6. Installation according to any one of claims 1 to 5, characterized in that the unit for cleaning the gas stream from hydrochloric acid vapor is a fabric filter, for example, with a VIOM-ANZ fabric. 7. Installation according to any one of claims 1 to 6, characterized in that it is equipped with a ventilation shield.