CN105499217B - Clean dirt method and device in a kind of fusion reactor hot cell - Google Patents

Abstract

The invention relates to a method and device for cleaning and decontaminating a thermal chamber of a fusion reactor. The method of combining triple airlock chamber isolation and cladding structure is adopted to isolate the cleaning unit from the hot outdoor environment, so as to facilitate the cleaning of radioactive dust and carbon dioxide waste gas. Effective collection and post-processing, the technological process is simple and easy, avoiding the harm to the environment caused by the radioactive effluent of nuclear facilities caused by the diffusion of radioactive particles in the hot chamber in the existing scheme, and can also greatly reduce the risk of occupational exposure of employees, and at the same time avoid In the cleaning process, the large amount of solid carbon dioxide sublimation of the cleaning agent has an impact on the detritium removal system in the hot chamber, and it can also prevent other components and impurities from entering the cleaning waste, realize the simplification of cleaning waste, and facilitate the post-processing of radioactive waste.

Description

A method and device for cleaning and decontaminating a thermal chamber of a fusion reactor

technical field

The invention relates to a cleaning and decontamination process method and device in a thermal chamber of a fusion reactor, belonging to the field of radioactive pollution control and treatment.

Background technique

The hot cell is a place for dealing with radioactive waste. Efficient and reliable cleaning technology can effectively reduce the dose of occupational exposure and control related radioactive effluents from entering the natural environment, and play a role in preventing the spread of radioactive contacts and pollutants.

The relevant nuclear and tritium-related process procedures in the thermal chamber are quite complicated processes. The cleaning process is a very necessary and indispensable step in the maintenance process of the fusion device's internal components, which directly affects the life of the relevant remote-operated equipment inside the hot chamber and the degree of radioactive contamination, as well as the occupational exposure dose of relevant employees and the radioactivity of nuclear facilities. The pollution of the effluent to the environment.

Relevant studies have shown that volatile particle shot peening is the preferred cleaning method in the thermal chamber of fusion devices, but it also has considerable problems: a large amount of carbon dioxide gas will bring many potential risks and problems to the huge gas processing system in the thermal chamber. Therefore, the method of dry ice blasting cleaning has been pending, which has hindered the progress of research and development of related technologies for hot cells.

Contents of the invention

The technical problem solved by the invention: in view of the fact that the detritium removal system of the hot chamber of the existing fusion device cannot handle the blast cleaning agent carbon dioxide gas on a large scale, which causes the detritium removal system to fail, and also greatly increases the limitation of the choice of cleaning methods in the hot chamber, it provides a The method and device for cleaning and decontaminating the hot chamber of a fusion device can realize the cleaning and decontamination task of the radioactively contaminated surface in the hot chamber by the carbon dioxide blasting cleaning scheme, and can also avoid the diffusion of radioactive dust in the hot chamber, and solve the problem of the current hot chamber Tritium removal systems cannot handle the CO2 problem.

The present invention is realized through the following technical solutions: a method for cleaning and decontaminating the thermal chamber of a fusion reactor, and the realization steps are as follows:

(1) Vacuumize and inflate the first-level airlock chamber: After the parts to be cleaned enter the first-level airlock chamber, the mixed gas brought in from the hot chamber in the first-level airlock chamber is pumped into a vacuum state to achieve the internal and external environment and gas atmosphere The purpose of isolation is to fill the interior of the first-level airlock chamber after vacuuming with low-temperature carbon dioxide gas, and the low-temperature carbon dioxide gas fills the relevant cavity to complete the gas exchange process, and transfer the parts to be cleaned out of the first-level airlock chamber and enter the cleaning room;

(2) Explosive cleaning, purging and carrier gas in the cleaning room: In the cleaning room, high-pressure and low-temperature carbon dioxide gas is used as a power source to drive dry ice particles to be cleaned by shot blasting, and then high-pressure carbon dioxide gas is used to purge the surface of the parts, and then loaded The flow of gas is opened to take the dusty gas out of the cleaning room for corresponding harmless post-treatment, and then the cleaned parts enter the secondary airlock chamber;

(3) Vacuumize and return air in the secondary airlock chamber: in the secondary airlock chamber, vacuumize to achieve the purpose of isolating dust and gas inside the cleaning chamber; flush clean carbon dioxide into the vacuumed secondary airlock chamber Gas, to achieve the purpose of transitional impurity environment, and then enter the air shower

(4) Air shower: In the air shower room, high-speed carbon dioxide gas flow is sprayed through the air shower nozzle to blow off the adsorbed and residual radioactive dust on the surface of the components to achieve the purpose of local purification; after the air shower is completed, the corresponding components enter the third-level airlock chamber;

(5) Vacuumize and return air in the three-stage airlock chamber: In the three-stage airlock chamber, vacuumize all carbon dioxide gas to prevent it from entering the external hot cell gas environment, and then rush into the internal gas of the hot cell environment to complete gas isolation and exchange.

The temperature of the low-temperature carbon dioxide gas in the step (1) is below -40 degrees Celsius and kept for 15-20 minutes to reduce the impact of waste heat and decay heat on the cleaning product, and prevent a large amount of difficult-to-handle cleaning by-product tritium from being produced during the cleaning process water.

The adjustable range of pressure in the high-pressure carbon dioxide gas in the step (2) is 10-500 bar.

A cleaning and decontamination device in a thermal chamber of a fusion reactor, characterized in that it includes a first-level airlock chamber, a second-level airlock chamber, a third-level airlock chamber, a cleaning room, an air shower room, an inner layer cladding structure, an outer cladding Covering structure, transportation track, double-layer airtight door, maintenance emergency window; the left side of the first-level airlock chamber is connected with the hot room, and the right side is connected with the cleaning room; the right side of the cleaning room is connected with the second-level airlock The right side of the lock chamber is connected with the air shower; the right side of the air shower is connected with the third-level airlock chamber, and the right side of the third-level airlock chamber is connected with the hot chamber. The airlock chambers at all levels are isolated from the left and right connection areas by double-layer airtight doors, and there are normally closed maintenance emergency windows reserved on the top of the airlock chambers of the first and third stages; , the components in the reactor enter the hot chamber from the dock, and the larger components are disassembled and divided into several sub-components that need to be cleaned. After the components to be cleaned enter the first-level airlock chamber, the mixed gas in the first-level airlock chamber is pumped into a vacuum state, and then rush into the low-temperature carbon dioxide gas to fill the relevant cavity. The temperature of carbon dioxide is controlled below -40 degrees Celsius, and the gas exchange process is completed after keeping for 15-20 minutes. The entire cleaning process is carried out in a single carbon dioxide gas atmosphere. Transferred out of the airlock chamber, transported by rails and transport vehicles to the cleaning room, using carbon dioxide blasting to clean the contaminated surface, after the blasting cleaning is completed, the weak solid pollutants contaminated on the surface are separated from the substrate, and then the surface is purged and cleaned with high-pressure carbon dioxide gas, and then The carrier gas is opened to take the dust-laden gas out of the cleaning chamber. The main cleaning steps are completed so far, and then enters the secondary airlock chamber. After the airlock chamber is sealed, the airlock chamber is vacuumed to isolate the residual dust-containing gas in the cleaning chamber. After inflating, open the gate and enter the air shower room. After the high-flow air shower, enter the third-level airlock room, extract carbon dioxide gas to prevent it from entering the hot room environment, rush into the hot room ambient gas, and then exit the third-level air lock room. After preliminary packaging, After entering the warehouse to complete all the cleaning process, enter the next maintenance link.

Compared with prior art, the beneficial effect of the present invention is:

(1) The cleaning effect is good. The invention adopts cladding and multi-stage air lock chambers to isolate the cleaning indoor environment from the hot outdoor environment, so that material exchange does not occur inside and outside the cleaning room, which is beneficial to the collection of radioactive particles and the regeneration cycle of cleaning waste, and the removal of radioactive particles is more efficient. Sufficiently, the collection effect of radioactive particles is better, the gas leaking into the hot chamber is difficult to be removed by the detritium system, and the carbon dioxide gas is less, and only a very small amount of cleaning agent leaks into the hot chamber.

(2) The technological process of the present invention is simple and easy to operate, and is especially suitable for large-scale maintenance and cleaning of components in the thermal chamber.

Description of drawings

Fig. 1 is the process flow diagram of the inventive method;

Fig. 2 is a relative positional relationship and a structural cross-sectional view in the heat chamber where the device of the present invention is located;

Fig. 3 is an internal sectional view of the device of the present invention.

detailed description

In order to express the purpose, technical solutions and advantages of the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

As shown in Figure 1: the process flow of cleaning and decontamination in the hot chamber involved in the present invention:

Vacuuming: The main purpose of vacuuming is to isolate the environment and gas atmosphere in different areas. This step prevents gas exchange between the mixed gas in the hot chamber and the gas environment in the cleaning unit, and achieves the purpose of isolating the indoor and outdoor environments and gas atmosphere. .

Inflating: Fill the first-stage airlock after vacuuming with low-temperature carbon dioxide gas to complete the gas exchange process.

Blast cleaning: After the environmental isolation and gas exchange are completed, dry ice particles are pushed through the injector under the pressure of high-pressure and low-temperature carbon dioxide gas, and sprayed on the surface to be cleaned, so as to adhere to the surface to be cleaned and loosen radioactive dust and radiation damage of activated materials Loose materials are separated to achieve the purpose of cleaning and decontamination.

Purge: purge the surface to be cleaned and the corresponding position in the cladding with high-pressure gas to blow off loose granular dust.

Carrier gas: increase the flow rate and flow rate of the gas in the cladding, take the cleaned exhaust gas and particles out of the cladding structure, and bring them into the purification and filtration device from the corresponding channel.

Vacuuming: After the cleaning is completed, the corresponding parts enter the secondary airlock chamber, and vacuumize to achieve the purpose of isolating dust and gas inside the cleaning chamber.

Inflating: Pour clean carbon dioxide gas into the vacuumed secondary airlock chamber to achieve the purpose of transitioning the impurity environment.

Air shower: Enter the air shower room, spray clean carbon dioxide airflow through the air shower nozzle to blow off the adsorbed and residual radioactive dust on the surface of the components to achieve the purpose of local purification.

Vacuuming: After the air shower is over, enter the third-level airlock chamber, and vacuumize all carbon dioxide gas to prevent it from entering the external hot cell gas environment.

Air return: The airlock chamber rushes into the air inside the hot chamber environment to complete the gas isolation and exchange.

Packaging: Preliminary packaging after leaving the third-level airlock.

Storage: enter the cache storage, pending further processing.

As shown in Figures 2 and 3, when the fusion device needs to be maintained, the remote operation and maintenance devices for different internal components remove the internal components from the main engine maintenance window out of the vacuum chamber and then enter the thermal chamber for related maintenance. In the embodiment of the present invention, the cladding module is taken as an example. After the reactor is shut down and the main engine turns on the vacuum, the remote operation device enters the stack through the remote operation maintenance window 1 of the main engine of the device, and the components in the stack are separated from the main engine. The components in the stack to be maintained Packaged and transported by the transfer Cask trolley 2, after the transfer Cask trolley 2 is docked with the dock port of the hot cell docking station 3, the internal components of the stack enter the buffer storage area of the thermal chamber docking station 3, and the larger parts are then disassembled and divided into several parts as needed For small parts to be cleaned, open a sealed door of the double-layer door structure docked with the first-level airlock chamber 4 and the docking station, and close the connection between the docking station 3 and the first-level airlock chamber 4 after the parts to be cleaned enter the first-level airlock chamber 4 The airtight door between the stacks exhausts the gas contained in the cavities of the internal components to form a vacuum state, and then rushes into the low-temperature carbon dioxide gas to fill the relevant cavities. The temperature of the carbon dioxide is controlled below -40 degrees Celsius and kept for 15 minutes (to reduce waste heat and The effect of decay heat on the cleaning products, preventing the cleaning process from producing difficult-to-handle cleaning by-product tritium water), and then completing the gas exchange process, the entire cleaning process is carried out in a carbon dioxide atmosphere, and then the primary airlock chamber is opened to connect with the cleaning room The parts to be cleaned are transferred out of the first-level airlock chamber 4 and enter the cleaning chamber 5. High-pressure and low-temperature carbon dioxide gas is used as a power source to push dry ice particles to perform shot blasting cleaning on the parts to be cleaned, and then use high-pressure carbon dioxide gas to purge and clean them. surface, and then the carrier gas is opened to take the dusty gas out of the cleaning chamber. After the main cleaning step is completed, it enters the secondary airlock chamber 6. After the secondary airlock chamber is sealed, the airlock chamber is evacuated to isolate the dust in the cleaning chamber. Residual dust-containing gas, after inflating, opens the gate and enters the air shower room 7. After the high-flow air shower, it enters the third-level airlock room 8, extracts carbon dioxide gas to prevent it from entering other areas of the hot chamber 9, and rushes into the low-temperature nitrogen gas to exit the third-level air lock room. Lock chamber 8, after preliminary packaging, is put into storage to complete all cleaning processes.

The cross-sectional view of the device in the present invention is shown in Figure 3, wherein the primary airlock chamber 4 connected to the hot cell docking station mainly contains the first double-layer airtight door 10 and the second double-layer airtight door 12, the transportation track 11 and the maintenance emergency Window 13, the primary airlock chamber 4 and the cleaning chamber 5 are connected through the second double-layer airtight door 12, the cleaning chamber 5 is composed of an outer cladding structure 14 and an inner cladding structure 15, and the left and right secondary airlock chambers 6 are respectively The cleaning room 5 and the air shower room 7 are connected by the third double-layer airtight door 16 and the fourth double-layer airtight door 17, and the air shower room 7 right side is connected with the third-level airlock chamber 8 by the double-layer airtight door 18, and the third-level air lock chamber The right side of the lock chamber 8 is connected with other areas of the heat chamber, and mainly includes a fifth double-layer airtight door 18 and a sixth double-layer airtight door 21 , a transport track 19 and a maintenance emergency window 20 .

The air lock chambers in the present invention adopt a double-layer sealed door structure as shown in Figure 3. When in use, only one side is opened and the other side is closed. After completing the relevant vacuuming and inflation, the other side is opened to isolate and connect two The role of material exchange in space.

In a word, the present invention provides a process flow for the material barrier and isolation of cleaning and decontamination units in the thermal chamber of a fusion device, which can realize the cleaning and decontamination waste group of the fusion device and the fusion reactor thermal chamber in the special environment involving nuclear and tritium. The points are single and do not exchange substances with the hot cell environment. The process method adopts the combination of triple airlock isolation and cladding structure to isolate the cleaning unit from the hot outdoor environment, which is convenient for effective collection and post-processing of the radioactive dust and carbon dioxide waste gas cleaned out. The process flow is simple and easy. It avoids the environmental hazards caused by the radioactive effluent of nuclear facilities caused by the diffusion of radioactive particles in the hot chamber caused by the existing scheme, and can also greatly reduce the risk of occupational exposure of employees. The impact caused by the tritium removal system can also prevent other components and impurities from entering the cleaning waste, realize the simplification of cleaning nonsense, and facilitate the post-processing of radioactive waste.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (4)

1. A method for cleaning and decontaminating the thermal chamber of a fusion reactor, characterized in that the realization steps are as follows: (1) Vacuumize and inflate the first-level airlock chamber: After the parts to be cleaned enter the first-level airlock chamber, the mixed gas brought in from the hot chamber in the first-level airlock chamber is pumped into a vacuum state to achieve the internal and external environment and gas atmosphere. The purpose of isolation is to fill the interior of the first-level airlock chamber after vacuuming with low-temperature carbon dioxide gas, and the low-temperature carbon dioxide gas fills the relevant cavity to complete the gas exchange process, and transfer the parts to be cleaned out of the first-level airlock chamber and enter the cleaning room; The temperature of cryogenic carbon dioxide gas is below -40 degrees Celsius; (2) Blast cleaning, purging and carrier gas in the cleaning room: In the cleaning room, high-pressure and low-temperature carbon dioxide gas is used as a power source to drive dry ice particles to be cleaned by shot blasting, and then high-pressure carbon dioxide gas is used to purge the surface of the parts, and then loaded The flow of gas is opened to take the dusty gas out of the cleaning room for corresponding harmless post-treatment, and then the cleaned parts enter the secondary airlock chamber; (3) Vacuumize and return air in the secondary airlock chamber: in the secondary airlock chamber, vacuumize to achieve the purpose of isolating dust and gas inside the cleaning chamber; fill the vacuumed secondary airlock chamber with clean carbon dioxide Gas, to achieve the purpose of transitional impurity environment, and then enter the air shower; (4) Air shower: In the air shower room, the high-speed carbon dioxide gas flow is sprayed through the air shower nozzle to blow off the adsorbed and residual radioactive dust on the surface of the components to achieve the purpose of local purification; after the air shower is completed, the corresponding components enter the third-level airlock chamber; (5) Vacuumize and return air in the third-stage airlock chamber: In the third-stage airlock chamber, all carbon dioxide gas is evacuated to prevent it from entering the external hot cell gas environment, and then filled with the internal gas of the hot cell environment to complete gas isolation and exchange. 2. The method for cleaning and decontaminating the thermal chamber of a fusion reactor according to claim 1, characterized in that: the low-temperature carbon dioxide gas in the step (1) fills the relevant cavity and keeps it for 15-20 minutes to reduce waste heat and decay heat The impact on the cleaning product, preventing the large amount of difficult-to-handle by-product tritium water from being produced during the cleaning process. 3 . The method for cleaning and decontaminating the thermal chamber of a fusion reactor according to claim 1 , wherein the adjustable range of the pressure of the high-pressure carbon dioxide gas in the step (2) is 10-500 bar. 4 . 4. A cleaning and decontamination device in a thermal chamber of a fusion reactor, characterized in that: it includes a primary airlock chamber, a secondary airlock chamber, a tertiary airlock chamber, a cleaning chamber, an air shower, an inner cladding structure, an outer Layer cladding structure, transportation track, double-layer airtight door, maintenance emergency window; the left side of the primary airlock chamber is connected with the heat chamber, and the right side is connected with the cleaning chamber; the right side of the cleaning chamber is connected with the secondary airlock chamber, and the second The right side of the first-level airlock is connected to the air shower; the right side of the air shower is connected to the third-level airlock, and the right side of the third-level airlock is connected to the hot room. The airtight door is isolated, and there are normally closed maintenance emergency windows reserved on the top of the first and third-stage airlock chambers; after the remote operation device removes the internal components from the main engine out of the vacuum chamber, the internal components enter the hot chamber from the dock port, which is relatively large. After the parts are disassembled, they are divided into several sub-components that need to be cleaned. After the parts to be cleaned enter the first-level airlock chamber, the mixed gas in the first-level airlock chamber is pumped into a vacuum state, and then the relevant air is filled with low-temperature carbon dioxide gas. chamber, the temperature of carbon dioxide is controlled below -40 degrees Celsius, and the gas exchange process is completed after keeping for 15-20 minutes. The entire cleaning process is carried out in a single carbon dioxide gas atmosphere. Clean the contaminated surface with carbon dioxide blasting. After blasting and cleaning, the weak solid pollutants contaminated on the surface are separated from the substrate, and then the surface is cleaned with high-pressure carbon dioxide gas. After that, the carrier gas is turned on to take the dusty gas out for cleaning. The main cleaning steps have been completed so far, and then enter the secondary airlock chamber. After the airlock chamber is sealed, the airlock chamber is evacuated to isolate the residual dusty gas in the cleaning chamber. After inflating, the gate is opened and enters the air shower chamber. After showering, enter the third-level airlock chamber, remove carbon dioxide gas to prevent it from entering the hot chamber environment, and then exit the third-level airlock chamber after filling the hot chamber ambient gas. After preliminary packaging, it is put into the warehouse to complete all cleaning processes, and then enters the next maintenance links.