Emergency treatment method for radioactive pollution gas

Abstract

The invention relates to the technical field of radioactive pollution gas emergency treatment, in particular to a radioactive pollution gas emergency treatment method. The method comprises the steps of pollution gas state monitoring, primary cooling and dehumidification, secondary cooling and dehumidification, heating and dehumidification, purification and purified gas monitoring, can be quickly connected with an exhaust system of a radioactive pollution gas source in a butt joint mode, continuously purifies radioactive pollution gas, recovers or improves the treatment capacity of the radioactive pollution gas, and improves the treatment efficiency of the radioactive pollution gas. The emergency rescue capability is improved, and the radiation safety of workers, the public and the surrounding environment is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of emergency treatment of radioactive contaminated gas, and in particular to an emergency treatment method for radioactive contaminated gas. Background Art

[0002] Radioactive aerosols and radioactive gaseous wastes may be generated in uranium mining, ore dressing and hydrometallurgy, refining and conversion, uranium isotope separation, nuclear fuel element preparation, nuclear reactor operation, nuclear fuel reprocessing, radioactive waste treatment, isotope production and application, and other radioactive material operations. The main purpose of radioactive gaseous waste purification is to remove or reduce radioactive pollutants and protect workers, the public and the environment.

[0003] Commonly used methods for treating radioactive contaminated gases mainly include decay storage and fixed treatment devices. When the fixed treatment device fails or the nuclear power plant fails and the processing capacity of the fixed treatment device is exceeded, it is difficult to achieve complete storage of the radioactive contaminated gas, and emergency treatment of the radioactive contaminated gas is required. Summary of the invention

[0004] In view of the defects in the prior art, the purpose of the present invention is to provide an emergency treatment method for radioactive contaminated gas to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for emergency treatment of radioactive contaminated gas comprises the following steps:

[0007] S1: Contaminated gas status monitoring: Connect the induced draft duct of the treatment device to the discharge port of the radioactive contaminated gas source using a quick connector, turn on the centrifugal fan, monitor the temperature and humidity of the radioactive contaminated gas in the induced draft duct, and determine whether the gas temperature is less than 70°C and the humidity is less than 60%RH: if yes, execute step S5, otherwise execute step S2.

[0008] S2: Primary cooling and dehumidification: The polluted gas enters the heat pipe heat exchanger for cooling and dehumidification, so that the temperature of the polluted gas drops to 50°C; the humidity of the polluted gas after cooling is monitored: if the humidity is greater than 60%RH, execute step S3; if the humidity is less than 60%RH, execute step S5.

[0009] S3: Secondary cooling and dehumidification: After being discharged from the heat pipe heat exchanger, the polluted gas enters the evaporator for cooling and dehumidification, so that the temperature of the polluted gas drops to 40°C; the humidity of the polluted gas after further cooling is monitored: if the humidity is greater than 60%RH, execute step S4; if the humidity is less than 60%RH, execute step S5.

[0010] S4: Heating and dehumidifying: After the polluted gas is discharged from the evaporator, it enters the electric heater to heat up to 70°C and keep the humidity at 60%RH. After the polluted gas is discharged from the electric heater, execute step S5.

[0011] S5: Purification: The polluted gas enters the first filter, the second filter, the third filter and the fourth filter in sequence, and the polluted gas is filtered through four stages to become purified gas.

[0012] S6: Purified gas status monitoring: The purified gas is sucked out by a centrifugal fan and tested by an online radioactive waste gas monitoring device. If it does not meet the standard, step S5 is repeated; if it meets the standard, it is discharged into the atmosphere.

[0013] The heat pipe heat exchanger, evaporator, electric heater, centrifugal fan, first filter, second filter, third filter, fourth filter and related pipelines and valves are entirely covered with radiation shielding materials to protect personnel safety.

[0014] Furthermore, in step S5: the first filter material is made of polyester fiber felt, and the sealing gasket is made of closed-cell sponge silicone rubber; the second filter material is made of ultrafine glass fiber filter paper, and the sealing gasket is made of chloroprene rubber; the third filter is an iodine adsorption filter, the filter material is made of impregnated coconut shell activated carbon, and the sealing gasket is made of closed-cell sponge silicone rubber; the fourth filter material is made of ultrafine glass fiber filter paper; the sealing gasket is made of closed-cell sponge silicone rubber.

[0015] Furthermore, the radiation shielding material is made of lead and has a thickness of 5 to 10 mm.

[0016] Furthermore, in steps S1 and S6, the rated air volume of the centrifugal fan is 3600 m³ / h.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] It can realize integrated and mobile design, can quickly connect to the exhaust system of the radioactive contaminated gas source, continuously purify the radioactive contaminated gas, restore or improve the treatment capacity of radioactive contaminated gas, improve emergency rescue capabilities, and ensure the radiation safety of workers, the public and the surrounding environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The present invention is a flow chart of a method for emergency treatment of radioactive contaminated gas. DETAILED DESCRIPTION

[0020] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0021] like Figure 1 As shown, the present invention provides a method for emergency treatment of radioactive contaminated gas, comprising the following steps:

[0022] S1: Monitoring of contaminated gas status: Connect the induced draft duct of the treatment device to the discharge port of the radioactive contaminated gas source using a quick connector, turn on the centrifugal fan, monitor the temperature and humidity of the radioactive contaminated gas in the induced draft duct, and determine whether the gas temperature is less than 70°C and the humidity is less than 60%RH: if yes, execute step S5; otherwise, execute step S2; in order to ensure the service life of the air purification equipment and the final exhaust requirements, the temperature and humidity of the radioactive waste gas must be controlled below 70°C and 60%RH through refrigeration and dehumidification equipment.

[0023] S2: Primary cooling and dehumidification: The polluted gas enters the heat pipe heat exchanger for cooling and dehumidification, so that the temperature of the polluted gas drops to 50°C; the humidity of the polluted gas after cooling is monitored: if the humidity is greater than 60%RH, execute step S3; if the humidity is less than 60%RH, execute step S5.

[0024] S3: Secondary cooling and dehumidification: After being discharged from the heat pipe heat exchanger, the polluted gas enters the evaporator for cooling and dehumidification, so that the temperature of the polluted gas drops to 40°C; the humidity of the polluted gas after further cooling is monitored: if the humidity is greater than 60%RH, execute step S4; if the humidity is less than 60%RH, execute step S5.

[0025] S4: Heating and dehumidifying: After the polluted gas is discharged from the evaporator, it enters the electric heater to heat up to 70°C and keep the humidity at 60%RH. After the polluted gas is discharged from the electric heater, execute step S5; if the humidity of the exhaust gas is still higher than 60%RH after steps S2-S4, this method can alleviate the purification of the exhaust gas. Even if the temperature and humidity of the gas entering the air purification equipment are slightly high, it will affect the life of the filter, but it will not affect the purification efficiency in the short term. At this time, the impact of temperature and humidity on the life of the filter can be ignored, and all efforts can be made to deal with the failure of the fixed exhaust gas treatment device or the failure of the nuclear reactor.

[0026] S5: Purification: The polluted gas enters the first filter, the second filter, the third filter and the fourth filter in sequence, and the polluted gas is filtered through four stages to become purified gas.

[0027] S6: Purified gas status monitoring: The purified gas is sucked out by a centrifugal fan and tested by an online radioactive waste gas monitoring device. If it does not meet the standard, step S5 is repeated; if it meets the standard, it is discharged into the atmosphere.

[0028] The heat pipe heat exchanger, evaporator, electric heater, centrifugal fan, first filter, second filter, third filter, fourth filter and related pipelines and valves are entirely covered with radiation shielding materials to protect personnel safety.

[0029] Furthermore, in step S5: the first filter material is made of polyester fiber felt, and the sealing gasket is made of closed-cell sponge silicone rubber; the second filter material is made of ultrafine glass fiber filter paper, and the sealing gasket is made of chloroprene rubber; the third filter is an iodine adsorption filter, the filter material is made of impregnated coconut shell activated carbon, and the sealing gasket is made of closed-cell sponge silicone rubber; the fourth filter material is made of ultrafine glass fiber filter paper; the sealing gasket is made of closed-cell sponge silicone rubber.

[0030] Furthermore, the radiation shielding material is made of lead and has a thickness of 5 to 10 mm.

[0031] Specifically, according to the "Basic Standard for Ionizing Radiation Protection and Radiation Source Safety" (GB18871-2002), the dose constraint value for professional workers is 5mSv / a. Based on the calculation that the same worker works 250 hours a year, the dose rate in the cockpit is controlled to be no more than 20μSv / h. The thickness of the lead plate is initially designed to be 5 mm, which can ensure that the dose rate in the cab of the vehicle carrying the shelter is less than 0.02 mSv / h. The thicker the lead shielding layer, the lower the dose rate, but the cost and weight will also increase. After comprehensive calculation, the thickness of 5 to 10 mm is the best thickness.

[0032] Furthermore, in steps S1 and S6, the rated air volume of the centrifugal fan is 3600 m³ / h.

[0033] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for emergency treatment of radioactive contaminated gas, characterized in that: The following steps are involved: S1: Contaminated gas status monitoring: Connect the induced draft pipe of the treatment device to the discharge port of the radioactive contaminated gas source using a quick connector, turn on the centrifugal fan, monitor the temperature and humidity of the radioactive contaminated gas in the induced draft pipe, and determine whether the gas temperature is less than 70°C and the humidity is less than 60%RH: if yes, execute step S5, otherwise execute step S2; S2: Primary cooling and dehumidification: The polluted gas enters the heat pipe heat exchanger for cooling and dehumidification, so that the temperature of the polluted gas drops to 50°C; the humidity of the polluted gas after cooling is monitored: if the humidity is greater than 60%RH, step S3 is executed; if the humidity is less than 60%RH, step S5 is executed; S3: Secondary cooling and dehumidification: After being discharged from the heat pipe heat exchanger, the polluted gas enters the evaporator for cooling and dehumidification, so that the temperature of the polluted gas drops to 40°C; the humidity of the polluted gas after further cooling is monitored: if the humidity is greater than 60%RH, step S4 is executed; if the humidity is less than 60%RH, step S5 is executed; S4: Heating and dehumidifying: After the polluted gas is discharged from the evaporator, it enters the electric heater to heat up to 70°C and keep the humidity at 60%RH. After the polluted gas is discharged from the electric heater, step S5 is executed; S5: Purification: The polluted gas enters the first filter, the second filter, the third filter and the fourth filter in sequence, and the polluted gas is filtered through four stages to become purified gas; S6: Purified gas status monitoring: The purified gas is sucked out by a centrifugal fan and tested by an online radioactive waste gas monitoring device. If it does not meet the standard, step S5 is repeated; if it meets the standard, it is discharged into the atmosphere; Wherein, the heat pipe heat exchanger, evaporator, electric heater, centrifugal fan, first filter, second filter, third filter and fourth filter as well as related pipelines and valves are entirely covered with radiation shielding materials.

2. The method for emergency treatment of radioactive contaminated gas according to claim 1, characterized in that: In step S5, the first filter uses polyester fiber felt as filter material, and the sealing pad uses closed-cell sponge silicone rubber; the second filter uses ultrafine glass fiber filter paper as filter material, and the sealing pad uses chloroprene rubber; the third filter is an iodine adsorption filter, the filter material uses impregnated coconut shell activated carbon, and the sealing pad uses closed-cell sponge silicone rubber; the fourth filter uses ultrafine glass fiber filter paper as filter material, and the sealing pad uses closed-cell sponge silicone rubber.

3. The method for emergency treatment of radioactive contaminated gas according to claim 1, characterized in that: The radiation shielding material is made of lead and has a thickness of 5 to 10 mm.

4. The method for emergency treatment of radioactive contaminated gas according to claim 1, characterized in that: In the steps S1 and S6, the rated air volume of the centrifugal fan is 3600 m³ / h.

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