CN110415854B - A method for reducing the amount of decomposing and volatilizing radioactive waste based on inert gas - Google Patents

Abstract

The invention provides a method for reducing the decomposition and volatilization amount of radioactive waste based on inert gas, which is used in a pyrolysis furnace, comprising: after the radioactive waste is mixed in a mixer, inert gas is introduced into the mixer; After a certain period of time after the start of mixing, the pyrolysis chamber is evacuated, and inert gas is injected into the pyrolysis chamber; the oxygen content of the air in the pyrolysis chamber is analyzed by an oxygen analyzer. When the oxygen content in the pyrolysis chamber is lower than At the preset value, transfer the radioactive waste in the mixer to the pyrolysis chamber; start pyrolysis. The method for reducing the decomposition and volatilization of radioactive waste based on an inert gas is used in a pyrolysis furnace to provide protection for the radioactive waste that needs to be pyrolyzed, and to isolate it from oxygen, thereby reducing the volatilization of the radioactive waste.

Description

A method for reducing the amount of decomposing and volatilizing radioactive waste based on inert gas

technical field

The invention relates to the technical field of nuclear waste treatment, in particular to a method for reducing the decomposition and volatilization of radioactive waste based on an inert gas.

Background technique

At present, the global energy is very scarce. In response to energy conservation, environmental protection and emission reduction, countries around the world are vigorously accelerating the development of nuclear power. China will also vigorously develop clean power sources. Nuclear power is the main direction of the country's future power supply structure adjustment, and the investment scale will be greatly exceeded. conventional power plants. The country's strategy for nuclear power development has changed from "moderate development" to "active development". In this context, China's nuclear power energy will have a good opportunity for development.

Currently, radioactive waste from nuclear facilities such as nuclear power plants or research centers is processed to reduce its volume and at the same time convert it into stable waste suitable for temporary storage or disposal. Thermal treatment is often the most effective way to reduce the volume of organic waste. For low-level radioactive waste, the recommended disposal method is incineration. For moderately radioactive waste, thermal decomposition in an inert gas, ie pyrolysis, is the preferred treatment method.

The pyrolysis furnace includes: a mixer, a pyrolysis chamber, a waste gas temporary storage chamber and a pebble bed chamber; the radioactive waste is first mixed in the mixer, and then enters the pyrolysis chamber for pyrolysis; the waste gas generated by pyrolysis passes through the waste gas temporary storage chamber Enter the pebble bed room, and finally discharge into the atmosphere after passing through the waste gas treatment device. In the above pyrolysis process, how to reduce the pyrolysis volatilization of radioactive waste so that it can remain at the bottom of the pyrolysis furnace as much as possible.

SUMMARY OF THE INVENTION

The invention provides a method for reducing the decomposition and volatilization of radioactive waste based on inert gas, which is used in a pyrolysis furnace to provide protection for the radioactive waste that needs to be pyrolyzed, and isolate it from oxygen, thereby reducing the volatilization of the radioactive waste.

A method for reducing the decomposition and volatilization of radioactive waste based on an inert gas provided by an embodiment of the present invention includes:

After the radioactive waste is mixed in the mixer, inert gas is introduced into the mixer;

The pyrolysis chamber is evacuated after a certain time after the mixing of the radioactive waste in the mixer begins,

Pour inert gas into the pyrolysis chamber;

The oxygen content of the air in the pyrolysis chamber is analyzed by an oxygen analyzer,

When the oxygen content in the pyrolysis chamber is lower than the preset value, transferring the radioactive waste in the mixer into the pyrolysis chamber;

Pyrolysis begins.

In one embodiment, after starting the pyrolysis, it further comprises:

Every preset time; close the channel between the waste gas temporary storage chamber and the pyrolysis chamber,

Open the outlet of the exhaust gas temporary storage chamber located in the pebble bed chamber.

In one embodiment, before starting the pyrolysis, it further comprises:

Inert gas was introduced into the pebble bed chamber.

In one embodiment, after a certain period of time after the radioactive waste is mixed in the mixer, the pyrolysis chamber is evacuated, and an inert gas is injected into the pyrolysis chamber;

After performing the above steps, repeat the above steps for a total of 3 times.

In one embodiment, including:

After the pyrolysis is over, open the outlet of the waste gas temporary storage chamber and the channel between the waste gas temporary storage chamber and the pyrolysis chamber; and continue to introduce inert gas into the pyrolysis chamber for a period of time;

In one embodiment, after the radioactive waste is put into the mixer, before starting to mix, the mixer is evacuated; after the vacuum is evacuated, the mixing is started.

In one embodiment, the gas evacuated when the mixer is evacuated is directly introduced into the pebble bed chamber, and then discharged from below the pebble bed chamber after passing through the pebble bed, and enters the waste gas treatment device.

In one embodiment, the gas evacuated by vacuuming when the pyrolysis chamber is evacuated is directly introduced into the pebble bed chamber, and then discharged from below the pebble bed chamber after passing through the pebble bed, and enters the waste gas treatment device.

In one embodiment, the inert gas includes: nitrogen.

Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description, claims, and drawings.

The technical solutions of the present invention will be further described in detail below through the accompanying drawings and embodiments.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and are used to explain the present invention together with the embodiments of the present invention, and do not constitute a limitation to the present invention. In the attached image:

FIG. 1 is a schematic diagram of a method for reducing the decomposing and volatilizing amount of radioactive waste based on an inert gas with the lowest specific energy in an embodiment of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

An embodiment of the present invention provides a method for reducing the decomposing and volatile amount of radioactive waste based on an inert gas, as shown in FIG. 1 , including:

After the S1 radioactive waste is mixed in the mixer, inert gas is introduced into the mixer;

S2 vacuumizes the pyrolysis chamber after a certain period of time after the radioactive waste is mixed in the mixer,

S3 flushes the inert gas into the pyrolysis chamber;

S4 analyzes the oxygen content of the air in the pyrolysis chamber through an oxygen analyzer,

S5, when the oxygen content in the pyrolysis chamber is lower than the preset value, transfer the radioactive waste in the mixer into the pyrolysis chamber;

S6 starts pyrolysis.

By rushing inert gas into the mixer and pyrolysis chamber in the pyrolysis furnace, the radioactive waste is protected by inert gas during the whole process of treatment, so that it is isolated from oxygen, thereby reducing the volatilization of radioactive waste; After the radioactive waste is pyrolyzed, there will be more residues in the pyrolysis chamber than normal pyrolysis, and the waste that needs to be absorbed in the back-end exhaust gas treatment device will be less, thereby extending the service life of the exhaust gas treatment device.

In one embodiment, after starting the pyrolysis, it further comprises:

Every preset time; close the channel between the waste gas temporary storage chamber and the pyrolysis chamber,

Open the outlet of the exhaust gas temporary storage chamber located in the pebble bed chamber.

By closing the channel between the waste gas temporary storage chamber and the pyrolysis chamber, and then opening the outlet of the waste gas temporary storage chamber at the bottom of the pebble bed, the waste gas volatilized after the pyrolysis of radioactive waste is discharged. It also prevents outside air from escaping into the pyrolysis chamber when the exhaust gas is opened.

In order to exhaust the air in the pebble bed room, in one embodiment, before starting the pyrolysis, it further includes:

Inert gas was introduced into the pebble bed chamber.

In order to ensure that the oxygen in the pyrolysis chamber is completely drained; in one embodiment, after a certain period of time after the radioactive waste is mixed in the mixer, the pyrolysis chamber is evacuated and flushed into the pyrolysis chamber inert gas;

After the above steps are performed, the above steps are repeatedly performed for a total of 3 times.

In order to ensure that all the exhaust gas from pyrolysis is discharged from the pyrolysis chamber; in one embodiment, it includes:

After the pyrolysis is over, open the outlet of the waste gas temporary storage chamber and the channel between the waste gas temporary storage chamber and the pyrolysis chamber; and continue to introduce an inert gas into the pyrolysis chamber for a period of time

In order to improve the efficiency of exhausting air; in one embodiment, after the radioactive waste is put into the mixer and before starting to mix, the mixer is evacuated; after the vacuum is evacuated, the mixing is started. Improve the efficiency of exhaust air by vacuuming first; it is more efficient than directly feeding inert gas.

In order to realize the treatment of the gas extracted by vacuuming, in one embodiment, the gas extracted by vacuuming when the mixer is vacuumized is directly introduced into the pebble bed chamber, and then discharged from the bottom of the pebble bed chamber after passing through the pebble bed, and enters the waste gas treatment device. .

In one embodiment, the gas evacuated by vacuuming when the pyrolysis chamber is evacuated is directly introduced into the pebble bed chamber, and then discharged from below the pebble bed chamber after passing through the pebble bed, and enters the waste gas treatment device.

In one embodiment, the inert gas includes: nitrogen.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims (5)

1. a method for reducing the decomposition and volatilization of radioactive waste based on inert gas, for pyrolysis furnace, is characterized in that, comprising: After the radioactive waste is mixed in the mixer, inert gas is introduced into the mixer; The pyrolysis chamber is evacuated after a certain time after the mixing of the radioactive waste in the mixer begins, Pour inert gas into the pyrolysis chamber; After performing the above steps, repeat the steps of evacuating the pyrolysis chamber and rushing inert gas into the pyrolysis chamber after a certain period of time after the radioactive waste is mixed in the mixer, and repeating the steps for a total of 3 times; The oxygen content of the air in the pyrolysis chamber is analyzed by an oxygen analyzer, When the oxygen content in the pyrolysis chamber is lower than the preset value, transferring the radioactive waste in the mixer into the pyrolysis chamber; start pyrolysis; Also include before starting the pyrolysis: Inert gas is introduced into the pebble bed room; Vacuuming the pyrolysis chamber specifically includes: When the pyrolysis chamber is evacuated, the gas extracted by vacuuming is directly introduced into the pebble bed room, and then discharged from the bottom of the pebble bed room after passing through the pebble bed, and enters the waste gas treatment device; Also included after starting pyrolysis: Every preset time; close the channel between the waste gas temporary storage chamber and the pyrolysis chamber, Open the outlet of the exhaust gas temporary storage chamber located in the pebble bed chamber. 2. The method for reducing the decomposition and volatilization of radioactive waste based on an inert gas according to claim 1, further comprising: After the pyrolysis is over, the outlet of the waste gas temporary storage chamber and the channel between the waste gas temporary storage chamber and the pyrolysis chamber are opened; and an inert gas is continuously introduced into the pyrolysis chamber for a period of time. 3. The method for reducing the decomposition and volatilization of radioactive waste based on an inert gas according to claim 1, wherein after the radioactive waste is put into the mixer and before starting to mix, the mixer is evacuated; Start mixing. 4. the method for reducing the decomposing and volatile amount of radioactive waste based on inert gas as claimed in claim 3, is characterized in that, the gas that is evacuated when the mixer is evacuated is directly introduced into the pebble bed chamber, and after the pebble bed is passed through the pebble bed It is discharged from the bottom of the chamber and enters the exhaust gas treatment device. 5. The method for reducing the amount of decomposing and volatilizing radioactive waste based on an inert gas according to claim 1, wherein the inert gas comprises: nitrogen.

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