CN114321941A

CN114321941A - Oxygen-controlled incinerator for radioactive combustible waste

Info

Publication number: CN114321941A
Application number: CN202111475829.3A
Authority: CN
Inventors: 徐卫; 崔晗; 杨利国; 王鹏; 郑博文; 褚浩然; 李晓海; 张晓斌; 阮佳晟; 张禹; 李串莲; 贾成明; 杨丽莉; 李磊; 佟晓磊; 要雅姝; 胡磊
Original assignee: China Institute for Radiation Protection
Current assignee: China Institute for Radiation Protection
Priority date: 2021-12-06
Filing date: 2021-12-06
Publication date: 2022-04-12

Abstract

The invention relates to an oxygen-controlled incinerator for radioactive combustible waste, which comprises an upper furnace body (1) and a lower furnace body (2), wherein after the upper furnace body (1) and the lower furnace body (2) are sequentially arranged and connected from top to bottom, inner shells of the upper furnace body (1) and the lower furnace body (2) jointly form a hearth of the incinerator. The incinerator uses the air cylinder to push the turning plate to seal the feeding process, uses the spiral grate to perform stirring and ash discharging operations, simplifies pipelines in a waste heat recovery mode, and prolongs the service life of the grate at high temperature through the air-cooled grate structure, so that the height of the incinerator is greatly reduced, the incinerator can be used for optimizing the layout of a mobile radioactive waste incineration device, and the treatment cost of radioactive combustible waste is favorably reduced.

Description

Oxygen-controlled incinerator for radioactive combustible waste

Technical Field

The invention belongs to the field of radiation protection, and particularly relates to an oxygen-controlled incinerator for radioactive combustible waste.

Background

Domestic radioactive combustible waste has urgent volume reduction treatment requirements. Taking a nuclear power station as an example, the management target value of radioactive wastes generated by a single unit in the current domestic nuclear power station is 50m³And a, the actual production amount is far higher than the value, and the waste needs to be further reduced in volume and weight to meet the requirement. Most of the wastes are radioactive combustible wastes such as protective clothing, gloves and adsorption resin, and are mostly stored in a temporary storage warehouse at present, and part of the wastes exceeds the temporary storage period, so that the fire risk exists, and the pressure in the aspects of storage capacity, maintenance, supervision and the like is huge.

The mobile incineration is an ideal scheme for treating the combustible waste of the nuclear facilities in China at present; at present, volume reduction technologies adopted by nuclear facilities in China for radioactive combustible waste comprise overpressure, cement solidification, incineration and the like; wherein the volume reduction of the overpressure to the combustible technical waste is low and the compression has rebound; the cement solidification is a compatibilization treatment technology; in contrast, incineration treatment can greatly reduce the volume of waste, and is an international general technology for treating radioactive solid combustible waste; at present, the number of domestic incineration stations is small, most nuclear facilities treat combustible solid wastes and need long-distance transportation post-treatment, and the treatment cost is greatly increased; therefore, the requirement of adding radioactive waste incineration stations is urgent, but the procedure is strict in China and the construction period is long.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides an oxygen-controlled incinerator for radioactive combustible waste, which uses a spiral grate to stir and discharge ash, so that the ash is transversely discharged, the whole height of the device does not contain the height of an ash box, simultaneously, a pipeline is simplified in a waste heat recovery mode, and the service life of the grate at high temperature is prolonged through an air-cooled grate structure, so that the height of the incinerator is greatly reduced, the oxygen-controlled incinerator can be used for optimizing the layout of a mobile radioactive waste incinerator, and the treatment cost of the radioactive combustible waste is favorably reduced.

In order to achieve the above purposes, the invention adopts the technical scheme that: the utility model provides a furnace is burnt to radioactive combustible waste matter accuse oxygen includes furnace body and lower furnace body, goes up the furnace body and sets gradually from top to bottom with lower furnace body, goes up furnace body 1 and constitutes the furnace chamber of burning furnace jointly with the interior casing of lower furnace body 2 after connecting.

Further, the upper furnace body comprises a feeding bin, a feeding plate turning mechanism, a feeding mechanism, a water-cooling plate turning mechanism and an upper furnace inner shell; the export of feed bin and the access connection of last furnace inner shell, feeding panel turnover mechanism installs the feed inlet department at feed bin upper surface, feeding mechanism installs in the feed bin, water-cooling panel turnover mechanism installs the import department at last furnace inner shell.

Further, the plate turnover mechanism comprises a feeding cover plate and a cover plate cylinder; the feeding cover plate is horizontally arranged at an opening on the upper surface of the feeding bin, and a turnover shaft of the feeding cover plate is connected with the cover plate cylinder.

Further, the feeding mechanism comprises a chain plate conveyor and a chain plate conveyor driving motor; the chain scraper conveyor is installed in the feeding bin, the starting end of the chain scraper conveyor is located below the feeding hole of the feeding bin, the tail end of the chain scraper conveyor is located at the outlet of the feeding bin, and a driving shaft of the chain scraper conveyor is fixedly connected with a motor shaft of a driving motor of the chain scraper conveyor through a coupling.

Further, the water-cooling turning plate mechanism comprises a water-cooling turning plate, a top cylinder and a driving frame; the water-cooling turns over the import department of board vertical installation casing in last furnace, and top cylinder fixed mounting turns over the upper surface of board at the upper part of the body, and the piston rod of top cylinder turns over the upset hub connection of board through drive frame and water-cooling, and the water-cooling turns over the inside cavity that is of board, and the both sides that the board was turned over to the water-cooling are equipped with water-cooling respectively and turn over board cooling water inlet and water-cooling and turn over board cooling water outlet.

Furthermore, the upper surface of the upper furnace body is provided with an observation mirror, the side surface of the upper furnace body is provided with an upper hearth temperature measuring port, and the flue gas outlet of the upper furnace body is provided with a flue gas outlet temperature measuring port and a flue gas outlet pressure measuring port.

Furthermore, a water-cooling jacket is arranged in the side wall of the upper hearth inner shell, a cooling water inlet is formed in the bottom of the water-cooling jacket and communicated with the water-cooling jacket, a cooling water outlet and an emptying valve connector are formed in the upper surface of the upper hearth inner shell, and the cooling water outlet and the emptying valve connector are communicated with the water-cooling jacket.

Further, the lower furnace body comprises an ash bin, a lower hearth inner shell, a primary air pipe, a rotary grate, a grate bearing mechanism and an inner shell supporting seat; the lower hearth inner shell is arranged on an inner shell supporting seat, an outlet at the lower part of the lower hearth inner shell is connected with an inlet of an ash bin, a rotary furnace is horizontally arranged at the bottom in the lower hearth inner shell, the left end of a rotary grate is connected with a motor shaft of a driving motor through a grate bearing mechanism, the right end of the rotary grate is positioned in the ash bin, a primary air pipe is tightly attached to the inner side of a conical section of the lower hearth inner shell, the side wall of the lower hearth inner shell is provided with an air cooling jacket, the outer wall of the lower furnace body is provided with an air inlet and an air outlet, the air inlet and the air outlet are both communicated with the air cooling jacket, and the outer wall of the lower furnace body is also provided with a burner interface (penetrating through the air cooling jacket); one end of the spiral grate is welded with a shaft head and is provided with a cooling air inlet communicated with the air cooling jacket, and the air cooling outlet end of the spiral grate is arranged in the ash box. An air cooling jacket is arranged in the hollow shaft, and cooling air cools the spiral grate in the hollow shaft and the spiral air cooling jacket. Rectangular holes are formed in the front end and the rear end of the connecting part of the spiral air cooling jacket and the hollow shaft along the spiral position, and circulation of cooling air from the spiral jacket is guaranteed. Cooling air enters the spiral grate from an air inlet hole with the front end vertical to the shaft, and is spirally discharged from an air cooling outlet of the spiral grate after passing through the hollow shaft and the jacket.

Furthermore, the side wall of the lower furnace body is provided with a secondary air inlet, and the side surface of the lower furnace body is provided with a temperature measuring pipe.

Furthermore, a viewing window is arranged on the side surface of the ash bin, a standby air outlet is arranged on the upper surface of the ash bin, and an ash discharge port is formed in the end surface of the right end of the ash bin.

The invention has the beneficial technical effects that:

(1) the invention uses the spiral grate to stir and discharge ash, thereby transversely discharging the ash and reducing the height of the incinerator. The upper furnace body uses water cooling to ensure the structural strength of the gas under high-temperature combustion; the lower furnace body uses air cooling to recover heat and supply combustion-supporting air. Meanwhile, the feeding device uses a chain plate conveyor to replace an air cylinder, so that the space requirement of the equipment is reduced on the premise of ensuring the feeding speed; a partition plate between the feeding bin and the hearth is driven in a rotating turnover plate mode, so that the air cylinders are horizontally arranged to reduce the height of the equipment;

(2) the lower furnace body of the invention carries out waste heat recovery: the lower furnace body uses an air cooling jacket, and the heated cooling air is used as combustion-supporting air and is sent into a hearth;

(3) the feeding device of the invention uses the water-cooling turning plate and the chain plate conveyor, so that the requirement on equipment space is smaller;

(4) the fire grate of the invention adopts a spiral air cooling design: the spiral grate transversely discharges incineration ash to the ash box, the air cooling jacket prolongs the service life of the grate in a high-temperature environment, and high-temperature combustion-supporting air returned to the hearth from the air cooling outlet of the grate can reduce the adhesion and coking conditions of the grate.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a front view of the upper furnace body;

FIG. 3 is a top view of the upper furnace body;

FIG. 4 is a front view of the lower furnace body;

FIG. 5 is a side view of the lower furnace body;

fig. 6 is a schematic view of a rotary grate.

In the figure:

1-upper furnace body, 1-1-observation mirror, 1-3-temperature measuring port at flue gas outlet, 1-4-pressure measuring port at flue gas outlet, 2-lower furnace body, 2-1-air inlet, 2-2-air outlet, 2-3-burner interface, 3-feeding bin, 4-feeding cover plate, 4-1-cover plate cylinder, 5-chain plate conveyor, 5-1-chain plate conveyor driving motor, 6-water cooling turning plate, 6-1-water cooling turning plate cooling water inlet, 6-2-water cooling turning plate cooling water outlet, 7-top cylinder, 7-1-driving frame, 8-water cooling jacket, 8-1-cooling water inlet and 8-2-cooling water outlet, 8-3-an emptying valve connector, 9-an upper hearth inner shell, 10-an air cooling jacket, 11-an ash bin, 11-1-a sight glass window, 11-2-an ash discharge port, 11-3-a spare flue gas outlet, 12-a lower hearth inner shell, 13-a spiral grate, 13-1-a shaft head, 13-2-a spiral grate air cooling outlet, 13-3-a hollow shaft, 13-4-a spiral cyclone cooling jacket, 14-a grate bearing mechanism and 15-an inner shell supporting seat.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

As shown in figure 1, the invention provides an oxygen-controlled incinerator for radioactive combustible waste, which comprises an upper furnace body 1 and a lower furnace body 2, wherein the upper furnace body 1 and the lower furnace body 2 are sequentially arranged from top to bottom, and inner shells connected with the upper furnace body 1 and the lower furnace body 2 jointly form a hearth of the incinerator.

Based on this, as shown in fig. 2 and 3, the upper furnace body 1 comprises a feeding bin 3, a feeding plate turnover mechanism, a feeding mechanism, a water-cooling plate turnover mechanism and an upper hearth inner shell 9; the export of feed bin 3 and the access connection of last furnace inner shell 9, the feeding turns over the board mechanism and installs the feed inlet department at feed bin 3 upper surface, feeding mechanism installs in feed bin 3, water-cooling turns over board mechanism and installs the import department of last furnace inner shell 9.

The plate turnover mechanism comprises a feeding cover plate 4 and a cover plate cylinder 4-1; the feeding cover plate 4 is horizontally arranged at an opening on the upper surface of the feeding bin 3, and the turnover shaft of the feeding cover plate 4 is connected with the cover plate cylinder 4-1. The feeding cover plate is driven by a lateral cover plate cylinder 4-1.

The feeding mechanism comprises a chain plate conveyor 5 and a chain plate conveyor driving motor 5-1; the chain scraper conveyor 5 is installed in the feeding bin 3, the starting end of the chain scraper conveyor 5 is located below the feeding hole of the feeding bin 3, the tail end of the chain scraper conveyor 5 is located at the outlet of the feeding bin 3, and the driving shaft of the chain scraper conveyor 5 is fixedly connected with the motor shaft of the driving motor 5-1 of the chain scraper conveyor through a coupling. The chain plate conveyor is driven by an external motor 5-1.

The water-cooling turning plate mechanism comprises a water-cooling turning plate 6, a top cylinder 7 and a driving frame 7-1; the water-cooling turning plate 6 is vertically arranged at an inlet of a shell 9 in the upper hearth, the top cylinder 7 is fixedly arranged on the upper surface of the upper body 1, a piston rod of the top cylinder 7 is connected with a turning shaft of the water-cooling turning plate 6 through a driving frame 7-1, a cavity is arranged inside the water-cooling turning plate 6, and a water-cooling turning plate cooling water inlet 6-1 and a water-cooling turning plate cooling water outlet 6-2 are respectively arranged on two sides of the water-cooling turning plate 6. The interface of the feeding bin 3 and the inner shell 9 of the upper hearth is separated by a water-cooling turning plate 6, the water-cooling turning plate is driven by a cylinder 7 at the top of the upper hearth, and cooling water is supplied to a cooling water inlet 6-1 of the water-cooling turning plate and a cooling water outlet 6-2 of the water-cooling turning plate from the shaft ends at the two sides of the turning plate.

The upper surface of the upper furnace body 1 is provided with an observation mirror 1-1, the outlet of the upper furnace body 1 is provided with an upper hearth temperature measuring port (penetrating through a water cooling jacket), and the flue gas outlet of the upper furnace body 9 is provided with a flue gas outlet temperature measuring port 1-3 and a flue gas outlet pressure measuring port 1-4.

A water-cooling jacket 8 is arranged in the side wall of the upper hearth inner shell 9, a cooling water inlet 8-1 is arranged at the bottom of the water-cooling jacket 8, the cooling water inlet 8-1 is communicated with the water-cooling jacket 8, a cooling water outlet 8-2 and an emptying valve interface 8-3 are arranged on the upper surface of the water-cooling jacket 8, and the cooling water outlet 8-2 and the emptying valve interface 8-3 are both communicated with the water-cooling jacket 8.

The upper furnace body is provided with a water cooling jacket 8, cooling water enters from a cooling water inlet 8-1 and flows out from a cooling water outlet 8-2, and the upper part of the upper furnace body is provided with an interface of an emptying valve 8-3 for exhausting air during water injection.

Based on this, as shown in fig. 4 and 5, the lower furnace body 2 comprises an ash bin 11, a lower furnace inner shell 12, a primary air pipe 12-1, a rotary grate 13, a grate bearing mechanism 14 and an inner shell support seat 15; the lower hearth inner shell 12 is arranged on an inner shell support seat 15, an outlet at the lower part of the lower hearth inner shell 12 is connected with an inlet of an ash bin 11, a rotary grate 13 is horizontally arranged at the bottom in the lower hearth inner shell 12, one end of the rotary grate 13 is connected with a motor shaft of a driving motor through a grate bearing mechanism 14, the other end of the rotary grate 13 is positioned in the ash bin 11, a primary air pipe 12-1 is tightly attached to the inner side of a conical section of the lower hearth inner shell 12, an air cooling jacket 10 is arranged on the side wall of the lower hearth inner shell 12, an air inlet 2-1 and an air outlet 2-2 are arranged on the outer wall of the lower furnace body 2, the air inlet 2-1 and the air outlet 2-2 are both communicated with the air cooling jacket 10, and a burner interface 2-3 is also arranged on the lower furnace body 12.

The spiral grate 13 is arranged at the bottom of the inner shell 12 of the lower hearth and is supported by an inner shell supporting seat 15 and a grate bearing mechanism 14; the fire grate bearing mechanism 14 comprises a bearing, a gland and the like, the front end of the fire grate bearing mechanism is connected with a three-phase motor through a coupler, and the rotating speed and the rotating direction can be adjusted by a frequency converter.

The lower furnace body 2 is provided with an air-cooled jacket 10, an air inlet 2-1 is arranged below the jacket, an air outlet 2-2 is arranged on the right side, and an inner shell supporting seat 15 is arranged at the bottom of the lower furnace body 2.

The side of the lower furnace body is provided with a burner interface 2-3, and the burner is obliquely inserted into the lower furnace body.

The ash bin 11 is welded below one side of the lower furnace body; the bottom of the inner shell 12 of the lower hearth is arc-shaped and is jointed with the spiral grate 13, and when in use, the materials and the incineration ash spiral move back and forth with the inner shell under the action of friction force, thereby realizing the effects of ash discharge and stirring.

A plurality of primary air inlet pipes 12-1 are distributed at the lower part of the inner shell 12 of the lower hearth, so that the air is uniformly distributed in the incineration of the materials, and the full incineration is ensured; the middle part is provided with a secondary air inlet 12-2, and the inlet air comes from cooling air after being heated in an air cooling jacket, so that the combustion effect can be improved and the heat utilization rate can be improved. Meanwhile, a temperature measuring tube 12-3 is arranged to measure the temperature of the lower hearth.

The side wall of the inner shell 12 of the lower hearth is provided with a secondary air inlet 12-2, and the lower furnace body 2 is provided with a temperature measuring tube 12-3 (penetrating through the air cooling jacket 10).

The side surface of the ash bin 11 is provided with a sight glass window 11-1, the upper surface is provided with a standby air outlet 11-3, and the right end surface of the ash bin 11 is provided with an ash discharge port 11-2.

In addition, as shown in fig. 6, the spiral grate 13 comprises a shaft head 13-1, a hollow shaft 13-3 and a spiral cold air jacket 13-4, the shaft head 13-1 is welded at one end of the spiral grate 13, a cooling air inlet is communicated with the air cooling jacket, and an air cooling outlet 13-2 end of the spiral grate is arranged in the ash bin. An air cooling jacket is arranged in the hollow shaft 13-3, and cooling air and the spiral air cooling jacket 13-4 cool the spiral grate. Rectangular holes are formed at the front and rear tail ends of the connecting part of the spiral air cooling jacket 13-4 and the hollow shaft 13-3 along spiral positions, so that cooling air is ensured to circulate from the spiral jacket. Cooling air enters the spiral grate from an air inlet hole with the front end vertical to the shaft, and is spirally discharged from an air cooling outlet 13-2 of the spiral grate after passing through the hollow shaft and the jacket.

The method is realized in such a way that radioactive wastes (including but not limited to nuclear power technical wastes, waste rubber and waste ion exchange resin) are packaged and prepared, when feeding is needed, a feeding cover plate 4 is opened to enable the packaged materials to fall onto a chain plate conveyor 5 of a feeding bin 3, the feeding cover plate 4 is closed to keep sealing, then a water-cooling turning plate 6 is opened, the chain plate conveyor 5 rotates to enable the materials to fall onto a spiral grate 13 in a hearth, and the water-cooling turning plate 6 is closed. After the packed radioactive waste enters the lower hearth inner shell 12, the added material is ignited by the flame of the burner or the burning material. During the combustion process, the spiral grate 13 realizes the stirring of the materials through the interaction of forward and reverse rotation and the inner shell 12 of the lower hearth. Incineration ash generated after a certain material is incinerated is transversely discharged into an ash bin 12 through a spiral grate 13, and meanwhile, high-temperature combustion-supporting air sent back to a hearth through an air cooling outlet 13-2 of the spiral grate reduces the melting leakage of the plastic material;

meanwhile, the upper furnace body 1 is cooled by using a water cooling jacket 8, the lower furnace body is cooled by using an air cooling jacket 10, and the heated cooling air is divided into three paths and used as preheated combustion-supporting air to enter a hearth;

1. the pyrolysis gas flows out from the air cooling jacket 10 to the air outlet 2-2, then passes through other pipelines and valves, enters the inner shell 12 of the lower hearth from the secondary air inlet 12-2, and is fully combusted

2. 6 primary air inlet pipes 12-1 connected with an inner shell 12 of a lower hearth from an air cooling jacket 10 directly enter the hearth, and air is fed from the bottom of the material to pyrolyze and fully combust the material;

3. after flowing out from the air-cooled outlet 13-2 of the spiral grate, the ash enters the inner shell 12 of the lower hearth from the ash discharge port, so that the discharged incineration ash is completely combusted, the residual carbon content is low, and the bonding of slag on the spiral grate 13 is reduced.

The oxygen-controlled incinerator for radioactive combustible waste according to the present invention is not limited to the above-mentioned specific embodiments, and those skilled in the art can derive other embodiments according to the technical solution of the present invention, and also fall within the technical innovation scope of the present invention.

Claims

1. An oxygen-controlled incinerator for radioactive combustible waste, which is characterized in that: the utility model provides a furnace is burnt to radioactive combustible waste matter accuse oxygen includes furnace body (1) and lower furnace body (2), goes up furnace body (1) and sets gradually from top to bottom with lower furnace body (2), connects thick furnace body (1) and constitutes the furnace of burning furnace jointly with the interior casing of lower furnace body (2).

2. An oxygen-controlled incinerator for radioactive combustible waste as claimed in claim 1 wherein: the upper furnace body (1) comprises a feeding bin (3), a feeding plate turning mechanism, a feeding mechanism, a water-cooling plate turning mechanism and an upper hearth inner shell (9); the export of feeding storehouse (3) and the access connection of interior casing of last furnace (9), the feeding turns over the board mechanism and installs the feed inlet department at feeding storehouse (3) upper surface, feeding mechanism installs in feeding storehouse (3), the water-cooling turns over the board mechanism and installs the import department of interior casing (9) in last furnace.

3. An oxygen-controlled incinerator for radioactive combustible waste as claimed in claim 2 wherein: the plate turnover mechanism comprises a feeding cover plate (4) and a cover plate cylinder (4-1); the feeding cover plate (4) is horizontally arranged at an opening on the upper surface of the feeding bin (3), and a turnover shaft of the feeding cover plate (4) is connected with the cover plate cylinder (4-1).

4. An oxygen-controlled incinerator for radioactive combustible waste as claimed in claim 2 wherein: the feeding mechanism comprises a chain plate conveyor (5) and a chain plate conveyor driving motor (5-1); the chain plate conveyor (5) is installed in the feeding bin (3), the starting end of the chain plate conveyor (5) is located below the feeding hole of the feeding bin (3), the tail end of the chain plate conveyor (5) is located at the outlet of the feeding bin (3), and a driving shaft of the chain plate conveyor (5) is fixedly connected with a motor shaft of a driving motor (5-1) of the chain plate conveyor through a coupling.

5. An oxygen-controlled incinerator for radioactive combustible waste as claimed in claim 2 wherein: the water-cooling turning plate mechanism comprises a water-cooling turning plate (6), a top cylinder (7) and a driving frame (7-1); the water-cooling turning plate (6) is vertically arranged at the inlet of the shell (9) in the upper hearth, the top cylinder (7) is fixedly arranged on the upper surface of the upper furnace body (1), a piston rod of the top cylinder (7) is connected with a turning shaft of the water-cooling turning plate (6) through a driving frame (7-1), a cavity is formed in the water-cooling turning plate (6), and a water-cooling turning plate cooling water inlet (6-1) and a water-cooling turning plate cooling water outlet (6-2) are respectively arranged on two sides of the water-cooling turning plate (6).

6. An oxygen-controlled incinerator for radioactive combustible waste as claimed in claim 2 wherein: an observation mirror (1-1) is arranged on the upper surface of the upper hearth water-cooling jacket (8), an upper hearth temperature measuring port is arranged on the side of the upper furnace body (1), and a flue gas outlet of the upper furnace body (1) is provided with a flue gas outlet temperature measuring port (1-3) and a flue gas outlet pressure measuring port (1-4).

7. An oxygen-controlled incinerator for radioactive combustible waste as claimed in claim 2 wherein: a water-cooling jacket (8) is arranged in the inner wall of the upper furnace body (1), a cooling water inlet (8-1) is formed in the bottom of the water-cooling jacket (8), the cooling water inlet (8-1) is communicated with the water-cooling jacket (8), a cooling water outlet (8-2) and an emptying valve connector (8-3) are formed in the upper surface of the water-cooling jacket (8), and the cooling water outlet (8-2) and the emptying valve connector (8-3) are both communicated with the water-cooling jacket (8).

8. The oxygen-controlled incinerator for radioactive combustible waste according to claim 1, characterized in that: the lower furnace body (2) comprises an ash bin (11), a lower hearth inner shell (12), a primary air pipe (12-1), a rotary grate (13), a grate bearing mechanism (14) and an inner shell supporting seat (15); the lower hearth inner shell (12) is arranged on an inner shell supporting seat (15), an outlet at the lower part of the lower hearth inner shell (12) is connected with an inlet of an ash bin (11), a rotary grate (13) is horizontally arranged at the bottom in the lower hearth inner shell (12), one end of the rotary grate (13) is connected with a motor shaft of a driving motor through a grate bearing mechanism (14), the other end of the rotary grate (13) is positioned in the ash bin (11), a primary air pipe (12-1) is tightly attached to the inner side of a conical section of the lower hearth inner shell (12), an air cooling jacket (10) is arranged on the side wall of the lower hearth inner shell (12), an air inlet (2-1) and an air outlet (2-2) are arranged on the outer wall of the air cooling jacket (10), the air inlet (2-1) and the air outlet (2-2) are both communicated with the air cooling jacket (10), and a burner interface (2-3) is also arranged on the outer wall of the lower furnace body (2); one end of the spiral grate (13) is welded with a shaft head (13-1) and is provided with a cooling air inlet communicated with the air cooling jacket, the air cooling outlet (13-2) of the spiral grate is arranged in the ash box, the air cooling jacket is arranged in the ash box, cooling air is arranged in the hollow shaft (13-3) and is cooled in the spiral air cooling jacket (13-4), rectangular holes are formed in the front end and the rear end of the connecting part of the spiral air cooling jacket (13-4) and the hollow shaft (13-3) along spiral positions to ensure that the cooling air circulates from the spiral jacket, the cooling air enters the spiral grate from an air inlet hole with the front end perpendicular to the shaft, and is discharged from the air cooling outlet (13-2) of the spiral grate after being spirally wound by the hollow shaft and the jacket.

9. The oxygen-controlled incinerator for radioactive combustible waste as claimed in claim 8, wherein: the side wall of the lower furnace body (2) is provided with a secondary air inlet (12-2), and a temperature measuring pipe (12-3) is inserted on the lower furnace body (2).

10. The oxygen-controlled incinerator for radioactive combustible waste as claimed in claim 8, wherein: a sight glass window (11-1) is arranged on the side surface of the ash bin (11), a standby air outlet (11-3) is arranged on the upper surface of the ash bin (11), and an ash discharge port (11-2) is arranged on the end surface of the right end of the ash bin (11).