Radioactive waste supercritical water oxidized nuclide removal reaction device

Abstract

A radioactive waste supercritical water oxidation nuclide removal reaction device comprises a cooling water jacket, a pressure-bearing type reaction cavity is formed in the cooling water jacket, a flow guide cavity is formed in the pressure-bearing type reaction cavity, a nuclide salt removal core area is arranged in the center of the flow guide cavity, and an end cover material inlet area is arranged at the top of the nuclide salt removal core area. Waste heat recovery devices are respectively arranged in the flow guide cavity and the pressure-bearing reaction cavity; in a supercritical water oxidation environment, efficient degradation of radioactive wastes is realized, and nuclides are separated by using the characteristic of extremely low solubility of supercritical water to nuclide salts and the thermal wall adhesion effect of inorganic salts and by adopting a multi-stage filtering method, so that migration of the radionuclide salts is limited in a core area in a reactor, and the radionuclide salts are efficiently degraded. Nuclide contamination of large-size key parts such as a pressure-bearing wall and an end cover of the reactor is avoided, and meanwhile, mechanical devices such as a stirring device and a scraping brush are not additionally arranged in the reactor, so that the minimization of radioactive waste generated after the device is decommissioned is ensured; the method has a remarkable application value in the field of supercritical water oxidation treatment of radioactive wastes.

Description

Technical Field

[0001] The utility model belongs to the technical field of radioactive waste treatment, and particularly relates to a radioactive waste supercritical water oxidation nuclide removal reaction device. Technical Background

[0002] In the process of carbon peak and carbon neutrality, nuclear energy as a low-carbon clean energy is an important choice for my country's energy transformation. With the active, safe and orderly advancement of nuclear power construction, various types of radioactive organic wastes that need to be treated and disposed of have been generated, such as radioactive waste resins, waste protective clothing, waste vacuum pump oil, waste TBP solvents and waste biodegradable protective materials. However, the corresponding waste management work is seriously lagging behind, and the uncertainty of long-term temporary storage and future management of radioactive waste has caused potential safety risks to increase day by day.

[0003] At present, conventional treatment processes mainly include cement solidification, hot super compression, incineration, etc. However, cement solidification has various problems such as volume expansion, organic matter super compression storage process will be decomposed by radiation and cause compression cake to break, and the incineration tail gas treatment system is complicated. In addition, the glass solidification technology has slow progress in substantial engineering due to high operating temperature and complicated exhaust gas treatment system.

[0004] As a cutting-edge organic waste treatment technology, supercritical water oxidation technology has been proven to be highly effective in degrading radioactive waste resins, waste tributyl phosphate (TBP) solvents, waste scintillating fluids, waste vacuum pump oils, and waste plastics used in the nuclear industry. This technology uses the special properties of supercritical water to allow radioactive organic waste and oxidants to undergo a rapid and thorough homogeneous oxidation reaction in supercritical water. At the same time, supercritical water has extremely low solubility for nuclide inorganic salts, which can separate and remove nuclide salts in a supercritical water environment.

[0005] However, for the radioactive nuclide salts in the reaction process, mechanical devices such as mechanical stirring and scraping are usually used to remove them. On the one hand, the mechanical stirring device is unstable under the high temperature and high pressure supercritical water conditions. On the other hand, the nuclide salts will contaminate a large area and a wide range in the reactor, resulting in an increase in radioactive waste after the subsequent decommissioning of the device. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the utility model is to provide a radioactive waste supercritical water oxidation nuclide removal reaction device, which realizes the efficient degradation of radioactive waste in the supercritical water oxidation environment, utilizes the extremely low solubility of supercritical water to nuclide salts, and the hot wall adhesion effect of inorganic salts, and adopts a multi-stage filtration method to separate nuclides, so that the migration of radioactive nuclide salts is confined to the core area in the reactor, avoiding nuclide contamination of the reactor pressure wall and the large volume of key parts of the end cover. At the same time, no additional mechanical devices such as stirring and scraping are set in the reactor to ensure that the generation of radioactive waste after the device is decommissioned is minimized. The reactor also has the functions of low-temperature injection of materials, alcohol co-oxidation, cold wall protection, and waste heat recovery; it provides a practical solution for the treatment of radioactive waste.

[0007] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0008] A radioactive waste supercritical water oxidation nuclide removal reaction device comprises a cooling water jacket 15, wherein a pressure-bearing reaction chamber 10 is arranged in the cooling water jacket 15, a guide chamber 11 is arranged inside the pressure-bearing reaction chamber 10, a nuclide salt removal core area is arranged in the middle of the guide chamber 11, an end cover material inlet area is arranged at the top of the nuclide salt removal core area, and waste heat recovery devices are respectively arranged in the guide chamber 11 and the pressure-bearing reaction chamber 10.

[0009] The nuclide salt removal core area is provided with a nuclide salt induced generation area 19, a nuclide salt generation buffer area 18, a nuclide salt primary filtration area 17 and a nuclide salt multi-stage filtration area 16 in sequence from the inside to the outside; wherein, the top of the nuclide salt induced generation area 19 is respectively connected to the high-temperature supercritical water injection port N1, the low-temperature material inlet N2 and the first oxidant inlet N3 in the middle of the end cover material inlet area; a filter screen 2 with nuclide salt induced crystal rough protrusions is provided between the nuclide salt induced generation area 19 and the nuclide salt generation buffer area 18 outside thereof A guide buffer filter screen 4 with rough protrusions is provided between the nuclide salt generation buffer zone 18 and the nuclide salt primary filtration zone 17 outside it; a fine filter screen block 5 is provided in the nuclide salt primary filtration zone 17; a guide purification filter screen 7 is provided between the nuclide salt primary filtration zone 17 and the nuclide salt multi-stage filtration zone 16 outside it; the outer wall of the nuclide salt multi-stage filtration zone 16 is the core zone guide wall 8; the nuclide salt multi-stage filtration zone 16 is connected to the second oxidant inlet N4 of the end cover material inlet zone; the waste heat recovery device 12 adopts a heat collector.

[0010] The filter screen 2 with rough protrusions for inducing crystallization of radionuclide salt, the flow-guiding buffer filter screen 4 with rough protrusions and the flow-guiding purification filter screen 7 are all provided with a non-porous radionuclide salt collecting bin 6 at the bottom; the rough protrusions include pointed angles or squares.

[0011] A porous medium channel 13 is disposed at the bottom of the side wall of the flow guiding chamber 11 , and the porous medium channel 13 connects the flow guiding chamber 11 with the pressure-bearing reaction chamber 10 .

[0012] The material inlet area of ​​the end cover includes a cover plate 1, a drug adding cartridge 1-1 is arranged in the middle of the cover plate 1, a high-temperature supercritical water injection port N1, a low-temperature material inlet N2, and a first oxidant inlet N3 are respectively opened on the drug adding cartridge 1-1, a sacrificial lining 21 is arranged at the bottom of the cover plate 1, and the cover plate 1 is filled with an insulating filling material 20, and a second oxidant inlet N4 penetrates the cover plate 1 to connect to the radionuclide salt multi-stage filtration area 16.

[0013] A plurality of vertical partitions 3 are provided in the nuclide salt multi-stage filtration zone 16 and at the bottom of the nuclide salt primary filtration zone 17 . One end of the partition 3 is connected to the filtration grid 9 . The filtration grids 9 on adjacent partitions 3 are staggered to form a diversion channel in the nuclide salt multi-stage filtration zone 16 .

[0014] A multi-stage filtration outlet 14 is provided in the middle of the radionuclide salt multi-stage filtration zone 16 , and the bottom of the multi-stage filtration outlet 14 extends to the height of the porous medium channel 13 near the bottom of the guide cavity 11 ; the multi-stage filtration outlet 14 uses a filtration material.

[0015] A cooling water jacket 15 is disposed outside the pressure-bearing reaction chamber 10 . A cooling water inlet N5 is disposed on one side of the upper portion of the cooling water jacket 15 . A cooling water outlet N6 is disposed on the opposite side of the lower portion of the cooling water jacket 15 . A reaction water outlet N7 is disposed on the upper side wall of the pressure-bearing reaction chamber 10 .

[0016] The guide buffer filter screen 4 with rough protrusions is dense at the top and sparse at the bottom, and the particle size of the upper filter particles is not larger than the particle size of the fine filter screen block 5, and the particle size of the lower filter particles is not larger than the particle size of the filter screen 2 with rough protrusions induced by radionuclide salt crystallization.

[0017] The filter screen 2 with nuclide salt induced crystallization rough protrusions, the flow guide buffer filter screen 4, the fine filter screen block 5 and the multi-stage filter outlet 14 are composed of flexible, lightweight and compressible filter screens, and the materials include alloy, asbestos and powder sintered metal.

[0018] The thickness of the fine filter block is adjustable.

[0019] Compared with the prior art, the beneficial effects of the utility model are:

[0020] 1. Effectively separate nuclides in the core area of ​​the reactor. Taking advantage of the extremely low solubility of nuclides in supercritical water and the hot wall adhesion effect, the nuclide salts are removed in the high temperature area of ​​the reactor, and rough protrusions are set to induce the nuclide salts to form and adhere in the core area. At the same time, as the reaction area expands and the size of the nuclide salt particles increases, a buffer area is set to induce the nuclide salts to crystallize and adhere, so as to confine most of the nuclide salts to the core area of ​​the reactor and avoid large-scale contamination of nuclide salts.

[0021] 2. The reactor does not require additional mechanical denuclides such as agitators and scrapers, which avoids the operational failure of mechanical devices such as agitators and scrapers under high temperature and high pressure conditions, making the reactor more stable. In the core area, the nuclide salt is removed by multi-stage and multiple filtration through the density of the filter screen, filtration coupled with gravity sedimentation, etc., without the need for mechanical stirring devices, and is more reliable and safe to operate under high temperature and high pressure conditions.

[0022] 3. It has the function of cold material injection with high-temperature pure supercritical water preheating and radioactive materials without preheating, avoiding the problem of preheating coking and clogging of radioactive materials before entering the reactor; alcohol substances can be mixed with the materials to realize the functions of supercritical water oxidation and alcohol co-oxidation, so that the reaction temperature is higher and the degradation of organic matter is more thorough; cold wall water is used to cool down and protect the high-temperature and high-pressure pressure wall to prevent the reactor pressure wall from overheating; multi-stage waste heat recovery areas are set up to realize energy cascade recovery and utilization, which can ensure the safe, energy-saving, stable and reliable operation of the reactor.

[0023] In summary, the utility model has the advantages of rapid and thorough reaction, excellent volume reduction, less secondary pollution, and energy saving in treating radioactive waste based on supercritical water oxidation technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the utility model.

[0025] Figure 2 This is a partial enlarged view of the core area.

[0026] Among them: 1-cover plate; 1-1-drug adding cylinder; 2-filter screen with rough protrusions for inducing crystallization of radionuclide salt; 3-partition plate; 4-flow guide buffer filter screen with rough protrusions; 5-fine filter screen block; 6-porous radionuclide salt collection bin; 7-flow guide purification filter screen; 8-core area guide wall; 9-filter grid; 10-pressure-bearing reaction chamber; 11-flow guide chamber; 12-waste heat recovery device; 13-porous medium channel; 14-multi-stage filter outlet; 15-cooling water jacket; 16-nuclide salt multi-stage filtration zone; 17-nuclide salt primary filtration zone; 18-nuclide salt generation buffer zone; 19-nuclide salt induced generation zone; 20-insulating filling material; 21-sacrificial lining; N1-high-temperature supercritical water injection port; N2-low-temperature material inlet; N3-first oxidant inlet; N4-second oxidant inlet; N5-cold wall water inlet; N6-cold wall water outlet; N7-reaction water outlet. DETAILED DESCRIPTION

[0027] The implementation modes of the present utility model are described in detail below with reference to the accompanying drawings and embodiments.

[0028] like Figure 1 and Figure 2As shown, a radioactive waste supercritical water oxidation nuclide removal reaction device comprises a cooling water jacket 15, a pressurized reaction chamber 10 is arranged in the cooling water jacket 15, a guide chamber 11 is arranged inside the pressurized reaction chamber 10, a nuclide salt removal core area is arranged in the middle of the guide chamber 11, an end cover material inlet area is arranged on the top of the nuclide salt removal core area, and waste heat recovery devices are respectively arranged in the guide chamber 11 and the pressurized reaction chamber 10.

[0029] The nuclide salt removal core area is provided with a nuclide salt induced generation area 19, a nuclide salt generation buffer area 18, a nuclide salt primary filtration area 17 and a nuclide salt multi-stage filtration area 16 in sequence from the inside to the outside; wherein, the top of the nuclide salt induced generation area 19 is respectively connected to the high-temperature supercritical water injection port N1, the low-temperature material inlet N2 and the first oxidant inlet N3 in the middle of the end cover material inlet area; a filter screen 2 with nuclide salt induced crystal rough protrusions is provided between the nuclide salt induced generation area 19 and the nuclide salt generation buffer area 18 outside thereof A guide buffer filter screen 4 with rough protrusions is provided between the nuclide salt generation buffer zone 18 and the nuclide salt primary filtration zone 17 outside it; a fine filter screen block 5 is provided in the nuclide salt primary filtration zone 17; a guide purification filter screen 7 is provided between the nuclide salt primary filtration zone 17 and the nuclide salt multi-stage filtration zone 16 outside it; the outer wall of the nuclide salt multi-stage filtration zone 16 is the core zone guide wall 8; the nuclide salt multi-stage filtration zone 16 is connected to the second oxidant inlet N4 of the end cover material inlet zone; the waste heat recovery device 12 adopts a heat collector.

[0030] The filter screen 2 with rough protrusions for inducing crystallization of radionuclide salt, the flow-guiding buffer filter screen 4 with rough protrusions and the flow-guiding purification filter screen 7 are all provided with a non-porous radionuclide salt collecting bin 6 at the bottom; the rough protrusions include pointed angles or squares.

[0031] A porous medium channel 13 is disposed at the bottom of the side wall of the flow guiding chamber 11 , and the porous medium channel 13 connects the flow guiding chamber 11 with the pressure-bearing reaction chamber 10 .

[0032] The material inlet area of ​​the end cover also includes a cover plate 1, a drug adding cartridge 1-1 is arranged in the middle of the cover plate 1, a high-temperature supercritical water injection port N1, a low-temperature material inlet N2, and a first oxidant inlet N3 are respectively opened on the drug adding cartridge 1-1, a sacrificial lining 21 is arranged at the bottom of the cover plate 1, and the cover plate 1 is filled with an insulating filling material 20, and the second oxidant inlet N4 penetrates the cover plate 1 to connect to the radionuclide salt multi-stage filtration area 16.

[0033] A plurality of vertical partitions 3 are provided in the nuclide salt multi-stage filtration zone 16 and at the bottom of the nuclide salt primary filtration zone 17 . One end of the partition 3 is connected to the filtration grid 9 . The filtration grids 9 on adjacent partitions 3 are staggered to form a diversion channel in the nuclide salt multi-stage filtration zone 16 .

[0034] A multi-stage filtration outlet 14 is provided in the middle of the radionuclide salt multi-stage filtration zone 16, and the bottom of the multi-stage filtration outlet 14 extends to the height of the porous medium channel 13 near the bottom of the guide cavity 11; the multi-stage filtration outlet 14 adopts filtering material to make the purified reaction fluid flow out evenly and be heated by the waste heat recovery device 12.

[0035] A cooling water jacket 15 is disposed outside the pressure-bearing reaction chamber 10 . A cooling water inlet N5 is disposed on one side of the upper portion of the cooling water jacket 15 . A cooling water outlet N6 is disposed on the opposite side of the lower portion of the cooling water jacket 15 . A reaction water outlet N7 is disposed on the upper side wall of the pressure-bearing reaction chamber 10 .

[0036] The guide buffer filter screen 4 with rough protrusions is dense at the top and sparse at the bottom, and the particle size of the upper filter particles is not larger than the particle size of the fine filter screen block 5, and the particle size of the lower filter particles is not larger than the particle size of the filter screen 2 with rough protrusions induced by radionuclide salt crystallization.

[0037] The filter screen 2 with nuclide salt induced crystallization rough protrusions, the flow guide buffer filter screen 4, the fine filter screen block 5 and the multi-stage filter outlet 14 are composed of flexible, lightweight and compressible filter screens, and the materials include alloy, asbestos and powder sintered metal.

[0038] The thickness of the fine filter block is adjustable.

[0039] The working principle of the utility model is:

[0040] According to the above structure, supercritical water, oxidant and low temperature material mixed with alcohol are respectively injected from the material inlet area of ​​the end cover, mixed in the induced generation area 19 and violent oxidation reaction occurs, organic matter is efficiently degraded, and at the same time, the nuclide salt is attached to the filter screen 2 with rough protrusions for nuclide salt induction crystallization due to its low solubility in supercritical water and the hot wall adhesion effect. After that, the reaction fluid and the nuclide salt continue to pass through the diversion buffer filter screen 4 with rough protrusions, and most of the nuclide salt is intercepted. At the same time, the reaction fluid and the remaining nuclide salt enter the nuclide salt primary filtration area 17 through the diversion effect, and are further purified under the action of the fine filter block 5, and then enter the multi-stage filtration area for deep treatment; the unattached nuclide salt is collected by the non-porous nuclide salt collection bin 6 of each level; after diversion, gravity sedimentation and multi-stage filtration, the remaining nuclide salt is intercepted by the multi-stage filter screen. After purification, the reaction fluid passes through the filter screen wall of the multi-stage filtration outlet 14, the diversion chamber 11 and the pressure-bearing reaction chamber 10, and the waste heat is recovered and utilized, and finally discharged from the reactor from the outlet N7; the filter screens at each level are replaced according to the use requirements and conditions during operation. While realizing the efficient degradation of radioactive waste in the supercritical water oxidation environment, the nuclides are separated by a multi-stage filtration method by utilizing the extremely low solubility of supercritical water for nuclide salts and the hot wall adhesion effect of inorganic salts, so that the migration of radioactive nuclide salts is limited to the core area of ​​the reactor, avoiding nuclide contamination of large-volume key parts such as the pressure-bearing wall and end cover of the reactor; the reactor also has the functions of low-temperature injection of materials, alcohol co-oxidation, cold wall protection, and waste heat recovery.

[0041] In summary, based on the problems existing in traditional radioactive waste treatment methods, the utility model proposes a radioactive waste supercritical water oxidation nuclide removal reactor, which can achieve efficient degradation of radioactive waste and efficient collection of radioactive nuclide salts in a small range in the reactor, without the need for additional mechanical devices such as stirring and scraping, to ensure that the device generates minimal radioactive waste after decommissioning. This achieves inorganic reduction of radioactive waste, which has important application significance for actual radioactive waste treatment.

Claims

1. A radioactive waste supercritical water oxidation nuclide removal reaction device, comprising a cooling water jacket (15), characterized in that: A pressure-bearing reaction chamber (10) is arranged in the cooling water jacket (15), a flow guide chamber (11) is arranged inside the pressure-bearing reaction chamber (10), a nuclide salt removal core area is arranged in the middle of the flow guide chamber (11), an end cover material inlet area is arranged at the top of the nuclide salt removal core area, and a waste heat recovery device (12) is arranged in the flow guide chamber (11) and the pressure-bearing reaction chamber (10), respectively.

2. The radioactive waste supercritical water oxidation nuclide removal reaction device according to claim 1 is characterized in that: The nuclide salt removal core zone is provided with a nuclide salt induced generation zone (19), a nuclide salt generation buffer zone (18), a nuclide salt primary filtration zone (17) and a nuclide salt multi-stage filtration zone (16) in sequence from the inside to the outside; wherein the top of the nuclide salt induced generation zone (19) is respectively connected to a high-temperature supercritical water injection port (N1), a low-temperature material inlet (N2) and a first oxidant inlet (N3) in the middle of the end cover material inlet zone; a filter screen (2) with nuclide salt induced crystallization rough protrusions is provided between the nuclide salt induced generation zone (19) and the nuclide salt generation buffer zone (18) outside thereof; A flow guiding buffer filter (4) with rough protrusions is provided between the nuclide salt generation buffer zone (18) and the nuclide salt primary filtration zone (17) outside the nuclide salt; a fine filter block (5) is provided in the nuclide salt primary filtration zone (17); a flow guiding purification filter (7) is provided between the nuclide salt primary filtration zone (17) and the nuclide salt multi-stage filtration zone (16) outside the nuclide salt; the outer wall of the nuclide salt multi-stage filtration zone (16) is a core zone flow guiding wall (8); the nuclide salt multi-stage filtration zone (16) is connected to the second oxidant inlet (N4) of the end cover material inlet zone; and the waste heat recovery device (12) adopts a heat collector.

3. The radioactive waste supercritical water oxidation nuclide removal reaction device according to claim 2, characterized in that: The filter screen with nuclide salt induced crystallization rough protrusions (2), the flow guiding buffer filter screen with rough protrusions (4) and the flow guiding purification filter screen (7) are all provided with a non-porous nuclide salt collection bin (6) at the bottom; the rough protrusions include pointed angles or squares.

4. The radioactive waste supercritical water oxidation nuclide removal reaction device according to claim 2, characterized in that: A porous medium channel (13) is provided at the bottom of the side wall of the flow guiding chamber (11), and the porous medium channel (13) communicates with the flow guiding chamber (11) and the pressure-bearing reaction chamber (10).

5. The radioactive waste supercritical water oxidation nuclide removal reaction device according to claim 1, characterized in that: The end cover material inlet area comprises a cover plate (1), a drug adding cartridge (1-1) is arranged in the middle of the cover plate (1), a high temperature supercritical water injection port (N1), a low temperature material inlet (N2), and a first oxidant inlet (N3) are respectively opened on the drug adding cartridge (1-1), a sacrificial lining (21) is arranged at the bottom of the cover plate (1), a heat insulating filling material (20) is filled in the cover plate (1), and a second oxidant inlet (N4) penetrates the cover plate (1) and is connected to a radionuclide salt multi-stage filtration area (16).

6. The radioactive waste supercritical water oxidation nuclide removal reaction device according to claim 2, characterized in that: A plurality of vertical partitions (3) are provided in the nuclide salt multi-stage filtration zone (16) and at the bottom of the nuclide salt primary filtration zone (17); one end of the partition (3) is connected to a filtration grid (9); and the filtration grids (9) on adjacent partitions (3) are arranged in a staggered manner, thereby forming a guide channel in the nuclide salt multi-stage filtration zone (16).

7. A radioactive waste supercritical water oxidation nuclide removal reaction device according to claim 2, 5 or 6, characterized in that: A multi-stage filtering outlet (14) is provided in the middle of the radionuclide salt multi-stage filtering zone (16), and the bottom of the multi-stage filtering outlet (14) extends to the height of the porous medium channel (13) near the bottom of the guide cavity (11); the multi-stage filtering outlet (14) adopts filtering material.

8. The radioactive waste supercritical water oxidation nuclide removal reaction device according to claim 1, characterized in that: A cooling water jacket (15) is arranged outside the pressure-bearing reaction chamber (10), a cooling water inlet (N5) is arranged on one side of the upper part of the cooling water jacket (15), a cooling water outlet (N6) is arranged on the opposite side of the lower part of the cooling water jacket (15), and a reaction water outlet (N7) is arranged on the upper side wall of the pressure-bearing reaction chamber (10).

9. The radioactive waste supercritical water oxidation nuclide removal reaction device according to claim 2, characterized in that: The guide buffer filter screen (4) with rough protrusions is dense at the top and sparse at the bottom, and the particle size of the upper filtered particles is not larger than the particle size of the fine filter screen block (5), and the particle size of the lower filtered particles is not larger than the particle size of the filter screen (2) with rough protrusions induced by radionuclide salt crystallization.

10. The radioactive waste supercritical water oxidation nuclide removal reaction device according to claim 2, characterized in that: The filter screen with nuclide salt induced crystallization rough protrusions (2), the flow guide buffer filter screen (4), the fine filter screen block (5) and the multi-stage filter outlet (14) are composed of flexible, lightweight and compressible filter screens, and the materials include alloy, asbestos and powder sintered metal.

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