Uranyl nitrate solution reactor passive hydrogen-oxygen recombiner

Abstract

The invention provides a uranyl nitrate solution reactor passive hydrogen-oxygen recombiner, and belongs to the technical field of medical isotope reactors. The device comprises a device shell with one closed end. A gas inlet is formed in the open end of the device shell; an inlet heater communicated with the gas inlet is arranged in the device shell, and the other end of the inlet heater is sequentially connected with a front honeycomb catalyst and a rear honeycomb catalyst; a certain space is reserved between the side walls of the inlet heater, the front honeycomb catalyst and the rear honeycomb catalyst and the inner wall of the device shell to serve as a gas channel; a flow guide plate is arranged on the side wall of the tail part of the rear honeycomb catalyst, and a certain distance is reserved between the flow guide plate and the inner wall of the device shell; and a gas outlet communicated with the space is formed in one side of the end part of the device shell. The uranyl nitrate solution reactor passive hydrogen-oxygen recombiner provided by the invention can ensure safe and stable operation of the reactor, and is high in integration degree, simple in system structure and convenient to overhaul and maintain.

Description

Technical Field

[0001] This invention relates to the field of medical isotope reactor technology, and particularly to a passive hydrogen-oxygen recombiner for a uranyl nitrate solution reactor. Background Technology

[0002] The medical isotope test reactor uses liquid fuel for nuclear fission reactions. Uranium fission occurs in solution, and the fission fragments have high kinetic energy. These fragments bombard water, causing water molecules to decompose into hydrogen and oxygen, while simultaneously producing large amounts of N2 and NO through the decomposition of HNO3. x The reactor produces gases and radioactive nuclides (such as I2, Kr, and Xe). In particular, the hydrogen production from fission is very high; a 200kW medical isotope test reactor produces 1.0 NL / s of hydrogen. Furthermore, the amount of hydrogen-oxygen recombination in the reverse reaction is very small at 70℃–80℃. Therefore, this portion of hydrogen and oxygen gas must be carried out of the reactor core via a gas carrier (a nitrogen-oxygen mixture in this reactor) for catalytic recombination, ensuring that the hydrogen concentration in the upper gas chamber of the reactor core remains below 2.5%.

[0003] The main function of the gas recombination system is to catalytically recombine the hydrogen and oxygen gases produced by the reactor's radiation decomposition into water in a timely manner, ensuring that the hydrogen concentration does not exceed the limit and enabling the reactor to operate safely and stably.

[0004] While current gas recombination systems can catalytically recombine hydrogen and oxygen gases produced by reactor radiation decomposition into water in a timely manner, ensuring that the hydrogen concentration does not exceed the limit and enabling the reactor to operate safely and stably, their gas recombination systems have a low degree of integration, a relatively complex system structure, and are difficult to inspect and maintain.

[0005] Therefore, there is an urgent need for a passive hydrogen-oxygen recombination device for uranyl nitrate solution reactors. This device should not only be able to catalytically recombine the hydrogen and oxygen gases produced by reactor radiation decomposition into water in a timely manner, ensuring that the hydrogen concentration does not exceed the limit and enabling the reactor to operate safely and stably, but also have a high degree of integration, a simple system structure, and be convenient for inspection and maintenance. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a passive hydrogen-oxygen recombination device for uranyl nitrate solution reactor that can ensure safe and stable operation of the reactor, has a high degree of integration, a simple system structure, and is convenient for inspection and maintenance.

[0007] To address the aforementioned technical problems, this invention provides a passive hydrogen-oxygen recombination device for a uranyl nitrate solution reactor, comprising: A device housing that is closed at one end; A gas inlet is provided at the open end of the device housing, and the connection between the gas inlet and the open end of the device housing is sealed. An inlet heater connected to a gas inlet is provided inside the housing of the device, and the other end of the inlet heater is sequentially connected to a pre-honeycomb catalyst and a post-honeycomb catalyst; A certain space is reserved between the sidewalls of the inlet heater, the pre-honeycomb catalyst, and the post-honeycomb catalyst and the inner wall of the device housing as a gas passage; The rear honeycomb catalyst is provided with a guide plate on the tail side wall, which maintains a certain distance from the inner wall of the device housing; A gas outlet communicating with the space is provided on one side of the end of the device housing.

[0008] Furthermore, a flange structure is provided at the gas inlet end, and the gas inlet end is connected to the pyrolysis gas outlet flange of the reactor vessel through a pipeline; a flange structure is provided at the gas outlet end, and the gas outlet end is connected to the jet pump through a pipeline flange, and the jet pump is connected to the reactor vessel through a pipeline. Furthermore, the gas inlet is sealed and fixedly connected to the opening end of the device housing by welding. Furthermore, a first pressure gauge is installed on the pipe connecting the gas inlet end to the pyrolysis gas outlet of the reactor vessel, and a second pressure gauge is installed on the pipe connecting the gas outlet end to the jet pump.

[0009] Furthermore, both the pre-cell honeycomb catalyst and the post-cell honeycomb catalyst are provided with a hexagonal channel structure made of porous ceramic material arranged in combination. Furthermore, thermometers are respectively installed at the inlet end of the pre-honeycomb catalyst, between the pre-honeycomb catalyst and the post-honeycomb catalyst, and at the outlet end of the post-honeycomb catalyst. Furthermore, the guide plate is fixedly installed on the rear side wall of the rear honeycomb catalyst by welding.

[0010] Furthermore, the cracked gas generated in the reactor vessel is heated to 100-150°C at the inlet heater through the gas inlet. The heated cracked gas is then catalyzed at the pre-honeycomb catalyst and the post-honeycomb catalyst to raise the hydrogen-oxygen recombination temperature to 250-350°C to generate water molecules and obtain a hydrogen-oxygen recombination mixture.

[0011] Furthermore, the hydrogen-oxygen composite gas is discharged from the outlet end of the post-honeycomb catalyst and then pumped from the gas outlet to the reactor vessel by a jet pump through a guide plate, forming a closed gas loop.

[0012] Furthermore, the heater does not need to be operated when the uranyl nitrate solution reactor is operating at full power. When the uranyl nitrate solution reactor is operating at low power and the hydrogen concentration is low, the operation of the heater can still ensure that the passive hydrogen-oxygen recombination device has a good catalytic hydrogen removal effect.

[0013] The present invention provides a passive hydrogen-oxygen recombiner for a uranyl nitrate solution stack. The inlet heater, pre-honeycomb catalyst, and post-honeycomb catalyst are housed inside the device casing. This reduces the need for valves before and after the heater, pre-honeycomb catalyst, and post-honeycomb catalyst, and also reduces pipeline requirements. This lowers the requirements for component arrangement, resulting in a higher degree of integration and simplification of the hydrogen-oxygen recombiner structure. This simplified structure significantly reduces the volume of the hydrogen-oxygen recombiner and saves equipment space.

[0014] Furthermore, the passive hydrogen-oxygen recombination device for uranyl nitrate solution stack provided by the present invention has an integral ceramic honeycomb structure for its pre-honeycomb catalyst and post-honeycomb catalyst, which can effectively improve the catalytic area and catalytic efficiency, greatly improve the hydrogen-oxygen recombination efficiency of uranyl nitrate solution stack, reduce processing costs, and improve economic benefits.

[0015] Meanwhile, the present invention provides a passive hydrogen-oxygen recombination device for a uranyl nitrate solution reactor, wherein both the gas inlet end and the gas outlet end are flange structures. The gas inlet end is connected to the pyrolysis gas outlet flange of the reactor vessel through a pipeline, and the gas outlet end is connected to the jet pump through a pipeline flange. The jet pump is connected to the reactor vessel through a pipeline. This not only enables the reactor to form a closed loop gas circuit, but also reduces the difficulty of arranging the hydrogen-oxygen recombination device and facilitates the inspection and maintenance of the equipment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a passive hydrogen-oxygen recombination device for a uranyl nitrate solution pile, provided as an embodiment of the present invention. Detailed Implementation

[0017] See Figure 1 The present invention provides a passive hydrogen-oxygen recombination device for a uranyl nitrate solution stack, comprising a gas inlet 1, an inlet heater 2, a pre-honeycomb catalyst 3, a post-honeycomb catalyst 4, a device housing 5, a guide plate 6, and a gas outlet 7.

[0018] Among them, the device housing 5 is a structure with a closed rear end and an open front end (here, the open end of the device housing 5 is considered to be the front end, and the closed end is considered to be the rear end).

[0019] The device housing 5 has a gas inlet 1 at its open end, and the connection between the gas inlet 1 and the open end of the device housing 5 is sealed.

[0020] In one specific embodiment of the present invention, the connection between the gas inlet 1 and the opening end of the device housing 5 is sealed and fixed by welding.

[0021] An inlet heater 2 is provided inside the housing 5, which is connected to the rear end of the gas inlet 1. The rear end of the inlet heater 2 is sequentially connected to the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4.

[0022] Among them, a certain space is reserved between the side walls of the inlet heater 2, the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4 and the inner wall of the device housing 5 as a gas passage.

[0023] A gas outlet 7 is provided on one side of the end of the device housing 5, which communicates with the space between the side wall of the inlet heater 2, the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4 and the inner wall of the device housing 5.

[0024] Furthermore, a guide plate 6 is provided on the rear side wall of the rear honeycomb catalyst 4, maintaining a certain distance from the inner wall of the device housing 5.

[0025] In one specific embodiment of the present invention, the guide plate 6 is fixedly installed on the tail side wall of the rear honeycomb catalyst 4 by welding.

[0026] The guide plate 6 can serve as the boundary between the inside and outside of the gas flow channel. The cracked gas enters the hydrogen-oxygen recombiner from the gas inlet 1, passes through the inlet heater 2, the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4, and then passes through the space between the side walls of the inlet heater 2, the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4 and the inner wall of the device housing 5, and is discharged from the hydrogen-oxygen recombiner from the gas outlet 7.

[0027] The gas inlet 1 is equipped with a flange structure at one end, and the gas inlet 1 is connected to the pyrolysis gas outlet flange of the reactor vessel through a pipeline. Furthermore, a flange structure is also provided at the end of the gas outlet 7, and the end of the gas outlet 7 is connected to the jet pump (not shown in the figure) through a pipe flange. The jet pump is connected to the reactor vessel through a pipe. The present invention provides a passive hydrogen-oxygen recombination device for a uranyl nitrate solution reactor. Since both the gas inlet 1 and the gas outlet 7 are flange structures, the gas inlet 1 is connected to the pyrolysis gas outlet flange of the reactor vessel through a pipeline, and the gas outlet 7 is connected to the jet pump through a pipeline flange. The jet pump is connected to the reactor vessel through a pipeline. This not only enables the reactor to form a closed-loop gas circuit, but also reduces the difficulty of arranging the hydrogen-oxygen recombination device, facilitates disassembly and installation, and makes the equipment inspection and maintenance convenient.

[0028] A first pressure gauge (not shown in the figure) is installed on the pipe connecting the gas inlet 1 to the pyrolysis gas outlet of the reactor vessel, and a second pressure gauge (not shown in the figure) is installed on the pipe connecting the gas outlet 7 to the ejector pump. The pressure gauges allow for real-time monitoring of the gas pressure difference between the inlet and outlet of the hydrogen-oxygen recombiner. A constant pressure difference indicates stable operation of the hydrogen-oxygen recombiner, while an increase in pressure difference indicates some degree of catalyst blockage, requiring disassembly of the hydrogen-oxygen recombiner to adjust the catalysts in the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4.

[0029] Among them, the pre-cell honeycomb catalyst 3 and the post-cell honeycomb catalyst 4 both adopt an integral ceramic honeycomb structure. The integral ceramic honeycomb structure is a hexagonal channel structure made of porous ceramic material, which has the characteristics of high porosity and low density, excellent mechanical properties and chemical stability. It can effectively improve the catalytic area and catalytic efficiency, greatly improve the hydrogen-oxygen recombination efficiency of uranyl nitrate solution stack, reduce processing costs and improve economic benefits.

[0030] Furthermore, the passive hydrogen-oxygen recombination device for uranyl nitrate solution stack provided by the present invention adopts a two-stage design for the catalytic converter, namely, setting a pre-honeycomb catalyst 3 and a post-honeycomb catalyst 4. When the honeycomb catalyst in the pre-honeycomb catalyst 3 fails, the honeycomb catalyst in the post-honeycomb catalyst 4 can still achieve hydrogen removal, which can ensure the continuous hydrogen-oxygen catalytic recombination of the hydrogen-oxygen recombination device.

[0031] Meanwhile, thermometers 8 are installed at the inlet end of the pre-honeycomb catalyst 3, between the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4, and at the outlet end of the post-honeycomb catalyst 4, respectively, to measure the reaction temperature at the front of the pre-honeycomb catalyst 3, the rear of the post-honeycomb catalyst 4, and between the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4. Since the temperature at the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4 is directly related to the hydrogen-oxygen recombination reaction, monitoring the temperature of the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4 can ensure the smooth progress of the hydrogen-oxygen recombination reaction in the hydrogen-oxygen recombination reactor.

[0032] By monitoring the temperature at three points—the inlet of the pre-honeycomb catalyst 3, the area between the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4, and the outlet of the post-honeycomb catalyst 4—if the temperature between the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4 is lower than the temperature at the outlet of the post-honeycomb catalyst 4, the catalyst bed of the catalyst can be considered to have failed. This can remind the operator to replace the catalyst bed of the catalyst.

[0033] Since the gas inlet 1 is connected to the reactor vessel cracked gas outlet flange via a pipe, the heater 2 does not need to be put into operation under full power conditions. Under low power conditions, the cracked gas generated in the reactor vessel can be heated to 100-150°C at the inlet heater 2 through the gas inlet 1. The heated cracked gas is then catalyzed at the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4, where the hydrogen-oxygen recombination temperature is raised to 250-350°C to generate water molecules and obtain a hydrogen-oxygen recombination mixture.

[0034] Furthermore, the gas outlet 7 is connected to the injection pump via a pipe flange. The injection pump is connected to the reactor vessel via a pipe. After the hydrogen-oxygen composite gas is discharged from the outlet of the post-honeycomb catalyst 4, it is guided by the guide plate 6 and then flows through the space between the inlet heater 2, the pre-honeycomb catalyst 3, and the side wall of the post-honeycomb catalyst 4 and the inner wall of the device shell 5. It is then pumped from the gas outlet 7 to the reactor vessel, forming a closed-loop gas circuit. This ensures that the hydrogen and oxygen produced by the cracking of the fuel solution in the reactor vessel can be catalytically combined into water vapor by the hydrogen-oxygen compositer and can be circulated. It also prevents radioactive gas from leaking into the plant environment and affecting environmental and personal safety.

[0035] Moreover, the passive hydrogen-oxygen recombination device for uranyl nitrate solution pile provided by the present invention uses materials that are resistant to high dose radiation and corrosion for all its components. It can operate continuously in an acidic environment for at least two years with 300 days of continuous operation per year, and can achieve a high hydrogen removal efficiency of ≥90% during its life cycle.

[0036] The present invention provides a passive hydrogen-oxygen recombiner for a uranyl nitrate solution stack. The inlet heater 2, the pre-honeycomb catalyst 3, and the post-honeycomb catalyst 4 are arranged inside the device housing 5. This reduces the need for valves before and after the inlet heater 2, the pre-honeycomb catalyst 3, and the post-honeycomb catalyst 4, and also reduces the number of pipelines. This lowers the requirements for component arrangement, resulting in a higher degree of integration of the hydrogen-oxygen recombining structure. The hydrogen-oxygen recombining structure is greatly simplified, making the hydrogen-oxygen recombining structure simple and significantly reducing the volume of the hydrogen-oxygen recombining device, thus saving equipment space.

[0037] When pyrolysis gas is generated in the uranyl nitrate solution reactor vessel, the pyrolysis gas can enter the inlet heater 2 through gas inlet 1. In the inlet heater 2, it is heated to 100-150°C. The heated pyrolysis gas then enters the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4 in sequence. At the pre-honeycomb catalyst 3 and the post-honeycomb catalyst 4, hydrogen and oxygen recombination is catalyzed, raising the gas temperature to 250-350°C. The hydrogen and oxygen gas in the pyrolysis gas rapidly undergo catalytic recombination to generate water molecules, resulting in a hydrogen-oxygen complex gas.

[0038] After the hydrogen-oxygen composite gas exits from the outlet of the post-honeycomb catalyst 4, it is guided by the baffle plate 6 as the boundary between the inner and outer parts. Then, it exits from the gas outlet 7 through the space between the inlet heater 2, the pre-honeycomb catalyst 3, the sidewall of the post-honeycomb catalyst 4, and the inner wall of the device casing 5. It is then pumped to the reactor vessel by a jet pump, forming a closed-loop gas circuit. This ensures that the hydrogen and oxygen produced by the cracking of the fuel solution in the reactor vessel can be catalytically recombine into water vapor by the hydrogen-oxygen recombination device, allowing for continuous circulation. Furthermore, because the cracked gas constantly circulates within the reactor vessel and the hydrogen-oxygen recombination device, it prevents radioactive gas leakage into the plant environment, thus avoiding environmental and personal safety risks.

[0039] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A non-energetic hydrogen-oxygen recombiner for a uranyl nitrate solution reactor, characterized in that, The device housing (5) is closed at one end; The open end of the device housing (5) is provided with a gas inlet (1), and the connection between the gas inlet (1) and the open end of the device housing (5) is sealed; The device housing (5) is provided with an inlet heater (2) in communication with the gas inlet (1), and the other end of the inlet heater (2) is sequentially connected with a front honeycomb catalyst (3) and a rear honeycomb catalyst (4); The space between the side walls of the inlet heater (2), the front honeycomb catalyst (3) and the rear honeycomb catalyst (4) and the inner wall of the device housing (5) is reserved as a gas passage; The tail side wall of the rear honeycomb catalyst (4) is provided with a guide plate (6) reserved at a certain distance from the inner wall of the device housing (5); The end of the device housing (5) is provided with a gas outlet (7) in communication with the space. The end of the gas inlet (1) is provided with a flange structure, and the end of the gas inlet (1) is communicated with the outlet flange of the reactor vessel through a pipeline; the end of the gas outlet (7) is provided with a flange structure, and the end of the gas outlet (7) is communicated with the jet pump through a pipeline flange, and the jet pump is communicated with the reactor vessel through a pipeline.

2. The uranium nitrate solution pile non-power operated hydrogen-oxygen recombiner according to claim 1, characterized in that, The connection between the gas inlet (1) and the open end of the device housing (5) is sealed and fixedly connected by welding.

3. The uranium nitrate solution pile non-power operated hydrogen-oxygen recombiner according to claim 2, characterized in that, A first pressure gauge is arranged on the pipeline connecting the end of the gas inlet (1) with the outlet of the reactor vessel, and a second pressure gauge is arranged on the pipeline connecting the end of the gas outlet (7) with the jet pump.

4. The uranium nitrate solution pile non-power operated hydrogen-oxygen recombiner according to claim 2, characterized in that, The front honeycomb catalyst (3) and the rear honeycomb catalyst (4) are both provided with a combined arrangement of hexagonal channel structures made of porous ceramic material.

5. The uranium nitrate solution pile non-power operated hydrogen-oxygen recombiner according to claim 1, characterized in that, Thermometers are arranged at the inlet end of the front honeycomb catalyst (3), between the front honeycomb catalyst (3) and the rear honeycomb catalyst (4), and at the outlet end of the rear honeycomb catalyst (4).

6. The uranium nitrate solution heap non-power operated hydrogen-oxygen recombiner according to claim 5, characterized in that, The guide plate (6) is fixedly arranged on the tail side wall of the rear honeycomb catalyst (4) by welding.

7. The uranium nitrate solution heap non-power operated hydrogen-oxygen recombiner according to claim 6, characterized in that, The pyrolysis gas generated in the reactor vessel is heated to 100-150℃ at the inlet heater (2) through the gas inlet (1), and the heated pyrolysis gas is catalyzed to generate water molecules at the front honeycomb catalyst (3) and the rear honeycomb catalyst (4) to obtain hydrogen-oxygen complex mixed gas.

8. The uranium nitrate solution heap non-power operated hydrogen-oxygen recombiner according to claim 7, characterized in that, The hydrogen-oxygen complex mixed gas is discharged from the outlet end of the rear honeycomb catalyst (4), passes through the guide plate (6), and is sent to the reactor vessel by the jet pump through the gas outlet (7), forming a closed loop of the hydrogen-oxygen complex.

9. The uranium nitrate solution pile non-power operated hydrogen-oxygen recombiner according to claim 8, characterized in that, The heater (2) does not need to be put into operation under the full power condition of the uranium nitrate solution reactor, and when the uranium nitrate solution reactor is in low power condition and the hydrogen concentration is low, the heater (2) can still ensure that the passive hydrogen-oxygen complex has good catalytic hydrogen removal effect.

10. The uranium nitrate solution pile non-power operated hydrogen-oxygen recombiner according to claim 6, characterized in that, ​

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