Oxygen control and measurement modular device for liquid lead-bismuth alloy

Abstract

The invention belongs to a modularized device for controlling and measuring oxygen, and particularly relates to a modularized device for controlling and measuring oxygen for liquid lead-bismuth alloy. An oxygen controlling and measuring modular device for liquid lead bismuth alloy comprises a deionized water tank, the deionized water tank is connected with a constant-temperature water bath through a peristaltic pump, and external high-purity argon, mixed gas of argon and 5% hydrogen and mixed gas of argon and 5% oxygen are connected with the constant-temperature water bath through a gas mixer. The circulating cooler is connected with the constant-temperature water bath device and ensures that the temperature of the constant-temperature water bath device is kept constant, the gas oxygen analyzer is connected with the constant-temperature water bath device through the dew-point instrument and samples a mixture in the constant-temperature water bath device, and the constant-temperature water bath device is further connected with an external tail gas purification device. The device has the remarkable effects that the device is simple in structure, low in manufacturing cost and convenient to manufacture, install and overhaul, and adopted materials and products are mature products.

Description

Technical Field

[0001] The invention belongs to a modular device for controlling and measuring oxygen, and in particular relates to a modular device for controlling and measuring oxygen for liquid lead-bismuth alloy. Background Art

[0002] Lead-bismuth alloy has become the preferred material for reactor coolant due to its special thermophysical and chemical properties, and has been widely studied in the fourth-generation nuclear reactor technology. An important problem with the use of lead-bismuth as coolant in reactors is the corrosion of structural materials in the loop. Since the main alloying component of reactor structural material steel is iron, iron has a high solubility in high-temperature liquid lead-bismuth alloy. If no protective measures are implemented, liquid lead-bismuth will corrode steel severely through mass dissolution. Structural material corrosion is a major challenge for lead-bismuth as a nuclear coolant for reactors and advanced nuclear reactors.

[0003] One way to reduce corrosion is to form a stable oxide layer on the surface of the structural material to protect the structural material matrix, because the solubility of metal oxides is much lower than the solubility of the alloying elements of the steel matrix. The formation of a stable oxide layer on the surface of the structural material requires sufficient dissolved oxygen in the liquid lead and bismuth, but the oxygen concentration must also be lower than the limit for PbO formation. PbO formed by excessive oxygen may block or destroy the system, and also provides an oxygen source that is difficult to remove. For this reason, it is very necessary to control the oxygen concentration in the lead-bismuth alloy. By controlling the concentration of dissolved oxygen in lead and bismuth, an effective oxide layer is obtained on the surface of the structural material steel matrix to enhance the corrosion resistance of the structural material.

[0004] There are two main oxygen control methods commonly used in various loop systems in China: gas-phase oxygen control and solid-phase oxygen control. Liquid lead-bismuth alloy loop oxygen control systems also mainly use these two methods, but there is no finalized product for the oxygen control system and it is still in the research and development stage. The principle of solid-phase oxygen control is based on the different concentrations of dissolved oxygen in the lead-bismuth alloy at different temperatures to achieve the purpose of oxygen control. When the temperature drops, the oxygen in the liquid lead-bismuth alloy will precipitate in the form of lead oxide grains near or on the surface of the lead oxide pellets. When the temperature rises, it will accelerate the dissolution of the lead oxide particles in the liquid lead-bismuth alloy. The principle of gas-phase oxygen control is to control the content of hydrogen or oxygen (volume fraction) in the mixed gas introduced into the liquid lead-bismuth alloy, the mass flow rate of the mixed gas, and other methods, and to control the reaction rate of hydrogen and free oxygen (when the oxygen content in the lead-bismuth loop is high) or the reaction rate of oxygen and lead (when the oxygen content in the lead-bismuth loop is low), thereby controlling the oxygen concentration in the liquid lead-bismuth alloy.

[0005] Solid-phase oxygen control has very limited ability to reduce dissolved oxygen in the system and consumes a lot of energy. The control accuracy of oxygen content in liquid lead-bismuth alloy is generally required to reach 10 -6Therefore, it is difficult to achieve precise measurement and control of solid-phase oxygen control in the field of liquid lead-bismuth alloys, and it is generally not used. There are many types of gas-phase oxygen control mixed gases. Ar+H2, He+H2, H2O+H2, Ar+H2O+H2, etc. are commonly used for deoxygenation, and Ar+O2, He+O2, H2O+O2, Ar+H2O+O2, etc. are commonly used for oxygenation. In the domestic oxygen control product market, there are only products with separate functional technologies for deoxygenation or oxygenation, and there are no control products that integrate deoxygenation and oxygenation. In addition, due to the potential carburizing effect of CO / CO2 on structural materials, this gas system is not used for practicality and safety considerations. Summary of the invention

[0006] In view of the defects of the prior art, the present invention provides a modular oxygen control and measurement device for liquid lead-bismuth alloy.

[0007] The present invention is implemented as follows: a modular oxygen control and measurement device for liquid lead-bismuth alloy, which includes a deionized water tank, the deionized water tank is connected to a constant temperature water bath through a peristaltic pump, external high-purity argon, argon + 5% hydrogen mixed gas and argon + 5% oxygen mixed gas are connected to the constant temperature water bath through a gas mixer, a circulating cooler is connected to the constant temperature water bath and ensures that the temperature of the constant temperature water bath remains constant, a gas oxygen analyzer is connected to the constant temperature water bath through a dew point meter, and samples the mixture in the constant temperature water bath, and the constant temperature water bath is also connected to an external exhaust gas purification device.

[0008] As described above, a modular oxygen control and measurement device for liquid lead-bismuth alloy, wherein the above-mentioned argon + 5% hydrogen mixed gas and argon + 5% oxygen mixed gas are both mixed gases with volume fractions.

[0009] The modular oxygen control and measurement device for liquid lead-bismuth alloy as described above also includes a module outer frame, which is a three-dimensional bracket, and all equipment is arranged on the module outer frame.

[0010] The modular oxygen control and measurement device for liquid lead-bismuth alloy as described above also includes a control box, which is connected to all electronic equipment and controls their operation.

[0011] As described above, a modular oxygen control and measurement device for liquid lead-bismuth alloy is provided with self-locking casters at the bottom end of the outer frame of the module.

[0012] The remarkable effects of the present invention are: the device has a simple structure, low cost, is easy to manufacture, install and maintain, and the materials and products used are all mature products. It can be used in a liquid lead-bismuth alloy medium environment to control and measure oxygen. This device can not only be widely promoted and applied to lead-based reactor research and development projects of various domestic research institutions, but also, with the development of lead-based reactor experimental reactors, demonstration reactors and commercial reactors, this modular device can be used as a mature product to realize the supply of oxygen content control and measurement products for lead-bismuth reactors and related technical services.

[0013] Modular design of the device: This device integrates oxygen control pipelines and electrical instrumentation control systems. The outer packaging cabinet has a size of 1.0m×0.8m×1.8m. It has a reasonable structure, small footprint, easy operation and maintenance, and can be moved as a whole.

[0014] Flexible device control: This device adopts PLC system automatic control. After connecting to the central control system, the operator only needs to monitor the operating parameters on the computer (host computer) in the central control room. Whether the oxygen content in the lead-bismuth system is too high or too low, the gas phase oxygen control device can automatically adjust the oxygen content in the lead-bismuth system to within the set range. When the operating parameters are abnormal, an alarm will be issued, and personnel will be required to perform corresponding operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 : Schematic diagram of oxygen control device system;

[0016] Figure 2a : Assembly drawing of oxygen control device module;

[0017] Figure 2b :yes Figure 2a Back view of ;

[0018] Figure 3a : Module layout of oxygen control device (+0.00~EL+1.11m);

[0019] Figure 3b :Layout of oxygen control device module (+1.11~EL+1.88m)

[0020] Figure 4a : Front view of the outer frame of the oxygen control device module;

[0021] Figure 4b : Side view of the outer frame of the oxygen control device module;

[0022] Figure 4c : Axonometric drawing of the outer frame of the oxygen control device module;

[0023] Figure 4d :yes Figure 4a AA section view.

[0024] In the figure: 1. Deionized water tank, 2. Peristaltic pump, 3. Constant temperature water bath, 4. Circulating cooler, 5. Gas mixer, 6. Dew point meter, 7. Gas oxygen analyzer, 8. Control box, 9. Control panel, 10. Mass flow controller, 11. Self-locking casters, 12. Module outer frame, 13. To exhaust gas purification tank, 14. To purge system, 15. Gas cylinder hose connector DETAILED DESCRIPTION

[0025] The oxygen control device is composed of a gas circuit system, a water bath system, an instrument system, etc. The oxygen content in the circuit is obtained through an oxygen sensor, and deoxygenation or oxygen supplementation is automatically performed by comparing the actual oxygen content with the set oxygen content. The oxygen control device system diagram is shown in the figure Figure 1 shown.

[0026] The oxygen control process includes three kinds of gases: high-purity argon, argon + 5% hydrogen (volume fraction) mixed gas and argon + 5% oxygen (volume fraction) mixed gas, which are respectively installed in corresponding gas cylinders (configured on site as needed). Each gas pipeline is equipped with filters, gas quality controllers, regulating valves, one-way valves, etc. According to needs, argon + hydrogen mixed gas with a hydrogen content of 0-5% (used when the oxygen content of the lead-bismuth circuit is high) and argon + oxygen mixed gas with an oxygen content of 0-5% (used when the oxygen content of the lead-bismuth circuit is low) can be output respectively. Argon can be mixed with hydrogen-containing argon and oxygen-containing argon in a mixer, and then, according to needs, it can be passed into a constant temperature water bath. In this way, water vapor is added to the mixed gas, and the water vapor content can be controlled by adjusting the temperature of the constant temperature water bath. The dew point meter can measure the water vapor content in the mixed gas, and finally the mixed gas is passed into the lead-bismuth system to control the oxygen content.

[0027] Since the pressure of the lead-bismuth circuit is not high, the working pressure of the gas-phase oxygen control device is also not high, generally <0.3MPaG, and the mixed gas used for oxygen control is at room temperature. Therefore, the design pressure of the gas-phase oxygen control device pipeline system is 0.6MPaG and the design temperature is 100℃.

[0028] The gas-phase oxygen control equipment is filled with gas pipelines with a diameter of DN10 (i.e. 3 / 8”). The modular equipment is connected to the lead-bismuth loop system through two gas-phase pipelines. One pipeline is used to fill the lead-bismuth loop with oxygen control mixed gas, and the reacted oxygen control mixed gas is led out by another pipeline. The gas-phase oxygen control device has two interfaces reserved, which are connected to the user's lead-bismuth system through hoses and ferrules. The needle valve uses anlok N3 series needle valve, order number N31-6-A, end type 3 / 8in.T tube ferrule connector, 304 material. The check valve uses anlok CV series check valve, order number SS-CV-6-A-1, and end type British ferrule pipe connector.

[0029] The instrumentation and control system is controlled by PLC, and remote signals such as dissolved oxygen content, water vapor content, gas flow, user's oxygen content sensor, temperature sensor, etc. are all connected to the PLC control cabinet. The gas phase oxygen control device can also transmit signals to the central control room through communication for centralized control.

[0030] A specific example is given below.

[0031] Device size (length × width × height): 1.0m × 0.8m × 1.8m. Under the condition of meeting the requirements of process, layout and maintenance space, various professional items such as equipment, valves and process pipelines are arranged as compactly as possible to form a relatively complete system boundary. The general assembly diagram of the oxygen control device module is shown in Figure 2, and the equipment layout is shown in Figure 3.

[0032] (1) Equipment layout

[0033] The main equipment of the device includes deionized water tank, peristaltic pump, constant temperature water bath, gas mixer, circulating cooler, dew point meter, gas oxygen analyzer and mass flow controller. Among them, the deionized water tank, peristaltic pump, constant temperature water bath and gas mixer are mainly arranged between 0.00m-1.12m (relative to the indoor ground elevation), close to the front half of the front of the device; the dew point meter, gas oxygen analyzer and mass flow controller are arranged between 1.12m-1.88m on the upper floor of the device, mainly to facilitate the arrangement of equipment instrument valve operation.

[0034] (2) Pipeline layout

[0035] The device pipelines are connected with stainless steel 3 / 8” ferrules. Various pipelines are arranged in rows and bundles, and common support is considered as much as possible.

[0036] (3) External frame design

[0037] The structural frame of the entire device is made of 4040LC aluminum profiles, connected by corner pieces, and covered with 2mm thick brushed stainless steel outer panels; self-locking casters are set at the bottom of the device to achieve flexible transportation and positioning of the device. The device operating valve handles and instrument touch and control screens are all arranged in order on the upper part of the operation panel, which is convenient and quick to operate. The detailed diagram of the module outer frame is shown in Figure 4.

Claims

1. A modular oxygen control and measurement device for liquid lead-bismuth alloy, characterized in that: The invention comprises a deionized water tank (1), wherein the deionized water tank (1) is connected to a constant temperature water bath (3) via a peristaltic pump (2), external high-purity argon, argon + 5% hydrogen mixed gas and argon + 5% oxygen mixed gas are connected to the constant temperature water bath (3) via a gas mixer (5), a circulating cooler (4) is connected to the constant temperature water bath (3) and ensures that the temperature of the constant temperature water bath (3) remains constant, a gas oxygen analyzer (7) is connected to the constant temperature water bath (3) via a dew point meter (6) and samples the mixture in the constant temperature water bath (3), and the constant temperature water bath (3) is also connected to an external tail gas purification device.

2. A modular oxygen control and measurement device for liquid lead-bismuth alloy according to claim 1, characterized in that: The above-mentioned argon + 5% hydrogen mixed gas and argon + 5% oxygen mixed gas are both mixed gases with a volume fraction.

3. A modular oxygen control and measurement device for liquid lead-bismuth alloy according to claim 2, characterized in that: It also comprises a module outer frame (12), which is a three-dimensional support, and all devices are arranged on the module outer frame (12).

4. A modular oxygen control and measurement device for liquid lead-bismuth alloy according to claim 3, characterized in that: It also comprises a control box (8), which is connected to all electronic devices and controls their operation.

5. A modular oxygen control and measurement device for liquid lead-bismuth alloy according to claim 4, characterized in that: A self-locking caster (11) is arranged at the bottom end of the module outer frame (12).

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