Method and device for measuring the content of dissolved iron in liquid lead bismuth

Abstract

The application is suitable for the field of nuclear power detection, and discloses a method and device for measuring the dissolved iron content in liquid lead bismuth, which comprises the following steps: S1, taking out the liquid lead bismuth and adding it into a test container, and heating the assembly to a set temperature; S2, injecting argon into the test container to remove other gases, and then inputting oxygen, and measuring the change of the dissolved oxygen concentration in the liquid lead bismuth through an oxygen detection sensor; S3, substituting the measured oxygen concentration change rate and the net oxygen addition rate into a differential equation to calculate the solubility product; and S4, deriving the dissolved iron content through the measured equilibrium oxygen concentration in the saturated iron and the solubility product obtained in step S3. The method for measuring the dissolved lead bismuth eutectic oxygen activity through the oxygen detection sensor is simple in operation, can quickly and accurately measure the dissolved iron content, and can keep the liquid metal system in a balanced state by adjusting the oxygen addition rate in the system, so that the experimental efficiency is higher.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear power detection, in particular to a method and device for measuring dissolved iron content in liquid lead bismuth. BACKGROUND

[0002] Lead bismuth eutectic (LBE) is selected as the coolant of the fourth generation nuclear reactor lead-cooled fast reactor. The main alloying elements of the primary circuit structure material are dissolved and corroded under the action of lead bismuth. The dissolved metal impurities react to form intermetallic compounds or oxides in LBE, which pollute the coolant and reduce its thermal performance, and even cause operation failure of pumps and valves, threatening the safety of the entire nuclear energy system. In order to study the content, form and transport properties of metal impurities in LBE, a monitoring method needs to be developed. The existing measurement methods are mainly based on chemical analysis or spectral analysis, which are complex to operate and have high requirements for samples. The existing test methods are mostly slow and inefficient. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a method and device for measuring dissolved iron content in liquid lead bismuth, aiming to solve the problem of slow and inefficient liquid detection in the prior art.

[0004] The present application adopts a method for measuring dissolved iron content in liquid lead bismuth, which comprises the following steps:

[0005] Step S1, take out the liquid lead bismuth and add it to the test container, and heat the assembly to a set temperature;

[0006] Step S2, inject argon into the test container to remove other gases, and then input oxygen, and measure the change of dissolved oxygen concentration in the liquid lead bismuth through an oxygen detection sensor;

[0007] Step S3, iron and dissolved oxygen interact to generate Fe3O4, and the chemical reaction equilibrium can be represented by the activity of dissolved iron and oxygen. The measured oxygen concentration change rate and net oxygen addition rate are substituted into the differential equation to calculate the solubility product;

[0008] Step S4, calculate the dissolved iron content by the measured equilibrium oxygen concentration in the saturated iron and the solubility product obtained in step S3.

[0009] In one embodiment, the solubility product K sp The calculation is as follows:

[0010] The solubility product K sp is expressed as:

[0011] where C Fe(LBE)C O(LBE) O

[0012] In an embodiment, the iron content dissolved in the liquid lead bismuth in step S4 can be calculated by the following formula:

[0013]

[0014] In an embodiment, the oxygen detection sensor is away from the heating assembly.

[0015] The present application solves the technical problem by providing a device for measuring the dissolved iron content in liquid lead bismuth, comprising a gas supply module, a test container, a detection module, and a heating assembly; the gas supply module is connected to the test container through a gas pipe, the test container is used to contain liquid lead bismuth, the detection module comprises an oxygen detection sensor, the oxygen detection sensor is inserted into the liquid lead bismuth, and the heating assembly is arranged on the outer wall of the test container and heats the test container.

[0016] In an embodiment, the gas supply module comprises an argon unit, an oxygen unit, and an argon-hydrogen mixed unit; the argon unit comprises an argon gas source, a first gas valve, and a first flow meter, which are connected in sequence through a gas pipe; the oxygen unit comprises an oxygen gas source, a second gas valve, and a second flow meter, which are connected in sequence through a gas pipe; the argon-hydrogen mixed unit comprises an argon-hydrogen mixed gas source, a third gas valve, and a third flow meter, which are connected in sequence through a gas pipe.

[0017] In an embodiment, the detection module is further provided with a first temperature sensor and a second temperature sensor, the first temperature sensor is arranged at the oxygen detection sensor, and the second temperature sensor is arranged in the liquid lead bismuth away from the oxygen detection sensor.

[0018] In an embodiment, the upper part of the test container is further provided with a retractable iron rod, and the extension direction of the retractable iron rod is towards the liquid lead bismuth.

[0019] The present application has the following beneficial effects: the method for measuring the dissolved lead bismuth eutectic (LBE) oxygen activity by the oxygen detection sensor is simple and convenient to operate, the dissolved iron content in the saturated state is quickly and accurately estimated, the liquid metal system is always in equilibrium state by adjusting the oxygen addition rate in the system, and the experimental efficiency is higher. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the present application, the present application will be further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings:

[0021] Figure 1 is a flow chart of a method for measuring the dissolved iron content in liquid lead bismuth in an embodiment of the present application;

[0022] Figure 2 is a whole structure diagram of a device for measuring the dissolved iron content in liquid lead bismuth in an embodiment of the present application;

[0023] Figure 3 is the solubility product of Fe-LBE-O of a device for measuring the dissolved iron content in liquid lead bismuth in an embodiment of the present application.

[0024] Reference Signs

[0025] 1, argon gas source; 2, oxygen gas source; 3, argon-hydrogen mixed gas source; 4, first gas valve; 5, second gas valve; 6, third gas valve; 7, first flowmeter; 8, second flowmeter; 9, third flowmeter; 10, gas inlet pipeline; 11, second temperature sensor; 12, oxygen detection sensor; 13, first temperature sensor; 14, telescopic iron rod; 15, exhaust pipeline; 16, flange cover; 17, test container; 18, heating assembly; 19, liquid lead bismuth. DETAILED DESCRIPTION

[0026] In order to have a more clear understanding of the technical features, objects and effects of the present application, the specific embodiments of the present application will be described in detail with reference to the drawings. In the following description, it should be understood that the orientation or positional relationship indicated by "front", "back", "up", "down", "left", "right", "vertical", "horizontal", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail" and the like is based on the orientation or positional relationship shown in the drawings, and is constructed and operated in a particular orientation, only for the convenience of describing the present technical solution, and should not be understood as indicating that the device or element must have a particular orientation, therefore it should not be regarded as limiting the present application.

[0027] It also needs to be explained that unless there is an explicit provision and limitation, the terms such as "installation", "connection", "connection", "fixation", "arrangement" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. When an element is referred to as "on" or "below" another element, the element can be "directly" or "indirectly" above the other element, or there can be one or more intervening elements. The terms "first", "second", "third" and the like are only for the convenience of describing the technical solutions, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features with "first", "second", "third" and the like can be explicitly or implicitly included one or more of the features. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0028] Figures 1 to 2 A method for measuring the dissolved iron content in liquid lead bismuth is shown in one embodiment of the present application. The method for measuring the dissolved iron content in liquid lead bismuth 19 can be used to measure the oxygen activity of the dissolved liquid lead bismuth (19). Based on the thermodynamic assumption, the dissolved iron content in the saturated state can be quickly and accurately estimated, which can include the following steps:

[0029] Step S1, take out the liquid lead bismuth 19 and add it to the test container 17. The heating assembly 18 raises the temperature to the set temperature.

[0030] Step S2, inject argon into the test container 17 to remove other gases, and then input oxygen. The change in dissolved oxygen concentration in the liquid lead bismuth 19 is measured by the oxygen detection sensor 12.

[0031] Step S3, iron and dissolved oxygen interact to form Fe3O4. The chemical reaction equilibrium can be represented by the activity of dissolved iron and oxygen. The measured oxygen concentration change rate and the net oxygen addition rate are substituted into the differential equation to calculate the solubility product.

[0032] Step S4, calculate the dissolved iron content by the measured equilibrium oxygen concentration in the saturated iron and the solubility product obtained in step S3.

[0033] The method for measuring the oxygen activity of the dissolved lead bismuth eutectic (LBE) by the oxygen detection sensor is simple to operate, and can quickly and accurately estimate the dissolved iron content in the saturated state. By adjusting the oxygen addition rate in the system, the liquid metal system is always in equilibrium, and the experimental efficiency is higher.

[0034] It is appreciated that the liquid lead bismuth 19 contains iron element, when argon is used to exclude air, the ratio of iron and oxygen in the liquid lead bismuth 19 will not change, when oxygen is introduced, the iron and oxygen will combine to produce magnetite when oxygen is dissolved into the liquid lead bismuth 19.

[0035] It is appreciated that the saturated iron refers to the saturated solubility of iron, the concentration of iron to be precipitated, the saturation range at 400°C is 10 -11 wt% to 10 -7 wt%.

[0036] In an embodiment, oxygen can be replaced by normal air to reduce the cost of testing.

[0037] In an embodiment, it can be included that the magnetite (Fe3O4) is generated by the interaction of iron and dissolved oxygen in the liquid lead bismuth (LBE), the magnetite (Fe3O4) is generated by the interaction of iron and dissolved oxygen in the liquid lead bismuth (LBE), the reaction is as follows:

[0038] Fe3O 4(s) f3Fe (LBE) +4[O] (LBE)

[0039] The activity of dissolved iron and oxygen in the liquid lead bismuth (LBE) can be expressed as:

[0040]

[0041] Where K is the equilibrium constant of the magnetite generation reaction, a Fe(LBE) is the activity of dissolved iron in the liquid lead bismuth 19, a O(LBE) is the activity of dissolved oxygen in the liquid lead bismuth 19;

[0042] The activity of iron in LBE is generally defined as the ratio of the concentration of iron to the solubility:

[0043]

[0044] And the activity of oxygen is expressed by the Sievert constant k o : a O(LBE) =k O ·C O(LBE) .

[0045] The solubility product is most commonly expressed as the concentration of the solute (usually in wt% units of liquid lead bismuth). This conversion implies a change in the standard state of the dissolved metal and oxygen atoms from the pure phase standard state to the Henry's law standard state. Thus, the solubility product K sp can be expressed as:

[0046] Reference Figure 3In one embodiment, the rate of change of the iron concentration in step S2 can be represented by a differential equation derived from the mass balance of oxygen and the solubility product in the system. First, the time derivative of the solubility product K sp of equation (1) is taken, since K sp is only a function of temperature, and thus the time derivative is zero:

[0047]

[0048] The relationship of the consumption of the chemical reaction is differentiated with respect to time t to obtain the solubility K sp :

[0049]

[0050] Equation (3) is substituted into equation (2) to obtain:

[0051]

[0052] where M o and M Fe are the molar masses of oxygen and iron, respectively, K sp is the solubility product of magnetite, r o (t) is the net oxygen addition rate as a function of time, and C o(LBE) is the measured oxygen concentration of the liquid lead bismuth 19.

[0053] It is understood that the mass balance of oxygen refers to the chemical reaction equilibrium, and the oxygen concentration is approximately between 10 -8 wt% and 10 - 4 wt%.

[0054] It is understood that the maximum rate of the net oxygen addition rate is 10 -9 wt% / s.

[0055] The dissolved iron content in step S4 can be calculated by the following equation:

[0056]

[0057] Figures 1 to 2 It is shown that the oxygen detection sensor 12 in one embodiment can include an oxygen detection sensor (12) that is remote from the heating assembly 18.

[0058] In one embodiment, step S2 can include, after inputting oxygen, inputting an argon and hydrogen mixture again, and the hydrogen can combine with the dissolved oxygen in the liquid lead bismuth 19 to become H2O molecules, which can have a tendency to reduce the dissolved oxygen concentration in the liquid lead bismuth 19.

[0059] It can be understood that hydrogen and oxygen in the liquid lead bismuth environment at 200-500℃ will have a micro oxidation-reduction reaction due to high temperature, generating H2O and heat, and further consuming the oxygen content in the liquid lead bismuth.

[0060] In an embodiment, the inputted argon and hydrogen ratio can be 19 parts of argon and 1 part of hydrogen. The low concentration of hydrogen can effectively reduce the reaction rate between hydrogen and oxygen, and the mixed argon can improve the ignition point of the mixed gas, avoiding the explosive reaction of hydrogen and oxygen.

[0061] Figure 2 A device for measuring the dissolved iron content in the liquid lead bismuth in an embodiment of the application is shown, which includes a gas supply module, a test container 17, a detection module and a heating assembly 18. The gas supply module is connected to the test container 17 through a gas pipe, the test container 17 is used to contain the liquid lead bismuth 19, the detection module includes an oxygen detection sensor 12, the oxygen detection sensor 12 is inserted into the liquid lead bismuth 19, and the heating assembly 18 is arranged on the outer wall of the test container 17 and heats the test container 17. The gas supply module supplies gas into the test container 17 through the gas pipe, and the oxygen detection sensor 12 detects the oxygen change rate in the liquid lead bismuth 19.

[0062] In an embodiment, a flange cover 16 is further arranged on the upper part of the test container 17, and the gas pipe and the detection module are arranged on the flange cover 16.

[0063] In an embodiment, the gas pipe includes an inlet gas pipe 10 and an outlet gas pipe, the gas supply module is connected to the inlet gas pipe 10, and the outlet gas pipe is connected from the inside of the test container 17 to the outside space.

[0064] In an embodiment, the argon unit includes an argon gas source 1, a first gas valve 4 and a first flow meter 7, which are sequentially connected through a gas pipe; the oxygen unit includes an oxygen gas source 2, a second gas valve 5 and a second flow meter 8, which are sequentially connected through a gas pipe; and the argon-hydrogen mixed unit includes an argon-hydrogen mixed gas source 3, a third gas valve 6 and a third flow meter 9, which are sequentially connected through a gas pipe. By using the flow meter and the gas valve to control the gas delivery, the delivery gas rate is ensured to be within the control range, which is conducive to controlling the reaction rate.

[0065] In an embodiment, the detection module can include a first temperature sensor 13 and a second temperature sensor 11, the first temperature sensor 13 is arranged at the oxygen detection sensor 12, and the second temperature sensor 11 is arranged in the liquid lead bismuth 19 away from the oxygen detection sensor 12. The first temperature sensor 13 is used to detect the temperature at the oxygen detection sensor 12, and the second temperature sensor 11 is used to detect the liquid lead bismuth 19.

[0066] In one embodiment, the upper portion of the test container 17 is further provided with a retractable iron rod 14, which extends towards the liquid lead bismuth 19. The retractable iron rod 14 is used to extend into the liquid lead bismuth 19 to increase the iron content in the liquid lead bismuth 19.

[0067] It can be understood that the above embodiments only express the preferred embodiments of the present application, which are described in a more specific and detailed manner, but cannot be understood as a limitation to the patent scope of the present application. It should be noted that the above technical features can be freely combined without departing from the concept of the present application, and several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, any equivalent transformation and modification within the scope of the claims of the present application shall belong to the scope of the claims of the present application.

Claims

1. A method of measuring the dissolved iron content in liquid lead bismuth, characterized by, The method comprises the following steps: Step S1, liquid lead bismuth (19) is taken out and added into a test container (17), and a heating assembly (18) is used to raise the temperature to a set temperature; Step S2, argon is first injected into the test container (17) to remove other gases, and then oxygen is injected, and the dissolved oxygen concentration in the liquid lead bismuth (19) is measured by an oxygen detection sensor (12); Step S3, iron and dissolved oxygen interact to generate Fe 3 O 4 The chemical reaction equilibrium is expressed by the activity of dissolved iron and oxygen. The measured oxygen concentration change rate and net oxygen addition rate are substituted into the differential equation to calculate the solubility product. Step S4, the dissolved iron content is calculated by the measured equilibrium oxygen concentration in the saturated iron and the solubility product obtained in step S3.

2. The method for measuring the content of dissolved iron in liquid lead bismuth according to claim 1, characterized in that, solubility product K sp The calculation is made by the following formula: solubility product K sp is represented as: wherein C Fe（LBE） content in liquid lead bismuth Fe content in liquid lead bismuth C O(LBE) content in liquid lead bismuth O content in liquid lead bismuth 3. The method for measuring the content of dissolved iron in liquid lead bismuth according to claim 2, characterized in that, The dissolved iron content in step S4 is calculated by the following formula: 。 4. The method for measuring the content of dissolved iron in liquid lead bismuth according to claim 1, characterized in that, The oxygen detection sensor (12) is away from the heating assembly (18).

5. The method for measuring the content of dissolved iron in liquid lead bismuth according to claim 1, characterized in that, In step S2, after the oxygen is injected, a mixture of argon and hydrogen is injected again.

6. The method for measuring the content of dissolved iron in liquid lead bismuth according to claim 4, characterized in that, The proportion of argon and hydrogen is 19 parts of argon and 1 part of hydrogen.

7. A device for measuring the dissolved iron content in liquid lead bismuth alloy, according to any one of claims 1 to 6, characterized in that, It comprises: The gas supply module, the test container (17), the detection module and the heating assembly (18); The gas supply module is connected to the test container (17) through a gas pipe, the test container (17) is used to contain liquid lead bismuth (19), the detection module comprises an oxygen detection sensor (12), the oxygen detection sensor (12) is inserted into the liquid lead bismuth (19), and the heating assembly (18) is arranged on the outer wall of the test container (17) and heats the test container (17); The upper part of the test container (17) is also provided with a telescopic iron rod (14), and the telescopic iron rod (14) extends towards the liquid lead bismuth (19).

8. The device for measuring the content of dissolved iron in liquid lead bismuth according to claim 7, characterized in that, The gas supply module comprises an argon unit, an oxygen unit and an argon-hydrogen mixed unit; The argon unit comprises an argon gas source (1), a first gas valve (4) and a first flow meter (7), and the argon gas source (1), the first gas valve (4) and the first flow meter (7) are connected in sequence through a gas pipe; The oxygen unit comprises an oxygen gas source (2), a second gas valve (5) and a second flow meter (8), and the oxygen gas source (2), the second gas valve (5) and the second flow meter (8) are connected in sequence through a gas pipe; The argon-hydrogen mixed unit comprises an argon-hydrogen mixed gas source (3), a third gas valve (6) and a third flow meter (9), and the argon-hydrogen mixed gas source (3), the third gas valve (6) and the third flow meter (9) are connected in sequence through a gas pipe.

9. The device for measuring the content of dissolved iron in liquid lead bismuth according to claim 7, characterized in that, The detection module is also provided with a first temperature sensor (13) and a second temperature sensor (11), the first temperature sensor (13) is arranged at the oxygen detection sensor (12), and the second temperature sensor (11) is arranged in the liquid lead bismuth (19) away from the oxygen detection sensor (12).

Images