Operation Control Methods for Medical Isotope Production Reactors

Abstract

This application discloses a method for controlling the operation of a medical isotope production reactor. This method, based on a fuel solution with a specified uranium concentration, pH value, catalyst content, and catalyst content, preliminarily controls the generation of uranium hydrolysis precipitation, corrosion, and fission product precipitation by coupling reactions between uranyl ions and fission, radiolysis, and corrosion products. The method further integrates multiple factors, including reactor power density, solution replenishment rate, operating temperature range, and operating cycle, to design a control strategy for the medical isotope production reactor. This reduces the likelihood of complex chemical reactions occurring due to coupling between uranyl ions and fission, radiolysis, and corrosion products, effectively suppressing precipitation caused by multiple factors during the operation of the medical isotope production reactor. This eliminates the feedback effect of precipitation on core reactivity, ensures the stability of the medical isotope production reactor during operation, and facilitates the rapid extraction of required nuclides.

Description

Technical Field

[0001] The present application relates to the technical field of isotope production reactors, and in particular to an operation control method for a medical isotope production reactor. Background Art

[0002] Medical Isotope Production Reactors (MIPRs) are aqueous homogeneous reactors that typically use uranyl nitrate or uranyl sulfate solutions as fuel to produce medical isotopes.

[0003] The fission products, radiolysis products and corrosion products produced during MIPR operation will cause the liquid fuel to react with some of the fission products, thereby changing the form of uranium in the solution. At the same time, the fission products may also react with each other and precipitate out in the form of precipitation. The increase in the radioactivity of the fission products and the solution will also lead to the generation of H2O and NO. 3- The components undergo irradiation decomposition reactions, forming various radiolysis products such as H₂, O₂, N₂, nitrogen oxides, H₂O₂, and ·OH. The formation of these radiolysis products can lead to the formation of bubbles and change the pH of the fuel solution and the uranium species in the solution. Furthermore, highly oxidizing radiolysis products such as ·OH can accelerate the corrosion of the reactor vessel.

[0004] Related technologies utilize the hydrolysis behavior of uranyl ions to prevent uranium peroxide precipitation by controlling uranyl ion concentration, solution pH, solution temperature, or metal ion-catalyzed decomposition of hydrogen peroxide. However, during MIPR service, the lack of precipitation in liquid fuel is influenced by multiple factors, including uranyl nitrate concentration, fission products, radiolysis products, corrosion products, solution pH, and operating temperature. However, current research results mostly focus on isolated studies of the hydrolysis behavior of uranyl ions or the precipitation reaction between uranyl ions and specific radiolysis products, without fully considering the coupled precipitation effects of these factors. This results in insufficient MIPR stability in practical applications. Summary of the Invention

[0005] In view of this, the present application provides an operation control method for a medical isotope production reactor, which can effectively suppress precipitation caused by multiple factors during the operation of the isotope production reactor.

[0006] According to one aspect of the present application, a method for controlling the operation of a medical isotope production reactor is provided, comprising:

[0007] The operation of a medical isotope production reactor is controlled according to target operating parameters to suppress the formation of precipitates in a fuel solution of the medical isotope production reactor, wherein the fuel solution is formulated according to the target fuel parameters, and the target operating parameters include at least one of a reactor power density, a solution replenishment rate, an operating temperature range, and an operating cycle.

[0008] Optionally, the target operating parameter includes an operating cycle, and controlling the operation of the medical isotope production reactor according to the target operating parameter includes:

[0009] Determining a first preset duration and a second preset duration in a current operating cycle based on a difference between a content of a target metal ion related to a corrosion reaction in the fuel solution in a previous operating cycle and a content threshold of the target metal ion, wherein the target metal ion includes a chromium ion and / or a ruthenium ion, the chromium ion content threshold is 0.04 g / L to 0.06 g / L, and the ruthenium ion content threshold is 0.015 g / L to 0.03 g / L;

[0010] In response to the isotope production reactor operating for the first preset time, performing a nuclide extraction process on the fuel solution to reduce the chromium ion content to below the chromium ion content threshold;

[0011] In response to the isotope production reactor being in an operating state, accumulating operating hours;

[0012] If the working time is greater than or equal to the second preset time, controlling the purification device to purify the fuel solution so that the ruthenium ion content is lower than the ruthenium ion content threshold;

[0013] The purification rate of the metal impurity ions in the purification treatment is ≥70%.

[0014] Optionally, the target operating parameters include reactor power density, a preset start-up temperature, and an operating temperature range, and controlling the operation of the medical isotope production reactor according to the target operating parameters includes:

[0015] controlling the start-up of the medical isotope production reactor;

[0016] controlling the power of the medical isotope production reactor to increase in a stepwise manner according to at least one startup power corresponding to the power density until a preset stable power is reached;

[0017] In response to the medical isotope production reactor being in an operating state, a temperature control device of the medical isotope production reactor is controlled to heat or cool the fuel solution according to the operating temperature range corresponding to the startup power.

[0018] Optionally, the preset stable power is 200kW to 2000kW, the power density is less than 1.8kW / L, and the operating temperature range is 20°C to 90°C.

[0019] Optionally, the startup power and the lower limit of the operating temperature range are positively correlated.

[0020] Optionally, the target fuel parameter includes a solution replenishment rate, and controlling the operation of the medical isotope production reactor according to the target operating parameter includes:

[0021] detecting the pH value of the fuel solution according to a preset adjustment period;

[0022] If the pH value of the fuel solution exceeds a preset pH range, adding an acidic solution and water to the fuel solution according to different solution replenishment rates;

[0023] Wherein, the acidic solution includes nitric acid solution or sulfuric acid solution.

[0024] Optionally, the concentration of the acidic solution is 7 mol / L to 14 mol / L, and the replenishment rate of the acidic solution is 4×10 -3 L / (kW·h)~8.2×10 -3 L / (kW·h);

[0025] The water replenishment rate is less than or equal to 2.8×10 -3 L / (kW·h).

[0026] Optionally, the target fuel parameter includes at least one of a pH value, a uranium concentration, a catalyst, and a content of the catalyst in the fuel solution.

[0027] Optionally, the pH value of the fuel solution is in the range of 0 to 2.8;

[0028] The uranium concentration is less than or equal to 400 gU / L.

[0029] Optionally, the catalyst comprises nitrate, wherein the nitrate contains at least one of iron, manganese, nickel, copper and silver;

[0030] The content of the catalyst in the fuel solution is 0.5 g / L to 3.5 g / L.

[0031] The above-mentioned technical solution, by coupling the reactions between uranyl ions and fission, radiolysis, and corrosion products, initially controls the generation of uranium hydrolysis precipitation, corrosion, and fission product precipitation based on a fuel solution with a specified uranium concentration, pH value, catalyst, and its content. Furthermore, a control strategy for the isotope production reactor is designed by integrating multiple factors, including reactor power density, solution replenishment rate, operating temperature range, and operating cycle. This reduces the possibility of complex chemical reactions occurring due to coupling between uranyl ions and fission, radiolysis, and corrosion products, effectively suppressing precipitation caused by multiple factors during the operation of the isotope production reactor, eliminating the feedback effect of precipitation on core reactivity, ensuring the stability of the isotope production reactor during operation, and facilitating the rapid extraction of desired nuclides.

[0032] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0034] Figure 1 A schematic flow chart of an operation control method for an isotope production reactor provided in an embodiment of the present application is shown;

[0035] Figure 2 A schematic diagram showing the relationship between uranium species, pH value, and hydrogen peroxide concentration when the uranyl ion concentration is 0.63 mol / L provided in the examples of the present application;

[0036] Figure 3 A schematic diagram showing the relationship between uranium species, pH value, and hydrogen peroxide concentration when the uranyl ion concentration is 1.0 mol / L provided in the examples of the present application;

[0037] Figure 4 A schematic diagram showing the relationship between uranium species, pH value, and hydrogen peroxide concentration when the uranyl ion concentration is 1.2 mol / L provided in the examples of the present application;

[0038] Figure 5 A schematic diagram showing the relationship between uranium species, pH value, and hydrogen peroxide concentration when the uranyl ion concentration is 1.5 mol / L provided in the examples of the present application;

[0039] Figure 6A schematic diagram showing the relationship between uranium species, pH value, and hydrogen peroxide concentration when the uranyl ion concentration is 2.0 mol / L provided in the examples of the present application is provided. DETAILED DESCRIPTION

[0040] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

[0041] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and are not to be construed as limiting the present application.

[0042] It will be understood by those skilled in the art that, unless expressly stated otherwise, the singular forms "a", "an", "said" and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of this application refers to the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, or there may be intermediate elements. In addition, "connected" or "connected" as used herein may include wireless connection or wireless fusion. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0043] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in a variety of different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of this application thorough and complete and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art.

[0044] Isotope production reactors (IPRs) are nuclear reactors specifically designed for the production of radioactive isotopes. They are capable of mass-producing a variety of radioactive isotopes needed in medicine, industry, and scientific research. For example, a MPR produces radionuclides such as molybdenum-99, iodine-131, and strontium-89 through fission reactions using uranyl nitrate or sulfate solutions as the fuel. The uranium in the solution serves as both the "fuel" for the nuclear reaction and the "target" for producing the radioactive isotopes.

[0045] In this embodiment, an operation control method of an isotope production reactor is provided. Figure 1 As shown, the method includes:

[0046] Step 110: Control the operation of the isotope production reactor according to the target operating parameters to suppress the formation of precipitates in the fuel solution of the isotope production reactor.

[0047] The target operating parameters include at least one of reactor power density, solution replenishment rate, operating temperature range and operating cycle.

[0048] Furthermore, the fuel solution is prepared based on target fuel parameters. These target fuel parameters include at least one of pH, uranium concentration, catalyst, and the catalyst content in the fuel solution. Generally, the uranium concentration is less than or equal to 400 gU / L. Typically, the uranium concentration is controlled within the range of 200 gU / L to 300 gU / L. Within this range, the higher the uranium concentration, the better.

[0049] The operation control method for an isotope production reactor provided in an embodiment of the present application preliminarily controls the generation of uranium hydrolysis precipitation, corrosion, and fission product precipitation by coupling the reactions between uranyl ions and fission products, radiolysis products, and corrosion products, based on a fuel solution with a specified uranium concentration, pH value, catalyst, and its content. Furthermore, the control strategy for the isotope production reactor is designed by integrating multiple factors, including reactor power density, solution replenishment rate, operating temperature range, and operating cycle. This reduces the possibility of complex chemical reactions occurring due to coupling between uranyl ions and fission products, radiolysis products, and corrosion products, effectively suppressing precipitation caused by multiple factors during the operation of the isotope production reactor, eliminating the feedback effect of precipitation on core reactivity, ensuring the stability of the isotope production reactor during operation, and facilitating the rapid extraction of nuclides.

[0050] It should be noted that, depending on the type, conditions and mechanism of precipitate formation under reactor operating conditions, the following reactions may occur in the fuel solution.

[0051] (1) For the hydrolysis reaction of uranyl ions.

[0052] During the irradiation process in the reactor, the acid radical ions decompose under the action of fission products, neutrons and gamma rays, resulting in the loss of nitrate radicals, which will cause the pH to rise, that is, the acidity of the fuel solution to decrease. When the acidity of the fuel solution decreases, the uranyl ions (UO2 2+ ) is hydrolyzed to form UO2(OH) + , as the pH value increases, UO2(OH) + A reaction occurs to form UO3·H2O precipitate.

[0053] The decomposition reaction formula is as follows:

[0054]

[0055] The hydrolysis reaction formula is as follows:

[0056]

[0057] (2) For related reactions of irradiation decomposition, such as H2O and NO3 - The radiation decomposition of components and the reactions triggered by the radiation products.

[0058] Under the action of radiation particles, water molecules are excited and ionized, forming hydrogen free radicals ·H and hydroxyl free radicals ·OH. ·H and ·OH combine to form H2O, H2, and H2O2 (hydrogen peroxide). The H2O2 produced by water irradiation can react with UO2 2+ A chemical reaction occurs to form uranium ore (UO2(O2)·2H2O) precipitate.

[0059] The radiolysis reaction equation is as follows:

[0060] 3H2O→·H+·OH+H2+H2O2;

[0061] H2O2 and UO2(NO3)2 react to form UO2(O2)·2H2O. The relevant chemical reaction formulas are as follows:

[0062]

[0063] Taking into account the effects of thermal decomposition and catalysts, the formula for calculating the yield of hydrogen peroxide in the pile is as follows:

[0064] d(H2O2) / dt=λ×G×W×σ;

[0065] Where λ is a constant for unit conversion and can be set based on time accuracy, for example, λ = 0.0062; G is the number of hydrogen peroxide molecules produced per 100 eV absorbed; W is the reactor power density (in kW / L), which refers to the amount of energy released per unit volume. Higher reactor power density generates more heat and increases the overall reactor temperature; σ is the coupling reaction coefficient. For a homogeneous reactor in operation, approximately 96% of the hydrogen produced in the solution comes from fission recoil particles, 2% from neutrons, and 2% from gamma rays. The latter two terms are usually neglected. Since the recoil component is typically above 0.96, and some energy from prompt neutrons, gamma rays, and radioactive decay escapes from the solution, σ can be set to 0.96.

[0066] According to the amount of radiation decomposition, HNO3 is emitted by radiation decomposition, and water continues to return to the reactor through the gas recombination system with a recombination rate of not less than 95%.

[0067] (3) For corrosion and fission product related reactions, such as reactions between fission products and reactions between fission products and UO2 2+ reaction.

[0068] In the fuel solution, fission products refer to the various nuclides produced during the fission of uranium isotopes such as uranium-235 or uranium-233. Fission products consume acid radicals to form metal ions, such as Fe 3+ 、TcO4 - and MoO4 2- Under certain conditions, free metal ions react with other fission products and corrosion products to form metal salt precipitates with low solubility, such as molybdate precipitates. At the same time, some of the corroded Fe, Cr, and Ni will dissolve in the solution in the form of ions, among which Cr ions (Cr 3 + ) will accelerate the intergranular corrosion of 304L stainless steel. The corrosion rate of the container is related to the pH value of the solution. The lower the pH value, the faster the corrosion rate.

[0069] The reactions between coupled uranyl ions and fission products, corrosion products, and radiolysis products show that keeping the fuel solution at a low pH value during the configuration of the fuel solution and the operation of the isotope production reactor can increase the H + concentration, thereby effectively inhibiting uranium hydrolysis and precipitation. At the same time, in order to alleviate the corrosion of the container, the pH value should not be too low. Furthermore, the yield of hydrogen peroxide in the reactor is directly related to the reactor power density and the catalyst. Moreover, due to the instability of hydrogen peroxide, heating will cause it to decompose. The lower the reactor power density, the less hydrogen peroxide is produced. High temperature and catalysts can accelerate the decomposition of H2O2. By controlling the reactor power density, solution temperature and catalyst, the content of H2O2 in the solution can be reduced, thereby reducing the reaction between H2O2 and UO2(NO3)2 and UO4 saturation, thereby achieving control and elimination of precipitation. At the same time, it is stipulated that the reactor should be purified in time during actual operation to reduce the metal content in the solution, so as to avoid fission, precipitation of corrosion products and accelerated corrosion.

[0070] In one embodiment, when the uranium concentration is less than or equal to 400 gU / L, the pH value can be controlled within the range of 0 to 2.8 to take into account the effects of both corrosion products and radiolysis products on the fuel solution.

[0071] For example, using uranyl nitrate (UO2(NO3)2) as a fuel solution, uranyl nitrate is a salt of a strong acid and a weak base, and its solution is acidic. The pH of a mixed solution of uranyl nitrate and nitric acid is less than the pH corresponding to the nitric acid concentration. In an isotope reactor with a core capacity of 100L to 200L and a uranyl nitrate concentration of 230g / L, the pH of the uranyl nitrate can be lowered by adding additional nitric acid solution, thereby preventing hydrolysis and precipitation in the fuel solution.

[0072] In one embodiment, the target fuel parameters include a solution replenishment rate, and the operation of the isotope production reactor is controlled according to the target operating parameters, including: detecting the pH value of the fuel solution according to a preset adjustment period; if the pH value of the fuel solution exceeds the preset pH value range, adding an acidic solution and water to the fuel solution according to different solution replenishment rates.

[0073] Among them, the relationship between UO4, pH value and H2O2 obtained by thermodynamic calculation, as well as the relationship between uranium species and pH value and H2O2 concentration under different uranyl ion concentrations. Figures 2 to 6 As shown in the figure, when the pH is less than 2.8, if the solution system is to prevent uranium peroxide precipitation, the concentration of H2O2 needs to be controlled not to exceed the concentration limit of H2O2 at the corresponding pH value, so that uranium peroxide precipitation will not be produced in the solution. As the initial uranyl nitrate concentration increases, the change trend of the solution species in the reaction system is basically the same. Figure 4 、 Figure 5 、 Figure 6 Shown in UO2 2+ When the concentration exceeds 1.2 mol / L, some UO2 2+ The species area will become soluble [(UO2)2(OH)] 3+ , with UO2 2+ The increase in concentration, [(UO2)2(OH)] 3+ The speciation zone will gradually expand, while the precipitated speciation zone will increase only slightly. The formation of uranium species in the reaction system varies negligibly with uranium concentration. Therefore, during operation of an isotope production reactor, the uranyl ion concentration must not exceed solubility, the H₂O₂ concentration must be minimized, and the operating pH must be properly controlled to avoid UO₄ saturation and precipitation.

[0074] Specifically, the preset pH value range is 0 to 2.8. For example, the pH value may be 0.5, 1, 1.5, 1.76, 2.4, etc.

[0075] In this embodiment, the pH value of the fuel solution is periodically monitored. If the pH value does not meet the preset pH value range for preventing hydrolysis precipitation, an acidic solution and water are promptly added to the fuel solution to suppress the radiolysis reaction between water and acid, thereby ensuring that the reactor is in a state where precipitation does not occur.

[0076] Furthermore, taking into account the different decomposition amounts and reaction rates of radiolysis and hydrolysis reactions, acidic solution and water are added to the fuel solution at different non-replenishing rates to maintain a balance between acid and water, so that the uranium concentration in the fuel solution can ensure the normal operation of the reactor without precipitation.

[0077] It's understandable that acidic solutions of different concentrations require different replenishment rates. The higher the acidic solution concentration, the greater its ability to adjust pH. To maintain a balance between radiolysis and hydrolysis, the replenishment rate should be lower. When the solute in the fuel solution is uranyl nitrate, the acidic solution is nitric acid; when the solute in the fuel solution is uranyl sulfate, the acidic solution is sulfuric acid.

[0078] In one embodiment, the concentration of the acidic solution is 7 mol / L to 14 mol / L, and the replenishment rate of the acidic solution is 4×10 -3 L / (kW·h)~8.2×10 -3 L / (kW·h); water replenishment rate is less than or equal to 2.8×10 -3 L / (kW·h).

[0079] For example, to maintain the balance of HNO3 and water in the fuel solution, acid solution and water are added to the fuel solution according to different solution replenishment rates. For nitric acid with a concentration of 7.61 mol / L, the maximum acid replenishment rate is: the acid replenishment frequency shall not exceed 1 hour, and the acid replenishment amount shall be 8×10 -3 L / kW, which is a rate of 8×10 -3 L / (kW·h); the minimum acid replenishment rate is: the acid replenishment frequency shall not exceed 1h, and the acid replenishment amount shall be 7.76×10 -3 L / kW, which is a rate of 7.76×10 -3 L / (kW·h); for nitric acid with a concentration of 13.47 mol / L, the maximum acid replenishment rate is: the acid replenishment frequency shall not exceed 1 hour, and the acid replenishment amount is 4.49×10 -3 L / kW, which is a rate of 4.49×10 -3 L / (kW·h); the minimum acid replenishment rate is: the acid replenishment frequency shall not exceed 1h, and the acid replenishment amount shall be 4.4×10 -3 L / kW, which is a rate of 4×10 -3 L / (kW·h). At the same time, the water replenishment frequency should not be greater than 1 hour, and 2.32×10 -3 L / kW, the rate is 2.32×10 -3 L / (kW·h). It is understandable that the designed acid replenishment system has the ability to adjust acidity and the frequency of acid replenishment can be adjusted according to demand.

[0080] In one embodiment, when preparing the solution, an appropriate amount of catalyst is added to the fuel solution and mixed with the fuel solution. After the reactor is started, under the influence of temperature and catalyst, the catalyst interacts with the H2O2 produced by radiolysis, catalyzing the decomposition of the H2O2, thereby reducing the H2O2 content in the solution. This, in turn, reduces the reaction between H2O2 and UO2(NO3)2 and reduces UO4 saturation, thereby controlling and eliminating precipitation.

[0081] The decomposition reaction of H2O2 is as follows:

[0082] H2O2→0.5O2+H2O;

[0083] H2O2=(λ×G×W×σ) / (k+k cat (Cat));

[0084] Where k is the molar rate constant in the absence of catalyst; k cat is the catalytic constant; Cat is the catalyst concentration in mol / l.

[0085] Exemplarily, the catalyst includes a nitrate. When the solute in the fuel solution is uranyl nitrate, the catalyst for decomposing hydrogen peroxide is a nitrate catalyst, with the content in the fuel solution being greater than or equal to 0.5 g / L and less than or equal to 3.5 g / L. This promotes the thermal decomposition reaction of H2O2. This prevents precipitation even when the reactor is operating at 70°C and above 800 kW.

[0086] Furthermore, some cations of fission products and corrosion products such as Fe 3+ 、Ag + 、Ni 2+ 、Cu 2+ etc. can catalyze the thermal decomposition of H2O2. Copper and nickel salts are particularly effective in catalyzing the radiolysis of hydrogen gas into water and the decomposition of hydrogen peroxide into water. Therefore, a nitrate containing at least one of iron, manganese, nickel, copper, and silver can be selected as a catalyst. For example, the nitrate can be at least one of iron nitrate, manganese nitrate, nickel nitrate, silver nitrate, and copper nitrate.

[0087] In one embodiment, when the target operating parameters include reactor power density and operating temperature range, step 110, i.e., controlling the operation of the isotope production reactor according to the target operating parameters, includes: controlling the isotope production reactor to start up; controlling the power of the isotope production reactor to increase in a stepwise manner according to at least one startup power corresponding to the reactor power density until a preset stable power is reached; and in response to the isotope production reactor being in an operating state, controlling the temperature control device of the isotope production reactor to heat or cool the fuel solution according to the operating temperature range corresponding to the startup power.

[0088] The preset stable power is 200kW to 2000kW, for example, 500kW, 800kW, etc., which can be set according to the volume of the fuel solution. The operating temperature range is 20℃ to 90℃.

[0089] In this embodiment, the power of the isotope production reactor is increased in steps according to at least one startup power corresponding to the reactor power density until a preset stable power is reached, at which point the power increase is stopped and operation at the stable power is maintained. This gradually adjusts the isotope production reactor to conditions suitable for isotope production. This not only reduces thermal shock to the reactor's internal structure caused by rapid temperature changes, thereby extending the reactor's service life, but also allows for precise control of the power increase process through staged power increases, enabling better regulation of isotope production rates and ensuring optimal production capacity at each stage.

[0090] Furthermore, while the isotope production reactor is operating, the reactor's temperature control device adjusts the fuel solution temperature in real time based on the operating temperature range corresponding to the reactor's startup power. This maintains a stable temperature for the fuel solution, ensuring the reactor's safety and production efficiency. Furthermore, maintaining a certain temperature promotes the catalyst's decomposition of hydrogen peroxide, further reducing precipitation.

[0091] In one embodiment, step 110, controlling the operation of the isotope production reactor according to target operating parameters, includes controlling the power density of the isotope production reactor to be less than 1.8 kW / L, which may be 0.8 kW / L, 1.4 kW / L, 1.6 kW / L, etc.

[0092] In this embodiment, when the isotope production reactor operates at a power density below 1.8 kW / L, it generates relatively low heat, reducing the thermal effects of the radiolysis reaction and lowering the amount of hydrogen peroxide produced. Furthermore, the heat generated by the isotope production reactor heats the fuel solution. The higher temperature helps promote the catalyst's decomposition of hydrogen peroxide, resulting in higher catalytic efficiency and better precipitation control.

[0093] In practical applications, there's a positive correlation between the startup power and the lower limit of the operating temperature range. Therefore, at lower power levels, maintaining the required minimum temperature reduces coolant flow requirements, lowering both pump power requirements and system complexity. Furthermore, at higher power levels, operating at higher temperatures improves the thermal efficiency of the heat exchange system, enabling the reactor to produce more energy with lower fuel consumption. This allows the isotope production reactor to maintain stable operation at different power levels, reducing reactor instability caused by temperature fluctuations and improving overall system reliability.

[0094] For example, the catalyst Fe(NO3)3 content is 3 g / L, the core capacity is 120L-160L, the reactor power density is 1.58 kW / L, and the corresponding relationship between the startup power and the operating temperature range is shown in Table 1.

[0095] Table 1

[0096] Start-up power / kW 0 10 40 150 200 300 400 800 2000 Temperature lower limit / ℃ Freezing point 30 50 60 62 65 67 70 72 Temperature upper limit / ℃ 90 90 90 90 90 90 90 90 90

[0097] Among them, the freezing point of the fuel solution is about 0°C.

[0098] In one embodiment, the target operating parameters include an operating cycle, and the operating cycle includes: a first preset duration for triggering a nuclide extraction process during the operation of the isotope production stack, and a second preset duration for triggering a purification process; step 110, i.e., controlling the operation of the isotope production stack according to the target operating parameters, includes: determining a first preset duration and a second preset duration in the current operating cycle according to a difference between a content of target metal ions related to a corrosion reaction in the fuel solution in the previous operating cycle and a threshold value of a content of the target metal ions; performing a nuclide extraction process on the fuel solution in response to the first preset duration of the operation of the isotope production stack; accumulating the operating time in response to the isotope production stack being in an operating state; and controlling the purification device to perform a purification process on the fuel solution if the operating time is greater than or equal to the second preset time.

[0099] Among them, the target metal ions include chromium ions and / or ruthenium ions, the chromium ion content threshold is 0.04g / L~0.06g / L, and the ruthenium ion content threshold is 0.015g / L~0.03g / L. The purification treatment includes centrifugation, filtration, ion exchange, etc. The second preset time is used to trigger the purification treatment and can be reasonably set according to the isotope production reactor capacity, element concentration, etc. Exemplarily, the second preset time can be set to no more than half a year, such as 1 month, 3 months, half a year, etc., and the embodiments of this application will not be listed one by one.

[0100] In this embodiment, the isotope production reactor is shut down for a first preset operating time and performs nuclide extraction. Chromium ions in the solution are absorbed by the Al2O3 extraction column, reducing the chromium ion content of the fuel solution within the production reactor to below a corresponding threshold. Similarly, after the isotope production reactor reaches a second preset cumulative operating time, the control system activates the purification unit, which performs a primary purification of the fuel solution, filtering out unwanted impurities such as excess ruthenium ions and reducing the content of certain metals in the solution. This periodic cooling, sampling, and maintenance of the reactor prevents intergranular corrosion of the stainless steel container, reduces the impact of long-term operation on the equipment and isotope quality, and further minimizes the precipitation of fission and corrosion products, ensuring the safety and production efficiency of the isotope production reactor.

[0101] For example, it is known from experiments that Cr 3+In the presence of H2O2, Cr is generated. 6+ The fuel solution is extracted once every two days and all of it will be absorbed when it passes through the Al2O3 extraction column. 6+ Meet the requirement that the content is below 0.05g / L to avoid Cr 6+ The Ru ions generated by irradiation are controlled below 0.02 g / L through purification every six months.

[0102] It should be noted that the aforementioned multiple target operating parameters for controlling sedimentation can be used individually or in combination to achieve synergistic effects of different control strategies. Specific embodiment:

[0104] A 230gU / L uranyl nitrate fuel solution was used, and an additional 0.2mol / L nitric acid was added to reduce the pH value of the uranyl nitrate fuel solution to 1.76. During operation, the reactor power was 300kW when operating at full power, and the operating volume was between 120L and 160L. The reactor power density was 1.25kW / L to 1.67kW / L. During the startup process, different startup power steps were set. The reactor was first electrically heated until the temperature reached the lower limit of Table 1 before the power was increased. After stable operation, the power and density must be within the range allowed by Table 1. The reactor was operated for two days and shut down for one day for isotope extraction. During the operation of the reactor, acid was continuously replenished, and the frequency of acid replenishment should not exceed 1h. The concentration of nitric acid was 13.47mol / L, and the amount of acid replenishment was 4.4×10 -3 L / kW, and 2.32×10 -3 L / kW. Take samples every day to test the pH value of the fuel solution to ensure that the fuel solution is 0<pH<2.3, which can avoid the precipitation of UO3﹒2H2O. When the uranium concentration (uranyl ion concentration) is 230gU / L, if Figure 3 As shown, the concentration of hydrogen peroxide is controlled to be less than 10 - 6 mol / L. By adding 3 mg / L of Fe(NO₃)₃, the fuel solution is controlled to operate within the temperature and power ranges permitted in Table 1. Isotope extraction is performed using an Al₂O₃ extraction column, with two days of operation and one day of shutdown. Purification is performed every six months, with a purification rate of ≥70%. This ensures that the uranyl nitrate fuel solution does not precipitate.

[0105] Comparative Example:

[0106] A 230gU / L uranyl nitrate fuel solution was used, and an additional 0.2mol / L nitric acid was added to reduce the pH value of the uranyl nitrate fuel solution to 1.76. During operation, the reactor power was 300kW when operating at full power, and the operating volume was between 120L and 160L. The reactor power density was 1.25kW / L to 1.67kW / L. During the startup process, different startup power steps were set. The reactor was first electrically heated until the temperature reached the lower limit of Table 1 before the power was increased. After stable operation, the power and density must be within the range allowed by Table 1. The reactor was operated for two days and shut down for one day for isotope extraction. During the operation of the reactor, acid was continuously replenished, and the frequency of acid replenishment should not be greater than 1h. The concentration of nitric acid was 13.47mol / L, and the amount of acid replenishment was 2×10 -3 L / kW, and 2.32×10 - 3 The pH value of the fuel solution was tested daily and it was found that the pH value increased to more than 4 and precipitation occurred.

[0107] It should be noted that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0108] Those skilled in the art will understand that the accompanying drawings are only schematic diagrams of a preferred implementation scenario, and the modules or processes in the accompanying drawings are not necessarily required to implement the present application. Those skilled in the art will understand that the modules in the devices in the implementation scenario can be distributed in the devices of the implementation scenario according to the implementation scenario description, or can be changed accordingly and located in one or more devices different from the implementation scenario. The modules of the above-mentioned implementation scenario can be combined into one module, or can be further split into multiple sub-modules.

[0109] The serial numbers of the above application are for descriptive purposes only and do not represent the advantages or disadvantages of the implementation scenarios. The above disclosure only discloses several specific implementation scenarios of the present application, but the present application is not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the scope of protection of the present application.

Claims

1. A method for controlling the operation of a medical isotope production reactor, characterized in that: The method comprises: controlling the operation of a medical isotope production reactor according to target operating parameters to suppress the formation of precipitates in a fuel solution of the medical isotope production reactor, wherein the fuel solution is formulated according to the target fuel parameters, the target operating parameters including power density, solution replenishment rate, operating temperature range, and operating cycle; The controlling the operation of the medical isotope production reactor according to target operating parameters includes: controlling the start-up of the medical isotope production reactor; controlling the power of the medical isotope production reactor to increase in a stepwise manner according to at least one startup power corresponding to the power density until a preset stable power is reached; In response to the medical isotope production reactor being in an operating state, controlling a temperature control device of the medical isotope production reactor to heat or cool the fuel solution according to the operating temperature range corresponding to the startup power, the startup power corresponding to the power density; Determining a first preset duration and a second preset duration in a current operating cycle based on a difference between a content of a target metal ion related to a corrosion reaction in the fuel solution in a previous operating cycle and a content threshold of the target metal ion, wherein the target metal ion includes a chromium ion and / or a ruthenium ion, the chromium ion content threshold is 0.04 g / L to 0.06 g / L, and the ruthenium ion content threshold is 0.015 g / L to 0.03 g / L; In response to the isotope production reactor operating for the first preset time, performing a nuclide extraction process on the fuel solution to reduce the chromium ion content to below the chromium ion content threshold; In response to the isotope production reactor being in an operating state, accumulating operating hours; If the working time is greater than or equal to the second preset time, controlling the purification device to purify the fuel solution so that the ruthenium ion content is lower than the ruthenium ion content threshold; Among them, the purification rate of purified metal impurity ions is ≥70%.

2. The operation control method of the medical isotope production reactor according to claim 1, characterized in that: The preset stable power is 200kW~2000kW; The power density is less than 1.8kW / L The operating temperature range is 20°C to 90°C.

3. The operation control method of the medical isotope production reactor according to claim 1, characterized in that: The startup power and the lower limit of the operating temperature range are positively correlated.

4. The operation control method of a medical isotope production reactor according to claim 1, characterized in that: The target operating parameters include a solution replenishment rate, and controlling the operation of the medical isotope production reactor based on the target operating parameters includes: detecting the pH value of the fuel solution according to a preset adjustment period; If the pH value of the fuel solution exceeds a preset pH range, adding an acidic solution and water to the fuel solution according to different solution replenishment rates; Wherein, the acidic solution includes nitric acid solution or sulfuric acid solution.

5. The operation control method of the medical isotope production reactor according to claim 4, characterized in that: The concentration of the acid solution is 7mol / L~14mol / L, and the replenishment rate of the acid solution is 4×10 -3 L / (kW·h)~8.2×10 -3 L / (kW·h); The water replenishment rate is less than or equal to 2.8×10 -3 L / (kW·h).

6. The operation control method of a medical isotope production reactor according to claim 1, characterized in that: The target fuel parameter includes at least one of a pH value, a uranium concentration, a catalyst, and a content of the catalyst in the fuel solution.

7. The operation control method of a medical isotope production reactor according to claim 6, characterized in that: The pH value of the fuel solution is within the range of 0 to 2.8; The uranium concentration is less than or equal to 400 gU / L.

8. The operation control method of a medical isotope production reactor according to claim 6, characterized in that: The catalyst includes nitrate, wherein the nitrate contains at least one of iron, manganese, nickel, copper, and silver; The content of the catalyst in the fuel solution is 0.5 g / L to 3.5 g / L.

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