Risk assistance map generation method and nuclear reactor applicable to same

Abstract

The invention provides a risk assistance graph generation method and an applicable nuclear reactor, the nuclear reactor comprises a containment vessel, the generation method comprises the following steps: calculating the air mole number in the containment vessel in an initial state; obtaining a first preset working condition curve to determine a hydrogen incombustible area; obtaining a second preset working condition curve to determine a hydrogen serious challenge zone and a hydrogen combustion zone; acquiring a third preset working condition curve to determine an unattended hydrogen region; and obtaining a fourth preset working condition curve to determine a future potential hydrogen combustion zone and a future potential hydrogen serious challenge zone. According to the generation method of the risk auxiliary graph and the nuclear reactor applicable to the method, the hydrogen risk of the containment under various working conditions can be evaluated, a nuclear power plant operator can be helped to evaluate the hydrogen risk according to the risk auxiliary graph and make a relieving decision, and the safety and reliability of the nuclear reactor are further guaranteed.

Description

Technical Field

[0001] The present application mainly relates to the field of nuclear power technology, and in particular to a method for generating a risk auxiliary map and a nuclear reactor to which the method is applicable. Background Art

[0002] In the event of a serious accident at a pressurized water reactor nuclear power plant, the overheated fuel cladding may react violently with the reactor's coolant water and water vapor to produce a large amount of hydrogen, which will be released into the containment through ruptures and valves. If the reactor pressure vessel fails and ruptures, the molten material inside will fall to the bottom of the compartment where the pressure vessel is located, interacting with the concrete of the bottom slab to produce additional hydrogen, as well as gases such as carbon monoxide and carbon dioxide. The mixing of hydrogen with water vapor and air in the containment may cause rapid combustion or even explosion of hydrogen, thus posing a challenge to the integrity of the containment. Summary of the invention

[0003] The technical problem to be solved by the present application is to provide a method for generating a risk auxiliary map and a nuclear reactor to which it is applicable, which can evaluate the hydrogen risk of the containment under various working conditions, and can help staff evaluate the hydrogen risk according to the risk auxiliary map and make mitigation decisions, thereby ensuring the safety and reliability of the nuclear reactor.

[0004] To solve the above technical problems, the present application provides a method for generating a risk auxiliary map, which is applicable to a nuclear reactor, wherein the nuclear reactor includes a containment shell, and the generation method includes the following steps: calculating the initial air molar number inside the containment shell in the initial state; obtaining a first preset operating condition curve to determine the hydrogen non-flammable area; obtaining a second preset operating condition curve to determine the hydrogen severe challenge area and the hydrogen combustion area; obtaining a third preset operating condition curve to determine the hydrogen area that does not need to be paid attention to; obtaining a fourth preset operating condition curve to determine the potential hydrogen combustion area and the potential hydrogen severe challenge area in the future.

[0005] Optionally, the generation method further comprises setting different zirconium water oxidation proportions to obtain a zirconium water reaction curve.

[0006] Optionally, calculating the initial number of moles of air inside the containment in the initial state includes: presetting an initial total pressure and an initial temperature of the containment; obtaining an initial steam partial pressure inside the containment through the initial temperature of the containment; calculating an initial air partial pressure inside the containment based on the initial total pressure of the containment and the initial steam partial pressure; and calculating the initial number of moles of air based on the initial air partial pressure.

[0007] Optionally, the method further comprises calculating the initial molar number of the air by the following formula:

[0008]

[0009] Wherein, V is the volume of the containment, P a0 is the air partial pressure, R is the ideal gas constant, T0 is the initial temperature, f vent is the exhaust share of the containment, and C is the conservative coefficient.

[0010] Optionally, obtaining a first preset operating condition curve to determine the hydrogen non-flammable area includes: presetting a first total pressure and a first initial temperature of the containment under the first preset operating condition, and calculating a first steam partial pressure based on the first initial temperature; calculating a first air partial pressure by using the initial air mole number; obtaining a first carbon monoxide mole number and a first carbon dioxide mole number, and calculating a first carbon monoxide partial pressure based on the first carbon monoxide mole number, and calculating a first carbon dioxide partial pressure based on the first carbon dioxide mole number; calculating a first hydrogen partial pressure based on the first total pressure, the first steam partial pressure, the first air partial pressure, the first carbon monoxide partial pressure, and the first carbon dioxide partial pressure; calculating a first hydrogen concentration by using the first hydrogen partial pressure; presetting different first total pressures and repeating the above steps to obtain the first preset operating condition curve.

[0011] Optionally, obtaining a first preset operating condition curve to determine the hydrogen non-flammable area also includes: calculating an updated steam partial pressure based on the first hydrogen concentration; obtaining an updated initial temperature based on the updated steam partial pressure; judging whether a first difference between the updated initial temperature and the first initial temperature is within a first error interval, and if the first difference is not within the first error interval, obtaining an updated hydrogen concentration based on the updated initial temperature, and calculating the updated steam partial pressure based on the updated hydrogen concentration, and repeating the above steps until the first difference is within the first error interval.

[0012] Optionally, obtaining a second preset operating condition curve to determine the hydrogen severe challenge zone and the hydrogen combustion zone includes: presetting the total pressure before combustion and the initial temperature before combustion of the containment under the second preset operating condition, and calculating the steam partial pressure before combustion based on the initial temperature before combustion; calculating the air partial pressure before combustion by the initial air mole number; obtaining the carbon monoxide mole number before combustion and the carbon dioxide mole number before combustion, and calculating the carbon monoxide partial pressure before combustion based on the carbon monoxide mole number before combustion, and calculating the carbon dioxide partial pressure before combustion based on the carbon dioxide mole number before combustion; calculating the hydrogen partial pressure before combustion based on the total pressure before combustion, the steam partial pressure before combustion, the air partial pressure before combustion, the carbon monoxide partial pressure before combustion, and the carbon dioxide partial pressure before combustion; calculating the hydrogen concentration before combustion by the hydrogen partial pressure before combustion; presetting a different second total pressure and repeating the above steps to obtain the second preset operating condition curve.

[0013] Optionally, obtaining a second preset operating condition curve to determine the hydrogen severe challenge zone and the hydrogen combustion zone also includes: calculating the total molar number of the containment before combustion based on the hydrogen partial pressure before combustion; calculating the total molar number of the containment after combustion, the total pressure of the containment after combustion, the temperature rise of the containment after combustion, and the failure pressure of the containment; calculating a second updated initial temperature based on the total molar number of the containment before combustion, the total molar number of the containment after combustion, the temperature rise, the failure pressure, and the total pressure of the containment after combustion; judging whether a second difference between the second updated initial temperature and the initial temperature before combustion is within a second error interval, if the second difference is not within the second error interval, obtaining a second updated hydrogen concentration based on the second updated initial temperature, and calculating the second updated steam partial pressure based on the second updated initial temperature, and repeating the above steps until the second difference is within the second error interval.

[0014] Optionally, obtaining a third preset operating condition curve to determine that there is no need to pay attention to the hydrogen area includes: obtaining the non-combustible hydrogen concentration; calculating the corresponding non-combustible zirconium oxidation fraction based on the non-combustible hydrogen concentration; calculating the corresponding non-combustible hydrogen mole number based on the non-combustible zirconium oxidation fraction; presetting the third initial temperature of the containment under the third preset operating condition, calculating the non-combustible hydrogen partial pressure by the non-combustible hydrogen mole number and the third initial temperature, and calculating the third steam partial pressure according to the third initial temperature; calculating the third air partial pressure by the initial air mole number; obtaining a third carbon monoxide mole number and a third carbon dioxide mole number, and calculating the third carbon monoxide partial pressure according to the third carbon dioxide mole number, and calculating the third carbon dioxide partial pressure according to the third carbon dioxide mole number; calculating the third containment total pressure by the third hydrogen partial pressure, the third steam partial pressure, the third air partial pressure, the third carbon monoxide partial pressure and the third carbon dioxide partial pressure; presetting different third hydrogen concentrations and repeating the above steps to obtain the third preset operating condition curve.

[0015] Optionally, obtaining a third preset operating condition curve to determine that there is no need to pay attention to the hydrogen area also includes: obtaining a third updated initial temperature based on the third hydrogen concentration; judging whether a third difference between the third updated initial temperature and the third initial temperature is within a third error interval, and if the third difference is not within the third error interval, obtaining a third updated hydrogen concentration based on the third updated initial temperature, and calculating the updated steam partial pressure based on the third updated initial temperature, and repeating the above steps until the third difference is within the third error interval.

[0016] Optionally, obtaining a fourth preset operating condition curve to determine a potential hydrogen combustion zone and a potential hydrogen severe challenge zone in the future includes: calculating an intersection hydrogen concentration corresponding to the intersection of the first preset operating condition curve and the second preset operating condition curve; calculating a corresponding intersection zirconium oxidation fraction according to the intersection hydrogen concentration; obtaining a corresponding intersection hydrogen mole number through the intersection zirconium oxidation fraction; presetting a fourth initial temperature of the containment under a fourth preset operating condition, calculating the intersection hydrogen partial pressure through the intersection hydrogen mole number and the fourth initial temperature, and calculating a fourth steam partial pressure according to the fourth initial temperature; calculating a fourth air partial pressure through the initial air mole number; obtaining a fourth carbon monoxide mole number and a fourth carbon dioxide mole number, and calculating a fourth carbon monoxide partial pressure based on the fourth carbon monoxide mole number, and calculating a fourth carbon dioxide partial pressure based on the fourth carbon dioxide mole number; calculating a fourth containment total pressure through the intersection hydrogen partial pressure, the fourth steam partial pressure, the fourth air partial pressure, the fourth carbon monoxide partial pressure, and the fourth carbon dioxide partial pressure; presetting different fourth hydrogen concentrations and repeating the above steps to obtain the fourth preset operating condition curve.

[0017] Optionally, obtaining a fourth preset operating condition curve to determine a potential hydrogen combustion zone and a potential hydrogen severe challenge zone in the future also includes: updating a fourth updated initial temperature according to the fourth hydrogen concentration; determining whether a fourth difference between the fourth updated initial temperature and the fourth initial temperature is within a fourth error interval, and if the fourth difference is not within the fourth error interval, obtaining a fourth updated hydrogen concentration according to the fourth updated initial temperature, and calculating the updated steam partial pressure according to the fourth updated initial temperature, and repeating the above steps until the fourth difference is within the fourth error interval.

[0018] To solve the above technical problems, the present application provides a risk auxiliary map generation system, comprising: a memory for storing instructions executable by a processor; and a processor for executing the instructions to implement the method as described above.

[0019] In order to solve the above technical problem, the present application provides a computer-readable medium storing a computer program code, and the computer program code implements the above method when executed by a processor.

[0020] Compared with the prior art, the present application presets different operating conditions and obtains the relationship curve between hydrogen concentration and total containment pressure under different operating conditions, which can help nuclear power plant personnel to evaluate hydrogen risks and make mitigation decisions based on nuclear power plant status parameters when an accident occurs. At the same time, in order to reduce the operator's load, the present application can comprehensively consider hydrogen production factors such as zirconium-water reaction and interaction between molten material and concrete, and can evaluate the hydrogen risk of the containment under various operating conditions. It can help personnel evaluate hydrogen risks and make mitigation decisions based on risk auxiliary diagrams, thereby further ensuring the safety and reliability of nuclear reactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0022] Figure 1 It is a flowchart of a method for generating a risk auxiliary map in one embodiment of the present application;

[0023] Figure 2 A risk auxiliary map is produced using a risk auxiliary map generation method in an embodiment of the present application;

[0024] Figure 3 It is a schematic diagram of the structural modules of a risk auxiliary map generation system in one embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0026] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0027] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0028] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0029] This application refers to Figure 1 A method 10 for generating a risk auxiliary map (hereinafter referred to as generation method 10) is proposed, which is applicable to a nuclear reactor, wherein the nuclear reactor includes a containment shell, and the nuclear reactor is suitable for risk assessment through the risk auxiliary map generation method proposed in any embodiment of the present application, such as the above-mentioned generation method 10. Figure 1 A schematic flow diagram of a generation method 10 is shown. A flow diagram is used in the present application to illustrate the operations performed by the system according to an embodiment of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0030] Specifically, we will now combine Figure 1 and Figure 2 Steps S1 to S5 are described in detail, wherein: Figure 2 For the risk auxiliary map produced using the generation method 10, Figure 2The horizontal axis is the containment pressure, and its unit is kPa (g), and the vertical axis is the hydrogen concentration, and its unit is %. The generation method 10 includes steps S1 to S5, wherein S1 includes calculating the initial number of moles of air inside the containment in the initial state; S2 includes obtaining a first preset operating condition curve to determine a hydrogen non-flammable zone A0 (including a hydrogen zone A1 that does not need to be concerned, a zone A2 that may potentially cause hydrogen combustion in the future, and a zone A3 that may potentially cause serious hydrogen challenges in the future); S3 includes obtaining a second preset operating condition curve to determine a hydrogen serious challenge zone A4 and a hydrogen combustion zone A5; S4 includes obtaining a third preset operating condition curve to determine a hydrogen zone A1 that does not need to be concerned; S5 includes obtaining a fourth preset operating condition curve to determine a hydrogen combustion zone A2 that may potentially cause hydrogen combustion in the future, and a zone A3 that may potentially cause serious hydrogen challenges in the future.

[0031] Furthermore, there is no need to pay attention to the hydrogen zone A1, which is an area where the hydrogen concentration is always below the combustion limit, so there is no need to pay attention to the hydrogen risk in the containment. The containment atmosphere in the potential hydrogen combustion zone A2 and the potential hydrogen severe challenge zone A3 is currently in a steam inerting state, and there is no hydrogen risk, but as the steam concentration decreases, it may enter the flammable area or severe challenge area in the future. The hydrogen severe challenge zone A4 and the hydrogen combustion zone A5 are areas where the hydrogen concentration and steam concentration reach the combustion limit, among which the hydrogen severe challenge zone A4 is an area where hydrogen is burned as a whole, causing the containment to pressurize and thus cause the containment to fail.

[0032] First, step S1 includes calculating the initial number of moles of air inside the containment under the initial state, wherein the initial state is the state of the containment when the nuclear reactor is operating normally, and the gas in the containment at this time only includes air and steam, and step S1 only obtains the number of moles of air in the containment under the initial state.

[0033] Further, step S1 mainly includes presetting the initial total pressure and initial temperature of the containment, obtaining the initial steam partial pressure inside the containment through the initial temperature of the containment, and at this time, the atmosphere inside the containment can be preset as an ideal gas with a uniform mixture, and the humidity of the atmosphere in the containment is 100%, and the temperature inside the containment corresponds to the saturation temperature of the steam partial pressure. Exemplarily, the initial steam partial pressure of steam in a saturated state can be obtained by looking up a table or an empirical relationship. Since the inside of the containment in the initial state only includes steam and air, the initial air partial pressure inside the containment can be obtained by subtracting the initial steam partial pressure from the preset initial total pressure of the containment. After the initial air partial pressure is obtained, the initial air molar number can be calculated based on the initial air partial pressure. In this embodiment, preferably, if there is a situation where the containment is exhausted, it is assumed that the gas components are released in the same proportion as in the containment during exhaust, so the influence of the exhaust share is taken into account when calculating the initial molar number of air.

[0034] Exemplarily, the initial number of moles of air can be calculated by the following formula:

[0035]

[0036] Where V is the volume of the containment, P a0 is the partial pressure of air, R is the ideal gas constant, which is generally 8.31 J / (mol·K), T0 is the initial temperature, and f vent is the exhaust share of the containment, C is a conservative coefficient, and its value generally ranges from 1 to 1.1.

[0037] On the other hand, step S2 is to obtain the first preset operating condition curve to determine the hydrogen non-flammable area. In this embodiment, the first preset operating condition is an inert condition. Since the flammability of hydrogen in the containment is closely related to the steam concentration, when the steam concentration in the hydrogen-air-steam mixture is higher than a certain value, an inert condition will be formed so that hydrogen cannot burn. In addition to the production of hydrogen by the zirconium-water reaction, if the molten material penetrates the pressure vessel in the nuclear reactor and falls to the bottom plate of the reactor cavity, it will interact with the concrete (i.e., MCCI), and additional hydrogen, carbon monoxide, carbon dioxide and other gases will be produced. Step S2 will take the above situation into consideration to prepare a risk auxiliary map.

[0038] Specifically, step S2 mainly includes presetting a first total pressure and a first initial temperature of the containment under a first preset operating condition, and calculating a first steam partial pressure according to the first initial temperature. Similar to step S1, the first steam partial pressure of steam at the first initial temperature can be obtained by looking up a table or an empirical relationship, and the first air partial pressure can be calculated by the initial air molar number.

[0039] Exemplarily, the first air partial pressure may be calculated by the following formula:

[0040]

[0041] Among them, P ancombst is the partial pressure of containment air under inert conditions, n air is the initial number of moles of air, V is the volume of the containment, R is the ideal gas constant, which is generally 8.31 J / (mol·K), T ncombst is the preset first initial temperature.

[0042] Further, step S2 includes obtaining a first carbon monoxide mole number and a first carbon dioxide mole number. At this time, the first carbon monoxide mole number and the first carbon dioxide mole number can be obtained according to the actual situation, which is divided into the phenomenon of MCCI occurring and the phenomenon of MCCI not occurring. In this embodiment, the situation where the MCCI phenomenon occurs is considered, and the first carbon monoxide mole number and the first carbon dioxide mole number can be obtained based on experience when MCCI occurs. In other embodiments of the present application, if the phenomenon of MCCI occurring is not considered, the first carbon monoxide mole number and the first carbon dioxide mole number are 0.

[0043] Step S2 further includes calculating a first carbon monoxide partial pressure according to the first carbon monoxide mole number, and calculating a first carbon dioxide partial pressure according to the first carbon dioxide mole number. Exemplarily, the first carbon monoxide partial pressure can be calculated by the following formula:

[0044]

[0045] Among them, P COncombst is the first carbon monoxide partial pressure in the containment under inert conditions, n CO is the first mole of carbon monoxide, V is the volume of the containment, R is the ideal gas constant, which is generally 8.31 J / (mol·K), T ncombst is the preset first initial temperature.

[0046] Furthermore, the first carbon dioxide partial pressure can be calculated by the following formula:

[0047]

[0048] in, is the first carbon dioxide partial pressure of the containment under inerting conditions, is the first mole of carbon dioxide, V is the volume of the containment, R is the ideal gas constant, which is generally 8.31 J / (mol·K), T ncombst is the preset first initial temperature.

[0049] Furthermore, the first hydrogen partial pressure can be directly obtained according to the preset first total pressure, the obtained first steam partial pressure, the first air partial pressure, the first carbon monoxide partial pressure and the first carbon dioxide partial pressure. That is, the first hydrogen partial pressure is equal to the first total pressure minus the first steam partial pressure, the first air partial pressure, the first carbon monoxide partial pressure and the first carbon dioxide partial pressure.

[0050] Next, the first hydrogen concentration can be calculated by the first hydrogen partial pressure. The first hydrogen concentration is the ratio of the first hydrogen partial pressure to the first total pressure, that is:

[0051]

[0052] Among them, fHnc is the first hydrogen concentration, P Hncombst is the first hydrogen partial pressure, and P is the first total pressure.

[0053] Finally, different first total pressures can be preset and the above steps can be repeated to obtain the first hydrogen concentration under different first total pressures, so as to obtain Figure 2 The first preset operating condition curve a is shown, and the lower right side of the first preset operating condition curve a is the non-flammable area A0.

[0054] Furthermore, step S2 also includes calculating and updating the steam partial pressure according to the first hydrogen concentration. To calculate and update the steam partial pressure according to the first hydrogen concentration, the combustible gas concentration needs to be obtained first. Since the combustible gas includes carbon monoxide and hydrogen at this time, the combustible gas concentration is equal to the ratio of the sum of the first carbon monoxide partial pressure and the hydrogen partial pressure to the first total pressure, that is:

[0055]

[0056] Among them, is f CHnC Combustible gas concentration, P Hncombst is the first hydrogen partial pressure, P COncombst is the first carbon monoxide partial pressure, and P is the first total pressure.

[0057] Furthermore, it is known from existing experience that the relationship between the first hydrogen concentration and the renewal steam partial pressure under inert conditions is:

[0058] g(f CHnc )=f(P sncombst ,P)

[0059] The updated steam partial pressure can be obtained by the first hydrogen concentration. After knowing the updated steam partial pressure, the updated initial temperature corresponding to the updated steam partial pressure can be obtained by reverse calculation based on the table lookup and the empirical relationship. Then, it is further determined whether the first difference between the updated initial temperature and the first initial temperature is within the first error interval. If the first difference is not within the first error interval, it means that there is a deviation in the preset of the first initial temperature. Then, it is necessary to obtain the updated hydrogen concentration according to the above steps based on the updated initial temperature, and calculate the updated steam partial pressure according to the updated hydrogen concentration. According to the updated steam partial pressure, the updated initial temperature corresponding to the updated steam partial pressure is obtained again, and the above steps are repeated until the first difference is within the first error interval. In this embodiment, preferably, all calculation steps in step S2 can be calculated with the help of a computer program.

[0060] In this embodiment, step S3 is to obtain a second preset operating condition curve to determine the hydrogen severe challenge zone and the hydrogen combustion zone. Exemplarily, the second preset operating condition is a containment failure condition. At this time, hydrogen combustion causes the containment to be pressurized. It is conservatively assumed that the hydrogen combustion process is a simplified adiabatic isochoric complete combustion (AICC) to make the containment pressure the highest.

[0061] Specifically, step S3 mainly includes presetting the total pre-combustion pressure and the initial pre-combustion temperature of the containment under the second preset operating condition, and calculating the pre-combustion steam partial pressure according to the initial pre-combustion temperature; calculating the pre-combustion air partial pressure by the initial air mole number; obtaining the carbon monoxide mole number before combustion and the carbon dioxide mole number before combustion, and calculating the carbon monoxide partial pressure before combustion according to the carbon monoxide mole number before combustion, and calculating the carbon dioxide partial pressure before combustion according to the carbon dioxide mole number before combustion; calculating the pre-combustion hydrogen partial pressure according to the total pre-combustion pressure, the steam partial pressure before combustion, the air partial pressure before combustion, the carbon monoxide partial pressure before combustion and the carbon dioxide partial pressure before combustion; calculating the pre-combustion hydrogen concentration by the hydrogen partial pressure before combustion; presetting a different second total pressure and repeating the above steps to obtain a second preset operating condition curve.

[0062] First, the total pressure before combustion and the initial temperature before combustion of the containment under the second preset working condition can be preset, and the steam partial pressure before combustion, the air partial pressure before combustion, the molar number of carbon monoxide before combustion, the molar number of carbon dioxide before combustion, the carbon monoxide partial pressure before combustion, the carbon dioxide partial pressure before combustion, the hydrogen partial pressure before combustion, and the hydrogen concentration before combustion can be calculated with reference to the method of step S2. Finally, the above steps can be repeated by presetting different total pressures before combustion to obtain the hydrogen concentration before combustion under different total pressures before combustion, so as to obtain the following: Figure 2 The second preset operating condition curve b shown. Figure 2 As shown, the second preset operating condition curve b and the first preset operating condition curve a divide two areas, wherein the area divided by the lower side of the second preset operating condition curve b and the upper side of the first preset operating condition curve a is the hydrogen combustion area A5, and the area divided by the upper side of the second preset operating condition curve b and the left side of the first preset operating condition curve a is the hydrogen severe challenge area A4. Further, step S3 also includes calculating the total molar number of the containment before combustion according to the hydrogen partial pressure before combustion. Exemplarily, the total molar number of the containment before combustion can be calculated by the following formula:

[0063]

[0064] Among them, n pre is the total molar number of the containment before combustion, P is the total pressure of the containment before combustion, R is the ideal gas constant, which is generally taken as 8.31 J / (mol·K), T chall is the initial temperature before combustion.

[0065] Afterwards, the total moles of the containment after combustion, the moles of steam after combustion, the moles of air after combustion, and the moles of carbon dioxide after combustion can be calculated by the hydrogen combustion reaction. Specifically, assuming that hydrogen and carbon monoxide are completely consumed during AICC combustion, and the energy generated is completely absorbed by the containment atmosphere, then the moles of hydrogen and carbon monoxide before combustion are known, and the total moles of the containment after combustion can be calculated by the following formula:

[0066] n post =n pre -0.5×n Hpre -0.5×n COpre

[0067] Among them, n post is the total mole number of the containment after combustion, n Hpre is the number of moles of hydrogen before combustion, n COpre is the number of moles of carbon monoxide before combustion.

[0068] Furthermore, according to the law of conservation of energy, that is, the energy absorbed by air, carbon dioxide and steam is equal to the energy released by the combustion of hydrogen and carbon monoxide, the temperature rise of the containment after combustion can be obtained. In the calculation of the containment failure condition, according to the pressure after AICC combustion is equal to the containment failure pressure, the second updated initial temperature T under the containment failure condition can be obtained according to the formula new :

[0069]

[0070] Where P is the containment pressure before combustion, P chall is the failure pressure of the containment, ΔT is the temperature rise of the containment. Determine the second updated initial temperature T new and whether the second difference between the initial temperature before combustion is within the second error interval. If the second difference is not within the second error interval, the second updated hydrogen concentration is obtained according to the second updated initial temperature, and the second updated steam partial pressure is calculated according to the second updated initial temperature, and the above steps are repeated until the second difference is within the second error interval. In this embodiment, all calculation steps in step S3 can be completed by calculation with the help of a computer program.

[0071] On the other hand, step S4 includes obtaining a third preset operating condition curve to determine that there is no need to pay attention to the hydrogen area. Step S4 mainly includes obtaining the non-combustible concentration of hydrogen. Since the containment atmosphere in the non-combustible area is in a steam inerting state, it may become a combustible area as the steam concentration decreases. Therefore, it is generally believed that the hydrogen volume concentration is less than 4% and will not be ignited. Therefore, the non-combustible concentration of hydrogen under the third preset operating condition is 4%.

[0072] Furthermore, based on experience, the corresponding non-combustible zirconium oxidation fraction can be calculated by the non-combustible hydrogen concentration, and then the corresponding non-combustible hydrogen mole number can be calculated based on the non-combustible zirconium oxidation fraction. For example, the corresponding hydrogen mole number can be calculated based on the zirconium oxidation fraction using the following formula:

[0073]

[0074] Among them, f x is the zirconium oxidation fraction, m zr is the mass of zirconium, M zr is the molar mass of zirconium, f vent is the exhaust share of the containment, which are all known quantities. Therefore, the number of moles of incombustible hydrogen corresponding to the incombustible zirconium oxidation share can be calculated by the above formula.

[0075] Further, step S4 also includes presetting a third initial temperature of the containment under the third preset working condition, calculating the non-combustible hydrogen partial pressure (i.e., the third hydrogen partial pressure) by the non-combustible hydrogen mole number and the third initial temperature, and calculating the third steam partial pressure according to the third initial temperature; calculating the third air partial pressure by the initial air mole number; obtaining the third carbon monoxide mole number and the third carbon dioxide mole number, and calculating the third carbon monoxide partial pressure according to the third carbon monoxide mole number, and calculating the third carbon dioxide partial pressure according to the third carbon dioxide mole number. The specific solution method can refer to step 2, and will not be repeated here.

[0076] Next, the third containment total pressure is calculated by the third hydrogen partial pressure, the third steam partial pressure, the third air partial pressure, the third carbon monoxide partial pressure and the third carbon dioxide partial pressure, that is, the third containment total pressure is equal to the sum of the third hydrogen partial pressure, the third steam partial pressure, the third air partial pressure, the third carbon monoxide partial pressure and the third carbon dioxide partial pressure. Preset different third hydrogen concentrations and repeat the above steps to obtain Figure 2 The third preset operating condition curve c is shown, wherein the lower area of ​​the third preset operating condition curve c is the hydrogen area A1 that does not need to be paid attention to.

[0077] On the other hand, step S4 also includes obtaining a third updated initial temperature according to the third hydrogen concentration. The specific method can refer to step S2 and will not be described in detail here. It is determined whether the third difference between the third updated initial temperature and the third initial temperature is within the third error interval. If the third difference is not within the third error interval, the third updated hydrogen concentration is obtained according to the third updated initial temperature, and the updated steam partial pressure is calculated according to the third updated initial temperature. The above steps are repeated until the third difference is within the third error interval. In this embodiment, all calculation steps in step S4 can be calculated by a computer program.

[0078] In this embodiment, step S5 is to obtain a fourth preset operating condition curve to determine a potential hydrogen combustion zone and a potential hydrogen severe challenge zone in the future. Step S5 mainly includes calculating the intersection hydrogen concentration corresponding to the intersection of the first preset operating condition curve and the second preset operating condition curve, and calculating the corresponding intersection zirconium oxidation fraction according to the intersection hydrogen concentration. In this embodiment, preferably, all calculation steps in step S5 can be completed by computer program calculation.

[0079] Further, the corresponding intersection hydrogen mole number can be obtained by the intersection zirconium oxidation fraction with reference to step S4. Afterwards, similar to step S4, reference can be made to step S2, the fourth initial temperature of the containment under the fourth preset working condition is preset, the intersection hydrogen partial pressure is calculated by the intersection hydrogen mole number and the fourth initial temperature, and the fourth steam partial pressure is calculated according to the fourth initial temperature; the fourth air partial pressure is calculated by the initial air mole number; the fourth carbon monoxide mole number and the fourth carbon dioxide mole number are obtained, and the fourth carbon monoxide partial pressure is calculated according to the fourth carbon dioxide mole number, and the fourth carbon dioxide partial pressure is calculated according to the fourth carbon dioxide mole number; the fourth containment total pressure is calculated by the intersection hydrogen partial pressure, the fourth steam partial pressure, the fourth air partial pressure, the fourth carbon monoxide partial pressure and the fourth carbon dioxide partial pressure.

[0080] Furthermore, a fourth preset hydrogen concentration is preset and the above steps are repeated to obtain a fourth preset operating condition curve d. The upper side of the fourth preset operating condition curve d and the right side of the first preset operating condition curve a form a hydrogen severe challenge area A3, and the lower side of the fourth preset operating condition curve d, the lower side of the first preset operating condition curve a, and the upper side of the third preset operating condition curve c form an area A2 where hydrogen combustion may potentially occur in the future.

[0081] Furthermore, step S5 also includes obtaining a fourth updated initial temperature based on the hydrogen concentration; determining whether a fourth difference between the fourth updated initial temperature and the fourth initial temperature is within a fourth error interval; if the fourth difference is not within the fourth error interval, obtaining a fourth updated hydrogen concentration based on the fourth updated initial temperature, and calculating an updated steam partial pressure based on the fourth updated initial temperature, and repeating the above steps until the fourth difference is within the fourth error interval.

[0082] On the other hand, the generation method 10 also includes setting different zirconium water oxidation fractions to obtain zirconium water reaction curves. Specifically, in this embodiment, the zirconium water reaction curve e with a zirconium water oxidation fraction of 25%, the zirconium water reaction curve f with a zirconium water oxidation fraction of 50%, and the zirconium water reaction curve g with a zirconium water oxidation fraction of 75% can be obtained with reference to step S4.

[0083] An embodiment of the present application also proposes a method such as Figure 3 The risk auxiliary map generation system 30 shown. Figure 3The risk auxiliary map generation system 30 may include an internal communication bus 31, a processor 32, a read-only memory (ROM) 33, a random access memory (RAM) 34, and a communication port 35. When applied on a personal computer, the risk auxiliary map generation system 30 may also include a hard disk 36.

[0084] The internal communication bus 31 can realize data communication between components of the risk auxiliary map generation system 30. The processor 32 can make judgments and issue prompts. In some embodiments, the processor 32 can be composed of one or more processors. The communication port 35 can realize data communication between the risk auxiliary map generation system 30 and the outside. In some embodiments, the risk auxiliary map generation system 30 can send and receive information and data from the network through the communication port 35.

[0085] The risk auxiliary map generation system 30 may also include different forms of program storage units and data storage units, such as a hard disk 56, a read-only memory (ROM) 53 and a random access memory (RAM) 54, which can store various data files used for computer processing and / or communication, and possible program instructions executed by the processor 52. The processor executes these instructions to implement the main part of the method. The results of the processor processing are transmitted to the user device through the communication port and displayed on the user interface.

[0086] In addition, the present application also proposes a computer-readable medium storing a computer program code, and the computer program code implements the above-mentioned risk auxiliary map generation method when executed by a processor.

[0087] By presetting different operating conditions and calculating the relationship curve between hydrogen concentration and total containment pressure under different operating conditions, the present application can help nuclear power plant personnel to assess hydrogen risks and make mitigation decisions based on nuclear power plant status parameters when an accident occurs. At the same time, in order to reduce the operator's load, the present application can comprehensively consider hydrogen production factors such as zirconium-water reaction and interaction between molten material and concrete, assess the hydrogen risk of the containment under various operating conditions, and help personnel assess hydrogen risks and make mitigation decisions based on risk auxiliary diagrams, thereby further ensuring the safety and reliability of nuclear reactors.

[0088] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0089] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0090] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more application embodiments, in the above description of the embodiments of this application, multiple features are sometimes merged into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0091] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0092] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A method for generating a risk auxiliary map, applicable to a nuclear reactor, wherein the nuclear reactor includes a containment vessel, characterized in that: The generation method comprises the following steps: Calculating the initial number of moles of air inside the containment vessel in an initial state; Obtaining a first preset operating condition curve to determine a hydrogen non-flammable region; Obtaining a second preset operating condition curve to determine a hydrogen severe challenge zone and a hydrogen combustion zone; Obtaining a third preset operating condition curve to determine a hydrogen region that does not require attention; A fourth preset operating condition curve is obtained to determine a potential hydrogen combustion zone and a potential hydrogen severe challenge zone in the future.

2. The generation method according to claim 1, characterized in that: It also includes setting different zirconium water oxidation ratios to obtain a zirconium water reaction curve.

3. The generation method according to claim 1, characterized in that: Calculating the number of moles of air inside the containment vessel in the initial state includes: Presetting the initial total pressure and initial temperature of the containment vessel; Obtaining an initial steam partial pressure inside the containment shell according to the initial temperature of the containment shell; Calculating an initial air partial pressure inside the containment according to the initial total pressure of the containment and the initial steam partial pressure; The initial number of moles of air is calculated based on the initial air partial pressure.

4. The generation method according to claim 3, characterized in that: It also includes calculating the initial number of moles of air by the following formula: Wherein, V is the volume of the containment, P a0 is the air partial pressure, R is the ideal gas constant, T0 is the initial temperature, f vent is the exhaust share of the containment, and C is the conservative coefficient.

5. The generation method according to claim 1, characterized in that: Obtaining a first preset operating condition curve to determine a hydrogen non-flammable region includes: Presetting a first total pressure and a first initial temperature of the containment under a first preset operating condition, and calculating a first steam partial pressure according to the first initial temperature; Calculating a first air partial pressure based on the initial number of air moles; Obtaining a first carbon monoxide mole number and a first carbon dioxide mole number, and calculating a first carbon monoxide partial pressure according to the first carbon monoxide mole number, and calculating a first carbon dioxide partial pressure according to the first carbon dioxide mole number; calculating a first hydrogen partial pressure based on the first total pressure, the first steam partial pressure, the first air partial pressure, the first carbon monoxide partial pressure, and the first carbon dioxide partial pressure; Calculating a first hydrogen concentration according to the first hydrogen partial pressure; Preset different first total pressures and repeat the above steps to obtain the first preset operating condition curve.

6. The generation method according to claim 5, characterized in that: Obtaining the first preset operating condition curve to determine the hydrogen non-flammable region also includes: Calculate and update the steam partial pressure according to the first hydrogen concentration; Obtaining an updated initial temperature according to the updated steam partial pressure; Determine whether a first difference between the updated initial temperature and the first initial temperature is within a first error interval; if the first difference is not within the first error interval, obtain an updated hydrogen concentration based on the updated initial temperature, and calculate the updated steam partial pressure based on the updated hydrogen concentration, and repeat the above steps until the first difference is within the first error interval.

7. The generation method according to claim 1, characterized in that: Obtaining the second preset operating condition curve to determine the hydrogen severe challenge area and the hydrogen combustion area includes: Presetting the total pressure before combustion and the initial temperature before combustion of the containment under the second preset working condition, and calculating the partial pressure of steam before combustion according to the initial temperature before combustion; Calculate the partial pressure of air before combustion by the initial number of moles of air; Obtaining the number of moles of carbon monoxide before combustion and the number of moles of carbon dioxide before combustion, and calculating the partial pressure of carbon monoxide before combustion according to the number of moles of carbon monoxide before combustion, and calculating the partial pressure of carbon dioxide before combustion according to the number of moles of carbon dioxide before combustion; Calculating the pre-combustion hydrogen partial pressure based on the pre-combustion total pressure, the pre-combustion steam partial pressure, the pre-combustion air partial pressure, the pre-combustion carbon monoxide partial pressure, and the pre-combustion carbon dioxide partial pressure; Calculating the pre-combustion hydrogen concentration by the pre-combustion hydrogen partial pressure; A different second total pressure is preset and the above steps are repeated to obtain the second preset operating condition curve.

8. The generation method according to claim 7, characterized in that: Obtaining a second preset operating condition curve to determine a hydrogen severe challenge zone and a hydrogen combustion zone also includes: Calculating the total number of moles of the containment before combustion based on the hydrogen partial pressure before combustion; Under the condition that hydrogen and carbon monoxide are completely exhausted, the total mole number of the containment after combustion, the mole number of steam after combustion and the mole number of air after combustion are calculated; according to the conservation of combustion energy, the temperature rise of the containment after combustion is calculated; the second updated initial temperature is calculated according to the total mole number of the containment before combustion, the total mole number of the containment after combustion, the temperature rise, the failure pressure of the containment and the total pressure of the containment before combustion; Determine whether a second difference between the second updated initial temperature and the pre-combustion initial temperature is within a second error interval; if the second difference is not within the second error interval, obtain a second updated hydrogen concentration based on the second updated initial temperature, and calculate the second updated steam partial pressure based on the second updated initial temperature, and repeat the above steps until the second difference is within the second error interval.

9. The generation method according to claim 1, characterized in that: Obtaining the third preset operating condition curve to determine the hydrogen region that does not require attention includes: Obtain the non-flammable concentration of hydrogen; Calculating a corresponding non-combustible zirconium oxidation fraction according to the non-combustible concentration of hydrogen; Calculating the corresponding number of moles of incombustible hydrogen according to the incombustible zirconium oxidation fraction; Presetting a third initial temperature of the containment under a third preset operating condition, calculating the non-combustible hydrogen partial pressure according to the non-combustible hydrogen mole number and the third initial temperature, and calculating a third steam partial pressure according to the third initial temperature; Calculating a third air partial pressure according to the initial number of air moles; Obtaining a third carbon monoxide mole number and a third carbon dioxide mole number, and calculating a third carbon monoxide partial pressure according to the third carbon monoxide mole number, and calculating a third carbon dioxide partial pressure according to the third carbon dioxide mole number; calculating a third containment total pressure according to a third hydrogen partial pressure, the third steam partial pressure, the third air partial pressure, the third carbon monoxide partial pressure, and the third carbon dioxide partial pressure; A different third hydrogen concentration is preset and the above steps are repeated to obtain the third preset operating condition curve.

10. The generation method according to claim 9, characterized in that: Obtaining the third preset operating condition curve to determine the hydrogen region that does not require attention also includes: acquiring a third updated initial temperature according to the third steam partial pressure; Determine whether a third difference between the third updated initial temperature and the third initial temperature is within a third error interval; if the third difference is not within the third error interval, obtain a third updated hydrogen concentration according to the third updated initial temperature, and calculate the updated steam partial pressure according to the third updated initial temperature, and repeat the above steps until the third difference is within the third error interval.

11. The generation method according to claim 1, characterized in that: Obtaining the fourth preset operating condition curve to determine the potential hydrogen combustion zone and the potential hydrogen severe challenge zone in the future includes: Calculating the hydrogen concentration and the containment pressure at the intersection point corresponding to the intersection point of the first preset operating condition curve and the second preset operating condition curve; Calculating the corresponding intersection zirconium oxidation fraction according to the intersection hydrogen concentration and the containment pressure; Calculate the corresponding number of moles of hydrogen at the intersection by using the zirconium oxidation fraction at the intersection; Presetting a fourth initial temperature of the containment under a fourth preset operating condition, calculating the intersection hydrogen partial pressure by the intersection hydrogen mole number and the fourth initial temperature, and calculating a fourth steam partial pressure according to the fourth initial temperature; Calculating a fourth air partial pressure according to the initial number of air moles; Obtaining a fourth mole number of carbon monoxide and a fourth mole number of carbon dioxide, and calculating a fourth carbon monoxide partial pressure according to the fourth mole number of carbon monoxide, and calculating a fourth carbon dioxide partial pressure according to the fourth mole number of carbon dioxide; Calculate the fourth containment total pressure by using the intersection hydrogen partial pressure, the fourth steam partial pressure, the fourth air partial pressure, the fourth carbon monoxide partial pressure, and the fourth carbon dioxide partial pressure; A fourth preset hydrogen concentration is preset and the above steps are repeated to obtain the fourth preset operating condition curve.

12. The generation method according to claim 11, characterized in that: Obtaining the fourth preset operating condition curve to determine the potential hydrogen combustion zone and the potential hydrogen severe challenge zone in the future also includes: updating a fourth updated initial temperature according to the fourth hydrogen concentration; Determine whether a fourth difference between the fourth updated initial temperature and the fourth initial temperature is within a fourth error interval; if the fourth difference is not within the fourth error interval, obtain a fourth updated hydrogen concentration according to the fourth updated initial temperature, and calculate the updated steam partial pressure according to the fourth updated initial temperature, and repeat the above steps until the fourth difference is within the fourth error interval.

13. A risk auxiliary graph generation system, comprising: a memory for storing instructions executable by a processor; and a processor, configured to execute the instructions to implement the method according to any one of claims 1 to 12.

14. A computer readable medium storing computer program code, wherein the computer program code, when executed by a processor, implements the method according to any one of claims 1 to 12.

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