Active power regulation method and system for nuclear reactor based on main heat exchanger system

Abstract

The present invention discloses a method and system for actively regulating the power of a nuclear reactor based on a main heat exchanger system, which relates to the technical field of nuclear reactor control and includes the following steps: according to the required core output power of the nuclear reactor, matching and calculating the coolant flow rate and coolant temperature after passing through the core of the nuclear reactor, and pre-distributing the heat exchange power of each heat exchanger connected to the output end of the core of the nuclear reactor; checking the flow rate of the coolant required by each heat exchanger to obtain the flow rate set value and the coolant outlet temperature set value of each heat exchanger; distributing the coolant flowing out of the core of the nuclear reactor to each heat exchanger; making the flow rate of the coolant flowing into each heat exchanger equal to the flow rate set value of the heat exchanger, and the actual coolant outlet temperature of each heat exchanger reach the coolant outlet temperature set value of the heat exchanger. The present invention enables the power of the reactor to be step-by-step coupled with the power of the main heat exchanger system, realizing the active control of the reactor power.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear reactor control, and specifically to an active power regulation method and system for a nuclear reactor based on a primary heat exchanger system. Background Art

[0002] The power regulation of a reactor is achieved by changing the reactivity, and generally, movable control rods are used to regulate the reactivity. The rising and insertion depth of the control rods are adjusted through mechanical devices to control the amount of neutrons absorbed in the reactor, thereby changing the power of the reactor core. Traditional reactor power regulation usually adjusts the insertion depth of the control rods according to the deviation signal between the actual power of the reactor and the set power. The most common is to use a proportional-integral-derivative controller (PID) to achieve this.

[0003] The PID controller is provided with two channels: feedforward control of the heat load and feedback control of the average coolant temperature. The former uses the deviation between the set power and the actual measured power of the reactor as a signal to adjust the control rods, and the latter uses the deviation between the set value and the measured value of the average coolant temperature as a signal to adjust the control rods. This traditional reactor power regulation method can reduce the error between the actual power and the set power of the reactor by eliminating the deviation after setting the reactor thermal power, which can be considered as passive regulation of the reactor power.

[0004] During the operation of the reactor, sometimes it is necessary to adjust the power of the reactor to a specific value to ensure the safety of the reactor. For example, when the primary heat exchanger is damaged and needs to be replaced. At this time, it is necessary to distribute the coolant flow to other primary heat exchangers, and the outlet coolant temperature will inevitably change. Therefore, it is necessary to actively adjust the depth of the control rods to be coupled with the changes in the primary heat exchanger system to match the power changes of the primary heat exchanger system and ensure the safety of the reactor. This method can be considered as active regulation of the reactor power.

[0005] The traditional passive reactor power regulation method does not consider the matching problem between the reactor power and the primary heat exchanger system, and only takes the coolant temperature as an input signal for passive regulation. Summary of the Invention

[0006] The present invention proposes an active power regulation method for a nuclear reactor based on a primary heat exchanger system. By obtaining specific core coolant flow rate and temperature, and synchronously calculating the structural changes of the core and the rod positions of the control rods, the power of the reactor is step by step coupled with the power of the primary heat exchanger system to achieve the purpose of actively controlling the reactor power.

[0007] The present invention provides an active power regulation method for a nuclear reactor based on a primary heat exchanger system, including the following steps:

[0008] According to the output power of the core of the required nuclear reactor, match and calculate the coolant flow rate and coolant temperature after passing through the core of the nuclear reactor;

[0009] According to the coolant flow rate and coolant temperature after passing through the core of the nuclear reactor, pre-distribute the heat transfer power of each heat exchanger connected to the output end of the core of the nuclear reactor;

[0010] According to the coolant temperature flowing into each heat exchanger and the heat transfer power of each heat exchanger, calculate the flow rate of the coolant required for each heat exchanger to obtain the flow rate setting value and the coolant outlet temperature setting value of each heat exchanger;

[0011] Distribute the coolant flowing out of the core of the nuclear reactor to each heat exchanger;

[0012] Monitor the flow rate of each heat exchanger after operation, make the flow rate of the coolant flowing into each heat exchanger equal to the flow rate setting value of the heat exchanger, and ensure that the actual coolant outlet temperature of each heat exchanger reaches the coolant outlet temperature setting value of the heat exchanger by fine-tuning the flow rate of each heat exchanger after operation;

[0013] According to the coolant flow rate at the inlet of each heat exchanger after fine-tuning, determine the actual coolant flow rate passing through the core of the nuclear reactor to achieve the regulation of the output power of the core of the nuclear reactor.

[0014] Further, the calculating the flow rate of the coolant required for each heat exchanger according to the coolant temperature flowing into each heat exchanger and the heat transfer power of each heat exchanger includes:

[0015] Pre-set the structural parameters of each heat exchanger;

[0016] Pre-assume the coolant flow rate of each heat exchanger;

[0017] According to the coolant temperature flowing into each heat exchanger, call the physical property functions and heat transfer correlation formulas of the coolant fluids on both sides of each heat exchanger, and calculate the coolant outlet temperature T2 of each heat exchanger according to the heat balance equation;

[0018] When the absolute value of the difference between the coolant outlet temperature T2 of each heat exchanger and the coolant inlet temperature T1 of the core of the nuclear reactor is less than a certain value, take the pre-assumed coolant flow rate of each heat exchanger as the flow rate setting value of the coolant of each heat exchanger, and take the coolant outlet temperature T2 of each heat exchanger as the coolant outlet temperature setting value of each heat exchanger.

[0019] Further, it also includes calculating and checking the actual coolant flow rate of each heat exchanger according to the relationship between the heat transfer equation and the heat balance equation, and setting the minimum flow velocity of the fluid in the heat exchanger;

[0020] Determine the actual flow velocity of the fluid in the heat exchanger according to the actually calculated coolant flow rate of the fluid in the heat exchanger. When the actual flow velocity of the fluid in the heat exchanger is less than the minimum flow velocity set for the heat exchanger, shut down any one of the heat exchangers in the main heat exchanger module, and recalculate the actual coolant flow rate in the remaining heat exchangers in the main heat exchanger module.

[0021] Furthermore, the method for calculating and verifying the actual coolant flow rate of the heat exchanger according to the relationship between the heat transfer equation and the heat balance equation is as follows:

[0022] Let:

[0023]

[0024] where k is the overall heat transfer coefficient of the heat exchanger, which includes the heat transfer coefficient of the cold fluid surface, the heat transfer coefficient of the hot fluid surface, and the heat conduction of the heat exchanger tube wall;

[0025] A is the total heat transfer area in the heat exchanger, which is obtained from the heat exchanger type and geometric parameters;

[0026] Δt m is the logarithmic mean temperature difference. For a countercurrent heat exchanger, the logarithmic mean temperature difference is:

[0027]

[0028] where Δt max is the maximum temperature difference between the hot and cold fluids at both ends of the heat exchanger; Δt min is the minimum temperature difference between the hot and cold fluids at both ends of the heat exchanger;

[0029] C p is the specific heat capacity at constant pressure of the fluid, which is related to the temperature and pressure of the fluid;

[0030] Δt is the temperature difference between the cold and hot fluids;

[0031] Based on the five known parameters in Equation (1), find the actual coolant flow rate of the heat exchanger

[0032] Furthermore, when it is necessary to change the core output power of the nuclear reactor, the coolant flowing out of the core of the nuclear reactor can be redistributed according to the changed core output power of the nuclear reactor, so that the mass flow rate of the coolant flowing into each heat exchanger changes gradually, the total power of each heat exchanger changes gradually, and is coupled step by step with the change of the core output power of the nuclear reactor, realizing continuous and stable adjustment of the core output power of the nuclear reactor.

[0033] Further, according to the actual coolant outlet temperature of each heat exchanger, the flow rate of the coolant flowing into each heat exchanger is feedback-regulated. By controlling the flow rate of the coolant in each heat exchanger, the dynamic stability of the main heat exchanger module is achieved.

[0034] The present invention provides a nuclear reactor power active regulation system based on a reactor main heat exchanger system, including:

[0035] A main heat exchanger module, which is composed of multiple heat exchangers, and is used for pre-distributing the heat exchange power of each heat exchanger connected to the output end of the core of the nuclear reactor according to the coolant flow rate and coolant temperature after passing through the core of the nuclear reactor.

[0036] A data acquisition module, which is used for acquiring the actual data during the operation of the nuclear reactor, including the coolant inlet temperature of the core of the nuclear reactor, the coolant outlet temperature of the core of the nuclear reactor, the coolant inlet temperature of each heat exchanger in the main heat exchanger module, the coolant outlet temperature of each heat exchanger in the main heat exchanger module, and the coolant flow rate of each heat exchanger in the main heat exchanger module.

[0037] A data calculation and regulation module, which is communicatively connected to the data acquisition module. The data acquisition module sends the actual data acquired during the operation of the nuclear reactor to the data calculation and regulation module. The data calculation and regulation module calculates the flow rate of the coolant required for each heat exchanger according to the coolant temperature flowing into each heat exchanger and the heat exchange power of each heat exchanger, and obtains the flow rate set value and coolant outlet temperature set value of each heat exchanger.

[0038] A flow rate distribution module, which is used for distributing the coolant flowing out of the core of the nuclear reactor to each heat exchanger.

[0039] Further, the flow rate distribution module includes a flow rate distributor, a storage device, and a heating device;

[0040] When the coolant flow rate required by the main heat exchanger module is less than the coolant flow rate flowing out of the core of the nuclear reactor, the flow rate distributor stores the excess coolant in the storage device;

[0041] When the coolant flow rate required by the main heat exchanger module is greater than the coolant flow rate flowing out of the core of the nuclear reactor, the coolant stored in the storage device is heated to a specific temperature by the heating device and then input into the flow rate distributor. After that, the flow rate distributor distributes the flow rate to the main heat exchanger module.

[0042] Further, the input parameters of the heat exchanger calculation module include the heat exchange power of each heat exchanger and the coolant inlet temperature of the heat exchanger, and the output parameters include the coolant flow rate of the heat exchanger.

[0043] Advantages of the present invention compared with the prior art:

[0044] The present invention proposes a method for accurately regulating the flow rate of each heat exchanger in the main heat exchanger system, thereby obtaining specific core coolant flow rate and temperature, and synchronously calculating the structural changes of the core and the rod positions of the control rods, so that the power of the reactor is step by step coupled with the power of the main heat exchanger system to achieve the purpose of actively controlling the reactor power. The present invention makes full use of the main heat exchanger system in the reactor, accurately regulates the flow rate of each heat exchanger in the main heat exchanger system to control the temperature and flow rate of the coolant flowing out of the main heat exchanger system, and regulates the reactivity of the reactor through a calculation program to actively control the power of the reactor. Brief Description of the Drawings

[0045] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0046] Figure 1 is a schematic diagram of an active reactor power regulation system based on the main heat exchanger system proposed by the present invention;

[0047] Figure 2 is a schematic diagram of the coolant flow distribution principle of an active reactor power regulation method based on the main heat exchanger system proposed by the present invention;

[0048] Figure 3 is a flowchart of the accurate calculation program for the heat exchanger flow rate of an active reactor power regulation method based on the main heat exchanger system proposed by the present invention. Detailed Embodiments

[0049] The following combines the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. However, it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0050] Embodiment 1

[0051] As Figures 1-3 shown, the present invention provides an active reactor power regulation method based on the main heat exchanger system, including the following steps:

[0052] Step 1: According to the required core output power of the nuclear reactor, match and calculate the coolant flow rate and coolant temperature after passing through the core of the nuclear reactor.

[0053] Step 2: According to the coolant flow rate and coolant temperature after passing through the core of the nuclear reactor, pre-distribute the heat transfer power of each heat exchanger connected to the output end of the core of the nuclear reactor.

[0054] In the main heat exchanger module of the primary loop of a nuclear reactor, usually four heat exchangers are arranged. The coolant enters the reactor core under the action of the main pump. After absorbing the heat of the reactor core, the high-temperature coolant flows into each heat exchanger connected to the output end of the reactor core of the nuclear reactor. In each heat exchanger, heat is exchanged with the cold fluid of the secondary loop system, so that the heat of the reactor core can be converted into electric energy in the secondary loop, and the temperature of the primary loop coolant is reduced to the value required at the reactor core inlet.

[0055] Step 3: According to the coolant temperature flowing into each heat exchanger and the heat transfer power of each heat exchanger, calculate the flow rate of the coolant required for each heat exchanger to obtain the flow rate setting value and the coolant outlet temperature setting value of each heat exchanger, including the following steps:

[0056] Step 3.1: Preset the structural parameters of each heat exchanger;

[0057] Step 3.2: Presume the coolant flow rate of each heat exchanger in advance;

[0058] Step 3.3: According to the coolant temperature flowing into each heat exchanger, call the physical property functions and heat transfer correlation formulas of the coolant fluids on both sides of each heat exchanger, and calculate the coolant outlet temperature T2 of each heat exchanger according to the heat balance equation;

[0059] Step 3.4: When the absolute value of the difference between the coolant outlet temperature T2 of each heat exchanger and the coolant inlet temperature T1 of the reactor core of the nuclear reactor is less than a certain value, take the coolant flow rate of each heat exchanger presumed in advance as the flow rate setting value of the coolant of each heat exchanger, and take the coolant outlet temperature T2 of each heat exchanger as the coolant outlet temperature setting value of each heat exchanger.

[0060] If the coolant flow rate of each heat exchanger pre-allocated is inaccurate, re-presume the coolant flow rate of each heat exchanger, and repeat the above steps to find the accurate coolant flow rate data of the heat exchanger through iteration.

[0061] Step 4: Distribute the coolant flowing out of the reactor core of the nuclear reactor to each heat exchanger.

[0062] Step 5: Monitor the flow rate of each heat exchanger after operation, make the flow rate of the coolant flowing into each heat exchanger equal to the flow rate setting value of the heat exchanger, and ensure that the actual coolant outlet temperature of each heat exchanger reaches the coolant outlet temperature setting value of the heat exchanger by fine-tuning the flow rate of each heat exchanger after operation.

[0063] The coolant flowing out of the reactor core of the nuclear reactor is accurately distributed so that each heat exchanger in the main heat exchanger module obtains a coolant with a specific mass flow rate, and the flow meter at the inlet of the heat exchanger is used to monitor whether the flow rate of the heat exchanger reaches the flow rate setting value of the heat exchanger.

[0064] After all heat exchangers are operating stably, monitor the temperature of the coolant at the outlet of the heat exchanger. Compare the actual coolant outlet temperature of each heat exchanger with the set value of the coolant outlet temperature of the heat exchanger. If the actual coolant outlet temperature of each heat exchanger does not match the set value of the coolant outlet temperature of the heat exchanger, then fine-tune the coolant flow rate at the inlet of the heat exchanger through a feedback signal so that the actual coolant outlet temperature of each heat exchanger reaches the set value of the coolant outlet temperature of the heat exchanger.

[0065] Step 6: Determine the actual coolant flow rate passing through the core of the nuclear reactor based on the coolant flow rate at the inlet of each heat exchanger after fine-tuning, and achieve the regulation of the core output power of the nuclear reactor.

[0066] When the entire primary heat exchanger module is operating stably, the coolant flow rate and the coolant inlet temperature of the core of the nuclear reactor required can be obtained, that is, the core output power of the nuclear reactor required, and thus the active regulation of the power level of the nuclear reactor is completed.

[0067] Embodiment 2

[0068] As Figures 1-3 shown, the present invention provides an active regulation method for the power of a nuclear reactor based on a primary heat exchanger system, which further includes calculating the actual coolant flow rate of each heat exchanger according to the relationship between the heat transfer equation and the heat balance equation, and setting the minimum flow rate of the fluid in the heat exchanger;

[0069] The method for calculating the actual coolant flow rate of the heat exchanger according to the relationship between the heat transfer equation and the heat balance equation is:

[0070] Let:

[0071]

[0072] where k is the total heat transfer coefficient of the heat exchanger, which includes the heat transfer coefficient of the cold fluid surface, the heat transfer coefficient of the hot fluid surface, and the heat conduction of the heat exchanger tube wall;

[0073] Taking the circular tube heat exchanger tube as an example, k is calculated by the following formula:

[0074]

[0075] where hi and ho are the surface heat transfer coefficients inside and outside the heat exchanger tube respectively;

[0076] do and di are the outer diameter and inner diameter of the heat exchanger tube respectively;

[0077] r1 and r2 are the fouling heat resistances inside and outside the heat exchanger tube respectively; λ is the fluid thermal conductivity

[0078] Among them, the convective heat transfer coefficient on the fluid surface is:

[0079]

[0080] Among them, h is the convective heat transfer coefficient on the fluid surface; λ is the thermal conductivity of the fluid; l is the characteristic length;

[0081] Nu is the Nusselt number, which is obtained from the heat transfer correlation;

[0082] A is the total heat transfer area inside the heat exchanger, which can be obtained from the type and geometric parameters of the heat exchanger;

[0083] Δt m is the logarithmic mean temperature difference. For a counter-flow heat exchanger, the logarithmic mean temperature difference is:

[0084]

[0085] Among them, Δt max is the maximum temperature difference between the hot and cold fluids at both ends of the heat exchanger; Δt min is the minimum temperature difference between the hot and cold fluids at both ends of the heat exchanger

[0086] C p is the specific heat capacity at constant pressure of the fluid, which is related to the temperature and pressure of the fluid;

[0087] Δt is the temperature difference between the cold and hot fluids;

[0088] According to the five known parameters in formula (1), the actual coolant flow rate of the heat exchanger is obtained

[0089] According to the actual coolant flow rate of the fluid inside the heat exchanger calculated, the actual flow velocity of the fluid inside the heat exchanger is determined. When the actual flow velocity of the fluid inside the heat exchanger is less than the minimum flow velocity set for the heat exchanger, any one of the heat exchangers is shut down, and the actual coolant flow rates of the remaining heat exchangers are recalculated.

[0090] Example 3

[0091] As Figures 1-3 shown, the present invention provides an active control method for the power of a nuclear reactor based on a main heat exchanger system. When it is necessary to change the core output power of the nuclear reactor, the coolant flowing out from the core of the nuclear reactor can be redistributed according to the changed core output power of the nuclear reactor, so that the mass flow rate of the coolant flowing into each heat exchanger is gradually changed, the total power of each heat exchanger is gradually changed, and it is step by step coupled with the change of the core output power of the nuclear reactor, realizing continuous and stable adjustment of the core output power of the nuclear reactor.

[0092] Example 4

[0093] AsFigures 1-3 As shown in Figures 1-3 , the present invention provides a method for actively regulating the power of a nuclear reactor based on a main heat exchanger system, which includes feedback - regulating the flow rate of the coolant flowing into each heat exchanger according to the actual coolant outlet temperature of each heat exchanger, and achieving the dynamic stability of the main heat exchanger module by regulating the flow rate of the coolant in each heat exchanger.

[0094] Example 5

[0095] As Figures 1-3 As shown in Figures 1-3 , the present invention provides an active nuclear reactor power regulation system based on a reactor main heat exchanger system, including:

[0096] A main heat exchanger module, which is composed of multiple heat exchangers and is used to pre - distribute the heat exchange power of each heat exchanger connected to the output end of the core of the nuclear reactor according to the coolant flow rate and coolant temperature after passing through the core of the nuclear reactor.

[0097] A data acquisition module, which is used to acquire the actual data during the operation of the nuclear reactor, including the coolant inlet temperature of the core of the nuclear reactor, the coolant outlet temperature of the core of the nuclear reactor, the coolant inlet temperature of each heat exchanger in the main heat exchanger module, the coolant outlet temperature of each heat exchanger in the main heat exchanger module, and the coolant flow rate of each heat exchanger in the main heat exchanger module. When the data acquisition module conducts data acquisition, high - precision thermocouples and pressure sensors are installed at the inlet and outlet of the core of the nuclear reactor and at the inlet and outlet of each heat exchanger in the main heat exchanger module to measure the temperature and pressure data of the coolant at the inlet and outlet of the core and the inlet and outlet of the heat exchanger. The data is first transmitted in the form of an electrical signal to the data acquisition system, and after being processed by the data acquisition system, the electrical signal is converted into actual temperature and pressure data, which is transmitted to the data calculation and regulation module. At the same time, the temperature and pressure data are also displayed on the control cabinet for the convenience of the staff to monitor in real time.

[0098] A data calculation and regulation module, which is communicatively connected to the data acquisition module. The data acquisition module sends the actual data acquired during the operation of the nuclear reactor to the data calculation and regulation module. The data calculation and regulation module calculates the required coolant flow rate for each heat exchanger based on the coolant temperature flowing into each heat exchanger and the heat exchange power of each heat exchanger, and obtains the flow rate set value and the coolant outlet temperature set value for each heat exchanger.

[0099] The input parameters of the heat exchanger calculation module include the heat exchange power of each heat exchanger and the coolant inlet temperature of the heat exchanger, and the output parameters include the coolant mass flow rate of the heat exchanger. Among them, the various structural parameters of the heat exchanger are pre - built into the heat exchanger calculation module, which can be changed according to the different structures of the heat exchanger, and information such as the heat exchange area of the heat exchanger can be calculated through the various structural parameters of the heat exchanger.

[0100] The data calculation and regulation module first takes the temperature data of the coolant at the inlet of the heat exchanger as input parameters and inputs them into the Figure 3 calculation program as shown, and the actual coolant flow rate of each heat exchanger is calculated by the calculation program through the aforementioned calculation steps. Then, the data calculation and regulation module processes the data and transfers it to the flow distribution module. The flow distribution module precisely regulates the coolant flow rate in each heat exchanger and optimizes the flow distribution of the core coolant of the nuclear reactor according to the actual measurement data.

[0101] After the coolant flow rate is adjusted according to the value calculated by the data calculation and regulation module, the flow rate is feedback-regulated according to the actual coolant flow rate measured by the flow meter at the outlet of each heat exchanger. The feedback signal is transmitted to the feedback signal receiver, processed by the receiver and then transmitted to the heat exchanger calculation module. The heat exchanger calculation module calculates the actual heat transfer power according to the measured coolant flow rate, and further regulates the flow rate according to the actual heat transfer power, improving the power regulation accuracy of the entire heat exchanger system.

[0102] The flow distribution module is used to distribute the coolant flowing out from the core of the nuclear reactor to each heat exchanger.

[0103] Embodiment 6

[0104] As Figures 1-3 shown, the flow distribution module includes a flow distributor, a storage device and a heating device;

[0105] When the coolant flow rate required by the main heat exchanger module is less than the coolant flow rate flowing out from the core of the nuclear reactor, the flow distributor stores the excess coolant in the storage device;

[0106] When the coolant flow rate required by the main heat exchanger module is greater than the coolant flow rate flowing out from the core of the nuclear reactor, the coolant stored in the storage device is heated to a specific temperature by the heating device and then input into the flow distributor. After that, the flow distributor distributes the flow rate to the main heat exchanger module.

[0107] After receiving the signal sent by the data precise calculation and regulation module, the flow distributor transmits the signal to the valve corresponding to the flow distributor, and each valve corresponds to the flow channel of a heat exchanger.

[0108] The opening degree of the valve is controlled according to the required flow rate to gradually adjust the mass flow rate of the coolant in each heat exchanger. At the same time, the thermal power of the core is adjusted according to the measured temperature of the coolant at the outlet of the heat exchanger to match the power change of the main heat exchanger module and ensure the safe and stable operation of the system.

[0109] In the precise regulation of coolant flow, when the coolant flow required by the main heat exchanger module is less than the original coolant flow, the opening of the bypass valve is controlled so that the excess coolant flows into the storage device. The next time coolant is needed, the power required by the heating device is calculated based on the temperature of the required coolant, and the heating device is automatically turned on to heat the coolant to the specified temperature at a specific power. The required coolant flows out of the storage device and returns to the flow distributor, and finally enters the main heat exchanger module.

[0110] Finally, it should be noted that the above disclosure is only a specific embodiment of the present invention. However, the embodiments of the present invention are not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. An active power regulation method for a nuclear reactor based on a main heat exchanger system, characterized in that, Including the following steps: According to the output power of the core of the required nuclear reactor, match and calculate the coolant flow rate and coolant temperature after passing through the core of the nuclear reactor; in the main heat exchanger module of the primary loop of the nuclear reactor, four heat exchangers are arranged; According to the coolant flow rate and coolant temperature after passing through the core of the nuclear reactor, pre-allocate the heat transfer power of each heat exchanger connected to the output end of the core of the nuclear reactor; According to the coolant temperature flowing into each heat exchanger and the heat transfer power of each heat exchanger, calculate the required coolant flow rate of each heat exchanger to obtain the flow rate setting value and coolant outlet temperature setting value of each heat exchanger; Distribute the coolant flowing out of the core of the nuclear reactor to each heat exchanger; Monitor the flow rate of each heat exchanger after operation, make the flow rate of the coolant flowing into each heat exchanger equal to the flow rate setting value of the heat exchanger, and ensure that the actual coolant outlet temperature of each heat exchanger reaches the coolant outlet temperature setting value of the heat exchanger by fine-tuning the flow rate of each heat exchanger after operation; According to the coolant flow rate at the inlet of each heat exchanger after fine-tuning, determine the actual coolant flow rate passing through the core of the nuclear reactor, and realize the regulation of the output power of the core of the nuclear reactor.

2. The active power regulation method of the nuclear reactor based on the main heat exchanger system according to claim 1, wherein: The calculating the required coolant flow rate of each heat exchanger according to the coolant temperature flowing into each heat exchanger and the heat transfer power of each heat exchanger includes: Pre-set the structural parameters of each heat exchanger; Presume the coolant flow rate of each heat exchanger in advance; According to the coolant temperature flowing into each heat exchanger, call the physical property functions and heat transfer correlation equations of the coolant fluids on both sides of each heat exchanger, and calculate the coolant outlet temperature of each heat exchanger according to the heat balance equation ; When the absolute value of the difference between the coolant outlet temperature of each heat exchanger and the coolant inlet temperature of the core of the nuclear reactor is less than a certain value, the coolant flow rate pre-assumed for each heat exchanger is used as the coolant flow rate setting value for each heat exchanger, and the coolant outlet temperature of each heat exchanger is used as the coolant outlet temperature setting value for each heat exchanger.

3. The active power regulation method of the nuclear reactor based on the main heat exchanger system according to claim 2, wherein: It also includes calculating and checking the actual coolant flow rate of each heat exchanger according to the relationship between the heat transfer equation and the heat balance equation, and setting the minimum flow rate of the fluid in the heat exchanger; Determine the actual flow rate of the fluid in the heat exchanger according to the calculated actual coolant flow rate of the fluid in the heat exchanger. When the actual flow rate of the fluid in the heat exchanger is less than the set minimum flow rate of the heat exchanger, shut down any one of the heat exchangers in the main heat exchanger module, and recalculate the actual coolant flow rate in the remaining heat exchangers in the main heat exchanger module.

4. The method for actively regulating the power of a nuclear reactor based on the main heat exchanger system according to claim 3, characterized in that: The method for calculating and checking the actual coolant flow rate of the heat exchanger according to the relationship between the heat transfer equation and the heat balance equation is: Let: （1） Among them is the overall heat transfer coefficient of the heat exchanger, which includes the heat transfer coefficient of the cold fluid surface, the heat transfer coefficient of the hot fluid surface, and the heat conduction of the heat exchanger tube wall; is the total heat transfer area inside the heat exchanger, which is obtained from the heat exchanger type and geometric parameters; is the logarithmic mean temperature difference. For a counter-flow heat exchanger, the logarithmic mean temperature difference is: （2） wherein is the maximum temperature difference between the hot and cold fluids at both ends of the heat exchanger; is the minimum temperature difference between the hot and cold fluids at both ends of the heat exchanger; is the constant-pressure specific heat capacity of the fluid, which is related to the temperature and pressure of the fluid; is the temperature difference between the cold and hot fluids; Based on the five known parameters in Equation (1), the actual coolant flow rate of the heat exchanger is obtained .

5. The method for actively regulating the power of a nuclear reactor based on the main heat exchanger system according to claim 4, characterized in that: When it is necessary to change the output power of the core of the nuclear reactor, the coolant flowing out of the core of the nuclear reactor can be redistributed according to the changed output power of the core of the nuclear reactor, so that the mass flow rate of the coolant flowing into each heat exchanger changes gradually, the total power of each heat exchanger changes gradually, and is coupled step by step with the change of the output power of the core of the nuclear reactor, realizing continuous and stable regulation of the output power of the core of the nuclear reactor.

6. The active power regulation method of a nuclear reactor based on the main heat exchanger system according to claim 5, wherein: According to the actual coolant outlet temperature of each heat exchanger, perform feedback regulation on the coolant flow rate flowing into each heat exchanger, and realize the dynamic stability of the main heat exchanger module by regulating the coolant flow rate in each heat exchanger.

7. A nuclear reactor power active regulation system based on a reactor main heat exchanger system, characterized in that: Including: A main heat exchanger module, which is composed of multiple heat exchangers and is used to pre-allocate the heat transfer power of each heat exchanger connected to the output end of the core of the nuclear reactor according to the coolant flow rate and coolant temperature after passing through the core of the nuclear reactor; A data acquisition module, which is used to acquire the actual data during the operation of the nuclear reactor, including the coolant inlet temperature of the reactor core of the nuclear reactor, the coolant outlet temperature of the reactor core of the nuclear reactor, the coolant inlet temperature of each heat exchanger in the main heat exchanger module, the coolant outlet temperature of each heat exchanger in the main heat exchanger module, and the coolant flow rate of each heat exchanger in the main heat exchanger module; A data calculation and regulation module, which is communicatively connected to the data acquisition module. The data acquisition module sends the actual data acquired during the operation of the nuclear reactor to the data calculation and regulation module. The data calculation and regulation module calculates the flow rate of the coolant required for each heat exchanger according to the coolant temperature flowing into each heat exchanger and the heat transfer power of each heat exchanger, and obtains the flow rate set value and the coolant outlet temperature set value of each heat exchanger; A flow rate distribution module, which is used to distribute the coolant flowing out of the reactor core of the nuclear reactor to each heat exchanger.

8. The active nuclear reactor power regulation system based on the reactor primary heat exchanger system according to claim 7, characterized in that: The flow rate distribution module includes a flow rate distributor, a storage device, and a heating device; When the coolant flow rate required by the main heat exchanger module is less than the coolant flow rate flowing out of the reactor core of the nuclear reactor, the flow rate distributor stores the excess coolant in the storage device; When the coolant flow rate required by the main heat exchanger module is greater than the coolant flow rate flowing out of the reactor core of the nuclear reactor, the coolant stored in the storage device is heated to a specific temperature by the heating device and then input into the flow rate distributor. After that, the flow rate distributor distributes the flow rate to the main heat exchanger module.

9. The active nuclear reactor power regulation system based on the main heat exchanger system of a reactor, characterized in that: The input parameters of the data calculation and regulation module include the heat transfer power of each heat exchanger and the coolant inlet temperature of the heat exchanger, and the output parameters include the coolant flow rate of the heat exchanger.

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