Non-standard heat system analysis method

Abstract

The application discloses a non-standard thermal system analysis method, which is applied to a secondary loop of a nuclear reactor thermal system and comprises the following steps: obtaining first outlet steam parameters of a once-through steam generator; performing forward calculation according to the first outlet steam parameters until turbine inlet parameters of a steam turbine are obtained, and obtaining a forward result according to forward parameters obtained in the forward calculation process; obtaining an assumed load of a steam turbine generator set; performing reverse trial calculation according to the assumed load until second outlet steam parameters of the once-through steam generator are obtained, and obtaining a reverse result according to reverse parameters obtained in the reverse trial calculation process; comparing the forward result and the reverse result to determine whether a deviation between the forward result and the reverse result is less than a first preset deviation; if yes, it is determined that the forward result and the reverse result are credible, and the forward parameters are taken as parameters of the secondary loop. The method is mutually verified in a forward direction and a reverse direction, an optimal solution is sought under a limited condition, and a calculation result with high precision and high reliability is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear power, in particular to a non-standard thermal system analysis method. BACKGROUND

[0002] With the development and progress of nuclear power technology, it is increasingly required to simplify the structure of the steam generator and improve the heat transfer efficiency of the nuclear power system. The once-through steam generator (OTSG) generates superheated steam through heat transfer pipes, has a compact arrangement of heat transfer pipes, is manufactured in a modular manner, and improves the heat transfer efficiency of the system. It has the technical advantages of small size and good mobility, and can meet the requirements of small-sized reactors under various conditions, compact design, high efficiency power generation, and meeting the needs of multiple users. It is widely used in the research of the new generation of small-sized pressurized water reactors.

[0003] The secondary side of the once-through steam generator actually operates through a series of complex flow and heat transfer processes, including single-phase liquid convection, nucleate boiling, liquid film forced convection evaporation, and liquid deficiency. In particular, the existence of the dryout point and the possible occurrence of two-phase flow instability have a significant impact on the start-stop control of the once-through steam generator. The mechanism of this dynamic instability is that the enthalpy fluctuation caused by the disturbance of the feedwater flow at the inlet of the heat transfer pipe changes the length and pressure drop of the single-phase flow heat transfer region, stimulates the fluctuation of the gas content and void fraction in the two-phase region, and further causes the fluctuation of the flow in the heat transfer channel. The pressure drop and flow fluctuation in the two-phase region are fed back to the single-phase region, thereby generating self-sustaining and decaying dynamic instability, especially during the gas-liquid conversion stage of the secondary loop of the unit. This poses a severe challenge to the start-stop strategy of the steam generator. Therefore, a secondary loop start-stop system and a start-stop reactor strategy are usually developed and designed for the once-through steam generator.

[0004] Before developing and designing the secondary loop start-stop system, it is necessary to conduct calculation analysis and scheme configuration research on the non-standard thermal system for "one reactor one machine", "one reactor two machines", and "one reactor multiple machines". In this process, it is required to gradually determine the main parameters of the secondary loop, including the power of the steam turbine and the generator, the efficiency of the unit, and the like. In particular, under the condition of lacking basic engineering information, an accurate and reliable evaluation method is needed. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a non-standard thermal system analysis method.

[0006] The technical solution adopted by the present application to solve the technical problem is: a non-standard thermal system analysis method is constructed, which is applied to the secondary loop of a nuclear reactor thermal system, and includes the following steps:

[0007] S1, obtaining the first outlet steam parameters of the once-through steam generator, performing forward calculation according to the first outlet steam parameters, until the turbine inlet parameters of the steam turbine are obtained, and obtaining the forward result according to the forward parameters obtained in the forward calculation process;

[0008] S2, obtaining an assumed load of the steam turbine generator unit, performing a reverse trial calculation according to the assumed load until a second outlet steam parameter of the once-through steam generator is obtained, and obtaining a reverse result according to a reverse parameter obtained in the reverse trial calculation;

[0009] S3, comparing the forward result and the reverse result to determine whether a deviation between the forward result and the reverse result is less than a first preset deviation, if yes, determining that the forward result and the reverse result are credible, and taking the forward parameter as a parameter of the secondary circuit.

[0010] Preferably, in the non-standard thermal system analysis method disclosed in the application, the forward calculation according to the first outlet steam parameter until a turbine inlet parameter of the steam turbine comprises:

[0011] obtaining the first outlet steam parameter of the once-through steam generator;

[0012] calculating a valve outlet parameter of a main steam isolation valve according to the first outlet steam parameter;

[0013] calculating the turbine inlet parameter of the steam turbine according to the valve outlet parameter.

[0014] Preferably, in the non-standard thermal system analysis method disclosed in the application, the calculation of the valve outlet parameter of the main steam isolation valve according to the first outlet steam parameter comprises:

[0015] constructing a communication pipe section between the once-through steam generator and the main steam isolation valve, and obtaining a first valve outlet parameter through steady-state balance calculation;

[0016] obtaining a second valve outlet parameter through thermodynamic property calculation based on a preset property method;

[0017] determining whether a deviation value of the first valve outlet parameter and the second valve outlet parameter is less than a second preset deviation, if no, taking an average value of the first valve outlet parameter and the second valve outlet parameter as the valve outlet parameter of the main steam isolation valve.

[0018] Preferably, in the non-standard thermal system analysis method disclosed in the application, the calculation of the turbine inlet parameter of the steam turbine according to the valve outlet parameter comprises:

[0019] calculating a first turbine inlet parameter according to the valve outlet parameter based on an empirical formula;

[0020] Adjust the thermal component parameters until the trial calculation results match the rated operating conditions, then adjust the thermal component parameters to the over-generation operating conditions to obtain the first trial calculation results under the over-generation operating conditions; calculate the second turbine inlet parameters based on the valve outlet parameters and the first trial calculation results.

[0021] Combining design specifications, extreme analysis, and sensitivity analysis, the second trial calculation result of the simulated thermodynamic system is obtained; based on the valve outlet parameters and the second trial calculation result, the third turbine inlet parameters are calculated.

[0022] Determine whether the deviation between the first turbine inlet parameter, the second turbine inlet parameter, and the third turbine inlet parameter is greater than a third preset deviation. If not, take the average value of the first turbine inlet parameter, the second turbine inlet parameter, and the third turbine inlet parameter as the turbine inlet parameter.

[0023] Preferably, in the non-standard thermal system analysis method disclosed in this invention, the step of calculating the first turbine inlet parameters based on the valve outlet parameters using empirical formulas specifically involves:

[0024] The valve outlet parameters are calculated by exponentially multiplying them by 0.8 to obtain the first turbine inlet parameters.

[0025] Preferably, in the non-standard thermal system analysis method disclosed in this invention, the step of performing reverse calculations based on the assumed load until the second outlet steam parameters of the direct-flow steam generator are obtained includes:

[0026] Obtain the load value of the steam turbine generator set, and calculate the rated gas consumption of the steam turbine generator set based on the load value;

[0027] The condensate balance result of the condenser is obtained by calculating the rated gas consumption.

[0028] The thermal balance of the deaerator is calculated based on the condensate balance results.

[0029] The second outlet steam parameters of the DC steam generator are calculated based on the rated gas consumption, the condensate balance result, and the thermal balance result.

[0030] Preferably, in the non-standard thermodynamic system analysis method disclosed in this invention, the following steps are performed before performing step S3:

[0031] Determine whether the deviation between the second outlet steam parameter and the first outlet steam parameter is less than or equal to a preset deviation. If not, determine that the reverse calculation has not converged, and re-assume a new assumed load to obtain a new reverse result.

[0032] Preferably, in the non-standard thermal system analysis method disclosed by the application, the forward result comprises generator output power calculated according to the turbine inlet parameter;

[0033] The reverse result comprises simulated output power calculated according to the assumed load.

[0034] Preferably, in the non-standard thermal system analysis method disclosed by the application, the maximum acceptable deviation of the forward result and the reverse result is 2.77.

[0035] Preferably, in the non-standard thermal system analysis method disclosed by the application, the forward parameter comprises the first outlet steam parameter, the valve outlet parameter and the turbine inlet parameter.

[0036] The reverse parameter comprises the second outlet steam parameter, the assumed load, the rated air consumption, the condensate balance result and the thermal balance.

[0037] By implementing the application, the following beneficial effects are achieved:

[0038] The application discloses a non-standard thermal system analysis method, which is applied to a secondary loop of a nuclear reactor thermal system and comprises the following steps: obtaining a first outlet steam parameter of a once-through steam generator, performing forward calculation according to the first outlet steam parameter until a turbine inlet parameter of a steam turbine is obtained, and calculating a forward result according to forward parameters obtained in the forward calculation process; obtaining an assumed load of a steam turbine generator set, performing reverse trial calculation according to the assumed load until a second outlet steam parameter of the once-through steam generator is obtained, and calculating a reverse result according to reverse parameters obtained in the reverse trial calculation process; comparing the forward result and the reverse result, judging whether a deviation between the forward result and the reverse result is less than a first preset deviation, and if yes, determining that the forward result and the reverse result are credible, and taking the forward parameters as parameters of the secondary loop. The method verifies each other, seeks an optimal solution under limited conditions, and obtains a calculation result with high precision and high reliability. BRIEF DESCRIPTION OF DRAWINGS

[0039] The application will be further described below with reference to the drawings and embodiments. In the drawings:

[0040] Figure 1 FIG. 1 is a flowchart of a non-standard thermal system analysis method in a first embodiment of the application. DETAILED DESCRIPTION

[0041] In order to have a clearer understanding of the technical features, objectives and effects of the application, the specific embodiments of the application will be described in detail with reference to the drawings.

[0042] It should be noted that the flowcharts shown in the drawings are only illustrative, and do not necessarily include all contents and operations / steps, nor are they necessarily executed in the order described. For example, some operations / steps can be further decomposed, and some operations / steps can be combined or partially combined, so the actual execution order can be changed according to the actual situation.

[0043] The block diagrams shown in the drawings are only functional entities, and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0044] Referring to Figure 1 The first embodiment of the present application discloses a non-standard thermal system analysis method, applied to the secondary circuit of a nuclear reactor thermal system, comprising the following steps:

[0045] S1, obtaining the first outlet steam parameters of the once-through steam generator, performing forward calculation according to the first outlet steam parameters until obtaining the turbine inlet parameters of the steam turbine, and obtaining the forward result according to the forward parameters obtained during the forward calculation process; if the forward result is reliable, it can be considered that the forward parameters during the entire forward trial calculation process are reliable. The first outlet steam parameters are obtained according to nuclear power calculation, including the outlet steam pressure, outlet steam temperature and outlet steam flow of the once-through steam generator.

[0046] S2, obtaining the assumed load of the steam turbine generator set, performing reverse trial calculation according to the assumed load until obtaining the second outlet steam parameters of the once-through steam generator, and obtaining the reverse result according to the reverse parameters obtained during the reverse trial calculation process; if the reverse result is reliable, it can be considered that the reverse parameters during the entire reverse trial calculation process are reliable.

[0047] S3, comparing the forward result and the reverse result to determine whether the deviation between the forward result and the reverse result is less than a first preset deviation, if yes, determining that the forward result and the reverse result are reliable, and taking the forward parameters as the parameters of the secondary circuit. In some embodiments, the main parameters of the secondary circuit are the power of the steam turbine and the generator and the unit efficiency.

[0048] The non-standard thermal system analysis method disclosed in this embodiment cleverly uses the principle of thermodynamics by combining forward calculation and reverse trial calculation, and in the absence of complete engineering information, it can give relatively accurate and reliable main parameters of the secondary circuit to assist in decision-making, and provides a reliable evaluation method.

[0049] Further, in the non-standard thermal system analysis method disclosed in the embodiment, in step S1, the forward calculation according to the first outlet steam parameter includes the following steps: S11, obtaining the first outlet steam parameter of the once-through steam generator; S12, calculating the valve outlet parameter of the main steam isolation valve according to the first outlet steam parameter; and S13, calculating the turbine inlet parameter of the steam turbine according to the valve outlet parameter. The first outlet steam parameter is calculated according to the nuclear power and includes the outlet steam pressure, the outlet steam temperature and the outlet steam flow rate of the once-through steam generator; and the valve outlet parameter includes the valve outlet pressure, the valve outlet temperature and the valve outlet flow rate of the main steam isolation valve.

[0050] Further, in the non-standard thermal system analysis method disclosed in the embodiment, the calculation of the valve outlet parameter of the main steam isolation valve according to the first outlet steam parameter in step S12 includes the following steps: S121, constructing the connecting pipe section between the once-through steam generator and the main steam isolation valve, and obtaining the first valve outlet parameter through steady-state balance calculation; S122, obtaining the second valve outlet parameter through thermodynamic property calculation based on a preset property method; and S123, judging whether the deviation value of the first valve outlet parameter and the second valve outlet parameter is less than a second preset deviation, and if not, taking the average value of the first valve outlet parameter and the second valve outlet parameter as the valve outlet parameter of the main steam isolation valve.

[0051] Further, in the non-standard thermal system analysis method disclosed in the embodiment, the construction of the connecting pipe section between the once-through steam generator and the main steam isolation valve in step S121 and the obtaining of the first valve outlet parameter through steady-state balance calculation are specifically as follows: the Flomaster software is used to construct the connecting pipe section between the outlet of the once-through steam generator and the main steam isolation valve, and the outlet parameter of the main steam isolation valve is obtained through steady-state balance calculation. In step S122, the second valve outlet parameter is obtained through thermodynamic property calculation based on a preset property method, specifically as follows: the STEAM-TA steam property method from the ASME 1967 standard is taken as the preset property method, and the Aspen Plus software is used to obtain the second valve outlet parameter through thermodynamic property calculation. In addition, the property method from the NBS / NRC 1984 and IAPWS 95 standards can also be used. In order to increase the accuracy, the calculation can be desensitized by using different property methods, and the result difference is observed. In step S123, if the deviation of the first valve outlet parameter and the second valve outlet parameter obtained by the two methods is less than 1%, it is considered that the calculation deviation is acceptable, and finally the average value of the calculation of both sides is taken as the valve outlet parameter of the main steam isolation valve, otherwise it is necessary to return to check the correctness of the corresponding software model or method.

[0052] Further, in the non-standard thermal system analysis method disclosed in the embodiment, in step S13, the calculation of the turbine inlet parameter based on the valve outlet parameter comprises the following steps: S131, based on an empirical formula, the first turbine inlet parameter is calculated based on the valve outlet parameter; specifically, the corresponding empirical coefficient is selected for calculation according to the Ditws-Boelter formula (i.e. the experimental correlation formula of pipe turbulent heat transfer). Since the turbulent heat transfer coefficient in the pipe is extremely sensitive to the Reynolds number, and the Reynolds number Re is extremely sensitive to the outlet steam flow of the once-through steam generator, it is concluded that the turbine inlet temperature can be calculated according to the 0.8 power of the outlet steam flow of the once-through steam generator. Specifically, the Ditws-Boelter formula is expressed as: Nu=C×Re m ×Pr n Wherein, Nu is the Nusselt number, which represents the heat transfer condition; Re is the Reynolds number, which represents the characteristics of fluid motion; Pr is the Prandtl number, which represents the physical properties of the fluid; C, m and n are empirical coefficients, which depend on heat transfer and fluid properties. In a specific embodiment, the first empirical coefficient C is 0.023, the second empirical coefficient m is 0.8, and the third empirical coefficient n is 0.3.

[0053] S132, adjust the thermal component parameters until the trial results and the rated operating condition are consistent, then adjust the thermal component parameters to the overrated operating condition to obtain the first trial result under the overrated operating condition; based on the valve outlet parameter and the first trial result, the second turbine inlet parameter is calculated; specifically, the actual implementation of this step S132 can use the Relap5 code based on the rated operating condition, and the thermal component parameters are constantly adjusted until the trial results of the Relap5 code completely match the standard rated operating condition. Then change the parameters of the overrated operating condition, and finally obtain the trial results of the overrated operating condition. Wherein, Relap5 is a transient analysis program for light water reactors developed by Idaho National Engineering Laboratory (INEL) for Nuclear Regulatory Commission (NRC), which has become a basic tool for nuclear power plant analysis.

[0054] S133, combined with the design specification, extreme analysis and sensitivity analysis, the second trial result of the simulated thermal system is calculated; according to the valve outlet parameter and the second trial result, the third steam turbine inlet parameter is calculated; further, Aspen Plus is a large general process simulation system for production plant design, steady-state simulation and optimization. Specifically, step S133 is based on Aspen Plus software, combined with design specification, extreme analysis and sensitivity analysis, to calculate the second trial result of the simulated thermal system. In terms of design specification, two design specifications are used, one is to simulate the minimum flow control requirement of the main feed water pump, and the other is to simulate the deaerator temperature control, and the balance flow of the recirculation purification is automatically optimized. In terms of extreme analysis, in the two-loop water entity stage, under the maximum flow of the once-through steam generator, the recirculation backwater flow of the deaerator is the largest; in the two-loop steam stage, the void fraction is 1, and under the maximum flow of the once-through steam generator, the startup boiler heat supplement is the largest. In terms of sensitivity analysis, in the steam production stage, especially when the void fraction exceeds 50%, different recirculation purification backwater flow has different startup boiler heat supplement requirements, so the design sensitivity analysis is performed. Through the above three aspects of design specification, extreme analysis and sensitivity analysis, the third steam turbine inlet parameter is obtained.

[0055] Through steps S131 to S133, three referenceable steam turbine inlet parameters obtained by three different calculation methods are obtained, in order to determine whether the three referenceable steam turbine inlet parameters and the actual steam turbine inlet parameter are consistent, and to determine how to obtain the actual steam turbine inlet parameter from the three referenceable steam turbine inlet parameters, the following steps are further executed: S134, judging whether the deviation value between the first steam turbine inlet parameter, the second steam turbine inlet parameter and the third steam turbine inlet parameter is greater than the third preset deviation, if not, it is determined that the calculation deviation is acceptable, and the average value of the first steam turbine inlet parameter, the second steam turbine inlet parameter and the third steam turbine inlet parameter is taken as the steam turbine inlet parameter. If the deviation value between the first steam turbine inlet parameter, the second steam turbine inlet parameter and the third steam turbine inlet parameter is greater than the third preset deviation, it is determined that the calculation deviation is unacceptable, and it is necessary to return to execute step S131 and check the correctness of the software model or method.

[0056] Further, in order to meet the actual procurement and other needs, in the non-standard thermal system analysis method disclosed in the embodiment, the following steps are further included: S5, when the result obtained by step S134 is that the calculation deviation is acceptable, the steam turbine inlet parameter is fed back to the actual steam turbine manufacturer for further forward evaluation in actual use, so as to obtain key data such as steam turbine power, steam turbine generator set output power and nuclear power plant efficiency.

[0057] Further, in the non-standard thermal system analysis method disclosed in the embodiment, the first steam turbine inlet parameter is calculated based on the valve outlet parameter according to the empirical formula, specifically, the 0.8 power of the valve outlet parameter is calculated to obtain the first steam turbine inlet parameter.

[0058] Further, in the non-standard thermal system analysis method disclosed in the embodiment, in step S2, the second outlet steam parameter of the once-through steam generator is obtained by reverse calculation according to the assumed load, which includes the following steps: S21, obtaining the load value of the steam turbine generator set, and calculating the rated steam consumption of the steam turbine generator set according to the load value; S22, calculating the condensate balance result of the condenser according to the rated steam consumption; S23, calculating the thermal balance result of the deaerator according to the condensate balance result; and S24, calculating the second outlet steam parameter of the once-through steam generator according to the rated steam consumption, the condensate balance result and the thermal balance result. It has been proved in practice that, without considering the differentiated characteristics of the steam turbine, the final error of the reverse calculation is within 10%; and considering the differentiated characteristics of the steam turbine, the calculation error is further reduced to less than 5%.

[0059] The reverse calculation method is to analyze the problem from the perspective of system thermal balance and material balance, and the steam turbine uses a simple isentropic expansion model. In practice, the situation is relatively complex and variable, so the reverse calculation only provides a reference result, and the specific data should be confirmed according to the feedback data of the steam turbine manufacturer. If the reverse calculation is only preliminary calculation, and the characteristics of the steam turbine, i.e., the effective efficiency of the steam turbine generator set and the selected standard value of the last-stage blade back pressure, are not confirmed, the final error is calculated to be within 10%; if the detailed calculation is performed, the differentiated characteristics of the steam turbine are considered, and the error is further reduced to less than 5%. This means that in the pre-project analysis and demonstration stage, the error of the reverse calculation can meet the preliminary evaluation requirements and provide important data support for related technical decisions.

[0060] Further, in order to meet the requirement for precision, in the non-standard thermal system analysis method disclosed in the embodiment, before step S3 is performed, the following step is performed first: S30, judging whether the deviation value between the second outlet steam parameter and the first outlet steam parameter is less than or equal to a preset deviation, if not, it is determined that the reverse calculation has not converged, and a new assumed load is re-assumed to calculate a new reverse result again.

[0061] Further, in the non-standard thermal system analysis method disclosed in the embodiment, the forward result includes the generated power of the generator calculated according to the steam turbine inlet parameter; and the reverse result includes the simulated generated power calculated according to the assumed load.

[0062] Further, in the non-standard thermal system analysis method disclosed in the embodiment, the maximum acceptable deviation of the forward result and the reverse result is 2.77.

[0063] Further, in the non-standard thermal system analysis method disclosed in the embodiment, the forward parameter includes the first outlet steam parameter, the valve outlet parameter and the turbine inlet parameter; and the reverse parameter includes the second outlet steam parameter, the assumed load, the rated air consumption, the condensate balance result and the thermal balance.

[0064] Further, in some embodiments, the back pressure information of the steam turbine and the effective efficiency of the steam turbine are provided by at least two steam turbine manufacturers at the beginning of the reverse trial calculation, then the step of assuming the generator is responsible is entered, and finally the power generation is obtained according to the reverse parameter calculation in the reverse trial calculation process; the turbine inlet parameter of the steam turbine obtained in the forward calculation process is fed back to the at least two steam turbine manufacturers, and the power generation is obtained by the steam turbine manufacturers through the forward calculation; the two power generation results obtained by the forward calculation and the reverse trial calculation are compared, and it can be known whether the model or method has a problem, if the deviation is less than a specified value, the forward result and the reverse result are acceptable, and it also indicates that the calculation model and method are available. Then the power generations of the steam turbines provided by the at least two manufacturers are compared, and selection, etc. is performed. If the results of the two parties are very different, the trial calculation is continued until the acceptance requirement is met.

[0065] By implementing the present application, the following beneficial effects are obtained:

[0066] 1) A "trial calculation method" is proposed, which allows not to confirm the characteristics of the steam turbine, is not sensitive to the data, i.e. the selection of the standard value of the effective efficiency of the steam turbine generator set and the back pressure of the last stage blade, and the final error is within 10%; and allows to consider the differentiated characteristics of the steam turbine, and the calculation error is further reduced;

[0067] 2) In the forward analysis path, two software are used to "back-to-back" calculate the parameters after the main steam isolation valve, a weighted average algorithm is designed, which can effectively guarantee the calculation accuracy; three or more calculation methods are used to confirm the turbine inlet parameter of the steam turbine, and a plurality of optimization processing methods are considered, which further guarantee the calculation accuracy; different steam turbine suppliers are allowed to carry out differentiated analysis, and the analysis results are compared and corrected through the reverse path;

[0068] 3) In the reverse analysis path, an innovative method is proposed, which allows to assume the load of the steam turbine unit, reversely calculates the rated air consumption of the steam turbine generator set, the condensate under the thermal balance of the condenser, and the thermal balance of the deaerator, and finally obtains the reverse value of the outlet parameter of the once-through steam generator; a method and a convergence criterion are proposed by comparing the reverse value and the given value, which are iterated repeatedly until the calculation converges;

[0069] 4) Put forward the method of positive and negative combination, mutual support and restraint, seek the optimal solution under the limited condition, without considering the detailed conventional island configuration information, can obtain high precision and high reliability of the calculation results; and has strong compatibility and adaptability, meet "a pile of a machine", "a pile of two machines", "a pile of multi-machine" non-standard heat system for calculation and analysis and scheme configuration research.

[0070] It can be understood that the above embodiments only express the preferred embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application; It should be pointed out that for ordinary skilled in the art, the above-mentioned embodiments or technical features can be freely combined without departing from the concept of the present application, and several modifications and improvements can be made, which belong to the protection scope of the present application, that is, the embodiments described in "in some embodiments" can be freely combined with any embodiment above and below; therefore, any equivalent transformation and modification within the scope of the claims of the present application shall belong to the scope of the claims of the present application.

Claims

1. A method for analyzing non-standard thermodynamic systems, characterized in that, The secondary loop used in a nuclear reactor thermal system includes the following steps: S1. Obtain the first outlet steam parameters of the DC steam generator, perform forward calculation based on the first outlet steam parameters until the turbine inlet parameters of the steam turbine are obtained, and calculate the forward result based on the forward parameters obtained during the forward calculation process. S2. Obtain the assumed load of the steam turbine generator set, perform reverse calculation based on the assumed load until the second outlet steam parameters of the DC steam generator are obtained, and calculate the reverse result based on the reverse parameters obtained during the reverse calculation process. S3. Compare the positive result and the negative result, and determine whether the deviation between the positive result and the negative result is less than a first preset deviation. If so, determine that the positive result and the negative result are reliable, and use the positive parameter as the parameter of the second loop. in, The step of performing reverse calculations based on the assumed load until the second outlet steam parameters of the direct-flow steam generator are obtained includes: Obtain the load value of the steam turbine generator set, and calculate the rated gas consumption of the steam turbine generator set based on the load value; The condensate balance result of the condenser is obtained by calculating the rated gas consumption. The thermal balance of the deaerator is calculated based on the condensate balance results. The second outlet steam parameters of the DC steam generator are calculated based on the rated gas consumption, the condensate balance result, and the thermal balance result. Before performing step S3, perform the following steps: Determine whether the deviation between the second outlet steam parameter and the first outlet steam parameter is less than or equal to a preset deviation. If not, determine that the reverse calculation has not converged, and re-assume a new assumed load to calculate a new reverse result. The positive result includes the generator output power calculated based on the turbine inlet parameters; The reverse result includes the simulated output power calculated based on the assumed load.

2. The non-standard thermal system analysis method according to claim 1, characterized in that, The step of performing forward calculations based on the first outlet steam parameters until the turbine inlet parameters are obtained includes: Obtain the first outlet steam parameters of the DC steam generator; The valve outlet parameters of the main steam isolation valve are calculated based on the first outlet steam parameters. The turbine inlet parameters are calculated based on the valve outlet parameters.

3. The non-standard thermal system analysis method according to claim 2, characterized in that, The valve outlet parameters of the main steam isolation valve calculated based on the first outlet steam parameters include: Construct a connecting pipe section between the DC steam generator and the main steam isolation valve, and obtain the outlet parameters of the first valve through steady-state balance calculation; Based on a pre-defined physical property method, the outlet parameters of the second valve are obtained through thermodynamic property calculations. Determine whether the deviation between the first valve outlet parameter and the second valve outlet parameter is less than a second preset deviation. If not, take the average value of the first valve outlet parameter and the second valve outlet parameter as the valve outlet parameter of the main steam isolation valve.

4. The non-standard thermal system analysis method according to claim 2, characterized in that, The calculation of the turbine inlet parameters based on the valve outlet parameters includes: Based on empirical formulas, the inlet parameters of the first steam turbine are calculated according to the valve outlet parameters. Adjust the thermal component parameters until the trial calculation results match the rated operating conditions, then adjust the thermal component parameters to the over-generation operating conditions to obtain the first trial calculation results under the over-generation operating conditions; calculate the second turbine inlet parameters based on the valve outlet parameters and the first trial calculation results. Combining design specifications, extreme analysis, and sensitivity analysis, the second trial calculation result of the simulated thermodynamic system is obtained; based on the valve outlet parameters and the second trial calculation result, the third turbine inlet parameters are calculated. Determine whether the deviation between the first turbine inlet parameter, the second turbine inlet parameter, and the third turbine inlet parameter is greater than a third preset deviation. If not, take the average value of the first turbine inlet parameter, the second turbine inlet parameter, and the third turbine inlet parameter as the turbine inlet parameter.

5. The method for analyzing non-standard thermal systems according to claim 4, characterized in that, The calculation of the first turbine inlet parameters based on the valve outlet parameters using empirical formulas is as follows: The valve outlet parameters are calculated by exponentially multiplying them by 0.8 to obtain the first turbine inlet parameters.

6. The method for analyzing non-standard thermodynamic systems according to any one of claims 1 to 5, characterized in that, The maximum acceptable deviation between the positive and negative results is 2.

77.

7. The method for analyzing non-standard thermal systems according to claim 2, characterized in that, The positive parameters include the first outlet steam parameters, the valve outlet parameters, and the turbine inlet parameters; The reverse parameters include the second outlet steam parameters, the assumed load, the rated gas consumption, the condensate balance result, and the thermal balance.

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