Non-standard thermodynamic system analysis method

Abstract

The invention discloses a non-standard thermodynamic system analysis method, which is applied to a secondary loop of a nuclear reactor thermodynamic system, and comprises the following steps: acquiring a first outlet steam parameter of a straight-flow steam generator, and performing forward calculation according to the first outlet steam parameter until a steam turbine inlet parameter is obtained, a forward result is obtained through calculation according to forward parameters obtained in the forward calculation process; the assumed load of the steam generator unit is obtained, reverse trial calculation is conducted according to the assumed load until a second outlet steam parameter of the straight-flow type steam generator is obtained, and a reverse result is obtained through calculation according to a reverse parameter obtained in the reverse trial calculation process; and comparing the forward result with the reverse result, judging whether the deviation between the forward result and the reverse result is smaller than a first preset deviation, if so, judging that the forward result and the reverse result are credible, and taking the forward parameter as the parameter of the secondary loop. According to the method, positive and negative mutual evidence is achieved, an optimal solution is sought under limited conditions, and a high-precision and high-reliability calculation result is obtained.

Description

Technical Field

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

[0002] With the development and progress of nuclear power technology, the requirements for simplifying the steam generator structure and improving the heat transfer efficiency of nuclear power systems are becoming stronger and stronger. The heat transfer tubes of the once-through steam generator (OTSG) generate superheated steam, the heat transfer tubes are compactly arranged, modularly manufactured, and improve the thermal efficiency of the system. It has the technical advantages of small size and good mobility. It can adapt to the requirements of small reactors for compact design, high-efficiency power generation, and meet the needs of multiple users under various conditions. It is widely used in the research of the new generation of small pressurized water reactor technology.

[0003] The actual operation of the secondary side of the once-through steam generator goes through a series of complex flow and heat exchange processes such as the single-phase liquid convection zone, nucleate boiling zone, liquid film forced convection evaporation zone and liquid-deficient zone. In particular, the existence of the evaporation point and the possible occurrence of two-phase flow instability have a great impact on the start-stop control of the once-through steam generator. The mechanism of this dynamic instability is that the disturbance of the feed water flow at the inlet of the heat transfer tube causes the fluctuation of the enthalpy value, which causes the change of the length and pressure drop of the single-phase flow heat transfer area, stimulates the fluctuation of the gas content and cavitation fraction in the two-phase area, and then causes the fluctuation of the heat transfer channel flow. The pressure drop and flow fluctuations in the two-phase area are also fed back to the single-phase area, thereby generating self-sustaining and attenuated dynamic instability, especially in the gas-liquid conversion stage of the unit's secondary circuit, which brings severe tests to the start-stop strategy of the steam generator. Therefore, the secondary circuit startup system and start-stop stack strategy are usually developed and designed for once-through steam generators.

[0004] Before developing and designing the secondary-loop start-stop reactor system, it is necessary to conduct calculation analysis and solution configuration research on the non-standard thermal systems of "one reactor and one unit", "two reactors and two units", and "multiple reactors". In this process, it is required to gradually clarify the main parameters of the secondary loop, including turbine and generator power, unit efficiency, etc., especially in the absence of basic engineering information, an accurate and reliable evaluation method is needed. Summary of the invention

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

[0006] The technical solution adopted by the present invention to solve the technical problem is: construct a non-standard thermal system analysis method, which is applied to the secondary circuit of the thermal system of a nuclear reactor, comprising the following steps:

[0007] S1. 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 is obtained, and obtaining a forward result according to the forward parameter obtained in the forward calculation process;

[0008] S2, obtaining an assumed load of the steam generator set, performing a reverse calculation based on the assumed load until a second outlet steam parameter of the once-through steam generator is obtained, and calculating a reverse result based on the reverse parameters obtained in the reverse calculation process;

[0009] S3. Compare 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 so, determine that the forward result and the reverse result are credible, and use the forward parameter as a parameter of the second loop.

[0010] Preferably, in the non-standard thermal system analysis method disclosed in the present invention, the forward calculation is performed according to the first outlet steam parameter until the turbine inlet parameter is obtained, comprising:

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

[0012] Calculate and obtain valve outlet parameters of the main steam isolation valve according to the first outlet steam parameters;

[0013] The turbine inlet parameters of the steam turbine are calculated based on the valve outlet parameters.

[0014] Preferably, in the non-standard thermal system analysis method disclosed in the present invention, the valve outlet parameter of the main steam isolation valve is calculated according to the first outlet steam parameter, including:

[0015] Constructing a connecting pipe section from the once-through steam generator to the main steam isolation valve, and obtaining the first valve outlet parameters through steady-state equilibrium calculation;

[0016] Based on the preset physical property method, the second valve outlet parameters are obtained by thermodynamic property calculation;

[0017] Determine whether the deviation value of 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.

[0018] Preferably, in the non-standard thermal system analysis method disclosed in the present invention, the step of calculating the turbine inlet parameters of the steam turbine according to the valve outlet parameters comprises:

[0019] Based on the empirical formula, the first turbine inlet parameter is calculated according to the valve outlet parameter;

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

[0021] In combination with design regulations, extreme analysis and sensitivity analysis, a second trial calculation result of the simulated thermal system is calculated; based on the valve outlet parameter and the second trial calculation result, a third steam turbine inlet parameter is calculated;

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

[0023] Preferably, in the non-standard thermal system analysis method disclosed in the present invention, the first turbine inlet parameter is calculated based on the empirical formula according to the valve outlet parameter as follows:

[0024] The valve outlet parameter is calculated and exponentially raised to the power of 0.8 to obtain the first turbine inlet parameter.

[0025] Preferably, in the non-standard thermal system analysis method disclosed in the present invention, performing reverse calculation according to the assumed load until obtaining the second outlet steam parameter of the once-through steam generator includes:

[0026] Obtaining a load value of the steam generator set, and calculating the rated gas consumption of the steam generator set according to the load value;

[0027] Calculate the condensate balance result of the condenser according to the rated gas consumption;

[0028] Calculate the thermodynamic balance result of the deaerator according to the condensate balance result;

[0029] The second outlet steam parameter of the once-through steam generator is obtained by calculation according to the rated gas consumption, the condensate balance result and the thermodynamic balance result.

[0030] Preferably, in the non-standard thermal system analysis method disclosed in the present invention, before executing step S3, the following steps are first performed:

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

[0032] Preferably, in the non-standard thermal system analysis method disclosed in the present invention, the forward result includes the generator output power calculated based on the turbine inlet parameters;

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

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

[0035] Preferably, in the non-standard thermal system analysis method disclosed in the present invention, the forward parameters include the first outlet steam parameter, the valve outlet parameter and the turbine inlet parameter;

[0036] The reverse parameters include the second outlet steam parameter, the assumed load, the rated gas consumption, the condensate balance result and the thermodynamic balance.

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

[0038] The present invention discloses a non-standard thermal system analysis method, which is applied to the secondary circuit of the thermal system of a nuclear reactor, including: obtaining the first outlet steam parameter of a once-through steam generator, performing forward calculation according to the first outlet steam parameter until the turbine inlet parameter is obtained, and obtaining the forward result according to the forward parameter obtained in the forward calculation process; obtaining the assumed load of the steam generator set, performing reverse calculation according to the assumed load until the second outlet steam parameter of the once-through steam generator is obtained, and obtaining the reverse result according to the reverse parameter obtained in the reverse calculation process; comparing the forward result and the reverse result, judging whether the deviation between the forward result and the reverse result is less than the first preset deviation, if so, judging that the forward result and the reverse result are credible, and taking the forward parameter as the parameter of the secondary circuit. The method positively and negatively corroborates each other, seeks the optimal solution under restricted conditions, and obtains the calculation result with high precision and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0040] Figure 1 It is a flow chart of a non-standard thermal system analysis method in the first embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

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

[0043] The block diagrams shown in the accompanying 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 networks and / or processor devices and / or microcontroller devices.

[0044] See also Figure 1 The first embodiment of the present invention discloses a non-standard thermal system analysis method, which is applied to the secondary circuit of a nuclear reactor thermal system, and includes the following steps:

[0045] S1. Obtain the first outlet steam parameter of the once-through steam generator, perform forward calculation according to the first outlet steam parameter, until the turbine inlet parameter is obtained, and obtain the forward result according to the forward parameter obtained in the forward calculation process; if the forward result is credible, it can be considered that the forward parameters in the whole process of executing the forward trial calculation are credible. The first outlet steam parameter is obtained according to the nuclear power calculation, including the outlet steam pressure, outlet steam temperature and outlet steam flow rate of the once-through steam generator.

[0046] S2. Obtain an assumed load of the steam generator set, perform a reverse calculation based on the assumed load until the second outlet steam parameter of the once-through steam generator is obtained, and calculate a reverse result based on the reverse parameters obtained in the reverse calculation process; if the reverse result is credible, it can be considered that the reverse parameters in the entire reverse calculation process are credible.

[0047] S3, comparing the forward result and the reverse result, determining whether the deviation between the forward result and the reverse result is less than a first preset deviation, and if so, determining that the forward result and the reverse result are credible, and using the forward parameter as a parameter of the secondary loop. In some embodiments, the main parameters of the secondary loop are the steam turbine, generator power and unit efficiency.

[0048] The non-standard thermal system analysis method disclosed in this embodiment cleverly utilizes the principles of thermodynamics by combining forward calculation and reverse calculation. In the absence of complete engineering information, it can provide relatively accurate and reliable secondary circuit main parameters to assist in decision-making, thus providing a trustworthy evaluation method.

[0049] Further, in the non-standard thermal system analysis method disclosed in the present embodiment, in step S1, the forward calculation is performed according to the first outlet steam parameter until the turbine inlet parameter is obtained, which includes the following steps: S11, obtaining the first outlet steam parameter of the once-through steam generator;

[0050] S12. Calculate the valve outlet parameters of the main steam isolation valve according to the first outlet steam parameters; S13. Calculate the turbine inlet parameters of the steam turbine according to the valve outlet parameters. The first outlet steam parameters are calculated according to the nuclear power, including the outlet steam pressure, outlet steam temperature and outlet steam flow of the once-through steam generator; the valve outlet parameters include the valve outlet pressure, valve outlet temperature and valve outlet flow of the main steam isolation valve.

[0051] Further, in the non-standard thermal system analysis method disclosed in the present embodiment, the method of calculating 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 a connecting pipe section from the direct-flow steam generator to the main steam isolation valve, and obtaining the first valve outlet parameter through steady-state equilibrium calculation; S122. Based on a preset physical property method, obtaining the second valve outlet parameter through thermodynamic property calculation; S123. Determine whether the deviation value between the first valve outlet parameter and the second valve outlet parameter is less than a second preset deviation; 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.

[0052] Further, in the non-standard thermal system analysis method disclosed in the present embodiment, the construction of the connecting pipe section between the direct-flow steam generator and the main steam isolation valve in step S121, and obtaining the first valve outlet parameters through steady-state equilibrium calculation are specifically as follows: the connecting pipe section between the direct-flow steam generator outlet and the main steam isolation valve is constructed using Flomaster software, and the outlet parameters of the main steam isolation valve are obtained through steady-state equilibrium calculation. In step S122, based on the preset physical property method, the second valve outlet parameters are obtained through thermodynamic property calculation, specifically as follows: the STEAM-TA steam physical property method derived from the ASME 1967 standard is used as the preset physical property method, and the second valve outlet parameters are obtained through thermodynamic property calculation using Aspen Plus software. In addition, physical property methods derived from NBS / NRC 1984 and IAPWS 95 standards can also be used. In order to increase the accuracy, different physical property methods are used to calculate the desensitization analysis of the physical property method to view the difference in results. In step S123, if the deviation between the first valve outlet parameter and the second valve outlet parameter calculated by the two methods is less than 1%, the calculation deviation is considered acceptable, and finally the calculated mean of both 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.

[0053] Further, in the non-standard thermal system analysis method disclosed in the present embodiment, in step S13, the calculation of the turbine inlet parameters of the steam turbine according to the valve outlet parameters includes the following steps: S131. Based on the empirical formula, the first turbine inlet parameters are calculated according to the valve outlet parameters; specifically, according to the Ditws-Boelter formula (i.e., the experimental correlation formula of turbulent heat transfer in the tube), the corresponding empirical coefficient is selected for calculation. Since the turbulent heat transfer coefficient in the tube is extremely sensitive to the Reynolds number, and the Reynolds number Re is extremely sensitive to the change in the outlet steam flow rate of the direct current steam generator, it is concluded that the turbine inlet temperature can be calculated according to the 0.8 power of the outlet steam flow rate of the direct current steam generator. Specifically, the Ditws-Boelter formula is expressed as: Nu=C×Re m ×Pr n , where Nu is the Nusselt number, which indicates the heat transfer; Re is the Reynolds number, which indicates the characteristics of fluid motion; Pr is the Prandtl number, which indicates the physical properties of the fluid; C, m and n are all empirical coefficients, which depend on the 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.

[0054] S132, adjust the thermal construction parameters until the trial calculation results match the rated conditions, adjust the thermal component parameters to the over-generation conditions to obtain the first trial calculation results under the over-generation conditions; calculate and obtain the second turbine inlet parameters based on the valve outlet parameters and the first trial calculation results; specifically, the actual implementation of step S132 can use the Relap5 code based on the rated conditions, and continuously try to adjust the thermal component parameters until the trial calculation results of the Relap5 code are completely consistent with the standard rated conditions. Then change the parameters of the over-generation conditions, and finally obtain the trial calculation results of the over-generation conditions. Among them, Relap5 is a light water reactor transient analysis program developed by the Idaho National Engineering Laboratory (INEL) for the Nuclear Regulatory Commission (NRC), and has now become a basic tool for nuclear power plant analysis.

[0055] S133, combining design regulations, extreme analysis and sensitivity analysis, calculate and obtain the second trial calculation result of the simulated thermal system; according to the valve outlet parameters and the second trial calculation result, calculate and obtain the third steam turbine inlet parameters; further, Aspen Plus is a large-scale general process simulation system for production equipment design, steady-state simulation and optimization. Specifically, step S133 is based on Aspen Plus software, combined with design regulations, extreme analysis and sensitivity analysis, to calculate and obtain the second trial calculation result of the simulated thermal system. In terms of design regulations, two design regulations are used, one is to simulate the minimum flow control requirements of the main feed water pump, automatically optimize the value of the recirculation flow, and the other is to simulate the temperature control of the deaerator, and automatically optimize the balance flow of the reflux purification. In terms of extreme analysis, in the second-loop water entity stage, at the maximum flow of the once-through steam generator, the return water flow of the deaerator recirculation is the largest; in the second-loop steam stage, the cavitation share is 1, and at the maximum flow of the once-through steam generator, the start-up boiler heat supplement is the largest. In terms of sensitivity analysis, during the steam production stage, especially when the cavitation share exceeds 50%, different recirculation purified return water flows have different requirements for start-up boiler heat supplement, so sensitivity analysis is designed here. After comprehensive analysis and calculation of the above-mentioned design regulations, extreme analysis and sensitivity analysis, the inlet parameters of the third steam turbine are obtained.

[0056] Through step S131 to step S133, three reference turbine inlet parameters obtained by three different calculation methods are obtained. In order to determine whether the three reference turbine inlet parameters are consistent with the actual turbine inlet parameters, and to determine how to obtain the actual turbine inlet parameters with the three reference turbine inlet parameters, the following steps are further performed: S134, determine whether the deviation value between the first turbine inlet parameter, the second turbine inlet parameter and the third 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 turbine inlet parameter, the second turbine inlet parameter and the third turbine inlet parameter is taken as the turbine inlet parameter. If the deviation value between the first turbine inlet parameter, the second turbine inlet parameter and the third 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 verify the correctness of the software model or method.

[0057] Furthermore, in order to meet actual procurement needs, the non-standard thermal system analysis method disclosed in this embodiment also includes the following steps: S5. When the result obtained in step S134 is judged to be acceptable for the calculation deviation, the steam turbine inlet parameters are fed back to the actual steam turbine manufacturer for the next step of positive evaluation in practice to obtain key data such as steam turbine power, steam turbine generator set output power and nuclear power plant efficiency.

[0058] Furthermore, in the non-standard thermal system analysis method disclosed in the present embodiment, the method of calculating the first turbine inlet parameter based on the valve outlet parameter based on the empirical formula is specifically as follows: calculating the valve outlet parameter to the power of 0.8 for exponential operation to obtain the first turbine inlet parameter.

[0059] Further, in the non-standard thermal system analysis method disclosed in the present embodiment, in step S2, the reverse calculation according to the assumed load until the second outlet steam parameter of the once-through steam generator is obtained includes the following steps: S21, obtaining the load value of the steam generator set, and calculating the rated gas consumption of the steam generator set according to the load value; S22, calculating the condensate balance result of the condenser according to the rated gas consumption; S23, calculating the thermodynamic balance result of the deaerator according to the condensate balance result; S24, calculating the second outlet steam parameter of the once-through steam generator according to the rated gas consumption, the condensate balance result and the thermodynamic balance result. Practice has shown that without considering the differentiated characteristics of the steam turbine, the final error of the reverse calculation is within 10%; considering the differentiated characteristics of the steam turbine, the calculation error is further reduced to less than 5%.

[0060] The reverse calculation method analyzes the problem from the perspective of the system's thermal balance and logistics balance, and the steam turbine uses a simple isentropic expansion model. In practice, the situation is relatively complex and changeable, so the reverse calculation only provides a reference result, and the specific data should be based on the feedback from the steam turbine manufacturer. If the reverse calculation is only performed for the initial calculation without confirming the characteristics of the steam turbine, that is, the standard value of the effective efficiency of the steam generator unit and the back pressure of the last stage blade, the final error is calculated to be within 10%; if a detailed calculation is performed, the differentiated characteristics of the steam turbine are considered, and the error will be further reduced to less than 5%. This means that in the early analysis and demonstration stage of the project, the error of the reverse calculation can meet the preliminary evaluation requirements and provide important data support for relevant technical decisions.

[0061] Furthermore, in order to meet the requirements for accuracy, in the non-standard thermal system analysis method disclosed in this embodiment, before executing step S3, the following steps are first executed: S30, determining 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, determining that the reverse trial calculation has not converged, and re-assuming a new assumed load, and recalculating to obtain a new reverse result.

[0062] Furthermore, in the non-standard thermal system analysis method disclosed in this embodiment, the forward 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.

[0063] Furthermore, in the non-standard thermal system analysis method disclosed in this embodiment, the maximum acceptable deviation between the forward result and the reverse result is 2.77.

[0064] Furthermore, in the non-standard thermal system analysis method disclosed in this embodiment, the forward parameters include the first outlet steam parameters, the valve outlet parameters and the steam 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.

[0065] Furthermore, in some embodiments, at the beginning of the reverse calculation, at least two steam turbine manufacturers provide steam turbine back pressure information and effective efficiency of the steam turbine, then enter the step of assuming that the generator is responsible, and finally obtain the power generation according to the reverse parameter calculation in the reverse calculation process; the steam turbine inlet parameters obtained in the forward calculation process are fed back to at least two steam turbine manufacturers, and the steam turbine manufacturers obtain the power generation through forward calculation; by comparing the two power generation results obtained by the forward calculation and the reverse calculation, it can be known whether there is a problem with the model or method. If the deviation is less than the specified value, both the forward result and the reverse result are acceptable, which also indicates that the calculation model and method are available. Then compare the power generation of the steam turbines provided by these at least two manufacturers, and select the model, etc. If the results of both parties are very different, continue the calculation until the acceptance requirements are met.

[0066] By implementing the present invention, the following beneficial effects are achieved:

[0067] 1) A "trial and error calculation method" is proposed, which allows for non-confirmation of turbine characteristics and is insensitive to its data, i.e., the standard values ​​of effective efficiency of the steam turbine unit and the back pressure of the last stage blade are selected, and the final error is within 10%. It also allows for consideration of the differentiated characteristics of the steam turbine, and the calculation error is further reduced;

[0068] 2) In the forward analysis path, two softwares are used to calculate the parameters after the main steam isolation valve "back to back", and a weighted average algorithm is designed to effectively ensure the calculation accuracy; more than three calculation methods are used to confirm the turbine inlet parameters, and a variety of optimization processing methods are considered to further ensure the calculation accuracy; different turbine suppliers are allowed to carry out differentiated analysis, and the analysis results are compared and corrected through the reverse path;

[0069] 3) In the reverse analysis path, an innovative method is proposed to allow the assumption of steam turbine unit load, reverse the rated gas consumption of the steam turbine generator unit, reverse the condensate volume under the heat balance of the condenser, and the heat balance of the deaerator, and finally obtain the reverse value of the outlet parameters of the once-through steam generator; a method and convergence criterion for comparing the reverse value with the given value is proposed, and it is continuously iterated until the calculation converges;

[0070] 4) A combination of positive and negative methods is proposed to support and restrict each other, and to seek the optimal solution under restricted conditions. High-precision and high-reliability calculation results can be obtained without considering detailed conventional island configuration information; and it has strong compatibility and adaptability, meeting the calculation analysis and scheme configuration research of non-standard thermal systems such as "one pile and one machine", "one pile and two machines", and "one pile and multiple machines".

[0071] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, without departing from the concept of the present invention, the above embodiments or technical features can be freely combined, and several deformations and improvements can be made, which all belong to the protection scope of the present invention, that is, the embodiments described in "some embodiments" can be freely combined with any of the above and below embodiments. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A non-standard thermal system analysis method, characterized in that: Applied to the secondary circuit of the thermal system of a nuclear reactor, the method comprises the following steps: S1. 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 is obtained, and obtaining a forward result according to the forward parameter obtained in the forward calculation process; S2, obtaining an assumed load of the steam generator set, performing a reverse calculation based on the assumed load until a second outlet steam parameter of the once-through steam generator is obtained, and calculating a reverse result based on the reverse parameters obtained in the reverse calculation process; S3. Compare 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 so, determine that the forward result and the reverse result are credible, and use the forward parameter as a parameter of the second loop.

2. The non-standard thermal system analysis method according to claim 1, characterized in that: The forward calculation is performed according to the first outlet steam parameter until the turbine inlet parameter is obtained, comprising: Acquire the first outlet steam parameter of the once-through steam generator; Calculate and obtain valve outlet parameters of the main steam isolation valve according to the first outlet steam parameters; The turbine inlet parameters of the steam turbine are calculated based on the valve outlet parameters.

3. The non-standard thermal system analysis method according to claim 2, characterized in that: The method of calculating the valve outlet parameter of the main steam isolation valve according to the first outlet steam parameter includes: Constructing a connecting pipe section from the once-through steam generator to the main steam isolation valve, and obtaining the first valve outlet parameters through steady-state equilibrium calculation; Based on the preset physical property method, the second valve outlet parameters are obtained by thermodynamic property calculation; Determine whether the deviation value of 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 step of calculating the turbine inlet parameters of the steam turbine according to the valve outlet parameters comprises: Based on the empirical formula, the first turbine inlet parameter is calculated according to the valve outlet parameter; Adjust the thermal construction parameters until the trial calculation results match the rated operating conditions, and then adjust the thermal component parameters to the over-generation operating conditions to obtain a first trial calculation result under the over-generation operating conditions; calculate and obtain the second turbine inlet parameters based on the valve outlet parameters and the first trial calculation results; In combination with design regulations, extreme analysis and sensitivity analysis, a second trial calculation result of the simulated thermal system is calculated; based on the valve outlet parameter and the second trial calculation result, a third steam turbine inlet parameter is calculated; Determine whether the deviation value among the first steam turbine inlet parameter, the second steam turbine inlet parameter and the third steam turbine inlet parameter is greater than a third preset deviation; if not, take the average value of the first steam turbine inlet parameter, the second steam turbine inlet parameter and the third steam turbine inlet parameter as the steam turbine inlet parameter.

5. The non-standard thermal system analysis method according to claim 4, characterized in that: The first turbine inlet parameter is calculated based on the empirical formula according to the valve outlet parameter and is specifically: The valve outlet parameter is calculated and exponentially raised to the power of 0.8 to obtain the first turbine inlet parameter.

6. The non-standard thermal system analysis method according to any one of claims 1 to 5, characterized in that: The reverse calculation is performed according to the assumed load until the second outlet steam parameter of the once-through steam generator is obtained, comprising: Obtaining a load value of the steam generator set, and calculating the rated gas consumption of the steam generator set according to the load value; Calculate the condensate balance result of the condenser according to the rated gas consumption; Calculate the thermodynamic balance result of the deaerator according to the condensate balance result; The second outlet steam parameter of the once-through steam generator is obtained by calculation according to the rated gas consumption, the condensate balance result and the thermodynamic balance result.

7. The non-standard thermal system analysis method according to any one of claims 1 to 5, characterized in that: Before executing step S3, the following steps are performed: Determine whether the deviation value between the second outlet steam parameter and the first outlet steam parameter is less than or equal to the preset deviation. If not, determine that the reverse trial calculation has not converged, and re-assume a new assumed load and recalculate to obtain a new reverse result.

8. The non-standard thermal system analysis method according to any one of claims 1 to 5, characterized in that: The forward result includes the generator output power calculated based on the turbine inlet parameters; The reverse result includes a simulated output power calculated according to the assumed load.

9. The non-standard thermal system analysis method according to any one of claims 1 to 5, characterized in that: The maximum acceptable deviation between the forward result and the reverse result is 2.

77.

10. The non-standard thermal system analysis method according to claim 6, characterized in that: The forward parameters include the first outlet steam parameter, the valve outlet parameter and the turbine inlet parameter; The reverse parameters include the second outlet steam parameter, the assumed load, the rated gas consumption, the condensate balance result and the thermodynamic balance.

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