A method and device for peak shaving of a combined heat and power nuclear unit based on secondary loop adjustment

Abstract

This invention belongs to the field of nuclear power unit control technology, and discloses a method and apparatus for peak shaving in a cogeneration nuclear power unit based on secondary loop adjustment. The method includes: collecting the heat balance diagram of the cogeneration nuclear power unit; establishing mass and energy balance equations for each stage of the heaters in the secondary loop of the nuclear power unit, wherein a heat storage tank is installed in the secondary loop; converting the mass and energy balance equations into steam-water distribution equations; obtaining the extraction steam amount for each stage of regeneration in the secondary loop of the nuclear power unit based on the steam-water distribution equations; calculating the minimum and maximum turbine power through the work equations of the secondary loop of the nuclear power unit; defining the electrical load adjustment range of the nuclear power unit as less than or equal to the maximum turbine power and greater than or equal to the minimum turbine power; and performing peak shaving based on the electrical load adjustment range. This invention avoids the safety hazards of traditional nuclear power peak shaving and helps to improve the flexibility and scope of cogeneration nuclear power unit heat and power load adjustment.

Description

Technical Field

[0001] This invention relates to the field of nuclear power unit control technology, and in particular to a peak-shaving method and apparatus for cogeneration nuclear power units based on secondary loop adjustment. Background Technology

[0002] In recent years, my country has proposed the active, safe, and orderly development of nuclear power and the steady and proactive implementation of nuclear heating demonstration projects. Under the premise of ensuring energy security, the country is vigorously implementing renewable energy substitution and accelerating the construction of a clean, low-carbon, safe, and efficient energy system. Nuclear power is ushering in a new round of development opportunities, but also faces challenges.

[0003] In winter, centralized heating is required in northern my country, with coal-fired power plants or boilers being the primary heat source. Nuclear energy, as a clean energy source, is an important "clean" heat source. However, for a long time, nuclear power in my country has primarily focused on electricity production. With the increasing proportion of wind and solar power grid connection, small-capacity, high-energy-consuming coal-fired power plants are gradually being shut down, leading to a growing demand for comprehensive utilization of nuclear energy and auxiliary power generation. Simultaneously addressing the needs of people's livelihoods, such as meeting varying heat load requirements, while simultaneously generating electricity, the economic and environmental benefits are becoming increasingly apparent. Combined heat and power (CHP) nuclear power units utilize steam extracted from the secondary turbine to provide heat, expanding the sources of CHP and improving the flexibility and capacity for load adjustment of nuclear power units.

[0004] Currently, peak shaving for nuclear power units is typically achieved by adjusting the reactor's output power. For pressurized water reactors, control rod displacement and boric acid solution concentration are generally used as control variables to achieve reactor load tracking control. This adjustment method has a significant impact on the lifespan and operational safety of nuclear power units. Therefore, considering safety and economic factors, operating nuclear power units in my country generally do not participate in grid peak shaving and operate at base load. However, with the increasing pressure on grid peak-to-valley differences and renewable energy integration, the demand for grid peak shaving is constantly increasing, and nuclear power peak shaving is gradually being put on the agenda.

[0005] For nuclear power units that provide heating, extracting some steam from the turbine side of the secondary loop for heating without changing the nuclear reactor power will reduce the unit output. The output reduction caused by heating becomes a peak-shaving resource, making it possible to participate in grid peak shaving by adjusting the amount of steam extracted without adjusting the nuclear reactor output power. Summary of the Invention

[0006] This invention provides a method and apparatus for peak shaving in a combined heat and power (CHP) nuclear power unit based on secondary loop adjustment. This avoids the safety hazards of traditional nuclear power peak shaving and helps improve the flexibility and scope of CHP nuclear power unit load adjustment. To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simple form as an introduction to the detailed description that follows.

[0007] According to a first aspect of the present invention, a peak-shaving method for a combined heat and power nuclear power unit based on secondary loop adjustment is provided, comprising:

[0008] Collect heat balance diagrams of cogeneration nuclear power units, and establish mass and energy balance equations for each stage of heaters in the secondary loop of the nuclear power unit based on the heat balance diagrams; wherein, heat storage tanks are installed in the secondary loop to flexibly adjust the steam extraction rate and broaden the range of electrical load adjustment;

[0009] The mass and energy balance equations of each stage heater are converted into steam-water distribution equations. Based on the steam-water distribution equations, the regenerative steam extraction rate of each stage of the secondary loop of the nuclear power unit is further obtained, and it is verified whether the minimum steam inlet flow rate of the low-pressure cylinder of the secondary loop is met. If it is met, the turbine power is further solved using the work equation of the secondary loop of the nuclear power unit. Without changing the output power of the nuclear reactor, the minimum turbine power is calculated based on the maximum value of the regenerative steam extraction rate, and the maximum turbine power is calculated based on the minimum value of the regenerative steam extraction rate.

[0010] The range for adjusting the electrical load of nuclear power units is defined as less than or equal to the maximum turbine power and greater than or equal to the minimum turbine power, and peak shaving is carried out according to the range for adjusting the electrical load.

[0011] In one embodiment, the step of establishing the mass and energy balance equations for each stage of the heaters in the secondary loop of the nuclear power unit based on the heat balance diagram further includes:

[0012] The mass balance equation is:

[0013]

[0014] In the formula, The steam extraction rate for the i-th stage of regenerative heating is expressed in t / h. This refers to the exhaust flow rate of the low-pressure cylinder. For heating steam extraction flow rate; The main steam flow rate through the secondary reheater to the seventh-stage heater;

[0015] First stage heater:

[0016]

[0017] Second stage heater:

[0018]

[0019] Third-stage heater:

[0020]

[0021] Fourth stage heater:

[0022]

[0023] Deaerator:

[0024]

[0025] Sixth stage heater:

[0026]

[0027] Seventh stage heater:

[0028] ;

[0029] In the formula, Main steam flow rate, in t / h; The enthalpy of the feedwater for the i-th stage heater; Let be the hydrophobic enthalpy of the i-th stage heater.

[0030] In one embodiment, the step of converting the mass and energy balance equations of each stage of the heaters into a steam-water distribution equation further includes:

[0031] When the heat storage tank is not in operation, the formula for converting the mass and energy balance equations of each stage of the heater into the steam-water distribution equation is as follows:

[0032]

[0033] In the formula, Enthalpy rise of feedwater for stage i heater: = ; Here is the extraction enthalpy; A is the system matrix; This is the enthalpy of the extracted steam from the turbine through the secondary reheater to the seventh-stage heater.

[0034] When the heat storage tank is put into operation, the formula for converting the mass and energy balance equations of each stage of the heater into the steam-water distribution equation is as follows:

[0035]

[0036] In the formula, m aThe steam flow rate to the heat storage tank.

[0037] In one embodiment, the system matrix A in this method is:

[0038]

[0039] In the formula, For regenerative steam extraction enthalpy drop: = ; For the enthalpy drop of the heater by condensation; ; The hydrophobic enthalpy of the i-th stage heater; Let enthalpy be the enthalpy of the i-th stage of regenerative steam extraction.

[0040] In one embodiment, the method further includes the step of obtaining the regenerative steam extraction rate of each stage of the secondary loop of the nuclear power unit based on the steam-water distribution equation, and verifying whether the minimum steam inlet flow rate of the low-pressure cylinder of the secondary loop is met:

[0041] Formula used:

[0042]

[0043] In the formula, This is the sum of steam leakage from the shaft seal and steam leakage from the valve stem of the high-pressure cylinder. This is the minimum steam intake for the low-pressure cylinder that the unit itself must meet;

[0044] Verify whether the regenerative steam extraction rate meets the minimum steam inlet flow rate requirement of the low-pressure cylinder.

[0045] If not, the feedwater flow rate and the i-th stage regenerative steam extraction rate in the steam-water distribution equation are reset until the steam extraction rate meets the minimum steam inlet flow rate of the low-pressure cylinder.

[0046] In one embodiment, the method uses the work equation of the secondary loop of the nuclear power unit to solve for the turbine power, calculates the minimum turbine power based on the maximum value of the heating steam extraction without changing the nuclear reactor output power, and calculates the maximum turbine power based on the minimum value of the heating steam extraction. The steps further include:

[0047] The work equation is:

[0048]

[0049] In the formula, The main steam enthalpy value; For reheating, the enthalpy rise of the hot section; Exclude the steam enthalpy value of the low-pressure cylinder; This represents the enthalpy difference between the two ends of the steam-water separator.

[0050] In one embodiment, the method uses the work equation of the secondary loop of the nuclear power unit to solve for the turbine power, calculates the minimum turbine power based on the maximum value of the heating steam extraction without changing the nuclear reactor output power, and calculates the maximum turbine power based on the minimum value of the heating steam extraction. The steps further include:

[0051] The maximum value of the steam extraction rate is selected using the following formula:

[0052]

[0053] In the formula, The maximum steam extraction flow rate for heating is designed for nuclear power units. The heating steam extraction rate is the minimum steam inlet rate of the low-pressure cylinder, and the unit is t / h.

[0054] The turbine power is solved using the work equation of the secondary circuit of the nuclear power unit. Without changing the output power of the nuclear reactor, the minimum turbine power is calculated based on the maximum value of the heating extraction steam. The minimum value of the heating extraction steam is the minimum extraction steam to satisfy the current heating. When there is no heating, it is taken as 0. At this time, the steam intake of the low-pressure cylinder reaches the maximum value, and the turbine power also reaches the maximum value.

[0055] In one embodiment, the step of peak shaving according to the electrical load adjustment range in the method further includes:

[0056] The duration of each day during the heating season should be divided into at least two time periods.

[0057] Collect actual daily electrical load data of nuclear power units in combined heat and power (CHP) systems. Based on the actual peak-shaving needs of the power grid, determine the time periods during which the unit's power generation needs to be reduced or increased, and then determine the amount of change in power generation needed to be reduced or increased during those time periods.

[0058] In one embodiment, the step of peak shaving based on the electrical load adjustment range in the method further includes:

[0059] The heating season is divided into six time periods based on the length of each day: 0:00-4:00, 4:00-8:00, 8:00-12:00, 12:00-16:00, 16:00-20:00, and 20:00-24:00.

[0060] Collect actual daily electrical load data of nuclear power units in combined heat and power (CHP) systems. Based on the actual peak-shaving needs of the power grid, determine the time periods during which the unit's power generation needs to be reduced or increased, and then determine the amount of change in power generation needed to be reduced or increased during those time periods.

[0061] In one embodiment, the step of peak shaving according to the electrical load adjustment range in the method further includes:

[0062] Under the condition of maintaining the nuclear reactor output power unchanged, that is, under the premise of the main steam flow rate unchanged, the load demand of each of the six time periods is evaluated, and the strategy is optimized by adjusting the unit extraction steam rate and the charging and releasing rate of the heat storage tank.

[0063] Based on the steam-water distribution equation and the work equation, the corresponding relationship between electrical power and heat load is derived. Therefore, the change in heat load is calculated based on the change in power generation, and the change in steam extraction is determined using the following formula:

[0064] △

[0065] In the formula, △ Steam extraction change, in t / h; This represents the change in heat load, expressed in MW. This is the enthalpy value of steam extraction. The values ​​represent hydrophobic enthalpy, all in kJ / kg.

[0066] In one embodiment, the step of peak shaving according to the electrical load adjustment range in the method further includes:

[0067] During periods of reduced power generation load, the amount of extracted steam is increased and the heat is stored in the thermal storage tank to reduce power output; by storing heat in the thermal storage tank, the amount of extracted steam in the secondary loop is changed to achieve flexible peak shaving of the nuclear power unit.

[0068] In one embodiment, the step of peak shaving according to the electrical load adjustment range in the method further includes:

[0069] During periods of increased power generation load, the heat stored in the thermal storage tank is released to reduce the amount of steam extracted, thereby increasing power output. By releasing heat from the thermal storage tank, the amount of steam extracted in the secondary loop is changed to achieve flexible peak shaving for nuclear power units.

[0070] According to a second aspect of the present invention, a peak-shaving device for a combined heat and power nuclear power unit based on secondary loop adjustment is provided.

[0071] In one embodiment, the device includes a balance equation establishment module, a steam turbine power calculation module, and a peak-shaving module; wherein,

[0072] The equilibrium equation establishment module is used to collect the heat balance diagrams of cogeneration nuclear power units and establish the mass and energy balance equations of each stage of the heaters in the secondary loop of the nuclear power unit based on the heat balance diagrams.

[0073] The turbine power calculation module is used to convert the mass and energy balance equations of each stage heater into steam-water distribution equations. Based on the steam-water distribution equations, it further obtains the regenerative steam extraction amount of each stage of regeneration in the secondary loop of the nuclear power unit and verifies whether it meets the minimum steam inlet flow condition of the low-pressure cylinder of the secondary loop. If it does, it further uses the work equation of the secondary loop of the nuclear power unit to solve the turbine power. Without changing the output power of the nuclear reactor, it calculates the minimum turbine power based on the maximum value of the regenerative steam extraction amount and the maximum turbine power based on the minimum value of the regenerative steam extraction amount.

[0074] The peak-shaving module has a load adjustment range for nuclear power units that is less than or equal to the maximum turbine power and greater than or equal to the minimum turbine power. It is used to perform peak shaving based on the load adjustment range.

[0075] In one embodiment, a heat storage tank is provided in the secondary circuit of the device; the peak-shaving module further includes:

[0076] During periods of reduced power generation load, the increased steam extraction is stored in a thermal storage tank to reduce power generation output.

[0077] In one embodiment, the peak-shaving module in the device further includes:

[0078] During periods of increased power generation load, steam is extracted and released to boost power output.

[0079] According to a third aspect of the present invention, a computer device is provided.

[0080] In some embodiments, the computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method of the first aspect.

[0081] According to a fourth aspect of the present invention, a computer-readable storage medium is provided.

[0082] In some embodiments, a computer program is stored on a computer-readable storage medium; the computer program is executed by a processor to perform the steps of the method as described in the first aspect.

[0083] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0084] This invention proposes a peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment. It suggests adding a thermal storage tank to further enhance peak-shaving flexibility and provides a calculation method for the electrical load adjustment range after adding the thermal storage tank. This avoids the safety hazards of traditional nuclear power peak-shaving and facilitates the participation of nuclear power units in peak-shaving. Simultaneously, introducing a thermal storage device into the secondary loop not only improves the stability and safety of heating but also achieves partial thermoelectric decoupling to a certain extent. This helps improve the flexibility and scope of thermoelectric load adjustment for cogeneration nuclear power units, making it a feasible peak-shaving strategy.

[0085] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0086] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0087] Figure 1 This is a flowchart of a peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment provided in an embodiment of this application;

[0088] Figure 2 This is a heat balance diagram of a combined heat and power nuclear power unit provided in an embodiment of this application;

[0089] Figure 3 This is a schematic diagram of the thermoelectric coupling characteristics of a combined heat and power nuclear power unit provided in an embodiment of this application;

[0090] Figure 4 This is a heat balance diagram of a combined heat and power nuclear power unit including a heat storage tank, provided in an embodiment of this application.

[0091] Figure 5 This is a schematic diagram of the thermoelectric coupling characteristics of a combined heat and power nuclear power unit including a heat storage tank, provided in an embodiment of this application;

[0092] Figure 6 This is a schematic diagram of the actual daily electrical load data of a combined heat and power nuclear power unit provided in an embodiment of this application;

[0093] Figure 7 This is a schematic diagram of the average daily electrical load data of a combined heat and power nuclear power unit provided in an embodiment of this application;

[0094] Figure 8 This is a schematic diagram illustrating the optimized operation strategy of a combined heat and power nuclear power unit after adding a heat storage tank, as provided in the embodiments of this application.

[0095] Figure 9This is a structural diagram of the peak-shaving device for a cogeneration nuclear power unit based on secondary loop adjustment provided in the embodiments of this application;

[0096] Figure 10 This is a schematic diagram of the structure of a computer device according to an exemplary embodiment. Detailed Implementation

[0097] The following description and accompanying drawings fully illustrate specific embodiments described herein to enable those skilled in the art to practice them. Some embodiments may include or substitute parts and features of other embodiments. The scope of the embodiments herein encompasses the entire scope of the claims and all available equivalents thereof. Throughout this document, the terms “first,” “second,” etc., are used only to distinguish one element from another without requiring or implying any actual relationship or order between the elements. Indeed, a first element can also be referred to as a second element, and vice versa. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure, apparatus, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a structure, apparatus, or device. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the structure, apparatus, or device that includes said element. The various embodiments described herein are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0098] In this document, unless otherwise stated, the term "multiple" means two or more.

[0099] Figure 1 A flowchart of the peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment according to the present invention is shown, as follows: Figure 1 As shown:

[0100] S100: Collect the heat balance diagram of the combined heat and power nuclear power unit, and establish the mass and energy balance equations of each stage of the heaters in the secondary loop of the nuclear power unit based on the heat balance diagram; wherein, a heat storage tank is set in the secondary loop to flexibly adjust the steam extraction rate and broaden the range of electrical load adjustment.

[0101] S200: The mass and energy balance equations of each stage heater are converted into steam-water distribution equations. Based on the steam-water distribution equations, the regenerative steam extraction rate of each stage of the secondary loop of the nuclear power unit is further obtained, and it is verified whether the minimum steam inlet flow rate of the low-pressure cylinder of the secondary loop is met. If it is met, the turbine power is further solved using the work equation of the secondary loop of the nuclear power unit. Without changing the output power of the nuclear reactor, the minimum turbine power is calculated based on the maximum value of the regenerative steam extraction rate, and the maximum turbine power is calculated based on the minimum value of the regenerative steam extraction rate.

[0102] S300: The range of electric load adjustment for nuclear power units is less than or equal to the maximum turbine power and greater than or equal to the minimum turbine power, and peak shaving is carried out according to the range of electric load adjustment.

[0103] In specific implementation, according to Figure 2 Establish the mass and energy balance equations for each stage of the heaters in the secondary loop of a nuclear power unit:

[0104] The mass balance equation is:

[0105]

[0106] In the formula, The steam extraction rate for the i-th stage of regenerative heating is expressed in t / h. This refers to the exhaust flow rate of the low-pressure cylinder. For heating steam extraction flow rate; The main steam flow rate through the secondary reheater to the seventh-stage heater;

[0107] First stage heater:

[0108]

[0109] Second stage heater:

[0110]

[0111] Third-stage heater:

[0112]

[0113] Fourth stage heater:

[0114]

[0115] Deaerator:

[0116]

[0117] Sixth stage heater:

[0118]

[0119] Seventh stage heater:

[0120]

[0121] In the formula, Main steam flow rate, in t / h; The enthalpy of the feedwater for the i-th stage heater; Let be the hydrophobic enthalpy of the i-th stage heater.

[0122] In practical implementation, the energy equations for each stage of the heaters in the secondary loop of the nuclear power unit are transformed into steam-water distribution equations:

[0123]

[0124] In the formula, Enthalpy rise of feedwater for stage i heater: = ; Here is the extraction enthalpy; A is the system matrix; This is the enthalpy of the extracted steam from the turbine through the secondary reheater to the seventh-stage heater.

[0125] Furthermore,

[0126]

[0127] In the formula, For regenerative steam extraction enthalpy drop: = ; For the enthalpy drop of the heater condensate: ; The hydrophobic enthalpy of the i-th stage heater; Let enthalpy be the enthalpy of the i-th stage of regenerative steam extraction.

[0128] Furthermore, the main parameters of the steam-water distribution equation are set. Specifically, the main parameters include the feedwater flow rate and the i-th stage regenerative steam extraction rate.

[0129] Furthermore, using the steam-water distribution equation, the amount of regenerative steam extracted at each stage of the secondary loop in a combined heat and power (CHP) nuclear power unit is calculated.

[0130] In practical implementation, after calculating the regenerative steam extraction rates at each stage of the secondary loop, the following formula is used:

[0131]

[0132] In the formula, This is the sum of steam leakage from the shaft seal and steam leakage from the valve stem of the high-pressure cylinder. This is the minimum steam intake for the low-pressure cylinder that the unit itself must meet;

[0133] Verify whether the extraction steam volume meets the minimum steam inlet flow rate requirement of the low-pressure cylinder.

[0134] If not, the feedwater flow rate and the i-th stage regenerative steam extraction rate in the steam-water distribution equation are reset until the steam extraction rate meets the minimum steam inlet flow rate of the low-pressure cylinder.

[0135] In practical implementation, the work equation is as follows:

[0136]

[0137] In the formula, The main steam enthalpy value; For reheating, the enthalpy rise of the hot section; Exclude the steam enthalpy value of the low-pressure cylinder; This represents the enthalpy difference between the two ends of the steam-water separator.

[0138] Specifically, the power of the turbine under this operating condition is first solved by using the work equation of the secondary circuit of the nuclear power unit. The purpose is to quantitatively calculate the power generation of the nuclear power unit when it operates at a certain steam extraction rate without changing the output power of the nuclear reactor, and then characterize the adjustment of electrical load achieved by simply adjusting the steam extraction rate.

[0139] like Figure 3 As shown, this application calculates the thermoelectric coupling characteristics of the unit under four operating conditions: THA, 90% THA, 80% THA, and 70% THA, to further illustrate the above steps; the solid line in the figure represents the THA operating condition, and the dashed lines from top to bottom represent 90% THA, 80% THA, and 70% THA respectively.

[0140] Based on this, this application considers adjusting the power output of nuclear power units without changing the output power of the nuclear reactor, so as to meet the peak shaving function during the corresponding period of the day.

[0141] Furthermore, this application regulates the electrical load solely by extracting steam.

[0142] In practical implementation, the minimum turbine power of the nuclear power unit is calculated without changing the nuclear reactor output power. When the electrical load is adjusted to the minimum power point, the regenerative steam extraction rate is selected according to the following rules:

[0143]

[0144] In the formula, To design the maximum steam extraction flow rate for heating in nuclear power units, The heating steam extraction rate corresponds to the minimum steam inlet rate of the low-pressure cylinder, and the unit is t / h. In actual operation, the maximum allowable heating steam extraction rate of the unit is the smaller of the two values.

[0145] In practice, the maximum turbine power of the nuclear power unit is calculated without changing the output power of the nuclear reactor. When the electrical load is adjusted to the maximum power point, the steam inlet of the low-pressure cylinder in the secondary loop of the nuclear power unit reaches its maximum value, and the regenerative extraction steam flow is 0.

[0146] In practice, the power outputs of the two turbines are recorded, and the range between these two power outputs represents the unit's electrical load adjustment range under the specified feedwater flow rate. Considering that the nuclear reactor output power remains unchanged, the thermal and electrical load operating range of the cogeneration nuclear power unit exhibits linear characteristics, indicating that the unit can adjust its electrical load within a certain range according to changes in daily heat load demand, thus possessing corresponding peak-shaving capabilities and capacity.

[0147] In some embodiments of this application, a heat storage tank is added to further enhance the flexibility and adjustability of the power adjustment of the nuclear power unit.

[0148] like Figure 4 As shown, after introducing the heat storage tank into the original secondary loop system, repeat the above steps:

[0149] By establishing the thermoelectric coupling characteristics of a nuclear power unit with an added heat storage tank, the following new steam-water distribution equation is obtained:

[0150]

[0151] In the formula, in the formula, The system matrix is ​​the same as the matrix in the preceding steps. The same. After adding the heat storage tank, the unit's operating domain becomes as follows: Figure 5 As shown (i.e., changing from the original AB to A1B1A2B2), its load flexibility adjustment space is increased, and a certain degree of thermoelectric decoupling is achieved.

[0152] In practice, the heating season is divided into at least two time periods each day; the actual electrical load data of the combined heat and power nuclear power units are collected throughout the day; based on the actual demand of the power grid for peak shaving, the time period in which the generating power of the units needs to be reduced or increased is determined, and then the amount of change in generating power that needs to be reduced or increased during that time period is determined.

[0153] In some embodiments of this application, during the evening hours of 16:00 to 20:00 in the heating season, new energy sources such as wind and solar power cannot provide sufficient power supply, leading to power shortages during this period. To better address this issue, the length of this period is set as an average duration, dividing the 24-hour period into six segments: 0:00–4:00; 4:00–8:00; 8:00–12:00; 12:00–16:00; 16:00–20:00; and 20:00–24:00. The actual daily electrical load data of the combined heat and power (CHP) nuclear power units are collected. Based on the power load demand, the time periods requiring reduced or increased unit power generation are selected, along with the available capacity for such reductions or increases during those periods.

[0154] In this embodiment, while maintaining a constant reactor output power (i.e., a constant main steam flow rate), the load demand for each of the six selected time periods is assessed. Operational strategy optimization is achieved by adjusting the unit's extraction steam rate and the charging and releasing rates of the thermal storage tank. The thermoelectric coupling characteristics obtained in the preceding steps allow for the calculation of the relationship between electrical and thermal loads, thus enabling the calculation of changes in thermal load. The extraction steam rate can then be obtained using the following formula:

[0155] △

[0156] At this time △ The change in steam extraction rate is expressed in t / h. Real-time heat load, MW; This is the enthalpy value of steam extraction. The values ​​represent hydrophobic enthalpy, all in kJ / kg.

[0157] In practice, during periods of reduced power generation load, the increased steam extraction is stored in a thermal storage tank to suppress power generation output; during periods of increased power generation load, the extracted steam is released to increase power generation output.

[0158] Specifically, during periods of reduced power generation load, the increased steam extraction is stored in a thermal storage tank to lower power output; then, during periods of increased power generation load, it is released to reduce the amount of steam extracted from the turbine and increase power output. This ultimately yields the unit's load adjustment capability and the corresponding thermal storage tank charging and discharging behavior at different times without changing the reactor power.

[0159] In summary, this application, based on the premise that the nuclear power unit using combined heat and power (CHP) operates with a constant reactor output power, achieves peak shaving participation by adjusting the extraction steam volume from the secondary loop. By introducing a thermal storage device into the heating system, "thermal-electric decoupling" is achieved to a certain extent, enhancing the flexibility and effective scope of the nuclear power unit's participation in power peak shaving. The nuclear power participation in grid peak shaving mode involved in this application differs from the traditional method of participating in peak shaving by adjusting the output power on the nuclear island side, thereby improving the overall economic benefits of the unit and reducing the risks associated with traditional nuclear power peak shaving methods. The peak shaving strategy involved in this application helps increase the peak shaving resources of the power system and effectively promotes the consumption of renewable energy sources such as wind and solar power.

[0160] This application provides a specific embodiment to illustrate the above steps:

[0161] Please see Figures 6-8 This embodiment is an AP1000-class nuclear power unit with a design power of 1203MW. It has 7 stages of heaters, and the fifth stage of regenerative extraction section is used for heating extraction.

[0162] Step a: Collect the heat balance diagram of the combined heat and power unit.

[0163] Step b: Based on the heat balance diagram, establish the mass and energy balance equations for each stage of the heater.

[0164] Step c: Rearrange the energy equations of each heater in step b into the following matrix equation form.

[0165]

[0166]

[0167] Step d: Set the main parameters of the steam-water distribution equation in step c: feedwater flow rate and heating steam extraction rate, as shown in the table below:

[0168]

[0169] Step e: Use the steam-water distribution equation from step c to solve for the extraction steam rate at each stage of regeneration. The solution results are shown in the table below:

[0170]

[0171] The error between the model and the design data in the unit's heat balance diagram is within 3%, indicating that the model verification is reasonable.

[0172] Step f: Solve for the turbine power under this operating condition using the work equation:

[0173]

[0174] Calculation yields =1201MW, which is within a reasonable range from the actual 1203MW, proving that the model is feasible.

[0175] Step g: Calculate the minimum electrical power of the nuclear power unit without changing the nuclear reactor output power. At this point, when the electrical load is adjusted to the minimum power point, the steam extraction rate for heating is selected according to the following rules.

[0176]

[0177] In the formula, The maximum steam extraction flow rate for heating is designed for the unit. The heating extraction steam flow rate corresponds to the minimum steam inlet flow rate of the low-pressure cylinder, and the unit is t / h. In actual operation, the maximum allowable heating extraction steam flow rate of the unit is the smaller of these two values. In this embodiment, 1500t / h; =3258t / h. In summary, =1500t / h.

[0178] Corresponding minimum electrical load

[0179] Step h: Calculate the maximum electrical power of the nuclear power unit without changing the output power of the nuclear reactor, at which point the steam extraction rate for heating is 0.

[0180] The calculation is as follows:

[0181] =0 t / h

[0182]

[0183] Step i: Record the turbine power calculated in steps g and h. It can be seen that the power between the two is the range of unit electrical load adjustment under the specified feedwater flow rate, which is 996-1263MW. The load can be adjusted by changing the steam extraction rate.

[0184] Step j: Obtain the actual data for one day from this unit, as shown in the table below. Specific data is as follows: Figure 6 As shown.

[0185]

[0186] The averaged data is shown in the table below. Specific data is as follows: Figure 7 As shown.

[0187]

[0188] Step k: Assume that from 4:00 AM to 2:00 PM on a certain day, sunlight is abundant, allowing for increased steam extraction to reduce electrical load and absorb more renewable energy. The excess steam extracted is stored in a thermal storage tank. From 4:00 PM to 8:00 PM, sunlight is reduced, and wind power has not yet been supplied in time. Therefore, peak output is required to release the heat stored in the thermal storage tank. The unit can reduce steam extraction or use only the heat from the storage tank, thus increasing the unit's peak output capacity. From 8:00 PM to 4:00 AM, electricity consumption is low at night, and there is a need to absorb wind power, resulting in a load reduction requirement.

[0189] In summary, the peak power output period is selected from 16:00 to 20:00, and the power load is reduced during other periods.

[0190] Step 1: Assume that the unit can maintain its maximum power of 1263MW during the period from 16:00 to 20:00. The calculated changes in steam extraction during each time period are shown in the table below.

[0191]

[0192] Among them, the change in steam extraction rate is - for decrease and + for increase.

[0193] Step m: The increased steam extraction rate is stored in the heat storage tank during the period from 20:00 to 16:00, and then released during the period from 16:00 to 20:00, so as to obtain the final peak output capacity and the corresponding heat storage tank charging and discharging situation.

[0194] The results are shown in the table below. Figure 7 .

[0195]

[0196] The charging and discharging rates of the thermal storage tank are shown in the figure, where - represents storage and + represents release.

[0197] In summary, the disadvantages of not having a thermal storage tank are mitigated by adding one, and the electricity load can be increased by 122MW during the period from 16:00 to 20:00. The peak-shaving capacity can reach 488MW·h during other periods, thus improving the absorption of renewable energy.

[0198] The data used in this embodiment is only for introducing the scheduling strategy. In actual operation, the time period can be re-divided according to the specific peak-shaving demand, or the amount of steam extracted from the unit and the storage status of the heat storage tank can be changed according to the actual capacity of the heat storage tank.

[0199] It should be understood that although the steps in the flowchart are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order constraint on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the diagram may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0200] Please see Figure 9 One embodiment of this application provides a peak-shaving device for a combined heat and power nuclear power unit based on secondary loop adjustment, including a balance equation establishment module 10, a turbine power calculation module 20, and a peak-shaving module 30; wherein,

[0201] The balance equation establishment module 10 is used to collect the heat balance diagram of the cogeneration nuclear power unit and establish the mass and energy balance equations of each stage of the heaters in the secondary loop of the nuclear power unit based on the heat balance diagram; wherein, a heat storage tank is set in the secondary loop to flexibly adjust the steam extraction rate and broaden the range of electrical load adjustment.

[0202] The turbine power calculation module 20 is used to convert the mass and energy balance equations of each stage heater into steam-water distribution equations. Based on the steam-water distribution equations, it further obtains the regenerative steam extraction amount of each stage of regeneration in the secondary loop of the nuclear power unit and verifies whether it meets the minimum steam inlet flow condition of the low-pressure cylinder of the secondary loop. If it does, it further uses the work equation of the secondary loop of the nuclear power unit to solve the turbine power. Without changing the output power of the nuclear reactor, it calculates the minimum turbine power based on the maximum value of the regenerative steam extraction amount and the maximum turbine power based on the minimum value of the regenerative steam extraction amount.

[0203] The peak-shaving module 30 has a load adjustment range for the nuclear power unit that is less than or equal to the maximum turbine power and greater than or equal to the minimum turbine power. It is used for peak shaving based on this load adjustment range. Specifically, a heat storage tank is installed in the secondary loop. This module further includes: storing the increased extraction steam in the heat storage tank during periods of reduced power generation load to lower power output; and releasing the extraction steam during periods of increased power generation load to increase power output.

[0204] Specific limitations regarding the peak-shaving device for cogeneration nuclear power units based on secondary loop adjustment can be found in the above-mentioned limitations on the peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment, and will not be repeated here. Each module in the aforementioned peak-shaving device for cogeneration nuclear power units based on secondary loop adjustment can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the operations corresponding to each module.

[0205] In another embodiment of this application, a computer device is provided, which may be a server, and its internal structure diagram may be as follows. Figure 10 As shown, the computer device includes a processor, memory, and a network interface connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database stores static and dynamic information data. The network interface communicates with external terminals via a network connection. When the computer program is executed by the processor, it implements the steps in the above method embodiments.

[0206] Those skilled in the art will understand that Figure 10 The structure shown is merely a block diagram of a portion of the structure related to the present invention and does not constitute a limitation on the computer device to which the present invention is applied. A specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0207] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the method embodiments described above.

[0208] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0209] This invention is not limited to the structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this invention is limited only by the appended claims.

Claims

1. A peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment, characterized in that, include: Collect the heat balance diagram of the combined heat and power nuclear power unit, and establish the mass and energy balance equations of each stage heater in the secondary loop of the nuclear power unit based on the heat balance diagram; wherein, the secondary loop is equipped with a heat storage tank to flexibly adjust the steam extraction rate and broaden the range of electrical load adjustment; The mass and energy balance equations of each stage heater are converted into steam-water distribution equations. Based on the steam-water distribution equations, the regenerative steam extraction rate of each stage of the secondary loop of the nuclear power unit is further obtained, and it is verified whether the minimum steam inlet flow rate of the low-pressure cylinder of the secondary loop is met. If it is met, the turbine power is further solved using the work equation of the secondary loop of the nuclear power unit. Without changing the output power of the nuclear reactor, the minimum turbine power is calculated based on the maximum value of the regenerative steam extraction rate, and the maximum turbine power is calculated based on the minimum value of the regenerative steam extraction rate. The electric load adjustment range of the nuclear power unit is defined as less than or equal to the maximum steam turbine power and greater than or equal to the minimum steam turbine power. Peak shaving is carried out according to the electric load adjustment range, including: dividing each day of the heating season into at least two time periods of equal duration; collecting the actual electric load data of the combined heat and power nuclear power unit within a day; determining the time period in which the unit's power generation needs to be reduced or increased according to the actual peak shaving needs of the power grid; and then determining the amount of change in the power generation that needs to be reduced or increased during the time period. The step of establishing the mass and energy balance equations for each stage of the heaters in the secondary circuit of the nuclear power unit based on the heat balance diagram further includes: The mass balance equation is: In the formula, The steam extraction rate for the i-th stage of regenerative heating is expressed in t / h. This refers to the exhaust flow rate of the low-pressure cylinder. For heating steam extraction flow rate; The main steam flow rate through the secondary reheater to the seventh-stage heater; First stage heater: Second stage heater: Third-stage heater: Fourth stage heater: Deaerator: Sixth stage heater: Seventh stage heater: ； In the formula, Main steam flow rate, in t / h; The enthalpy of the feedwater for the i-th stage heater; The hydrophobic enthalpy of the i-th stage heater; The enthalpy of the i-th stage regenerative extraction steam; The step of converting the mass and energy balance equations of the heaters at each stage into steam-water distribution equations further includes: When the heat storage tank is not in operation, the formula for converting the mass and energy balance equations of each stage of the heater into a steam-water distribution equation is as follows: In the formula, Enthalpy rise of feedwater for stage i heater: = ; Here is the extraction enthalpy; A is the system matrix; The enthalpy of the extracted steam from the turbine through the secondary reheater to the seventh-stage heater; When the heat storage tank is put into operation, the formula for converting the mass and energy balance equations of the heaters at each stage into the steam-water distribution equation is as follows: In the formula, m a The steam flow rate to the heat storage tank.

2. The peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment according to claim 1, characterized in that, The system matrix A is: In the formula, For regenerative steam extraction enthalpy drop: = ; For the enthalpy drop of the heater by condensation; ; The hydrophobic enthalpy of the i-th stage heater; Let enthalpy be the enthalpy of the i-th stage of regenerative steam extraction.

3. The peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment according to claim 2, characterized in that, The steps of further obtaining the regenerative steam extraction rate of each stage of the secondary loop of the nuclear power unit based on the steam-water distribution equation, and verifying whether the minimum steam inlet flow rate of the low-pressure cylinder of the secondary loop is met, further include: Formula used: In the formula, This is the sum of steam leakage from the shaft seal and steam leakage from the valve stem of the high-pressure cylinder. This is the minimum steam intake for the low-pressure cylinder that the unit itself must meet; Verify whether the regenerative steam extraction rate meets the minimum steam inlet flow condition of the low-pressure cylinder; If the conditions are not met, the feedwater flow rate and the i-th stage regenerative steam extraction rate in the steam-water distribution equation are reset until the steam extraction rate meets the minimum steam inlet flow rate of the low-pressure cylinder.

4. The peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment according to claim 3, characterized in that, The steps of solving the turbine power using the work equations of the secondary loop of the nuclear power unit, calculating the minimum turbine power based on the maximum value of the heating steam extraction without changing the nuclear reactor output power, and calculating the maximum turbine power based on the minimum value of the heating steam extraction further include: The work equation is: In the formula, The main steam enthalpy value; For reheating, the enthalpy rise of the hot section; Exclude the steam enthalpy value of the low-pressure cylinder; This represents the enthalpy difference between the two ends of the steam-water separator.

5. The peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment according to claim 4, characterized in that, The steps of solving the turbine power using the work equations of the secondary loop of the nuclear power unit, calculating the minimum turbine power based on the maximum value of the heating steam extraction without changing the nuclear reactor output power, and calculating the maximum turbine power based on the minimum value of the heating steam extraction further include: The maximum value of the extraction steam rate is selected using the following formula: In the formula, The maximum steam extraction flow rate for heating is designed for nuclear power units. The heating steam extraction rate is the minimum steam inlet rate of the low-pressure cylinder, and the unit is t / h. The turbine power is solved using the work equation of the secondary circuit of the nuclear power unit. Without changing the output power of the nuclear reactor, the minimum turbine power is calculated based on the maximum value of the heating extraction steam volume. The minimum value of the heating extraction steam volume is the minimum extraction steam volume that satisfies the current heating supply. When there is no heating, it is taken as 0. At this time, the steam volume of the low-pressure cylinder reaches the maximum value, and the turbine power also reaches the maximum value.

6. The peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment according to claim 1, characterized in that, The step of peak shaving based on the electrical load adjustment range further includes: The heating season is divided into six time periods of equal duration: 0:00-4:00, 4:00-8:00, 8:00-12:00, 12:00-16:00, 16:00-20:00, and 20:00-24:

00. Collect the actual daily electrical load data of the combined heat and power nuclear power unit, determine the time period during which the unit's power generation needs to be reduced or increased based on the actual peak-shaving demand of the power grid, and then determine the amount of change in the power generation that needs to be reduced or increased during the specified time period.

7. The peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment according to claim 6, characterized in that, The step of peak shaving based on the electrical load adjustment range further includes: Under the condition of maintaining the nuclear reactor output power unchanged, that is, under the premise of maintaining the main steam flow rate unchanged, the load demand of each of the six time periods is evaluated, and the strategy is optimized by adjusting the unit extraction steam rate and the charging and releasing rate of the heat storage tank. Based on the steam-water distribution equation and the work equation, the correspondence between electrical power and heat load is derived. Therefore, the change in heat load is calculated based on the change in power generation, and the change in steam extraction is determined using the following formula: △ In the formula, △ Steam extraction change, in t / h; This represents the change in heat load, expressed in MW. This is the enthalpy value of steam extraction. The values ​​represent hydrophobic enthalpy, all in kJ / kg.

8. The peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment according to claim 7, characterized in that, The step of peak shaving based on the electrical load adjustment range further includes: During the period of reduced electrical load, the steam extraction rate is increased and the heat is stored in the heat storage tank to reduce power generation output; by storing heat in the heat storage tank, the steam extraction rate of the secondary loop is changed to achieve flexible peak shaving of the nuclear power unit.

9. The peak-shaving method for cogeneration nuclear power units based on secondary loop adjustment according to claim 8, characterized in that, The step of peak shaving based on the electrical load adjustment range further includes: During periods of increased electrical load, the heat stored in the thermal storage tank is released to reduce the steam extraction rate and increase power generation output. By releasing heat through the thermal storage tank, the steam extraction rate in the secondary loop is changed to achieve flexible peak shaving for the nuclear power unit.

10. A peak-shaving device for a combined heat and power nuclear power unit based on secondary loop adjustment, characterized in that, It includes a balance equation establishment module, a steam turbine power calculation module, and a peak-shaving module; among which, The balance equation establishment module is used to collect the heat balance diagram of the cogeneration nuclear power unit and establish the mass and energy balance equations of each stage heater in the secondary loop of the nuclear power unit based on the heat balance diagram; wherein, the secondary loop is equipped with a heat storage tank to flexibly adjust the steam extraction rate and broaden the range of electrical load adjustment; The turbine power calculation module is used to convert the mass and energy balance equations of the heaters at each stage into steam-water distribution equations. Based on the steam-water distribution equations, it further obtains the regenerative steam extraction amount of each stage of the secondary loop of the nuclear power unit and verifies whether it meets the minimum steam inlet flow condition of the low-pressure cylinder of the secondary loop. If it does, it further uses the work equations of the secondary loop of the nuclear power unit to solve for the turbine power. Without changing the output power of the nuclear reactor, it calculates the minimum turbine power based on the maximum value of the regenerative steam extraction amount and the maximum turbine power based on the minimum value of the regenerative steam extraction amount. The peak-shaving module defines the electrical load adjustment range of the nuclear power unit as less than or equal to the maximum turbine power and greater than or equal to the minimum turbine power. It is used to perform peak shaving according to the electrical load adjustment range, including: dividing each day of the heating season into at least two time periods of equal duration; collecting the actual electrical load data of the combined heat and power nuclear power unit within a day; determining the time period in which the unit's power generation needs to be reduced or increased based on the actual peak-shaving demand of the power grid; and then determining the amount of change in the power generation that needs to be reduced or increased during the time period. The establishment of mass and energy balance equations for each stage of the heaters in the secondary circuit of the nuclear power unit based on the heat balance diagram further includes: The mass balance equation is: In the formula, The steam extraction rate for the i-th stage of regenerative heating is expressed in t / h. This refers to the exhaust flow rate of the low-pressure cylinder. For heating steam extraction flow rate; The main steam flow rate through the secondary reheater to the seventh-stage heater; First stage heater: Second stage heater: Third-stage heater: Fourth stage heater: Deaerator: Sixth stage heater: Seventh stage heater: ； In the formula, Main steam flow rate, in t / h; The enthalpy of the feedwater for the i-th stage heater; The hydrophobic enthalpy of the i-th stage heater; The enthalpy of the i-th stage regenerative extraction steam; The mass and energy balance equations of the heaters at each stage are converted into steam-water distribution equations, further including: When the heat storage tank is not in operation, the formula for converting the mass and energy balance equations of each stage of the heater into a steam-water distribution equation is as follows: In the formula, Enthalpy rise of feedwater for stage i heater: = ; Here is the extraction enthalpy; A is the system matrix; The enthalpy of the extracted steam from the turbine through the secondary reheater to the seventh-stage heater; When the heat storage tank is put into operation, the formula for converting the mass and energy balance equations of the heaters at each stage into the steam-water distribution equation is as follows: In the formula, m a The steam flow rate to the heat storage tank.

11. The peak-shaving device for a cogeneration nuclear power unit based on secondary loop adjustment according to claim 10, characterized in that, The system matrix A is: In the formula, For regenerative steam extraction enthalpy drop: = ; For the enthalpy drop of the heater by condensation; ; The hydrophobic enthalpy of the i-th stage heater; Let enthalpy be the enthalpy of the i-th stage of regenerative steam extraction.

12. The peak-shaving device for a cogeneration nuclear power unit based on secondary loop adjustment according to claim 11, characterized in that, Based on the steam-water distribution equation, the regenerative steam extraction rate of each stage of the secondary loop of the nuclear power unit is further obtained, and the verification of whether the minimum steam inlet flow rate of the low-pressure cylinder of the secondary loop is met further includes: Formula used: In the formula, This is the sum of steam leakage from the shaft seal and steam leakage from the valve stem of the high-pressure cylinder. This is the minimum steam intake for the low-pressure cylinder that the unit itself must meet; Verify whether the regenerative steam extraction rate meets the minimum steam inlet flow condition of the low-pressure cylinder; If the conditions are not met, the feedwater flow rate and the i-th stage regenerative steam extraction rate in the steam-water distribution equation are reset until the steam extraction rate meets the minimum steam inlet flow rate of the low-pressure cylinder.

13. The peak-shaving device for a cogeneration nuclear power unit based on secondary loop adjustment according to claim 12, characterized in that, The peak-shaving module further includes: During periods of reduced electrical load, the steam extraction rate is increased and the heat is stored in the thermal storage tank to reduce power generation output; during periods of increased electrical load, the heat stored in the thermal storage tank is released to reduce the steam extraction rate and increase power generation output; by storing and releasing heat in the thermal storage tank, the steam extraction rate in the secondary loop is changed to achieve flexible peak shaving of the nuclear power unit.

14. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1-9.

15. A computer-readable storage medium, characterized in that, It stores a computer program thereon; the computer program is executed by a processor to implement the method as described in any one of claims 1-9.

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