A method and system for evaluating the status of a nuclear power plant condenser half-side operation

Abstract

The present invention relates to a state assessment method and system for half-side operation of a condenser in a nuclear power plant, comprising the following steps: based on a condenser cooling pipe steam flow excitation model, calculating a standard span when the condenser is half-side in operation; judging whether the condenser meets the power operation requirements based on the standard span; if so, performing a failure assessment; if not, performing a risk assessment. The present invention ensures safe and reliable operation of the condenser, avoids risks, and improves the safety and reliability of the unit operation by comprehensively assessing the state of the cooling pipes when the condenser is half-side in operation in a nuclear power plant.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plant condensers, and more specifically to a state assessment method and system for half-side operation of a nuclear power plant condenser. Background Art

[0002] Using the basic theory of steam flow excitation of cooling pipes, a mathematical model for the calculation of the span of the support plate when the condenser of a nuclear power plant is half-operating is clearly given, and the actual span verification calculation is carried out using the condenser of a certain unit as an example. According to the three cooling pipe failure mode principles of friction, fatigue and shear, calculations are carried out under various working conditions, showing that the critical span of the friction mechanism under the winter half-row operation condition is close to the manufacturer's design value, which poses a risk and the power platform of the unit should be limited. Therefore, it is necessary to evaluate the status of the cooling pipes when the condenser of a nuclear power plant is half-operating. At present, there is no complete method to comprehensively evaluate the status of the cooling pipes when the condenser of a nuclear power plant is half-operating. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method and system for evaluating the status of half-side operation of a condenser in a nuclear power plant in view of the defects of the prior art.

[0004] The technical solution adopted by the present invention to solve the technical problem is: constructing a state assessment method for half-side operation of a condenser in a nuclear power plant, comprising the following steps:

[0005] Based on the steam flow excitation model of condenser cooling tube, the standard span of the condenser half-side operation is calculated;

[0006] judging whether the condenser meets the power operation requirement based on the standard span;

[0007] If yes, conduct failure assessment;

[0008] If no, conduct a risk assessment.

[0009] In the state assessment method for half-side operation of a condenser in a nuclear power plant according to the present invention, the calculation of the standard span of the half-side operation of the condenser based on the condenser cooling pipe steam flow excitation model includes:

[0010] Based on the steam flow excitation vibration model of the condenser cooling pipe, calculating the maximum deflection of the cooling pipe;

[0011] Based on the value conditions of the maximum deflection of the cooling pipe, the standard span of the condenser when half of the condenser is in operation is calculated.

[0012] In the state assessment method for half-side operation of a condenser in a nuclear power plant according to the present invention, judging whether the condenser meets the power operation requirement based on the standard span includes:

[0013] Get the actual span;

[0014] comparing the standard span with the actual span;

[0015] If the standard span is greater than or equal to the actual span, the condenser is judged not to meet the power operation requirement;

[0016] If the standard span is smaller than the actual span, it is determined that the condenser meets the power operation requirement.

[0017] In the state assessment method for half-side operation of a condenser in a nuclear power plant according to the present invention, if so, performing failure assessment includes:

[0018] If the condenser meets the power operation requirements, the fatigue critical span, the friction critical span and the shear critical span of the cooling tube are calculated;

[0019] Failure assessment is performed based on the fatigue critical span, the wear critical span, and the shear critical span.

[0020] In the state assessment method for half-side operation of a condenser in a nuclear power plant according to the present invention, the failure assessment based on the fatigue critical span, the friction critical span and the shear critical span comprises:

[0021] Determine whether the fatigue critical span, the friction critical span, and the shear critical span are all greater than actual values;

[0022] If yes, it is determined that the condenser half can operate at full power;

[0023] If not, it is determined that the condenser half cannot operate at full power.

[0024] In the method for evaluating the status of the half-side operation of a condenser in a nuclear power plant according to the present invention, the method further comprises:

[0025] If it is determined that the condenser half cannot be operated at full power, a risk assessment is performed.

[0026] In the state assessment method for half-side operation of a condenser in a nuclear power plant according to the present invention, the risk assessment comprises:

[0027] Calculating the critical flow velocity of the cooling pipe;

[0028] A risk assessment is performed based on the critical flow rate of the cooling pipe.

[0029] In the state assessment method for half-side operation of a condenser in a nuclear power plant according to the present invention, the risk assessment according to the critical flow velocity of the cooling pipe comprises:

[0030] comparing the critical flow rate of the cooling tube with the throat outlet flow rate of the condenser;

[0031] If the critical flow rate of the cooling pipe is greater than the throat outlet flow rate of the condenser, it is determined that the condenser is in a safe state;

[0032] If the critical flow rate of the cooling pipe is less than the throat outlet flow rate of the condenser, it is determined that the condenser is in a risky state, and a power reduction operation is performed.

[0033] In the state assessment method for half-side operation of a nuclear power plant condenser according to the present invention, if the critical flow rate of the cooling pipe is greater than the throat outlet flow rate of the condenser, then judging that the condenser is in a safe state includes:

[0034] Obtaining the amplitude of the cooling pipe;

[0035] Determining whether the cooling pipe is rubbed according to the amplitude of the cooling pipe;

[0036] If yes, then perform power reduction operation;

[0037] If not, it is determined that the condenser is in a safe operating state.

[0038] The present invention also provides a state assessment system for half-side operation of a condenser in a nuclear power plant, comprising:

[0039] A calculation unit, based on the steam flow excitation model of the condenser cooling pipe, calculates the standard span when the condenser is in half-side operation;

[0040] A judging unit, configured to judge whether the condenser meets the operation requirements based on the standard span;

[0041] A failure assessment unit, used for performing failure assessment when the condenser meets the power operation requirement;

[0042] The risk assessment unit is used to perform risk assessment when the condenser does not meet the power operation requirement.

[0043] The state assessment method and system for the half-side operation of the condenser of a nuclear power plant implemented in the present invention have the following beneficial effects: comprising the following steps: based on the steam flow excitation model of the condenser cooling pipe, calculating the standard span when the condenser is half-side in operation; judging whether the condenser meets the power operation requirements based on the standard span; if so, performing a failure assessment; if not, performing a risk assessment. The present invention ensures the safe and reliable operation of the condenser, avoids risks, and improves the safety and reliability of the unit operation by comprehensively assessing the state of the cooling pipe when the condenser is half-side in operation of the nuclear power plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0045] Figure 1 It is a flow chart of a method for evaluating the status of a half-side operation of a condenser in a nuclear power plant provided by an embodiment of the present invention;

[0046] Figure 2 It is a flow chart of a method for evaluating the status of a half-side operation of a condenser in a nuclear power plant provided by an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the velocity distribution in the throat and tube bundle of a typical condenser;

[0048] Figure 4 is a velocity field distribution diagram of a condenser tube bundle area provided by an embodiment of the present invention;

[0049] Figure 5 It is a schematic diagram of the electric power of a nuclear power unit corresponding to different seawater temperatures when the nuclear power unit is running at 75% Pn provided by an embodiment of the present invention;

[0050] Figure 6 It is a structural schematic diagram of a status assessment system for half-side operation of a condenser in a nuclear power plant provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] At present, there have been many condenser titanium tube leakages in the operating units of various nuclear power plants. The cause of these accidents is the fatigue fracture of the titanium tube caused by high-speed steam flow excitation. The fracture point is in the middle of the support plate tube sheet. The crack develops in a circumferential direction and is accompanied by friction on the outside of the tube wall. Therefore, the over-large design span of the condenser titanium tube support plate is an important reason for fluid excitation. Based on this, the present invention provides a state assessment method for the half-side operation of a condenser in a nuclear power plant. The method uses the span of the titanium tube support plate when the condenser half-side is running as the basis for assessment, so as to achieve a comprehensive assessment of the operating state of the condenser half-side, avoid risks, and improve the safety of unit operation.

[0053] refer to Figure 1 , which is a flow chart of a preferred embodiment of a state assessment method for half-side operation of a nuclear power plant condenser provided by the present invention.

[0054] Specifically, Figure 1 As shown, the state assessment method for the half-side operation of the condenser of the nuclear power plant includes the following steps:

[0055] Step S101, based on the steam flow excitation model of the condenser cooling pipe, calculate the standard span of the condenser when half of the condenser is in operation.

[0056] In some embodiments, the steam flow excitation model of the condenser cooling tube uses the speed of sound as a parameter, combined with the actual half-side operating condition parameters of the nuclear power plant condenser, to complete the calculation of the standard span of the support plate when the condenser half is running.

[0057] Specifically, based on the steam flow excitation model of the condenser cooling pipe, calculating the standard span when the condenser is half-side in operation includes: calculating the maximum deflection of the cooling pipe based on the steam flow excitation model of the condenser cooling pipe; calculating the standard span when the condenser is half-side in operation based on the value condition of the maximum deflection of the cooling pipe.

[0058] The force of the condenser cooling tube vibration is generated by the drag of the steam flow. The amplitude of the cooling tube increases with the increase of the steam flow speed. The maximum deflection (i.e. amplitude) of the cooling tube is Y m Keeping it within 1 / 4 of the cooling pipe arrangement bridge span can prevent the risk of steam flow vibration of the cooling pipe. Among them, the maximum deflection Y of the cooling pipe m It can be calculated by the following formula:

[0059]

[0060] (1) In the formula, Y m is the maximum deflection of the cooling pipe, m; L u is the support plate span (i.e. standard span), m; d0 is the cooling pipe diameter, m; ρ is the steam density corresponding to the turbine back pressure, kg·m -3 ; V s is the steam velocity, m·s -1 ; E is the elastic modulus of the cooling tube material, N·m -2 ; I is the moment of inertia of the cooling pipe section, m 4 It should be noted that the steam velocity in (1) is usually the steam velocity at the throat of the condenser, which is also commonly referred to as the turbine exhaust velocity. When the type of cooling pipe is determined, the greater the steam velocity, the lower the calculated support plate span.

[0061] Taking a certain unit as an example, the actual bridge distance of the cooling pipe of the condenser is 0.0056m, and the maximum deflection is less than or equal to 1 / 3 of the actual bridge distance. Therefore, formula (1) can be used to obtain:

[0062]

[0063] The support plate span can be calculated by formula (2), and then the calculated value can be compared with the actual value to determine whether the condenser meets the power operation requirements.

[0064] Step S102: judging whether the condenser meets the power operation requirement based on the standard span.

[0065] In some embodiments, judging whether the condenser meets the power operation requirements based on the standard span includes: obtaining the actual span; comparing the standard span with the actual span; if the standard span is greater than or equal to the actual span, judging that the condenser does not meet the power operation requirements; if the standard span is less than the actual span, judging that the condenser meets the power operation requirements.

[0066] Specifically, in step S101, after the standard span is calculated by formula (2), the standard span is compared with the actual span of the cooling pipe; if the standard span is greater than the actual span, it is determined that the condenser does not meet the power operation requirements; if the standard span is less than the actual span, it is determined that the condenser meets the power operation requirements. Furthermore, after the span verification of the half-side operation of the condenser is performed, in order to further evaluate the operating status of the half-side of the condenser, it is also necessary to perform failure assessment and risk assessment on the condenser, that is, when the power operation is not met, a risk assessment is required, and when the power operation is met, a failure assessment is required. Specifically, as shown in step S103 and step S104.

[0067] Step S103: If yes, perform failure assessment.

[0068] In some embodiments, if yes, performing failure assessment includes: if the condenser meets the power operation requirements, then calculating the fatigue critical span, the impact critical span and the shear critical span of the cooling tube; performing failure assessment based on the fatigue critical span, the impact critical span and the shear critical span. Among them, performing failure assessment based on the fatigue critical span, the impact critical span and the shear critical span includes: judging whether the fatigue critical span, the impact critical span and the shear critical span are all greater than the actual value; if yes, judging that the half side of the condenser can operate at full power; if not, judging that the half side of the condenser cannot operate at full power.

[0069] Specifically, the fatigue critical span of the cooling pipe is calculated as follows:

[0070] If the static deflection caused by the deadweight of the cooling pipe is ignored, the following relationship exists between the dynamic stress and static stress of the cooling pipe during vibration:

[0071] σ d =βσ m (3).

[0072] In the formula, σ d is the dynamic stress of the cooling pipe when it vibrates; σ m The exciting force F L The static stress generated when the static load acts on the cooling pipe; β is the dynamic amplification factor.

[0073]

[0074] In the formula, F L It is the lift generated when the fluid sweeps across the cooling pipe, which is equivalent to the load; C L is the lift coefficient; γ is the density of the fluid, N·m -3 .

[0075] If the alternating strain on the cooling pipe is less than 2 / 3 of the allowable endurance limit of the cooling pipe material, the cooling pipe material can be used for a long time without damage. Based on this condition, the fatigue critical span of the cooling pipe can be obtained as:

[0076]

[0077] (5) In the formula, L u1 is the fatigue critical span of the cooling tube, m; σ t D is the allowable endurance limit of the cooling pipe material at the temperature, N·m- 3 , V c1 is the critical fatigue speed, m / s; d i is the inner diameter of the cooling pipe, m.

[0078] When the cooling pipe vibrates, the relationship between its dynamic deflection and static deflection is as follows:

[0079] Y d =βY m (6).

[0080] Where Y d Y is the deflection of the cooling pipe when it vibrates; m is the exciting force F L The deflection caused by static load acting on the cooling pipe.

[0081] The critical span of the cooling pipe collision and friction is calculated as follows:

[0082] If the dynamic deflection of the cooling pipe is 1 / 2 of the bridge span, the cooling pipe will collide. From this, the maximum allowable span, that is, the critical span of collision and wear, can be derived as follows:

[0083]

[0084] Where V c2 is the critical collision velocity, m / s.

[0085] The shear critical span of the cooling pipe is calculated as follows:

[0086] Taking shear stress and wear effect as limiting conditions, the maximum allowable span is called the shear critical span L u3 , which can be expressed as:

[0087]

[0088] Where V c3 is the critical shear velocity, m / s; Km represents the wear coefficient.

[0089] After respectively calculating the fatigue critical span, the impact critical span and the shear critical span of the cooling pipe by the above formula (5), formula (7) and formula (8), the actual span of the support plate is compared with the fatigue critical span, the impact critical span and the shear critical span. If the actual span of the support plate is smaller than the fatigue critical span, the impact critical span and the shear critical span, then no vibration damage will occur regardless of the excitation frequency. Therefore, the condenser half side can operate at full power. Otherwise, the condenser half side cannot operate at full power. At this time, if it is determined that the condenser half side cannot operate at full power, a risk assessment is performed, that is, step S104 is continued.

[0090] Step S104: If not, perform risk assessment.

[0091] In some implementations, when the condenser cannot operate at full power, a risk assessment is required, which specifically includes: calculating the critical flow rate of the cooling pipe under a certain power platform; and performing risk assessment based on the critical flow rate of the cooling pipe. Among them, the risk assessment based on the critical flow rate of the cooling pipe includes: comparing the critical flow rate of the cooling pipe with the throat outlet flow rate of the condenser; if the critical flow rate of the cooling pipe is greater than the throat outlet flow rate of the condenser, the condenser is judged to be in a safe state; if the critical flow rate of the cooling pipe is less than the throat outlet flow rate of the condenser, the condenser is judged to be in a risky state, and the power reduction operation is continued.

[0092] Specifically, when the flow velocity reaches a certain value (critical velocity), the work done by the elastic force of the liquid on the pipe system is greater than the work consumed by the damping effect of the pipe system, and the response amplitude of the pipe will increase rapidly. Even a small increase in the flow velocity will cause a sudden increase in the amplitude of the pipe, so that the pipe collides with the pipe it believes in and is destroyed. Among them, the critical flow velocity can be calculated by the following formula:

[0093]

[0094] Where: V c is the critical flow velocity, m·s -1 ; K c is the coefficient, i.e., the fluid elastic instability coefficient; m is the mass per unit length of the full water heat exchange tube, kg·m -1 ; f is the first-order natural frequency of the cooling tube, Hz; δ is the logarithmic attenuation coefficient, which can be taken as 0.036.

[0095] K cIt is usually determined by experiments, and its value is related to the mass damping parameters and the arrangement of the cooling tubes. Different from conventional shell and tube heat exchangers, the proportions of steam entering the top, side and bottom of a typical condenser tube bundle are 40%, 40% and 20% respectively, and there is a large steam flow unevenness, such as Figure 3 The two-dimensional flow field distribution of the half-side operating condition of the condenser of a certain unit in a nuclear power plant is shown in Figure 4 The velocity of the steam inlet channel in the middle of the condenser tube bundle is the largest, which is about V at the throat outlet. a The velocity is 1.5 times of the velocity, and the velocity near the tube bundle is reduced by about 1.4 times. Different condenser tube bundles have large inlet steam flow rates with large inlet steam unevenness, so the condenser throat outlet velocity V is often used in engineering. a The flow rate replaces the steam inlet flow rate of the tube bundle.

[0096] In the embodiment of the present invention, the condenser throat outlet flow velocity V a As a benchmark, considering the non-uniformity of flow velocity, we can get:

[0097]

[0098] (10) where m is the mass per unit length of the full water cooling pipe, kg / m; v is the steam specific volume, m 3 / kg.

[0099] Then we can get the risk factor: V a / V c .

[0100] If V c Greater than V a (i.e. V a / V c <1), it can be determined that the titanium tube is in a safe state, that is, it can be determined that the condenser is currently in a safe operating state.

[0101] Furthermore, if the critical flow rate of the cooling pipe is greater than the throat outlet flow rate of the condenser, determining that the condenser is in a safe state includes: obtaining the amplitude of the cooling pipe; determining whether the cooling pipe is rubbed based on the amplitude of the cooling pipe; if so, performing a power reduction operation; if not, determining that the condenser is in a safe operating state.

[0102] Specifically, the amplitude of the cooling pipe calculated by formula (1) is compared with the actual bridge distance. If the amplitude of the cooling pipe is less than or equal to 1 / 3 of the actual bridge distance, the cooling pipe will not collide and rub. Therefore, the safe operation status of the condenser can be determined.

[0103] In a specific embodiment, Figure 2As shown, first, the standard span is calculated, and the operating span of the half side of the condenser is checked according to the standard span. If it meets the requirements, the impact, fatigue and shear failure assessments are performed. If not, the risk assessment is performed directly. When the impact, fatigue and shear failure assessments meet the requirements, it can be determined that the half side of the condenser can operate at full power. Otherwise, it cannot operate at full power. At this time, the risk assessment is continued. When performing the risk assessment, if the critical flow rate is greater than the condenser throat outlet velocity, the condenser is determined to be in a safe operating state. Otherwise, it can be determined that the current operating state of the condenser is unsafe. At this time, the operating power needs to be reduced. The reduction operation of the operating power can adopt a general method. When the condenser risk assessment passes, the amplitude assessment can be further performed. If the amplitude assessment also passes, the current operating power of the unit can be directly determined, and the condenser operation can be controlled based on the current operating power. The current operating power of the unit can be determined by the usual method. If the amplitude assessment fails, the power reduction operation is performed.

[0104] The present invention adopts double verification of risk coefficient and amplitude of cooling tube to monitor and evaluate the operation status of condenser cooling tube, and determines the specific nuclear power operation in combination with the actual status of nuclear power plant equipment and core control strategy.

[0105] The state evaluation method for half-side operation of a nuclear power plant condenser of the present invention uses the speed of sound as a conservative value and is relatively reliable. The span is the smallest in the winter half-row operation condition, and the smallest span should be used for the condenser design. The details are shown in Table 1.

[0106] Table 1 Design span of cooling pipes under different working conditions of a pressurized water reactor nuclear power project

[0107] Working conditions Rated winter Winter half column Exhaust flow kg / s 838.20 847.16 843.85 Exhaust area <![CDATA[m 2 ]]> 227.07 227.07 113.53 Exhaust pressure kPa 5.78 3.37 6.31 Blocking backpressure kPa 4.17 4.21 8.75 The span of the present invention mm 715 818 699

[0108] Taking the actual steam flow rate under different working conditions as input, the critical span of condenser failure under three vibration mechanisms is shown in Table 2.

[0109] Table 2 Failure mode span of cooling pipes under different working conditions of a pressurized water reactor nuclear power project

[0110] project Rated operating conditions Winter conditions Winter half column Fatigue span / mm 1245.23 955.17 644.55 Collision span / mm 755.78 661.93 543.75 Shear span / mm 5103.50 3002.83 1367.37

[0111] The minimum span value of the collision mechanism is 544mm, which is the most conservative. It is lower than the actual span value of the support plate of the nuclear power plant, which is 559mm. This shows that if the condenser is operated on this platform, there may be a risk of collision and friction, which may cause the titanium tube to break. The specific operating power platform needs to be carefully identified.

[0112] The risk factor and amplitude of the condenser cooling tube at different power platforms and different seawater temperatures are shown in Table 3 below.

[0113] Table 3 Risk coefficients under different thermal power platforms

[0114]

[0115]

[0116] From Table 3, we can see that at 75% P n When the power platform is reached, the risk coefficient of the cooling pipe is less than 1, and the amplitude of the cooling pipe is less than the limit value of 1.87mm (1 / 3 of the bridge distance of 5.6mm). n The condenser cooling tubes are safe when the nuclear power platform is in operation. Combined with the core control strategy requirements and the conservative decision-making principle of the nuclear power plant, the nuclear power plant should be controlled at 75% P n Nuclear power platform operation.

[0117] The fitting result is 75% P n The corresponding electrical power of the nuclear power platform at different seawater temperatures is shown in the Appendix Figure 5 When the unit condenser needs to be operated at half side, the unit electric power control can be carried out according to this curve. Under the corresponding seawater temperature, it should not exceed Figure 5 The electric power value corresponding to the middle curve. Figure 5 A quadratic curve fitting function is also provided for easy calculation.

[0118] The present invention also provides a status assessment system for half-side operation of a nuclear power plant condenser, which can be used to implement the status assessment method for half-side operation of a nuclear power plant condenser disclosed in an embodiment of the present invention.

[0119] Specifically, Figure 6 As shown, the status assessment system for the half-side operation of the condenser of the nuclear power plant includes:

[0120] A calculation unit 601 calculates a standard span of a condenser when half of the condenser is in operation based on a steam flow excitation model of a condenser cooling pipe;

[0121] A judging unit 602, used to judge whether the condenser meets the operation requirements based on the standard span;

[0122] A failure assessment unit 603 is used to perform failure assessment when the condenser meets the power operation requirement;

[0123] The risk assessment unit 604 is used to perform risk assessment when the condenser does not meet the power operation requirement.

[0124] Furthermore, the nuclear power plant condenser half-side operation status assessment system also includes:

[0125] An amplitude evaluation unit 605 and a power reduction unit 606. The amplitude evaluation unit 605 is used to evaluate the safe operation state based on the amplitude of the cooling pipe. The power reduction unit 606 is used to perform a power reduction operation.

[0126] The present invention monitors and evaluates the operating status of the condenser cooling tube under each power platform based on the dual verification of the risk coefficient and the amplitude, and combines the nuclear power plant core control strategy to determine the specific power platform for safe operation of the condenser, breaking through 60% P under the half-side operation condition of the condenser. n Restrictions can generate higher economic benefits while ensuring safety.

[0127] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0128] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0129] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0130] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot limit the scope of protection of the present invention. 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 method for evaluating the status of a half-side operation of a condenser in a nuclear power plant, characterized in that: The following steps are involved: Based on the steam flow excitation model of condenser cooling tube, the standard span of the condenser half-side operation is calculated; The method of calculating the standard span of the condenser when half of the condenser is in operation based on the steam flow excitation model of the condenser cooling pipe comprises: calculating the maximum deflection of the cooling pipe based on the steam flow excitation model of the condenser cooling pipe; calculating the standard span of the condenser when half of the condenser is in operation based on the value condition of the maximum deflection of the cooling pipe; judging whether the condenser meets the power operation requirement based on the standard span; If yes, conduct failure assessment; If so, performing failure assessment includes: if the condenser meets the power operation requirements, calculating the fatigue critical span, the collision critical span and the shear critical span of the cooling tube; performing failure assessment based on the fatigue critical span, the collision critical span and the shear critical span; The failure assessment based on the fatigue critical span, the impact critical span and the shear critical span includes: judging whether the fatigue critical span, the impact critical span and the shear critical span are all greater than actual values; if so, judging that the condenser half side can operate at full power; if not, judging that the condenser half side cannot operate at full power; If not, conduct a risk assessment; The risk assessment comprises: calculating the critical flow rate of the cooling pipe; and performing risk assessment according to the critical flow rate of the cooling pipe; The risk assessment based on the critical flow velocity of the cooling pipe includes: comparing the critical flow velocity of the cooling pipe with the throat outlet flow velocity of the condenser; if the critical flow velocity of the cooling pipe is greater than the throat outlet flow velocity of the condenser, it is judged that the condenser is in a safe state; if the critical flow velocity of the cooling pipe is less than the throat outlet flow velocity of the condenser, it is judged that the condenser is in a risky state, and a power reduction operation is performed.

2. The method for evaluating the status of a half-side operation of a condenser in a nuclear power plant according to claim 1, characterized in that: The judging whether the condenser meets the power operation requirement based on the standard span includes: Get the actual span; comparing the standard span with the actual span; If the standard span is greater than or equal to the actual span, the condenser is judged not to meet the power operation requirement; If the standard span is smaller than the actual span, it is determined that the condenser meets the power operation requirement.

3. The method for evaluating the status of a half-side operation of a condenser in a nuclear power plant according to claim 1, characterized in that: The method further comprises: If it is determined that the condenser half cannot be operated at full power, a risk assessment is performed.

4. The method for evaluating the status of a half-side operation of a condenser in a nuclear power plant according to claim 1, characterized in that: If the critical flow rate of the cooling pipe is greater than the throat outlet flow rate of the condenser, then judging that the condenser is in a safe state comprises: Obtaining the amplitude of the cooling pipe; Determining whether the cooling pipe is rubbed according to the amplitude of the cooling pipe; If yes, then perform power reduction operation; If not, it is determined that the condenser is in a safe operating state.

5. A nuclear power plant condenser half-side operation status assessment system, characterized in that: include: A calculation unit, based on the steam flow excitation model of the condenser cooling pipe, calculates the standard span when the condenser is in half-side operation; The method of calculating the standard span of the condenser when half of the condenser is in operation based on the steam flow excitation model of the condenser cooling pipe comprises: calculating the maximum deflection of the cooling pipe based on the steam flow excitation model of the condenser cooling pipe; calculating the standard span of the condenser when half of the condenser is in operation based on the value condition of the maximum deflection of the cooling pipe; A judging unit, configured to judge whether the condenser meets the operation requirements based on the standard span; A failure assessment unit is used to perform failure assessment when the condenser meets the power operation requirements; the failure assessment includes: if the condenser meets the power operation requirements, then calculate the fatigue critical span, the impact critical span and the shear critical span of the cooling tube; perform failure assessment based on the fatigue critical span, the impact critical span and the shear critical span; the failure assessment based on the fatigue critical span, the impact critical span and the shear critical span includes: determine whether the fatigue critical span, the impact critical span and the shear critical span are all greater than actual values; if so, determine that the condenser half side can operate at full power; if not, determine that the condenser half side cannot operate at full power; A risk assessment unit, used for performing risk assessment when the condenser does not meet the power operation requirement; The risk assessment comprises: calculating the critical flow rate of the cooling pipe; and performing risk assessment according to the critical flow rate of the cooling pipe; The risk assessment based on the critical flow velocity of the cooling pipe includes: comparing the critical flow velocity of the cooling pipe with the throat outlet flow velocity of the condenser; if the critical flow velocity of the cooling pipe is greater than the throat outlet flow velocity of the condenser, it is judged that the condenser is in a safe state; if the critical flow velocity of the cooling pipe is less than the throat outlet flow velocity of the condenser, it is judged that the condenser is in a risky state, and a power reduction operation is performed.

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