KR20080020254A - An on-line core protection system using 4 channel cea position signals and the method thereof - Google Patents

Abstract

An on-line core protection system using 4 channel CEA(Control Element Assembly) position signals and a method thereof are provided to convert a signal of a control element position detector of one channel into a digital signal and perform a validity test with an input signal conversion device, thereby simplifying signal processing. An on-line core protection system using 4 channel CEA position signals includes four control element position detectors, an input signal conversion device(120), a control device(130), and a display device(140). The four control element position detectors independently detect control element positions by dividing an individual CEA into four channels. The input signal conversion device receives a system input signal by channels including CEA position signals from the four control element position detectors and converts the signal into a digital signal. The control device calculates a realtime calculation result value of core driving information including a nucleate boiling aberration rate and a line output density factor based on the digital signal inputted from the input signal conversion device. The display device receives the calculation result value calculated from the control device and displays the calculation result value in real time.

Description

Online core protection system using 4 channel control rod assembly position signal and its method {An On-line Core Protection System using 4 Channel CEA Position Signals and the method

1 is a block diagram showing a schematic configuration of a conventional core protection system.

Figure 2 shows a schematic configuration of a control rod assembly provided with four control rod position detectors per individual control rod assembly according to the present invention.

3 is a block diagram showing a schematic configuration of a core protection system using four control rod position detectors per individual control rod assembly according to the present invention;

4 is a block diagram showing a schematic configuration of the control device shown in FIG.

5 is a module-specific link diagram for the core protection algorithm for each channel of the central processing unit shown in FIG.

6 is a flow chart showing a schematic flow of a core protection method using four control rod position detectors per individual control rod assembly according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: control rod assembly (CEA) 20: control rod position detector-A (RSPT-A)

30: control rod position detector-B (RSPT-B) 40: control rod position detector-C (RSPT-C)

50: control rod position detector-D (RSPT-D)

100, 200, 300, 400: control rod assembly position input signal

110, 210, 310, 410: other grid input signals

120, 220, 320, 420: input signal converter

130, 230, 330, 430: control device 130-1: central processing unit

130-2: I / O device 131: coolant flow calculation module

132: control rod position calculation module 133: operation variable calculation module

134: output distribution synthesis module 135: critical heat flux calculation module

136: trip module

140, 240, 340, 440: display device

The present invention relates to an online core protection system and method using a four-channel control rod assembly position signal. More specifically, four independent control rod position signals (RSPT-A, RSPT-B, RSPT-C, RSPT-D) are detected by providing four control rod position detectors for generating the control rod assembly position signals for each control rod assembly. Therefore, the present invention relates to an online core protection system and a method using a four-channel control rod assembly position signal capable of stable, reliable, and simple core protection by independently processing four channels.

In general, nuclear reactors generate heat using nuclear fission reactions of uranium fuel. The reactor is divided into light water reactor and heavy water reactor according to the type of cooling water used to lower the temperature of high temperature fuel. The water reactor maintains a high temperature-high pressure state to maximize heat transfer in the fuel rods and steam generators and to prevent boiling of the cooling water. In addition, the heat transfer method between the nuclear fuel rods and the cooling water of the water reactor is used a convective heat transfer or a nuclear boiling heat transfer method.

According to the heat transfer characteristics between the heating surface and the fluid, when the heat transfer is outside the nuclear boiling heat transfer region, the heat transfer efficiency is rapidly deteriorated, so that the local temperature of the hard water reactor heating surface is greatly increased. In other words, if the heat transfer between the fuel rod and the coolant is not good, there is a risk that the fuel melting or the fuel rod may be locally damaged.

Therefore, the reactor monitoring device is designed to keep fuel rod maximum local power density (LPD) and Departure from Nucleate Boiling (DNB) in the design of fuel in order to maintain the damage caused by fuel melting or fuel rod damage. The limit value for the monitoring should be set and monitored. The linear power density limit is defined as the limit of the linear power density of the fuel rod resulting in fuel melting. The nuclear boiling deviation limit is defined as the limit of the nuclear boiling heat flux or the critical heat flux of the fuel rod where the nuclear boiling deviation occurs. do. Here, the critical heat flux is calculated by an empirical formula using a given local core condition, and the ratio of the actual measured heat flux is defined as a nuclear boiling deviation rate (DNBR).

The trial run of Yeonggwang No. 3 and 4 and the cause of channel trip or reactor shut down of many core protection operators during normal operation were caused by the failure of transmission and reception between control rod position detector and control rod operation. The reason is that if one of the two control rod operators (CEAC1, CEAC2) generates a false signal due to component failure, the core protection calculator (CPC) channel trip or, furthermore, the reactor shutdown by the CPC. Because it is generated. As described above, the existing core protection system (CPCS) has four core protection operators and two control rod operators connected to each other in hardware. Therefore, a failure of one control rod affects four core protection operators and causes unnecessary reactor shutdown. Have

On the other hand, Korean Patent Publication No. 2004-0099884 discloses a real-time thermal protector (ITOP; Integrated Thermal On-line) (1), Maintenance Test Bench (MTP) in order to solve the problems of the conventional control rod position detector as described above. Two Reed Switch Position Transmitter (RSPT) signals consisting of a panel (2), an operator module (OM), and a control rod position display (CEAPD) (4). A four-channel integrated real-time reactor thermal protection system is shown in software connection (see Figure 1). The real-time thermal protector 1 integrates the functions of a core protection calculator (CPC) and a control element assembly (CEAC) into one core operation such as the nuclear boiling deviation rate (DNBR) and the line power density (LPD). Central processing unit (CPU) that calculates parameters in real time, auxiliary operation module that performs calculations for operator linkage functions such as core flow rate and core output correction and core nuclear boiling deviation rate operation limit monitoring. It consists of common and I / O modules that transmit the calculated results to the maintenance test bench (2), the operator module (3) and the plant alarm system.

The maintenance test bench 2 and the operator module 3 receive the core operation information calculated in real time in each channel of the integrated real-time thermal protector 1 through the intra channel network, thereby allowing the operator to receive the core operation information. It is a device that can observe in real time. In addition, the control rod position display device is a device for displaying the control rod position information received from the maintenance test bench (2) to the operator as a picture information indicating the state of the control rod insertion.

However, such an integrated real-time reactor thermal protection system requires a separate device such as a control rod assembly (CEA) input / output module and has a disadvantage in that a device error is likely due to a complicated signal transmission system. In addition, by using two control rod position detector signals in four channels in common by selection logic, one control rod assembly position signal error can affect all four channels, which is unnecessary due to lack of complete system independence. The possibility of a reactor shutdown still exists. In addition, the target CEA set A (RSPT1) is separated from the CEA set 1 (RSPT-1) and CEA set 2 (RSPT-2) of FIG. However, the need for additional transmission of control rod position signals belonging to the quadrant, such as target CEA set D (RSPT2), increases the likelihood of control rod position signal transmission errors.

Therefore, there is a need for a reactor blocking system that is reliable and stable and has a simple structure.

An object of the present invention is to provide a stable control system by providing four control rod position detectors for each individual control rod assembly, by using a system that can use independent control rod position signals in four channels. The present invention provides an online core protection system and method using a four-channel control rod assembly position signal capable of more reliable and reliable core protection.

In order to achieve the above object, the online core protection system using the four-channel control rod assembly position signal of the present invention comprises: four control rod position detectors each divided into four channels per individual control rod assembly and independently detecting the control rod position; An input signal conversion device for receiving a system input signal for each channel including the control rod assembly position input signals from the four control rod position detectors and converting the system input signals into digital signals; A control device for calculating a real-time calculation result value of core operation information including a nuclear boiling deviation rate and a line power density factor based on the digital signal input from the input signal conversion device; And a display device receiving the calculation result value calculated by the control device and displaying the calculated result in real time.

In order to achieve the above object, the control device of the present invention includes a central processing unit for calculating the core operation information in real time based on a signal input divided into four channels per individual control rod assembly; And an input / output device for inputting and outputting the input signal and the core operation information calculation result value.

In order to achieve the above object, the online core protection method using the four-channel control rod assembly position signal of the present invention uses four control rod position detectors per individual control rod assembly to enable the use of position signals of independent control rod assemblies in four channels. Detecting the position of the control rod; Generating a system input signal for each channel including the control rod assembly position input signals respectively detected from the four control rod position detectors; Converting the generated system input signal into a digital signal; Calculating a real-time calculation result value of core operation information including a nuclear boiling deviation rate and a line power density factor of the core based on the converted digital signal; Receiving the calculated calculation result and displaying in real time; And generating a reactor stop signal when the calculated result is in violation of the normal operating range.

At present, the core protection system uses a control rod position indicator having a high precision and reliability that detects the position of the control rod and sends a position signal to the safety system. The applicant of the present invention discloses a control rod position detector according to Korean Patent No. 0600977. We have been registered for the structure.

Hereinafter, an online core protection system using the four-channel control rod assembly position signal of the present invention having the control rod position detector will be described in detail with reference to the accompanying drawings.

2 is a view showing a schematic configuration of a control rod assembly provided with a four-channel control rod position detector according to the present invention.

As shown in the figure, the individual control rod assemblies 10 are individually provided with four control rod position detectors (RSPT-A, RSPT-B, RSPT-C, RSPT-D) 20, 30, 40, 50. An independent control rod position signal is detected for each channel, and each of these signals is input to four channels of the online core protection system using the four-channel control rod assembly position signal of the present invention.

3 is a block diagram showing a schematic configuration of a core protection system using a four-channel control rod position detector according to the present invention.

As shown in the figure, the online core protection system using the four-channel control rod assembly position signal of the present invention comprises an input signal converter 120, the control device 130, the display device 140.

Hereinafter, only a structure and a signal processing method of a single channel (for example, channel A) of the four channels of the present invention will be described, and the remaining channels (channels B, C, and D) have the same structure as that of the single channel; Since the signal processing method is used, the redundant description is omitted.

The input signal conversion device 120 is a position signal belonging to the corresponding channel and other corresponding channel among the position signal of the measured control rod assembly from the four control rod position detector (20, 30, 40, 50) for each control rod assembly 10 It is a device that receives each system input signal and converts it into digital signal. The input signal converter 120 receives the system input signals 100 and 110 including the control rod assembly position input signal, which is an analog signal, and converts them into digital signals. The control rod assembly position input signal is a position signal transmitted to each channel (channel A, channel B, channel C, channel D) from four control rod position detectors 20, 30, 40, and 50 for each control rod assembly 10. . In other words, in the case of channel A of the online core protection system using the four-channel control rod assembly position signal of the present invention, the position input of the control rod position detectors 20, 30, 40, and 50 corresponding to channel A per control rod assembly 10 is provided. The signal 100 is independently transmitted only to the input signal conversion device 120 of the channel A. The system input signal includes a control rod assembly position input signal, a coolant flow rate, a core inlet temperature, a core outlet temperature, a system pressure, and an external nuclear instrument signal.

In addition, the input signal converter 120 performs a validity test on the digital signal. The validity test is a test for determining whether the digital signal is included within a predetermined predetermined criterion. That is, the input signal converter 120 may convert a converted error of the converted digital signal according to a database in which a reference signal corresponding to each core protection system stored in a memory (not shown) of the central processing unit 130-1 is stored. Check it. In addition, the core protection system using the four-channel control rod assembly of the present invention uses a method of immediately converting the analog signals (20, 30, 40, 50) of the four control rod position detector per individual control rod assembly (10) Therefore, the signal transmission system is simpler and less likely to cause mechanical error than the core protection system that converts signals in the existing central processing unit.

The control device 130 calculates a real-time calculation result of core operation information including a nuclear boiling deviation rate and a linear power density factor based on the digital signal input from the input signal conversion device 120. In other words, in the case of channel A of the online core protection system using the four-channel control rod assembly position signal of the present invention, the input signal conversion device 120 of the control rod position detector 20 corresponding to the channel A per control rod assembly 10 is included. The digital signal is independently transmitted only to the controller 130 of channel A.

The display device 140 is a device for observing core driving information received from the control device 130 in real time and visually sensing the driving information.

Specifically, in the case of channel A, an analog type grid input signal including an individual control rod assembly position signal (RSPT-A) 20 belonging thereto is transmitted to the input signal converter 120 and converted into a digital signal. The control device 130 receives the converted digital signal and calculates a nuclear boiling deviation rate and a line power density. The calculated value is transferred to a display device to be a display. 4 is a block diagram showing a schematic configuration of the control device shown in FIG.

As shown in the figure, the control device 130 is composed of a central processing unit (130-1) and input and output device (130-2).

The central processing unit (130-1) is a device for calculating the core operation information in real time based on the input signal. That is, the central processing unit 130-1 calculates in real time the main core operation factors such as the nuclear boiling deviation rate and the line power density using the system input signals 100 and 110 including the control rod assembly position input signal.

Therefore, the central processing unit 130-1 simplifies the signal transmission system of the core protection system by directly receiving the digital signal without passing through another signal conversion device. The input / output device 130-2 receives the converted digital signal and transfers the converted digital signal to the central processing unit 130-1. The central operation processor 130-1 receives the core operation information calculation result and outputs the result in real time. Therefore, the core driving information calculated in real time in each channel is transmitted through the intra-channel network, so that the operator can observe the core driving information in real time.

FIG. 5 is a module-specific connection diagram for the core protection algorithm for each channel of the central processing unit shown in FIG. 4.

As shown in the figure, the central processing unit (130-1) is a coolant flow calculation module (COOLANT MODULE) 131, control rod position calculation module (CRPOS MODULE) 132, operation variable calculation module (CHECK MODULE) 133, an output distribution synthesis module (POWER MODULE) 134, a threshold heat flux calculation module (THERM MODULE) 135, and a trip module (TRIP MODULE) 136.

The coolant flow rate calculation module 131 calculates the core flow rate using the measured rotational speed (or frequency, current) of the coolant pump, and transmits the core flow rate to the output distribution composition module 134 and the critical heat flux calculation module 135, and the operating variables. The minimum nuclear boil-off rate is input from the calculation module 133 to perform correction calculation according to the core flow rate change, and transmit the modified minimum nuclear boil-off rate to the trip module 136.

The control rod position calculation module 132 processes the position (CEA Position) signal of the individual control rod assembly, calculates the nuclear boiling deviation rate and the linear power density penalty coefficient according to the position deviation, and transmits it to the operation variable calculation module 133 and the control rod position information. To the reactor output distribution synthesis module 134. That is, the control rod position calculation module 132 uses a signal belonging to the corresponding channel among the position signals of the control rod assembly measured from the position detectors 20, 30, 40, and 50, and determines the penalty coefficient and the position information of the control rod assembly (insertion or Degree of drawing) and transfers it to the operation variable calculation module 133 and the output distribution composition module 134, respectively.

The operating variable calculation module 133 calculates core output using various instrument input signals and core output distribution related information, and calculates the coolant flow rate and the line power density in real time by reflecting the operating conditions of the reactor, which changes frequently, and calculates the coolant flow rate. The module 131 and the trip module 136 are transmitted.

The output distribution synthesis module 134 is a core flow rate calculated by the coolant flow rate calculation module 131, the position information of the control rod assembly calculated by the control rod position calculation module 132, and the ex-core nuclear instrument delivered by the operation variable calculation module 133. Synthesizing the axial output distribution of the core in real time using the signal and passing it to the critical heat flux calculation module 135 and the operating variable calculation module 133 to calculate the nuclear boiling deviation rate and line power density.

Therefore, since the output distribution synthesis module 134 uses the position of the control rod assembly calculated by the control rod position calculation module 132 of the corresponding channel, a separate control rod position signal for calculating the target control rod value is required as in the related art. Do not.

The critical heat flux calculation module 135 calculates the detailed nuclear boiling deviation rate by using the core flow rate calculated in the coolant flow rate calculation module 131 and the axial output distribution synthesized in the output distribution synthesis module 134. Is transmitted to the operation variable calculation module 133.

The trip module 136 determines whether the reactor stop signal and the auxiliary stop signal are generated by comparing the nuclear boiling deviation rate and the line power density value received from the coolant flow rate calculation module 131 and the operation variable calculation module with a preset safety limit value. do.

On the other hand, as shown in Figure 6 on-line core protection method using the four-channel control rod assembly position signal of the present invention divided into four channels per individual control rod assembly, each using four control rod position detector to detect the control rod position independently Detecting a control rod position, generating a system input signal for each channel including control rod assembly position input signals respectively detected from the four control rod position detectors, and converting the generated system input signal into a digital signal; And calculating a real-time calculation result of core operation information including a nuclear boiling deviation rate and a line power density factor of the core based on the converted digital signal, and receiving the calculated calculation result value in real time. And if the calculation result violates the normal operating range, It can be divided into generating the ground signal.

The system input signal may further include a step of converting an individual control rod assembly position input signal, a coolant flow rate, a core inlet temperature, a core outlet temperature, a system pressure, and an external nuclear instrument signal into a digital signal. In addition, after the step of converting the system input signal into a digital signal, a validity check step of transmitting only a valid signal by checking whether the digital signal is included within a predetermined predetermined criterion may be further added.

As described above, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

Core protection system using the four-channel control rod assembly of the present invention configured as described above, by having four control rod position detectors for each control rod assembly can detect the four independent control rod position signals to protect the core of the reactor stably. .

In addition, the input signal converting device converts the signal of the control rod position detector of the single channel into a digital signal and performs a validity check on it, thereby simplifying signal processing.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications belong to the appended claims.

Claims (7)

In the core protection system that integrates the functions of the core protection and control rods in software, calculates the nuclear boiling deviation rate (DNBR) and the linear power density (LPD) in real time, and generates the reactor stop signal in case of violation of the normal operating range. , Four control rod position detectors each divided into four channels per control rod assembly and independently detecting the control rod position; An input signal conversion device for receiving a system input signal for each channel including the control rod assembly position input signals from the four control rod position detectors and converting the system input signals into digital signals; A control device for calculating a real-time calculation result value of core operation information including a nuclear boiling deviation rate and a line power density factor based on the digital signal input from the input signal conversion device; A display device receiving the calculation result value calculated from the control device and displaying the calculated result value in real time; Online core protection system using a four-channel control rod assembly position signal, characterized in that comprising a. The method of claim 1, The control device, A central processing unit for calculating the core operation information in real time based on a signal input from the input signal conversion device; An input / output device for inputting / outputting the input signal and the core operation information calculation result value; Online core protection system using a four-channel control rod assembly position signal, characterized in that comprising a. The method of claim 1, The system input signal is, An online core protection system using a four-channel control rod assembly position signal comprising a control rod assembly position input signal, a coolant flow rate, a core inlet temperature, a core outlet temperature, a system pressure, and an external nuclear gauge signal. The method of claim 2, The central processing unit, Calculate the core flow rate and transmit it to the output distribution synthesis module and the critical heat flux calculation module, input the minimum nuclear boiling deviation rate value from the operation variable calculation module, and perform correction calculation to correct the minimum nuclear boiling deviation rate value modified by the trip module. Coolant flow rate calculation module for transmitting the; Process the position signal of individual control rod assembly, calculate the nuclear boiling deviation rate and linear power density penalty coefficient according to the position deviation, and transfer it to the operation variable calculation module (CHECK) and output the insertion or withdrawal position of the control assembly to the reactor output distribution synthesis module (POWER) Control rod position calculation module for transmitting to; Calculate core output by using instrument input signal and core output distribution related information, and calculate the boiling rate and line output density in real time by reflecting the operating conditions of the reactor, which changes frequently, and the coolant flow calculation module (COOLANT) and trip module (TRIP) An operating variable calculation module for transferring to); Core axial direction using the core flow rate calculated in the coolant flow calculation module (COOLANT), the position of the control rod assembly calculated in the control rod position calculation module (CRPOS), and the external nuclear instrument signal transmitted from the operation variable calculation module (CHECK). An output distribution synthesis module for synthesizing the output distribution in real time and passing it to a critical heat flux calculation module (THERM) and an operating variable calculation module (CHECK) to perform nuclear boiling deviation rate and line power density calculation; Using the core flow calculated in the coolant flow calculation module (COOLANT) and the axial output distribution synthesized in the power distribution synthesis module (POWER), the detailed nuclear boiling deviation rate calculation is performed and this value is transferred to the operation variable calculation module (CHECK). A critical heat flux calculation module; Trip that determines whether the reactor stop signal and the auxiliary stop signal are generated by comparing the nuclear boiling deviation and line power density values received from the coolant flow calculation module (COOLANT) and the operation variable calculation module (CHECK) with a preset safety limit value. module; On-line core protection system using a four-channel control rod assembly position signal comprising a. In the core protection method, which integrates the functions of the core protection and control rods in software, calculates the nuclear boiling deviation rate (DNBR) and the linear power density (LPD) in real time, and generates the reactor stop signal in case of violation of the normal operating range. , Detecting the control rod position using four control rod position detectors per individual control rod assembly to enable use of position signals of the independent control rod assemblies in the four channels; Generating a system input signal for each channel including the control rod assembly position input signals respectively detected from the four control rod position detectors; Converting the generated system input signal into a digital signal; Calculating a real-time calculation result value of core operation information including a nuclear boiling deviation rate and a line power density factor of the core based on the converted digital signal; Receiving the calculated calculation result and displaying in real time; Generating a reactor stop signal when the calculated result is in violation of the normal operating range; Online core protection method using a four-channel control rod assembly position signal, characterized in that comprising a. The method of claim 4, wherein The system input signal may include a control rod assembly position input signal, a coolant flow rate, a core inlet temperature, a core outlet temperature, a system pressure, and an off-core nuclear instrument signal. . The method according to claim 5 or 6, After converting the system input signal into a digital signal, And a feasibility test step of delivering only a valid signal by checking whether the digital signal is included in a predetermined predetermined criterion. The online core protection method using the four-channel control rod assembly position signal further comprises:

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