KR101034252B1 - Trouble detecting apparatus for RSPT and CPCS having the same, and trouble detecting method thereof - Google Patents

Abstract

A failure diagnosis apparatus for a control rod position detector, a core protection calculator system including the same, and a failure diagnosis method thereof are disclosed. In the fault diagnosis apparatus of the control rod position detector according to the present invention, the control rods belonging to the same subgroup are controlled to move together at the same position at the same time, and the fault diagnosis apparatus of the control rod position detector installed in pairs for each control rod, comprising: a core protection calculator; And a comparator for determining whether a difference of the signal value received from the control rod position detector is out of a set range, wherein the comparator is based on the control group position detector based on the subgroup when the difference of the received signal value is out of the set range. It is determined whether the signal received from the error signal due to the abnormality of the sensor, and if it is determined that the error signal, characterized in that for transmitting the failure information of the control rod position detector to the core protection calculator.

Control rod, control rod position detector, comparator, core protection calculator, reactor uninterrupted

Description

Trouble detecting apparatus for RSPT and CPCS having the same, and trouble detecting method

The present invention relates to a failure diagnosis apparatus for a control rod position detector, a core protection calculator system including the same, and a failure diagnosis method. More particularly, the reactor is unnecessarily stopped due to a malfunction or failure of a reed switch and power generation is stopped. The present invention relates to a failure diagnosis apparatus for a control rod position detector, a core protection calculator system including the same, and a method for diagnosing the failure of the control rod position detector, which can not only effectively prevent economic losses from occurring, but also apply to existing operating nuclear power plants.

Among the nuclear power plants that generate electric power using nuclear reaction of uranium, pressurized water reactor type nuclear power plants have two Control Element Assembly Calculators (CEAC) 4 and 4 as shown in FIG. 1 to protect the core of the reactor. A Core Protection Calculation System (CPCS) 3 having a neutralized Core Protection Calculator (CPC) 5 is provided.

Here, the input signals of the core protection operation machine (3) are signals from the Reed Switch Position Transmitter (RSPT) 2 installed in the control element drive mechanism (CEDM) 1. RSPT (2) is installed two per control rod and CPC (5) is composed of four channels.

In addition, the RSPT 2 is composed of an electrical circuit combining a plurality of reed switches and a plurality of resistors having a mechanical drive that can be opened and closed by a surrounding magnetic field, and FIG. 2 shows such an actual reed switch. Show the appearance of (21).

3 is a view showing a part of the control rod drive device. As can be seen in the drawing, when the control rod drive shaft on which the permanent magnets 22 are installed is moved up and down, the control rods close to the magnets among the reed switches 21 installed on the outer wall are closed, so that the configuration of the electric circuit changes. The electrical value (voltage) representing the position changes. Therefore, the malfunction or failure of the reed switch transmits incorrect control rod position information as shown in FIG. 4, and as a result, the reactor is unnecessarily stopped and power generation is stopped, resulting in huge economic losses as well as obstacles to stable operation of nuclear power plants. Becomes

In order to solve this problem, as well as the introduction of the quadruple RSPT sensor, as shown in FIG. 5, a number of improved RSPT (Presence US Pat. No. 6,380,734) having a presence sensor 210 in addition to the position sensor 28 is shown. An improvement of RSPT has been proposed. However, the fabrication and installation of the improved RSPT requires complex changes throughout the system, including installation space issues, additional wiring, and major changes to the hardware and software of the CPCS. The application is very difficult for nuclear power plants.

The present invention was devised to solve the above problems, and it is possible to effectively prevent the occurrence of enormous economic losses by unnecessarily stopping the reactor and stopping power generation due to malfunction or failure of the reed switch. It is an object of the present invention to provide a failure diagnosis apparatus for a control rod position detector, a core protection calculator system including the same, and a method for diagnosing the failure, which can be applied also to the operating nuclear power plant.

The fault diagnosis apparatus of the control rod position detector according to the present invention for achieving the above object is controlled so that the control rods belonging to the same subgroup are simultaneously moved to the same position, and the fault diagnosis apparatus of the control rod position detector installed in pairs for each control rod. A core protection calculator; And a comparator for determining whether a difference of the signal value received from the control rod position detector is out of a set range, wherein the comparator includes the control rod position based on the subgroup when the difference of the received signal value is out of the set range. It is determined whether the signal received from the detector is an erroneous signal due to an abnormality of the sensor, and if it is determined to be an erroneous signal, fault information of the control rod position detector is transmitted to the core protection calculator.

Here, the comparator is implemented to evaluate the error range for the control rods belonging to each subgroup.

In addition, the core protection calculator system having the core protection calculator preferably has normal information for each control rod position detector.

On the other hand, the fault diagnosis apparatus of the control rod position detector, the step of receiving a signal from each control rod position detector installed in pairs for each control rod; Determining whether a difference between the received signal values is within a set range; And outputting a failure signal for a corresponding control rod position detector when the difference between the received signal values is out of a set range.

Here, it is preferable that the said comparator judges the range within 1/2 of the resolution of the control rod position detector determined as the same position as an allowable error.

Core protection calculator system according to the present invention for achieving the above object, Core protection calculator; Control rod position detectors, which are controlled to move together in the same position to the same position at the same time, each pair of control rod position detector; And determining whether the difference between the signal value received from the control rod position detector is out of a set range, and when the difference of the received signal value is outside the set range, a signal received from the control rod position detector based on the subgroup is an abnormality of a sensor. It is characterized in that it comprises a fault diagnosis device of the control rod position detector for determining whether the error signal by the, and if it is determined to be an error signal to transmit the failure information of the control rod position detector to the core protection calculator.

As a result, the control rod position detector, the core protection calculator system including the same, and the method of diagnosing the failure thereof can effectively prevent the nuclear reactor from being unnecessarily stopped due to the malfunction or failure of the reed switch and the generation of electricity is stopped, resulting in huge economic losses. In addition, it can be applied to existing operating nuclear power plants.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention. However, the embodiments of the present invention described below are provided to enable those skilled in the art to more easily understand the present invention, and the scope of the present invention is not limited to the described embodiments.

6 is a diagram illustrating a core protection calculator system associated with a failure diagnosis apparatus for a control rod position detector according to the present invention. As shown, the failure diagnosis apparatus of the control rod position detector according to the present invention can be applied to a general core protection calculator system (CPCS).

As described above, the CPCS 3 has two CEACs 4, each CEAC 4 receiving a control rod position signal from the RSPT 2 and a control rod deviation penalty based on position deviations between control rods in the same group. Calculate and pass the penalty factor accordingly to the four CPCs 5.

The CPC 5 selects a larger value of the penalty factor values transmitted from the two CEACs 4 to calculate the Departure from Nucleate Boiling Ratio (DNBR). Therefore, the failure or malfunction of one channel of RSPT (2) increases the positional deviation between the control rods and transmits a large penalty factor from the CEAC (4) to the CPC (5), resulting in 2/4 logic of the CPC (5). It acts as a trip source to prevent the accident by mechanically protecting the reactor by the reactor, and according to this trip command, the reactor protection system of the Hubby shuts down the reactor trip switch gear (RTSG) to control the rod. This loss causes the control rods to fall, causing the reactor to shut down safely. In summary, even one RSPT failure in RSPT (2) can result in reactor failure. In actual power plants, there are many cases of uninterrupted reactors due to such failures, and as the number of operating years of nuclear power plants increases, the number of uninterrupted failures due to such failures will increase as the equipment ages. Figure 4 illustrates the output waveform of the RSPT measured in the event of an uninterrupted nuclear power plant accident occurred in the actual nuclear power plant. In order to prevent such an uninterrupted, it may be considered to install the quadruple RSPT, but there are technical and spatial problems caused by the installation.

The fault diagnosis device of the control rod position detector according to the present invention prevents uninterrupted stoppage due to a single failure of RSPT without quadrupling the RSPT in the currently operating nuclear power plant and the nuclear power plant to be constructed in the future, thereby securing stable operation capability of the power plant and improving operation rate. Make it work. To this end, the failure diagnosis apparatus for the control rod position detector according to the present invention may be implemented in a structure as shown in FIG. That is, as shown in the figure, a separate independent device that does not affect the configuration or operation of the existing CPCS 3 is configured to diagnose the failure of the RSPT 2 and provide the result to the CPC 5 as auxiliary information. do.

The control rods in the reactor are installed in a predetermined pattern (symmetry) for the safety of the reactor and are grouped together to move in a fixed operating mode. An example of distribution and subgrouping of the control rods may be displayed as shown in FIGS. 8 and 9, in which control rods belonging to the same subgroup in FIG. 9 are simultaneously controlled to move to the same position. Therefore, in the normal operation, since the position detector output signals of the control rods belonging to the same subgroup must be the same, the RSPT fault detection apparatus can be configured by using these operating characteristics.

10 is a flowchart illustrating a failure diagnosis method of a control rod position detector according to the present invention. With reference to the drawings will be described in detail the function and operation of the failure diagnosis device of the control rod position detector according to the present invention.

First, if a dual RSPT signal is input to the CPCS (3), a pair of RSPT signals are installed for each control rod using a safety class controller, and the difference between the two signal values is within a predetermined range of a predetermined range. Does not send a separate signal to the CPC (5). Note that the CPC 5 already detects this situation.

If the difference between the two signal values is out of a certain error range, the signal diagnosis algorithm is used to evaluate the signal health of the two signal values, and the four control rods that must be moved to the same subgroup in the operation mode of the control rod. When the error range is evaluated for the RSPT signals, it is possible to diagnose whether the RSPT signal outside the error range is a sound signal or a false signal due to a sensor error.

If it turns out to be a false signal, the RSPC fault information is informed to the CPC 5 and an alarm is generated to operate the reactor without stopping while the operator recognizes the fault.

Here, even when two normal signals within the error range are determined as a nuclear reactor abnormal signal or a sensor abnormal signal due to a failure or error of the detection device, the CPCS 3 already has its own normal information and thus ignores false signals from the detection device. Therefore, there is no possibility of malfunction or the like of the CPCS 3. The configuration of the determination method performed by the detection apparatus can be summarized as shown in FIG. 11.

The RSPT fault detection apparatus shown in FIG. 7 detects a fault through the above fault diagnosis method by using the characteristic of grouping four to five subgroups of control rods so that a nuclear reaction in a nuclear reactor occurs evenly. . The operation of the RSPT fault detection apparatus shown in FIG. 7 is as follows.

First, in FIG. 7, block 8 represents a circuit 12 which receives and compares signals of eight position detectors 10 and 11 for four control rod drive units 9 belonging to one subgroup. And control rod position signal processing block for another subgroup of the same type.

The outputs of the comparators of each subgroup are combined in the OR-logic unit 16, and when there is one or more subgroups with RSPT having a single fault, RSPT fault information 17 is sent to the CPC 5 and the screen 15 is displayed. The detailed information on the subgroup where the failure occurred is displayed. Comparator 12 having arithmetic function performs a failure diagnosis method as shown in FIG.

First, the position signals are read from four pairs (eight) position detectors attached to four control rod drive devices (S101). Then, a plurality of eight values are set as reference values to determine whether all values are within tolerance. Determine. Here, the magnitude of the tolerance corresponds to half of the resolution of the RSPT determined to be the same position. If all values are within the tolerance range, it is determined to be normal (S103). If any value is out of tolerance, the detector value paired with this value is compared with the reference value (S105). If it is determined that one of the two pairs has failed (S107) and outputs an RSPT fault signal (S109) and the paired value is also within tolerance, either the RSPT pair of the control rod has failed or the control rod has not moved. Do not output the signal.

As shown in FIG. 7, the fault diagnosis device for the control rod position detector according to the present invention does not violate the safety system design requirement because the RSPT signal used for protecting the reactor is input as it is without modification as installed in the existing CPCS. By evaluating the signal with a separate diagnostic device, it informs the CPC of the abnormality of the sensor in the form of an auxiliary signal, so that it is possible to effectively prevent the reactor uninterrupted due to a simple single sensor failure.

In addition, the present invention has an effect that can effectively prevent the occurrence of a sudden stop or sudden output deceleration of the nuclear power plant due to a single failure of the control rod position detector which is a problem in the currently operating nuclear power plant.

In addition, the present invention is particularly useful for the already installed and operating operating nuclear power plant because it is possible to install and operate much more efficiently than the solution such as the development and installation of the quadruple RSPT.

Although the above has been illustrated and described with respect to the preferred embodiments of the present invention, the present invention is not limited to the above-described specific embodiments, it is usually in the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Anyone skilled in the art can make various modifications, as well as such modifications are within the scope of the claims.

1 is a diagram illustrating the configuration and linkage of a general core protection calculator system.

2 is a view illustrating the actual appearance of the reed switch.

3 is a view illustrating the installation structure of the control rod drive shaft and the control rod position detector in the control rod drive device.

4 is a diagram showing an example of a control rod position error signal due to a malfunction of the control rod position detector.

5 is a view showing an example of a conventional improved control rod position detector.

6 is a diagram illustrating a core protection calculator system associated with a failure diagnosis device for a control rod position detector according to the present invention.

7 is a view illustrating a structure of a failure diagnosis apparatus for a control rod position detector according to the present invention.

8 illustrates the placement of control rods in a reactor.

9 is a diagram illustrating a subgroup arrangement of the control rods.

10 is a flowchart illustrating a failure diagnosis method of a control rod position detector according to the present invention.

11 is a table summarizing the fault detection procedure and operation of the control rod position detector.

Claims (6)

In the failure diagnosis apparatus of the control rod position detector which is controlled so that the control rods belonging to the same subgroup are moved to the same position at the same time, each pair of control rods, Comparators for determining whether the difference of the signal value received from the particular control rod position detector is out of the set range, The comparator compares the signals received from the control rod position detectors installed in the control rods belonging to the same subgroup when the difference in the signal value received from the specific control rod position detector is received from the specific control rod position detector. And determining whether the received signal is a false signal due to a sensor abnormality, and transmitting failure information of the control rod position detector to a core protection calculator when determining that the received signal is a false signal. The method of claim 1, And said comparator evaluates an error range for control rods belonging to each subgroup. The method of claim 1, The core protection calculator system having the core protection calculator has its own normal information about each control rod position detector. In the failure diagnosis method of the control rod position detector which is controlled so that the control rods belonging to the same subgroup move to the same position at the same time, each pair of control rods, (a) receiving a signal from a specific control rod position detector; (b) determining whether a difference between signal values received from the specific control rod position detector is within a set range; And (c) when the difference of the signal value received from the specific control rod position detector is out of the set range, by comparing the signals received from the control rod position detectors installed in the control rods belonging to the same subgroup, the specific control rod position detector Determining whether the signal received from the sensor is an error signal due to an abnormality of the sensor, and transmitting the failure information of the control rod position detector to the core protection calculator when the signal is determined to be an error signal; Failure diagnosis method of the control rod position detector comprising a. The method of claim 4, wherein In the step (b), the fault diagnosis method of the control rod position detector, characterized in that it determines within a range of 1/2 of the resolution of the control rod position detector determined to the same position as an allowable error. Core protection calculator; Control rod position detectors, which are controlled to move together in the same position to the same position at the same time, each pair of control rod position detector; And Determines whether the difference of the signal value received from the specific control rod position detector is out of the set range, and if the difference of the signal value received from the specific control rod position detector is out of the set range, the control rod position detector installed in the control rods belonging to the same subgroup Comparing the signals received from the signals, and determining whether the signal received from the specific control rod position detector is an erroneous signal due to an abnormality of the sensor, and transmitting fault information of the control rod position detector to the core protection calculator when it is determined to be an erroneous signal. Core protection calculator system comprising a failure diagnosis device of the control rod position detector.

Images