JP2501178B2 - Reactor safety protection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor safety protection device which detects the same state quantity of a nuclear reactor by four sensors to judge an abnormality and performs a protective operation when two operating means are activated.

[0002]

2. Description of the Related Art In a nuclear power plant, in order to ensure the safety of a nuclear reactor, a safety protection device is provided in order to prevent an abnormal transient state or the like from occurring. For example, in Japanese Patent Laid-Open No. 61-118801, a quadrupled sensor and a channel set signal processor (signal processing means) are connected in series, and each output signal of four channel set signal processors is input. 1 shows a reactor safety protection device with two logic circuits. Each logic circuit constitutes a 2-out-of-4 logic circuit. One logic circuit outputs a protector energization signal to open a breaker that powers the control rod controller coils to scram the reactor. The protective device energizing signal output from the other logic circuit prompts the operation of the emergency boric acid injector and the spray in the storage container.

Incidentally, "Nuclear Handbook" (published by Ohmsha), 1976, p263 to 267, and particularly Table 9.6 of p264 shows 2 out-of-4 logic circuits.

[0004]

Japanese Patent Laid-Open No. 61-118801 discloses a reactor safety protection device for a pressurized water reactor. This reactor safety protector is one 2 out of 4
The logic circuit operates one coil of the control rod controller. However, a solenoid valve for a scrum that operates a control rod drive control unit, which is a target of a reactor safety protection device for a conventional boiling water reactor, has two exciting coils. Therefore, based on the description of Japanese Patent Laid-Open No. 61-118801, it is necessary to provide one 2-out-of-4 logic circuit for each exciting coil. Moreover, these 2 out of 4 logic circuits are described in the above-mentioned Nuclear Power Handbook, p.
Application of the 2 out of 4 logic circuit shown in Table 9.6 of H.264 is conceivable.

In this way, when two independent operating means are provided as operating means for one controlled device (for example, when two independent exciting coils are provided as in a boiling water reactor). ), If two out-of-four logic circuits are provided for each operating means in order to operate each operating means, the number of switches increases, the structure of the protection device becomes complicated, and the reliability deteriorates.

An object of the present invention is to provide a reactor safety protection device which can reliably perform a protection operation performed when two operating means are activated.

[0007]

According to the present invention, a trip signal is output when two or more of the state quantity signals of four sensors that detect the same state quantity of a nuclear reactor exceed a predetermined value. In each of the four signal processing systems, two out-of-four logical operations are performed and two out-of-four circuits are operated by a plurality of switches and two operating means that are operated by trip signals of the corresponding signal processing systems of the four signal processing systems. A logical operation is performed so that one control target device is operated when the two operation means are activated.

[0008]

In the quadrupled signal processing system, two out-of-four logics of the state quantity signal of the quadrupled sensor are performed to generate a trip signal, and two operation means are switched to two out-of-fours. Since it is used for the logical operation, the number of switches of the switchgear can be reduced and the reliability can be improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the basic concept of the present invention will be described with reference to FIGS. 1 and 2 in order to facilitate understanding of the present invention.

The reactor safety protection device shown in FIG. 1 has four systems consisting of one signal processing device, one switching circuit and one diagnostic device (for example, signal processing device 2, switching circuit 19A and abnormality diagnostic device 22A). Signal processing system 25A-25
Have D. In each signal processing system, the signal processing devices 1 to 4 are sensors A _{1 to} A ₄ , ..., N _{1 to} N ₄ , the signal processing device 2 is sensors A _{2 to} N ₂ , and the signal processing device 3 is sensor A. _{3 to} N ₃ , and the signal processing device 4 is connected to the sensors A _{4 to} N ₄ . 4 shown here in the same alphabet
The two sensors (eg A ₁ , A ₂ , A ₃ , A ₄ ) are arranged close to each other and have the same state quantity (hereinafter,
The same kind of state quantity) is measured. The sensors with different alphabets measure different state quantities or state quantities at different places (hereinafter referred to as different kinds of state quantities) even if the state quantities are the same. In the present embodiment, four sensors are provided for one state quantity as described above, but one sensor is provided and the output signal of this sensor is
You may input into the signal processing apparatuses 1-4 of each signal processing system, respectively. The signal processing devices 1, 2, 3 and 4 include redundant sensors A _{1 to} N ₁ , A _{2 to} N ₂ , A _{3 to} N ₃ and A _{4 to} N _4.
Each of the signals output from the device is captured and arithmetic processing is performed. When the processing result exceeds a specified value, trip signals a to d for scramming the plant are output.

The changeover circuit 19A has a changeover switch 20 and a power source 21 as shown in FIG. 2 as an example. The changeover switch 20 has fixed contacts 20A and 20B, a fixed terminal 20C, and a movable contact 20D that is always connected to the fixed terminal 20C. The power supply 21 is connected to the fixed contact 20B. The switching circuits 19B to 19D are also the switching circuit 19A.
It has the same structure as. The fixed contacts 20A of the switching circuits 19A to 19D are connected to the output ends of the signal processing devices 1 to 4, respectively. When each of the signal processing devices 1 to 4 is functioning normally, the movable contact 20D of each of the switching circuits 19A to 19D is connected to the fixed contact 20A.

The power circuit (switchgear) 5 has two switchgear parts (first switchgear) 5A and switchgear parts (second switchgear) 5B arranged in parallel. Each of the switch parts 5A and 5B is composed of four relays (or contactors). The switch part 5A is a relay 8
And relay 9 connected in series and arranged in parallel
0 and 11 are connected to the relay 9 in series. Relay 8
Is connected to the power supply 6. The switch part 5B is a relay 12
And the relay 13 are connected in series, and the relays 14 and 15 arranged in parallel are connected to the relay 13 in series. The power supply 7 is connected to the relay 12. The relays 8 to 15 have movable contacts 8A to 15A and fixed contacts 8B to 15B, respectively.

The relays 8 and 14 are connected to the fixed terminal 20C of the signal switching circuit 19A for inputting the trip signal a which is a signal for operating the relays. Similarly,
The relays 9 and 15 are connected to the fixed terminal 20C of the signal switching circuit 19B for inputting the trip signal b which is an operation signal, and the relays 10 and 12 are the signal switching circuit for inputting the trip signal C of the operation signal. The signal switching circuit 1 is connected to the fixed terminal 20C of 19C, and the relays 11 and 13 receive the trip signal d which is an operation signal.
It is connected to the fixed terminal 20C of 9D. During normal operation of the nuclear power plant, the movable contacts 8A to 15A are closed, and the movable contacts 8A to 15A are fixed contacts 8B to 1.
5B is in contact with each.

Output terminals of the relays 10 and 11 (switch section 5
The output end of A is the exciting coil 1 of the electromagnet 18 for scrum.
6 is connected. The output ends of the relays 14 and 15 (the output end of the switch portion 5B) are connected to the exciting coil 7 of the scrum electromagnet 18. The scrum electromagnet 18 is provided in the scrum solenoid valve 19.

Reference numerals 22A to 22D are abnormality diagnosis devices for diagnosing whether or not there is an abnormality in each of the signal processing devices 1 to 4.

In the nuclear reactor safety protection device of FIG. 1, the relays 8 to 15 and the exciting coils 16 and 17 in the power circuit 5 constitute a 2 out of 4 logic circuit. In other words, it can be said that the switch section 5A, the exciting coil 16 connected to the switch section 5A, the switch section 5A and the exciting coil 17 constitute a two-out-of-four logic circuit. Here, when the signal processing devices 1 to 4 output the trip signals a to d while the signal processing devices 1 to 4 are functioning normally (plant abnormal state), the movable contact 8A and 14A responds to the trip signal a, and the movable contacts 9A and 15A respond to the trip signal b.
A and 12A are opened by a trip signal C, and movable contacts 11A and 15A are opened by a trip signal d, so that the excitation coils 16 and 17 are in a non-excitation state. When both of the exciting coils 16 and 17 are in the non-excited state, the scrum electromagnet 18 operates and the scrum solenoid valve 19 opens. This causes a control rod drive (not shown) to quickly insert the control rods into the core and scram the reactor.

In FIG. 1, the logical configuration is 2 out of 4 in which the "0" level is prioritized.

Although the number of the electromagnetic valve for scrum 19 is shown as one, a plurality of electromagnetic valves for scrum 19 are provided,
Correspondingly, the power circuit 5 may be connected to each of the scrum solenoid valves 19, and the output signals of the switching circuits 19A to 19D may be applied to these power circuits in parallel to perform the scrum operation. .

The exciting coil 16 is controlled to be excited or de-excited by the switch section 5A, and the exciting coil 17 is controlled to be excited or de-excited by the switch section 5B. Assuming that the operation signal for making the exciting coil 16 in the non-excited state is A and the operation signal for making the exciting coil 17 in the non-excited state is B, these operating signals A and B are as follows.

[0020]

[Equation 1] A = ab (c + d)

[0021]

## EQU2 ## B = cd (a + b) Here, when the scrum signal applied to the scram electromagnetic valve 19 is Z, the scrum signal Z is expressed by the following equation.

[0022]

## EQU3 ## Z = A + B When the equations (1) to (2) are substituted into the equation (3), the following equation is obtained.

[0023]

## EQU00004 ## Z = abc + bcd + cda + dab (Equation 4) is defined by the following trip signals a, b, c and d:
If any two trip signals are logic “0”, Z = “0” even if the other trip signals are logic “1”
Becomes In other words, 2 out of 4 which gives priority to logic "0"
It can be seen that the reactor safety protection device can be realized by the logical configuration of.

Next, in the nuclear reactor safety protection device configured as described above, even if one signal processor breaks down or one signal processor is disconnected for maintenance, the remaining three signal processors will be replaced by two. It will be described that out-of-three logic can be configured.

This can be achieved by constructing one signal processing system with a signal processing device, a switching circuit and an abnormality diagnosing device as shown in FIG. That is, for example, the abnormality diagnosing device 2 which inputs the status signal of the signal processing device 1
When 2A determines the abnormality of the signal processing device 1 based on the input signal, the abnormality diagnosis device 22A disconnects the movable contact 20D of the changeover switch 20 of the changeover circuit 19A from the fixed contact 20A to form the fixed contact 20B. Connecting. Power supply 2
Reference numeral 1 is a DC power supply, which outputs a signal of logic "1". In this way, by outputting the signal of logic "1" by the switching operation of the switching circuit connected to the signal processing device in the abnormal state, the two out-of-three logic can be configured by the other three normal signal processing devices. In the changeover switch 20 of the changeover circuit 19A, the movable contact 20D in which the signal processing device to which the changeover circuit is connected is normal is in contact with the fixed contact 20A. The switching circuit transfers the movable contact 20D to the fixed contact 20B when disconnecting the abnormal signal processing device that transmits the trip signal output from the corresponding signal processing device to the power circuit 5.
, And a signal of logic "1" is forcibly transmitted to the power circuit 5. The changeover switch 20 is controlled by an operator's operation (not shown),
Alternatively, it may be performed by an instruction from the abnormality diagnosis device as described above. The abnormality diagnosis devices 22A to 22D can be realized by various means (for example, Japanese Patent Laid-Open No. 59-51393).

As an example, the case where the signal processing device 1 is disconnected will be described. When the signal processing device 1 is in an abnormal state, the diagnostic device 22A issues a command signal to connect the movable contact 20D of the changeover switch 20 of the changeover circuit 19A to the fixed contact 20.
Switch from A to fixed contact 20B. At the moment when the connection of the movable contact 20D is switched from the fixed contact 20A to the fixed contact 20B, the changeover switch 20 causes chattering, and the output signal from the fixed terminal 20C becomes logical "0" or "1". fluctuate. However, since the power circuit 5 and the exciting coils 16 and 17 have a 2-out-of-4 logical configuration, there is no chance of accidentally scramming the reactor by chattering. Moving contact 20C is fixed contact 2
The voltage value of the power supply 21 connected to 0B is output. This voltage value is a value that becomes "1" as a logic signal. That is, the signal a output from the switching circuit 19A is the logic "1".
Becomes Substituting the value of the signal a into the equation (4), the scrum signal becomes the following equation.

[0027]

[Equation 5] Z = bc + cd + db (Equation 5) As is apparent from the equation, when the signal processing device 1 is disconnected, the output signal of the switching circuit 19A of the signal processing system 25A is forced to be logical "1". As a result, the 2 out-of-3 logic can be formed by the output signals from the remaining signal processing devices 2 to 4. As a result, when one signal processing device is disconnected by the switching circuit, even if one of the remaining three normal signal processing devices fails, the reactor is erroneously scrammed when the reactor plant is normal, It is possible to avoid the situation where scrum cannot be performed when scrum is required in the event of an abnormal reactor plant. Further, in the above case, the failure of the remaining three signal processing devices has been described, but the same applies to the case where the switching circuit connected to these signal processing devices fails. The same applies when a relay connected to these switching circuits fails. In other words, even if one signal processing device is disconnected, it is possible to satisfy the prevention of erroneous scrum and the single failure criterion (the scrum function is maintained regardless of any failure of one of the other devices). .

In the above example, the case where the signal processing device 1 is disconnected has been described, but the same applies when the other signal processing devices 2, 3 and 4 are disconnected. When disconnecting the signal processing device 2, if the switching circuit 19B is controlled so that b = 1, the scrum signal Z becomes as follows from the equation (4).

[0029]

Z = ac + cd + da Next, when disconnecting the signal processing device 3, if the switching circuit 19C is controlled so that c = 1, the scrum signal Z becomes as follows from the formula (4). .

[0030]

## EQU7 ## Z = ab + bd + da Further, when the signal processing device 4 is disconnected, if the switching circuit 19D is controlled so that d = 1, the scrum signal Z becomes as follows from the equation (4).

[0031]

[Equation 8] Z = ab + bc + ca That is, in any case, when one signal processing device is disconnected, the output signal of the signal processing system is forcibly set to the logic "1" by the switching circuit to output 2 out. The logical configuration of 3 of 3 can be realized, and the reliability of the reactor safety protection device can be further enhanced.

As described above, the reactor safety protection device shown in FIG. 1 can obtain the following effects. That is,
Independently provided exciting coil 16 (first operating means) and exciting coil 17 (second operating means) for operating the electromagnetic valve for scrum, which is a controlled device, and power as an opening / closing device for operating these exciting coils Since the logic circuit of 2 out of 4 can be configured together with the circuit 5, the structure of the switchgear is significantly simplified, and the simplification improves the reliability of the reactor safety protection device. Further, in a nuclear power plant, a system of 2 out of 4 logic can be configured by leaving the configuration of the solenoid valve having two exciting coils or the solenoid valve having one exciting coil as it is, and among the signal processing devices of four systems. A 2 out-of-3 logic configuration can be built so that one signal processing device will not fail or will not operate accidentally even if one signal processing device is disconnected for maintenance. It is possible to further improve reliability and realize a reactor safety protection device.

In the present invention, the signal processing system 25 in the reactor safety protection device shown in FIG. 1 is constructed as shown in FIG.

5 is different from FIG. 1 in that the outputs of the sensors A _{1 to} A ₄ , ..., N _{1 to} N ₄ are connected to the signal processor 1A,
Input is made to all of 2A, 3A and 4A. The configuration of the power circuit 5 for inputting the outputs of the switching circuits 19A, 19B, 19C and 19D is the same as that of FIG.
A scrum signal is applied to the exciting coils 16 and 17 provided in the electromagnet 18 of the scrum solenoid valve 19.

The signal processing device 1A comprises sensors A _{1 to} A ₄ ,
..., N ₁ to N digital trip modules each connected to _{4 DTM-A1~DTM-A2, ...} , DT
It has M-N1 to DTM-N4. The digital trip modules DTM-A1 to DTM-A4 are used for the sensors A _{1 to} A ₄ which measure the same kind of state quantity, and the digital trip modules DTM-N1 to DTM-N.
4 are connected to sensors N _{1 to} N ₄ for measuring the same kind of state quantity, respectively. 4 digital inputs of the same state quantity
For each trip module (eg DTM-A1 to DTM
-Create one group in A2). There are as many groups (n) as there are different types of state quantities. Two out-of-four logic circuits are provided for each group, and the output terminals of four digital trip modules belonging to one group are connected to one two-out-of-four logic circuit. That is, the digital trip modules DTM-A1 to DTM-A4 are 2 out of 4
The digital trip modules DTM-N1 to DTM-N4 are respectively connected to the logic circuit 29A and the 2-out-of-4 logic circuit 29N. 2 in signal processor
The number of out-of-four logic circuits is n. , N of two out-of-four logic circuits 29A, ..., 29N are connected to one out-of-n logic circuit 30. Other signal processing device 2
A, 3A, and 4A also have the same configuration as the signal processing device 1A. The 1-out-of-n logic circuit 30 of each of the signal processing devices 1A, 2A, 3A, and 4A corresponds to the corresponding switching circuit 1
9A, 19B, 19C and 19D, respectively. Each switching circuit 19A, 19B, 19 in this embodiment
C and 19D are connected to each relay of the power circuit as in FIG.

Each digital trip of the signal processing device
The module inputs the state quantity signal output by the corresponding sensor and outputs a trip signal when the state quantity signal exceeds a specified value. Each two out-of-four logic circuit of the signal processing device outputs a trip signal when at least two digital trip modules of the four digital trip modules of each group output a trip signal. 1 out-of-n logic circuit is
The trip signal a (or trip signal b, c, or d) is output when a trip signal is output from at least one 2 out of 4 logic circuit 26A to 26N. These trip signals a, b, c and d open the relays of the power circuit as in FIG. 1 to put the exciting coils 16 and 17 into a non-excited state. As a result, the electromagnet 18 operates, the electromagnetic valve 19 for scrum opens, and the nuclear reactor scrams.

In such an embodiment of the present invention, the same effect as that of the reactor safety protection device shown in FIG. 1 can be obtained, and in addition, 2 out of 4 signal processing devices 1A to 4A can be obtained.
Since the logic circuit is used, high reliability of the signal processing device can be achieved. As a result, the reliability of the reactor safety protection device is further improved.

3 and 4 show modified examples of the power circuit 5, respectively.

In FIG. 3, the relays 9 and 15 are connected to the fixed terminal 20C of the switching circuit 19C to input the trip signal c, and the relays 10 and 12 to input the trip signal b to the switching circuit 19B. Fixed terminal 2
0C. Therefore, the relay 8 of the switch unit 5A operates with the trip signal a, the relay 9 operates with the trip signal c, the relay 10 operates with the trip signal b, and the relay 11 operates with the trip signal d. On the other hand, the relay 12 of the switch unit 5B is the trip signal b and the relay 13 is the trip signal d.
Then, the relay 14 is operated by the trip signal a and the relay 15 is operated by the trip signal c. The exciting coil 16 is
Excitation and non-excitation are controlled by the switch section 5A, and excitation coil 17 is controlled by the switch section 5B. As a result, the scrum signal Z applied to the solenoid valve 19 for scrum is given by the following equation.

[0040]

## EQU9 ## Z = ac (b + d) + bd (a + c)

[0041]

Z = abc + bcd + cda + dab (Equation 10) As is apparent from the equation (10), the scrum signal Z by the power circuit 5 and the exciting coils 16 and 17 shown in FIG. 3 has the same two out-of-four logical configuration as the equation (4). Has become.

Next, in the power circuit 5 shown in FIG. 4, the relays 8 and 14 are connected to the fixed terminal 20C of the switching circuit 19B in order to input the trip signal b, and the relay 10
And switching circuit 1 for inputting the trip signal a.
It is connected to the fixed terminal 20C of 9A. Therefore, the relay 8 of the switch unit 5A is operated by the trip signal b, the relay 9 is operated by the trip signal c, the relay 10 is operated by the trip signal a, and the relay 11 is operated by the trip signal d. on the other hand,
The relay 12 of the switch unit 5B has a trip signal a, the relay 13 has a trip signal d, and the relay 14 has a trip signal b.
Then, the relays 15 are respectively operated by the trip signal c. Therefore, the excitation and non-excitation of the excitation coil 16 are controlled by the switch unit 5A. Further, the excitation and non-excitation of the excitation coil 17 is controlled by the switch section 5B. As a result, the scrum signal Z applied to the solenoid valve 19 for scrum is given by the following equation.

[0043]

[Equation 11] Z = bc (a + d) + ad (b + c)

[0044]

## EQU12 ## Z = abc + bcd + cda + dab As is clear from the equation (12), the scrum signal Z has the same two out-of-four logical configuration as the equation (4).

FIG. 6 shows another example of the power circuit.

The power circuit 5C shown in FIG. 6 includes a switch section 5D in which relays 31 and 32 are added to the switch section 5A constituting the power circuit 5 shown in FIG. 1, and relays 33 and 34 are added in the switch section 5B. And the switch part 5E. That is, the relays 31 and 32 arranged in parallel
The input ends of are connected to the output ends of the relays 10 and 11 arranged in parallel and connected to each other. Output ends of the relays 13 and 32 are connected to the exciting coil 16. The input ends of the relays 33 and 34 are connected to each other. The output terminals of the relays 14 and 15 are also connected to each other. The output terminals of the relays 14 and 15 thus connected to each other are connected to the input terminals of the relays 33 and 34 connected to each other. The output ends of the relays 33 and 34 are connected to the exciting coil 17.

Although not shown in detail, the relays 8 and 3
1 and 33 are connected to the switching circuit 19A of the signal processing system 25A for inputting the trip signal a which is an operation signal. Relays 9, 32 and 34 are trip signals b
Switching circuit 19B of signal processing system 25B for inputting
Connected to. Further, the relays 10, 12 and 14 are input to the switching circuit 19C of the signal processing system 25C for inputting the trip signal c, and the relays 11, 13 and 15 are input to the switching circuit 19D of the signal processing system 25D for inputting the trip signal d. Respectively connected to.

When the scrum signal applied to the scrum solenoid valve 19 is Z, the scrum signal Z is expressed by the following equation.

[0049]

Z = ab (c + d) (a + b) + cd (c + d) (a + b) = ab (c + d) + cd (a + b) = abc + bcd + cda + dab (Equation 13) As is clear from the formula, this configuration has been described so far. Similar to the configuration, it has a two-out-of-four logical configuration that prioritizes logical "0". Moreover, the switch parts 5D and 5
By making E redundant, it is possible to further improve the reliability of the power circuit 5C. For example, even if the relays 8 and 9 are broken and remain "closed", the excitation of the exciting coil 16 is released even if the relays 30 and 31 are normal. In other words, it can be seen that the scrum function is maintained.

Another embodiment of the signal processing device will be described with reference to FIG. The signal processing device 35 of this embodiment is composed of a microprocessor. As shown in FIG. 7, the signal processor 35 includes a data acquisition circuit 35A, a bus 35B,
It comprises a CPU 35C, a RAM 35D, a ROM 35E and a data output circuit 35F. The data acquisition circuit 35 connected to the n types of sensors is connected to the bus 35B. The bus 35B includes a CPU 35C, a RAM 35D, and a RO
They are connected to the M35E and the data output circuit 35F, respectively. The ROM 35E stores the processing procedure shown in FIG.

The CPU 35C performs arithmetic processing based on the processing procedure stored in the ROM 35E. RAM35E
Is the data and CP input from the data acquisition circuit 35A.
Store the data obtained at U35C. This signal processing device 35 is used in place of each of the signal processing devices 1 to 4 in FIG.

The processing in FIG. 7 is performed as shown in the flowchart of FIG.

The data signals measured by the sensors A _{1 to} A ₄ , ..., N _{1 to} N ₄ are transferred to the RA through the data acquisition circuit 35A.
Captured by M35D. CPU35C is ROM35E
To read the processing procedure shown in FIG. First, step 48
, The measurement data of the sensors A _{1 to} A ₄ , ..., N _{1 to} N ₄ , that is, the measured state quantity signals of all different types are
Each of them is input to one signal processing device 35. Step 4
Determine whether at least two measurement data out of four measurement data of the same type compared in 9 exceeds the specified value.
(2 out-of-4 logic judgment) If it exceeds, a trip signal (logic "0") is output (step 53). In step 53, for each of n different types of measurement data, it is determined whether or not at least two types of measurement data of the same type exceed specified values. Then, the process proceeds to step 54.
It is determined whether at least one of the two out-of-four logic determination results of the different types of measurement data in step 53 is logical "0" (step 54). If it is determined in step 54 that there is no logical "0" determination result, the process of step 51 is performed and the logical "0" is determined.
If there is even one determination result of step 52, the process of step 52 is performed.

As described above, in FIG. 7, each signal processing is constituted by the microprocessor, so that the apparatus can be made compact.

[0055]

As described above, according to the present invention, two out-of-four logical operations are performed in order to generate a trip signal based on the state quantity signal of the quadrupled sensor, and two operating means are switched. Since it is used for 2 out of 4 logical operations, the number of switches of the switchgear can be reduced, and the reliability of the reactor safety protection device can be significantly improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining a basic idea of the present invention.

FIG. 2 is a detailed configuration diagram showing an example of a switching circuit in FIG.

FIG. 3 is a configuration diagram showing a modified example of a power circuit.

FIG. 4 is a configuration diagram showing another modification of the power circuit.

FIG. 5 is a configuration diagram of a signal processing device according to an embodiment of the present invention.

FIG. 6 is a configuration diagram showing another example of a power circuit.

FIG. 7 is a configuration diagram of another signal processing device according to an embodiment of the present invention.

FIG. 8 is a flowchart for explaining the operation of the signal processing device in FIG.

[Explanation of symbols]

1 to 4, 1A to 4A, 35 ... Signal processing device, 5, 5C,
5F, 26 ... Power circuit, 5A, 5B, 5D, 5E, 2
6A, 26B ... Switch unit, 8-15, 31-34, 40
... 47 ... Relay (or contactor), 16, 17 ... Exciting coil, 18 ... Electromagnet, 19 ... Electromagnetic valve for scrum, 1
9A to 19D ... Changeover circuit, 20 ... Changeover switch, 25A
25D ... Signal processing system.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Atomi Noguchi 5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi Co., Ltd. Omika Plant (72) Inventor Shigeru Izumi 1168 Moriyama-cho, Hitachi-shi, Ibaraki Co., Ltd. Hitachi, Ltd. Energy Research Laboratory (72) Inventor, Satoshi Suzuki 1168 Moriyama-cho, Hitachi, Ibaraki Prefecture Hitachi Energy Research Institute (72) Inventor Fumiyasu Okido 1168, Moriyama-cho, Hitachi City, Ibaraki Hitachi Energy Laboratory ( 56) References JP-A 61-118801 (JP, A) JP-A 62-113204 (JP, A)

Claims (4)

(57) [Claims] 1. Four sensors for detecting the same state quantity of a nuclear reactor and two state quantity signals of the four sensors by inputting state quantity signals detected by the four sensors. A trip signal is output when the above exceeds a predetermined value.
First to fourth signal processing systems each having two out-of-four logic means, two operation means, one controlled device operated when the two operation means are activated, It has a plurality of switches which are operated by the trip signals of the second, third and fourth signal processing systems and which are operated by the trip signals of the corresponding signal processing system. The plurality of switches and the two operating means are provided. 2nd 2 out of 4
A reactor safety protection device comprising a switchgear constituting a logic means. 2. The switch device according to claim 1, wherein the switch device is opened by a trip signal of the first signal processing system and the first and fifth switches and the trip signal of the second signal processing system. Second and sixth switches, third and seventh switches operated by a trip signal of the third signal processing system, and fourth and eighth switches operated by a trip signal of the fourth signal processing system. The first switch and the second switch are connected in series to a parallel circuit in which the third and fourth switches are connected in parallel to form a first switching circuit, and the fifth and sixth switches are connected in parallel. The seventh switch and the eighth switch are connected in series to a parallel circuit to form a second switching circuit, and the first operating means is connected to the output end of the first switching circuit, and the second switching circuit is connected. Output end of Reactor security apparatus characterized by comprising connecting said second operation means. 3. The device according to claim 1, wherein each of the first and second operating means is an exciting coil, and the device to be controlled is an electromagnetic valve having an electromagnet having the two exciting coils. Reactor safety protection device. 4. The reactor safety protection device according to claim 1, wherein each of the four signal processing systems can output a logic signal for holding the closed state of the switch to be opened by a trip signal.