JPS62100698A - Neutron measuring system in nuclear reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a neutron measurement system in a nuclear reactor such as a boiling water nuclear power plant.

[Technical Background of the Invention and Problems Therewith] Generally, boiling water nuclear power plants and the like are provided with an in-reactor neutron measurement system to measure the neutron flux of neutrons generated within the reactor.

The in-reactor neutron measurement system is a neutron source region measurement system (S RM) that measures neutron flux of 103 to 109 nv from subcritical to intermediate region in order to measure a wide range of neutron flux from reactor startup to output operation. ), an intermediate region measurement system (IR~1) that measures the neutron flux of 188~io”nv from near criticality to output operation, and 101~io”nv neutron flux during output operation.
It is composed of a power range measurement system (PRM) for measuring neutron flux of 2 to io''nv.

In the in-reactor neutron measurement system with the above configuration, SRM,
When the power of the reactor increases and the neutron flux exceeds its measurement range, the IRM's neutron detector is removed from inside the reactor to prevent sensitivity loss. Also, when the reactor is shut down, the neutron flux decreases, and when it reaches the respective measurement range,
It is inserted into the reactor and measurements are taken. For this reason, SRM
, IRM is connected to drive motor units 1 to 1 provided in the containment vessel and a control device provided in a central control room to serve as a subsidiary part of the drive motor units.

When shutting down a nuclear reactor, SRM, I
The purpose of inserting an RM into a nuclear reactor is to ensure that the reactor's output is reduced and that the reactor is shut down. This operation is particularly important when a nuclear reactor is brought to an emergency shutdown for some reason. In the event of an emergency shutdown, operators must immediately insert the SRM and IRM and monitor the neutron flux inside the reactor. Therefore, it is necessary to confirm that the reactor has definitely stopped.

When performing this operation, first insert the IRM. IR
The measurement range of M can be changed according to the neutron flux to be measured, and range switching is performed by a range changeover switch provided on the central control panel. I
After inserting the RM, the operator changes the range switch according to the decrease in neutron flux, and inserts the SRM when the neutron flux falls below a certain range.

This IRM and SRM insertion operation is part of the basic operations when a reactor is shut down in an emergency. There are also many neutron detectors to be installed. Therefore, manually inserting the SRM and IRM increases the burden on the operator, and there is a problem that the reliability of the reactor may be compromised due to erroneous operation.

[Purpose of the Invention] The present invention has been made in response to the conventional situation, and can automatically insert the SRM and IRM into the reactor during an emergency shutdown of the reactor, thereby reducing the operational time compared to the conventional method. The present invention aims to provide an in-reactor neutron S1 measurement system that can significantly reduce the burden on personnel, prevent the occurrence of erroneous operations, and improve the safety of a nuclear reactor.

[Summary of the invention] That is, the present invention provides a neutron detector that is handled during power operation of a nuclear reactor and detects low-level neutron flux at times other than power operation, and a method for inserting and extracting this neutron detector into the reactor. In an in-reactor neutron measurement system comprising a drive motor unit for a nuclear reactor and a control device for controlling the drive motor unit, the control device and a nuclear reactor output an emergency stop signal for the reactor when an abnormality occurs. By connecting the neutron detector to a safety protection system and automatically inserting the neutron detector into the reactor and activating it in response to the emergency stop signal, the burden on operators is significantly reduced and the occurrence of erroneous operation is prevented. It is designed to improve the safety of nuclear reactors.

[Embodiment of the Invention] The details of the present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 shows the configuration of an in-reactor neutron measurement system according to an embodiment of the present invention. The in-reactor neutron measurement system of this embodiment includes a neutron detector 1 for SRM and an IR
The M neutron detector 2 is connected to an SRM drive motor unit 3 and an IRM drive motor unit 4 via flexible shafts, and the SRM drive motor unit 3 and IRM drive motor unit 4 are connected to the SRM drive motor unit 3 and IRM drive motor unit 4, respectively. Control neck 5, IR~1 control device 6
It is connected to the. The SRM control device 5 and the IRM control device 6 include a manual operation unit 7 that enables manual operation.
, a range changeover switch 8 for IRM, and a reactor safety protection system 9 that generates an emergency stop signal for emergency shutdown of the reactor when an abnormality occurs in the plant are connected.

The SRM control device 5 and IRM control device 6 of the in-reactor neutron measurement system, which is composed of such an IRM, SRM, and PRM (not shown), constantly monitor the presence or absence of an emergency stop signal, and detect abnormalities within the plant. occurs,
When an emergency stop signal is output from the reactor safety protection system 9, operations are performed as shown in flowcharts 1 to 1 shown in FIGS. 2 and 3.

As shown in FIG. 2, in the IRM control device 6, when an emergency stop signal is input (a) and the automatic/manual changeover switch is set to automatic (b), all the power to the IRM drive motor unit 4 is turned on. C), select all the IRM neutron detectors d>, and output the IRM continuous insertion signal (
e).

On the other hand, in the SRM control unit @5, as shown in Fig. 3, an emergency stop signal is input (f) and the automatic/manual changeover switch is set to automatic (g). Turn on all the power supplies of 3 h), select all SRM neutron detectors 1 i), wait until the IRM range switch is manually set below a certain range (j), and when the range is below this range, Outputs the SRM continuous insertion signal (k).

When the SRM and IRM continuous insertion signals are output from the SRM control device 5 and the rRM control device 6 to the SRM drive motor unit 3 and the IRM drive motor unit 4, the SRM drive motor unit 3 and the IRM drive motor unit 4 Rotate the motor, SRM neutron detector 1,
The IRM neutron detector 2 is inserted into the reactor to the position regulated by the limit switch.

The operation described above is based on the manual operation of the manual operation unit 7F.
This can also be done manually by switching the automatic changeover switch to manual.

That is, in the in-reactor neutron measurement system of this embodiment with the above configuration, when an abnormality occurs in the plant and an emergency stop signal is generated from the reactor safety protection system 9 to stop the reactor, the SRM neutron Since the detector 1 and IRM neutron detector 2 are automatically inserted into the reactor and activated, the burden on operators can be significantly reduced compared to conventional methods, and the possibility of erroneous operation is also greatly reduced. can be reduced.

[Effect of the invention] As described above, in the in-reactor neutron h1 measurement system of the present invention, the SRM and IRM
can be automatically inserted into the reactor, greatly reducing the burden on operators compared to conventional methods, and preventing the occurrence of erroneous operations, thereby improving the safety of the reactor. I can do it.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an in-reactor neutron measurement system according to an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the IRM control device of the in-reactor neutron measurement system shown in FIG. FIG. 3 is a flowchart showing the operation of the SRM control device of the in-reactor neutron measurement system shown in FIG. 1...-3RM neutron detector 2...
...IRM neutron detector 3 ......SR
M drive motor unit 4...IRM drive motor unit 5...SRM control device 6...IRM control device 9...・・・・・・Reactor safety protection agent Patent attorney Nori Chika Ken Shu Kanshu Hirofumi Mitsumata Figure 1 (Says $2,000) Figure 2 Figure 3

Claims (1)

[Claims] (1) A neutron detector that is pulled out during power operation of the nuclear reactor and detects low-level neutron flux at times other than power operation, and a drive motor unit for inserting and pulling out this neutron detector into the reactor; In an in-reactor neutron measurement system comprising a control device for controlling this drive motor unit, the control device is connected to a reactor safety protection system that outputs an emergency stop signal for the reactor when an abnormality occurs, A neutron measurement system in a nuclear reactor, characterized in that the neutron detector is automatically inserted into the reactor and activated by the emergency stop signal.