JPS58120194A - Protection device for atomic power plant - 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 protection device for a nuclear power plant, and in particular to a protection device for a nuclear power plant that effectively utilizes the functions of a process computer to improve the protection function of important equipment in an atomic couplant. Regarding protective devices.

Technical background of the invention In nuclear power plants, when an abnormality occurs in the reactor, turbine, generator, or other important equipment, it is immediately detected and the equipment is automatically stopped or interfaced before it develops into a serious accident. A number of locking protection devices are provided.

These protective devices are essential for maintaining plant safety, but if the protective devices themselves are not sufficiently reliable, they will unnecessarily reduce the plant's operating rate. Conventionally, various measures have been taken to improve the reliability of protection devices.

In other words, for example, if a single signal is used to activate a protection device, the protection device will be activated even if there is an error in the signal itself. is detected by three or four side covers, and the protection device is activated by the matching signals.

Problems with the Background Art The method described above in which the same signal is detected by a plurality of measuring instruments has the disadvantage that the number of installed measuring instruments increases, which makes maintenance of the equipment difficult and increases the cost of the plant.

Purpose of the Invention The present invention has been made to eliminate the above-mentioned disadvantages in conventional protection devices, and by effectively utilizing the output signal of the process computer installed as standard in the atomic coupler, The object of the present invention is to provide a protection device for a nuclear power plant that improves the reliability of the protection function without increasing the number of devices installed.

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention uses only one measuring device for the same signal to detect the status of important equipment of an atomic couplant, and uses the output signal of this measuring device and the output signal of this measuring device. This is a protection device for a nuclear power plant configured to perform a protection operation based on a signal that matches the output signal of a process computer that has a correlation with the output signal of a process computer.

Embodiments of the Invention Hereinafter, embodiments of the invention shown in the drawings will be explained in detail.

The figure illustrates a protection device that automatically shuts down a turbine when the water level inside a nuclear reactor rises abnormally in a nuclear reactor.

The steam generated in the reactor 1 is led to the turbine 2 through the main steam pipe 2, and after doing work there, it becomes condensed water, which is pressurized by the water supply pump 4, and then transferred to the water supply pipe. 5 into the reactor 1 again.

The flow rate signals from the main steam flow rate detector 6 attached to the main steam pipe 2 and the feed water flow rate detector 7 attached to the water supply pipe 5 are transmitted to other important equipment attached to the reactor 1, turbine 3, generator, etc. It is input to the process computer 8 along with signals from various instruments and measuring instruments (not shown).

3- This process computer constantly scans input signals from a large number of various measuring instruments online, and monitors various performance calculations and changes in plant status.

The water level inside the reactor 1 is measured by a 1-channel reactor water level detector 9.
and its output is input to the turbine protection device 10.

On the other hand, the process computer 8 constantly compares and checks the difference between the main steam flow rate and the feed water flow rate based on the signals from the main steam flow rate detector 6 and the feed water flow rate detector 7, and the difference between the two is determined to be a predetermined value. When the value exceeds 100, a signal is output to the turbine protection device 10.

The turbine protection device 10 outputs a turbine stop signal to the turbine 6 to stop the turbine 6 on the condition that the signal from the process computer 8 and the signal from the water level detector 9 match.

In the above, the water level rise in the reactor is correlated with the difference between the feed water flow rate and the main steam flow rate, and if both flow rates are balanced, no water level change will occur. If the water level detector outputs a signal indicating an abnormal rise in the water level even though the signal indicating the abnormal flow rate difference -4= is not output, there is an error in the water level detector or its transmission system. It is assumed that the signal is being picked up.

In such a case, in the protection device of the present invention, the turbine protection device sends a turbine stop signal only when the output from the process computer and the output from the water level detector satisfy the AND condition. The protection is more reliable and the turbine is not tripped more than necessary.
It is possible to prevent the operating rate of the plant from decreasing.

In the above example, the feed water flow rate and main steam flow rate, which are the input signals of the process computer, are conventionally input for calculating the reactor core performance, so new input signals are required when applying the present invention. There is no need to add any additional measuring equipment, just add logic to compare and judge the feed water flow rate and main steam flow rate in the process computer1. In the above explanation, the reactor water level has risen abnormally. Although the present invention has been described using an example in which the turbine is automatically stopped when the reactor water level falls below a specified value, the present invention can be applied in the same manner as above to the case where the reactor is automatically stopped when the reactor water level falls below a specified value. is a signal that has been conventionally input to a process computer, and if it is a signal that has a correlation with the output signal of a separate measuring instrument, a protection circuit can be built in the same manner as described above.

Effects of the Invention As described above, the present invention makes it possible to improve the reliability of the protection device without increasing the number of channels in the autopsy side cover by utilizing the process computer that is installed as standard in nuclear power plants. Compared to the conventional multiplexing method in which multiple devices are installed together to perform a single function, it is highly economical and eliminates problems such as space constraints, increased number of maintenance parts, and increased costs. A protection device that can contribute to improving the operating rate of a plant can be obtained.

[Brief explanation of drawings]

The figure is a system diagram showing an example in which the present invention is applied to a turbine protection device that automatically stops a turbine when the water level of a nuclear reactor rises. 1 ..... Reactor 2 ..... Main steam pipe 6 ..... Turbine 4 ..... Water pump 5 ..... Water supply pipe 6 .... ...Main steam flow rate detector 7 ...Feed water flow rate detector 8 ...Process computer 9 ...Water level detector 10 ...Turbine protection device (7317) Representative Patent Attorney Noriyuki Chika (and 1 other person)

Claims (1)

[Claims] 1. A process computer that uses only one measuring device for each signal to detect the status of important equipment in an atomic couplant, and has a correlation between the output signal of this measuring device and this output signal. A protection device for a nuclear power plant, characterized in that the protection device is configured to perform a protection operation based on a signal that matches an output signal of the device. 2. The measuring device is a water level detector that generates an output due to an abnormal rise in the reactor water level, and the output signal of the process computer is a signal indicating the difference between the main steam flow rate and the feed water flow rate, and the output signal of the water level detector and the The protection device for a nuclear power plant according to claim 1, wherein the protection device for a nuclear power plant is configured to send a stop signal to the turbine when the output signals of the process computer match.