JPS6394195A - Controller for nuclear power plant - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a control device for a nuclear power plant that responds to load shedding in an electric power system.

(Prior art) For example, in a boiling water nuclear power plant, if the load on the power plant suddenly decreases due to an accident or other cause in the power system that loads the power plant, the speed of the turbine generator In order to suppress the rise, the main steam control valve is suddenly closed to rapidly reduce the amount of steam flowing into the turbine. At this time, in order to treat the surplus steam generated by the reactor and prevent the reactor pressure from increasing, a bypass device is provided to guide the surplus steam to the turbine condenser, as is well known.

Some bypass devices are designed to handle the maximum amount of steam generated by the reactor (full-capacity bypass), but generally they only have the capacity to handle a portion of the maximum amount of steam generated (partial-capacity bypass). In the case of a nuclear power plant with partial capacity bypass, in which the amount of steam at the time of load shedding exceeds the bypass capacity, the main steam relief valve must be closed in order to avoid reactor shutdown due to a rise in reactor pressure. Devices have been proposed that are simultaneously released to release steam into the pool water of the suppression chamber.

(Problem to be Solved by the Invention) The pressure suppression chamber is equipped with pool water in order to maintain its function in accordance with the main purpose of condensing the primary coolant discharged into the reactor containment vessel. It is necessary to keep the water level and temperature constant, and if these rise,
Based on the monitoring results, a residual heat removal system connected to the pressure suppression chamber is activated. However, if the water level and temperature continue to rise, it is assumed that normal functionality cannot be maintained and the reactor is shut down.

Here, if the surplus steam at the time of load shedding is guided to the pressure suppression chamber like the above-mentioned device, the water level and water temperature of the pool water will rise at the time of load shedding. however,
As the residual heat removal system is started based on the operator's monitoring results as described above, it does not rapidly follow the rise in pool water level and water temperature caused by the release of the main steam relief valve during load shedding. Unfortunately, there is a high possibility that the reactor will be shut down, and there is a problem that the effect of disposing of excess steam by opening the main steam relief valve is likely to be uncertain.

The purpose of the present invention is to reduce the chance of reactor shutdown due to rise in pool water level and water temperature when the main steam relief valve used in nuclear power plants with partial capacity bypass operates during load shedding. The objective is to provide a control device for a nuclear power plant that can perform

[Structure of the invention]

(Means for Solving the Problems) In the present invention, a nuclear power plant has a main steam relief valve opening means that is used in combination with a partial capacity bypass device that processes surplus turbine supply steam when the generator load suddenly decreases. means for activating the pool water cooling system in the suppression chamber of the residual heat removal system by means of a deviation signal energizing the opening of the main steam relief valve in response to a comparative difference between the generator output signal and the turbine output signal; has been established.

(Function) Even if the partial capacity bypass device is activated when the load on the generator suddenly decreases, and the main steam relief valve is opened and excess steam is injected into the pool water, the pool water cooling device is activated immediately, so the pool water is Temperature rises will be suppressed and unnecessary reactor shutdowns will not be induced.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

The reactor containment vessel 1 houses a reactor pressure vessel 2 containing a reactor core (not shown). A pressure suppression chamber 3 is provided at the bottom of the reactor containment vessel 1 and stores pool water 4.

A main steam pipe 5 is led out from the reactor pressure vessel 2 by penetrating the reactor containment vessel 1 and, after a main steam control valve 6 is inserted, reaches a turbine 8 which is connected to a generator 7 . Further, a bypass pipe 1o branched from the main steam pipe 5 and having a turbine bypass valve 9 inserted therein is connected to the condenser 11. Note that main steam isolation valves 12 and 12 are provided inside and outside the penetration portion of the main steam pipe 5 through the reactor containment vessel 1.

Further, a relief pipe 14 having a main steam relief valve 13 inserted therein is branched from near the outlet of the main steam pipe 5 from the reactor pressure vessel 2 and introduced into the boule water 4 .

The piping 15 is led out from the pressure suppression chamber 3#, and after the pump 16 and the heat exchanger 17 are inserted, they are introduced into the pressure suppression chamber 3 again, and thereby the pool water cooling device of the pressure suppression chamber of the residual heat removal system is It consists of 18.

A cooling pipe 19 through which seawater flows is connected to the heat exchanger 17 .

A generator output signal (actual load signal) 21 taken out by an appropriate detection means from the output side connected to the power system 20 of the generator 7, and a generator output signal (actual load signal) taken out by an appropriate detection means provided in the turbine 8. A comparator 23 is provided which receives a turbine output signal (or a load request signal) 22 as an input, and the output of this comparator 23 is connected to the main steam relief valve 13, and a main steam relief valve opening means is provided. There is. Furthermore, the output of the comparator 23 is determined by the control device 2 which is a starting means for the pool water cooling device 18 of the residual heat removal system that operates the pump 16.
4 is also entered.

Next, the effect will be explained.

The steam generated in the reactor pressure vessel 2 is supplied to the turbine 8, which is rotated by the main steam control valve 6, which is opened with the main steam isolation valve 12 open and the turbine bypass valve 9 closed. 7 is supplied to the power system 20. At this time, the generator output signal 21 and the turbine output signal 22 are in balance, and no output is generated from the comparator 23, so the main steam relief valve 13 and the control device 24 are not energized.

For example, if the load on the generator 7 suddenly decreases due to an accident occurring in the electric power system 20, the main steam control valve 6 is throttled, the turbine bypass valve 9 is opened, and the generator output signal 21 is Since the equilibrium with the turbine output signal 22 is lost, an output of the comparator 23 is generated, the main steam relief valve 13 is opened, and the excess steam is also released into the pool water 4. As a result, the temperature of the pool water tends to rise, but the output of the comparator 23 is also input to the control device 24 at the same time, and the pool water cooling device 18 of the residual heat removal system is started immediately, so cooling of the pool water 4 starts. be done.

Therefore, when the load on the generator 7 suddenly decreases, the temperature of the pool water 4 will rise due to surplus steam injected into the pool water 4 via the main steam relief valve 13, and the nuclear reactor will not be shut down due to this.

〔Effect of the invention〕

As described above, according to the present invention, even during load shedding in a nuclear power plant that has a surplus steam processing device that uses a partial capacity bypass and a means for opening the main steam relief valve, it is possible to prevent reactor shutdown due to a rise in temperature of the pool in the pressure suppression chamber. It has the effect of preventing

[Brief explanation of the drawing]

The figure is a system diagram showing one embodiment of the present invention. 1... Reactor containment vessel, 2... Reactor pressure vessel, 3... Pressure suppression chamber, 4... Pool water, 5
...Main steam pipe, 6...Main steam control valve, 7
... Generator, 8... Turbine. 9... Turbine bypass valve, 10... Bypass piping, 13... Main steam relief valve 18... Pool water cooling device, 21... Generator output signal, 22... Turbine output signal, 23 ...Comparator, 24
···Control device. Agent Patent Attorney Ken Nori Chika Hirofumi Mitamata

Claims (1)

[Claims] In a control device for a nuclear power plant having a main steam relief valve opening means used in conjunction with a partial capacity bypass device for processing surplus turbine supply steam when a generator load suddenly decreases,
A nuclear power plant comprising means for activating a pool water cooling device in a pressure suppression chamber of a residual heat removal system by a deviation signal energizing opening of the main steam relief valve based on a comparative difference between a generator output signal and a turbine output signal. control device.