JPS6238398A - Pressure controller for 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 invention].

The present invention relates to a reactor pressure control device for a boiling water nuclear reactor during reactor isolation.

[Technical background of the invention]

A reactor pressure control system for a conventional boiling water nuclear reactor will be explained with reference to FIG.

The steam generated in the reactor pressure vessel 1 is transferred to the main steam pipe 2,
The steam is guided to the steam turbine 6 through a main steam isolation valve 3, a main steam stop valve 4, and a main steam control valve 5, which are connected in series thereto.
Here, the steam whose thermal energy is converted into mechanical power enters the main condenser 7 and is cooled with seawater to become condensed water, which is sent to the reactor pressure vessel 1 again by the water supply pump 8. Now, when the main steam isolation valve 3 closes for some reason during the steady operation of the reactor, and the reactor with pressure vessel 1 is isolated and scrammed, the reactor with the passage to the steam turbine 6 closed. The steam generated in the pressure vessel 1 is caused to rapidly increase the reactor pressure. (The blowout setting pressure of the main steam relief valve 10 (only one is shown in the figure) is reached. Then, this main steam relief valve 1
The steam that has passed through the reactor pressure vessel 1 is guided into the water of the pressure suppression pool 11 into which one end of the branch steam pipe 9a is inserted and condensed, thereby suppressing the increase in the pressure inside the reactor pressure vessel 1. The main steam relief valve 1o is then closed.

However, if the decay heat within the reactor pressure vessel 1 is large, steam is generated within the reactor pressure vessel 1 even after the reactor scram, and the pressure within the reactor pressure vessel 1 continues to rise. Therefore, the pressure inside the reactor pressure vessel 1 reaches the blowout setting pressure l of the main steam relief valve io again, the main steam relief valve 10 opens, and the steam inside the reactor pressure vessel 1 is released into the pressure suppression pool 11. The pressure within the reactor pressure vessel 1 is lowered. At this time, since the amount of steam blown out from the main steam relief valve 1° is larger than the amount of steam generated after the reactor scram, the pressure inside the reactor pressure vessel 1 drops rapidly when the main steam relief valve 1° is opened. , the main steam relief valve 10 will close again.

Normally, the reactor pressure is adjusted by intermittent opening and closing of the main steam relief valve 10 as described above.

[Problems with background technology]

In the conventional reactor pressure control system as described above, the water level inside the reactor pressure vessel changes suddenly due to the disappearance and creation of voids due to sudden changes in the pressure inside the reactor pressure vessel, and in some cases, the water level inside the reactor pressure vessel changes suddenly due to the high water level inside the reactor pressure vessel. , feed water pumps, reactor isolation cooling pumps, etc. may trip unnecessarily. Another disadvantage is that the intermittent opening and closing of the main steam relief valve causes meaningless mechanical shock to related parts.

CObject of the Invention] - This invention was made to solve the above-mentioned problems in the conventional reactor pressure control device, and it is possible to continuously control the reactor pressure during reactor isolation. The purpose is to provide a nuclear reactor pressure control device that can

[Summary of the invention]

A nuclear reactor pressure control device according to the present invention includes a main steam pipe connecting a reactor pressure vessel and a steam turbine with a main steam isolation valve connected therebetween, and a main steam pipe connecting a reactor pressure vessel and a steam turbine;
In addition to the above configuration of a conventional reactor pressure control VC system, which has a branch steam pipe connected to a main steam relief valve in the middle and whose end opens into a pressure suppression pool, A side steam pipe that flows to the side of the main steam relief valve, a steam flow rate adjustment valve connected between the side steam pipes, a reactor pressure detector that detects the steam pressure inside the reactor pressure vessel, and a reactor pressure detector. [Embodiment of the Invention] An embodiment of the invention is described in the first embodiment. The diagram will be explained.

In FIG. 1, parts ζ similar to those shown in FIG. 2 are given the same reference numerals as in FIG.
The foregoing description of FIG. 2 supersedes it.

The nuclear reactor pressure control device according to the present invention has a main steam pipe 2, a main steam isolation valve 3, a branch steam pipe 9b, a main steam relief valve 10, a pressure suppression A pool 11 is provided, and in addition to these, a side steam pipe 12
, a steam flow rate adjustment valve 13, a furnace pressure detector 14, and a controller 15 are additionally provided. The branch steam pipe 9b is the branch steam pipe 9
Although it branches from the main steam pipe 2 in the same way as in a, the branch steam pipe 9b has a side steam pipework 2 that flows sideways through the main steam relief valve 10.
A steam flow rate adjustment valve 13 is connected to the intermediate Cζ of the side steam pipe 12. A reactor pressure detector 14 that detects the steam pressure in the reactor pressure vessel 1 is installed separately, and a separate controller 15 receives a signal from the reactor pressure detector 14 and manually controls the opening of the steam flow rate adjustment valve. and automatic control.

Next, the operation of the nuclear reactor pressure control system according to the present invention configured as described above will be explained.

Now, in a nuclear power plant, when the main steam isolation valve 3 opens for some reason during high-output operation and the reactor with reactor pressure vessel 1 is isolated, the instantaneous situation inside the reactor pressure vessel 1 will be explained. The pressure rise is suppressed by opening the main steam relief valve 10 and introducing the steam in the reactor pressure vessel 1 into the water in the pressure suppression pool 11 where it is condensed.

On the other hand, the reactor pressure detector 14 detects the steam pressure within the reactor pressure vessel 1 and issues a pressure signal thereof. The controller 15 is
Upon receiving the pressure signal output from the furnace pressure detector 14, it compares it with its own preset pressure and controls the opening degree of the steam flow rate regulating valve 13 in a direction that eliminates the difference between the detected pressure and the set pressure.

This opening degree can be controlled either manually or automatically. After the instantaneous pressure increase in the reactor pressure vessel 1 due to the closure of the main steam isolation valve 3 is released by the opening of the main steam relief valve 10, if the controller 15 is set to automatic mode,
Steam generated by decay heat in the reactor pressure vessel 1 is continuously released into the water in the pressure suppression pool 11 via the reactor pressure detector 14 controller 15 and the steam flow rate adjustment valve 13, thereby increasing the reactor pressure. The pressure inside the container 1 is continuously and automatically controlled.

〔Effect of the invention〕

As explained above, the nuclear reactor pressure control device according to the present invention has the structure of a conventional reactor pressure control device having a branch steam pipe connected to a main steam relief valve, and also has a branch steam pipe connected to a main steam relief valve. A side-stream steam pipe with a steam flow rate adjustment valve and a side-stream steam pipe that flows to the side of the main steam relief valve is installed, and a reactor pressure detector that detects the steam pressure inside the reactor pressure vessel and a reactor pressure detector that receives the output signal of the reactor pressure detector are installed. By installing a controller to control the opening degree of the steam flow rate adjustment valve, it is possible to increase the pressure after the instantaneous pressure increase in the reactor pressure vessel due to the closure of the main steam isolation valve is relieved by the opening of the main steam relief valve. The pressure of the steam generated by decay heat in the reactor pressure vessel is detected by a reactor pressure detector, and this detected pressure is compared with the set pressure there in the controller, and the controller compares the detected pressure and the set pressure. By continuously and automatically controlling the opening of the steam flow control valve to eliminate the difference in pressure, the amount of steam released from the reactor pressure vessel to the pressure suppression pool via the steam flow control valve is adjusted. The effect is that the pressure in the reactor pressure vessel is continuously and automatically controlled, and therefore, the pressure in the reactor pressure vessel is adjusted by intermittent opening and closing of the main steam relief valve, as in the conventional reactor pressure control system. This has the effect of avoiding unnecessary trips of the feed water pump and reactor cooling pump during reactor isolation, and of preventing meaningless mechanical shocks given to related parts due to the intermittent opening and closing of the main steam relief valve.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a nuclear reactor pressure control device according to the present invention, and FIG. 2 is a block diagram showing a conventional reactor pressure control device. 1... Reactor pressure vessel, 2... Main steam pipe, 3...
Main steam isolation valve, 6... Steam turbine, 9b... Branch steam pipe, 10... Main steam relief valve, 11... Pressure suppression pool, 12... Side steam pipe, 13... Steam flow rate adjustment valve, 14...Furnace pressure detector, 15...Controller.

Claims (1)

[Claims] a main steam pipe whose one end is connected to the reactor pressure vessel and supplies steam generated in the reactor pressure vessel to the steam turbine; a main steam isolation valve connected in the middle of the main steam pipe; A branch steam pipe that branches between the reactor pressure vessel and the main steam isolation valve, a pressure suppression pool into which the end of the branch steam pipe is open and inserted, and a main steam relief connected to the middle of the branch steam pipe. A reactor pressure control device comprising: a side steam pipe that branches from the branch steam pipe and flows sideways to the main steam relief valve; and a steam flow rate adjustment valve connected to an intermediate portion of the side steam pipe; The reactor pressure detector includes a reactor pressure detector that detects the steam pressure in the reactor pressure vessel, and a controller that automatically controls the opening degree of the steam flow rate regulating valve in response to a signal issued by the reactor pressure detector. A nuclear reactor pressure control device characterized by: