JPS59107293A - Reactor isolation cooling system - 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 boiling water nuclear reactor (hereinafter referred to as BVI/R), and particularly to a reactor isolation cooling system.

[Technical background of the invention]

Generally, a BWR is provided with a water supply system that supplies cooling water into the reactor pressure vessel. For example, if water supply from this water supply system is stopped, the reactor is isolated. In order to cool the reactor core and maintain the reactor water level during such reactor isolation, a reactor isolation cooling system (hereinafter referred to as the RCIC system) is installed.
is installed. That is, the structure is such that steam generated by the decay heat of the nuclear reactor is used as power to drive a turbine, and a turbine-driven pump directly connected to the turbine is driven to supply cooling water into the reactor pressure vessel.

The RCIC system control device is constructed as shown in FIG. In the figure, 1 indicates a flow rate controller.

The flow rate controller 1 is provided with a manual setting dial 2 and is configured to set a target flow rate using the manual setting dial 2. The flow rate controller 1 then calculates the deviation between the actual flow rate signal from the flow rate detector 5 provided in the discharge pipe 4 of the turbine-driven pump 3 and the target value set by the manual adjustment dial 2, and outputs a signal IS. do. This signal IS
is input to the governor circuit 7 via the switching circuit 6. With this, the opening degree of the turbine control valve 8 is adjusted and the rotational speed of the turbine 9 is controlled. The control device is also provided with a test signal generator 10. This can be done by adjusting the manual setting dial 2 of the flow rate controller 1 as appropriate.
Although it is possible to perform a good test, if the test is not returned to the rated position after the test and normal operation is started at a setting higher than the rated position, there is a risk of adverse effects on the plant. be. In order to prevent such accidents, the configuration is such that a test signal generator 10 exclusively used for testing is provided. Then, the test signal generator 1o outputs a test signal to the governor circuit 7, which changes the opening degree of the turbine control valve 8 appropriately, thereby controlling the turbine 9 from startup to rated operation to stop. It is configured to perform a series of tests. Furthermore, this test signal generator 1o
In order to conduct the flow rate test after switching the switching circuit 6, the flow rate controller 1 side is disconnected.

[Problems with background technology]

According to the above configuration, the flow rate controller 1 is separated during the test, making it impossible to check the necessary flow rate control and dynamic response at startup, and there is a risk that a highly reliable test cannot be performed. .

[Purpose of the invention]

The purpose of the present invention is to be able to confirm the necessary flow rate control and dynamic response at start-up even when conducting tests, and to improve the reliability of tests from start-up to stoppage of turbines and turbine-driven pumps. The object of the present invention is to provide a cooling system for nuclear reactor isolation that can achieve a high level of performance.

[Summary of the invention]

The reactor isolation cooling system according to the present invention uses surplus steam from the reactor to drive a turbine and a turbine-driven pump connected to the turbine to inject cooling water into the reactor pressure vessel. In the cooling system,
A flow rate detector installed in the discharge piping of the turbine-driven bong, a flow rate controller that inputs the detection signal of this flow rate detector and outputs a flow rate control signal, and a test signal generator that outputs a test signal. and a quotient value priority circuit which inputs the test signal from the test signal generator and the flow rate control signal from the flow rate controller and selects and outputs a signal with a high value.

That is, during a test, signals from both the test signal generator and the flow rate controller are input to the high value priority circuit. For example, from the time of startup to the rated value, the signal tl from the test signal generator is set to 0, and the test is performed using the signal from the flow rate controller.

When performing a test that exceeds the rated value, a test signal that exceeds the rated value is output from the test signal generator. As a result, the high value priority circuit selects the test signal. This allows the configuration to perform tests that exceed the rating.

Therefore, when conducting tests, it is possible to perform tests without disconnecting the flow control device side, and it is possible to check reliable flow control and dynamic response at startup, making it possible to perform highly reliable tests. This can significantly improve the safety of Sibrant.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIGS. 2 and 3. In the figure, 101 indicates a reactor pressure vessel. Cooling water 102 is contained within this reactor pressure vessel 101 .

Further, a reactor core 103 composed of a plurality of fuel assemblies, control rods, etc. is accommodated within the reactor pressure vessel 101. The cooling water 102 rises from the bottom to the top of the reactor core 103, at which time its temperature increases and becomes a two-phase flow of water and steam. The two-phase cooling water 102 is separated into water and steam by a steam separator (not shown). The separated steam is then dried in a steam dryer (not shown) to become dry steam and sent to the turbine system via a main steam pipe (not shown). - The power water is configured to descend inside the reactor pressure vessel 10 and repeat the above-described operation.

A reactor isolation cooling system (hereinafter referred to as RCIC system) 104 is connected to the reactor pressure vessel 101 . That is, for example, when the water supply from the water supply system to the inside of the reactor pressure vessel 10 is stopped, the reactor is isolated. At this time, the RCIC system lθ4 is configured to supply cooling water 102 into the multi-reactor pressure vessel 101 to maintain the reactor water level and cool the reactor core 103. The RCIC system 104 includes a steam supply pipe 106 that introduces surplus steam 105 generated by decay heat during reactor isolation, a turbine 107 connected to this steam supply pipe 106, and a turbine connected to this turbine 107. Drive Δ? a water supply pipe 1 disposed between the condensate storage tank 109 and the reactor pressure vessel 10' via the turbine-driven pump 108;
It consists of 10. The steam supply pipe 106 is connected from the reactor pressure vessel 10 side to the turbine population valve 11,
A turbine control valve 112 is inserted. A flow rate detector 113 and on-off valves 114 and 115 are inserted into the water supply pipe 110 from the turbine-driven pump 108 side. Further, a test pipe 116 is provided between the condensate storage tank 109, the flow rate detector 113, and the on-off valve 114. A flow rate detector 11 is installed in this test pipe 116.
Test flow control valves 117 and 118 are inserted from the 3rd side.

In addition, a flow rate controller 119Vi is shown in the figure. This flow rate controller 119 is provided with a dial 120 for setting the flow rate, and by operating the dial 120 on the toilet, the flow rate l:
It has a configuration that allows you to set. The flow rate controller 119 also outputs the detection signal 11 of the flow rate detector 113.
3S is input and control signals 11-98 are output. Further, 121 in the figure indicates a test signal generator. This test signal generator 121 has a power on switch 122.
A power source 123 is connected via the power source 123. The test signal generator 12 outputs a test signal 121S. The test signal 121S and the control signal 119S are input to a high value priority circuit 124. Then, this high value priority circuit 124 selects the signal with the higher output of the above two input signals and contacts 1.
The configuration is such that the output is output to the turbine governor 126 via 25. The 125 contacts are configured to close when a start command for the RCIC system 104 is output. The turbine governor 126 then outputs a signal to the turbine regulator valve 112, whereby the opening degree of the turbine regulator valve 112 is adjusted. Then, the rotational speed is adjusted according to the amount of steam supplied to the turbine 07, and the flow rate is adjusted. There is still a pass circuit 12 in the high value priority circuit 124.
7 is provided, and a contact 128 is inserted. This contact 128 is configured to open when the power supply switch 122 is closed and closed when the power supply switch 122 is opened.

The operation will be explained based on the above configuration. First, during normal operation, the power-on switch 122 is open and the contact 128 is closed. Then, a flow rate signal 1 is set from the flow rate controller 119 to the dial 120.
19S is output to the turbine governor 126 via the bypass circuit 127. Then, a signal 126S is output from the turbine governor 126 to the turbine control valve 112, and the opening degree of the turbine control valve 112 is adjusted. As a result, the amount of steam supplied to the turbine 107 is adjusted, and the amount of steam supplied to the turbine 107 is adjusted.
07 is determined, and the flow rate during normal operation is determined. A flow rate detection signal 113B from the flow rate detector 113 is input to the flow rate controller 119. Then, in the flow rate controller 119, this flow rate detection signal 113S and the dial 120
Controls such as calculating the deviation from the set value set in are performed.

Next, the test will be explained. At this time, the power supply switch 122 of the test signal generator 121 is closed. Closing of the power supply switch 122 opens the contact 128. This shuts off the Binosos circuit 127. The output signal 119S of the flow rate controller 119 and the test signal 121S of the test signal generator 121 are input to the high value priority circuit 124. At this time, the test signal 121
Sf: 0, output signal from flow rate controller 119 1
19S is set to the rated flow rate of the turbine-driven pump 10B, the high value priority circuit 124 outputs the output signal 119S.
Select. Then, for example, the operator selects RC to start the test.
When the activation request signal of the IC system 104 is output, the contact 125 closes, and the turbine governor 126 is connected to the flow rate controller 119.
A flow rate signal 119S from is input. This allows testing from startup to rated flow rate. When the test up to the rated flow rate of the turbine drive pore f10g is completed, the test signal 1 of the test signal generator 12 is
Set 21S above the rated flow rate. As a result, the high value priority circuit 124 changes over time in the output signal of the high value priority circuit 124 as shown in FIG. That is, at the start of the test (10 o'clock in the figure), the output signal corresponds to the rated rotation speed (S, in the figure) K of the turbine 107. Then, as the rotational speed gradually increases, the output signal becomes smaller and reaches the rated rotational speed, and becomes 0 at 4 (at 11 o'clock in the figure). Next, when the test signal generator 121 outputs a test signal 121S that is higher than the rated value (time T! in the figure), a set signal (81 in the figure) that is higher than the rated value is output as shown in the figure. °-゛ Then, the test signal 121S is input to the turbine governor 126, and the turbine 107 has a rotation speed higher than the rated speed. Then, for example, a test is performed to determine whether the turbine 107 stops in order to maintain its health when a predetermined rotational speed is reached. As described above, tests from startup to rated operation to operation at or above the company's rating can be performed without disconnecting the flow rate controller 119 side. According to the above configuration in this series of tests, the test can be performed without disconnecting the flow rate controller 119, and the required flow rate control and dynamic response at startup can be confirmed and reliable. It is possible to perform highly accurate tests.

〔Effect of the invention〕

The reactor isolation cooling system according to the present invention uses surplus steam from the reactor to drive a turbine and a turbine-driven pump connected to the turbine to inject cooling water into the reactor pressure vessel. In the cooling system,
a flow rate detector installed in the discharge pipe of the turbine-driven pump; a flow rate controller that inputs the detection signal of the flow rate detector and outputs a flow rate control signal; and a test signal generator that outputs a test signal. The configuration includes a high value priority circuit which inputs the test signal from the test signal generator and the flow rate control signal from the flow rate controller, selects and outputs a signal with a high value.

That is, during a test, signals from both the test signal generator and the flow rate controller are input to the high value priority circuit. For example, from the time of startup to the rating, the signal #1 from the test signal generator is set to 0, and the test is performed using the signal from the flow rate controller.

When performing a test that exceeds the rating, the test signal generator outputs a test signal that exceeds the rating. This causes the high value priority circuit to select the test signal. This is K
Therefore, it is configured to perform tests exceeding the rating.

Therefore, the test can be performed without disconnecting the flow controller side, and the necessary flow control and dynamic response at startup can be confirmed, making it possible to perform highly reliable tests. This has great effects, such as significantly improving the safety of the plant.

[Brief explanation of drawings]

Figure 1 is a diagram showing a conventional example and is a system diagram showing part of the configuration of the reactor isolation cooling system, and Figures 2 and 3 are diagrams showing an embodiment of the present invention. System diagram of isolation cooling system,
FIG. 3 is a diagram showing temporal changes in the output signal from the high value priority circuit. 10... Reactor pressure vessel, 102... Cooling water, 1
04...Reactor isolation cooling system, 105...Excess steam, 108...Turbine drive pump, 113...Flow rate detector, 119...Flow rate controller, 121...Test signal Generator, 124...High value priority circuit.

Claims (2)

[Claims] (1) In a reactor isolation cooling system in which cooling water is injected into the reactor pressure vessel by driving a turbine and a turbine-driven pump connected to the turbine using surplus steam of the reactor during reactor isolation, the turbine-driven pump is a flow rate detector installed in the discharge piping of the test system, a flow rate controller that inputs the detection signal of this flow rate detector and outputs a flow rate control signal, a test signal generator that outputs a test signal, and a test signal generator that outputs a test signal. A reactor isolation cooling system characterized by comprising a high value priority circuit which inputs a test signal from a signal generator and a flow control signal from the flow rate controller and selects and outputs a signal with a high value. . (2) The high value priority circuit is provided with a bypass circuit, and the flow rate control signal from the flow rate controller is outputted through this 24791 circuit at times other than when testing. The reactor isolation cooling system described in item 1.