JPS608476B2 - Filter control device in radioactive waste treatment system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filter control device, and more particularly to a filter control device suitable for controlling a filter for purifying waste liquid in a radioactive waste treatment system of a nuclear power plant.

Traditionally, a filter has been used as a purification device for waste liquid in the radioactive waste treatment system of a nuclear power plant. Therefore, constant flow rate control is performed.

In addition, a differential pressure gauge is installed at the entrance and exit of the filter as a device to detect clogging of the filter agent, and by comparing the differential pressure value with a certain set value, clogging is detected and the filter agent is regenerated. Is going. However, such conventional control methods have the following problems.

First of all, when controlling the flow rate, it is important to note that if only the normal constant flow rate control of the liquid supply flow rate is used, the flow control valve will be fully open when the pump is stopped, so a sudden flow will occur when the pump is started, and solid impurities captured in the filter medium will be liberated. In order to solve this problem, it may be possible to install a recirculation line at the filter outlet and run the recirculation line for a certain period of time after the pump is started, but the operation time will be extended. "It has the disadvantage of reducing operating efficiency. On the other hand, if the flow rate fluctuates when detecting blockage in the filter, the differential pressure value will change depending on the flow rate, so detecting blockage at a fixed value is appropriate. Therefore, in the past, the filter medium was often replaced before the differential pressure value reached a certain set value, resulting in the generation of used filter medium containing radioactivity. Therefore, the present invention was made in view of the problems of the above-mentioned conventional technology, and its purpose is to stop the pump in order to prevent the rush of flow when starting the pump. At times, the flow control valve is fully closed, and when the pump is started, the flow control valve is controlled to gradually open. At the same time, filter agent blockage is detected using a differential pressure value corrected by the flow rate value, thereby ensuring proper blockage detection. An object of the present invention is to provide a filter control device capable of regenerating a filter medium by performing the following steps.

The filter control device of the present invention will be explained in more detail below with reference to the drawings.

FIG. 1 is a block diagram of a 3-tatami filter control system according to an embodiment of the present invention, in which 1 is a pump for introducing radioactive waste liquid, 5 is an outlet pipe of the pump 1, and 2 is the pump. 3 is a flow rate control valve; 4 is a filter for filtering radioactive waste liquid; 8 is a ramp function generator that outputs a ramp function signal 14 based on the starting signal 22 of pump 1; 9 is a manual setting device for manually setting the flow rate and generating a flow rate setting signal 5; 6 is the ramp function signal blade 4;
and the flow rate setting signal 15 and outputs the lower value as the control signal 16; 7 is a control signal 52 from the flow meter 2 and the low value priority circuit 6; a flow rate controller that controls the flow rate control valve 3 by matching signals 16; 13 is a filter medium regenerator connected to the filter 4 via piping 26; i2 is a pressure difference between the inlet and outlet of the filter 4; A differential pressure meter that detects and outputs a differential pressure signal 9, and a blade 1 input the output signal 18 of the flow meter 2 and the differential pressure signal 9, and a multiplication/division calculator 20' that performs multiplication and division operations. This is a differential pressure setting device which receives the output signal 21 of the device 11 and gives a signal 25 to the agent regenerating device [3].

As is clear from FIG. 1, the radioactive waste liquid is supplied to the filter vessel 4 via the pump river, the outlet pipe 5, the flow meter 2 and the flow control valve 3.The output signal 52 of the flow meter 2 is It is connected to the flow rate regulator 7.The flow rate regulator hole is connected to the control signal from the low value priority circuit 6, and its output signal 17 is also connected to the flow rate control valve 3. A ramp function signal 4 from a ramp function generator 8 and a flow rate setting signal 15 from a manual setting device 9 are connected to the low value priority circuit 6. A start signal is input to the filter 4.
A differential pressure gauge turtle 2 is provided between the entrance and exit of the differential pressure gauge turtle 2, and its output, a differential pressure signal turtle 9, is connected to a multiplication/division arithmetic unit. The multiplication/division calculator 111 receives the output signal 8 from the flowmeter 2.
is input, and the output signal between the two rivers and the differential pressure setting device 28
Furthermore, the output signal 25 of the differential pressure setting device 2 is connected to the filter medium regenerating device 13. The agent regenerating device 3 is connected to the filter 4 through a pipe 2. In such a configuration, its operation is shown in Figure 2 a and c.
, a, e and FIG. 3.

By the way, FIG. 2a shows the output signal after the pump of the ramp function generator 8 is activated, that is, the ramp function signal after the pump is started.
Figure b' shows the flow rate setting signal of the manual setting device 9, and Figure 2 c
2 is a characteristic diagram showing the output signal group 6 of the low value priority circuit 6, FIG. 2 d is a characteristic diagram showing the valve function of the flow rate control valve 3, and FIG. 3 is a characteristic diagram showing the relationship between the flow rate of the liquid supplied to the filter 4 and the differential pressure. Now, when the pump 1 is started, the ramp function generator 8 is operated by the signal 22 at the same time as the start-up. The ramp function signal wing 4 is input to the low value priority circuit 6 with a waveform as shown in FIG. 2a.

On the other hand, the flow rate setting signal 15 from the manual setting device 9 is input to the low value priority circuit 6 at a constant value as shown in FIG. 2b. The low value priority circuit 6 compares the signal 14 from the ramp function generator 8 and the signal i5 from the manual setting device 9, and selects the signal with the lower value as the low value signal 16. The waveform shown in Figure 2c is output to the flow rate controller 7.As a result, the flow rate controller 7 uses the signal 16 from the low value priority circuit 6 as the target value, and the flow rate signal 52 from the flow meter 2 as the target value. In order to adjust the flow rate control valve 3 so as to match the flow rate, the flow rate control valve S is controlled as shown in FIG. The liquid supply flow rate gradually increases as the ramp function signal Kamegawa approaches. After that (see Figure c), the flow rate is controlled to a constant flow rate preset in the manual setting device 9. As a result, the second
Figure e shows the change in water supply flow rate.

For this reason, it is possible to start operation without generating a rush flow in the filter.On the other hand, the multiplier/division calculator has a differential pressure meter 2 installed between the entrance and exit of the filter. The differential pressure signal packet 9 is input, and at the same time, the flow rate signal 1 from the flow meter 2 installed in the discharge pipe of the pump is also input.

The multiplication/division operator neck receives the differential pressure signal 1 from the differential pressure measurement 2.
9 is corrected to the differential pressure value at the reference flow rate using the output signal of the flowmeter 2. The differential pressure value corrected to the value at the reference flow rate by the multiplier/divider group W is input to the hair pressure setting device cloud 0. The differential pressure setting device 2M detects that the input signal exceeds a certain value and sends a signal 2 to the filter medium regeneration device turtle 3.
However, upon receiving this signal 2, the filter medium regenerating device 3 regenerates the filter medium through the pipe 28.
By the way, methods for regenerating the filter agent include backwashing by applying back pressure and replacing the filter agent itself, but any method can be used depending on the structure of the filter. , since the filter 4 is detected to be clogged by the pressure value obtained by correcting the vertical liquid flow rate to the filter 4 to the standard flow rate, when the operation is performed at a liquid supply flow rate higher than the standard flow rate, the differential pressure gauge as shown in Fig. 3 is detected. As the output signal from oven 2 becomes larger, it can cause ``filter regeneration to start even though no clogging has actually occurred,'' or ``on the contrary, if the operation is performed at a liquid supply flow rate lower than the standard flow rate, a blockage may occur.'' This eliminates the inconvenience of not being able to detect the clog even though it is clogged, and the filter medium of the filter 4 can be regenerated by properly detecting the clog.

As stated above, ``According to the present invention, when the filter starts operating, the flow rate of liquid supplied to the filter is controlled to increase in a ramp-like manner to prevent a sudden flow, and after a certain period of time after the start of operation, the operator can set By setting the liquid supply flow rate to a constant value, it is possible to prevent the release of solid impurities captured in the filter medium and also to detect clogging of the filter according to the liquid supply flow rate set by the operator. By doing so, it is possible to prevent an increase in the amount of used filter media generated due to unnecessary agent regeneration and a decrease in processing efficiency due to continued operation despite clogging. It is possible to obtain a filter control device that makes it possible to appropriately control the operation of a filter in a waste treatment system.

[Brief explanation of the drawing]

Figure 2 is a block diagram of a filter control device according to an embodiment of the present invention, Figure 3 is a characteristic diagram explaining the operation of the mechanism. ...flow meter, 3...flow control valve "
Mother...Filter 7...Flow rate controller, 8...
・...Function generator, 12...Differential pressure gauge. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A filter that purifies waste liquid from a radioactive waste treatment system of a nuclear power plant, a filter medium regeneration device that regenerates the filter medium of this filter, and supplies the waste liquid to the filter. pump and
A flow meter attached to the discharge side piping of this pump, a flow control valve that inputs the output signal of this flow meter to control the flow rate of liquid supplied to the filter, and an opening degree of this flow control valve. a flow rate controller that outputs a signal for adjustment, and a flow rate setting adjustment circuit that supplies the flow rate controller with a set value that increases in a ramp-like manner for a certain period of time after the pump starts operating, and then a constant set value. , a differential pressure gauge that measures the differential pressure between the inlet and outlet of the filter, and a differential pressure value obtained by correcting the output signal of this differential pressure gauge with the output signal of the flowmeter, which detects when the differential pressure value exceeds a certain value. A filter control device in a radioactive waste treatment system, comprising: a differential pressure setting adjustment circuit that detects and issues an output signal to the filter medium regeneration device. 2. The flow rate setting adjustment circuit includes a ramp function generator that starts operation after operation of the pump, a manual setting device for setting a constant setting value, and output signals of both the ramp function generator and the manual setting device. and a low value priority circuit that gives priority to low values and supplies the priority signal to the flow rate controller. Control device. 3 The differential pressure setting adjustment circuit includes a multiplier/divider that corrects the output signal of the differential pressure gauge to a differential pressure value at a reference flow rate based on the output signal of the flow meter, and a multiplier/divider that corrects the output signal of the differential pressure gauge to a differential pressure value at a reference flow rate, and a A filter in a radioactive waste treatment system according to claim 1, characterized in that the filter is comprised of a differential pressure setting device that detects this when the filter medium regenerates and issues an output signal to the filter medium regenerating device. Control device.