JPS622280B2 - - Google Patents

Description

[Detailed Description of the Invention] (1) Field of Application of the Invention The present invention is directed to the application of treated water to a waste liquid source system in a centralized waste liquid treatment system that centrally processes waste liquid from a plurality of waste liquid generating systems. This concerns the return method. In order to simplify the explanation, a nuclear power plant will be used as an example, that is, a BWR power generation unit will be used as a waste liquid generation system, and a radioactive waste centralized treatment system will be used as an example of a centralized waste liquid treatment system.

(2) Prior Art Conventionally, in a BWR nuclear power plant, each power generation unit is equipped with one radioactive waste treatment system that processes and recovers radioactive waste fluid generated from the power generation unit. The waste liquid is treated and recovered to reduce the radioactivity released and used again in the power generation unit. Recently, plans have been made to collectively process the radioactive waste fluids (hereinafter simply referred to as waste fluids) from multiple power generation units in order to streamline operations and downsize the equipment. In such a centralized waste liquid treatment system, care must be taken not to increase or decrease the amount of water held in each power generating unit when returning and recovering the treated water to the power generating units after treating the waste liquid. Must be. If the amount of water held within the power generation unit increases, surplus water will be generated and it will be necessary to release the surplus water to the outside of the system, resulting in an increase in radioactivity released to the outside of the system. Conversely, when the amount of water held in the power generation unit decreases, water will be taken in from outside the system, which will lead to an increase in the amount of water held in the power plant as a whole, resulting in surplus water and radioactivity released outside the system. To increase.

In the case of a conventional plant configuration with one power generation unit and one radioactive waste treatment system,
Treated water always automatically returns to the original power generation unit, but in the case of a centralized wastewater treatment system, the amount of wastewater generated and the amount of returned treated water is monitored for each power generation unit, and the treated water is It is necessary to control the return destination. Although it is possible to have the operator of the operating waste liquid treatment system switch the return destination of treated water in accordance with the amount of waste liquid generated by each power generation unit, this increases the amount of work and is not preferable.

(3) Purpose of the Invention The object of the present invention is to provide a treated water return control method that automatically controls the return of treated water without increasing or decreasing the amount of water held in each power generation unit as much as possible.

(4) General explanation of the invention For this reason, in the present invention, the amount of waste liquid generated from each power generation unit and the amount of treated water returned to the power generation unit are measured by the flow rate meter, the tank level meter, the pump operating time, and the amount of water returned to the power generation unit. The difference between the amount of waste liquid generated and the amount of returned treated water is memorized, and the treated water is returned preferentially to the power generation unit with the largest difference. In addition, the water level of the receiving tank where the treated water is transported is monitored, and depending on the water level, the
By switching the destination of treated water return to the power generation unit with the next largest difference between the amount of waste liquid generated and the amount of returned treated water, overflow of the receiving tank of treated water is prevented.

By doing so, the difference between the amount of waste liquid generated and the amount of returned treated water for each power generation unit can be averaged. Furthermore, from the perspective of each power generation unit, the difference between the amount of water transported to the waste liquid centralized treatment system and the amount of treated water returned is controlled to be small, so the amount of water held in each power generation unit increases or decreases. It becomes less.

(5) Examples Hereinafter, the present invention will be explained in detail with reference to examples. FIG. 1 is a diagram showing an embodiment of the present invention, in which there are four power generation units.
In Fig. 1, 1 is a power generation unit, 2 is a waste liquid transport pump, 3 is a waste liquid transport pipe, 4 is a waste liquid integrated flow meter, and 5 is a waste liquid transport pump.
is a waste liquid receiving tank, 6 is a waste liquid central processing system,
7 is a treated water storage tank, 8 is a treated water transport pump,
9 is a treated water switching valve, 10 is a treated water integrated flow meter, 1
1 is a treated water transport pipe, 12 is a treated water switching valve control device, 13 is a treated water receiving tank, and 14 is a treated water receiving tank water level gauge.

The waste liquid generated in each power generation unit 1 is sent to a waste liquid receiving tank 5 through a waste liquid transport pipe 3 by a waste liquid transport pump. The waste liquid collected in the waste liquid receiving tank 5 is filtered and concentrated by the waste liquid concentration system 6.
The water is treated with desalination, etc., and collected in the treated water storage tank 7 as treated water that can be reused in the power generation unit.
Treated water transport pipe 11 by treated water transport pump 8
through the treated water receiving tank 13 of each power generation unit 1
will be returned to. At this time, switching of the power generation unit 1 to which the treated water is to be transported is performed by the treated water switching valve 9 controlled by the treated water switching control device 12. The waste liquid integrating flow meter 4 attached to the waste liquid transport pipe 3 and the treated water integrating flow meter 10 attached to the treated water transport pipe 11 measure the amount of waste liquid transported and the amount of treated water transported for each power generation unit, respectively.
Transport amount data is sent to the processing water cutoff valve control device 12.
The treated water switching valve control device 12 includes a waste liquid integrated flow meter 4
The return destination of the treated water is determined based on the difference between the total flow rate meter 10 and the treated water integrated flow meter 10. On the other hand, the treated water switching valve control device 12
Now, the treated water receiving tank 1 in each power generation unit 1
The data from the treated water receiving tank water level meter 14 of No. 3 is received, and a check is made to see if it is possible to return the treated water determined by the above method. If it is not possible, then the waste liquid integrated flow meter 4 and the treated water integrated flow meter The treated water switching valve 9 is controlled so that the treated water is returned to the power generation unit with a large difference in the number of units.

FIG. 2 shows an embodiment of the treated water switching valve control device 12. 15 is an adder, 16 is a flow rate comparator, 1
7 is an AND gate, 18 is a water level comparator, and 19 is a signal generator. The difference between the waste liquid integrated flow meter 4 and the treated water integrated flow meter 10 is calculated by an adder 15. In addition,
The operation of the signal generator 19 will be described later, but
Normal output is 0. The outputs of the adder 15 are compared by the flow rate comparator 16, and the output corresponding to the power generation unit with the largest difference is set to 1. Other outputs are 0. On the other hand, the signal from the treated water receiving tank water level meter 14 of the treated water receiving tank 13 of each power generation unit 1 is compared with the voltage at the high water level designated for each treated water receiving tank by the water level comparator 18. FIG. 3 shows the input/output relationship of the water level comparator 18. If the water level in the treated water receiving tank 13 is below the water level high level, 0 is output, and if it is above, 1 is output. In addition, in order to avoid vibrations in the output of the treated water switching valve control device 12, once the water level in the treated water receiving tank 13 reaches the high water level, the output of the water level comparator 18 is kept at 1 until the water level drops to a certain level. It is designed to remain as it is. The output of the water level comparator 18 enters the signal generator 19, and the output of the water level comparator 18 becomes 0.
If the output of the signal generator 19 is 0, and if the output of the water level comparator 18 is 1, the output of the signal generator 19 is sufficient compared to the difference between the amount of collected waste liquid and the amount of returned treated water. A signal corresponding to a larger value is output, respectively. The output of the signal generator 19 is input to the adder 15, and when the water level of the treated water receiving tank 13 is high, the output of the signal generator 19 is input to the waste liquid integrated flow meter 4 and the treated water integrated flow meter 10.
An even larger value is subtracted from the difference between
The output of the adder 15 becomes a small value compared to the others, so that the treated water is not returned to the corresponding power generation unit. Further, since the flow rate comparator 16 selects the one with the larger output from the adder 15, the difference between the waste liquid integrated flow meter 4 and the treated water integrated flow meter 10 is large and the water level in the treated water receiving tank 13 is not at a high water level. The power generation unit 1 is designated as the destination of the treated water. Note that the inverted output of the water level comparator 18 and the output of the flow rate comparator 16 are connected to the AND gate 17.
A logical OR is performed, and an interlock is established separately from the above system so that the water level in the treated water receiving tank 13 does not exceed the water level high level.

In addition, in the above embodiment, the number of power generation units is 4.
Although the present invention has been described for the case of one power generation unit, it goes without saying that the present invention can also be applied to systems having other numbers of power generation units. Further, in order to simplify the explanation, the explanation has been given using a nuclear power plant as an example, but the present invention can also be applied to other waste liquid treatment systems. Further, the control device shown in the embodiment of the present invention can perform similar operations by simulating the operations of each device using a computer.

(6) Summary As explained above, according to the present invention, (1) After collecting and processing waste liquids from systems that generate multiple waste liquids at once, the treated water is collected in the system that generated each waste liquid in an amount corresponding to the amount of waste liquid collected. Only items can be returned automatically.

(2) Collection of waste liquid and return of treated water do not increase or decrease the amount of water held in each system, and prevent the generation of surplus water due to increase or decrease in the amount of held water and the resulting release of hazardous waste liquid outside the system. I can do it.

(3) When returning treated water, the water level in the tank on the receiving side of treated water is measured, and if the tank is full, the treated water is returned to the next highest priority destination. Prevents water tank overflow.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of a treated water switching valve control device, and FIG. 3 is a diagram showing an input/output relationship of a water level comparator. 1...Power generation unit, 4...Waste liquid integrated flow meter,
9... Treated water switching valve, 10... Treated water integrated flow meter, 12... Treated water switching valve control device, 14... Treated water receiving tank water level gauge.

Claims (1)

[Claims] 1 Processed water return in which waste liquid from multiple waste liquid generation source systems that generate waste liquid is treated all at once, and the treated treated water is returned to the above-mentioned multiple waste liquid generation source systems as water to be reused in the waste liquid generation source system. In the control method, the amount of waste fluid generated from the waste fluid generation source system and the amount of treated water returned to the waste fluid generation source system are measured for each waste fluid generation source system, and the difference between the measured amount of waste fluid generated and the amount of returned treated water is determined. A method for controlling the return of treated water in a centralized waste liquid treatment system, characterized in that treated water is returned preferentially to a waste liquid generation source system with a large amount of waste liquid.