JPH067957B2 - Water supply / condensate purification equipment for nuclear power plants - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a water supply / condensate purification device for a nuclear power plant, which is operated before starting the nuclear power plant.

[Technical background of the invention and its problems] In a nuclear power plant that uses light water as a coolant, for example, in a boiling water nuclear power plant, when starting the power plant after the completion of periodic inspection, an ion exchange resin should be used before starting. Using the condensate purification device that uses, the operation to recirculate and purify the water supply and condensate will be carried out. Corrosion products (hereinafter referred to as clad) that are generated or accumulated during the regular period or during the previous operation cycle due to the purification operation of the water supply / condensate purification device.
Is removed to prevent the cladding from being brought into the reactor after startup.

However, the clad which is corroded or deposited during the periodic inspection or in the previous operation cycle has a large proportion of those having a fine grain size of about 0.1 μm or more. A condensate purifier using an ion exchange resin has poor removal performance and cannot easily reduce the clad concentration. for that reason,
There are drawbacks such as long supply and condensate purification operation time, and because the clad generated in the water supply system passes through the hot well with a slow flow rate until it is removed, sedimentation occurs on the way.

On the other hand, even if the clad can be removed satisfactorily, if the conventional condensate purification device is started without chemical regeneration, a new problem such as an increase in differential pressure due to trapping of the clad or a decrease in the clad removal rate will occur. Occurs. Further, in the case of carrying out the recycle of chemicals, there arises a difficult problem such as a delay in start-up and an increase in secondary waste such as waste liquid for regeneration.

[Object of the Invention] An object of the present invention is to provide a water supply / condensate purification device for a nuclear power plant, which has a small amount of secondary waste with an excellent clad removal rate and can shorten the number of purification operation days.

[Outline of the Invention] A low-pressure condensate pump, a valve, and a condensate purifier using an ion-exchange resin are connected from the hot well of the main condenser, and a high-pressure condensate pump is connected to the lower sulfur side of the condensate purifier. A line that connects the water heater and valve and returns to the main condenser will be provided.
In addition, a water supply / condensate water purifier using a hollow fiber membrane filter is connected via a header branched from the upstream side of the water condensate water purification device, and the downstream side of this water supply / condensation water purification device is connected via an outlet pipe. A line for returning to the hot well of the condenser is provided.
Further, a line is provided that branches from between the condensate purifier and the high-pressure pump and connects a condensate recirculation pipe via a plurality of valves to return to the hot well of the main condenser. A condensate purification pipe and a feedwater purification pipe are connected to the header, the condensate purification pipe is connected between a plurality of valves on the upstream side of the condensate recirculation pipe, and is connected to the feedwater recirculation pipe.

With these piping systems, a hot water purification line, a condensate purification line, and a feed water purification line are connected to a condensate purifier that uses ion-exchange resin through valve switching and a header, and a hollow fiber membrane filter. The used water / condensate purifier can be operated selectively.

By using the hollow fiber membrane filter, almost 100% removal efficiency can be obtained for the clad having a particle size of about 0.1 μm or more.

[Embodiment of the Invention] The present invention will be described with reference to each embodiment shown in FIG. 1, FIG. 2 and FIG. First, in the embodiment shown in FIG.
The main condensers 1, 2, and 3 of the nuclear power plant are provided with hot wheels 1A, 1B, 2A, 2B and 3A, 3B, respectively. Each hot well 1A-3
The condensate of B is sent to the condensate purifier 5 using the ion exchange resin by the low-pressure condensate pump 4, and further to the water supply heater 7 by the high-pressure condensate pump 6, and then supplied as a water supply recirculation pipe 8 From each hot well 1A ~
Return to 2B.

Therefore, in the present invention, in addition to the condensate purifier 5, the water supply / condensate purifier 10 using the non-filtering aid type hollow fiber membrane filter 9 is also used in the above water supply / condensate system. The hollow fiber membrane filter 9 is made of polyethylene or the like in the form of a hollow fiber membrane, and the hollow fiber membrane has fine pores communicating with the inside and outside, and these fine pores exert a function of a filter action. It is a thing. The present inventors have found that most of the particle size of the clad is 0.1 μm or more, and the fine pores of the hollow fiber membrane filter 9 are fine pores of about 0.1 μm. Almost 1 for clad
It has been confirmed that the removal rate is 00%.

The water supply / condensate water purifier 10 using the hollow fiber membrane filter 9
The outlet pipe 11 is connected to the hot wells 1A, 1B, 2A, 2B and 3 of the respective main condensers 1, 2 and 3 respectively.
It is provided in the water supply / condensation system by connecting to A and 3B and connecting the inlet pipe 12 to the header 13. That is, the header 13 is connected to the upstream side of the valve V ₁ provided between the low pressure condensate pump 4 and the condensate purifier 5 via the valve V ₂ by the hot well purification pipe 14. In addition, the hot well 1A of the main condenser 1 and the upstream side of the high-pressure condensate pump 6
A valve V _{4 of} the condensate recirculation pipe 15 connecting between
It is connected to the valve V ₇ via a condensate purification pipe 16. Further, the feed water recirculation pipe 8 connecting the feed water heater 7 and the main condenser 1 is connected to the upstream side of the valve V _{6 by} the feed water purification pipe 17 via the valve V ₅ . Further, the condensate purifier 5 is provided with a bypass pipe 18 having a valve V ₃ .

Next, the purifying operation of the water supply / condensate purifying apparatus of the nuclear power plant according to the present invention configured as described above will be described. The purification operation before the start of the power plant selectively passes through the lines passing through the hot well purification pipe 14, the condensate purification pipe 16 and the feed water purification pipe 17 in FIG. ₁ by controlling the valves V _{1 to} V _7. It is done by pouring water.

When purifying the hot well, valves V ₁ , V
₄ , V ₇ , V ₅ and V ₆ are closed and valve V ₂ is opened. When the low-pressure condensate pump 4 is started, the condensate in each hot well is sent from the hot well purification pipe 14 through the header 13 and the inlet pipe 12 into the water supply / condensate purifier 10, and the hollow fiber membrane After being purified by the efficient purification action of the filter 9, the hot wells 1A, 1 of the respective main condensers 1, 2 and 3 are discharged from the outlet pipe 11 respectively.
B, 2A, 2B and 3A, 3B. By operating the above purification line, the purification of the hot well of the main condenser can be completed in a short time.

Next, when purifying the condensate system line, the valves V ₂ , V ₅ and V ₆ are closed and the valves V ₁ and V ₄ are opened. When the low-pressure condensate pump 4 is started, the condensate in the hot well passes through the condensate purifier 5 using an ion exchange resin, from the condensate purification pipe 16 to the header 13 and the inlet pipe 12.
It is sent to the water supply / condensate purifier 10 using the hollow fiber membrane filter 9 and is purified there, and is then purified from the outlet pipe 11 in the hot well of each of the main condensers 1, 2 and 3. Returned to. Further, by opening the valve V ₃ , the bypass pipe 18 is utilized to bypass the condensate purifier 5 using an ion exchange resin, and the hollow fiber membrane filter 9 is used.
It is also possible to purify only with the water supply / condensate purifier 10 using.

When further purifying the water supply system line, use the valve V
₂ , V ₄ and V ₇ are closed and valve V ₅ is opened. When the low-pressure condensate pump 4 and the high-pressure condensate pump 6 are activated, the feed water from the feed heater 7 is sent to the feed / condensate purifier 10 from the header 13 and the inlet pipe 12 via the feed water purification pipe 17, where After being purified, it is returned from the outlet pipe 11 into the hot well of each of the main condensers 1, 2 and 3.

As described above, in the water supply / condensate purification device of the nuclear power plant according to the present invention, the water supply / condensate purifier using the non-filtering aid type hollow fiber membrane filter with a good cladding removal rate is used in combination, and By selectively operating each line of the hot well purification pipe 14, the condensate purification pipe 16 and the feed water purification pipe 17 by switching the valve and through the header, the feed water and condensate system can be purified evenly and efficiently. You can

The water supply / condensate purification device of the nuclear power plant of the present invention can also be used as a shared facility of a plurality of plants in order to increase the operating rate. The cleaning operation before the start of the plant is carried out for about 20 days at the end of the periodic inspection of the plant, and it is rare that a plurality of plants simultaneously perform the cleaning operation at the same power plant. Therefore, sharing the pre-start water supply / condensate purification device among a plurality of plants not only increases the operating rate but also contributes to a reduction in the initial cost.

The embodiment shown in FIG. 2 shows a case in which two plants, a unit A and a unit B, are used in common. The hot well purification pipe 14A, the condensate purification pipe 16A and the feed water purification pipe 17A of the Unit A are connected to the header 13 via valves V _2A , V _4A and V _5A respectively, and the hot well purification pipe 14B of the Unit B Water purification pipe 16B and water purification pipe 17B
_Is connected to the header via valves V _2B , V _4B and V _5B . This header 13 is connected via an inlet pipe 12 to a feed / condensate water purifier 10 using a hollow fiber membrane filter 9, and its outlet pipe 11 is connected to valves V _18A and V ₁₈ , respectively.
It is connected to the number A hot well 19A and the number B hot well 19B via return pipes 18A and 18B having _18B .

When implementing the water supply / condensate system purification of Unit A, open and close the valves V _2A , V _4A and V _5A of each line of the Unit A hot well purification pipe 14A, condensate purification pipe 16A and feedwater purification pipe 17A. Selective implementation by. At this time, the valves V _2B , V _4B and V _5B are closed in order to prevent the backflow to the unit B. At this time, the supply / condensation water from the Unit A is sent to the supply / condensate water purifier 10 via the header 13, and after being purified there, is returned from the outlet pipe 11 via the return pipe 18A to the Unit A hot well 19A. .

At this time, the return pipe 18B to the Unit B is isolated by closing the valve _V18B . Similarly, the supply / condensation water from the Unit B can selectively purify each line of the Unit B hot well purification pipe 14B, the condensate purification pipe 16B and the feed water purification pipe 17A by switching the respective valves.

The embodiment shown in FIG. 3 shows a case in which a backwash system is attached to a non-filtering aid type feed / condensate purifier 10 using the hollow fiber membrane filter 9 in the embodiment shown in FIG. . Condensed water from each line of the hot well purification pipe 14, the condensate purification pipe 16 and the feed water purification pipe 17 is a header.
The water is returned to the hot wells 1A and 1B of the main condenser 1 from the outlet pipe 11 after being sent to the water supply / condensate water purifier 10 via the inlet pipe 13 and the inlet pipe 12.

The backwash system consists of a compressed air source 20 and a water supply / condensate purifier 10 in the plant.
Are connected by backwash air pipes 21a and 21b, and further connected to the backwash water receiving tank 22 by a backwash water transfer pipe 23 and a backwash air vent pipe 24. The backwash water receiving tank 22 has a decant water transfer pipe 25.

The backwash operation is performed from the compressed air source 20 to the backwash air pipe 21a,
The in-house compressed air is sent into the water supply / condensate water purifier 10 through 21b to be pressurized and bubbled to remove the insoluble solids adhering to the hollow fiber membrane filter 9 in the water supply / condensate water purifier 10. Thereafter, the removed insoluble solid content is discharged from the backwash water pipe 23 into the backwash water receiving tank 22 by air or gravity. In the backwash water receiving tank 22, the clad and the water are separated by standing still, and the supernatant water is taken out from the decant water transfer pipe 25 as decant water and reprocessed, and the clad is stored in the tank 22.

Figure 4 shows a water supply / condensate purifier using a hollow fiber membrane filter.
1 shows the relationship between the number of days of supply / condensation system purification operation and the concentration of supplied / condensed water clad between 10 and the supply / condensate purifier 5 using an ion exchange resin. Characteristic l ₅ is an actual value when only the conventional water supply / condensate purifier 5 is used. Purification capacity is 1
Although it is 500 t / H, since the decontamination factor (DF) is as low as 1.34, it takes about 20 days to reduce the clad concentration to 200 ppb which is the cleaning operation termination standard.

Characteristics _l10A and _l10B are calculated values when the water supply / condensate purifier 10 is used. As a condition, the purification capacity was 700 m ³ / Hr, which was about half, and the DF was 100. Characteristic Characteristic l
The difference between _10A and _{110B is} the difference in the clad set value generated from the plant. The characteristic 1 _10A was set to a clad load amount about twice that of the characteristic 1 _10B . The characteristic l ₅ has the same load as the characteristic l _10B . As it can be seen from the characteristic l _10A and l _10B, by using a water-condensate purifier 10, 3-4
It is possible to lower the purification operation end standard to about 200 ppb in a day.

[Effect of the Invention] According to the present invention, by using a non-filtering aid type hollow fiber membrane filter in the water supply / condensate purifier attached to the water supply / condensation system of a nuclear power plant, The removal rate of the included clad is excellent, the generation of secondary waste is reduced, and it is possible to shorten the number of purification operation days by about 15 days, and the start-up of the plant is accelerated. It has the effect of contributing.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a water supply / condensate purification device for a nuclear power plant according to the present invention, and FIGS. 2 and 3 are system diagrams showing other different embodiments of the present invention. Fig. 4 is a characteristic diagram showing the relationship between the number of days of supply / condensation system purification operation and the concentration of the condensate / condensate in the water supply / condensate purification device. 1, 2, 3 ... Main condenser 1A-3B ... Hot well 4 ... Low pressure condensate pump 5 ... Condensate purifier using ion exchange resin 6 ... High pressure condensate pump 7 ... Water heater 9: Hollow fiber membrane filter 10: Water supply / condensate purifier using a hollow fiber membrane 13: Header 14: Hot well purification pipe 16: Condensate purification pipe 17: Water purification pipe V ₁ ~ V ₇ ... Valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Takahori 3-7-1, Nishishinbashi, Minato-ku, Tokyo Toshiba Plant Construction Co., Ltd. (56) References Nuclear Industry, Vol. 19, No. 3, No. 22 Page (1973) 1976 (19th) Annual Meeting of the Atomic Energy Society of Japan, Volume II, Volume 23 Page 23 (Atomic Energy Society of Japan, published March 10, 1981) Chemical Engineering, Volume 27 No. 5, pp. 20-25

Claims (1)

[Claims] 1. A hot well of a main condenser, a low pressure condensate pump, a valve (V ₁ ), a condensate purifier using an ion exchange resin, a high pressure condensate pump, a feed water heater, a feed water recirculation pipe and a valve ( V ₆ ) are sequentially connected, and are branched from between the feed water recirculation line returning to the hot well of the main condenser and the low-pressure condensate pump and the valve (V ₁ ).
₂ ), a header, an inlet pipe, a water supply / condensate purifier using a hollow fiber membrane filter, and an outlet pipe are sequentially connected, and the water supply / condensate purification line returns to the hot well of the main condenser, and the condensate purification vessels and is branched from between the high-pressure condensate pump valve (V _4), and condensate recirculation line valve (V ₇₎ and condensate recirculation pipe are successively connected back to the main condenser hot well, The valve (V ₄ ) and the valve (V
₇ )) a condensate purifying pipe that branches from between the header and the header, and a water supply that branches from between the feed water recirculation pipe and the valve (V ₆ ) and that connects to the header via the valve (V ₅ ). A water supply / condensate purification device for a nuclear power plant, comprising a purification pipe.