JPS61218994A - Purifier for water 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 [Field of Application of the Invention] The present invention relates to a BWR reactor water purification system, and particularly to a reactor water purification system that can effectively purify reactor water throughout the operation and shutdown of a granoto. Regarding the system.

[Background of the invention]

A conventional BWR reactor water purification system is shown in Figure 4. The functions of the reactor water purification system are to purify the reactor water during normal reactor operation and during reactor startup and shutdown to maintain the reactor water quality within standard values, and to maintain the reactor water quality within standard values. This function controls the reactor water level to a predetermined level by discharging the increase in reactor water due to thermal expansion and the increase in reactor water due to injection of cold water from the control rod drive hydraulic system.

In FIG. 4, the reactor water in the reactor pressure vessel 1 is taken out from the suction line of the reactor recirculation pump 2 and the bottom of the reactor pressure vessel 1 through take-out lines 3 and 4, respectively, and the lines merge and are stored. Through container isolation valve 5.6, 4 pump 5
The reactor water is pressurized at 1, cooled to a predetermined temperature (approximately 50°C) by a regenerative heat exchanger 52 and a non-regenerative heat exchanger 53, and purified by a super desalinator 54, and the purified reactor water is recycled. heat exchanger 5
2 and returned to the reactor through the water supply line 34.

Cooling in the non-regenerative heat exchanger 53 is performed by supplying cooling water cooled by the cooling source 15 through the inlet 16.

During normal reactor operation, reactor water is purified in the circulation cycle as described above, but the increased amount of reactor water discharged at the time of reactor startup passes through the filtration demineralizer 54 and then into the condenser. 10- to the condenser through line 56 to
This is done by discharging the waste through the waste receiving tank 57 of the waste treatment system.

By the way, in order to simplify the equipment of a BwR plant, there is a known example in which a turbine-based condensate desalination device is used to purify reactor water instead of the conventional single reactor water purification device as described above. It is disclosed in JP-A No. 54-36477. This connects the downstream side of the heat exchanger of the reactor residual heat removal system and the upstream side of the condensate desalination device of the turbine system, and cools the reactor water by passing reactor water through this during low reactor pressure and shutdown. The purpose is to purify the reactor water, remove crud, and reduce radioactivity. Normally, when a nuclear reactor is shut down, the reactor is cooled and depressurized by the reactor residual heat removal system, but in the above-mentioned known example, after the pressure inside the reactor has sufficiently decreased, the reactor water is transferred to the reactor residual heat removal system heat exchanger. After being cooled, the water is passed through a turbine-based condensate desalination device and then returned to the reactor through the water supply system. The reason why the reactor water is passed through the condensate desalination equipment after the reactor internal pressure has decreased sufficiently (that is, after the reactor water temperature has sufficiently decreased) is because the condensate demineralization equipment inlet line is at a normal temperature. The temperature is as low as about 40℃, and the pressure is about 6 to 8 kliF under normal reactor operating conditions.
/cttt2, it is necessary to sufficiently reduce the pressure and temperature.

Therefore, in the above known example, the reactor water cannot be purified when the reactor is at high pressure and high temperature.

Furthermore, while the reactor is operating, the reactor residual heat removal system is on standby as one of the emergency core cooling systems, so it cannot be used all the time. In this way, the range of use of the above-mentioned known example is limited to only when the reactor is at low pressure and when it is shut down. Furthermore, when the water supply system cannot be used during reactor shutdown or periodic plant inspections, for example, when inspecting or repairing the water supply system heaters and pumps, there is a problem in that the reactor water cannot be purified.

As mentioned above, providing the functionality of the reactor purification system to the turbine condensate desalination system will streamline plant equipment.
Although this is desirable in terms of simplification, the conventional proposals were not satisfactory in terms of usage conditions and usage range.

[Purpose of the invention]

The purpose of the present invention is to provide a reactor water purification system that maintains the original functions of the existing BWR equipment and performs a rational and effective reactor water purification function by sharing the existing equipment. be.

[Summary of the invention]

In order to achieve the above object, the reactor water purification according to the present invention effectively depressurizes the reactor water taken out from the reactor using a decompression means to purify the reactor water at high pressure and high temperature in the reactor during normal operation. The reactor water, which has been further cooled by cooling means, is passed through a filtration desalination device to be purified, heated, and returned to the reactor again. In this case, the purification function of the filtration and desalination device is All or part of the process is carried out by a condensate-based filtration and desalination equipment.

Condensate in the system to be purified is used as the cooling means, and a flash tank is used as the pressure reduction means.

Flash steam generated when high-pressure reactor water is depressurized is absorbed into the plant's internal steam line and recovered. Together with the use of condensate in the purification system, the release of thermal energy outside the ground is suppressed. There is.

In order to purify reactor water even when the water supply system is stopped during reactor shutdown or plant periodic inspections, the water supply system heaters, pumps, etc. are installed, and the purified reactor water is transferred to the reactor. It is configured so that it can be returned to

[Embodiments of the invention]

An embodiment of the present invention will be explained with reference to FIG. The reactor water purification system is the same as the conventional reactor water purification system up to the point where it passes through the reactor water extraction line 3゜4 from the reactor pressure vessel 1 and the containment vessel isolation valves 5 and 6, but after that, the extracted reactor water is
After passing through the flow control valve t, the pressure is once reduced to a predetermined pressure in a flash tank 8, and the reduced pressure reactor water is cooled to a predetermined temperature (approximately 50°C) in a heat exchanger 9, and then passed through a filter 10 to the reactor. It is configured such that the water is passed through the pump 11 or its bypass line 12, and is introduced into the upstream side of the condensate desalination device 28.

Here, to explain the configuration around the turbine, the steam generated from the reactor pressure vessel 1 is guided to the high-pressure turbine 22 through the main steam line 21, and the steam leaving the high-pressure turbine 21 is dehumidified by the moisture separator 23. It is removed and guided to a low pressure turbine 24 to rotate it. The steam leaving the low pressure turbine is cooled and condensed in the condenser 25, and the condensed water is
Pressurized by the low pressure condensate bonder 26, the condensate filtration device 27
The condensate is temporarily desalinated through the condensate desalination device 28, then the pressure is increased by the high-pressure condensate 29, heated by the low-pressure heater 30, 31, and the pressure is further increased by the water supply 4-de 32, It is heated by a high-pressure heater 33 and sent to the nuclear reactor through a water supply line 34. The high-pressure heater 33 is heated by extracted steam from the extraction line 42 of the high-pressure turbine, and the low-pressure heaters 30 and 31 are heated by extracted steam from the low-pressure turbine.

The heat exchanger 9 is cooled by introducing cooling water from the outlet line of the low pressure condensate bond 29 to the cooling water line 37,
After cooling the heat exchanger 9, the low pressure heater 3 is connected to the line 38.
It is designed to return to the exit side of 0. In addition to the above, cooling of the heat exchanger 9 is also performed by an independent cooling source 15.

Flood Island steam generated due to pressure reduction in the flash tank 8 passes through the 7 Lassie Island steam line 13 to the high pressure turbine 2.
A pressure control valve 13' is provided in the steam line 13 for flooding to control the pressure inside the seven lasier tank 8. In addition, the 7 Lassie steam line is connected to the condenser 25 via the pressure control valve 14.
I'm trying to be able to do it.

Further, from the outlet of the condensate desalination device 28, a water supply system Pino mother line 36 is provided, which is connected directly to the water supply line 34 by branching off the line. The condensate leaving the condensate desalination device 28 can be sent to the condenser 25 through a line 35 to the condenser 25, if necessary.

The overall configuration of the embodiment has been described above.Next, the operation mode of each mode will be explained during normal reactor operation, at reactor start-up, and after reactor shutdown.

During normal reactor operation, the reactor is in a high temperature and high pressure state, so the reactor water passed through the condensate desalination equipment 28 has a temperature of 40 to 6.
It is necessary to reduce the temperature and pressure to about 0°C and pressure to about 6 to 8 kg/cps2. Therefore, the reactor water taken out from the reactor 1 is first depressurized to a predetermined pressure in the flash tank 8.

When the pressure is reduced, a portion of the reactor water is flooded and steam is generated, so this flood island steam is released from above the 7 lash tank 8 to the main steam line at the outlet of the high pressure turbine 22. The main outlet of the high pressure turbine 22.

The pressure of the steam line is about 14 kg/tym2, and therefore the pressure inside the furanosis tank 8 is also about the same pressure.

The pressure of the reactor water is reduced in the black tank 8, and the temperature thereof is reduced accordingly, and the reactor water is cooled to a predetermined temperature (approximately 50° C.) in the heat exchanger 9. As the cooling water for the heat exchanger 9, condensate drawn from the outlet of the high-pressure condensate pump 29 is used. The outlet temperature of the reactor water heat exchanger 9 is monitored by a temperature detector 41, and the outlet temperature can be controlled by operating the cooling water side valve 40 based on the output signal and adjusting the amount of cooling water. ing.

The reactor water cooled to a predetermined temperature (approximately 50° C.) is filtered by the filter 10 and guided to the condensate desalination device 28 through the bypass line 12 of the I7 pipe 11. Here, since the reactor pressure is high during normal reactor operation, the reactor water does not need to be pressurized by the pump 11, and can be introduced into the condensate desalination device 28 by passing through the bypass line 12. The reactor water led to the condensate desalination device 28 is purified by the condensate desalination device 28 and returned to the reactor through the condensate system and the water supply system.

Although there may be concerns that the radiation dose will increase by introducing the reactor water to the condensate desalination equipment 28, the radiation dose is reduced because the reactor water is sufficiently cooled by the heat exchanger 9. Since the radiation is filtered by the filter 10, there is no particular problem regarding the radiation dose.

At the time of reactor startup, the reactor is under low pressure, so I Fugu 1
1 to lead the reactor water to the condensate desalination device 28. An increased amount of reactor water at the time of reactor startup is blown from the condensate desalination device 28 output line through the line 35 to the condenser 25.

Next, we will explain the operation after reactor shutdown. When the reactor water supply system is stopped due to regular inspections, etc., reactor water pressurized by 4-7'll is passed through the condensate desalination equipment 28 and then passed through the water supply system bypass line 36 to the reactor water supply system. Return to furnace. Also,
When the reactor is stopped, such as during high-temperature standby, but the water supply system is bypassed while the reactor is in a high-temperature state, the heat exchanger 9 cannot be cooled with condensate, so the independent The heat exchanger 9 is cooled by the cooling source 15. In this case as well, by operating the valve 39 in the return line to the cooling source 15 based on the signal from the temperature detector 41, the temperature of the reactor water at the outlet of the heat exchanger 9 can be controlled.

Other embodiments of the invention are shown in FIGS. 2 and 3.

The difference between FIG. 2 and FIG. 1 is that the flash steam from the flash tank 8 is configured to escape not to the outlet line of the high-pressure turbine 22 but to the bleed line of the same turbine 22. This embodiment is also possible since the steam lines are under the same pressure conditions.

The difference between FIG. 3 and FIG. 1 is that the filter 10 is not provided in the reactor water side outlet line of the heat exchanger 9, and the reactor water is introduced into the upstream side of the condensate filtration device 1i27. This is the point. Even with this configuration, the same function as the embodiment shown in FIG. 1 can be achieved.

[Effects of Examples]

According to the embodiment of the present invention described above, since the heat exchanger is cooled by condensate in the condensate system, the release of thermal energy to the outside of the plant is suppressed, resulting in improved thermal efficiency.

Since the conventional reactor water purification system as shown in FIG. 4 can be eliminated, the system can be simplified.

In addition, the pump 51 of the conventional reactor water purification system is installed at high pressure and high temperature, but in the example of the present invention, as shown in FIG. It is possible to reduce the radiation dose rate, improve the reliability of the pump, and improve the ease of maintenance and inspection.

〔Effect of the invention〕

According to the present invention, the function of the filtration desalination device of the conventional reactor water purification system of BwR can be replaced by the function of the condensate desalination device of the turbine system. In addition to the things that can be removed, the number of pumps 51 can be reduced by one during normal operation of the reactor and during high-temperature standby, and the number of regenerative heat exchangers 52 can be reduced by one.
can be deleted, simplifying and rationalizing the overall configuration.

Furthermore, by cooling the heat exchanger 9 with a condensate system, it is possible to rationalize the entire plant, such as reducing heat loss in the plant and improving the power generation output.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the present invention, and FIG. FIG. 3 shows a block diagram of another embodiment of the present invention. FIG. 4 shows a configuration diagram of a conventional nuclear reactor purification system. 8...Fludge gourd tank 9...Heat exchanger 11.
...Pump 27...Condensate filtration device 28.
...Condensate desalination equipment 30...Low pressure heater 36...
・Water supply system pie・arm line 37.38...cooling water line

Claims (1)

[Scope of Claims] 1. A nuclear reactor in which reactor water is taken out, depressurized by a decompression means, further cooled by a heat exchange means, purified by passing through a filtration desalination device, heated, and returned to the reactor again. 1. A nuclear reactor water purification device, characterized in that all or part of the purification function of the filtration and desalination device is performed by a condensate-based filtration and desalination device. 2. The reactor water purification system according to claim 1, wherein a part of the condensate that has passed through the desalination device of the condensate system is used as a heat exchange means for cooling the reactor water. 3. The reactor water purification system according to claim 1, characterized in that a flash tank is provided as means for reducing the pressure of high-pressure, high-temperature reactor water during normal operation of the reactor. 4. The atom according to claim 3, wherein the evaporation line from the flash tank is connected to a steam line such as a main steam line at the outlet of the high-pressure turbine or a bleed line of the high-pressure turbine, and a condenser. Reactor water purification equipment. 5. During reactor shutdown When the water supply line to the reactor is stopped, in order to return purified reactor water to the reactor, a line has been installed to bypass the feedwater heater and water supply system pumps, etc. A nuclear reactor water purification system according to any one of claims 1 to 4.