JPS6042693A - Method of cooling condenser for exhaust gas - 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 method for cooling an exhaust gas condenser of a boiling water nuclear reactor.

[Background of the invention]

A conventional exhaust gas condenser cooling method will be explained below with reference to FIG.

Inside the nuclear reactor 5, oxygen gas and hydrogen gas are generated by radiolysis of the reactor coolant. This oxygen gas/hydrogen gas and the activated gases such as oxygen and argon in the reactor coolant activated in the core fuel are collectively called exhaust gas, and the exhaust gas generated in the reactor 5 is After passing through the main steam pipe 9 together with the main steam to rotate the main turbine 6, it enters the main condenser 7.

Main steam is condensed in the main condenser 7 and returned to the reactor 5 as reactor condensate. On the other hand, the exhaust gas brought into the main condenser 7 is extracted by an air extractor 10, and the hydrogen gas concentration is reduced to 4%V01 with water vapor to keep it below the flammability limit of hydrogen gas.
．． The hydrogen gas and oxygen gas in the exhaust gas are diluted to below and heated in the exhaust gas preheater 11 to increase the efficiency of recombining oxygen and hydrogen, and the hydrogen gas and oxygen gas in the exhaust gas are recombined by a catalytic reaction in the recombiner 12 to become water vapor. The water vapor is condensed in the exhaust gas condenser 13 and separated from other rare gases.

The exhaust gas exiting the exhaust gas condenser 13 is sent to a waste treatment system 14 for treatment.

Two exhaust gas condensers 13 are installed in the turbine building 2,
Latent heat of water vapor in exhaust gas (40XIO-km/'h)
In order to remove and condense
/h of cooling water is required.

Conventionally, the exhaust gas condenser 13 was cooled by the reactor auxiliary equipment cooling system, so the reactor auxiliary equipment cooling system consists of each auxiliary equipment 8 in the reactor building 1, the exhaust gas condenser 13, and the turbine. In order to cool all of the radioactive auxiliary equipment 15 and other auxiliary equipment 16 other than the exhaust gas condenser in the building 2, the total amount of heat exchanged is 269 x 10'bl/h and the total amount of cooling water is 36 as shown in Table 1.
The reactor auxiliary equipment is designed to satisfy 8 x 10' days/h, and is equipped with piping to supply cooling water to each auxiliary equipment and piping to recover cooling water whose temperature has increased due to heat exchange. There was a drawback that the equipment cost and operating cost of the cooling system were high.

Furthermore, the reactor auxiliary cooling system heat exchanger 18 was cooled by seawater supplied by the reactor auxiliary cooling seawater system pump, and the heated seawater was discharged into the seawater through the discharge channel 24, so that the entire nuclear power plant This has the drawback of causing a deterioration in thermal efficiency and increasing the impact on the surrounding environment.

Furthermore, FIG. 2 shows the configuration of the control rod drive hydraulic system.

The control rod drive hydraulic system uses reactor condensate as a water source and is installed for the purpose of supplying high-pressure water, which is a driving source, to the control rods 25 that operate to adjust the reactor output and operate in the event of an emergency shutdown of the reactor, and includes a pump suction filter 27. , control rod driven water pump 28,
It consists of the control rod drive water filter 29 and piping and valves). In this control rod drive hydraulic system, since the water source is reactor condensate with a relatively low temperature, the piping inside the reactor-passage enclosure 4 is There is a possibility that dew condensation may form on the outside of the control rods 26. To prevent this, if the temperature of the reactor condensate is low, it is necessary to heat the control rod drive water before supplying it to the control rods 26.

Conventionally, a dedicated electric control rod drive water heater 30 has been installed to heat the control rod drive water, which has the drawback of increasing equipment costs and operating costs in the form of electricity for the heater 30.

[Purpose of the invention]

An object of the present invention is to reduce the capacity and amount of a reactor auxiliary cooling system without impairing the condensation function of the exhaust gas condenser, and to provide an exhaust gas that can effectively recover the heat of the cooling water given by the exhaust gas condenser. To provide a condenser cooling method.

[Summary of the invention]

The present invention utilizes a portion of nuclear reactor condensate as cooling water for an exhaust gas condenser, thereby achieving the above object.

[Embodiments of the invention and their effects]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows an embodiment of a so-called in-2-in condensate purification system in which a condensate purification facility is installed in the middle of the reactor condensate system. In the in-line condensate purification system, the reactor condensate coming out of the main condenser 7 is passed through a low-pressure condensate pump 31 and a condensate filtration device 32.
, the condensate desalination device 33 and the high pressure condensate pump 34, and are returned to the reactor. In this embodiment, a pipe 35 for supplying reactor condensate to the exhaust gas condenser 13 and its return pipe 36 are
Connected between the condensate desalination device 33 and the high pressure condensate pump 34,
The exhaust gas condenser 13 can be cooled by reactor condensate. In this case, it is desirable to install valves 37 and 39 at the entrance and exit of the exhaust gas condenser 13 for repair purposes, and to install an oriswiss 38 at the outlet of the exhaust gas condenser 13 for flow rate adjustment.

FIG. 4 shows an embodiment of a so-called side stream condensate purification system, which is equipped with dedicated condensate purification equipment separate from the reactor condensate system. In the IJ-M condensate purification method, reactor condensate taken out from the main condenser 7 by the condensate purification pump 40 is purified through the condensate filtration device 32 and the condensate desalination device 33. After that, it is returned to the main condenser 7. In this embodiment, a pipe 35 for supplying reactor condensate to the exhaust gas condenser 13 and its return pipe 36 are connected between the condensate desalination device 33 and the main condenser 70. This allows cooling to be performed using reactor condensate. In this case as well, similarly to the in-line condensate purification method, valves 37 and 39 are installed at the entrance and exit of the exhaust gas condenser 13 for repair purposes, and an oriice 38 is installed at the outlet of the exhaust gas condenser 13 for flow rate adjustment. This is desirable.

According to the above two actual flow sides, there is no need to cool the exhaust gas condenser 13 with the reactor auxiliary equipment cooling system, and the reactor auxiliary equipment cooling system is used for each auxiliary equipment 8 in the reactor building 1 and the turbine building 2. It is only necessary to cool the radioactive auxiliary equipment 15 and other auxiliary equipment 16 other than the exhaust gas condenser inside.

Therefore, as shown in Table 2, the system capacity of the reactor auxiliary cooling system can be reduced by about 15% in total heat exchange and by 11% in total amount of cooling water compared to the conventional technology.

Furthermore, in the prior art shown in FIG. 1, the exhaust gas condenser 13
The cooling water supply piping 22 from the reactor auxiliary equipment cooling system to the reactor auxiliary equipment cooling system and its return piping 23 can be deleted, and the piping 2 that supplies cooling water from the reactor auxiliary equipment cooling system to the auxiliary equipment in the turbine building 2 can be removed.
Since the flow rate in the pipes 0 and 2 return pipes has been reduced to about 1/4, the diameters of the pipes 20 and 21 can be reduced to 1/2, reducing the number of pipes and valves. I can do it.

Furthermore, since the amount of heat exchanged by the reactor auxiliary cooling system heat exchanger 18 is reduced, the required amount of cooling water is also reduced, so it is possible to reduce the system flow rate of the reactor auxiliary cooling seawater system by approximately 11%. be.

On the other hand, the latent heat of the water vapor in the exhaust gas taken away by the exhaust gas condenser 13 was conventionally released to seawater via the reactor auxiliary cooling system and the reactor auxiliary cooling seawater system, but in this implementation According to the example, since it can be effectively recovered to the reactor condensate,
The thermal efficiency of the entire nuclear power plant has been reduced from the conventional 33.4% to 3&
It is possible to increase it to 5%.

The problem with the embodiments shown in FIGS. 3 and 4 is that the temperature of reactor condensate is approximately 3C in the in-2-in condensate purification power system relative to the cooling water supply temperature of the reactor auxiliary cooling system. % in the side stream condensate purification system, which is about 20% higher, which has the disadvantage that the heat transfer area of the exhaust gas condenser 13 is slightly larger. The increase in heat transfer area is approximately 6% for the in-line condensate purification method and approximately 4% for the sidestream condensate purification method. It is thought that the effect of reducing valves and reactor auxiliary equipment cooling seawater system pump 19, piping, and valves (equipment cost reduction effect) will be significantly greater.

In the embodiment described above, the connection position of the reactor condensate supply pipe 35 to the exhaust gas condenser 13 and its return pipe i6 is between the condensate desalination device 33 and the high-pressure condensate pump 34 in the in-line condensate purification system. In the side stream condensate purification method, it was connected between the condensate desalination device 33 and the main condenser 7, but it could be connected to another location where the reactor condensate temperature conditions are the same and the pressure during operation is relatively low. Te (9) is also good. That is, in the in-line condensate purification method, there is a connection between the condensate filtration device 32 and the condensate desalination device 33 or between the low-pressure condensate pump 31 and the condensate filtration device 32, and in the Cytos Lee A condensate purification method, the condensate filtration device 32 and the condensate desalination device 33 or between the condensate purification pump 40 and the condensate filtration device 32. When connecting to the upstream side of the condensate desalination device 33, if the inlet temperature of the condensate desalination device 33 is too high, the precoat resin loaded in the condensate desalination device 33 for ion exchange will deteriorate, and the demineralization device 33 will deteriorate. Although there is a concern that the salt performance will deteriorate, the temperature rise of reactor condensate due to heat exchange in the exhaust gas condenser 13 is approximately 0.6C in the in-line condensate purification method and 1.5C in the sidestream condensate purification method. The temperature rise is about IC, and is not such a temperature rise as to cause a decrease in the performance of the condensate desalination device 33.

FIG. 5 shows another embodiment of the present invention, in which the exhaust gas condenser 13
The reactor condensate supply pipe 35 to the control rod drive hydraulic system is partially used in common with the conventionally installed reactor condensate supply pipe 46 to the control rod drive hydraulic system. According to this embodiment, the number of (10) weld lines on the downstream piping of the condensate desalination device 33 can be reduced.

FIG. 6 shows an embodiment in which part of the reactor condensate that has passed through the exhaust gas condenser 13 is supplied to the control rod drive hydraulic system. According to this embodiment, the control rod driven water heater 3 in the prior art
Control rod driving water can be heated using the reactor condensate whose temperature has increased without using zero, and dew condensation on the outside of the piping inside the reactor-fireway enclosure can be prevented. in this case,
In order to maintain the control rod drive water above the dew point temperature in the reactor-defective containment vessel 4, a thermometer 43 and a reactor condensate supply pipe from the exhaust gas condenser 13 are installed in the middle of the piping of the control rod drive hydraulic system. A temperature control valve is installed on 41.

During normal operation, the reactor condensate supply flow rate from the outlet of the exhaust gas condenser 13 to the control rod drive hydraulic system to prevent the temperature of the control rod drive water from falling below the dew point temperature in the reactor-defective containment vessel 4 is as follows:
In-line condensate purification method: 7% of total control rod drive water flow rate
In the side stream condensate purification method, it is about 10% of the total control rod drive water flow rate.

FIG. 7 shows another embodiment of the present invention, in which a radioactive auxiliary machine 15 other than the exhaust gas condenser inside the turbine (11) building can also be cooled by reactor condensate. According to this embodiment, the system capacity of the reactor auxiliary cooling system is further increased from the previous embodiment to approximately 7% in terms of total heat exchange (approximately 21% from the conventional technology) and approximately 4% in total cooling water amount (compared to the conventional technology). 15%), and the piping 20 that supplies cooling water from the reactor auxiliary cooling system to the turbine building 2 and its return piping 21 in FIG. 1 can be deleted.

Furthermore, the thermal efficiency of the entire nuclear power plant is further reduced to 0 from the above example.
．． It can be increased by about 0.01%.

The effects of the above-described embodiments of the present invention are summarized as follows.

(1) The system capacity of the reactor auxiliary equipment cooling system can be significantly reduced. The amount of reduction is about 15 to 21% in the total amount of heat exchanged and about 11 to 15% in the total amount of cooling water compared to the conventional technology.

(2) The diameter of the cooling water supply piping and return piping of the reactor auxiliary equipment cooling system can be reduced or partially deleted.

(12) (3) The system flow rate of the reactor auxiliary equipment cooling seawater system can be reduced. The amount of reduction is about 11 to 15% compared to the conventional technology.

(4) The thermal efficiency of the entire nuclear power plant can be increased by about 0.1%.

(5) It is possible to prevent dew condensation in the piping within the reactor-subcontainment vessel even without the control rods and the control rod drive water heaters of the drive hydraulic system.

[Brief explanation of the drawing]

Figure 1 is an overall schematic diagram of a nuclear power plant that uses the conventional technology for exhaust gas condenser cooling, Figure 2 is a system diagram of the control rod drive hydraulic system using the conventional technology, and Figures 3 to 7 are the main illustrations. FIG. 8 and FIG. 9 are diagrams showing a breakdown of the system capacity of the reactor auxiliary cooling system for the conventional example and the example, respectively. 1... Reactor building, 2... Turbine building, 3...
Seawater heat exchanger building, 4... Reactor-fireway containment vessel, 5.
... Nuclear reactor, 6... Main turbine, 7... Main condenser,
8... Reactor building indoor sleeve machine, 9... Main steam pipe, 10...
...Air extractor, 11...Exhaust gas preheater, 12...
Recombiner, 13... Exhaust (13) Gas condenser, 14... Waste treatment equipment, 15... Radioactive auxiliary equipment in the turbine building (other than exhaust gas condenser), 16.
... Other auxiliary equipment, 17... Reactor auxiliary equipment cooling system pump, 18... Reactor auxiliary equipment cooling system heat exchanger, 19... Reactor auxiliary equipment cooling seawater system pump, 20-23. ...Reactor auxiliary equipment cooling system piping, 24...Discharge path, 25...Control rod,
26... Control rod drive hydraulic system reactor-next containment vessel internal piping, 27... Pump suction filter, 28... Control rod drive water pump, 29... Control rod drive water filter,
30... Control rod driven water heater, 31... Low pressure condensate pump, 32... Condensate filtration device, 33... Condensate desalination device, 34... High pressure condensate pump, 35... ...Exhaust gas condenser reactor condensate supply piping, 36...Exhaust gas condenser reactor condensate return piping, 37...Exhaust gas condenser inlet repair valve, 3
8-orifice, 39...exhaust gas condenser outlet repair valve,
40... Condensate purification pump, 41... Exhaust gas condenser outlet reactor condensate supply piping, 42... Temperature control valve, 43...
...Temperature detector, 44...Radioactive auxiliary equipment reactor condensate supply piping in the turbine building, 45...Radioactive auxiliary equipment reactor condensate return piping in the turbine building, 46...Control rod drive water pressure (
14) System reactor condensate supply piping. Agent Patent attorney Akio Takahashi (15)

Claims (1)

[Claims] 1. An exhaust gas condenser is provided to condense water vapor in the exhaust gas generated in the boiling water reactor, and cooling water is supplied to the exhaust gas condenser to exchange heat with the exhaust gas. An exhaust gas condenser cooling method characterized in that a part of the reactor condensate condensed in the main condenser is used as cooling water for the exhaust gas condenser. 2. The exhaust gas condenser cooling method according to claim 1, wherein the reactor condensate is supplied from a reactor condensate system. 3. The exhaust gas condenser cooling method according to claim 1, wherein the reactor condensate is supplied from a reactor condensate purification system. 4. The exhaust gas condenser cooling method according to claim 1, characterized in that the reactor condensate is supplied from piping of a control rod drive hydraulic system. 5. Part of the reactor condensate that has passed through the exhaust gas condenser and whose temperature has increased is supplied to the control rod drive hydraulic system. 4. Exhaust gas condenser cooling method.