JPH10232293A - Boiling water nuclear power plant - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To simplify the equipment of the entire plant including the radioactive waste treatment equipment by simplifying the condensate purification system equipment, and further reduce the amount of radioactive waste generated. SOLUTION: Steam generated in a nuclear reactor performs work in a turbine 2 and is condensed in a condenser 3 of a condensate purification system, and is condensed in a low pressure condensate pump 4, a condensate filter 5, a high pressure condensate pump. It is led to the water supply system via 6. That is, the condensate desalter 14 is omitted. Insoluble impurities such as iron clad in the condensate are removed by the condensate filter 5. The reactor coolant purification system 12 is led from the reactor recirculation system 13, and is led to the reactor via the regenerative heat exchanger 9, the non-regenerative heat exchanger 10, the filter desalter 11, and the regenerative heat exchanger 9. . Soluble impurities (ion components) and insoluble impurities in the reactor water are removed in the filter and desalter 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boiling water nuclear power plant, and more particularly to reduction of construction and maintenance costs due to downsizing of a condensate purification system and backwashing of a condensate purification system. The present invention relates to a technology capable of reducing the amount of waste generated at the time.

[0002]

2. Description of the Related Art In a conventional boiling water nuclear power plant, a condensate purifying apparatus is provided with a condensate desalinator 14 (CD) alone or a condensate filter 5 (CF) and a condensate filter 5 (CF). Either both of the condensate desalter 14 (CD) are installed, or either of them is adopted. In the latter, as shown in FIG. 8, the low-pressure condensate pump 4 and the condensate filter 5 , A condensate desalinator 14 and a high-pressure condensate pump 6 in that order. The condensate filter 5 mainly removes insoluble impurities in the condensate by using a precoat type filtration membrane in which a powder resin is precoated on the element surface in the condensate filter.
On the other hand, the condensate desalinator 14 mainly removes soluble impurities (ion components) in the condensate by the granular ion exchange resin filled in the condensate demineralization tower. By the above-mentioned condensing filter 5 and condensing deionizer 14, by carrying out function sharing and continuous filtration and desalination, the amount of clad components such as iron introduced into the nuclear reactor and the soluble impurities are reduced, The quality of water supply is being improved. The condensed water that has passed through the condensate purification device returns to the reactor 1 via the feedwater heater 7, the feedwater pump 8, and the feedwater heater 7. The condensate filter 5 has a backwash water tank 5a as ancillary equipment, and the condensate desalinator 14 has a backwash water tank 14a, a chemical regenerating liquid tank 14b, a chemical waste liquid tank 14c, and a waste storage facility 14d. Provided.

[0003] Further, a reactor coolant purification system 12 (CUW system)
Also in the above, a filter desalinator 11 or a desalinator is installed, and the quality of the reactor water is improved by removing impurity ions and the like in the reactor water. The reactor coolant purification system 12 is diverted from the reactor recirculation system 13, first passes through the regenerative heat exchanger 9 and the non-regenerative heat exchanger 10, and is then purified by the filter and desalinator 11. 9 again to return to the reactor 1.

According to Japanese Patent Application Laid-Open No. 8-152496,
It is described that the clad is reduced by improving the material of the turbine system piping, and the condensate purification system is simplified by installing only the condensate desalinator 14. In this case, the condensate desalinator 14
Since the performance of removing the clad by the granular resin is not high, it is difficult to reduce the iron clad concentration of the feed water to the target of 1 ppb or less. Further, as shown in FIG. 8, a chemical regeneration facility is required, and a waste liquid treatment facility is required in the treatment of radioactive waste.

On the other hand, if only the condensate filter 5 is installed, the equipment can be simplified, and since the filter is installed, 90% or more of the removal performance of the clad can be secured.

According to the results of the boiling water nuclear power plant, the water quality of condensate during normal operation has a conductivity of 0.05.
It is known that high purity of about 5 to 0.06 μS / cm is maintained. Therefore, soluble impurities (ionic components)
Even if not removed, the conductivity of the reactor water can be suppressed to a predetermined value or less.

[0007]

On the other hand, the condensate double type purification system in which both the condensate deionizer 14 and the condensate filter 5 are installed as a condensate purification system has a large-scale facility. It is desired to simplify these. Further, in operating the condensate desalinator 14 and the condensate filter 5 constituting the condensate purification system, it is necessary to monitor various items. In other words, at the outlet of the condensate desalinator 14, when the values such as the conductivity and the clad concentration deviate from the target control values, measures such as regeneration of the condensate desalinator 14 or backwashing / washing are performed. There is a need to.

[0008] While the condensate filter 5 can be regenerated only by backwashing, the condensate desalinator 14 is regenerated, or radioactive waste is generated by backwashing and washing. Therefore, the condensate desalter 14 has a backwash water tank 14a,
b, a chemical waste liquid tank 14c, a waste storage facility 14d, and the like are provided as auxiliary facilities.

Therefore, from the viewpoint of reducing the amount of radioactive waste generated, it is desirable not to install the condensate desalinator 14, which is the main source. In addition, by installing the condensate filter 5 alone without installing the condensate desalinator 14, the above-mentioned incidental equipment becomes unnecessary, and the equipment can be made compact.

[0010] An object of the present invention is to simplify the equipment of the condensate purification system, thereby simplifying the equipment of the entire plant including the equipment for treating radioactive waste, and further reducing the amount of generated radioactive waste. is there.

[0011]

According to a first aspect of the present invention, there is provided a boiling water nuclear power plant comprising a condensate purification system and a reactor coolant purification system.
It is a boiling water nuclear power plant in which a condensate filter capable of removing insoluble impurities is installed alone in the condensate purification system.

According to a second aspect of the present invention, in order to achieve the above object, the condensate filter according to the first aspect is characterized in that the condensate filter is either a non-aid filter or a powdered resin precoat type filter desalinator. It is characterized by being a nuclear power plant.

According to a third aspect of the present invention, in order to achieve the above object, when the conductivity or the chloride ion concentration in the condensate increases to a predetermined value or more,
It is a boiling water nuclear power plant equipped with a system for isolating a condenser and urgently stopping the operation of a nuclear reactor.

According to a fourth aspect of the present invention, in order to achieve the above object, the operation of the nuclear reactor is urgently stopped when the conductivity or the chloride ion concentration in the condensate rises to a predetermined value or more. In doing so, the reactor is characterized by being a boiling water nuclear power plant equipped with a system having a function of removing impurities in reactor water by performing a reactor coolant purification system capacity increase operation.

[0015]

The operation of the above means is that the condensate dewatering device is eliminated from the condensate purification system and the condensate filter is replaced with a simple structure. The amount of radioactive waste generated during washing is reduced.

[0016]

FIG. 1 is a block diagram of a boiling water nuclear power plant according to a first embodiment of the present invention. Reactor 1
After the steam generated in the inside performs work in the turbine 2, it is condensed in the condenser 3, and the low-pressure condensate pump 4, the condensate filter 5, the high-pressure condensate pump 6, the feedwater heater 7, the feedwater pump 8, It returns to the reactor 1 via the feed water heater 7. Insoluble impurities such as iron clad in the condensate are removed by the condensate filter 5.

The reactor coolant purification system 12 is led from the reactor recirculation system 13 and is provided with the regenerative heat exchanger 9 and the non-regenerative heat exchanger 1.
0, through the filter desalinator 11 and the regenerative heat exchanger 9, to the reactor 1. Soluble impurities (ion components) and insoluble impurities in the reactor water are removed in the filter and desalter 11.

FIG. 2 shows a calculation result of a temporal change in the impurity concentration of the reactor water due to a difference in CUW capacity. Here, 110
At a 0 MWe BWR plant, the reactor possesses 400 tons of water, a CUW capacity of 2%, and a CUW flow rate of 120 tons / hr.
It was assumed that the feedwater flow rate was zero. As shown in FIG. 2, it can be seen that as the CUW capacity increases, the purification is performed more quickly in a shorter time. For example, to purify the reactor water impurity concentration to half the concentration, it takes 2 hours and 40 minutes for a CUW capacity of 2%, and 1 hour and 20 minutes for a CUW capacity of 4%.
It takes 40 minutes for a W capacity of 8%.

As a result, even if a leak occurs in the condenser tube, it is possible to prevent the water quality from deteriorating by operating with an increased CUW capacity.

Therefore, for example, during normal operation, the CUW is operated at a CUW capacity of 2%, and when the condensed water conductivity increases due to seawater leak or the like, the CUW is operated with an increased capacity to prevent deterioration of the reactor water quality. It is possible.

FIG. 3 shows the relationship between the condensed water conductivity and the reactor water conductivity using the capacity of the reactor coolant purification system 12 (CUW system) as a parameter. Here, the impurity ion component (conductivity-contributing component) brought in from the condensate during the operation of the plant is mixed in the reactor water and accumulated, while the reactor coolant purification system 12
The stable conductivity level was calculated and evaluated assuming that 90% of the soluble impurities flowing into the sample were removed. As shown in FIG.
The soluble impurities brought in from the condensate are concentrated in the reactor water, but depending on the conductivity of the condensate, the reactor water can be controlled to a predetermined conductivity or less by increasing the CUW capacity. It indicates that there is.

FIG. 4 shows a second embodiment of the present invention. There are two types of condensate filters 5: non-aid filter or powder resin precoat type filter desalter.

As the non-aid filter, there is a filter using a hollow fiber membrane shown in FIG. 4, for example. The hollow fiber membrane is made of a polymer, and the surface thereof is 0.1 to
It has a porous membrane structure composed of uniform pores on the order of 0.25 μm. Accordingly, this causes most of the insoluble impurities in the condensate to accumulate on the hollow fiber membrane, and the removed filtered water is guided to the water supply system. Since no pre-coat material such as powdered resin is used, the equipment is simplified and the amount of waste generated is small.

If the soluble impurities in the reactor water cannot be removed to the target value only by the filtration and desalination unit 11 of the reactor coolant purification system 12, the condensate purification system uses the powder as a condensate filter. Equipped with a resin precoat-type filtration desalter. In the powder resin pre-coating type filter desalter, the element surface is composed of a powder resin layer of several mm order. Since the powdered resin has an electric charge, filtration is performed in the powdered resin by both adsorption and filtration.

Alternatively, as a non-aid type filter, a filter cloth folded in a pleated shape and wound into a cylindrical shape is used as an element,
It is also possible to use a filtration device (pleated type non-aid material filter) for filtering raw water with a pleated filter cloth.

FIG. 5 shows a third embodiment. In this system, the chlorine ion (C) contained in the seawater is used because the seawater used for the cooling water of the condenser 3 leaks in the condensing system.
When the conductivity is significantly increased due to soluble impurities such as l ⁻ ), the reactor is shut down urgently.

For example, an impurity ion in the condensate is identified and its concentration is detected by a chemical analyzer 14 such as an ion chromatography. The detected value is converted by the signal converter 15 and the signal is sent to the water supply system. The signal converter 15 stores an allowable value of density as a set value in advance. If the concentration of the soluble impurities in the condensate exceeds the set value, the signal is transmitted to the main control room, so that the condenser 3 can be isolated and the reactor can be safely shut down at the same time.

In the unlikely event that seawater leaks in large quantities during condensing due to, for example, breakage of the condenser 3 tubes, the plant is stopped as described above, so this does not pose a major problem.

FIG. 6 shows an example of a configuration diagram for isolating the condenser 3. In the condenser 3, seawater flows as cooling water in the condenser 3 tube by a circulation pump, and steam is condensed into water. If the condenser tube is damaged and the reactor water ion concentration (chlorine ion, etc.), reactor water conductivity, etc. rises sharply due to seawater leak, close the seawater supply valve and close the seawater supply valve. Further inflow is prevented and the condenser 3 is isolated.

As a fourth embodiment, when the conductivity or the impurity concentration of the condensed water becomes equal to or higher than a predetermined value, the operation of increasing the capacity of the reactor coolant purifying system 12 is performed to execute the operation in the reactor 1 water. This prevents the impurity concentration from increasing. This operation can be used as a provisional measure for water purification at the stage of making an emergency shutdown of the plant, or can be used for both reactor water purification operations after an emergency shutdown.

FIG. 7 shows a procedure leading to the above-mentioned emergency shutdown of the reactor 1 or operation for increasing the capacity of the reactor coolant purifying system 12.

The condenser outlet conductivity increases due to seawater leak or the like (S1). It is determined whether or not the condenser outlet conductivity has risen above a predetermined value (S2). If it is higher than the predetermined value, the condenser is isolated (S3), and the reactor is shut down emergency (S3).
4). If the value is equal to or less than the predetermined value, a CUW (reactor coolant purification system) capacity increasing operation is performed (S5). It is determined whether the reactor water conductivity has risen above a predetermined value (S6). If it is higher than the predetermined value, the condenser is isolated (S3), and the reactor is shut down emergency (S4). If it is equal to or less than the predetermined value, the operation is continued (S7).

As described above, according to the present invention, the condensate purification system can be greatly simplified as compared with a conventional boiling water nuclear power plant.

[0034]

The first effect of the present invention is that the purification device of the condensate purification system is constituted only by the condensate filter, so that the equipment can be simplified and the construction cost and maintenance cost can be reduced.

The second effect is that the radioactive waste generated at the time of backwashing / regeneration of the condensate purification system can be reduced by not installing a condensate demineralizer.

[Brief description of the drawings]

FIG. 1 is a process flow chart showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a reactor water purification time and a reactor water impurity concentration ratio using a reactor coolant purification system capacity as a parameter.

FIG. 3 is a diagram showing a relationship between condensate conductivity and reactor water conductivity using a reactor coolant purification system capacity as a parameter.

FIG. 4 is a non-aid filter using a hollow fiber membrane.

FIG. 5 is a process flow chart showing a third embodiment of the present invention.

FIG. 6 is a configuration diagram of a method of isolating a condenser.

FIG. 7 is an emergency shutdown procedure.

FIG. 8 is a conventional process flow diagram.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reactor 2 ... Turbine 3 ... Condenser 4 ... Low-pressure condensate pump 5 ... Condensate filter 6 ... High-pressure condensate pump 7 ... Feedwater heater 8 ... Feedwater pump 9 ... Regeneration heat exchanger 10 ... Non-regenerative heat Exchanger 11: Filtration desalter 12: Reactor coolant purification system 13: Reactor recirculation system 14: Condensate desalter 15: Chemical analyzer 16: Signal converter 5a: Backwash water tank 14a: Backwash Water tank 14b… Chemical regenerated liquid tank 14c… Chemical waste liquid tank 14d… Waste storage equipment

Claims (4)

[Claims] In a boiling water nuclear power plant having a condensate purification system and a reactor coolant purification system, a condensate filter capable of removing insoluble impurities is independently installed as a condensate purification system. A boiling water nuclear power plant, characterized in that: 2. The boiling water nuclear power plant according to claim 1, wherein the condensate filter is one of a non-aid filter and a powdered resin precoat type filter and desalinator. 3. A system for isolating the condenser and urgently stopping the operation of the reactor when the conductivity or the chloride ion concentration in the condensate rises above a predetermined value. The boiling water nuclear power plant according to claim 1 or 2. 4. When the conductivity or chlorine ion concentration in the condensate rises to a predetermined value or more, when the operation of the nuclear reactor is emergency stopped, by performing a reactor coolant purification system capacity increasing operation, The boiling water nuclear power plant according to claim 3, further comprising a system having a function of removing impurities in the reactor water.