JPS60218096A - Boiling water reactor coolant purification system equipment - 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 coolant purification system equipment for a boiling water nuclear reactor, and more particularly to a so-called nuclear reactor in which a nuclear reactor is separated from a main steam turbine system. This invention relates to improvements to coolant purification system equipment for boiling water reactors that can supply emergency cooling water into the reactor in the event of an isolation accident. .

[Background of the invention]

Conventional (boiling water) nuclear reactor? ? First installation of Misaki wood purification system
As shown in the figure.

In FIG. 1, coolant taken out from a nuclear reactor 1 into a suction pipe 2 is cooled to a predetermined temperature (approximately 50 C) by a regenerative heat exchanger 3 and a non-regenerative heat exchanger 4. The coolant that has passed through the non-regenerative heat exchanger 4 is reduced to a predetermined pressure (approximately 7 kg/-.g) by a pressure control valve 5, and then guided to a filter 6 and a demineralizer 7 for purification. . The coolant purified by the filter 6 and the demineralizer 7 is pressurized by the circulation pump 8, and then returned to the reactor 1 through the discharge pipe 9 and the water supply pipe 10. A flow control valve 11 is installed in the middle of the discharge pipe 9, and the flow rate of this system is controlled to be constant by the flow control valve 11'. Further, two network vessel isolation valves 13 and 14 are installed in the middle of the suction pipe 2, located near the piping penetration portion of the reactor containment vessel 12. In the figure, 15 indicates an electric motor that drives the circulation pump 8.

In the above configuration, about 70
Kg/m-g of refrigerant is approximately 3 to 9/- in 7 parts of the demineralizer.
・The pressure is significantly reduced by the pressure control valve 5 so that a low operating pressure of about 100 g is obtained. Then, the pressure is increased again to about 70 kg/crA·gK by the circulation pump 8 and returned to the reactor 1.

In addition to the above-mentioned coolant purification system equipment, Figure 1 also shows:
Also shown is a so-called reactor isolation cooling system facility that supplies emergency cooling water to the reactor 1 in the event of a reactor isolation accident. The reactor-occasional cooling system includes a steam pipe 16 and a steam control valve 17.
, condensate storage tank 18, water pipe 19, water injection pump 20
In the event of a reactor isolation accident in which the reactor 1 is separated from the main steam turbine system, the circulation pump 8 is configured by the containment vessel isolation valve 13. It is forcibly tripped (OFF) by the closing signal of. In other words, if a reactor isolation accident occurs and the water level inside the reactor 1 drops abnormally, the water will flow out of the reactor 1 to the outside in order to prevent the water level from dropping any further. For all coolant systems, measures have been taken to automatically close the containment vessel isolation valves of each piping system, but in the coolant purification system, the containment vessel isolation valves indicated by numerals 13 and 14 in the drawing are replaced by this system. The containment vessel isolation valves 13 and 14 are automatically closed by an abnormally low water level signal in the reactor 1.

As described above, when the containment vessel isolation valves 13.14 are closed, the circulation pump 8 is cut off from the suction flow path from the reactor 1, so these containment vessel isolation valves 13.1
4, the pump 8 is also forced to trip.

In addition, from the standpoint of protecting the circulation pump 8 in case the suction pressure of the circulation pump 8 abnormally decreases,
The pump 8 is also forcibly tripped by the suction pressure drop signal of the circulation pump 8 itself.

When the circulation pump 8 is forcibly tripped as described above, the turbine 21 is driven by the reactor generated steam. When the turbine 22↓ is driven, the water injection pump 2
0 is started, and the water stored in the condensate storage tank 18 is supplied to the reactor 1 via the water injection pipe 19. In this way, the water level in the reactor 1 is maintained constant. drooping

Therefore, the water injection pump 20 of the above-mentioned make-up water piping system equipment
Since this is for injecting water stored in the condensate storage tank 18, which is a tank open to the atmosphere, into the reactor 1, the water injection pressure is equal to that of the coolant flowing in the discharge pipe 9 of the coolant purification system described above. As with the pressure, it is necessary to increase the pressure by 9/- gKf to approximately 70, and the total lift is approximately 800 m, which is extremely large, but the above-mentioned reactor isolation cooling system equipment is It is an emergency facility set up in anticipation of an isolation accident.
It is not used at all during normal reactor operation.

[Purpose of the invention]

The present invention was developed as a result of various studies in order to simplify the reactor piping system, and its purpose is to provide emergency cooling water within the reactor in the event of a reactor isolation accident. By combining the replenishment function with the cooling and material purification system equipment, it is possible to omit the installation of the reactor isolation cooling system equipment, which previously existed as an independent system, simplifying the plant construction process. The purpose of the present invention is to provide improved coolant purification system equipment for boiling water reactors, which can simultaneously reduce construction costs.

[Summary of the invention]

In order to achieve the above object, the present invention has a structure in which the coolant taken out from the nuclear reactor is cooled by a heat exchanger, purified by a filtration demineralizer, and then pressurized by a circulation pump and returned to the reactor again. Coolant purification system equipment for a boiling water reactor, characterized in that a make-up water piping system for replenishing cooling water into the reactor during reactor isolation is connected to the coolant suction side of the circulation pump. That is.

[Embodiments of the invention]

, Gogoko::::-;:::J:::::: This is a piping system explanatory diagram showing an example of furnace coolant purification system equipment, where the same reference numerals as in Figure 1 indicate the same parts, and 22 indicates An emergency cooling water injection pipe is shown that connects the coolant suction side of the circulation pump 8 and the condensate storage tank 18, and a check valve type water injection valve 23 is installed in the middle of the water injection pipe 22. The upstream side of the water injection valve 23, that is, the condensate storage tank 1B side, is constantly under pressure (approximately 2.5 kg) from the condensate storage tank 18 side.
/cr/I-g) has been added. On the other hand, the pressure on the downstream side of the water injection valve 23, that is, the suction pressure of the circulation pump 8, is controlled to a normal pressure of 3 Kf/-.g by the action of the pressure regulating valve 5. Therefore, due to the pressure difference between the upstream and downstream sides of the water injection valve 23, during normal reactor operation, the suction source of the circulation pump 8 always selects the reactor 1 side, and coolant is supplied from the condensate storage tank 18 side. There is no such thing as inhalation.

On the other hand, if a reactor isolation accident occurs and the containment vessel isolation valves 13 and 14 are automatically closed, unlike conventional methods, if the circulation pump 8 continues to operate without tripping, The suction pressure of the circulation pump 8 whose flow path with the reactor 1 was cut off is still the original pressure (approximately 3Kf).
/-・g) begins to gradually decrease. Then, the suction pressure of the circulation pump 8 is adjusted to the water injection valve 2 of the emergency cooling water injection pipe 22.
When the indentation pressure applied to 3 (approximately Z5Kf/-.g indentation pressure applied from the condensate storage tank 18 side) also decreases, the suction source of the circulation pump 8 is drawn from the condensate from the reactor 1 side. Automatically switching to the water storage tank 18 side, the circulation pump 8 can suck in cooling water from the condensate storage tank 18 through the water injection pipe 22 and replenish the reactor 1 with cooling water.

FIG. 3 shows another embodiment of the invention.

In the embodiment shown in FIG. 3, the driving source of the circulation pump 8 is
This is an example of the case where the turbine 24 is driven by reactor generated steam. According to this configuration, when the electrical system fails, the circulation pump 8 is driven using the reactor generated steam. This makes it possible to diversify pump drive sources.

FIG. 4 shows still another embodiment of the present invention.

In the embodiment shown in FIG. 4, a case is illustrated in which the driving source of the circulation pump is a diesel engine 25. According to this configuration, as in the embodiment shown in FIG. Even in this case, the circulation pump 8 can be driven using the diesel engine 25, and the pump driving source can also be diversified.

[Effects of the Invention] As detailed above, according to the present invention, the coolant purification system equipment can also have the function of replenishing emergency cooling water into the reactor in the event of a reactor isolation accident. The improved boiling system eliminates the need to install the reactor isolation cooling system, which previously existed as an independent system, and simultaneously simplifies the plant construction process and reduces construction costs. Coolant purification system equipment for water reactors can be obtained.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the piping system of the coolant purification system equipment and L reactor isolation cooling system equipment of a conventional (boiling water type) nuclear reactor, and Fig. 2 is a cooling system for boiling water reactors according to the present invention. Fig. 3 is an explanatory diagram of a piping system showing one embodiment of the material purification system equipment, Fig. 3 is an explanatory diagram of the piping system of the coolant purification system equipment showing another embodiment of the present invention, and Fig. 4 is an explanatory diagram of the piping system of the coolant purification system equipment showing another embodiment of the present invention. It is an explanatory diagram of a piping system of a coolant purification system equipment showing an example. DESCRIPTION OF SYMBOLS 1... Nuclear reactor, 2... Suction pipe, 3... Regenerative heat exchanger, 4... Non-regenerative heat exchanger, 5... Pressure control valve, 6
...Filter, 7...Demineralizer, 8...Circulation pump, 9...Discharge pipe, 10...Water supply pipe, 11...Flow rate control valve, 12...Atom Reactor containment vessel, 13 and 14・
...Containment vessel isolation valve, 15...Electric motor, 22...Emergency cooling water injection pipe, 23...Water injection valve, 24...Turbine, 25...Diesel engine. Agent Patent attorney Hiroo Nagasaki (and 1 other person) $l 2nd firm $J12] 4th mouth

Claims (1)

[Claims] 10. Coolant purification system equipment for boiling water reactors that has a structure in which the coolant taken out of the reactor is cooled with a heat exchanger, purified with a filtration demineralizer, then boosted with a circulation pump and returned to the reactor again. A coolant for a boiling water reactor, characterized in that a make-up water piping system for replenishing cooling water into the nuclear reactor during reactor isolation is connected to the coolant suction side of the circulation pump. Purification system equipment. 2. Coolant purification system equipment for a boiling water reactor, in which the driving source for the circulating water is a turbine driven by reactor steam. 3. Coolant purification system equipment for a boiling water nuclear reactor in which a diesel engine is used as a driving source for a circulation pump in the invention set forth in claim 1.