JPS60181697A - Refrigerator in nuclear power plant - 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 [Technical Field of the Invention] The present invention relates to a refrigeration system in a nuclear power plant that performs in-plant refrigeration by supplying refrigerant to a refrigeration tank in a nuclear power plant.

[Technical background of the invention and its problems] Generally, in nuclear power plants, in order to maintain a good working environment within the plant and to ensure proper operation of various equipment, coolers are installed at various locations within the plant to provide refrigeration. I am doing it.

FIG. 7 shows a conventional refrigeration system in a nuclear power plant of this type, which includes a plurality of (usually ≠ units installed, three in operation, and one in reserve) centrifugal chillers 1, The refrigerant is cooled by the refrigerant, and the refrigerant is delivered to the plurality of coolers through the refrigerant circulation path 3 by the circulation pump, thereby performing predetermined in-house freezing. Each centrifugal refrigerator l is driven by a power source jXr to cool the refrigerant. As this power source, electricity generated by a generator (not shown) of a nuclear power plant is used. Furthermore, a human robot bomb 6 is provided on the upstream side of each centrifugal refrigerator.

However, with this conventional device, when the centrifugal chiller l is rotated, large noise (e.g., 0 dB) and vibrations are generated, and some of the generated electricity is used as a drive source for the centrifugal chiller l. Therefore, it has the disadvantage that it is not efficient in terms of energy saving and operating costs.

Therefore, conventionally, as shown in Figure 2, a turbo chiller l
Instead, an absorption refrigerator 7 is provided to cool the refrigerant by effectively utilizing the heat source of steam generated in the nuclear reactor.

That is, the steam flowing out from the reactor pressure vessel g through the main steam pipe rotates the turbine 10 and the generator // connected thereto, thereby generating electricity. The steam flowing out of the turbine IO is cooled and condensed in the condenser /2 by the cold seawater in the seawater pipe /3,
The water is returned to the reactor pressure vessel r by the feed water pump/μ. Then, from the intermediate stage of the turbine 10 to the extraction pipe/
The steam extracted through S flows into the secondary steam generator /4, generates secondary steam, and returns as condensate to the condenser l through the reflux pipe /7. The steam generated by this secondary steam generator/A is clean and does not contain radioactive materials, and passes through the secondary steam supply pipe 7g with the gate valve/9 open to each absorption refrigerator 7.7. and cools the refrigerant sent by Herobo/Pro. Then, the secondary steam condenses in the absorption refrigerator 7 and passes through the reflux pipe 2.0 with the gate valve yu/6 open to the secondary steam generator/6.
It flows back to. In addition, the refrigerant cooled in the absorption refrigerator 7 is sent to each cooler through the refrigerant circulation path 3,
It is subjected to predetermined refrigeration within the facility, and then recycled to the absorption refrigerator 7 again.

In addition, as a backup facility for the secondary steam generator/A,
A house boiler U is connected in parallel to a secondary steam generator via a steam supply pipe and a return pipe. This house boiler n is used as a secondary steam generator/
/, is operated when it is inoperable to supply steam to the absorption chiller 7. At this time, the gate valve J1 installed in the steam feed pipe J and the return pipe J is fully opened, and the other gate valves /9,
:l/ is fully closed.

However, if the heating source to the secondary steam generator/6 were to stop due to some unknown reason during steady operation of this conventional device,
Steam is no longer supplied to the absorption refrigerator 7.7, and accordingly, the absorption refrigerator 7 is stopped, and sufficient refrigerant is no longer supplied to each cooler, resulting in a sharp reduction in refrigerating capacity. In such cases, conventionally the boiler was operated to supply steam to the absorption chiller 7, but the absorption chiller 7 restarted and the steam was supplied to the absorption chiller 7. It takes approximately 100 min to exert its cooling capacity. This absorption refrigerator 7
Because it takes a long time to restart the nuclear reactor, the temperature inside the dry well, where the refrigerant is supplied, would drop and the pressure would rise, potentially leading to an emergency shutdown of the reactor.

In addition, a large amount of energy is required to operate the Norus boiler during periodic inspections of the nuclear reactor, making it impossible to save energy.

[Purpose of the invention]

The present invention has been made in view of these points, and it is possible to constantly and stably supply refrigerant to the valleys of a nuclear power plant, provide appropriate cooling, and is highly reliable, with a mass An object of the present invention is to provide a refrigeration system in a nuclear power plant that can save energy by effectively utilizing thermal energy generated in a reactor.

[Summary of the invention]

The nuclear power plant refrigeration system of the present invention includes an absorption chiller that cools a refrigerant using reactor heat, and a centrifugal chiller that operates using electricity as a drive source to cool the refrigerant. The refrigerant circuits are provided in the middle of the refrigerant circulation path to the cooler.

[Embodiments of the invention]

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

FIG. 3 shows an embodiment of the nuclear power plant refrigeration system of the present invention.

In this embodiment, an absorption refrigerating machine 7 and a turbo refrigerating machine 27 are provided in parallel in the middle of the refrigerant circulation path 3 so that they can be freely switched and operated. Although shown in the figure, in reality, the absorption chiller 7 and the turbo chiller 27 are each provided with two stages, and the absorption chiller 7 is supplied with a heat source by KX as in Fig. 2. The turbo chiller 27 is supplied with electric power from the power source 3. The capacity of the absorption chiller 7 is set to be large enough to handle the steady load during plant operation. In addition, the capacity of the centrifugal chiller 27 is large enough to handle the load during periodic plant inspections, and the absorption chiller 27 can be used for short periods of time in summer.
It is said to be large enough to handle a load that cannot be borne by a computer.

Figure ≠ shows that the monthly average load rate of the refrigeration equipment during the annual plant operation of a 1 million KW class nuclear power plant, the steady heat load on the refrigeration equipment is approximately 41I%, and it depends on environmental changes such as outside temperature. The maximum value of the fluctuating load that changes accordingly is the number factor in the summer.

In order to bear this load, for example, a total of ≠ 7 refrigerators
, near capacity is 33 units each. Then, one of them is kept on standby as a spare.

Next, the refrigeration operation according to this embodiment will be explained.

Refrigeration operation during steady operation of the reactor In this case, the secondary steam generator 16 is operated, and the steam on the secondary side is sent to the two absorption refrigerators 7 using the heat source of the reactor, and the refrigerant circulation path is The refrigerant in 3 is cooled and sent to each cooler≠ to perform in-house refrigeration. Since these two absorption refrigerators 7 can handle a load of 6t1 as a whole, the steady load shown in the figure can be sufficiently covered.

When the fluctuating heat load increases and exceeds 66%, power is supplied from the power supply xg to one centrifugal chiller 27 to bear the load of 66% or more and continue proper refrigeration operation. do. The other centrifugal refrigerator, L7, is kept on standby as a backup.

In this way, in this embodiment, the steady heat load is handled by the absorption chiller 7, so it is possible to effectively utilize the reactor heat to perform in-station refrigeration. Since the centrifugal chiller 7 bears the variable heat load for one minute, there is almost no need to control the operating capacity of the entire system. In addition, the operating period of the centrifugal chiller 7 is short, and only one unit is operated, and the main operation is by the absorption chiller 7, which has few moving parts, so vibration and noise are kept to an extremely low level. It will be done.

In addition, if the heat source is no longer supplied to the secondary steam generator lt for some reason during steady operation, the
The centrifugal refrigerator near is started and operated to cool the refrigerant in the refrigerant circulation path 3, and the refrigerant is supplied to each cooler≠ to continue in-house refrigeration.

As described above, in this embodiment, when the absorption chiller 7 loses its refrigerant cooling capacity due to the stoppage of the supply heat source, the refrigerant can be cooled by the turbo chiller NIA, which has a short start-up time. Moreover, the refrigerating capacity of the two centrifugal chillers 7 is 66 cm, which can handle a sufficient heat load. Therefore, compared to conventional systems in which refrigerant is cooled only by absorption chillers, it is possible to perform better cooling within the station, and there is no need to accidentally stop the reactor when the absorption chiller is shut down. reliability becomes extremely high.

Refrigeration operation during periodic inspection of the nuclear reactor In this case, the nuclear reactor is in a stopped state and the absorption chiller 7 is inoperable. In this embodiment, two centrifugal refrigerators near are operated to perform refrigerant cooling and in-house refrigeration.

The refrigeration load rate during this periodic inspection is estimated to be approximately a%.
~SO Chidashi, since the two centrifugal refrigerators 27 have a cooling capacity of 66 degrees, sufficient freezing can be performed.

In addition, in this example, absorption refrigeration uses reactor heat to cool the refrigerant! 7"2=Since the turbo chiller 27, which uses electricity as a driving source, is used in parallel, it is possible to save energy compared to the conventional device equipped with only a centrifugal chiller, and as shown in Fig. The annual operating cost is Aj% of the conventional cost, and the running cost is also low.

Note that the absorption refrigerator 7 may be configured to cool the refrigerant using hot water as a heat source instead of secondary steam.

〔Effect of the invention〕

As described above, the nuclear power plant refrigeration system of the present invention can always stably cool various parts of the nuclear power plant without being affected by the operating status of the reactor, is highly reliable, and can save energy. It has the following effects:

[Brief explanation of drawings]

Fig. 7 and Fig. 2 are block diagrams showing a conventional refrigeration system in a nuclear power plant, respectively, Fig. 3 is a block diagram showing an embodiment of the refrigeration system in a nuclear power plant according to the present invention, and Fig. FIG. 5 is a diagram showing the load factor, and FIG. 5 is a diagram showing the ratio of annual operating costs between the device of the present invention and the conventional device. 3... Refrigerant circulation path, G... Cooler, 7... Absorption refrigerator, and... Reactor pressure vessel, 16... Secondary steam generator, : 17... Mebo refrigeration machine, 2g...power supply. Applicant's agent Inomata Kiyomi 1 Bacteria 4 Soa 5th item

Claims (1)

[Claims] / An absorption chiller that cools a refrigerant using reactor heat, and a centrifugal chiller that operates using electricity as a drive source to cool the refrigerant, are installed in a nuclear power plant. A refrigeration system in a nuclear power plant, characterized in that a refrigerant circuit is provided in the middle of a refrigerant circulation path to a cooler so that the operation can be switched between the two. 2. A patent characterized in that an absorption refrigerator is configured to cool a refrigerant using steam generated by being heated by the primary steam of a nuclear reactor in a secondary steam generator as a heat source. A refrigeration system in a nuclear power plant according to claim 1.