JPH043520B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a drain level detector for a steam/water separator for nuclear power generation, and particularly to a drain level detector that has a simple structure and is suitable for absorbing differences in thermal expansion. Regarding the cradle.

[Conventional technology]

The circulating steam used in boiling water nuclear power generation (BWR) contains radioactivity, but accidents that result in leakage of this steam and exposure to radiation must be prevented at all costs to ensure a safe power plant.

In addition, nuclear power plants require huge investments,
In order to increase its economic effectiveness, the operating rate must be improved. Improving equipment reliability is most important for this purpose.

In recent years, nuclear power plants have been focusing on the safety of the equipment,
As a measure to improve reliability, multiplexing of measuring instruments (installing multiple identical instruments at one measuring point) is being attempted. The drain level detection of a serious water separator is no exception; for example, three drain level detectors are installed for one drain level measurement point.
The system is designed to stop power generation if two of the three detectors are activated.

Figure 1 systematically shows the mechanism of nuclear power generation. Steam 2 produced in the reactor 1 enters the high-pressure turbine 3 to do work, passes through the steam-water separator 4, enters the low-pressure turbine 5 to do work, and then becomes the drain 7 in the condenser 6, and is sent to the feed water heater. 8 and enters the nuclear reactor 1 to be reused.

The steam-water separator 4 separates multiple moisture contained in the steam 2a output from the high-pressure turbine 3, and supplies steam 2b close to dry steam to the low-pressure turbine 5, improving efficiency and reducing turbine erosion. The aim is to prevent the occurrence of The drain separated by the steam-water separator 4 is collected in a drain tank 9 and introduced into the feed water heater 8 as a drain 10. The level detector 11 is installed near the connection between the lower body of the steam separator 4 and the drain tank 9.

FIG. 2 is a three-dimensional view of the settings of the main equipment shown in FIG.

The high-pressure turbine 3 and the low-pressure turbine 5 are set on a turbine pedestal 14, and the steam-water separator 4, which is integrated with the drain tank 9, is set on the side thereof. This steam/water separator 4 has cross-around pipes 12 and 13.
It is connected to the high pressure turbine 3 and the low pressure casing 5 via.

Usually 200 in the cross-around pipes 12 and 13.
Thermal expansion occurs as steam around ℃ flows. Therefore, it is necessary to absorb this thermal expansion, but since the steam/water separator 4 and the drain tank 9 weigh more than 100 dollars, it is extremely difficult to install it on the floor and absorb the thermal expansion.

FIG. 3 shows an installation diagram of the steam/water separator, and FIG. 4 is a side view thereof.

The steam/water separator 4 is suspended from the turbine building 15 by a hanger 17 via a U-shaped band 16.

FIG. 5 and FIG. 6 show the movement state of the steam/water separator when the turbine is in operation.

Due to the thermal expansion of the cross-around pipes 12 and 13, the steam/water separator 4 moves horizontally by 50 mm. This movement is absorbed by the shape of the hanger 17.

Figure 7 shows the installed state of the drain level detector.

The steam 2a that has worked in the high-pressure turbine 3 and contains a large amount of water is separated by a drain 18 while passing through the steam separator 4, and is supplied to the low-pressure turbine 5 as steam 2b that is close to dry steam. Separated drain 1
8 is collected in a drain tank 9. The drain level 19 is maintained at a constant level on the lower side of the drain tank 9, and when the level reaches a specified level or higher, the drain level 19
The water is supplied to the feed water superheater 8 as water.

In the unlikely event that the drain level 19 rises above a certain level, the separated drain 18 will be carried into the low-pressure turbine 5 along with the steam 2b (carry over), causing problems such as reduced efficiency, erosion, and divergence of the rotor blades. becomes. Furthermore, an increase in the amount of accumulated drain increases the load applied to the hanger 17, resulting in the uneconomical need to make the turbine building 15, hanger 17, and other equipment stronger than necessary.

A drain level detector 11 is installed to prevent the above-mentioned problems and waste. drain level 19
When the level reaches a certain position, it is detected by the level detector 11, an alarm is generated, and the operation of the power plant is stopped.

As described above, the drain level detector 11 is connected to the lower part of the body of the steam separator 4 and the drain tank 9 in the vicinity of the connection portion thereof with the two pipes 20 .

The weight of the level detector 11 cannot be supported by the two pipes 20, so a separate pedestal 21 is required. Since it is technically impossible to install a pedestal for a level detector that is placed separately from the device 4, a configuration that allows it to move together with the steam separator 4 is required. That is, the pedestal 21 that is integrated with the steam/water separator 4 is required.

However, since the pedestal 21 is in the atmosphere, there is no thermal expansion even during turbine operation, but the steam/water separator 4 does undergo thermal expansion, so the pedestal 21 integrated with the steam/water separator 4 can absorb the difference in thermal expansion. It is necessary to have a structure.

As a structure capable of absorbing the difference in thermal expansion, FIG. 8 and FIG. 9, which is viewed from the side, can be considered, but this structure also has drawbacks. That is, the structure is such that an independent pedestal 22 is attached to the drain tank 9 for each level detector 11, but there is a drawback that the pedestal 22 itself cannot be large enough to be used as a cantilever. I need. The reinforcement 23 deforms as shown by the two-dot chain line 23a due to the thermal expansion of the drain tank 9, and the internally generated stress increases, so it has to be made strong.

Furthermore, the pedestal of this drain level detector is provided for each of the multiple drain level detectors in order to prevent the generation of thermal expansion differences, so it is large-scale and requires a large pedestal setting space. There was a drawback that it required

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a safe, reliable and good support device for a drain level detector that generates little thermal stress and requires a small installation space.

[Summary of the invention]

That is, the present invention includes a pedestal for a drain level detector, a pedestal placed below the level detector and supporting the level detector, and a pedestal placed at both ends of the pedestal to connect the pedestal to a steam/water separator. The plate is formed of a flexible plate material into a substantially U-shape, and both ends of the U-shape on the open leg side are fixed to the side wall of the steam/water separator, and the opposite The side ends are fixed to the pedestal to achieve the intended purpose.

[Embodiments of the invention]

FIG. 10 shows the entire mounting state of the level detector pedestal of the device of the present invention. The pedestal is composed of a plate 24 and a pedestal 25.

The plate 24 is made of a flexible plate material,
And it is formed as follows. That is, the 12th
As is clear from the figure, it is formed almost in a U-shape,
Both ends of the U-shaped open leg side are fixed to the side wall of the steam/water separator. Also, the side of the U-shaped legs that is not open is the pedestal 25.
is fixed to.

FIG. 11, FIG. 12, and FIG. 13 show the thermal expansion difference absorption state. That is, plate 24
absorbs the difference in thermal expansion by bending, as shown by the two-dot chain line.

In FIGS. 11 and 12, when the steam separator 4 thermally expands, the initially set plate 24 is bent like plates 24a and 24b to absorb the difference in thermal expansion. In this case the corner 26 of the plate 24
If the plate 24b is rounded, it has the effect of alleviating the concentration of stress that occurs when the plate 24b is bent.

FIG. 13 shows that when the difference in thermal expansion of the steam/water separator 4 is large, the plate 24c is set to be bent in advance by the amount of thermal expansion, and when the steam/water separator 4 expands, almost no deflection occurs in the plate 24a. Therefore, there is an effect that almost no stress is generated.

〔Effect of the invention〕

According to the present invention, it is possible to provide a safe and reliable pedestal for a drain level detector that generates little thermal stress and requires a small installation space.

[Brief explanation of drawings]

Figure 1 is a system diagram of a nuclear power plant, Figure 2 is a diagram of a nuclear power plant.
Figures 3 to 6 are perspective views of the main equipment shown in the figure, Figures 3 to 6 are installation structure diagrams of a steam/water separator, Figure 7 is an installation structure diagram of a drain level detector, and Figures 8 and 9 are conventional 10 to 13 are structural diagrams of the pedestal of the level detector of the present invention. 1... Nuclear reactor, 3... High pressure turbine, 4... Steam water separator, 21... cradle.

Claims (1)

[Scope of Claims] 1. A support device that supports a drain level detector provided in a steam/water separator for a nuclear turbine on a side of the steam/water separator via a pedestal, comprising the steps of: , a pedestal disposed below the level detector and supporting the level detector; and plates disposed at both ends of the pedestal for supporting the pedestal on the steam/water separator, and The plate is formed of a flexible plate material into a substantially U-shape, and both ends of the U-shape on the open leg side are fixed to the side wall of the steam water separator, and the opposite end is fixed to the pedestal. A support device for a steam/water separator drain level detector, characterized in that: