JPH0225196Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pressurizer, particularly a pressurizer suitable for use in a pressurized water nuclear reactor.

An example of a conventional pressurizer of this type is shown in Figures 1 to 3.
As shown in the figure and shown in FIG. 1, a large number of heaters 02 are provided protruding from the lower part of the container 01 extending in the vertical direction, and spray nozzles 03 are provided at the upper part of the container 01.
is installed. During operation, this pressurizer forms a free liquid level in the container 01, increases the steam pressure in the gas phase by heating the liquid with the heater 02, and injects cold water from the spray nozzle 03. Condenses steam to reduce steam pressure in the gas phase. In this way, by increasing or decreasing the vapor pressure in the gas phase, the pressure in the liquid phase and the primary system loop communicating therewith is adjusted.

The heater 02 is connected to the container 01 as shown in FIG.
The heater 02 is vertically inserted into the container 01 through the housing 05 welded to the lower end plate 04 of the heater 02.
The socket 06 and housing adapter 07 are welded. As shown in FIG. 3, the heater 02 and the housing adapter 07 are arranged in multiple concentric circles to form one group, and are surrounded by a support skirt 08 that supports the pressurizer. Therefore, when replacing the heater 02, there is not enough work space to cut the welded part between the heater 02 and the adapter 07, and weld the adapter 07 and the newly inserted heater 02. The work is not easy because of the high radiation exposure.
In addition, if a fire occurs near the connection between the heater 02 and the housing 05, the support skirt 08
There is concern that most of the heaters 02 arranged inside the pressurizer will be damaged and the safety of the pressurizer will be compromised. Also, since a large number of heaters 02 are arranged in a narrow space inside the support skirt 08, the heaters 02
In order to cool the joint between the housing 05 and the housing 05, it is necessary to forcibly send air to cool the joint.

The present invention was proposed in order to solve the above problem, and its gist consists of a heater protruding from the lower part of the container extending in the vertical direction, and a sprayer attached to the upper part of the container. In the pressurizer having a nozzle, a support skirt surrounding the container and welded thereto is located near the center of gravity of the pressurizer, and the heater is removed from inside the support skirt.

In the present invention, since the heater is located outside the support skirt, there is no need to forcibly cool the inside of the support skirt, and even if a fire occurs, most of the heaters will not be damaged. Further, since a sufficient working space around the heater can be secured for the work of replacing the heater, etc., the work becomes easier, the work time is shortened, and the amount of radiation exposure received during the work can be reduced. Furthermore, since the support skirt is welded near the center of gravity of the pressurizer, it is possible to reduce the load that tends to overturn the pressurizer in response to lateral seismic loads, and improve reliability in terms of seismic design.

Hereinafter, the present invention will be explained in detail with reference to an embodiment shown in FIGS. 4 to 7.

Figure 4 is a partially cutaway front view showing the
In the figure, hemispherical mirror plates 2 and 3 are attached to the upper and lower ends of a cylindrical body 1 to form a container 40 that extends in the vertical direction. Reference numeral 4 denotes a conical support skirt that surrounds the container 40 and expands downward, the upper end of which is welded to the cylindrical body 1 at a position near the center of gravity of the pressurizer. The support skirt 4 is provided with a plurality of cooling holes 5, and a support plate 6 welded to the lower end of the support skirt 4 is connected to a large number of bolts 7.
It is fixed to the floor by. A spray nozzle 8, a spray nozzle attachment nozzle 9, a safety valve attachment nozzle 27, a relief valve attachment nozzle 10, and a manhole 11 are attached to the upper mirror plate 2. A surge nozzle 12 is attached to the center of the lower mirror plate 3. The inner surface of the container 40 is covered with a stainless steel overlay 13. A baffle plate 14 is attached to a portion that is directly hit by spray water sprayed from a spray nozzle 8 attached to the upper part of the inside of the container 40. 15 is the heater and the fifth
As shown in the figure, the container 40 is divided into two groups 15A and 15B with a plane including the diameter as the boundary. As shown in FIG. 6, each heater 15 passes through the lower end plate 3 and is vertically inserted into the container 40. The socket 20 of the heater 15 is screwed into the housing adapter 16, and a seal ring 21 seals between the two. In order to further improve reliability, a seal weld 27 is applied between the adapter 16 and the socket 20. A heater support plate 22 is attached to a bracket 23 welded to the inner surface of the container 40 by welding or bolts 26,
This heater support plate 22 is provided with a support hole 24 through which the heater 15 passes and a flow passage hole 25 through which the primary cooling water in the container 40 flows.

However, in this pressurizer, since the support skirt 6 surrounds the container 40 and is welded to a position near the center of gravity of the pressurizer, the load that tends to overturn the pressurizer against a lateral seismic load is absorbed. This improves the reliability of seismic design. In addition, since the mounting positions of the support skirt 6 and the heater 15 are separated from each other, sufficient work space can be secured around the mounting part of the heater 15, so that inspection of the mounting part of the heater 15 and replacement work of the heater 15 can be carried out. It has good workability, shortens work time, and reduces radiation exposure. Furthermore, since the heater 15 is screwed into the housing adapter 16, the heater 15 can be easily replaced. The structure allows for easy cutting and rewelding of the seal weld. Since the baffle plate 14 is attached to the portion of the container 40 that comes into direct contact with the spray water, it is possible to prevent the inner surface of the cylindrical body 1 from being damaged by thermal fatigue due to the spray water.

In the above embodiment, a large number of heaters 15 are divided into two groups and inserted vertically into the container through the lower end plate, but as shown in FIGS. 8 and 9, a large number of heaters 15 are 4 groups 15
Divided into A, 15B, 15C, 15D, the same cylinder 1
It can be inserted and attached into the container 40 from all sides so as to extend perpendicularly to the longitudinal axis of the container 40 at the lower part of the container 40 . In this case, the area around the container body 40 can be used as a work space for replacing the heater 15, etc., and the work can be performed in an upright position.

Further, as shown in FIGS. 10 and 11, a large number of heaters 15 are arranged in four groups 15A, 15B, 1.
5C and 15D, each group is fixed by passing through the circular mounting plate 17, and this mounting plate 1
7 may be attached with bolts 19 to mounting seats 18 provided around the lower part of the cylindrical body 1, and the heaters of each group may extend at right angles to the longitudinal axis of the container 40. In this case, by replacing the entire group attached to the circular mounting plate 17 without replacing the heater 15 alone, welding work becomes unnecessary, the four circumferences of the container 40 can be used as a work space, and the It becomes possible to work while maintaining the posture.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional pressurizer, FIG. 2 is an enlarged view of a portion of FIG. 1, and FIG. 3 is a sectional view taken along the - line in FIG. 1. 4 to 7 show one embodiment of the present invention, FIG. 4 is a front view showing a part as a cross section, FIG. 5 is a view taken along the - line of FIG. 4, and FIG. FIG. 7 is a partially enlarged sectional view showing the support structure of the heater, and is a view taken along the - line in FIG. 6. FIG. 8 is a longitudinal sectional view showing another support structure for the heater, and FIG. 9 is a sectional view taken along the line - in FIG. 8. Fig. 10 is a vertical cross-sectional view showing still another support structure of the heater, and Fig. 11 is a longitudinal sectional view showing another support structure of the heater.
FIG. 3 is a sectional view taken along line XI. Container...40, Heater...15, Spray nozzle...8, Support skirt...6.

Claims (1)

[Scope of utility model registration request] In a pressurizer that has a heater projecting from the lower part of a container extending in the vertical direction and a spray nozzle attached to the upper part of the container, a support skirt that surrounds and is welded to the container is located at the center of gravity of the pressurizer. A pressurizer, characterized in that the heater is located nearby and the heater is removed from within the support skirt.