JPS6251437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an improvement in the support structure of a pressure vessel, such as a reactor vessel or a spent fuel storage tank, in nuclear reactor equipment, which houses reactor core components together with a coolant such as liquid metal sodium. Regarding.

This type of pressure vessel support structure supports the pressure vessel's own weight and the load of heavy objects such as core components including coolant and fuel assemblies, and is designed to withstand earthquake resistance and thermal stress associated with operation. Sufficient safety and reliability are required.

On the other hand, a conventional support structure for a pressure vessel is as shown in FIG. In the figure, reference numeral 1 denotes a pressure vessel containing core components 2 and coolant 3, and is equipped with a shield peg 4 on the top of the pressure vessel. Fuel assemblies are taken in and out. The pressure vessel 1 also has a flange portion 5, and is fixedly supported on the foundation surface of a pedestal 6 made of concrete foundation as described below. That is, the support structure includes a sole plate 8 installed and fixed to the pedestal 6 with foundation bolts 7, and a flange portion 5 is placed on this sole plate 8 to support the entire load of the pressure vessel 1. The sole plate 8 and the flange portion 5 are firmly and integrally connected. Furthermore, the stiffening plug 4 is supported on the sole plate 8 via a supporting spacer 10 on the outer peripheral side of the flange portion 5, and is fixed to the sole plate 8 with a plug fixing bolt 11.

By the way, in the above configuration, the pressure vessel 1 and the shield plug 4 are made of stainless steel, whereas the sole plate 8 is made of iron for ordinary construction, and the coefficients of thermal expansion of the two are different. For this reason, during operation, a difference in thermal expansion occurs as the temperature rises, and due to this difference in thermal expansion, excessive thermal stress is applied to the base of the flange portion 5 or the bolt 9 of the pressure vessel 1. 9 may be damaged. Further, when an earthquake occurs, the horizontal load acting on the bolt 5 becomes excessive, and if this continues, there is a risk that the bolt 5 will not be able to withstand the strength. In addition, since the pressure vessel 1 and the shielding plug 4 are individually fixed to the sole plate 8 via bolts 9 and 11, horizontal displacement and rotational displacement due to thermal expansion, earthquakes, etc. described above are independent. There is also a risk of fuel damage due to an unreasonable load being applied to the fuel while it is being handled.

In view of the above points, the present invention has been made with the object of eliminating the conventional drawbacks and providing a support structure for a pressure vessel that has higher reliability against thermal stress, earthquakes, etc.

The present invention will be described in detail below based on illustrated embodiments.

In FIGS. 2 and 3, in the present invention, the first
Compared to the conventional structure shown in the figure, an intermediate sole plate 12 and a radial key 13 are newly added.
The intermediate sole plate 12 is placed on the sole plate 8, and is firmly fixed to the sole plate 8 by a fixing bolt 14 screwed through the pedestal 6 and the sole plate 8 from below. Further, the radial key 13 can slide along a key groove 15 formed on the upper surface of the intermediate sole plate 12, and the radial key 13 is coupled to the lower surface of the flange portion 5 of the pressure vessel 1.
The load is supported to the intermediate sole plate 12 via the intermediate sole plate 12. And from below, the intermediate sole plate 12,
The three parts are fixed together by a container fixing bolt 9 that passes through the radial key 13 and is screwed into the flange portion 5. Moreover, in particular, a bolt hole 16 having a diameter larger than that of the bolt 9 in the radial direction is bored in the intermediate sole plate 12, and the bolt 9 passes loosely through this port hole 16. Further, the upper shield plug 4 is directly fixed to the flange portion 5 via a plug fixing bolt 11. In this case, the positions of the plug fixing bolts 11 are shifted from each other to avoid interference with the container fixing bolts 9,
For example, it is preferable to set it in the middle of the pitch of the bolt 9 on the circumference. In addition, the container fixing bolts 9 should be selected to be as long as possible so as to absorb horizontal displacement due to differences in thermal expansion and prevent excessive concentrated loads from being applied to the bolts 9. Based on this bolt dimension, the intermediate sole plate Twelve thickness dimensions are determined.

Now, with the support structure described above, when thermal stress due to thermal expansion difference or horizontal load during an earthquake is applied, the pressure vessel 1 can move on the intermediate sole plate 12 via the radial key 13, and the pressure vessel 1 can move on the intermediate sole plate 12 via the radial key 13. The fixing bolt 9 can be bent in a cantilever manner using the bolt head as a fulcrum within the large-diameter bolt hole 16 into which the fixing bolt 9 is loosely fitted.
The horizontal load can be safely absorbed without applying an excessive load to the base of the bolt 9 or the bolt 9. Furthermore, since the intermediate sole plate 12 is interposed between the sole plate 8 and the pressure vessel 1 and the sole plate 12 is fixed individually with bolts 9 and 14, the load applied to each bolt 9 and 14 is distributed, which increases safety accordingly. It increases, and in addition, it is hard plug 4
Since it is integrally connected to the pressure vessel 1, there is no risk of relative displacement between the two as in the conventional case.
a sealing mechanism inserted between the container 1 and the plug 4;
Also, it is possible to avoid applying an unreasonable load to the fuel being handled.

Thus, according to the present invention, it is possible to provide a highly reliable support structure for a pressure vessel that can safely absorb thermal stress caused by a difference in thermal expansion and exhibits excellent earthquake resistance.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional pressure vessel support structure, FIG. 2 is a sectional view of an embodiment of the present invention, and FIG. 3 is an enlarged view of the main parts of FIG. 2. 1: Pressure vessel, 4: Shrink plug, 5: Flange, 6: Foundation pedestal, 8: Sole plate, 9: Vessel fixing bolt, 11: Plug fixing bolt, 12: Intermediate sole plate, 13: Radial key , 14: Fixing bolt of intermediate sole plate, 16: Bolt hole for container fixing bolt drilled in intermediate sole plate.

Claims (1)

[Claims] 1.Equipped with a sole plate installed on the foundation surface, an intermediate sole plate placed on the sole plate and fixedly supported with bolts, and a radial key inserted between the intermediate sole plate and the flange of the pressure vessel, The pressure vessel, which supports the load on the intermediate sole plate via the radial key, is fixed to the intermediate sole plate along with the radial key using a container fixing bolt that is installed through a large diameter bolt hole drilled in the intermediate sole plate, and the plug is also fixed. A support structure for a pressure vessel in nuclear reactor equipment, characterized in that an upper shield plug of the pressure vessel is integrally connected to a flange portion of the pressure vessel via bolts.