JPH0247719B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the internal structure of a nuclear reactor containment vessel, and more particularly to the steel structures installed in the reactor containment drywell, including piping supports, equipment supports, pipe whips, etc. This invention relates to improvements in support structures that support various steel structures such as structures and maintenance platforms.

Figure 1 shows the installation structure of a conventional reactor containment vessel and its peripheral equipment.

The reactor containment vessel 1 includes a dry well 3 that surrounds the reactor pressure vessel 2, and a pressure suppression chamber 4 that stores pool water 5 to suppress the pressure rise in the containment vessel 1 in case of an accident in which loss of coolant occurs. It is composed of. The dry well 3 and the pressure suppression chamber 4 are separated by a diaphragm floor 6, and both chambers 3,
4 are communicated via a vent pipe 7 installed on the diaphragm floor 6. Further, inside the dry well 3, steel structures 8 such as piping supports, equipment supports, pipe whip structures, and maintenance platforms are installed.

FIG. 2 is a sectional view taken along the line AA in FIG. 1, showing the overall arrangement of the vent pipe 7. As is clear from the figure, the vent pipe 7 is connected to the diaphragm floor 6.
A large number of them are placed on average on the floor.

FIG. 3 is a detailed view showing the installation state of the vent pipe 7;
FIG. 4 is a view taken along the line B--B in FIG. 3. As is clear from FIG. 3, the vent pipe 7 is buried in the steel concrete part of the diaphragm floor 6, and the opening of the vent pipe 7 located on the drywell 3 side is exposed to high temperature during a coolant loss accident. A jet deflector 9 made of a circular thick steel plate is provided for the purpose of preventing the high-pressure jet flow from flowing into the pressure suppression chamber 4 all at once and impairing the condensation effect. Furthermore, as is clear from FIGS. 3 and 4, the jet deflector 9 is supported by a plurality of vertical ribs 10, and therefore, in the event of a loss of coolant accident, the high temperature and high pressure jet flow is , flows into the vent pipe 7 through between the jet deflector 9 and the longitudinal rib 10, and the pool water 5 in the pressure suppression chamber 4
It is released and condenses inside.

FIG. 5 is a longitudinal sectional view showing the installed state of the steel structure 8 installed in the dry well 3, and the steel structure 8 is supported by metal fittings 11 embedded in the steel concrete part of the diaphragm floor 6. has been done.

The installation structure of the conventional reactor containment vessel and its peripheral equipment is as described above, but the diaphragm floor 6 that partitions the dry well 3 and the pressure suppression chamber 4 of the containment vessel 1 has a very large Not only are the amount of reinforcing bars placed, but as shown in Figure 2,
A large number of vent pipes 7 are also arranged, and as shown in FIG.
Therefore, the reinforcement structure of the diaphragm floor 6 becomes complicated, and it cannot be denied that the design adjustment prior to on-site work is extremely complicated. In addition, during on-site work, reinforcement work for the diaphragm floor 6, installation work for the vent pipe 7, and installation work for the metal fittings 11 must be performed concurrently and in parallel, so the reinforcement work for the diaphragm floor 6 must be done in parallel. The number of connections between each member increases, and the work itself becomes extremely complex.

The present invention has been made in consideration of the above points, and its purpose is to simplify the design adjustment prior to constructing the diaphragm floor of the reactor containment vessel, and also to simplify the design adjustment prior to constructing the diaphragm floor of the reactor containment vessel. , it is possible to reduce the number of connections between each component buried in the diaphragm floor compared to the conventional method, simplify the construction work itself, and furthermore, it is possible to easily change the piping route inside the dry well after the diaphragm floor is constructed. It is an object of the present invention to provide an improved support structure for a steel structure inside a drywell, which is capable of providing a support structure for a steel structure within a drywell.

In order to achieve the above object, the present invention communicates a dry well surrounding a reactor pressure vessel and a pressure suppression chamber in which cooling water is stored via a plurality of vent pipes installed on a diaphragm floor. In the structure of the reactor containment vessel, piping supports, equipment supports, and
This system is characterized by a steel structure such as a pipe whip structure and a maintenance platform mounted on a jet deflector installed at the opening of the vent pipe on the dry well side.

Hereinafter, the present invention will be explained based on FIG. 6. The figure is a longitudinal cross-sectional view of the main part (steel structure support part in the dry well) showing one embodiment of the present invention, and the reference numeral 6 is A diaphragm floor, 7 a vent pipe communicating the dry well 3 and the pressure suppression chamber 4, 9 a jet deflector installed at the dry well side opening of the vent pipe 7, 10 a vertical rib supporting the jet deflector 9, 12 8 shows a support member welded to the jet deflector 9, and 8 shows a piping support and other steel structures connected to the support member 12 by welding. The gist is that the installed steel structure 8 is attached onto a jet deflector 9 installed at the dry well side opening of the vent pipe 7.

Therefore, according to the present invention having the above configuration, the embedded fitting 11 for supporting the steel structure 8 in the diaphragm floor 6 is installed as shown in FIG.
Since it is no longer necessary to install a diaphragm floor 6, the design adjustment prior to constructing the diaphragm floor 6 is easier than before, and during on-site work, the number of connections between the various parts buried in the diaphragm floor 6 is reduced compared to before. The construction work itself can also be simplified.

Moreover, in the present invention having the above configuration,
Since the steel structure 8 can be appropriately selected from a large number of jet deflectors 9 arranged on the diaphragm floor 6 and installed at any location, the piping can be installed at any location after the construction of the diaphragm floor 6 is completed. Even if there is a change in the route, the route can be easily changed, and there can be some leeway in changing the design of the piping route after the diaphragm floor construction is completed.

As mentioned above, a large number of jet deflectors 9 are arranged in the dry well of the reactor containment vessel, so in the present invention, even if the steel structure 8 does not pass directly above the jet deflectors 9, Even in this case, if a support beam is constructed between the jet deflectors 9 located near the steel structure 8, the steel structure 8 can be easily supported on this beam.

As described in detail above, according to the present invention, the design adjustment prior to constructing the diaphragm floor of the reactor containment vessel is simpler than before, and even during on-site work, each member installed on the diaphragm floor can be adjusted easily. This is an improved design that reduces the number of joints than before, simplifies the construction work itself, shortens the construction period, and makes it easier to change the piping route inside the dry well after constructing the diaphragm floor. A support structure for a steel structure in a dry well can be obtained.

[Brief explanation of the drawing]

Figures 1 to 5 show the installation structure of a conventional reactor containment vessel and its peripheral equipment, Figure 1 is an explanatory diagram of the internal structure of the entire containment vessel, and Figure 2 is A-A in Figure 1.
A sectional view, FIG. 3 is a longitudinal sectional view showing the installation state of the vent pipe that communicates the dry well and the pressure suppression chamber,
FIG. 4 is a view along the line B-B in FIG. 3, and FIG. 5 is a vertical cross-sectional view showing the installed state of the steel structure inside the dry well.
FIG. 6 is a longitudinal cross-sectional view of essential parts showing one embodiment of the present invention. 3...Dry well, 4...Pressure suppression chamber, 6...
...Diaphragm floor, 7...Vent pipe, 8...
Steel structure, 9... Jet deflector, 10...
...Vertical rib, 12...Support member.

Claims (1)

[Claims] 1 A dry well surrounding the reactor pressure vessel,
In the structure of a reactor containment vessel that communicates with a pressure suppression chamber that stores cooling water inside through multiple vent pipes installed on the diaphragm floor, piping supports and equipment supports installed inside the dry well. , pipe whip structures, maintenance platforms, and other steel structures.
A support structure for a steel structure installed in a reactor containment vessel drywell, characterized in that the structure is installed on a jet deflector installed at the drywell side opening of a vent pipe.