JPS60120293A - Earthquake-resistant support structure of apparatus installed in nuclear reactor - 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] The present invention relates to an earthquake-resistant support structure for equipment installed in a nuclear reactor.

Equipment installed in a nuclear reactor, such as an intermediate heat exchanger in a tank-type fast breeder reactor, that is suspended from the upper part of the reactor vessel may require seismic support for the lower part as well.

However, in such equipment, relative displacement occurs between the equipment and the structure on the reactor vessel side due to thermal expansion due to temperature rise from installation to rated operation. The distance between the equipment and the structure changes, resulting in the equipment not functioning properly in the event of an earthquake, or placing an unreasonable load on the equipment.

Therefore, seismic support for such equipment must have a structure that absorbs relative displacement due to thermal expansion and has the necessary damping force in the event of an earthquake. Furthermore, since it will be installed in a nuclear reactor for a long period of time, it must have a structure that can withstand the coolant, temperature, and radiation inside the reactor, and that can be easily removed in the event of an emergency.

The present invention attempts to solve such a need by attaching a dashpot-type vibration isolator using reactor coolant as a working fluid to equipment installed in a nuclear reactor.

An example of an earthquake-resistant support structure for equipment installed in a nuclear reactor according to the present invention will be explained below, taking as an example the case of an intermediate heat exchanger for a commercial speed breeder reactor. In the wJ1 diagram, 1 is a reactor vessel, 2 is a roof slab, and 3 is an intermediate heat exchanger, which is suspended from the roof slab 2 via a flange 4 and immersed in liquid sodium in the reactor vessel 1. There is. An electric vibration isolator 5 is provided at the bottom of the intermediate heat exchanger 3, and the reactor vessel 1
It is supported by a support structure 6 fixed to the side. The vibration isolator 5 is installed at the bottom of the intermediate heat exchanger 3 as shown in FIG.
A piston 9 having a rod 8 on both sides j is provided in a cylinder T attached with @L so as to be movable left and right, and a rod 80 passing through a cover 10 at both ends of the cylinder 7 has a backing plate 11 at both ends.
A labyrinth structure 12 is formed on the outer peripheral surface of the piston 9 and the inner peripheral surface of the rod through hole of the cover iu of the cylinder 7, and a vacuum line 13 is connected to one chamber of the cylinder 7. Reference numeral 13 leads the reactor to the outside of the reactor vessel 1 along the intermediate heat exchanger 3 and communicates with a vacuum pump (not shown). The length from the backing plate 11 at one end of the rod 8 to the backing plate 11 at the other end is slightly shorter than the inner diameter of the support structure 6 fixed to the reactor vessel 1.

In addition, after the intermediate heat exchanger 3 is installed and before operation [yA
When the sub-furnace vessel 1 is filled with liquid sodium, which is a coolant, a vacuum pump (not shown) performs evacuation through the evacuation line 13t connected to the cylinder 1, and the cylinder 7 is evacuated with covers at both ends. The labyrinth structure 12 between the rod 8 and the labyrinth structure 10 is gradually filled with IJum,
Vacuum line 13 above the roof slab 2 after filling
The stop valve 14 is closed.

Next, the operation of the seismic support structure having the above configuration will be explained.

The intermediate heat exchanger 3 undergoes relative displacement in the radial direction of the reactor vessel 1 and the reactor vessel due to its own weight and thermal expansion due to temperature rise. Therefore, the center of the intermediate heat exchanger 3 and the support structure 6 are displaced relative to each other as the temperature rises from the time of installation to the time of low-temperature shutdown and the time of rated operation.

When the intermediate heat exchanger 3 moves due to thermal expansion in this way, the cylinder 7 of the vibration isolator 5 attached to the bottom of the intermediate heat exchanger 3 moves. As a result, liquid sodium moves between the cylinder 7 and the piston 9 little by little, without generating any resistance force.
moves relative to the piston 9. During an earthquake, cylinder 7 moves rapidly, so liquid sodium flows into cylinder 7.
A large resistance force is generated when moving between the piston 9 and the piston 9,
It acts as a damping force for the intermediate heat exchanger 3.

The vibration isolator 5 in the seismic support structure of the above embodiment is attached to the bottom of the intermediate heat exchanger 3, but if it is attached at a symmetrical position on the lower side of the intermediate heat exchanger 3, Fourth
The vibration isolator 5' has a structure as shown in the figure. That is, the cylinders 7' are completely fixed at symmetrical positions on the lower side surface or the lower end surface of the intermediate heat exchanger 3Q, and the rods 8' are installed inside the cylinders 7' on the other side.
A piston 9' is slidably provided to the south of the cylinder 7'.
A cover plate 11' is fixed to the tip of the rod 8' that has passed through the cover 1u' at the other end, and a labyrinth structure 12 is formed on the outer peripheral surface of the piston 9' and the inner peripheral surface of the rod through hole of the cover 10'. A vacuum line 13 is connected to the chamber on the intermediate heat exchanger 3 side of the cylinder 1', and the vacuum line 13 is connected to the outside of the reactor vessel 1 along the outside or inside of the intermediate heat exchanger 3 as in the previous embodiment. The cylinder 7' is connected to a vacuum pump (not shown), and a 15' spring is inserted into the chamber on the intermediate heat exchanger 3 side of the cylinder 7', and the piston 9' is constantly pushed with a constant force. Tip plate 11' support structure 6
There is a structure that corresponds to that and one without.

In this embodiment as well, when the intermediate heat exchanger 3 moves due to thermal expansion, the cylinder 1' of the vibration isolator 5' attached to the lower side surface of the intermediate heat exchanger 3 moves.

As a result, liquid sodium moves little by little between the cylinder tab' and the piston 9', and the cylinder T' moves relative to the piston 9' without generating any resistance. Since the cylinder 7' moves rapidly during an earthquake, a large resistance force is generated when the liquid sodium moves between the cylinder 7' and the piston 9', which acts as a damping force on the intermediate heat exchanger 3.

Note that the mounting position and direction of the vibration isolator is not limited to the above example, and it is effective for earthquake resistance even if it is mounted in the moving direction of the intermediate heat exchanger or in the right angle direction. The seismic support structure for equipment installed in a nuclear reactor according to the present invention includes a dashpot-type vibration isolator that uses reactor coolant as the working fluid inside the reactor! Since it is attached directly to the equipment and the support structure is covered with a corresponding gold film inside the reactor, the vibration isolator can absorb the relative displacement between the equipment and the support structure due to thermal expansion, and it also provides protection in the event of an earthquake. It can be said to be an extremely effective earthquake-resistant support structure because a large resistance force is generated in the vibrator, which acts as a damping force for the equipment installed inside the reactor. Furthermore, since the vibration isolator in the seismic support structure of the present invention has a simple dashpot-type structure using reactor coolant as the working fluid as described above, it operates reliably and does not malfunction. Since it is directly attached to the equipment installed in the reactor, it has the advantage of being able to inspect the installed equipment when it is taken out.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of an earthquake-resistant support structure for equipment installed in a nuclear reactor according to the present invention, FIG. 2 is an enlarged vertical cross-sectional view of FIG. 1, and FIGS. FIG. 7 is an enlarged vertical cross-sectional view of main parts showing all other embodiments of the earthquake-resistant support structure. 1... Reactor vessel 2... Roof slab 3...
Intermediate heat exchanger 4...Flange 5, 5'...Vibration isolator 6...Support structure 7,7'...Cylinder 8,
8'...Rod 9, 9'...Piston 10,
1 (j'... Cover 1i, ii'... Backing plate 12... Labyrinth structure 13... True nitrogen drawing line 14... Stop valve 15... Spring Figure 1 Figure 2 Figure 3 figure

Claims (1)

[Claims] A dashpot-type vibration isolator that uses reactor coolant as a working fluid is attached to equipment installed in a nuclear reactor, and a support structure is provided in the reactor correspondingly. seismic support structure.