JPS62276495A - Fast breeder 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] 3. Detailed description of the invention [Industrial application field] The present invention relates to fast breeder reactors.

[Conventional technology]

FIG. 4 shows a layout diagram of the primary cooling system of a conventional fast breeder reactor. 1 is a reactor vessel, 2 is an intermediate heat exchanger, 3 is a main circulation pump, and inlet piping 4, They are connected by a crossover leg pipe 5 and an outlet pipe 6 to form a primary cooling system. Although not shown, the intermediate heat exchanger 2 is connected to piping of a secondary cooling system.

The reactor vessel 1 is firmly fixed to a building in order to maintain safety even in the event of an earthquake, and the intermediate heat exchanger 2 and main circulation pump 3 are also conventionally fixed to the building.

A fast breeder reactor has an inlet temperature of around 350℃ and an outlet temperature of 50℃.
Since it is operated at a high temperature of around 0℃, the inlet piping 4, crossover leg piping 5, and outlet piping 6 that connect them are designed to keep the stress generated on the piping itself and the equipment attachment part of the piping due to expansion within the allowable value. , is routed as shown in the figure. Such a configuration of the primary cooling system not only requires longer piping, but also increases the number of supports associated with the piping, and also increases the installation space, resulting in an increase in construction costs.

FIG. 5 shows a conventional example designed to improve the above-mentioned problems. This was modeled after the configuration of the primary cooling system of a light water-cooled nuclear reactor; the reactor vessel 1 is firmly fixed to the building, but the intermediate heat exchanger 2 and main circulation pump 3 are suspended. Hang it at 7.

[Problem that the invention seeks to solve]

Since the connecting portion 8 of the weighing rod 7 with the 8iWi and the connecting portion 9 with the building are supported by pins, the intermediate heat exchanger 2 and the main circulation pump 3 will move freely when only lightly pushed. Therefore, even if these devices are connected by the shortest distances such as inlet piping 4, crossover leg piping 5, and outlet piping 6, the horizontal thermal expansion displacement can be escaped by the free displacement of the devices, so vertical thermal expansion countermeasures can be taken. All you have to do is think about it, and you can make a big rationalization.

However, in fast breeder reactors, the rigidity of piping is lower than in light water-cooled reactors, and the main circulation pump needs to be a free-level type, so taking into account liquid level fluctuations in the system, the axial length of the pump has to be increased considerably. If the main circulation pump is supported loosely, it will cause slight vibrations that exceed the permissible amplitude of the pump during low-speed rotation, causing problems with its feasibility.
I have not yet been hired.

The present invention was made in view of the above-mentioned circumstances, and since it is essential to shorten the piping of the primary cooling system in order to realize a rational fast breeder reactor, the above-mentioned structure has been improved. .

[Means for solving problems]

The main circulation pump body was firmly fixed to the building to prevent the occurrence of minute vibrations, and only the pump container, which forms the boundary between the coolant, was left freely supported. For this purpose, install an expansion joint between the pump container body and the support flange so that the pump container can move vertically and horizontally. This causes a relative displacement between the pump body and the pump container, creating problems with sealing at the inlet and outlet, but this can be resolved by using the conventional combination of carrier ring and piston ring. did.

Therefore, in the fast breeder reactor of the present invention, the pump body of the main circulation pump is fixed and suspended on a deck, the pump container is movably suspended on the deck via an expansion joint, and a carrier is attached to the outer periphery of the pump body. A ring is fitted to seal a predetermined gap provided between the pump body and the pump container against pump discharge pressure, and the intermediate heat exchanger is movably suspended from the deck using a hanging rod.

[For production]

The intermediate heat exchanger and the pump vessel of the main circulation pump can move freely to absorb the thermal expansion of the piping. Furthermore, since the pump body is firmly fixed to the deck, slight vibrations do not occur.

〔Example〕

FIG. 1 is a longitudinal sectional view of a fast breeder reactor showing an embodiment of the present invention, FIG. 2 is a plan view of the fast breeder reactor, and FIG. 3 is an enlarged longitudinal sectional view of a carrier ring. 1 is a reactor vessel, 2 is an intermediate heat exchanger, 3a is a pump vessel of a main circulation pump, and 10 is a main circulation pump body. In this example, the reactor vessel is
The deck 11 is fixedly supported by the building 1.
2 is firmly fixed. The intermediate heat exchanger 2 is suspended from the deck 11 by four hanging rods 7, and the upper and lower fixing parts 8 and 9 of the hanging rods 7 are supported by pins.

Also, the pump container 3aζ of the main circulation pump is connected to the flange 13 fixed to the deck 11 with a telescopic joint 14 attached to the upper part. The telescopic joint 14 is of a so-called universal type in which it is divided into upper and lower parts and 9 short pipes 15 are installed between them so that there is no problem even if the pump container 3 of the main circulation pump moves from side to side. Also, the circumferential gap between the pump container 3a of the main circulation pump and the main circulation pump main body 10 is the pump volume 1 of the main circulation pump.
An appropriate gap is provided so that the i33a can move freely, and a carrier ring 16 is installed as a seal against the pump discharge pressure. An enlarged view of the carrier ring 16 is shown in FIG. 3, but basically a piston ring 17 is fitted onto the outer periphery of the carrier ring 16, and a screw!・Nring 1
7 is in close contact with the inner circumference of the main circulation pump/container 3a,
Seal. The carrier ring 16 has a structure in which the piston ring 17 and the inner periphery of the pump container 3a of the main circulation pump are kept in close contact with the main circulation pump main body 10 and can move freely in the horizontal direction. Since the lower surface and the upper and lower surfaces 9 of the circumferential groove provided in the main circulation pump main body 10 slide closely together, a sealing effect is achieved.

In order to ensure this sliding action, a suitable eight-face facing is applied to the sliding surface.

Therefore, the structure maintains the sealing performance even if the main circulation pump main body 10 and the pump container 3a of the main circulation pump are vertically and horizontally displaced relative to each other.

4.5 and 6 are connected to their respective devices over short distances by inlet piping, crossover leg piping, and outlet piping, respectively. FIG. 2 shows its planar arrangement. This is 4
This is an example of a loop. 18 is a reverse ratio valve.

In this embodiment, the suction port 19 of the outlet pipe 6 is made flat with a curvature in order to minimize the diameter of the reactor vessel 1, and the intermediate heat exchanger 2 is made into a flat shape with a curvature in order to minimize the diameter of the reactor vessel 1. In order to minimize the amount of displacement, the outlet piping 6 may be pulled out from the boundary plate 20 provided on the ceiling of the reactor vessel 1, or the deck 11 may not only be used to support the reactor vessel 1, but also to make the entire structure more compact.
Support for the intermediate heat exchanger 2 and the pump volume fi3a of the main circulation pump is also shared.

〔Effect of the invention〕

Since the intermediate heat exchanger 2 and the pump container 3a of the main circulation pump move freely, they can absorb thermal expansion of the piping.

However, since the pump body 10 is firmly fixed to the deck 11, no problem-prone vibrations occur.

The primary coolant enters the intermediate heat exchanger 2 from the suction port 19 through the outlet piping 6, is heat removed in the secondary system, and passes through the crossover leg piping 5 to the lower part of the pump container 3a of the main circulation pump. Go into the room. Since the pump impeller is provided in the 0 section, the coolant is pressurized and pushed out to the d section. Since the upper and lower parts of the d section are sealed by the carrier ring 16, the coolant is forced into the inlet side of the reactor vessel 1 through the inlet pipe 4.

Since the upper part of the pump container 3a of the main circulation pump is in an atmosphere of relatively low-temperature cover gas, it is easy to ensure the integrity of the expansion joint 14, and even if a crack should occur, the cover gas will simply leak out. There will be no coolant leakage accident. Further, even if the expansion joint 14 is cut into a guillotine shape, the dead weight of the pump container 3a of the main circulation pump is supported by the inlet pipe 4 and the crossover leg pipe 5, so a coolant leakage accident will not occur. Therefore, it is possible to provide a safe and rational fast breeder reactor.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a fast breeder reactor showing an embodiment of the present invention, FIG. 2 is a plan view of the fast breeder reactor, FIG. 3 is an enlarged longitudinal sectional view of a carrier ring, and FIGS. The figure is a layout diagram of the primary cooling system of a conventional fast breeder reactor. 1 Reactor vessel, 2-Intermediate heat exchanger, 3 Main circulation pump, 3a Main circulation pump pump vessel, 7 - Hanging rod, 10 Main circulation pump body, 11 Deck, 14 - Expansion joint, 16 Carrier ring, Patent Applicant: Power Reactor and Nuclear Fuel Development Corporation
Mitsubishi Atomic Crab Industry Co., Ltd. Representative Patent Attorney Hideaki Sato $4n

Claims (1)

[Claims] The pump body of the main circulation pump is fixed and suspended on the deck, and the pump container is movably suspended on the deck via an expansion joint, and a carrier ring is fitted around the outer periphery of the pump body, and the pump body and the pump container A fast breeder reactor characterized in that a predetermined gap provided between the deck and the pump is sealed against pump discharge pressure, and an intermediate heat exchanger is freely suspended from the deck by a hanging rod.