JPH01291195A - Tank type fast breeder - Google Patents

Abstract

PURPOSE:To reduce the entrainment of cover gas caused by the generation of an unstable eddy by placing plural intermediate heat exchangers, and plural main circulating pumps in a nuclear reactor container, so as to become a rotation symmetry in the peripheral direction. CONSTITUTION:In a nuclear reactor container 1, plural intermediate heat exchangers 2a-2d are placed in a specular surface symmetry around a rotary plug 16. Also, main circulating pumps 3a-3d are provided by two sets each on both sides of the heat exchangers 2b, 2d. As a result, the arrangement constitution of the heat exchangers 2a-2d and the pumps 3a-3d in the furnace forms a 180 deg. rotation symmetry shape. According to such a constitution, since a coolant fluid place in the furnace does not have a specular surface symmetric face, a prescribed shape is given, and an unstable fluid area is curtailed. As a result, the entrainment of cover gas caused by the generation of an unstable eddy and an unstable free liquid level oscillation can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Industrial Field of Application) The present invention relates to fast breeder reactors, and particularly to the arrangement structure of an intermediate heat exchanger and a main circulation pump in a reactor vessel.

(Prior Art) A conventional tank-type fast breeder reactor will be described with reference to the vertical cross-sectional view of FIG. As shown in the figure, the reactor vessel 1 houses a reactor core 4 supported by a core support machine @9 and a coolant 15, and the upper opening of the reactor vessel 1 is connected to the roof slab 1.
Blocked by 0.

A partition wall 1 is provided between the core support mechanism 9 and the inner periphery of the reactor vessel 1.
2 is provided, and the coolant storage space in the reactor vessel 1 is divided into an upper plenum 5 and a lower plenum 6 by this partition wall 12 . Further, an intermediate heat exchanger 28 and a circulation pump 3 are supported on the roof slab 10. Both the intermediate heat exchanger 2 and the circulation pump 3 pass through the partition wall 12, and the intermediate heat exchanger 2 has a coolant inlet 13 on the upper plenum 5 side and a coolant outlet 1 on the lower plenum 6 side.
It is equipped with 4. The discharge side of the circulation pump 3 is connected to the lower part of the reactor core 4 via a discharge pipe 11. Also,
The top layout of this tank-type nuclear reactor is shown in Figure 3.
Centering around the rotating plug 10a, intermediate heat exchangers 2a, 2
b, 2c, 2d and main circulation pumps 3a, 3b.

3C and 3d are arranged in mirror symmetry (90' symmetry in this example).

(Problem to be solved by the invention) By the way, in order to rationalize the reactor structure of a tank-type fast breeder reactor, it is necessary to make the reactor vessel more compact, but one of the important issues in this case is to This is stabilization of coolant flow.

In other words, as the reactor vessel becomes more compact, the coolant flow rate inside the reactor becomes relatively faster when the coolant flow rate is kept constant, but if there is an area where the coolant flow is unstable,
There is a possibility that the cover gas will be drawn into the furnace or that it will become a factor in the flow force imaging of the equipment in the furnace. In particular, the former case of entrainment of cover gas is caused when this gas is transported to the reactor core.
It is important to reduce the amount of cover gas entrained as much as possible since it has a significant nuclear and thermal effect on the reactor core.

When looking at the conventional arrangement of equipment in the reactor from this perspective (see Figure 3), the arrangement is mirror symmetrical as described above, so in principle the flow of coolant in the reactor is mirror symmetrical. This should create a flow situation. However, in reality, there are various disturbances, including disturbance factors inherent in the flow itself, so that an unstable region of the flow occurs in the so-called plane of geometrical symmetry shown by diagonal lines in FIG. The entrainment of the cover gas due to the unstable temperature that occurs near the unstable region of the flow was considered to be one of the important issues, especially when aiming to make the reactor vessel more compact.

The present invention has been made to solve the above-mentioned drawbacks.
The purpose is to provide a safe and reliable tank-type fast breeder reactor by reducing the unstable region of coolant flow within the reactor.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a reactor vessel that houses a coolant and has an upper opening closed with a roof slab, and a reactor vessel that contains a coolant and has an upper opening closed with a roof slab. a reactor core provided therein, a plurality of intermediate heat exchangers provided through the roof slab, a partition wall that partitions a coolant storage space in the reactor vessel into an upper plenum and a lower plenum, and the roof slab. A tank-type fast breeder reactor comprising a discharge pipe provided through the reactor, and a plurality of main circulation pumps that feed primary coolant into the reactor core via the discharge pipe, wherein the plurality of intermediate heat exchangers and the plurality of intermediate heat exchangers are provided. The main circulation pump is arranged in the reactor vessel so as to be rotationally symmetrical in the circumferential direction.

(Function) In the present invention, by making the intermediate heat exchanger and the main circulation pump arranged in the furnace rotationally symmetrical, the coolant flow field in the furnace takes on one fixed shape, and cooling as usual Since unstable regions of the material are eliminated, entrainment of cover gas does not occur.

(Example) Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic plan view of an embodiment of the present invention.

As shown in the figure, there is a rotating plug 16 inside the reactor vessel 1.
A plurality of intermediate heat exchangers 2a to 2d (four in the figure) centering on
are mirror-symmetrically arranged as in the conventional case. This is because when considering the arrangement of the secondary system piping of the intermediate heat exchangers 2a to 2d in the upper part of the furnace, a symmetrical arrangement is preferable in terms of the overall layout.

A plurality of (four in the figure) main circulation pumps 3a to 3d are provided, two each on both sides of the intermediate heat exchangers 2b and 2d. Main circulation pumps 3b and 3C are arranged on both sides of exchanger 2b.

As a result, the arrangement of the intermediate heat exchangers 2a to 2d and the main circulation pumps 3a to 3d in the furnace is 180° rotationally symmetrical.

Since this embodiment has the above-mentioned configuration, the coolant flow field in the reactor does not have a plane of mirror symmetry, so it is given a certain fixed shape, and unstable flow distortion is reduced. . As a result, entrainment of the cover gas and unstable free liquid level fluctuations due to generation of unstable vortices can be reduced.

[Effects of the Invention] As explained above, according to the present invention, there is no unstable flow region of coolant, so entrainment of cover gas is eliminated, and a safe and highly reliable tank-type fast breeder reactor is provided. can do.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view of an embodiment of the present invention, Fig. 2 is a vertical cross-sectional view of a conventional tank-type fast breeder reactor, Fig. 3 is a schematic plan view of Fig. 2, and Fig. 4 is a conventional fast breeder reactor. This is a diagram for explaining an unstable region of coolant flow in a breeder reactor. 1...Reactor vessel 2.2a-2d...Intermediate heat exchanger 3.3a-3d...Main circulation pump 4...Reactor core 5...Upper plenum 6...Lower plenum 7... - Upper reactor mechanism 8... Fuel exchanger 9... Core support mechanism 10... Roof slab 11... Discharge pipe 12... Partition wall 13... Inlet 14... Outlet 15...・Coolant 16... Rotating plug agent Patent attorney Nori Ken Chika Yudo Ken Daishimaru Figure 1 Figure 2 2d Figure 8 d Figure 4

Claims (1)

[Claims] (1) A reactor vessel containing coolant and having an upper opening closed with a roof slab, a core provided within the reactor vessel, and a plurality of intermediate heat exchangers provided penetrating the roof slab. a partition wall that divides a coolant storage space within the reactor vessel into an upper plenum and a lower plenum; a discharge pipe provided through the roof slab; and a primary cooling supply to the reactor core via the discharge pipe. In a tank-type fast breeder reactor equipped with a plurality of main circulation pumps for feeding materials, the plurality of intermediate heat exchangers and the plurality of main circulation pumps are arranged in the reactor vessel so as to be rotationally symmetrical in the circumferential direction. A tank-type fast breeder reactor characterized by being located in.