JPS59112283A - Reactor container structure - 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 a reactor vessel structure for a tank-type FB, and more particularly to a reactor vessel structure for a nuclear reactor that reduces the weight of the entire structure and is suitable for earthquake resistance.

A conventional example of FBR will be explained with reference to FIGS. 1 and 2.

A reactor core 1 fixed to a reactor vessel as a heat source of the reactor; an intermediate heat exchanger 4 that exchanges heat between a primary fluid 2 heated to a high temperature in the reactor core and a secondary fluid led to the outside of the reactor vessel 3;
A pump 6 that circulates the low-temperature fluid 5 in the reactor vessel to the reactor core.
, and the furnace vessel 3 containing these are suspended by a roof slab 7 that is the lid of the furnace vessel 3. On the other hand, a control rod (not shown) containing a built-in neutron absorber is inserted into the reactor core 1 and controls the reactor reaction. (not shown)
Now, the core 1 of the nuclear reactor in operation is suspended from the ground.
The reactivity control is performed by adjusting the degree of insertion of the control rods into the reactor core 1. Under normal operating conditions, the necessary vertical control of the control rods is relatively gradual and is easily achieved by the control rod drive. However, during an earthquake, the roof slab 7, which suspends the heavy intermediate heat exchanger 4, pump 6, etc. and has a diameter of 20 m, moves up and down at high frequency, and the amount of displacement is small. If the control rod drive followability is insufficient, the reaction will become unstable, and if more control rods are inserted into the reactor core 1, the reactivity will be controlled, but in the opposite case, the reaction will be accelerated. As a result, in extreme cases, there was a drawback that a rapid criticality state could occur. Another disadvantage is that it is extremely difficult to design a support structure that is strong enough to withstand horizontal motion earthquakes and can absorb the amount of thermal expansion of the entire reactor vessel.

An object of the present invention is to provide a reactor vessel structure that is earthquake resistant and capable of stably controlling the reactor core even against extremely large seismic motions that may occur once during the life of the reactor.

The purpose of the present invention is to keep the vertical movement of control rods within permissible limits by suppressing the deformation of roof slabs as large as 20 m in diameter even in the event of a large earthquake.
The idea is to support the roof slab from the foundation not only on its outer periphery but also on its interior. Also, -
The entire reactor vessel, which is a heavy object that regulates the flow of fluid, is suspended from the roof slab, which suppresses the horizontal movement of the entire reactor vessel during an earthquake, and at the same time reduces the amount of radial thermal deformation of the entire reactor vessel. By using a cross-shaped structure as an absorbable structure, the object is to provide a structure that can support horizontal movement in its perpendicular plane.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. Core 11 fixed to the reactor vessel, intermediate heat exchanger 1
4, the pump 16, and the furnace vessel 13 containing them are suspended by a roof slab 17. On the other hand, control rods (not shown) are suspended from a control rod drive device (not shown) installed on the roof slab 17 and inserted into the reactor core 11. The furnace vessel 13 has a cruciform cross section, and four foundations 18 protrude toward the center of the structure. The pump 16 has a vertical hole 1 provided in the protrusion.
9 and has a structure in which a horizontal hole 20 is provided in the vertical hole 19. On the other hand, the roof slab 17 is attached to the foundation 184. 'It has a structure that can be supported even at the J protrusion.

Now, when vertical earthquake motion acts, the roof slab 17 will move up and down, but since it is supported at the center by the protrusion of the foundation 18 even though its outer diameter is about 20 m, the amount of deformation can be reduced. Since it can be kept small, it is extremely easy to keep it within the allowable value. Therefore, unstable core control such as prompt criticality is not achieved. On the other hand, in response to horizontal earthquake motion, the protrusion of the foundation 18 is used to lift the floor, making allocation extremely easy.

The heat flow as a function of the S-C1 nuclear reactor is basically the same as that of the conventional example (Figure 1), but the heat fluid after heat exchange in the medium+fjl heat exchanger flows through a horizontal hole provided in the foundation. 20(l-
The difference is that it passes through the tube and is sucked into the pump. The pump can also be suspended directly from the base 18, which greatly simplifies the design of the roof slab and reduces its weight.

According to the present invention, the support metal from the foundation of the roof slab can be placed not only at the outer periphery of the roof slab but also at the center, so that the deformation of the roof slab during an earthquake can be minimized. Since the control rods are controlled by Kawaguchi, the vertical movement of the suspended control rods can be kept to a minimum, thereby preventing nuclear runaway caused by unstable changes in core reactivity, such as prompt criticality. Furthermore, since the supporting portions for the roof slab are spread over a wide area, it is thought that the necessary nine performance functions can be ensured even if the rigidity of the roof slab itself is significantly reduced.

In addition, the protrusion of the foundation in the direction perpendicular to the movement acts as a wall against horizontal earthquakes, making it an effective seismic structure.

[Brief explanation of the drawing]

Figure 1 is a conceptual front view of a conventional example;
The figure is a plan view, the third figure is a front view of one embodiment of the present invention, and the fourth figure is a front view of an embodiment of the present invention.
The figure is a plan view corresponding to FIG. 3. 11... Reactor core, 13... Reactor vessel, 17... Roof slab, 18... Foundation, 19... Pit, 20...
・Horizontal hole. Figure 4 Figure 3

Claims (1)

[Claims] ■A reactor vessel containing a reactor core and a core support structure that fixes the core, a pump that circulates thermal fluid through the core, an intermediate heat exchanger that performs heat exchange between the thermal fluids, and a control rod that is inserted into the reactor core. In a nuclear reactor consisting of a roof slab that carries the driving device, the above-mentioned pump, and the intermediate heat exchanger, and suspends the entire reactor vessel, pillars for supporting the roof slab are installed not only around the outer periphery of the roof slab but also at its center. A reactor vessel structure for a nuclear reactor characterized by using.