JPH01109298A - Nuclear reactor vessel - Google Patents

Abstract

PURPOSE:To prevent the local buckling of a nuclear reactor vessel by connecting the supporting structure of the reactor core to the barrel part of the reactor vessel, providing the supporting part of the reactor vessel to the barrel part as well and matching the positions thereof. CONSTITUTION:The core supporting structure 5 is the ribbed structure to support the core 4 and is joined to the reactor vessel 1. A reactor supporting mechanism 16 exists in a cylindrical shape by passing a safe vessel 2 at the same height as the height of the joint part thereof and is joined to a reactor building 12 to support the entire part of the reactor. Seismic load acts over the entire part of the reactor but the load acting on the core 4 is transmitted through the structure 5 to the vessel 1 when an earthquake arises at this time. Since the vessel 1 has the structure 16 in the same position as the joint position of the structure 5, the load transmitted from the structure 5 can be passed to the reactor building 12 without exerting the load on the vessel 1. The local buckling of the vessel 1 is thus prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a nuclear reactor vessel of a fast breeder reactor (hereinafter abbreviated as FBR), and in particular, the present invention relates to a nuclear reactor vessel of a fast breeder reactor (hereinafter abbreviated as FBR), and in particular, the present invention relates to a nuclear reactor vessel of a fast breeder reactor (hereinafter abbreviated as FBR). The present invention relates to a nuclear reactor structure suitable for increasing the buckling strength of a reactor vessel.

[Conventional technology]

The conventional structure will be explained below with reference to FIG. 4, taking the Super Phoenix as an example.

The reactor vessel 1 is a thin-walled vessel with a plate thickness of 50 mm and a diameter of about 20 m, enclosing a sub-reactor coolant 11 and reactor internal structures, and is suspended from a roof slab structure 3 by direct welding. Inside the main vessel, the coolant is divided into an upper hot plenum and a lower cold plenum by a horizontal partition 14. The reactor core 4 is supported by a core support structure 5 installed in a chain at the bottom of the vessel 1 .

The roof slab strength member is constructed with a multi-cell box beam structure to ensure lightweight and high rigidity.
Container 1 and heat exchanger 8. It is equipped with equipment such as a pump, and is installed on the pedestal by the supporting part of the roof slab 3 at the outermost periphery. Roof slabs are lightweight but highly rigid, so they have sufficient strength to withstand earthquakes.

The core 4 is supported by a core support structure 5 made up of more than ten radial ribs. The inner periphery of each rib is connected by welding to a cylindrical container that houses the neutron shield.
The outer periphery is connected by welding to a skirt structure 13 installed on the container chain.

Next, we will discuss the case of an earthquake. During a horizontal earthquake, the entire weight of the reactor vessel is applied to the supporting portion of the roof slab 3.

The weight of the core 4 is transferred via the core support structure 5 to the chains of the vessel 1 and through the vessel to the supports of the roof slab 3 . The weight of the cold plenum is transferred uniformly to the chains of the vessel 1 and through the vessel 1 to the supports of the roof slab 3.

The weight of the hot plenum is first applied to the vertical bulkheads 17 and then transferred to the horizontal bulkheads 14. It then passes through the container 1 to the support of the roof slab 3. Half of the weight of the pump 9 and the heat exchanger 8 is transferred via the horizontal bulkhead 14 to the bulkhead weld and through the vessel 1 to the support of the roof slab 3. The remaining half is transmitted directly to the support of the roof slab 3.

The weight of the roof slab 3 at the top of the furnace The weight of the two-turn plug is:
It is transmitted directly to the support part of the roof slab 3.

Here, in the event of an earthquake, the weight of the reactor core 4, the weight of the cold plenum, the weight of the hot plenum, and half of the weight of the pump 9 and heat exchanger 8 are It is transmitted to the support part.

[Problem that the invention seeks to solve]

- In the conventional structure, in the event of a horizontal earthquake, 70% of the total weight of the reactor is added to the center of the body of the vessel 1 and below, and is transmitted through the body of the vessel 1 to the support part of the roof slab 3, which is the reactor support part. Therefore, the body of the container 1 is subjected to a large shear force, and shear cliff bending is likely to occur. It has low rigidity and low strength against shear cliff bending.

An object of the present invention is to minimize the shear force applied to the vessel body by considering the position of the reactor support.

The purpose is to reduce the possibility of shear buckling, and to increase the shear rigidity of the main vessel body by installing the reactor support section to reinforce the main vessel body, thereby increasing its strength against shear buckling.

[Means for solving problems]

The above purpose is to
A rib-shaped support structure is connected from the core to the body of the reactor vessel as a core support structure to support the reactor core, and a supporting part of the reactor vessel itself is also provided in the body of the vessel. This is achieved by matching the positions of the

[Effect]

When an earthquake occurs in the reactor structure of the present invention, the load acting on the reactor core is first transmitted to the reactor vessel through the core support structure. Since the reactor vessel has a supporting part of the vessel at the same position as the joint of the core support structure, the load transmitted from the reactor core support structure is effectively transferred to the reactor building without putting a burden on the reactor vessel. I can flow completely. Next, we will examine the Na coolant inside the reactor vessel, the internal structures, the attached structures attached to the sub-reactor vessel, the reactor vessel body, and the reactor vessel lid (roof slab, rotating plug). The load acting on the core support structure is transmitted from the reactor vessel lid at the top of the reactor vessel, but these loads are also transmitted mainly from the core support structure position, so they are not effectively transferred to the reactor building. be swept away.

Further, since the reactor vessel lid is lightweight and has a rigid structure, it is possible to transmit the load applied to the upper part of the reactor vessel without affecting the weight.

In this way, since the core support structure and the support portion of the reactor vessel are provided at positions that are effective for transmitting loads that act during an earthquake, high safety against earthquakes can be maintained.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure is a longitudinal cross-sectional view of the reactor main body.

In the figure, 1 is a reactor vessel, 2 is a safety vessel, 3 is a reactor vessel lid, 4 is a reactor core, 5 is a core support structure, 6 is a core upper mechanism, 7 is a control rod drive mechanism, 8 is a heat exchanger, 9 is a circulation pump, 10 is piping, 11 is a coolant, 12 is a reactor building,
14 is a partition wall, and 16 is a reactor vessel support structure.

A reactor vessel 1 and a safety vessel 2 provided outside the reactor vessel 1 are attached to a reactor vessel lid 3. A reactor core 4 is provided within the reactor vessel 1, and the reactor core 4 is attached to the reactor vessel 1 via a core support structure 5. Further, a core upper mechanism 6 is provided passing through the reactor vessel lid 3, and a control rod drive mechanism 7 is provided in the core upper mechanism 6. A control rod drive mechanism 7 inserts and withdraws a control rod (not shown) into the reactor core 4, thereby controlling the output.

Further, a heat exchanger 8 and a circulation pump 9 are provided penetrating the reactor vessel lid 3, and a pipe 10 is provided above the heat exchanger 8 to guide heat to the outside of the reactor vessel 1. 1o, the reactor building 12 side and the heat exchanger 8 side are connected by a flexible structure (not shown) and can move independently of each other.

The reactor core 4 and core support structure 5 are also immersed in a coolant 11, and a heat exchanger 8. The lower portions of the circulation pump 9 and the upper core mechanism 6 are immersed in the coolant 11.

The coolant 11 heated by the heat generated by nuclear fission in the reactor core 4 flows upward in the reactor vessel 1 from the upper surface of the reactor core 4, and flows into the heat exchanger 8 for heat exchange. and,
The coolant 11 whose temperature has become low due to the heat exchange flows out from the lower part of the heat exchanger I8 to the lower part of the reactor vessel 1, and is sent to the lower part of the reactor core 4 by the circulation pump 9.

The reactor vessel 1 is supported by a reactor vessel support structure 16, which supports the entire nuclear reactor.

FIG. 2 is a detailed view of the reactor vessel support structure, and FIG. 3 is a plan view of the support structure.

The core support structure 5 is a rib-shaped structure that supports the reactor core 2 and is joined to the reactor vessel 1. There is a cylindrical reactor support structure 16 that penetrates the safety vessel 2 at the same height as this joint, and is joined to the reactor building 12 to support the entire reactor structure.

Since the present invention is configured as described above, it can exhibit the following effects.

When an earthquake occurs, an earthquake load acts on the entire nuclear reactor, and first, the load acting on the reactor core 4 is transmitted to the reactor vessel 1 via the core support structure 5.

Since the reactor vessel 1 has the reactor vessel support structure i16 at the same position as the joint of the reactor core support structure 5, the load transmitted from the reactor core support structure 5 is not applied to the reactor vessel 1 and is transferred to the reactor building 12. can flow to. Next, the coolant 119M sub-reactor vessel upper cover 3 inside the reactor vessel 1 and the core upper mechanism 6 attached thereto. Heat exchanger8. The loads acting on the attached structures such as the circulation pump 9 and the reactor vessel 1 body are transmitted from the position of the core support structure 5 and the reactor vessel lid 3, but these are also mainly transmitted from the core support structure. Because the load is transmitted, the reactor building 12 is effectively
be swept away.

Further, since the reactor vessel lid 3 is lightweight and has a rigid structure, it is possible to transmit the load applied to the upper part of the reactor vessel without affecting the weight.

In this way, according to this embodiment, the load applied to the reactor body during an earthquake can be effectively transferred to the reactor building 12.

Therefore, shear buckling occurs in the reactor body due to the shear force generated during an earthquake and the length of the fuselage outside the reinforced part, but according to this embodiment, the load acting on the reactor core 4 is Since it flows into the reactor building 12 through the support structure, it is considered that there is no distance from the support point, so buckling hardly occurs. Concerning the loads acting on other parts, the loads are mainly transmitted from the position of the reactor core support structure, so the seismic load is efficiently transferred to the reactor vessel support structure 16 without passing through the body of the reactor vessel 1. , increasing the buckling strength of the reactor vessel. Since the reactor vessel upper structure (roof slab 32 rotating plug 7) has a small weight, even if it is separated from the reactor vessel support structure 16, its influence on buckling is small.

Comparing the ratio of buckling strength between the conventional case and the present invention, we find that in the conventional case, the support point is at the upper end of the reactor body, and the main load related to buckling is on the vessel. Approximately 70% of the total force acts on the body, and the distance from the support point to the point of action is from the upper end to the vessel body, whereas in the case of the present invention, the support point is on the body of the reactor body. The main load related to buckling is reduced to about 30% of the total, and the distance from the support point to the point of action is from the container support to the top. Therefore, in the case of the present invention, the shear force is halved and the reactor vessel body is reinforced, so the buckling strength is more than doubled.

Furthermore, if the core support structure 5 is simply joined to the reactor vessel 1, the load will act on the thin vessel.

Although local buckling occurs, in the present invention, since the positions of the core support structure 5 and the reactor vessel support structure 16, which is a support portion, are aligned, it is possible to prevent the occurrence of local buckling.

〔Effect of the invention〕

According to the present invention, the magnitude of the load acting on the reactor main body and the distance from the point of application of the load to the support point can be reduced, and shear rigidity can be increased, so buckling can be made less likely to occur. Furthermore, local buckling of the reactor vessel can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the nuclear reactor structure according to the present invention, FIG. 2 is a detailed cross-sectional view of the reactor vessel support structure according to the present invention, and FIG. 3 is a plan view of the support structure according to the present invention. Figure 4 is a longitudinal sectional view of a conventional nuclear reactor structure. DESCRIPTION OF SYMBOLS 1... Reactor vessel, 2... Safety vessel, 3... Reactor vessel lid, 4... Reactor core, 5... Core support structure, 6...
... Core upper mechanism, 7... Control rod drive mechanism, 8...
Heat exchanger. Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a reactor vessel housing a reactor core, primary cooling system equipment, etc., the support structure of the reactor core is connected to the body of the reactor vessel, and the support part of the reactor vessel is also connected to the body of the reactor vessel. A nuclear reactor vessel characterized in that it is provided in the body and the positions of both are aligned.