JPS6288992A - Nuclear reactor vessel with wave return - 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 (a) Purpose of the Invention [Field of Industrial Application] This invention relates to the structure of a nuclear reactor vessel, and particularly relates to the construction of a coolant in a reactor vessel having a free liquid level during an earthquake. This relates to a nuclear reactor vessel with a structure to suppress sloshing.

[Prior art] A boiling water reactor (BW) is a nuclear reactor with a free liquid level.
R) and fast breeder reactor (FC3R), especially those with a high specific gravity of the coolant, especially regarding the shaking of the coolant inside the reactor vessel.
Also, since it is difficult for reactor vessels with large diameters,
As an example, liquid metal cold r! The I fast breeder reactor (tank type) will be explained.

Figure 3 shows an example of the reactor structure of a conventional liquid metal cooled fast breeder reactor (tank type), and in the figure, numeral 1 is the reactor vessel. The reactor vessel 1 is suspended by a roof slab 2, and a certain amount of liquid metal sl-lium 3 is stored therein as a primary coolant. Further, inside the reactor vessel, an intermediate heat exchanger 14, a primary cooling system pump 13, and a core upper mechanism 15, which are in-core equipment, are suspended by a roof slab 2. A heat shielding structure 16 is provided on the lower surface of the roof slab 2 to prevent heat loss and keep the roof slab at a low temperature. Reference numeral 17 indicates a reactor core, and the reactor core 17 has a core support structure 18 extending from the vessel wall of the reactor vessel 1 toward the center of the vessel.
Supported by

In a tank type liquid metal cooled W fast breeder reactor, the coolant 3 leaving the reactor core 17 flows out to the upper blennium 9 of the high temperature g1 region forming the free liquid level 5, passes through the intermediate heat exchanger 14, and flows to the lower part of the low temperature region. Flows into Blenheim 8. J3, normally, a reactor wall insulation structure 1o is installed inside the vessel wall 1a of the reactor vessel 1 to reduce heat input from the upper blemish 9.

In a nuclear reactor having such a free liquid level, sloshing occurs in the primary coolant in the reactor vessel during an earthquake. The magnitude of fluctuation of the free liquid level in response to a given seismic input is approximately proportional to the diameter of the container filled with liquid, so in tank-type liquid metal cooled fast breeder reactors with large reactor vessels, measures to prevent fluctuations are required. If not, sloshing wave heights of several meters may occur. If such large sloshing occurs, the rocking pressure will damage the heat shielding structure on the lower surface of the roof slab, the furnace wall insulation structure, and even the reactor equipment such as the intermediate heat exchanger and the primary cooling system pump, resulting in nuclear damage. There is a problem that the soundness of the reactor structure may not be maintained.
A countermeasure was desired.

[Problems to be Solved by the Invention] This invention has been made in view of the above circumstances, and solves the problem of the shaking of the coolant in the reactor vessel during an earthquake, which the conventional technology has. The purpose of the present invention is to provide a reactor vessel that can maintain the integrity of the reactor structure, including internal equipment.

(b) Structure of the Invention [Means for Solving the Problem] Corresponding to this object, the reactor vessel equipped with a wave return according to the present invention provides a reactor vessel wall or The reactor internal structure is arranged inside the reactor vessel along the wall of the reactor vessel, and is provided with a wave return extending in an arc shape toward the inside of the reactor vessel.

Hereinafter, details of the present invention will be explained with reference to the drawings showing one embodiment.

FIG. 1 is a longitudinal sectional view of a nuclear reactor vessel equipped with a wave return according to one embodiment of the present invention, and FIG. 2 is an enlarged view of section A in FIG. 1. Note that the same reference numerals are used to describe parts that have the same configuration as the conventional one.

In the figure, reference numeral 6 indicates a corrugation, and the corrugation 6 is an annular structure made of a material with excellent corrosion resistance, such as stainless steel, forged or molded so that its cross section is arcuate. In the illustrated example, the wave return 6 is provided on the inner liner 10a of the reactor wall insulation structure 10, which is a reactor internal structure, and its installation position is near the free liquid level 5 in the axial direction of the reactor vessel. There is one location above and two locations below near the free liquid level 5. The reason why the wave return 6 is installed near the free liquid level is that the effect of the wave return is greater than when it is installed in other parts, that is, far below the free liquid level. This is not to say that wave return installed in the area is not effective. Furthermore, although the wave return shown in the figure is an annular one that goes around the reactor vessel wall, there is no problem in making it a split type or discontinuous for manufacturing reasons. For example, in the case of a split type, if the wave return installed at the top level is installed discontinuously in the circumferential direction (not shown in the figure), the discontinuous part of the wave return installed one level below will be the wave return installed at the top level. The function as a wave return is fully demonstrated by shifting the position in the circumferential direction and installing the waves alternately so as not to coincide with the discontinuous part of the wave return.

In Fig. 2, the situation of the wave return is exemplified by the arrow in the figure, and the wave return 6 extends in an arc shape toward the inside of the reactor vessel, and its tip Q 6 a is horizontal or not. Alternatively, slightly curving downward is effective in reducing the sloshing wave height 7. The degree of curvature is appropriately selected depending on the reactor vessel diameter.

Note that the installation of the wave return 6 is not limited to the inner liner of the reactor wall insulation structure, but can be installed on the reactor vessel wall or on the reactor internal structure arranged inside the reactor vessel along the reactor vessel wall. Needless to say, it is possible. Even in this case, the wave return effect remains almost unchanged.

U action: The waves in the upper brenum caused by the shaking of the coolant in the reactor vessel during an earthquake are attenuated by the wave return, as illustrated in Figure 2, and the generation of standing waves is suppressed, so the growth of sloshing is suppressed. significantly reduced.

(C) Effects of the Invention According to the present invention, it is simple to provide a flange-shaped return that extends inwardly in the reactor vessel in an arc shape, that is, faces inward as a whole with respect to the reactor vessel. It is possible to obtain a reactor vessel that can suppress sloshing depending on the structure.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a reactor vessel equipped with a wave return according to an embodiment of the present invention, Fig. 2 is an enlarged view of the J3 (△) part in Fig. 1, and Fig. 3 is an enlarged view of the conventional reactor vessel. It is a longitudinal cross-sectional view of a tank-type liquid metal cooled fast breeder reactor. 1... Reactor vessel 1a... Reactor vessel wall 3
...Liquid total bending sodium 5...Free liquid level 6
...Return wave 6a...Tip 7...Sloshing wave height 9...Upper blemish 10...Reactor wall insulation structure 10a...Inner liner Patent applicant Mitsubishi Atomic Crab Industry Co., Ltd. Representative Patent Attorney Kawa Osamu Ii Figure 1

Claims (3)

[Claims] (1) In a reactor vessel having a free liquid level, a circular motion toward the inside of the reactor vessel is applied to the reactor vessel wall or to the reactor internals arranged inside the reactor vessel along the reactor vessel wall. An atomic container equipped with a wave return that is characterized by having a wave return that extends in an arc shape. (2) A reactor vessel equipped with a wave return according to claim 1, wherein the reactor internal structure is an inner liner of a reactor wall insulation structure. (3) A reactor vessel equipped with a wave return according to claim 1 or 2, characterized in that the wave return is provided in a plurality of stages in the axial direction of the reactor vessel (4) The wave return A nuclear reactor vessel equipped with a wave return according to claim 3, wherein the wave return is provided near the free liquid surface above and below the liquid surface.