JPS5855890A - Vessel of fast breeder - 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 for a fast breeder reactor.

In particular, the present invention relates to a nuclear reactor vessel that can reduce the thermal stress applied to the vessel wall≦2.

Fast breeder reactors (in general, liquid power) liquid metals, typified by IJum, are used as the coolant.

As a result, such liquid metal coolant flows through the reactor vessel at a rate of 1llH as shown in FIG. That is, 1 in Figure 1 is a reactor vessel which houses a reactor core 2 therein, and the coolant p that flows in through the inlet nozzle 4 provided on the vessel wall 3 of this reactor vessel is guided into the reactor core 2. After the reactor core 2 is heated up, a free liquid level 5 is formed (7) while the coolant aS in the fast breeder reactor passes through the outlet nozzle 6 provided at the top of the vessel wall 3 (2). During normal operation, the core inlet is 300C to 4ooIIC1. In the reactor shutdown state C, both the inlet and the outlet are maintained at approximately 2000C. At the start of reactor operation, the temperature of the coolant outlet nozzle 6 is 2 As shown in Figure 62, the normal operating temperature T is lower than the stop temperature T1.
The core reaction is controlled so that the temperature rises at a certain rate until It is desirable to make this temperature increase rate as large as possible in terms of plant operation in order to increase efficiency and operation rate.

By the way, in fast breeder reactors, because a corrosive alkali metal liquid is used as a coolant, the reactor vessel is usually made of stainless steel. As is well known, stainless steel has very low two-temperature conductivity. For this reason, as mentioned above, the bond temperature rate is increased at the start of operation.

Corresponding to FIG. 3(a), as shown in FIG. 3(b), each thermal temperature of the container wall 3 is as shown by 8a in the figure,
A large temperature gradient occurs near the liquid surface, and therefore,
Although the temperature increase rate at the start of operation is increased, the above-mentioned thermal stress is reduced by some means.

The present invention has been made in view of the above circumstances, and the seventh object is to easily reduce the thermal stress generated near the liquid level of the H member on the wall of the reactor vessel at the time of starting and stopping the reactor operation. This can be reduced with a suitable configuration, thereby improving safety.

C: To provide a reactor vessel for a fast breeder reactor that can contribute to improving the efficiency of a nuclear reactor plant and L: operation rate.

That is, 1 the present invention provides the side wall outer surface C of the reactor vessel main body:
At least the heat pipes should be installed at least in the circumferential direction so that each of them is oriented almost perpendicular to the liquid level of the coolant, and one end is located above the liquid level and the other end is located near the lower part of the core below the liquid level. Multiple times.

The primary objective was achieved by alleviating the temperature gradient on the container wall, especially near the liquid surface.

Hereinafter, an example of the present invention will be explained with reference to the drawings.

FIG. 4(a) shows the right half cut away from the center line of the furnace vessel according to the present invention, and the same parts as elflN are designated by the same reference numerals 1. However, the explanation of the part that is prosperous will be omitted.

In this embodiment, the side wall portion of the container wall S is outwardly directed C2.

Each is oriented in a direction that substantially intersects with the liquid level 5 of the coolant in the furnace vessel, and the upper end is located near the liquid level above the liquid level 5,
A relationship in which the lower end is located near the lower part of the core 2 below the liquid level 6 (= non-directional heat pipes 9a that utilize the capillary pressure of multiple pipes are fixed at equal intervals in the circumferential direction) It has become.

With such a configuration, at the start of reactor operation, due to the good heat transfer effect of the heat pipes 9a, the heat of the portion of the vessel 5 wall 3 near the lower part of the core 2 is transferred to the heat source. # of coolant in vessel wall 3 through pipe 9 & 1 from direction 5
This will be transmitted to the low-temperature parts of the body. Therefore, due to the presence of the heat pipe 9a, the portion of the container wall 3 located above the liquid 15 receives heat from the side of the container wall, that is, through a sufficiently wide heat supply path. Therefore, even if the containers 11j and s are made of a material with low thermal conductivity, the temperature will rise in a short time,
As a result, the temperature gradient in the above portion can be made sufficiently gentle.

Therefore, at the start of operation of the reactor, the stirring temperature should be lowered to 62° and 11°.
Even if the thermal stress I is increased, the vessel wall will not break, and this will ultimately contribute to improving safety and improving the efficiency and operating rate of the reactor plant. Moreover, the temperature gradient on the container wall near the liquid surface can be alleviated with a simple configuration of adding a heat pipe, and with a means that does not require any power or control, so the overall cost of the equipment can be reduced. There is no risk that the control will become complicated.

In this case, in particular, since the lower part of the heat pipe 9a is located near the lower part of the reactor core 2 on the vessel wall 3, the temperature of the coolant near the liquid level 5.

In other words, without increasing the temperature of the coolant flowing into the intermediate heat exchanger C2, it is possible to raise the temperature of the portion of the container wall 3 above the liquid level 5 and to alleviate the temperature gradient near the liquid level.
The heat generated in the core at the start of operation can also be effectively utilized f2.

That is, by providing the heat pipe 9a in this way, at the start of operation, the liquid level of the coolant on the container wall will be lowered as shown by the solid line Ib in FIG. The temperature gradient near 5 can be relaxed compared to the temperature gradient of temperature distribution 8& in the conventional case.Even when the operation is stopped, the opposite temperature gradient can be relaxed by the heat pipe.

Note that the present invention is not limited to the above-mentioned Example L. That is, in the embodiment described above, the heat pipe 9
A is placed only at one location along the axis C2 perpendicular to the liquid level of the coolant, but for example, as shown in Figure wJ5,
Two types of heat pipes 9a and 9b having different lengths may be distributed and arranged in the axial direction. By installing a plurality of heat pipes in the axial direction as described above, the temperature gradient described above can be further alleviated. Furthermore, the type of heat pipe is not limited.

In the example, a heat pipe that utilizes non-directional capillary pressure is used in order to operate the heat pipe both at the start of operation and at the time of stop, but it is only necessary to relax the temperature gradient at the time of start of operation. Case: Second, an enemy type heat pipe may be used. Furthermore, the shape of the heat pipe,
The size and the number of pieces used are not limited either.

As mentioned above (2) According to the present invention, it is possible to reduce the thermal stress applied to the reactor vessel wall at the time of starting and stopping the operation without using a complicated structure, a control V-stem, or extra power. Therefore, it is possible to provide a reactor vessel for a fast breeder reactor that can contribute to improving safety and improving the operating rate.

[Brief explanation of drawings]

Figure 1 schematically shows the reactor vessel for a fast breeder reactor;
Figure 2 is a diagram showing an example of changes in coolant temperature at the start and shutdown of a nuclear reactor, Figure 3 α) is an enlarged view of Figure 1, and Figure 3 (b) is a diagram showing an example of changes in coolant temperature at the start of operation and at the time of shutdown of a nuclear reactor. Figure 3 (a
FIG. 4) is a partially cutaway side view of a reactor vessel according to an embodiment of the present invention. The same figure (the duck is a diagram for explaining the temperature distribution of the vessel wall in the same embodiment, and FIG. 5 is a longitudinal cross-sectional view of a reactor vessel according to another embodiment of the present invention. 7), 1 b ・・-furnace vessel, 2...furnace IC,-,
, 9... Container wall. Late Applicant Patent Attorney Takehiko Suzue Figure 1 Figure 2 Time Figure 3 (b) Inventor: Hisao Yasunaga, 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki City, Tokyo Shibaura Electric Co., Ltd. Research Institute, Tokyo Shibaura Electric Co., Ltd. Inventor: Tomiya Sasaki, Tokyo Shibaura Electric Co., Ltd., 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki City General Research Institute Co., Ltd. 491-

Claims (1)

[Claims] Circulation path I for liquid metal coolant: A reactor vessel body that is interposed and through which the liquid metal coolant flows with a free liquid level, and a side wall outer surface of the reactor vessel body that has the free liquid level, respectively. In a direction substantially perpendicular to the surface, one end is fixed at a position above the free liquid level, and the other end is fixed at a position below the free liquid level near the lower part of the core, and at least a plurality of them are arranged and fixed in the circumferential direction. A nuclear reactor vessel for a fast breeder reactor, characterized in that it is equipped with a heat pipe.