JPS59168389A - Thermal shield structure of reactor container wall - 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 heat insulating layer@, and particularly to a heat insulating structure suitable for use in liquid metal cooled fast breeder reactors and the like.

An example of a conventional heat insulating structure is shown in FIG.

In FIG. 1, between the hot plenum l and the reactor vessel wall 4 there is a cooling layer 3 through which a coolant flows and a gas insulation layer 2. If the coolant flow rate is sufficient, the temperature of the furnace vessel wall can be maintained at a low temperature due to the heat insulation effect (2) and the cooling effect (3). Further, even if the amount of coolant a cannot be obtained, the temperature rise in the wall of the furnace vessel can be made slow due to the heat insulation effect in 2 and the heat capacity effect of the coolant in 3. Incidentally, in order to absorb thermal expansion, it is advantageous for the gas heat insulating layer to have its upper part opened into the cover gas in terms of structural integrity. In such a heat insulating structure, when coolant flows into the scum heat insulating layer as shown in Figure 2 due to fluctuations in the hot blemish liquid level or the wall cooling layer liquid level, the gas layer is filled with coolant and the heat insulation layer is insulated. lose functionality.

Therefore, the conventional heat insulating structure has the disadvantage that it is not possible to maintain a low flow through the wall of the furnace vessel.

An object of the present invention is to provide a highly reliable and suitable heat insulating structure for a reactor vessel of a fast breeder reactor, etc., which compensates for the drawbacks of the conventional gas heat insulating layer as described above.

The present invention has a gas insulation layer having multiple air pockets as shown in 5 in FIG.

With such a structure, as shown in FIG. 4, even when coolant flows into the gas insulation layer, gas remains in the air pocket and the insulation function can be maintained. Furthermore, even if the airtightness of one air pocket is lost, the insulation function can be maintained by the gas layer of the other air pocket.

That is, the present invention can be said to be a gas insulation structure that guarantees sound insulation function over various events.

FIG. 5 shows an example in which the present invention is implemented in a tank-type fast breeder reactor.

In FIG. 5, sodium heated to a high temperature in the reactor core 6 enters the hot plenum 1. Furthermore, it enters the intermediate heat exchanger 7, exchanges heat with the secondary side sodium, becomes low temperature, and enters the cold plenum 8. After being pressurized by the pump 9, it passes through the high-pressure plenum 10 and enters the core 6 again.

The temperature of sodium in the hot plenum above is 5ooC
If special consideration is not taken, the upper half of the reactor vessel 4 will reach a high temperature of around SOOC, which is not desirable in terms of structural strength. For this reason, in order to thermally isolate the walls of the hot plenum 1 and the reactor vessel 4, a gas insulation layer 2'ft having multiple air pockets is provided. If the temperature of the reactor vessel wall cannot be kept low with only the gas insulation layer, a cooling layer 3 may be provided as a backup.

Incidentally, in such a nuclear reactor, the liquid level in the hot plenum may fluctuate due to an abnormal event such as an earthquake. As mentioned above, by providing multi-layered air pockets 5 in the gas insulation layer, even if sodium from the hot plenum flows into the gas layer due to liquid level fluctuations, the gas pressure inside the pockets will keep the sodium from flowing. , cannot flow into the pocket. The insulation function is therefore protected by the gas layer inside the pocket.

Furthermore, by multiplexing these gas pockets, even if one air pocket is damaged, the remaining gas layer will maintain the insulation function.

Furthermore, the manufacturing technology of the present heat-insulating structure is similar to the manufacturing technology of conventional manometer seals, and has the advantage of providing a highly reliable heat-insulating structure without significantly increasing manufacturing costs.

According to the present invention, even in an abnormal event such as when coolant flows into the gas insulation layer, the insulation function can be maintained, so in a nuclear reactor, etc., the reactor vessel is always kept at a low temperature. Can fully meet strength requirements.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a conventional heat insulating structure with a gas layer, Figure 2
The figure is an explanatory diagram when a coolant flows into the gas layer, FIG. 3 is an explanatory diagram of an insulating structure having a gas layer with multilayer air pockets according to an embodiment of the present invention, and FIG. 4 is an explanatory diagram of the gas layer as well. Ta'
FIG. 5, which is an explanatory diagram when sodium flows in, is an overall diagram showing an example of application of the present invention to a fast breeder reactor. 1...Hot plenum, 2...Gas insulation layer, 3...
・Cooling layer, 4...Furnace vessel, 5...Air pocket, 6
...Reactor core, 7...Intermediate heat exchanger, 8...Cold pre-cum, 9...Mine 1, Figure 2, Figure 3, 1,000,41 yen

Claims (1)

[Claims] 1. The upper part is opened into the furnace vessel cover gas, the side part, and
1. A furnace wall insulation structure having a gas insulation layer with a closed bottom, characterized in that the gas insulation layer is provided with multilayer air pockets.