JPH02136789A - Outflow preventive wall for reactor core melt - Google Patents

Abstract

PURPOSE:To avoid a direct contact with a nuclear reactor container caused by a reactor core melt under a severe accident, and to prevent the damage in a short time by providing an outflow preventive wall on reinforced concrete of the bottom part of a dry well. CONSTITUTION:The outflow preventive wall 12 is made of concrete or refractory brick, etc., and its lower part is allowed to adhere closely to reinforced concrete 7 of the bottom part in a dry well. Therefore, a reactor core melt is accumulated between a reactor pressure vessel pedestal 8 and the outflow preventive wall 12, a direct contact with a reactor container caused by the reactor core melt is avoided and the damage in a short time is prevented. In such a way, under a severe accident, the direct contact with the reactor container caused by the reactor core melt is avoided, and the damage in a short time can be prevented.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a nuclear reactor containment vessel, and in particular, to a method for preventing damage to the reactor containment vessel due to direct contact with molten material in a severe accident assuming a core meltdown. Regarding the structure to prevent.

[Conventional technology]

Figure 3 shows a vertical cross section of the conventional Mark 1 reactor containment vessel, which is used as this type of reactor containment vessel. 1 is the reactor pressure vessel, 2 is the reactor containment dry well shell, and 3 is the suppression vessel. Chamber torus shell, 4 is a vent pipe, and 5 is pool water.

Inside the reactor containment vessel dry well shell 2, a dry well inner bottom reinforced concrete part 7 is provided, and the reactor pressure vessel 1 and the reactor shielding wall 9 are fixed by a reactor pressure vessel pedestal 8 that is integrated with this. has been done. , 6 is the outside reinforced concrete part of the dry well, 10
is the reactor containment vessel shield wall.

The reactor pressure vessel pedestal 8 is provided with an opening 11 for maintenance and inspection work at the lower part of the reactor pressure vessel 1, and serves to connect the inside of the reactor pressure vessel pedestal 8 with the outside space. is fulfilled.

[Problem to be solved by the invention]

Marks as shown in Figure 2 - In the reactor containment vessel, after core melt has accumulated in the internal space of the reactor pressure vessel pedestal 8 under a severe accident assuming a core meltdown, the opening 11
It is conceivable that the liquid may flow through the dry well to the inner bottom reinforced concrete part 7 and further reach the reactor containment vessel dry well shell 2. If the core molten material reaches the reactor containment vessel dry well shell 2 in this way, it is possible that the reactor containment vessel will be damaged.

An object of the present invention is to provide an outflow prevention wall that prevents direct contact with the reactor containment vessel by molten material in the event of a severe accident assuming a core meltdown, and prevents damage in a short period of time.

[Means to solve the problem]

The above object is achieved by providing a core melt outflow prevention wall in the reinforced concrete at the bottom of the drywell to prevent core melt from reaching the reactor containment vessel.

[Effect]

The core melt outflow prevention wall is made of concrete or firebrick, and its lower part is tightly attached to the reinforced concrete at the bottom of the drywell. As a result, the core i8F
! Item A is accumulated between the reactor pressure vessel pedestal and the core molten material outflow prevention wall, and damage to the reactor containment vessel is prevented in a short period of time by avoiding direct contact with the reactor containment vessel by the core molten material.

〔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 containment vessel.

The core melt outflow prevention wall 12 is formed of reinforced concrete, and is installed in the reinforced concrete bottom of the dry well outside the reactor pressure vessel pedestal 8 so as to surround the reactor pressure vessel pedestal 8. The core molten material outflow prevention wall 12 is anchored to the drywell inner bottom reinforced concrete 7 at its base, has the strength to accumulate core molten material, avoids direct contact with the core molten material in the reactor containment vessel, and can be used for a short period of time. to prevent damage.

〔Effect of the invention〕

According to the present invention, in a severe accident assuming a core meltdown, direct contact with the reactor containment vessel l by molten core material is avoided, thereby preventing damage in a short period of time.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a reactor containment vessel according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a conventional Mark I reactor containment vessel. 8... Reactor pressure vessel pedestal, 9... Reactor shielding wall, 10... Reactor containment vessel shield wall, 11...
...Opening, 12. Core melt outflow prevention wall. 10th

Claims (1)

[Scope of Claims] 1. A sealed vessel containing a reactor vessel, a pressure suppression chamber filled with a coolant, one end of which is connected to the sealed vessel, and the other end of which is connected to the coolant in the pressure suppression chamber. A reactor containment vessel including a vent pipe to be immersed, the wall for preventing the outflow of reactor core melt, characterized by being provided on a bottom concrete mat in a dry well.