JPS63200098A - Core cooling system - 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 [Field of Industrial Application] The present invention relates to light water nuclear power generation equipment, and particularly to a core cooling system suitable for maintaining flooding of a nuclear reactor core in the event of a loss of coolant accident.

[Conventional technology]

The configuration of a reactor containment vessel of a conventional boiling water nuclear power generation facility and a reactor pressure vessel included therein will be described below with reference to FIG.

Conventionally, a nuclear reactor core 1 is contained in a reactor pressure vessel 2, and the reactor containment vessel 3 is divided into two parts: a dry well 4 in the upper space and a wet well 6 filled with suppression pool water 5 in the lower part. The reactor pressure vessel 2 is located within the drywell.

In the case of a loss of coolant accident, the coolant in the reactor pressure vessel 2 is released into the dry well 4 through the rupture port.

Thereafter, it is guided through the vent pipe 7 into the suppression pool water 5 where it is cooled and condensed. Submergence of the reactor core 1 is maintained by injecting coolant into the reactor pressure vessel 2 by a coolant injection system, but the reactor core 1 is at a higher level than the water surface of the suppression pool water 5, Also,
Since it is surrounded by a large dry well 4 with no coolant, it is necessary to keep the emergency core cooling system (ECCS) pump running and injecting coolant in order to keep the reactor core submerged. there were.

[Problem that the invention seeks to solve]

In the conventional example described above, due to the arrangement of the reactor containment vessel contents equipment, the reactor core is kept submerged by continuing to inject coolant into the reactor pressure vessel, but the surrounding dry well also receives coolant. Providing a large-capacity coolant injection system that fills the air with water is economically problematic.

An object of the present invention is to provide a core cooling system that can fill the lower dry well around the reactor pressure vessel with coolant by taking advantage of the features of natural circulation nuclear power equipment that does not require recirculation piping. .

[Means for solving problems]

The above object is achieved by providing an accumulative water injection system outside the reactor containment vessel of a natural circulation nuclear power generation facility, which secures in advance the amount of water that can fill the lower dry well. Note that this can also be achieved by providing piping and valves that connect the suppression pool and the bottom of the dry well.

[Effect]

Hereinafter, the operation of the present invention for solving the problems in the conventional example will be specifically explained.

The natural circulation nuclear power generation equipment targeted by the present invention is
A lower dry well is provided to form a space in the center of the wet well, and a reactor pressure vessel is installed below this space. Therefore, instead of the reactor pressure vessel being located almost in the center of the large dry well, as in the past, the reactor pressure vessel is bent over the dry well, which is a small space surrounded by a wet well. It has become.

Therefore, if a pressure water injection system with a capacity equivalent to the volume of the lower dry well surrounded by this wet well is installed outside the reactor containment vessel, this pressure water injection system can be activated in the event of a loss of coolant accident. In the short term, this can flood the reactor core, and in the long term, coolant overflowing from the reactor pressure vessel can accumulate at the bottom of the dry well, submerging the reactor pressure vessel. Further, the dry well surrounded by the wet well is small in volume, and the capacity of the pressure water injection system can be reduced.

Furthermore, since the dry well is surrounded by a wet well, the lower dry well is lower than the suppression pool water level, and if piping and valves are installed to connect the suppression pool and the lower dry well, the suppression pool can be easily removed. of coolant can be led to the lower drywell, and the reactor core can be flooded for each reactor pressure vessel.

〔Example〕

The present invention will be explained in detail below.

FIG. 1 shows the structure of a reactor containment vessel and a reactor pressure vessel contained therein in a natural circulation nuclear power generation facility according to the present invention.

A nuclear reactor core 1 is contained in a reactor pressure vessel 2.

This reactor pressure vessel 2 is included in a reactor containment vessel 3. A lower dry well 1o is provided within the reactor containment vessel 3. A pressure suppression chamber consisting of both a wet well 6 and a pool water region 5 surrounds the reactor pressure vessel 2 . A vent passage 14 communicating between the upper dry well 4 in the reactor containment vessel 3 and the pool water region 5 in the pressure suppression chamber is provided in the side wall 13 of the pressure suppression chamber facing the reactor pressure vessel 2 . Below the reactor pressure vessel 2,
A control rod drive device etc. are arranged. The upper dry well 4 and the lower dry well 1o are connected to this space by an annular space formed between the chiron reactor pressure vessel 2 and the side wall 13. In addition, the reactor containment vessel 3 is used as a core cooling system.
A pressure water injection system 8 is arranged outside the reactor pressure vessel 2 and communicates with the reactor pressure vessel 2 via a valve 12 . Piping 9 connecting the suppression pool water area 5 and the lower dry well 10
is also provided. A valve 11 is provided in the pipe 9.

In the core cooling system of the present invention, in the event of a loss of coolant accident, the valve 12
is opened, and the cooling water in the pressure water injection system 8 is injected into the reactor pressure vessel 2. Furthermore, since the coolant overflowing from the reactor pressure vessel 2 flows into the lower dry well 1o, the reactor pressure vessel 2 can be submerged in water.

Furthermore, in the event of a loss of coolant accident, the valve 11 opens and the pool water in the pressure suppression chamber can be guided to the lower dry well 10 by the pipe 9. For this reason, each reactor pressure vessel 2,
The nuclear reactor core 1 can be submerged quickly.

〔Effect of the invention〕

According to the present invention, in a natural circulation nuclear power facility, submergence of the reactor core can be achieved by submerging the reactor pressure vessel, without a dynamic drive source, and core cooling can be performed for a long period of time.

[Brief explanation of the drawing]

Claims (1)

[Claims] 1. A reactor containment vessel includes a wet well and a dry well that contain a suppression pool, and a lower dry well is provided to form a space in the center of the wet well. In light water nuclear power generation equipment in which a reactor pressure vessel is installed, an accumulator water injection system is installed outside the reactor containment vessel, and when a coolant loss accident is short-term, an automatic start signal is sent to the accumulator water injection system to A reactor core cooling system characterized in that when a reactor core is flooded for a long period of time, coolant overflowing from the reactor pressure vessel accumulates in the lower dry well, causing the reactor pressure vessel to be submerged.