JPS6032635Y2 - Spent nuclear fuel storage pool - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a spent nuclear fuel storage pool attached to a nuclear reactor of a nuclear power plant, and particularly to a spent nuclear fuel storage pool suitable for maintaining a constant water level.

Generally, spent nuclear fuel rods in nuclear power plants are
In order to prevent radioactivity leakage and keep it cool, it is stored immersed in water in a spent nuclear fuel storage pool (hereinafter referred to as the fuel pool) for a certain period of time, and then placed in a fuel rod transportation container (hereinafter referred to as a cask) and recycled. It is now being transported to a processing plant.

A conventional fuel pool will be explained below with reference to FIGS. 1 and 2.

In Fig. 1, reference numeral 1 denotes a fuel pool, into which constantly circulating water W is injected up to point P for reasons such as radiation shielding, and in one corner there is a partition wall 2.
A temporary cask pool 3 is provided via the cask.

A cask 4 is temporarily placed in the cask temporary storage pool 3, and spent nuclear fuel rods (not shown) are loaded into the cask 4 from the loading port 5 underwater.

This entrance 5 is provided with a gate 6 that is closed after loading the spent nuclear fuel rods into the cask 4, completely separating the fuel pool 1 and the temporary cask pool 3.

This may cause the cask 4 to be accidentally dropped into the cask temporary storage pool 3 when the cask is being carried in or out.
Even if the floor of the cask is damaged and water leaks, the temporary cask pool 3
This is to prevent the spent nuclear fuel rods in the fuel pool 1 from being exposed to the atmosphere.

In the conventional fuel pool having the above configuration, when the cask 4 is carried in, overflowing water corresponding to the volume of the cask 4 is discharged through the discharge lower, so the cask temporary pool 3
The water level inside does not change.

However, when the cask 4 is carried out, the amount of water in the cask temporary pool 3 is reduced by the volume of the cask 4.

For this reason, the lower wall of the temporary cask pool 3, which has relatively high radiation, is exposed and there is a risk of air pollution.

Furthermore, in order to replenish the water in the temporary cask pool 3, it is necessary for the worker to approach the temporary cask pool 3 and replenish the water using a pump or the like, so there is a risk of the worker being exposed to radiation.

This invention was devised to solve these conventional difficulties, and its purpose is to quantify the amount of water in temporary cask pools and prevent air pollution and radiation exposure of workers. The goal is to provide a spent nuclear fuel storage pool that can be used to store nuclear fuel.

The present invention provides a communication pipe that communicates the two pools with each other at a position below the fuel pool water on the partition wall that separates the fuel pool from the cask temporary pool, and a remotely controllable valve is installed in this communication pipe. After the cask is carried out, the valve is opened to prevent the water level from decreasing in the temporary cask pool.

The present invention will be explained below based on an embodiment shown in FIGS. 3 and 4.

In the figure, 1 is a fuel pool 1, and this fuel pool 1
Because of the need for radiation shielding, etc., the constantly circulating water W is
A cask temporary pool 3 is provided at one corner via a partition wall 2.

A cask 4 is temporarily placed in the cask temporary storage pool 3, and a loading port 5 is provided in the partition wall 2 for loading spent nuclear fuel rods (not shown) into the cask 4 underwater. After the cask 4 is loaded with spent nuclear fuel rods, it is closed by a gate 6, so that the fuel pool 1 and the temporary cask pool 3 are completely separated.

The cask temporary pool 3 has a water level P of the fuel pool 1.
A discharge lower is provided above the point, and is configured to discharge water that overflows when carrying the cask 4 into the cask temporary pool 3 and to maintain a constant water level.

The configuration described above is the same as the conventional one, and in this embodiment, the following configuration is further added.

That is, two communication pipes 8 that connect the fuel pool 1 and the cask temporary pool 3 are provided on the partition wall 2 at positions slightly below the pool water level point R, and each communication pipe 8
is equipped with an electric valve 9 that can be opened and closed by remote control.

By operating the electric valve 9, the fuel pool 1 and the cask temporary pool 3 can be communicated with each other as needed.

Next, the effect will be explained.

When carrying out the cask 4 loaded with spent nuclear fuel rods from the cask temporary storage pool 3, the electric valve 9 is first opened by remote control.

Then, the cask 4 is carried out.

Then, since the fuel pool 1 and the temporary cask pool 3 are completely separated, the water level of the temporary cask pool 3 is lowered by an amount corresponding to the volume of the cask 4 and the spent nuclear fuel rods (not shown).

Water in the fuel pool 1 is then supplied to the cask temporary pool 3 via the communication pipe 8, and a constant water level is always maintained.

This prevents the lower wall of the temporary cask pool 3 from being exposed.

After the water level rises, the electric valve is closed to separate both pools 1 and 3.

As explained above, according to this embodiment, the water level of the temporary cask pool is always maintained constant, there is no risk of air pollution due to exposure of the lower wall, and the electric valve 9 can be operated remotely, so that workers can It is possible to reduce the amount of radiation exposure and the amount of radiation exposure of workers.

In addition, two sets of communication pipes and electric valves are provided, so
Even if one electric valve fails, a sufficient effect can be obtained.

In the above embodiment, two sets of communication pipes and electric valves are provided, but by changing the capacity, one
They may be arranged in sets or three or more sets may be provided.

The present invention has been described above based on the preferred embodiments. According to the present invention, the amount of water in the temporary cask pool can be quantified, and air pollution and radiation exposure of workers can be prevented.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a conventional example, Fig. 2 is a front view of the same, and Fig. 3 is a plan view showing a conventional example.
The figure is a plan view showing an embodiment of the present invention, and FIG. 4 is a front view of the same. 1...fuel pool, 2...partition wall, 3
...Cask temporary storage pool, 4...Cask, 5...Carrying entrance, 6...Gate,
7...Discharge port, butt...Communication pipe, 9...
...Electric valve.

Claims (1)

[Scope of utility model registration request] In a spent fuel storage pool, a cask temporary storage pool separated by a partition wall is installed in one corner of the main body of the pool, and spent nuclear fuel rods are loaded underwater into casks in the cask temporary storage pool and transported out. A spent nuclear fuel storage pool, characterized in that a communication pipe that communicates both pools is provided below the pool water surface of the partition wall, and a remotely controllable electric valve is provided on the communication pipe.