JPS6259796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in nuclear reactor fuel storage systems for nuclear power plants, such as nuclear power plants.

FIG. 1 is a sectional view of a main part of a conventional nuclear reactor fuel storage device. A fuel pool 2 having a lid 1 at its upper opening contains pool water 3, and a large number of exhaust ports 5 (only one is shown in the figure) provided in a side wall 4 higher than the water surface each have an exhaust duct 6. It is connected to the exhaust duct main pipe 7 through the exhaust duct. In order to prevent mist from forming in the fuel pool 2 due to the evaporation of the pool water 3, making it difficult to take out or put in fuel, an exhaust system with exhaust ports 5 and below is necessary. If pool 2 vibrates, pool water 3
Due to the ripples, the pool water 3 may enter the exhaust port 5, pass through the exhaust duct 6 and the exhaust duct main pipe 7, and be diffused into other rooms.

SUMMARY OF THE INVENTION An object of the present invention is to provide a nuclear reactor fuel storage system that prevents pool water from spreading to other rooms in the event of an earthquake.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

A fuel pool 2 having a lid 1 at its upper opening contains pool water 3, and reactor fuel (not shown) is stored in the water 3. A large number of exhaust ports 5 (only one is shown in the figure) provided on the side wall 4 that is higher than the water level are connected to the exhaust duct main pipe 7 via exhaust ducts 6, but in this case, the exhaust ports 5 are connected to the exhaust duct main pipe 7 from above and below. 8 are provided in a zigzag pattern, and a diffusion suppression tank 10 with a drain pipe 9 provided at the bottom and an isolation valve 11 are provided in series in the exhaust duct 6. This isolation valve 11 is connected to a controller 13 that closes the isolation valve 11 in response to a signal generated by a level detector 12 that detects a ripple surface height of the pool water 3 exceeding a predetermined amount.

Next, the effect will be explained.

When a small amount of pool water flows into the exhaust port 5 due to a small earthquake, the water is led to the diffusion suppression tank 10 through the exhaust duct 6, and air and water are separated by the buttful plate 8 that protrudes in a zigzag pattern from above and below. The water is sent from the drain pipe 9 to a separately provided drain treatment facility (not shown), and only the exhaust gas flows to the exhaust duct main pipe 7, thereby preventing the pool water 3 from spreading from the exhaust duct main pipe 7 to other rooms. can.

On the other hand, in the event of a large earthquake, the level detector 12 detects the height of the ripple surface of the pool water 3 due to the vibration of the fuel pool 2, and the controller 13
By closing the isolation valve 11, pool water that cannot be prevented from flowing out by the diffusion suppression tank 10 is prevented from diffusing from the exhaust duct main pipe 7 to other rooms.

In this embodiment, the reason why the level detector 12 detects the height of the rippled surface is because the rippled water surface is not relative to the exhaust port 5 even if there is a slight change in the level of the pool water when there is no ripples. This is because we want to detect this when it increases by a predetermined amount.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can of course be implemented with various modifications without changing the gist thereof.

As explained above, according to the present invention, water overflowing from the exhaust port due to a small earthquake is prevented from flowing out by the diffusion control tank, and the exhaust gas is exhausted from the main pipe, so there is no need for any maintenance and diffusion control is required. In the event of a major earthquake where the tank cannot prevent the outflow, the isolation valve closes off the outflow, resulting in a reactor fuel storage system that is extremely safe and easy to handle.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the main parts of a conventional nuclear reactor fuel storage system, Fig. 2 is a cross-sectional view of main parts of an embodiment of the nuclear reactor fuel storage system of the present invention, and Fig. 3 is a diffusion suppression tank thereof. FIG. 1...Lid, 2...Fuel pool, 3...Water, 4...
...Side wall, 5...Exhaust port, 6...Exhaust duct, 7...
... Exhaust duct main pipe, 8 ... Boundful plate, 9
...Drain pipe, 10...Diffusion suppression tank, 11...
...Isolation valve, 12...Level detector, 13...Controller.

Claims (1)

[Claims] 1. Reactor fuel is stored in water placed in a fuel pool, the upper opening of the fuel pool is covered, an exhaust port is provided above the water surface on the side wall of the fuel pool, and it is exposed to the outside via an exhaust duct. In a nuclear reactor fuel storage system that is designed to exhaust water, a diffusion suppression tank with a zigzag pattern from above and below, a drain pipe installed at the bottom, and an isolation valve are installed in series with the exhaust duct, and the exhaust duct is connected to a diffusion control tank that is installed in a zigzag manner to prevent pool water from exceeding a predetermined amount. 1. A nuclear reactor fuel storage system comprising: a level detector for detecting the height of a ripple surface; and a controller for closing the isolation valve based on a signal from the detector.