JPS61231491A - Storage facility for novel fuel of nuclear reactor - 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 (Technical Field to Which the Invention Pertains) The present invention relates to a storage facility for new reactor fuel for a pressurized water reactor, which stores new reactor fuel at intervals.

(Prior art and its problems) New reactor fuel (hereinafter referred to as new fuel) for pressurized water reactors is stored in containers arranged at intervals on racks, and the new fuel is It is kept from becoming critical. The prior art will be described below with reference to the drawings.

FIG. 3 is a partial sectional view of a conventional storage facility for storing new fuel, and FIG. 4 is a sectional view taken along line AA in FIG. In FIGS. 3 and 4, a square rod-shaped new fuel 1 is stored in a can 2, which is a square container with an opening, and an opening 2a of the can 2.
is open.

The rack 7 is constructed by arranging support frames 3 made of shaped steel in a lattice pattern as shown in FIG. They are arranged in such a way that the distance between new fuels to be stored is maintained at a distance P. Therefore, the distance P between the new fuel stored in each can 2 is maintained. This interval P is determined so that the neutron multiplication factor is 1 or less so that the new fuel becomes subcritical even in the event of a flooding accident.

However, there is a trend in nuclear power plants to use high burn-up fuel for the purpose of long-term continuous operation.

In this case, since subcriticality cannot be ensured with the conventional storage interval for fresh fuel in the rack, it is necessary to further increase the interval or to attach a neutron absorber such as boron to the fresh fuel storage interval.

Therefore, there is a problem in that the installation space for the rack increases and the cost of construction equipment increases due to the use of neutron absorbers.

(Object of the Invention) In view of the above-mentioned points, the present invention provides a new reactor fuel storage facility that can store high burnup fuel for pressurized water reactors with a simple structure and at low construction equipment costs. The purpose is to provide

(Summary of the Invention) According to the present invention, in a facility for storing rod-shaped new reactor fuel of a pressurized water reactor in containers arranged at intervals on racks, A lid that seals the opening and a sealant that seals between the lid and the opening surface are provided to make the container watertight! This is achieved by configuring.

(Example of the invention) The present invention will be described in detail below based on the drawings.

FIG. 1 is a partial cross-sectional view of a main part of a nuclear reactor new fuel storage facility according to an embodiment of the present invention. In FIG. 1, the same parts as in the conventional example shown in FIGS. 3 and 4 are given the same reference numerals.

In FIG. 1, a can 2, a shaped steel support frame 3. Storing new fuel using a rack 7 consisting of a stopper 4 made of shaped steel is the same as in the prior art, but in this embodiment, the can 2
A lid 5 is provided to seal the opening 2a. The sealing material 6 interposed between the lid 5 and the opening 1 of the can 2 is made of rubber, for example, nitrile rubber, and is adhered to the lid 5 by baking or the like. Note that the lid 5 can be attached and detached using the handle 5g.

With this structure, the lid 5 and the sealing material 6 can prevent water from entering the can 2 in the event that the rack is flooded with water, that is, in the event of a flooding accident.

Therefore, the new fuel in Can 2 is not exposed to water.
It is possible to suppress an increase in the neutron multiplication factor without increasing the interval at which new fuel is stored compared to conventional methods.

FIG. 2 is a graph showing the state of the neutron multiplication factor at the time of a flooding accident in a conventional example and an embodiment of the present invention when new fuel for a pressurized watercolor light water reactor is stored in a rack. In Figure 2, the vertical axis shows the neutron multiplication factor kaff, and the horizontal axis shows the density of water ρ (!i/e'') in the atmosphere when the rack is exposed to water. It shows the mass of water contained per I's. Also, in Figure 2, &a//
=1 is critical, and ρ=1 indicates that the atmosphere is all water.

The solid curve P in Figure 2 represents the relationship between the neutron multiplication factor and the density of water in the conventional nuclear reactor new fuel storage facility, and the wave curve Q
shows the relationship between the neutron multiplication factor and the density of water in the new reactor fuel storage facility according to the embodiment of the present invention. As can be seen from the figure, the maximum value of the neutron multiplication factor due to the new reactor fuel storage facility according to the embodiment of the present invention is reduced by about 10% or more from the maximum value of the conventional system. Therefore, it is possible to suppress an increase in the storage interval during high burnup fuel storage.

(Effects of the invention) □As is clear from the above explanation, according to the present invention, a lid is provided to seal the opening of a container disposed in a rack for storing new reactor fuel of a pressurized water reactor. By interposing a sealing material between the lid and the opening surface to create a water seal structure and storing new fuel, water can be prevented from entering the container in the event of a flooding accident, and the neutron multiplication factor will not increase. The interval at which new reactor fuel is stored can be reduced compared to conventional containers with open openings, the installation space for storage equipment can be reduced, and there is no need to use neutron absorbers. This has the effect of reducing construction equipment costs.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional view of the main part of a storage facility for new reactor fuel according to an embodiment of the present invention, and Fig. 2 shows the density of water and neutron multiplication factor when new reactor fuel of a pressurized water reactor is stored. FIG. 3 is a partial sectional view of a conventional nuclear reactor new fuel storage facility, and FIG. 4 is a sectional view taken along line AA in FIG. 3. 1: New reactor fuel, 2: Can as a container, 5 = lid,
6: Seal material, 7: Rack 0 Figure 1 Figure 2i! 1

Claims (1)

[Claims] In a storage facility for new reactor fuel for a pressurized water reactor, comprising a container for storing rod-shaped new reactor fuel and a rack for arranging the containers at intervals, a lid for sealing an opening of the container; 1. A nuclear reactor new fuel storage facility, characterized in that the container is configured to be watertight by providing a sealing material for sealing between the lid and the opening surface of the container.