JPS5930479Y2 - Radioactive material storage container - Google Patents

Description

[Detailed description of the invention] This invention relates to a pre-finished radioactive material storage container.

7. Generally, when storing radioactive materials, such as fuel materials, used fuel, or high-level waste, the surrounding area must be covered with concrete (hereinafter referred to as concrete) to shield the radiation emitted from the radioactive materials. for,
It includes not only so-called concrete but also mortar.

) is often covered with

Incidentally, conventionally, such concrete covering has been carried out exclusively by pouring it on-site, but since the substance to be contained is a radioactive substance, several problems cannot be denied in terms of design or construction.

The problems include the following:

■In the case of on-site pouring, it is quite difficult to completely eliminate significant voids.

(2) As radioactive materials undergo atomic decay, the strength of the concrete increases due to the decay heat, which may cause moisture in the concrete to evaporate and reduce the strength of the concrete.

For the same reasons as ① and ②, since the water content in concrete decreases, there is a risk that the shielding ability of concrete, especially against neutrons, will decrease.

(2) In the case of on-site pouring, even if voids are found in the concrete by radiation leakage tests after pouring, repairing them is extremely difficult and may be impossible.

This idea was made in consideration of the above points, and by integrating the shielding concrete itself for shielding radiation with the main body of the container that houses the radioactive material, it can be produced in a factory (i.e. , prefabricated) radioactive material storage container.

Hereinafter, the content of this invention will be explained in detail with reference to the accompanying drawings.

First, to describe the features of this invention, in the radioactive material storage container V of this invention, as shown in FIG. A closed space of a required width is formed between the container outer shell 22, the metal inward flange 2b extending to the upper opening of the container outer shell 22, and the inner peripheral surface and inner bottom surface of the container outer shell 22. 3, and a concrete layer 10 filled in the closed space 3. It is something.

Of course, a shielding lid 4 is provided in the opening 2a of the container inner shell 21 of the container main body portion 2 having a double wall structure so as to be openable and closable.
Although not shown, the inward flange 2b or lower part 2c of the container body portion 2 is provided with an inlet for filling concrete.

However, the most important thing to note here is that the container main body part 2 not only forms a double wall, but also that the container inner shell 21 and the container inner shell 22 form a closed space 3. It is.

Since such a closed space 3 is filled with concrete, various advantages as described below can be obtained.

In this case, the closed space 3 can be formed by the container inner shell 21 and the container inner shell 22 by integrally molding the container main body part 2, but usually, the container inner shell 21 and the container inner shell 22 can be integrally molded.
A method is adopted in which the container shell 22 and the container shell 22 are made separate bodies, and then integrated by welding.

However, in any case, the radioactive material storage container V according to this invention can be produced in a factory, and in that case, the work of filling concrete into the closed space 3 formed by the container body part 2 is also performed one by one. Therefore, quality control is easy, and there is a risk of voids forming inside the concrete.

Furthermore, even if a gap occurs, a radiation leakage test can be performed on each container before it is delivered to the site, so the problematic container can be removed in advance.

Next, we will discuss the case where the above-mentioned container (2) is sent to the site.In this case, since radioactive materials generate decay heat, it is desirable to take measures against this heat.

There are two possible ways to counter this heat: water cooling and air cooling.

Figure 2 shows an example in which water cooling is applied, and as shown in the figure, each container
Wrap the cooling water pipe 5 around each container V, V
, ... are embedded and fixed in the recess 6a of the concrete foundation 6 (of course, the concrete between the containers V, V, ... is cast on site.

Cooling water is circulated through the cooling water pipes 5 of each container V 1 , V 2 , . . . through a cooling water outgoing pipe 7 a and a cooling water returning pipe 7 b.

On the other hand, Figure 3 shows an example in which air cooling is applied;
The bottom part of the container V is opened for exhaust gas, and accordingly, a chamber 8 is provided at the bottom of each container V, V, . . . to collect the exhaust gas.

Here, each container V, V, ... itself is embedded and fixed in the recess 6a of the concrete foundation 6, and the cooling air A is supplied to each container through the air supply port 9a provided in the shielding lid 4. It enters the inside of the main body 2 and then goes to the chamber 8 through the opening 9b at the bottom, after which it is subjected to a cleaning process and is reused for cooling.

In addition, even in the case of such air cooling, although the opening 9b is provided at the bottom of each container (2), the double-walled container inner shell 21 and container outer shell 22 do not form the closed space 3. Of course, it is composed of

As shown in Figures 2 and 3, if a container V is placed in the recess 6a of the concrete foundation 6 and the radioactive material inside the container V is stored, radiation leakage may occur for some reason during storage. Even if something happens, it is possible to take measures against radiation leakage by removing only the container (2) that has caused radiation leakage from the recess 6a and repairing the container (2) or replacing it with another container.

Furthermore, the reason why container V can be replaced and repaired is because container ■ is made into a unit, and being able to take measures against radiation leaks in this way is especially important for hazardous materials such as spent nuclear fuel or high-level waste. It is useful for storing things that need to be kept for many years.

As described above, this invention is a container that is housed in a recess formed in a concrete foundation, and includes a container shell with an open top surface, and a container shell that extends into the top opening of the container shell. an inner container body provided inside the container outer shell with a closed space of a required width between the inward flange and the inner peripheral surface and inner bottom surface of the container outer shell, and integrally continuous with the inward flange at the upper part; Since it is composed of a concrete layer filled in the closed space and a shielding lid that closes the upper opening of the inner body of the container, the radiation shielding concrete itself can be integrated with the container body containing the radioactive material, and therefore The shielding concrete itself can be produced in a factory, and quality control such as reducing the voids inside the concrete can be easily carried out.Also, since the shielding concrete itself is covered with a metal plate, the concrete itself can be You don't have to expect that much strength, and you don't have to worry about dehydration (Murado has an excellent advantage).

Furthermore, with this design, the containers themselves are unitized, so even when a large number of containers are arranged, adjacent containers are independent of each other, making it easy to take measures against thermal stress on the entire concrete foundation. It also has the advantage of easily shortening the construction period.

In addition, if a container is placed in a recess in a concrete foundation and radioactive materials inside the container are stored, even if radiation leaks for some reason during storage, only the container that caused the radiation leak should be removed from the recess. The container can be removed and repaired, or replaced (with another container) to prevent radiation leakage.

Furthermore, the container can be replaced or repaired because it is made into a unit, and the ability to take measures against radiation leaks in this way is particularly useful for hazardous materials such as spent nuclear fuel or high-level waste. It is useful for storing items that need to be stored for many years.

[Brief explanation of the drawing]

FIG. 1 is a front cross-sectional view showing an embodiment of this invention, and FIGS. 2 and 3 are cross-sectional views of the case in which a container according to this invention is placed at a site. DESCRIPTION OF SYMBOLS 1... Radioactive substance, 2... Container body part, 21... Container inner shell, 22... Container outer shell, 2b...・Inward flange, 3...
・Perversion space, 4...shielding lid, 5...
Cooling water piping, 6... Concrete foundation, 6a.
...Concavity, 10...Concrete layer,■
・・・・・・Container based on this idea.

Claims (1)

[Scope of utility model registration request] The container is housed in a recess formed in a concrete foundation, and includes a metal container shell with an open top surface, a metal inward flange extending to the top opening of the container shell, and the container. a metal container inner shell provided inside the container outer shell with a closed space of a required width between the inner peripheral surface and the inner bottom surface of the outer shell and integrally continuous with the inward flange at the upper part; A radioactive material storage container comprising a concrete layer filled in a closed space and a shielding lid that closes the upper opening of the inner shell of the container.