JPH0143679Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a container suitable for intra-plant transportation of solid waste contaminated with powdered alpha emitters, particularly plutonium.

Traditionally, solid waste such as valves, glove boxes, and filters contaminated with alpha emitters, such as plutonium, have been placed in polyvinyl chloride bags, sealed, and then placed in storage containers due to the strict packaging requirements. It was stored in storage rooms or warehouses.

However, in recent years, as national policy has advanced the development of peaceful uses of nuclear energy, especially the effective use of plutonium, the amount of solid waste such as valves and filters contaminated with particulate alpha emitters such as plutonium has increased. storage capacity is reaching its limits.

Therefore, there is a growing momentum to install volume reduction treatment facilities for these solid wastes on the premises of facilities that handle alpha emitters, and there is an urgent need to manufacture containers to transport solid waste from storage rooms or warehouses to processing facilities. It's becoming a problem.

However, when such solid waste is transported on-site, the detailed technical standards regarding transport containers from the perspective of laws and regulations are not as strict as those for off-site transport containers. In addition, since the transported object is contaminated with alpha emitters, there is no particular problem with heat dissipation performance or shielding performance, and as long as it is for transportation within the premises, it will be finely powdered under the impact of a fall of 1 to 2 meters. It is considered that it is sufficient to have sufficient sealing performance against α emitters. However, in the case of solid waste contaminated with plutonium, it has not been possible to design containers with sufficient sealing performance that can be supplied economically in large quantities while complying with legal allowable leakage standards. This is an extremely difficult technical problem.

For this reason, there is currently a demand for containers that are sufficiently economical while satisfying legal regulations.

Therefore, the present invention has been developed in view of the current situation, and maintains a sealing performance sufficient for the purpose of intra-plant transportation, and almost completely prevents leakage of fine powdered alpha emitters. In addition, it is possible to maintain an even air pressure difference inside and outside the container, which is the driving force for leakage, and it can withstand drops of 1 to 2 meters, making it suitable not only for on-site transport containers but also for storage containers. It has the advantage that it can also be used.

In other words, the container for on-site transportation of α-contaminated solid waste according to the present invention is composed of a lid and a main body, each having reinforcing ribs formed on the outer surface thereof, and has an opening formed in the lid and/or the main body for transporting fine particles. A filter for collecting alpha emitters of the shape of the shape is attached, filter protection plates are provided on both sides of the filter in a removable manner, and a sealing material is interposed between the lid part and the main body part and at the attachment part of the filter. It is characterized by this.

The present invention will be described below based on embodiments shown in the drawings.

Figure 1 is a plan view of the container according to the present invention, Figure 2 is a plan view of the container according to the present invention;
The figure is a sectional view of the container 1, and the container 1 is composed of a lid 2 and a main body 3.
A reinforcing rib 4 is formed on each outer surface side.

Furthermore, an opening 5 is formed in the main body 3.
A filter 6 for collecting fine particles of α emitters is attached to this opening 5 . As shown in FIG. 2, the opening 5 may be formed not only in the main body 3 but also in the lid 2, or in both the lid 2 and the main body 3. . The lid part 2 and the main body part 3 are formed of a carbon steel plate or a corrosion-resistant high-strength aluminum plate with an inner surface lined with stainless steel, and in any case, it is preferable that the inner surface be buffed or otherwise polished to a mirror surface. As an example of the filter 6, a normal α
Like the filters in half-face masks to prevent internal radiation exposure used in facilities that handle radiators,
Particle collection efficiency is 99.97% by 0.3μDOP test
A material that has high particle collection efficiency as described above and whose performance does not deteriorate even under impact of 1 to 2 meters is used.

The DOP test, or dioctyl phthalate test, measures the collection efficiency with 0.3 micron DOP smoke, and is currently the most rigorous test method adopted by the U.S. Atomic Energy Commission. Therefore, in Japan as well, almost all nuclear power spec filters are used that have passed this test.

Further, in the present invention, filter protection plates 7 and 7' are provided on both the inside and outside of the filter 6, respectively, to prevent the filter from being damaged when the container falls or due to local external force. Specifically, for example, as shown in the enlarged view of the main part in FIG. 3, the filter 6 is fixed to the main body 3 from the outside A with a filter fixing plate 8, and a filter protection plate 7' is attached to the filter fixing plate 8. On the other hand, on the inside B, a filter protection plate 7 is directly attached to the main body part 3.

Further, in the present invention, the flange portion 9 of the lid portion 2, the main body portion 3, and the attachment portion of the filter 6 are each sealed by a sealing member 10 such as a rubber O-ring.

The sealing performance of the container of the present invention is such that the pressure difference between the inside and outside of the container, which is unavoidable due to atmospheric pressure fluctuations under normal usage conditions, is permanently reduced to zero, and air leakage from the sealed parts sealed with sealing materials is almost zero. This is important in preventing particles containing α emitters from leaking out of the container.

This means that even if the same flow driving force of △P is applied, the pressure loss of the filter is negligibly small compared to the pressure loss of the sealed part sealed by the sealing material of each part, so the flow is less than the pressure loss. It utilizes the principle that this occurs through a filter that is so small that it can be ignored. The air inside the container passes through a filter to the outside, but fine particles containing alpha emitters contained in the air are collected by a filter with high collection efficiency and do not escape.

Therefore, before a container is used, its airtightness is usually tested in advance, and an airtightness test is conducted to ensure that the pressure loss from the sealed parts of each part of the container is extremely large. . At this time, the outer filter protection plate 7'
After removing the hole and making it blind, check the air tightness through hole 1.
3 into the container 1, pressurize it to the design pressure of the container, perform an airtightness test similar to a soap bubble test, and confirm that there is no leakage of, for example, 10 ^-2 acc/sec. The pre-leakage inspection is extremely simple and allows transportation in a short time compared to conventional inspections.

In addition, conventional methods such as helium leak tests have been used, and the testing equipment is high-grade and the judgments are professional.
It was also complicated.

During transportation, if the blind plate of the opening 5 is removed after reducing the pressure for airtightness inspection and the pressure inside the container is balanced with atmospheric pressure, airtightness sufficient for transportation can be maintained. . This is because, although air enters and exits through the filter 6, fine particles containing alpha emitters suspended in the air from the solid waste contaminated with alpha emitters inside the container 1 form a primary sealed boundary. This is because even if the polyvinyl chloride bag is torn, it will be collected by the filter 6 and will not leak from the container 1.

When transporting solid waste contaminated with alpha emitters within the premises using the container of the present invention, the solid waste 12 is placed in a polyvinyl chloride bag and sealed, as shown in FIG. After forming a sealed boundary, it is only necessary to put it into the container 1 of the present invention and seal the lid part 2 and the main body part 3 via the sealing material 10, and the airtightness test is easy, so it is suitable for mass transportation. It can be used for the purpose of on-site transportation.

If the container itself cannot absorb enough impact energy, or if the business is required to attach cushioning material, additional cushioning material can be attached to the outside of the container for transportation.

As described above, according to the present invention, since filter protection plates are provided on the inside and outside of the filter, solid waste contaminated with alpha emitters is transported from the storage room or warehouse to the volume reduction facility on the premises. In doing so, the filter is not damaged, and therefore leakage of particles containing α emitters to the outside of the container can be economically and almost completely prevented.

On the other hand, the lid part and the main body part are each provided with reinforcing ribs, and the filter can also withstand the impact of dropping from 1 to 2 meters, so sufficient sealing performance is maintained against leakage of fine particles including α emitters. Suitable for use as a container for on-site transportation where fire resistance is not required.

Furthermore, the container of the present invention can be used not only for intra-plant transportation, but also as a storage container.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is an enlarged sectional view of the main part thereof. 2... Lid part, 3... Main body part, 4... Reinforcement rib,
5...Aperture, 6...α emitter collection filter,
7...Filter protection plate, 10...Sealing material, 12...
...Solid waste contaminated with alpha emitters.

Claims (1)

[Scope of utility model registration request] It consists of a lid part and a main body part each having reinforcing ribs formed on the outer surface thereof, and a filter for collecting alpha emitters in the form of fine particles is attached to the opening formed in the lid part and/or the main body part, and a filter for collecting α emitters in the form of fine particles is attached to the opening formed in the lid part and/or the main body part. A container for intra-plant transportation of α-contaminated solid waste, characterized in that a filter protection plate is provided in a detachable manner, and a sealing material is interposed between the lid part and the main body part and at the attachment part of the filter.