JPH02720Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an improvement in an exhaust duct system for radiation shielding in facilities such as hot cells that handle high levels of radioactive materials.

In facilities such as hot cells that handle high-level radioactive materials, the exhaust duct for the room has traditionally been a single, large-diameter exhaust duct that penetrates walls or floors that require high radiation shielding performance. ing.

That is, FIG. 1 shows the configuration of an exhaust duct system in a facility such as a conventional hot cell.
In the figure, 1 is a hot cell, 2 is a shielding wall, 3 is a shielding floor,
Reference numeral 4 indicates a filter box installed in the hot cell 1, 5 a filter, 6 a duct, and 7 a shielding compensator for radiation transmitted through the duct 6. In this configuration, Regarding radiation shielding, when radiation is attenuated by scattering within the duct, in order to prevent it from leaking to the outside, it is necessary to provide a considerable number of bends in the buried part of the duct and to make it considerably long. This causes a large damage to the shielding wall or floor, and as a countermeasure, the shielding wall or floor must be made considerably larger in size.

In addition, it is necessary to bury plates such as iron plates in various places around the bends of the duct in order to compensate for the shielding of radiation that passes through the bends, but the presence of such complicated buried objects may cause structural defects in the frame. become.

This proposal was made in view of the above circumstances, and its gist is that the exhaust ducts buried through the radiation shielding wall or floor are made into multiple smaller-diameter exhaust ducts, and the shielding wall or floor is A duct chamber shall be provided in contact with the duct chamber, and the above-mentioned exhaust duct group shall be connected to this chamber, and within the chamber, in front of the duct hole, in a direction parallel to the shielding wall surface, and at a distance to the extent that air circulation is not obstructed. By arranging a radiation shield and connecting or integrating such a chamber with the filter box, it is possible to reduce the design dimensions of the shielding wall or floor without compromising the radiation shielding ability and to prevent intrusion into the duct. The aim is to eliminate structural defects in the building frame by eliminating the need for shielding and compensating buried objects by reducing the bending of the duct due to the effect of reducing the width of radiation.

Details of this will be explained below based on embodiment figures.

FIG. 2 is a perspective view with one side of the filter box omitted, showing that the in-self filter box 9 with the filters 8, . . . It is installed on this basis on the shield casing 10.

The other side of the shield casing 10 is a duct chamber, which ensures a predetermined exhaust throughput and is rational for shielding (the shielding effect against scattering within the duct and radiation leaking due to this scattering depends on the diameter of the duct). ) The buried duct 11 is configured to have a smaller diameter at the point where the diameter is smaller and is configured into a plurality of ducts.
A radiation shield 12 is installed near the opening of the duct 11, so as to cover the duct 11 with a distance that ensures air circulation.

Incidentally, FIG. 3 shows a longitudinal sectional view of the duct in which the air flow is indicated by arrows.

Therefore, since the present proposal has the above-mentioned configuration, by directly connecting a plurality of ducts with reduced diameters to a box-shaped duct chamber that is in contact with one or more sides of the wall or floor in which the ducts are buried, it is possible to It is possible to streamline the size of the shielding wall or floor while maintaining its shielding ability, and it is also possible to install a plate made of a material effective in radiation shielding, such as a steel plate or a lead plate, in front of the duct hole opened in the chamber. By arranging the ducts at a distance that does not obstruct air circulation, the amount of radiation that enters the duct hole is greatly reduced, so the number of bends in the buried duct can be reduced without causing structural defects in the building frame. On the other hand, by integrating or connecting the chamber with a conventional filter box, it can also serve as the foundation of the filter box, making it rational in terms of earthquake resistance. , the layout of cells, etc. is also reasonable.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a conventional exhaust duct, FIG. 2 is a perspective view of the device of the present invention, and FIG. 3 is an explanatory diagram of airflow of the device of the present invention. 8... Filter, 9... In-cell filter box, 10... Shield casing, 11... Buried duct, 12... Radiation shield.

Claims (1)

[Scope of utility model registration request] The exhaust ducts buried through the radiation shielding wall or floor are made into a plurality of smaller diameter exhaust ducts to form an exhaust duct group, and a duct chamber is provided in contact with the shielding wall or floor, to which the exhaust duct group is connected, Within the chamber, a radiation shield is placed in front of the duct hole in a direction parallel to the shielding wall surface and at a distance that does not obstruct air circulation, and such a chamber is connected to or integrated with the filter box. Features: Exhaust duct device for radiation shielding.