Gamma radiation shielding

ZnBr2 is used as a rayon-finishing agent, as a catalyst, as a gamma-radiation shield in nuclear reactor viewing windows, and as an absorbent in humidity... 

The outside of the pressure vessel is covered by a layer of thermal insulation consisting of a stainless steel wool which is held in place by stainless steel bands and wire mesh. A dead air space separates the steel wool from the inner smface of the cavity steel cylinder, approximately 81 feet (2.6 meters) in diameter and made of 3/4-inch (1.9 centimeters) thick plate, which constitutes the inner boundary of the cell. Lead bricks are stacked against the outside of the cylinder to provide a gamma-radiation shield. Shield cooling coils made of copper tubing are fastened to the steel cylinder beneath the lead. 

Radiation-Density Gauges Gamma radiation may be used to measure the density of material inside a pipe or process vessel. The equipment is basically the same as for level measurement, except that here the pipe or vessel must be filled over the effective, irradiated sample volume. The source is mounted on one side of the pipe or vessel and the detector on the other side with appropriate safety radiation shielding surrounding the installation. Cesium 137 is used as the radi-... 

For example, a 1 MeV point isotropic source of gamma-radiation has a buildup factor ol 2.1 when penetrating a mean-free thickness of water. If the build-up factor is ignored, equation 8.3-11 is exp(-l) = 0.36. Hence, 36% of the radiation passes through the shield. But when the buildup factor is included, 2.1 0.36 = 76% of the radiation penetrates the shield. 

Conductive composites are obtained when powdered metal fillers or metal-plated fillers are added to resins. These composites nave been used to produce forming tools for the aircraft industry. Powdered lead-filled polyolefin composites have been used as shields for neutron and gamma radiation, and metal-filled plastics have been used to prevent interference from stray electrons (EMI). 

The contamination due to 232U in the recovered 233U product leads to intense gamma radiation, which requires specially designed shielded facilities during fuel reprocessing and fuel fabrication. 

Gamma radiation Extremely dangerous penetrating radiation emitted when a radioactive nucleus of an atom decomposes. It penetrates paper, metals and bricks and can only be stopped by a block of lead shielding. It is similar to X rays. 

Figure 7. The attenuation of dose rate of gamma-radiation (1) and neutrons (2) by the concrete shielding.

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