Exposure time, distance, and shielding are the three main factors in keeping radiation levels low wherever radioactive materials are used. In work areas where radiation must come into contact with humans for periods of time that could potentially expose those humans to damaging doses of radiation, such as in nuclear power plants and in medical facilities where x-ray machines are used, radiation shielding is of the utmost importance.
Lead
Lead is possibly the most popular product used in creating radiation shielding. Lead is used to surround the core of a nuclear power plant—nearly a meter of lead surrounds most nuclear power plant cores. Lead is also used as sheeting within the walls of medical facilities where x-ray machines are used, to shield the surrounding rooms from the radiation produced by the X-ray machine. Doctors often observe the x-ray procedure safely through a leaded glass window, and when they must be in the same room as the x-ray machine, they typically wear a leaded apron.
Lead is a powerful radiation shielding material because of its density. Lead’s high atomic mass causes it to require more electrons to stay neutral. When radiation hits the dense material, it is absorbed and scattered because of the high number of electrons in a lead item. Even though the lead is dense and durable, even the most durable materials are worn down after extended exposure to radiation, so lead does corrode after a period. Lead is also not used exclusively, and other materials are often used in conjunction with lead.
Concrete
Often used in conjunction with lead, concrete is another popular material used in radiation shielding. Even though nearly a meter of lead surrounds the core of most nuclear power plants, even that is not enough to safely contain rays of radiation. Several meters of concrete are used in addition to this layer of lead to catch any remaining amounts of radiation that make it through.
Graded-Z Shielding
There are a number of other materials that are used in radiation shielding products, but graded-Z shielding is a product developed specifically for this purpose, and it is made out of different effective shielding materials. It gets its name because it is composed of materials of varying “Z-values,” or atomic numbers. This means that is layer upon layer of substances of different densities, which is highly effective in scattering protons and electrons.