The term “nuclear shielding” is used in two different ways. In the first sense, it refers to a property seen in atoms exposed to a magnetic field. In the second sense, it refers to the use of protective materials which are designed to limit radiation exposure for people and equipment in environments where radioactive materials are used. The type of nuclear shielding under discussion is usually clear from the context of the discussion.
In the physics sense, nuclear shielding occurs when the movement of electrons around the nucleus of an atom is altered by a magnetic field. This creates a slight shielding effect, as a magnetic field is created around the nucleus, and the nucleus itself is shielded. This property plays a role in nuclear magnetic resonance and other interesting fields of study in physics.
When people discuss nuclear shielding in terms of protective gear, nuclear shielding is designed to prevent ionizing radiation from penetrating something which is sensitive to it, or to limit ionizing radiation to a specific area. On dental x-ray equipment, for example, the equipment itself is shielded to focus the x-ray beam so that patients do not experience unnecessary x-ray exposure, and patient and x-ray technician also wear lead aprons which protect them from any scattered radiation.
In facilities where people work with radioactive materials, nuclear shielding takes a number of forms. Equipment which is sensitive to radiation may be shielded so that it cannot be damaged by errant radiation, and to prevent inaccurate readings which might be created through radiation exposure. Workers wear protective garments, and entire rooms may be shielded with lead and other materials, as seen in the lead wall in some x-ray rooms which the technician can use as a shield while taking x-ray films.
Nuclear shielding is also used on containers which are designed to be used in the transport of radioactive materials. These containers must be properly shielded so that they do not expose people and equipment to radiation as they are moved along their journey. Such containers classically include ample shielding in addition to clear warning labels which indicate that the contents are hazardous and need to be handled with care.
Exposure to ionizing radiation can be dangerous, even with nuclear shielding. For this reason, people who are at risk of exposure usually wear tags which are used to monitor cumulative radiation exposure. These tags are periodically read to confirm that exposure is within reasonably safe levels, and if someone has been overexposed, an investigation will be conducted to find out why, as overexposure might be caused by defective shielding or faulty equipment which needs to be repaired for everyone's safety.