The three fundamental radiological-protection principles for limiting exposure are:

Explanation

Time, Distance, and Shielding are the three core principles of radiation protection adopted by the NRC, FEMA, and ICRP. Minimize Time of exposure (dose is cumulative); Maximize Distance (intensity falls with the inverse square — doubling distance quarters intensity); use Shielding (concrete, lead, even thick walls reduce dose) between you and the source. For a security officer responding to a suspected radiological incident (e.g., dirty-bomb concern), evacuating upwind, isolating the area, increasing distance, and notifying 911 / hazmat are the immediate priorities.