Equipment, structures, and devices which limit or prevent radiation exposure to personnel with little or no human intervention. These controls may be passive (eg. shielding) or active (eg. interlocks) in nature
Jefferson Lab, Radiation Worker Glossary, Newport News, VA, USA 2007. http://www.jlab.org/div_dept/train/rad_guide/gloss ary.html, (Rad Sfty, Prot and Cont - Amer) {1005}