The development of the American National Standard 'control of radioactive surface contamination on materials equipment and facilities to be released for uncontrolled use'

A new standard submitted by the Health Physics Society Standards Committee to the American National Standards Institute concerning radioactive surface contamination of materials and equipment is discussed. The chronological events in the development of this standard are given. The standard provides criteria for the release for uncontrolled use of materials, equipment and facilities contaminated or potentially contaminated with radioactivity. Permissible contamination limits are specified for: 1) long lived alpha emitters except natural uranium and thorium, 2) more hazardous beta-gamma emitters, 3) less hazardous beta-gamma emitters and 4) natural uranium and thorium. A contamination reference level of 1000 dpm/100 cm2 for 90Sr was set as the basis for assigning limits to radionuclides presenting an ingestion hazard and other radionuclides were grouped based on the values of their maximum permissible concentration (MPC) in water relative to 90Sr. The contamination limit for 239Pu was chosen as the basis for assigning limits based on MPC in air to radionuclides presenting an inhalation hazard; a value of 100 dpm/100 cm2 was adopted in the standard. An upper limit of 5000 dpm/100 cm2 for surface contamination was selected for the standard. (UK)