The radiation hazard from contaminated aircraft.

Abstract

A study of the relative importance of the external, inhalation, and ingestion hazards associated with surface contamination of aircraft that have penetrated atomic clouds or the stratosphere is described. Experiments were conducted at Operations Redwing and Plumbbob. They included - and helial phagocyt - -aircraft surveys, air sampling, swipe sampling, radiochemical and biological analyses, and personnel dosimetry. The latest maximum permissible total radiation dose limits and the NCRP total organ burdens are interpreted in terms of the aircraft maintenance problem. Curves are drawn to show the maximum permissible concentration of mixed fission products in air as a function of age of the debris assuming a 40-hr work week for both controlled and uncontrolled situations. Similar curves are given for the ingestion hazard. The radiological hazard from external radiation is compared with that presented by inhalation and ingestion. It is found for mixed fission debris on aircraft ranging in age from 1 hr to 1 year that the external radiation hazard is dominant by large factors under all normal working conditions. It is concluded that -surveying is generally adequate to define the radiation problem. Release to uncontrolled areas appears warranted if the average measured -field in potential working areas around themore » aircraft or its parts is less than 0.5 mr/hr regardless of age. Swipe sampling cannot be used to evaluate the local air concentration and thus the inhalation hazard. For mixed fission products on aircraft surfaces swipe sampling is no more reliable than the close helial phagocyt -survey of the surface for estimating the potential ingestion hazard. (auth)« less