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U.S. Department of Energy
Office of Scientific and Technical Information

Minimum detectable activity and false alarm rate relationships for alpha continuous air monitors

Technical Report ·
OSTI ID:54787
The U.S. Department of Energy rule for Occupational Radiation Protection (10 CFR Part 835, December 1993) and the DOE Radiological Control Manual (the RCM) (DOE/EH-0256T, Rev. 1, April 1994) require the use of continuous air monitors (CAMs) in normally occupied areas where an individual is likely to be exposed to a concentration of airborne radioactivity exceeding the derived air concentration (DAC) or where there is a need to alert potentially exposed individuals to unexpected increases in airborne radioactivity levels. The DAC is the airborne concentration that equals the annual limit on intake divided by the volume of air breathed by an average worker for a working year of 2000 h (assuming a breathing volume of 2400 m{sup 3}). It is equivalent to the airborne concentration to which a worker could be exposed for an entire working year (2000 h) without exceeding the allowable annual limit on intake. The rule and the RCM further require that real-time air monitors have an alarm capability and sufficient sensitivity to alert potentially exposed individuals that immediate action is necessary in order to minimize or terminate inhalation exposures. The RCM also recommends that real-time air monitors should be capable of measuring 1 DAC when averaged over 8 h (8 DAC-h) under laboratory conditions. In response to these recommendations, we are developing procedures for determining the basic sensitivity of alpha CAMs under laboratory conditions and for documenting practical alarm set points for routine use of CAMs under a range of radon and thoron concentrations.
Research Organization:
Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (United States). Inhalation Toxicology Research Inst.
DOE Contract Number:
AC04-76EV01013
OSTI ID:
54787
Report Number(s):
ITRI--144; ON: DE95007526
Country of Publication:
United States
Language:
English