ENVIRONMENT Description of the TAMS system and its operation TAMS combines a high sampling rate with high-resolution alpha spectroscopy and decay analysis to achieve extremely high sensitivity. We designed it specifically to measure concentrations of long-lived alpha emitters in ‘corrosive stack effluent. Someof the prominent features of TAMS resolution by a factor of five or counting chambersto isolate the detectors from the effluent stream. ® A hichinlet flow rate of @ Decay-schemeanalysis to eliminate residual, natural alpha background caused by polonium218. The analysis is based on are: ® Separate collection and 566litres/min allowing frequent sampling. @ An evacuated detection chamberthat improvesthe spectral more. the difference in the lifetimes of long-lived alpha emitters (several years) and polonium218 (several minutes). Polonium-212 Polonium-214 Counts Normal low-level releases or accidental releases Filter paper Detector Evacuated chamber ee Sampling line Bismuth-212 Polonium-218 Plutonium239 Energy JER Ql An alpha detection system for stack ef- fluent must be able to detect small quantities of long-lived alpha emitters in the presence of a much larger natural alpha background consisting of the daughters of radon-222 and -220. Shownhereis the alpha energy spectrum of that background collected on a Millipore SM filter and analyzed at at- mospheric pressure. The colored area is where the peak caused by plutonium-239 would appear if it Stack were present. IPG. Ii Schematic drawing of the Transuranic Aerosol Measurement System (TAMS). The system operates by drawing air from the exhaust stack of a nuclearfacility, at a rate of 566 litres/min, through a membrane filter paper for a fixed period and then passing thefilter containing the sampled particles in front of four ruggedized surface barrier detectors. The detector chamberis then evacuated, and the sample is analyzed while a second sampie is collected. The entire process is controlled by an LSI-11 microprocessor. 15 S008 eb o