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.
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