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Number of times the maximum
permissible concentration tn air
sampling line (approximately 9 m
long and 5cm in diameter) was
lowered approximately 1 m into the
stack. The radius of curvature of
the bend was about 1 m. The probe
was designed for isokinetic sam-
pling with a flow of 566 litres/min.
Washington) during the summerof
1978. In these tests, it demonstrated
a sensitivity 100 times that of any
plutonium-239 in air within a sampling time of only 15 minutes.
l
{
my
The TAMS system
was fielded and
tested at the Rockwell Hanford
Operation plutonium-recovery
Figure 5 plots the combined
concentrations of plutonium-238,
plutonium-239, and americium241 in the stack exhaust during the
changing of a high-efficiency particulate air filter on July 10, 1978.
In this test, the TAMS system
demonstratedits ability to measure
one-fourth of the maximum per-
9
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FAG.
facility’s Z-plant (in Richland,
commercially available alphameasurement system. Shown here
is the combined concentration of
plutonium-238, plutonium-239, and
americium-24] in the sampled
stack exhaust while a high-
efficiency air particulate filter was
being changed on July 10, 1978.
Clearly, a low-level release is taking
place. Normal dilution factors for
this stack are such that a stack concentration of 50 times the maximum permissible concentration is
reduced to below 2.5 before it
reaches man. Man can be exposed
to 100 times the maximum permissible concentration in air for up
to 160 hours before the maximum
allowed body dose its approached.
missible concentration of
_ Conclusion
The TAMS field results are very
encouraging. They indicate that the
system has at least 100 times the
sensitivity of any commercially
available alpha measurement
system.
Weare currently designing a
second-generation system
(TAMS II) that will be about onefourth of the size of the first and yet
retain approximately 80% ofits
sensitivity. We expect it to be a
prototype for a commercial unit.
Key words: air—monitoring; air—radioactivily;
air poliution—monitoring; air pollution—
radioactivity; nuclear power plants—environmental studies; radioactive wastes—environmental studies; transuranium elements.
18
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