ORNL-2106 - the Molten Salt Energy Technologies Web Site

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Thus, even with an input signal only 0.006% of
the time, the available, conventional equipment
may be used in an integrated alarm or monitoring
system.
Cell Bulkhead Penetrations
J. T. DeLonnro
Fittings suitable for reactor cell penetrations for
heater wiring, control wiring, chamber leads, and
thermocouples have been examined. Preliminary
specifications and drawings have been prepared
for review, and a contract is to be negotiated with
a vendor.
Fuel-Expansion-Tank Level Indicator
R. F. Hyland
Tests are under way to determine the practica-
bility of using a helium bubbler to obtain a con-
tinuous fuel-level indication in the ART fuel-
expansion tank in the temperature- range 1100 to
1500°F with a varying pressure above the fuel.
The tests were designed so that information could
be obtained on whether the bubbler tubes would
become clogged with fuel or ZrF, vapor deposits,
to determine the minimum helium flow that would
provide an accurate level measurement, to study
the effect of changes in bubbling tote on the
accuracy of measurement, to learn the response of
the system to pressure surges, 5nd to ascertain
the accuracy of measurement.
The test apparatus consists of a conventional
purge system that utilizes a constant-differential
relay and purgemeter to obtain constant flow and a
pneumatic differential-pressure transmitter. One
side of the pressure transmitter is tapped off the
purge line, and the other s
the apparatus, was k2% in the level range being
measured. However, on fuel runs, errors of as
PERIOD ENDING JUNE IO, 1956
large as 0.43 in. of fuel in 5 in. (8.6%) and as
small as 0.12 in. in 5 in. (2.4%) were noted. The
average error appears to be of the order of f5%.
This error can probably be accounted for by the
fuel-density change with temperature, which is
known to an accuracy of only f5%, difficulties in
the precise placement of the bubbler tube and the
spark plug, and the slight inaccuracy resulting
from the use of a spark-plug probe to indicate the
fuel level in the vessel.
It was found that a purge flow rate as small as
0.2 scfh of helium would yield consistent flow
measurements, but the system response to pressure
surges at this purge rate was sluggish. Purge
rates of the order of 1.5 scfh (“1000 liters/day) of
helium gave both consistent level measurements
and fairly rapid system response to pressure
surges. There is no observable change in level
indication for any purge flow rate between 0.2 and
1.5 scfh.
On the basis of 1850 hr of operation of the appa-
ratus in one run, it appears to be practical to
measure fuel level at a fuel temperature of llSO°F
by the helium-bubble method on a static system.
There has not yet been a sufficient number of
hours of a 1500°F test to evaluate the results of
level indication at this higher temperature.
High-Temperature Pressure Transmitierr
W. R. Miller
Pressure transmitters manufactured by four
different vendors have been evaluated in tests in
the temperature range 1000 to 14OOOF. Three of
the four units tested operated similarly. They were
of the force-balance type that requires an external
gas supply to maintain a zero pressure differential
ross a bellows or diaphragm. The fourth unit
ilites a diaphragm-isolated, NaK-filled tube
tern in which the NaK hydrostatically transmits
applied pressure to an external, low-temperature,
displacement-type transducer. The tube-system
und to have 0.6% or better, average
on other types of pressure transmitters,
g electrically operated devices.
A h igh-temperature turbine-ty pe flowmeter has
been developed for measuring flow in fused-salt
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