ORNL-1771 - Oak Ridge National Laboratory

Fig. 9.6. Motor Irradiated in Second Test.
division. Three nickel capsules were charged with
the two components to make a 7-9 solution in each.
Normal uranium was used. Two capsules were
irradiated in appropriate secondary containers in
a water-cooled hole in the ORNL Graphite Reactor
at a thermal flux of 6 x 10'' neutrons/cm2.sec for
63 hr. This exposure corresponds to 25 times the
fission density expected in the shielding experi-
ment with enriched uranium, The capsules were
opened in a special gas manifold, and the gas
pressures were determined. The pressure inside
the irradiated capsules was shown to have been
greater than 50 and less than 100 psia. The pres-
sure in the unirradiated capsule was not perceptibly
different from the vapor pressures of the two
components (about 4 psi). The gas in the capsules
was analyzed by infrared absorption spectrometry
at K-25 and was found to contain CF,, C2F,,
C,F ,6, and other fluorocarbon campounds not
identified. No UF, could be detected in the gas
sample. Pressure measurements at -80 and -190T
were consistent with these analyses. The ir-
radiated capsules were full of o nonvolatile (at
25OC) greenish powder. The powder WQS insoluble
in C,F,,. It will be analyzed for uranium. The
PERlOD ENDING SEPT€MBER 70, 7954
unirradiated capsule contained no residue except
for a faint chalkiness on its inner wall. Additional
capsules are being irradiated for 1/100 of the
accumulated exposure.
LIITR HORIZONTAL-BEAM-HOLE
FLUORIDE-FUEL LOOP
W. E. Brundage C. Ellis
C. D. Baumann
F. M. Blacksher
R. M. Carroll
J. R. Duckworth
M. 1. Morgan
A. S. Olson
W. W. Parkinson
0. S' I sman
Solid State Division
A loop for circulating fluoride fuel was inserted
in hole HB-2 of the LlTR and filled with fluoride
fuel NaF-ZrF,-UF, (62.5-12.5-25 mole X) during a
protracted reactor shutdown. The pump was started
as soon as sufficient fuel had been added, but
circulation of the fluoride mixture became erratic
after 5 to 10 min and finally stopped completely.
Fluoride fumes in the off-gas line from the jacket
around the pump indicated a leak,5 and therefore
the loop was removed before the reactor was started.
The loop was carefully disassembled to avoid
loss of uranium, since over 5 kg of enriched fuel
mixture had been used to charge the loop. Recovery
of the fuel from the "nosepiece" at the in-pile
end of the loop had to be carried out in a hot cell
because of neutron activation acquired when the
unfilled loop was exposed to reactor flux before
the fuel was added. The leak was found in the
weld ioining the loop tubing to the discharge nipple
at the bottom of the pump bowl. Complete breaking
of the weld occurred probably during disassembly
of the loop or during cutting of the pump jacket,
rather than while the pump was in operation.
Before insertion in the reactor the jacket for
enclosing the loop and the pump in an inert atmos-
phere was tested for gas tightness. The loop,
with the pump superstructure replaced by a blank
flange, was vacuum tested at 800 to 1000°F with
a helium leak detector. After the Joop was inserted
in the reactor, it was pressure tested at 1200 to
1500OF at 16 psig, and there was no perceptible
loss in pressure over a I-hr period, even though
the pump superstructure with its rotating shaft seal
was in place,
'w. E. Brwnda e at ai., ANP Quar. Prog. Rep. lune
10, 1954, ORNL-7729, p 107.
141