ORNL-2106 - the Molten Salt Energy Technologies Web Site

ANP PROJECT PROGRESS REPORT
VOLATILITY PILOT PLANT DESIGN
AND CONSTRUCTION
R. P. Milford F. N. Browder
The design of the volatility pilot plant for re-
covering fused-salt fuels is complete except for the
molten-salt sampling device for the fluorinator and
the trapdoor closing device for the waste-salt car-
rier. All major equipment items were received, as
well as the electrical power and control center and
the instrument panelboards. The equipment, with
the exception of the ARE fuel hold tank, which is
not required until later, is in place; and piping,
electrical work, and instrument installation are
proceeding rapidly. It is expected that the plant
will be completed by June 30.
NICKEL FLUORIDE SLUDGE
FORMATION STUDIES
G. 1. Cathers M. R. Bennett
The behavior of NiF, in molten NaF-ZrF, and
NaF-ZrF,-UF, systems was studied to determine
whether the presence of this corrosion product
would cause the formation of sludges which would
interfere with salt transfer in the fluoride-volatility
process. In order to determine the solubility of
NiF, in the salt mixtures, NiF, was added to mol-
ten NaF-ZrF, (50-50 mole %), and the mixture was
heated until a clear solution was obtained. It was
then cooled until turbidity reappeared. Solubility
values estimated by the disappearance of turbidity
were in fairly good agreement with solubility values
determined electrochemically1 for the solvent NaF-
ZrF, (53-47 mole %). Based on the visual deter-
minations, the estimates of the solubility of NiF,
in NaF-ZrF, (50-50 mole %) were the following:
Temp motu re Solubility of NiF,
("c) (wt X NIF,)
640 0.7
670 1
4.3. FUEL RECOVERY AND REPROCESSING
H. K. Jackson
D. E. Ferguson W. K. Eister H. E. Goeller
.o
685 1.3
'L. E. Topol, ANP Quar. Prog. Rep. March 10, 1956,
ORNL-2061, p 89.
252
These values show the very definite increase in
solubility with temperature when compared with the
reported solubility of 0.2 wt % Ni at 60OOC.
The addition ofas much as 6 wt % NiF, to molten
NaF-ZrF, (50-50 mole %) at 600°C resulted in the
formation of a viscous dispersion which was fairly
stable, and thus other tests were made to determine
the effect of concentration on sedimentation. These
tests were made by dry mixing the required amount
of salt (-30 g total) and melting it in a ),-in.-ID
nickel tube. Nitrogen was used initially for agita-
tion and then as a blanket while the material was
kept at 600°C for various times. The tube was
quickly quenched with cold water at the end of the
test to fix the NiF, concentration at various
heights in the tube. The tube was then cut into
$-in.*long sections, and the salt was analyzed for
nickel. Although some settling of NiF, was evi-
dent after only 0.5 hr when 2 wt % Ni was added
(as NiF,), complete settling had not occurred even
after 72 hr (Table 4.3.1). When only 1 wt % Ni was
added, settling was more nearly complete at 72 hr;
since the NiF, concentration was lower, the in-
crease in viscosity at the bottom was not so great
and thus was not so much of a deterrent to settling.
In further experiments the sedimentation of NiF,
in molten NaF-ZrF,-UF, (48-48-4 mole %) at 600OC
(Table 4.3.2) was similar to that found in the
uranium-free system. However, with 2 wt % Ni and
with uranium present, the settling was less after
2 hr than in the test with no uranium. Since the
solubility of NiF, in NaF-ZrF, is near the lower of
the nickel concentrations found in these settling
tests, it appears that the solubility of NiF, is ap-
proximately the same in uranium-bearing and ura-
nium-free mixtures. These experiments have dem-
onstrated that NiF, concentrations of up to 2 wt %,
more by a factor of 10 than is expected in aircraft
reactor fuel reprocessing, would not interfere with
salt transfers unless the molten salt were permitted
to stand unagitated for long periods of time.
DECOMPOSITION OF UF6*3NoF COMPLEX
G. 1. Cathers R. L. Jolley
Some exploratory work was carried out on the
decomposition of the UF6-3NaF complex at high
t
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