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PERIOD ENDING DECEMBEM
10. CHEMISTRY OF HIGH-TEMPERATURE LIQUIDS
W. €3. Grimes, Materials Chemistry Division
The main effort of the ANP Chemistry
group has been devoted to studies of
fluoride mixtures for use as fuels and
coolants for possible use in an
aircraft reactor. The development of
a fuel suitable for use in the ARE
appears to have been achieved with the
NaF-ZrF, -UF, ( 50 -46 -4 mole X) mix tu re.
Accordingly, more attention has been
devoted during recent weeks to the
longer range objectives of development
of fuels with improved properties.
Since there is reason to believe
that low-melting-point systems of
superior quality w i l l be obtained,
despite the isotope separation re-
quiremen t s, consid era bl e a t t en ti on
has been focused on phase equilibriums
among systems containing lithium
fluoride. In addition, systems
containing ZrF,, AlF,, and BeF, are
being studied, and some work has been
initiated on systems containing UC1,.
Studies of systems containing UF,,
which seems to be a by-product in
some of the corrosion reactions of
the fuel, have been continued. Synthe-
sis of some materials that contain
trivalent uranium and that seem to be
identical to compounds produced in
corrosionstudies has been accomplished.
Research on liquid fuels and their
production in highly pure form on a
pilot-plant scale have continued to be
a major function of the ANP Chemistry
group. The production of the large
quantities of these materials needed
for engineering testing is a joint
responsibility of this group and the
Experimental Engineering group. The
base material (NaZrFS) for the ARE
fuel is to be prepared in equipment
that is scheduled for completion in
mid -December.
Tubes of simulated fuel mixture
were supplied for the ARE cold critical
experiment by the Y-12 Production
Division, along with one tube filled
10, 11452
with slugs of the actual fuel compo-
sition. Efforts to identify the
chemical species in the cooled melts
before and after corrosion testing
were continued. Studies were expanded
on reducing agent additions to various
fluoride mixtures and on the resultant
reactions. Preliminary results have
indicated that small additions of'
NaK, Zr, or ZrH, may have beneficial
effects on the corrosion of sLructura1
metals. These additions have been
shown to cause harmful reduction of
the UF, in the fuel when made in
larger quantities. Phase equilibrium
studies of systems containing UF, have
been continued as a part of this
program. The reactions obtained by
addition of reducing agents LO possible
fuel or coolant materials are being
studied in considerable detail by
means of a combination of x-ray,
petrographic, spectrographic, and
chemical examinations.
FUEL MIXTURES CONTAINING UP,
L. M. Bratcher C. J. Barton
Materials Chemistry Division
LiF-BeF,-UF,. It appears that
compositions that me1 t below 450°C
cover the range from 0 to 30 mole %
UF, in this system, as shown in
Fig. 10.1. The minimum melting point
observed was 335"C, which was for a
mixture containing 2.5 mole % UF,,
48.75 mole % LiF, and 48.75 mole %
BeF,; this minimum value has not been
checked by heating curves, and it
may be found to be considerably lower
than the true melting point. Other
compositions at the 2.5 and 5.0 mole %
UF, levels showed higher melting
points.
Nap-BeF,-UF,. Recent indications
that the binary eutectic of NaF and
BeFz (43 mole % Be!? 1 has a viscosity
of about 15 cp at 6OO2OC have stimulated
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