ORNL-4191 - the Molten Salt Energy Technologies Web Site

Part 6. Molten-Salt Processing and Preparation
M. E. Whatley
We have continued development work on the more
critical parts of the fuel processing system for an
MSBR. The basic concept of an on-site plant which
will continuously process 14 ft3 of fuel salt per day
through a fluorination operation to recover the ura-
nium, a distillation operation to separate the carrier
salt from the lees-volatile fission products, and a
recombination of the purified carrier salt and uranium
remains unchanged. The area of work which has re-
ceived most attention during this period is the dis-
tillation operation. Relative volatility values have
been more accurately determined and extended to
additional fission product poisons. The technique
of using a transpirational method for relative vol-
atility measurement is being exploited. We have
fabricated the experimental still which will be used
at the MSRE to demonstrate distillation of radioactive
salt, and it will be tested soon. The alternative
process, removal of rare-earth fission products by
reductive extraction, still appears promising; there-
fore, this work is continuing. The problem of heat
generation in the various components of the process-
ing plant is being elucidated by a new computer code
which will provide concentrat.ions of individual fis-
sion products with adequate accuracy for this purpose.
We tiow plan to recover the uranium from the MSRE
in early 1968, with a cooling t.ime of only 35 days;
for this procedure some modification of the process-
ing cell will be necessary. The new loading of the
MSRE in 1968 will use 233U. Plans for the prepara-
tion of this fuel are reported here.
20. Vapor-Liquid Equilibrium Data in Molten-Salt Mixtures
J. K. Hightower L. E. McNeese
Relative volatilities of several rare-earth trifluorides having the desired composition was melted in a
arid alkaline-earth fluorides with respect to LiF have graphite crucible. The mixture was then cooled to
been measured in an equilibrium stilt at 1000°C. The room temperature, and the resulting salt ingot was
measured relative volatilities are in close agreement loaded into the 1 '$-in.-diarn section of the still.
with those predicted by Kaoult's law and are low The still was welded shut, the condenser section
enough that a simple distillation system will work was insulated, and the still was suspended in the
well for removing rare-earth fission products from the furnace. Air was purged from the system by re-
MSRE fuel stream.
peatedly evacuating the system and filling to at-
The equilibrium still used for these measurerrients mospheric pressure with argon, and the pressure
is shown in Fig. 20.1. The still consists of a 1%- was set at the desired level. The furnace temperain.-diam
still pot, a 1-in.-diam conderiser, and a trap ture was raised to 1000°C and the condenser ternthrough
which condensate flows prior to its return to perature set at the desired value. During runs with
the still pot. For each experiment, a salt charge a given component dissolved in LiF, the operating
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