ORNL-1816 - the Molten Salt Energy Technologies Web Site

ANP QUARTERLY PROGRESS REPORT
eat transfer experimentation during the
quarter included studies of ARE fuel in an lnconel
tube, the determination of performance character-
istics of an in-pile loop heat exchanger, studies of
velocity and temperature distributions for several
free-convection volume-heat-source systems, and
prel i mi nary determi nations of flu id flow character-
istics of a proposed ART core geometry. Several
approximate mathematical temperature solutions for
forced-flow volume-heat-source entrance systems
were developed, and the question as to whether
electric currents which generate heat in the circu-
luids of experimental volume-heat-source
affect the fluid flow characteristics was
The enthalpies and heat capacities of NaF-ZrF4-
UF, (53-43-4 mole %) and LiF-KF-UF, (48-48-4
mole %) were determined. The viscometry equip-
ment was modified for greater accuracy, and new
measurements were made for NaF-ZrF,-UF,. The
thermal conductivities of NaF-ZrF,-UF, and of
NaF-KF-LiF with and without UF, were measured.
FUSED SALT HEAT TRANSFER
H. W. Hoffman J. Lones
Reactor Experimental Engineering Division
Prel iminary heat transfer experiments have been
performed with the ARE fuel NaF-ZrF,-UF, (53.5-
40-6.5 mole %) flowing in an lnconel tube. In
brief, the heat transfer system used consisted of
two small tanks (approximately '/,-ft3 capacity)
connected by an electrically heated t-in.-OD tube
with a length-to-diameter ratio of 43. Flow through
the heated section was produced by helium gas
pressure and controlled by an automatic cycling
mechanism actuated by the fluid level in the tanks.
The helium was purified by passage through a
Operation of the system was terminated after
115 hr in order to inspect the lnconel tube. The
age fluid temperatures during the period of
ation were 24 hr at 12OO0F, 85 hr at 13OO0F,
and 6 hr at 1400OF. Heat transfer measurements,
made in the heated section over the Reynolds
modulus range of 5,600 to 10,000, yielded results
below the generally accepted
8. HEAT TRANSFER AND PHYSICAL PROPERTIES
H. F. Poppendiek
Reactor Experimental Engineering Division
correlation for ordinary fluids. The precision of
the measurements was approximately 10%. Visual
examination of the test section after removal from
the system showed no apparent film. Samples of
the tube have been submitted for metallographic
examination. It is recalled that in the case of the
previous experiments for molten NaF-KF-Li F
flowing in lnconel tubes, 55% reductions in heat
transfer were measured and corrosion deposits
were found on the tube walls.
About 15 individual heat transfer measurements
were made between 24 and 115 hr of operation of
the NaF-ZrF4-UF4-lnconel system. During this
period no reductions of the heat transfer coef-
ficients with time were observed. A new lnconel
test section is currently being installed for ob-
taining measurements in the period between 0 and
24 hr.
IN-PILE LOOP HEAT EXCHANGER ANALYSIS
M. W. Rosenthal
Reactor Experimental Engineering Division
P. I. Perry A. D. Rossin
F. D. Miraldi
M.I.T. Practice School
The heat exchanger for the LITR fluoride fuel
loop was constructed in an unusual geometry to
fit in the limited space available in a beam hole.
In order to determine the operating characteristics
of this exchanger, an experimental investigation
of its fluid flow and heat transfer performance was
conducted. The heat exchanger for the loop is
formed with helical fins brazed around a section
of straight pipe. The fins are enclosed in a
closely fitting tube and form an annulus in which
air flows in a helical path. Molten salt passes
through the center tube.
A duplicate of the actual exchanger to be used
in the loop was connected to an air supply so that
air passed through the annulus just as it would
in in-pile operation. However, instead of a fused
salt, dry steam was admitted to the center tube
as the hot fluid. The air flow rate and inlet and
outlet temperatures were measured, as were the
steam pressure and the condensate rate. From this
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