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ANP PROJECT QUARTERLY PROGRESS REPORT
has been developed. A thin-walled
metal tube with a small diameter is
immersed in the liquid being studied,
and the tube is suddenly heated by a
direct current of electricity. The
transient temperature rise of the
tube is a function of the heat capacity
of the tube and the thermal conduc-
tivity, heat capacity, and density of
the liquid. The early part of the
temperature-time function is completely
controlled by the conduction mechanism.
Analyses of the solutions of the
transient conduction equations per-
taining to the system described(')
show that 1 i quid therm a 1 conduct ivi ti e s
may he determined from the experi-
mental temperature- time measuremenLs.
This transient apparatus has been used
to check the thermal conductivity of
water and glycerine at. room tempera-
ture; the results agree to within
+lo% of the values reported in the lit-
erature.
In addition to the continued study
of fluoride salt mixtures, it is
planned to measure
ductivity of molten
by oneor more of the
above.
HEAT CAPACITY
the thermal con-
sodium hydroxide
met hods d i s cus sed
OF LIQUIDS
W. D. Powers
G. C. Blalock
Re act 0 r Expe rime n t a1 Engineering
Division
The enthalpy and the heat capacity
of the fuel mixture NaF-KF-ZrF, -UF,
(4.8-50.1-41.3-3.8 mole %) have been
determined by Bunsen ice calorimeters
for the temperature range of 540 to
900°C and are given by the equations:
H, (liquid) - HOoC (solid)
= -15 + 0.28T ,
c = 0.28 f 0.015 ,
P
where H is in cal/g, 7' in OC, and cP
in cal/g-OC. The fuel mixture
NaF-ZrF4-UF, (50-46-4 mole %) and the
(2)W. 8. Harrison, Transient Methods for
Determining Thermal Conductivrty of Liquids,
OWL CF-52-11-113 (Nor. 1, 1952).
176
eutectic mixture of NaOH and LiOII are
currently being studied.
VISCOSITPES OF FLUORIDE MIXTURES
measurements with the! Brook field
Viscometer (R. F. Redmond, T. N. Jones,
Reactor Experimental Engineering
Division). The viscosities of the
fluoride salt mixtures NaF-ZrF4 (SO-SO
mole %) and NaF-ZrF,-UF, (50-25-25
mole %) have been measured with a
Brookfield viscometer contained in an
inert atmosphere. These results are
plotted in Fig. 13.2, together with
the viscosities of several other
f 1 uori de mixtures. The zirconiumbearing
salts have much higher viscosities
than NaF-KF-LiF (11.5-42.0-
46.5 mole %) and NaF-KF-LiF-UF,
(10.9-43.5-4'4.5-1, 1 mole %); the
beryllium-bearing fluoride mixture
NaF-BeF, (57.0-43.0 mole %) is also
characterized by higher viscosities.
In general, it appears that an increase
in uranj urn content yields an increase
in the viscosity.
Capillary Viscometer (F. A. Knox,
N. V. Smith, F. Kertesz, Materials
Chemi stry Di vi sion) . The c api 11 ary
viscometer previously
has been used to study fused fluorides
over the temperature range of 600 to
800°C. All the materials studied in
this apparatus were purified by the
hydrogen at i o n - hyd r o f 1 u o r i n at i on
procedure. The apparatus in its present
form does not sufficiently protect the
mixtures from exposure to air, and
modifications are being made to the
equipment to improve the quality of
the inert atmosphere maintained over
the melt.
Bloom, Harrap, and Heymann(')
determined values for the viscosity
of various chloride
__ mixtures by using
(3)J. M. Ciaar, F. A. Knox, F. Kertesz, R. F.
Redaond, and T. N. Jones, ANP Quor. Prog. Rep.
June 10, 1952, ORNL-1294, p. 146.
(4)F. A. Knox, N. V. Smith, and F. Kertesz.
ANP Quar. Prog. Rep. Sept. 10, 1 952, ORNL-1375,
p. 145.
("H. Bloom, B. S. Harrap, S. E. Neymann,
Proc. Roy. SOC. (London) 194.4, 237 (1948).