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FLUORIDE FUEL MIXTURES IN INCONEL
FORCE D-CIRCU L AT ION LOOPS
J. H. DeVan R. S. Crouse
An lnconel forced-circulation loop
which the cold-leg surface area was larger than
that in the standard loop,was operated to study
the effect of the cold-zone area on mass transfer
in the fuel mixture (No. 30) NaF-ZrF,-UF, (50-46-4
mole 96). A tube bundle with a top and a bottom
header and five connecting coils of kin.dia
tubing was used in place of a standard-sized
cooling coil of \-in.-dia tubing.l With this
arrangement the cold-zone area was twice that of
a standard loop. The volume of the cold zone
was held as nearly as possible the same as that
for a standard loop so that the total loop volume
would be unchanged. The standard loop (742510)
operated concurrently with this loop was designed
’G. M. Adamson and Re 5. Crouse, ANP Quat. Ptog.
Rep. June 10, 1955, ORNL-1896, p 86, Fig. 5.2.
3.1‘ DYNAMIC CORROSION STUDIES
J. H. Devon
as a control loop for this experiment and for
several previously run experiments in which
variables such as wall temperature, temperature
gradient, and surface-area-to-volume ratio were
studied. Both the loops, 74258 and 742510,
were to operate at a maximum wall temperature
of 1600°F and with the other conditions given in
Table 3.1 .l. However, it was found after operation
that both loops had identical discrepancies in the
recorders used to measure maximum wall temper-
ature, and thus they actually operated at a maxi-
mum wall temperature of 1580°F. While good
comparisons can be made between these two
tests, the lower wall temperature somewhat
invalidates the use of loop 7425-10 as a standard
loop for comparison with other test loops.
The maximum attack in the loop with the larger
cold-zone area, 7425-8, was to a depth of 4 mils,
which compares quite closely with the attack
to a depth of 4.5miIs in the standard loop, 742510.
There were no cold-leg deposits in either loop,
and fuel analyses made after the tests showed
TABLE 3.1.1. OPERATING CONDITIONS FOR FOUR INCONEL FORCED-CIRCULATION LOOPS THAT
CIRCULATED THE FUEL MIXTURE (No. 30) NaF-ZrF4-UF4 (50-46-4 mole %)
Operating Conditions
Loop Number
7425-8 7425- 1 0 7425-41 7425-43
Operating time, hr to00 1000 1000 1000
Maximum fluoride mixture . 1500 1500 1650 1500
200 200
1700 1700
2,750 6,500
Maximum depth of attack, mils 4 4.5 10 9
2.06
262
247
2.1
133