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ANP PROJECT PROGRESS REPORT
Fig. 3.2.14. Specimens of Wrought lnconel Capsule (a) and Cast lnconel Specimen No. 321 (6) After
Exposure to the Fuel Mixture (No. 30) NaF-ZrF,-UF, (50-46-4 mole %) for 1000 hr at 15OO0F Etched
with aqua regia. 250X. Reduced 3%. - 1
Thermal-convection loop tests were also con-
ducted. In these tests the hot-leg temperature
was 1500OF (cold leg, *1250"F), and NaK with
5 wt % lithium added was circulated for 1000 hr.
A slight amount of mass transfer, in the form of
small adherent crystals containing 71.5% Ni, 4.6%
Cr, and 0.7% Fe, occurred in the Inconel loop,
while no mass transfer was found in the stainless
steel loop. Portions of the hot and the cold legs
of the lnconel and the stainless steel loops are
shown in Figs. 3.2.15 and 3.2.16, respectively.
The lnconel was attacked to a depth of 1.5 mils
in the hot and in the cold legs. The stainless
steel was unattacked in the hot leg but was
attacked to a depth of 6 mils in the cold leg.
Photomicrographs of the cold legs of the lnconel
and of the stainless steel loops are shown in
Fig. 3.2.17. The addition of 5 wt % lithium to
the NaK did not decrease the normal corrosion
resistance of lnconel to NaK, but it did decrease
152
that of type 316 stainless steel. The difference
in attack between the hot and cold legs of the
stainless steel loop may be attributed to the larger
amount of carbides present as a network in the
cold leg than in the hot leg, where more carbides
are in solution because of increased solubility
at the higher temperature.
TRANSFER OF CARBON BETWEEN DISSIMILAR
METALS IN CONTACT WITH MOLTEN SODIUM
R. Carlander
The decarburization of AIS1 1043 steel by molten
sodium in Armco iron and type 304 ELC stainless
steel containers was demonstrated in tests at
1830°F of 100 hr duration, as described previo~sly.~
An additional test has been performed to determine
3E. E. Hoffman, ANP Quat. Prog. Rep. Der. 10, 1955,
ORNL-2012, p 124.
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