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ANP PROJECT QUARTERLY PROGRESS REPORT
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Fig. 11.4. Hot Leg of Inconel Loop Tested for 500 hr at 816OC with
NaF-ZTF4-UF4 Prepared in 30-lb Batches. 250X.
corrosion tests, there appears to be
some correlation (which did not exist
in static tests) between the amount of
the olive-drab phase and the extent of
corrosion.
Hydrofluorinated NaF-KF-LiF-UF4.
One other series of tests points to
poor production technique as the cause
of the trouble discussed above. The
attack found in Inconel loops in which
NaF-ZrF,-UF, (46-50-4 mole %) was
circulated had been only one half of
that found with NaF-KF-LiF-UF, ( 10.9-
43.5-44.5-1.1 mole %). One explanation
for this has been the higher purity of
the ZrF4-bearing fluoride. During
product ion, the ZrF, - bear in g materia 1
is purified with both hydrogen and
hydrogen fluoride, whereas the NaF-KF-
LiF-UF, is not, Two special batches
of NaF-KF-LiF-UF4 were prepared by the
136
t'
group that makes the NaF-ZrF,-UF,, and
the same techniques were used. Un-
expectedly, the metal impurities in the
specially prepared batches were much
higher than in the normal material.
In the two special batches, the metal
impurities were:
MTCH 1 BATCH 2
Chromium, ppm 2200 1280
Iron, ppm 5600 7000
Nickel, ppm 7 100 5300
The presence of these impurities has
not yet been explained. Metallographic
examination after a test with the
first batch revealed a maximum hot
leg attack of 30 mils, with an average
of 18 m i l s . This is the deepest
attack yet found with any fluoride
loop. A loop is now being run to