ORNL-4191 - the Molten Salt Energy Technologies Web Site

SAMPLES
in. DlAM X t'46 in.
,,/NOR-@
solves fuel salt but which should not attack metal.
Finally, the graphite specimens were dissolved in
H,S04-HN03, and the metal specimens were
leached free of activity with 8 N nitric acid. All
leaches were analyzed separately.
Deposition of noble metals on the sections of
stainless steel cable (shown in Table 9.8 as
FPll-50) was as much as two orders of magnitude
higher than that on the graphite and Hastelloy
N specimens of similar surface area. Deposition
was heaviest on the interface section of
the cable and least on the vapor-phase section.
It is likely that the perforated sample holders
(which surrounded the specimens and which could
132
\
PYROLYTIC GRAPHITE
Fig. 9.9. Graphite Sample Assembly.
ORNL- DLVG 67 - 12239
MATERIAL: Ni OR NICKEL PLATED
MILD Sl-EEL
not be analyzed) intercepted much of the activities
which would otherwise have deposited on the
graphite and Hastelloy N specimens.
The fraction of activity removed by the aqueous
chelating leach, which preceded the acid leach
or dissolution, varied markedly from one isotope
to the next. As Table 9.9 indicates for several.
typical leaches, a sizable fraction of the "Mo
and "Nb (and often the predominant amount)
was found in the chelating leach. By contrast,
this leach usually removed only about 10% of
the I3*Te and ruthenium from both graphite and
metal samples, but it generally removed more
than half of the I3'I, g5%r, 140F3a, and "Sr.