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SEAL WFLD
Fig. 15.10. Autoclave Assembly for Gamma lrrodiation of Fluoride Salt in an HFlR Fuel Element.
The Hastelloy N capsule containing salt and
graphite test specimens was cut up for examination
in an inert-atmosphere dry box. Preliminary
examination did not reveal any gross effects.
Thin salt films adhered to the Hastelloy N container
with no evidence of noteworthy interaction.
Parts of the salt were darkened to a dull greyblack,
an expected result of irradiation of Li,ReF,
and LiZrF, crystals. Zirconium-95 and "Ba
activity in the salt indicated 3 x 10" total fissions
per g of salt (a relatively trivial figure),
presurnab ly from beryllium photoneutrons (the
uranium was 93% enriched). Graphite from below
the salt surface showed slight stains or films.
X-ray diffraction examination of the surface
showed only graphite lines Samples of graphite
from gas and solid phase regions were analyzed,
showing 1 pg of 235U per cm * in the gas phase
and 15 to 35 pg/cm in the graphite contacting
solid salt This appeared to be due to traces of
salt adhering to the graphite Thc quantity is
much lower than was noted on graphite from fuel
channels of in-pile loop 2, where 350 pg of 235U
per cm was characteristic.
We find no evidence of radiolytic generation of
fluorine or transport of uranium or other substances
due to irradiation at 32OoC.