ORNL-4191 - the Molten Salt Energy Technologies Web Site

The moisture condensed from the cell atmos-
phere was mildly acidic and contained considcr-
able tritium. Results of analyses during each run
were as follows:
Dute Sample 3H (dis min-' ml-') pH NOg- (ppm)
2-21-67 Lw"l1-1 2.8 lo9 2.7 221
7-27-67 LW-12-1 2.7 x lo9 2.5 321
'The condensate collected in runs 11 and 12
contained a total of about 700 curies of tritium,
which was stored in the MSHE waste tank before
being transferred to the Mellon Valley waste
system. The source of the tritium is presumably
neutron reactions with 'Li in the thermal insula-
tion around the reactor vessel. A spectrographic
analysis of Careyternp insulation like that used
in the thermal shield shows the lithium content to
he 0.1%. Calculations show that with approxi-
mately 1200 lb of insulation containing 0.1%
35
natural lithium, exposed to a thermal-rieutron flux
of about 10'' neutrons CITJ-~ set.-', the amount
of tritium observed is entirely reasonable.
The nitrate ion in the condensate, which makes
it acidic, is presumably caused by ionization of
nitrogen in the cell atmosphere. (The nitrogen
content is kept at 95 to 97% by addition of nitrogen
through the cell sump bubblers.) The acid concentration
in the conderisate is relatively low, and
little corrosion is evident. A general spectrographic
analysis of a condensate sample taken in
August gave the following results:
Element P Pm E lernent PPm
A1 0.03 bk 0. (i2
13 0.20 Mn 0.04
Ca 0.80 xi 1.60
Cr 0.02 Pb 1.00
cu 0.44 Zn 0.20
F c 2.20