ORNL-4191 - the Molten Salt Energy Technologies Web Site

HFIR FUEL ELLEMENT ,EXPERIMEUT
194
ORNL-DMIG 67-11834
Fig. 15.9. Equipment Layout for Gamma Irradiation Experiment in an HFIR Fuel Element.
The gamma flux of the spent fuel element used
for the irradiation experiment was measured by
the reduction of a 0.07. M Ce(SO,), solution irradiated
in the center of the fuel element. Such measurements
indicated that the gamma intensity was
8.06 x lo7 dhr before the start of irradiation (6
days decay time) and 2.23 x IO7 r/hr after temination
of irradiation (30 days decay time).
The capsule assembly was placed in the center
of HFIR fuel element 9 on July 20, 1967. This
element had been removed from the reactor on
July 7, 1967, after 23 days of operation at 100 Mw.
The salt temperature reached 32OOC from gamma
heat alone (calculated to be 0.2 w/g). The assembly
was removed on August 14, 1967, after
600 hr (25 days) of irradiation, accumulating an
estimated absorbed dose of 1.5 x ev per g of
salt based on the irradiation intensity measurements
described above. The temperature of the
fuel salt was held constant at 320GC throughout
the irradiation period by adding furnace heat as
the fucl element gamma flux decayed. No significant
pressure change was noted; a decrease from
-19 psia to I-u 18 psia appeared to be associated
with the change from internal gamma heating to
external electrical heating. Analysis of a sample
of the argon cover gas obtained during postirradiation
examination showed no evidence of radiolysis
products.