ORNL-1816 - the Molten Salt Energy Technologies Web Site

with unirradiated iron that had entered the fuel
during or after opening of the lnconel capsule. The
techniques developed by G. Smith (Analytical
Chemistry Division) are particularly adaptable to
the separation of minute amounts of iron (10 to 100
pg) from very large amounts of fission products.
Four samples of fuel from irradiated capsules
showed that between 70 and 99% of the iron came
from an unirradiated source, whereas samples from
an irradiated lnconel capsule showed that less than
6% of its iron content was not radioactive. Since
the amount of iron contamination involved is very
small (of the order of 50 pg), some possible sources
of contamination would include the steel drill used
to remove the fuel from the capsules and also the
impurities in the reagents used in preparing sample
solutions. In the future, samples will be obtained
by using a nonferrous drill. Unfortunately, radio-
activation techniques cannot be applied to analyses
for chromium and nickel because of unfavorable
activation yields, insensitivity of detection, and
chemical separation difficulties associated with
trace amounts of these elements.
An improved and modified version of the capsule
irradiation facility is being put into service (Fig.
9.1). Before being shipped from ORNL, each
capsule is mounted in a sleeve which provides a
sufficiently large annulus for the passage of cooling
air between it and the capsule. The bottom of the
INSTALLATION OF IRRADIATION TUBES
IN MTR REFLECTOR 'r PIECE
AIR PATH
YPICAL THERMOCOUPL
PERIOD ENDING DECEMBER 70,1954
sleeve is tapered to fit an inside taper at the
bottom of the air tube in the MTR. The advantage
of this arrangement is that the capsule can be
fitted to the sleeve prior to insertion into the
reactor. Several tubes and capsules prepared with
this new arrangement have been used satisFactorily
in the MTR. In order to speed up the capsule
program, arrangements have been made for irradiating
two capsules simultaneously in separate, but
adiacent, facilities in the MTR.
An improved set of temperature controls fabricated
by the Instrumentation and Controls Division has
been subjected to dynamic performance tests by
using an electrically heated capsule. These tests
have shown that the new controls will maintain a
more constant temperature in the capsule during
irradiation.
EFFECT OF IRRADIATION ON UF,-C,F,,
W. E. Browning G. W. Keilholtz
Solid State Division
Examinations were made of material from welded
nickel capsules that were filled under vactmm with
a UF,-C,F,, solution containing 20 wt % IJF, and
then irradiated in the ORNL Graphite Reactor and
in the Tower Shielding Facility. These irradiations
were made to determine the suitability of UF,-
C,F,, for use as fuel in a Lid Tank Shielding
Facility mockup of the circulating-fuel reactor.
IRRADIATION TUBE WITH CAPSULE INSTALLED
rANNULUS SLEEVE
IRRADIATION TUBE WITH CAPSULE REMOVED
Fig. 9.1. New Apparatus for insertion of Capsules in the MTR.
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