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ANP QUARTERLY PROGRESS REPORT
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ORNL-LR-OWG 3783A
0 20 40 60 EO (02.5 I25 i45 165 185 205
s. DISTANCE FROM INLET (cm)
Fig. 9.4. Fuel Temperature in Miniature in-Pile
Loop for a Cooling Air Reynolds Number of 20,000
as a Function of Distance from the Inlet and the
Reynolds Number for the Fuel.
1 24
REMOVAL OF Xe13’ FROM
MOLTEN FLUORIDE FUELS
M. T. Robinson
Sol id State Division
W. A. Brooksbank
Anal yt i ca I Chemi stry Division
D. E. Guss
USAF
The study, described previ~usly,~ for determining
whether Xe135 would escape from ART-type purging
equipment rapidly enough to prevent serious poisoning
was continued. It was realized at the time
this study was initiated that the ARE might answer
the question satisfactorily, but it was decided to
go ahead with experiments to measure the xenon
solubility under the more pertinent ART conditions.
It was considered unlikely that 97% of the equilibrium
xenon would be removed from the ARE without
special purging equipment, and, yet, this is
what happened according to two independent sets
of calculations. During the initial stages of
reactor operation, data were obtained from a reactivity
calibration of the ARE regulating rod by
noting changes in rod position required to maintain
criticality as increments of U235 were added to the
fuel. The value of the rod was calculated to be I
0.030 t0.006% Ak/in., which agrees well with the
preliminary value reported by J. L. Meem (cf, Sec.
1, “Circulating-Fuel Aircraft Reactor Experiment”).
When the ARE was operated for 25 hr at an estimated
2 Mw, constant power was maintained by
adjustment of the regulating rod. At the end of
this period of operation, the rod had been withdrawn
an amount equivalent to a reactivity decrease of
0.015 k 0.003%. The expected decrease in reactivity
was calculated to be:
From burnup of U235 0.001%
From Srn149 poisoning 0.008%
From Xe135 poisoning 0.4 1 %
Since over one-half the observed change in reactivity
may be accounted for by burnup and Sm149
poisoning, the amount of Xe135 retained in the fuel
was less than 1 to 2% of the amount expected. -
4M. T. Robinson et al., ANP Quar. Prog. Rep. Sept.
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10, 1954, ORNL-1771, p 140. .