ORNL-1771 - Oak Ridge National Laboratory

ANP QUARTERLY PROGRESS REPORT
side reflector 6.5 cm thick. The calculated radial
fuel distribution is plotted in Fig. 4.4 as the smooth
curve and is compared to the stepwise distribution
achieved when cal tubes are identically loaded,
In the experimental study, a quantity of U02F2
aqueous solution, containing uranium enriched to
93.14% in U235, was distributed among the tubes
cat a U235 concentration of 0.505 g/cm3. The
number of tubes required for criticality was rneas-
sured as a function of the Furfural height as in-
creasing quantities of stainless steel were inserted
and as the solution was diluted. In this manner a
stepwise approach was made to a loading of uniform
LT
0
+-
0.28
0.26
0.24
111
LL
k 0.22
d
w
E
4 0.20
k
z
? 0.18
N
0
X
~ 0.46
Id
3 LL
2 0.14
F
P
8 0.12
.z
0
s 0.40
a
ar
(1.
48
0.08
0.05
concentration which would be critical at the de-
signed linear dimensions of both fuel solution and
Furfural and which would contain the prescribed
mass of stainless steel. These conditions have
not been achieved because the last dilution was
overestimated and a large part of the solution is at
a concentration somewhat lower than required for
criticality, a deficiency compensated for by locating
about 50 tubes of higher concentration fuel in one
peripheral section. The configuration is described
in Table 4.2.
Some neutron-flux measurements have been made
by using effectively thin (3 x lom4 in.) indium foils
ORNL- LR- DWG 301 9
0 04 .
0 5 io 45 20 25 30 35 40
RADIUS (crn)
Fig. 4.4. Radial Fuel Distribution in Suporcritical-Hater Reactor.