ORNL-2106 - the Molten Salt Energy Technologies Web Site

ANP PROJECT PROGRESS REPORT
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Comparing this with the calculations for the ab
sorptions in the CFRMR reflector (this includes
beryllium and sodium) operating at CFRMR tem-
perature it can be seen that the absorptions in the
SMC are low. By reducing the water volume in the
coreof the SMC with aluminum spacers (and thereby
reducing the moderation in the core)the absorptions
of neutrons in the beryllium can be increased. With
75% aluminum and 25% water in the spaces, the
tails of the absorption curves are in good agree-
ment. The shape of the curve for the region near
the core-reflector interface does not match as well
as the rest of the curve, but it may be lowered by
adding the water necessary for cooling and ad-
justing the amount of aluminum simulating the
sodium. In this manner the curves can be matched
throughout. Both curves are normalized to one
fission per cubic centimeter in the core region.
Power Distribution
Some effort has been made to match the power
distribution in the core of the CFRMR with that in
the SMC for various percentages of water in the
core (Fig. 5.4.3). Since a difference between the
CFRMR and the SMC with 75% aluminum and 25%
water was noted, some effort was made to bring
these into better agreement. A slightly different
core (100 fuel plates rather than 200) was divided
into five regions to determine the variation that
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ONFIGURATION
ONFIGURATION
ONFIGURATION
ONFIGURATION
WEEN FUEL PLATES
2 - 4.6
LL
I-
4.2
LT w
b 0.8
0
a
0.4
0
42 44 46 48 20 22 24 26
SPACE POINTS IN CORE
28 30 32 34
Fig. 5.4.3. Comparison ef Power Distribution in
Core of CFRMR for Various
Percentages of W?
282 . ..
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\OO-FUEL-PLATE CORE WITH SPACES
BETWEEN FUEL PLATES FILLED WITH
?5% p0--75%$1. j i j
CONFIGURATION 273: RATIO OF MASSES OF
(6 48 20 22 24 26 28 30 32 34 36 38
SPACE POINTS H CORE
Fig. 5.4.4. Effect on SMC Power Distribution
of Varying the UO,
Core.
Mass in Five Regions of the
Gamma-Ray Sources
Another calculation is being carried out at Pratt
& Whitney to determine the importance of each
region as a gamma-ray source. The reactor is being
divided into shells and the gamma-ray intensity
from sources in each shell is being determined in
a line-of-sight attenuation calculation. This is
being done both for the CFRMR and the SMC as a
basis of comparison of the two reactors.
The remaining region of importance that requires
some further work is the heat exchanger. As pre-
viously mentioned the source from the circulation
of the fuel is not present. Previous LTSF data'
indicate that the gamma-ray source resulting from
circulation of the fuel contributes approximately
30% of the gamma-ray dose rate outside the reactor
shield. It is expected that further analysis of the
'H. Woodsum, ANP Quar. Prog. Rep. March 10, 1956,
ORNL-2061, p 237.
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