ORNL-4191 - the Molten Salt Energy Technologies Web Site

Table 7.1. Design Parameters
-. .... __ ......... ................. .
Reactor power, Mw (thermal)
91
Fuel
Fuel salt flow rate, ft3/sec
Core diameter, ft
Core height, ft
Volume fuel salt in core, ft3
Volume fuel salt in heat exchanger, ft3
Volume fuel salt in piping between rore and heat exchanger, ft3
Fuel cell cross section
,DOWNFLOW CHANNEL
‘UPFLOW CHANNEL
Total graphite surface area exposed to salt, ft2
Mass transfer coefficient to graphite - upflow, ft/hr
Mass transfer coefficient to graphite - downstream, ft/hr
Mean thermal flux, neutrons sec-’ cm-’
Mean fast flux, neutrons sec-‘ crn-’
Thermal neutron cross section for 233U, barns
Fast neutron cross section for 233U, barns
Total core volume - graphite and salt, ft3.
233U concentration in core - homogenized, atoms barn-’
Graphite void available to xenon, 75
13’xe parameters
Decay constant, l/hr
Generation direct from fission, 70
Generation from iodine decay, %
Cross section for MSRR neutron spectrum, barns
-1
cm
5 56
233u
25.0
8
10
83
83
61
3630
0.72
0.66
5 . 0 1014 ~
7.6 x 1014
253
3G.5
503
1.11
10
7.53 x
0.32a
G.38a
9.94 x los
aThe values for the yield of 13’Xe from the fission of 233U are from an old
source and were used in the screening calculations. Recent values of 1.11% for
generation direct from fission and 6.16% for generation from iodine decay as reported
by C. H. Bizham et al. in Trans. Am. Nucl. Soc. 8(1), June 1965, will be user? in the
future.
The xenon stripping mechanism consists in cir-
culating helium bubbles with the fuel salt and then
removing them from the system. These bubbles
are injected at the inlet to the heat exchanger in
the region of the pump. Xenon-135 migrates to the
bubbles by conventional mass transfer, and the
mass transfer coefficient controls the rate of
migration. The circulating bubbles are then
stripped from the salt by a pipeline gas separator
at the heat exchanger outlet. The heat exchanger,
then, is the xenon stripper region of the fuel loop.
The principal parameters to be discussed here
will be:
1. Diffusion coefficient of xenon in graphite.
2. Parameters associated with circulating bubbles.
(a) Mass transfer coefficient to the bubbles.
(b) The surface area of the bubbles.
3. The surface area of graphite exposed to salt in
the core.
In the plots that follow, the diffusion coefficient
of xenon in graphite at 120Q°F with units of ft2/hr