ORNL-TM-7207 - the Molten Salt Energy Technologies Web Site

WJDEL SECTION FOR
T! i E R M A L_ AN A L.Y SIS
42
Fig. 7. Arrangement of moderator elements in core B,
points (which only exist in the outer core region), heat transfer would
be greatly diminished. The foPPowfng simplifying assumption was macle
(probably conservative) concerning the salt-film heat-transfer coeffi-
cient: within of a contact point, the heat-transfer coefficient is
zero; elsewhere, it is equal to 80% of the value obtained by use. of the
~ittus-~se~ter correlation. 18 TMS assurnption increased the calculated
total temperature rise in the moderator element by -50% over that ob-
tained by using 8OX of the Dittus-B~elter value for the entire surface,
With these boundary conditions, the heat condl~eti~n equatfon in cy-
lindrical finite difference fom was solved in the 30" section at each
axial node (40 nodes total) using the method of successive ~ve~~e%a~ation.
Starting at the core inlet, the temperatures of an interior and an exterior
salt channel are advanced in an axial marching-type solution through the
coreo M ~ P and raaiai k0mogeneoras power profiles gsee Fig. 4) used,
along with the following assumptions, to give salt-channel axial linear
power profiles (Fig. 8) and IbOcal UIode~atOH VOlUElet9Pic power. At a given
location, the vsPumetrie powers in an interior and an exterior channel
were assumed to be the same, and the volumetric power within the graphite
was assumed to be 1% of that in the salt and constant over the 30" sec-
tion, ~eutronic analyses of the previous MSBR design8 provided the basis
c