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

77
4
will apparently be necessary (see Table .l7Is assuming the fuel volume
CfpaRgeS from these additions Other Causes do T3Ot require 3?@lTkOVa% Sf
any fuel to storage, Such additions, which are made over- the 30-year
lifetime, would comprise some 38,190 kg (96,332 moles) of UP4 added at
an average of 1,840 kg (3,320 rneles)/year.
~uring operation, 22 many on-stream additions S% fissionable natertal
as molten ~ L ~ were ~ umade P ~ to the MSRE, and this method of addition can
obviously be used as a clean, convenient way to add the uranium to a DMSW,
Using this method of addition would require use of 2.89 x IO5 moles (7.514
kg) of ?LiF containing 2013 kg of 7Li. This represents about 6.8% of the
ki in the original fuel inventory and would result in appreciable vo~upne
increase (especially if BeF2 were added proportionally) in the fuel. t
During the course of reactor ope ratio^, removing some fuel tu storage
within the reactor complex would probably be necessary if this addition
procedure were used.
Developing and demonstrating methods of addition of solid W4 (or
proper mixtures of UF4 plus UF3) should be possible.
herently more complex (and radioactively dirty), and stating which sf the
options would be preferred is not presently possible.
These will be in-
Mafntafnfng the desired UF3/UF4 ratio. Operation of the PlSREl 9s22
demonstrated that in situ production of m3 could be accomplished readily
and conveniently by permitting the circulating fuel to react in the pump
bowl with a rod of metallic berylPim suspended in a cage of Rastelloy-Ne
This technique could be adapted for use in a DMSR; bery%lim reduction
would be desirable if the fissionable and fertile uranium additions are
to be made as 7 ~ 1 ~ ~ 1 7 ~ ~
+
as. Additions would be made as depleted material or as material contain-
ing not more than 28% of 235U in 23*U; the materials would be added as
mixed fluorides or possibly as W4 plus LF3.
evelo loping and demonstrating a method of addition of a high-uranium-
content liquid with considerably less LiF than L I ~ U F are ~ almost certddy
goss Bbl e e
'In that event, adding BeF2 will be necessary to preserve the LfF/
BeFz ratio in the fuel at approximately its initial value.