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

.. . ... . . . . . . .. . .
"W 3. The reference system without protactinium isolation would have no
99
means for removing fission-product zirconium, which would then reach
undesirably high chemical concentrations.
However, the reference process could be modified to meet the requirements
of the BMSR concept. A modified process (described in Ref. 91, in addi-
tion to providing the required fission-product removal, t~ould offer other
advantages
1. The total pButoniew inventory would be limited because the plutonium
would eventually be consued at its production rate in the reactor.
2. The reactor would serve as its o m "incinerator" for transpluton8m
actinides, which would be co~~tinuou~ly recycled in the fuel.
3. Neither the protactinium nor the plutonium would ever be isolated frm
all other hfghly radioactive species.
This modified processing concept would use all the basic unit operations
proposed for the MSBR system lira essentially the same sequence. However,
add8tional, though similar, process steps would be required to remove
zirconium on a reasonable time scale, and these are included in the con-
ceptual flow sheet. Some removal sf neptunium also might be desirable to
avoid the long-term poisoning effects of a37Np and 238Pu; this probably
could be included without adding significantly to the complexity of the
processing facility.
With full-scale fission-product removal and break-even breeding the
fuel in a DMSR could be used indefinitely. That is, at the end-sf-life of
one reactor plant, the fuel salt could be transferred to a new plant and
used without any significant intermediate treatment. During the life of
2HU
any given plant, adding thorium as the principal fertile material and
to maintain compliance with denaturing requirements would be necessary,
but no fissile additions would be required.
Other routine removals sf
fuel-carrier salt (Lip + BeF2 4- ThFb) and additions of ReFz and ThFt+"
would be required to maintain the desired chemical composition of the
salt. The removed carrier salt could be disposed of (after conversion
to a suitable form) or chemically processed for recycle into other MSRs.
Lithium fluoride would be formed continuously in the salt from the
ji
lithium used in the redustivg-extPaction/meta%-tpansfep steps.