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

_... ..&/ ; .; with reactor scram may be relatively mild in DNSRs because of the large
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heat capacity and low vapor pressure of the fuel salt which inherently
retains most of the fission-product decay-heat generators. However, loss
of cooling because of blocked core fuel passages at full power could Lead
to some local salt boiling. A full safety analysis of the DMSR has not
been perf~~~~ed because it would require a much more comprehensive design
than is currently available.
Preliminary consideration of the environmental effects of DMSRs sug-
gests that such effects would generally be milder than %or currently oper-
ating nuclear systems. There would be little or WQ routine gaseous and
liquid radioactive effluents, less waste heat rejection, no shipment of
radioaetive spent fuel during the normal plant life, relatively little
solid radioactive waste, and less impact from uranium mining. In con-
trast to these more favorable features, the DMSR at end-of-life wou%d
involve a more complex decommissioning program and a larger solid waste
disposal task. In addition, during operation, the retention of tritium
and the relatively larger inventory of radionuelides may require extra
efforts to avoid possibly unfavorable effects.
In general, the antiproliferation features of the once-through DMSR
appear to be relatively favorable. The entire fissile uranim fnventory
would be fully denatured, and there would be no convenient means of iso-
lating 233Pa for decay to 233~. me fissile plutonium inven-
tory would be small, of POOP quality, and difficult to extract from the
large mass of highly radioactive fuel salt. In addition, no shipments
of spent fuel from the plant would occur except at the end-of-life.
6.2 Alternate BMSR Concepts
Although a DMSR operating on a 30-year, once-through fuel eycfe ap-
pears to have a number of attractive features, the basic concept could
be adapted to a number of alternative fuel cycles. If full-scale, on-
line processing of the fuel salt to remove fission products were adopted,
some likelihood exists that break-even breeding performance could be
achieved. Mowever, even wlthout break-even breedimg, the fuel charge
could be recycled through several generations sf reactor^ to greatly