ORNL-5388 - the Molten Salt Energy Technologies Web Site

L
1
L
u
without benefit of U.S. experience.
overriding criterion and could be sacrificed in favor of a more moderate level of
technology.
centrifuge designs to guide mechanically competent engineers with access to adequate
facilities.
technology than prototype construction.
7-5
For a military program, economics would not be an
Moreover, the open literature contains sufficient information concerning the
Replication of an economic design would require a somewhat higher level of
The following particular points regarding the enrichment of denatured 233U fuel
should be noted:
Because of the lower mass of 233U, separating 23% from 238U would require only 9/25
of the effort required to separate 235U from 238U, assuming equal feed enrichments.
Since the fast critical mass of 23% is less than that of 235U, less enrichment
capacity would be required to produce a 23% weapon from 233U/238U feed than would
be required to produce a 235U weapon from 235Uf238U feed, again assuming equal
enrichments of the feed material.
The higher the enrichment of the source material, the less separative work that would
have to be done to upgrade the material to 90% enrichment.
natural uranium to a 10% level consumes 90% of the separative work required to
achieve a 90% level. It is to be noted that the enrichment of denatured 23% fuel
is approximately 12%, whereas the enrichment of currently used LWR 235U fuel is
around 3-4%.
For example, enriching
With respect to items (2) and (3), a rough comparison can be made of the feed
requirements and the number of centrifuges that would be necessary to produce 90% enriched
material from various fuels in one year (normalized to 1 kg of product):
Number of Centrifuges Required
- Fuel
Feed Required
(kg)
0.3 kg SWUfyr
Capacity
5 kg SWUfyr
Capacity
12% 233u 8 55 3
20% 2351) 5 50 3
3.2% 235U 30 292 17
Natural Uranium 178 779 46
The above values do not consider measures to eliminate the 232U contamination and they
assume that a reasonable tails assay will be maintained (%0.2% 235U).
assay were acceptable, the number of centrifuges could be reduced but the feed material
required would be increased.
If a higher tails
One year, of course, is a long time when compared to a period of weeks that would
be needed to obtain approximately 10 kg of plutonium by chemically reprocessing two to
three spent LWR-LEU fuel elements.
It would be possible to speed up the process time for
the centrifuge method either by increasing the individual machine capacity, by adding
additional centrifuges, or by operating at a higher tails assay.
Increasing the capacity