ORNL-5388 - the Molten Salt Energy Technologies Web Site

e
A-10
technique is that a module, de'fined as a separation unit consisting of one set of com-
pressors and one set of separation elements, does not as in the classic case, produce only
one separation factor of enrichment in one pass but can produce for a constant separative
work capacity various degrees of enrichment up to a maximum of several times the separation
factor over the element.
Full scale modules of this type are nearing the prototype stage. Recent design
improvements are expected to result in a nominal capacity of 80 to 90 kg SWU/yrll per
separation module.
A valuable feature of a plant based on this process is its very low uranium inven-
tory, which results in a short cascade equilibrium time, of the order of 16 hours for a
commercial plant enriching uranium to 3% 235U.
The theoretical lower limit to the specific energy consumption of the separation
element can be shown to be about 0.30 MW.h/kg SW. The minimum figure observed by the
developers with laboratory separating elements is about 1.80 MW.h/kg SW, based on
adiabatic compression and ignoring all system inefficiencies. This difference is a
measure of the improvement potential expected by the South Africans.
Current and Projected Enrichment Capacity
Most of the known installed enrichment capacity is based upon gaseous diffusion
technology. Only small increments of centrifuge technology are in operation (1 .e. ,
URENCO, Japan and U.S.), and one plant utilizing modified nozzle technology (the South
African Helikon plant) may be operating. Indicative of the status of other isotope
separation methods, all planned additions to the world enrichment capacity are based on
either diffusion, centrifuge or nozzle technology.
The existing worldwide capacity and planned additions to capacity are shown in
Table A-1 by colcntry and technology type. In the table the groups identified as
Eurodif and Coredif are multinational organizations building gaseous diffusion plants
in France.
A.2, New Separation Technologies
In addition to the more developed technologies (gaseous diffusion, gas centri-
fuge, and the Becker nozzle), there are several other separation methods that either
have been utilized in the past or are currently being developed. These technologies
are listed in Table A-2.
L
L
Id
L
E.
P
u
L
b
6'
L