Nuclear Proliferation TechnologyTrends Analysis - International ...

PNNL -14480
1) There is a very low efficiency in feed utilization, due to the tendency of
ionized uranium vapor to deposit on all available surfaces inside the vacuum
chamber. Only ten to fifteen percent of the feed material is actually ionized,
meaning that the cut (the ratio of product flow to feed flow) is below .01 for
low enriched feed.
2) Control of the ion beam current is important for various physical reasons. As
the collection rate is directly proportional to the ion beam strength, the amount
of material deposited is limited.
3) To maximize the amount of material arriving at the collectors, the beams must
be focused by adjusting the magnetic fields.
Table 10 lists important technologies and related technical issues.
Technology
Ion Source
Ion Collectors
Vacuum Housings
Magnet Pole Pieces
High-voltage Power Supplies
DC Magnet Power Supplies
Vacuum Pumps
Uranium Recovery
Technical Issues
Obtain high U+ beam currents from source, control expansion of beam, properly
focus ion beam on collector slits, heater life, insulator breakdown, damage to
source components due to high energy ions
Retain and measure collected uranium, retain shape over wide temperature range,
resist sputtering, conduct heat, permit recovery of deposited uranium.
Leakage rate; open and close with minimum downtime
Maintain low magnetic field ripple
Maintain stable voltage
Maintain stable current
Maintain high vacuum in large evacuated region
Substantial chemical processing facility required, labor intensive
Table 10 Technology and technical issues involved with EMIS
3.3.2.2 Changes/improvements in technology
In 1946, Swedish scientists developed an improved calutron design. By varying
magnetic field focus and having the ion beam go through a 255 0 arc, the separation power
could be increased by a factor of 1.5, and higher intensity ion currents could be used.
This type of calutron, called a 255 0 machine, has a significantly higher production rate
than the 180 0 machines 70 .
Efforts to increase the performance of magnetic spectrometers have led to significant
improvements in magnet design, which can increase the ability to focus the ion beams
and increase production efficiency accordingly.
3.3.3 Countries that have used/attempted to use technology
A number of countries have acquired EMIS technology. Table 11 lists those with
significant programs, but only three have actively tried to use EMIS to acquire HEU.
The others acquired single or small numbers of units and used them for other purposes.
70 Iraq’s calutrons: Electromagnetic isotope separation, beam technology, and nuclear weapon proliferation, Andre Gsponer and Jean-
Pierre Hurni, ISRI-95-03, 10/19/95
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