There are several isotopes that the IAEA considers Special
Fissionable Material:
- plutonium-239
- uranium-233
- uranium enriched in the isotopes 235 or 233
- any material containing one or more of the foregoing
- such other fissionable material as the Board of Governors shall
from time to time determine
However, the term 'special fissionable material' does not
include source material (taken from INFCIRC 153* & 540*).
