About three kilograms of fresh highly enriched uranium (HEU).
(Source:
Petr Pavlicek/IAEA)
Significant quantity (SQ) is the approximate
amount of nuclear material for which the possibility of
manufacturing a nuclear explosive device cannot be excluded.
Significant quantities take into account unavoidable losses due to
conversion and manufacturing processes and should not be confused
with critical masses. Significant quantities are used in
establishing the quantity component of the IAEA inspection goal.
Significant quantity values currently in use are given in the table
below.
| Material |
SQ |
| Direct use nuclear material |
| Pua |
8 kg Pu |
| 233U |
8 kg 233U |
| HEU (235U > 20%) |
25 kg 235U |
| Indirect use nuclear material |
| U(235U < 20%)b |
75 kg 235U
(or 10 t natural U
or 20 t depleted U) |
| Th |
20 t Th |
aFor Pu containing less than 80%
238Pu.
bIncluding low enriched, natural, and depleted
uranium.
