Table 1: Estimated Civil Plutonium Inventory (in tonnes)(a)

(a) Uncertainties in the amount of plutonium produced are about 10 percent. The uncertainty in the amount of unirradiated plutonium should be less than five percent, because most of these values are declared officially, and stated to be accurate to within 100 kilograms. However, the declarations do not state whether plutonium 241 decay has been accounted for, which could be significant in the case of old separated plutonium.
(b) See Table A2, values rounded.
(c) The values for plutonium in irradiated (spent) fuel have not been rounded, in order to maintain consistency with the quantities of separated plutonium. The uncertainty in the irradiated values is at least 10 percent, and thus they are more approximate than they appear.