Its ability to translate that position into effective action will depend on whether the disposition options that it chooses for its own surplus plutonium take into account the international repercussions of its internal decisions. This report does not examine the economics of this option relative to treating HEU as a waste. Rather, we have pointed out the necessity for examining further options for HEU because, for reasons explained in this report, the option of blending down may not be implemented with the speed necessary to meet growing security concerns. There are no currently feasible solutions that will get rid of these materials for good. Even the exploration of these methods is tied up with unresolved and contentious political questions regarding the future of nuclear arsenals and of nuclear power.
Fissile materials are, in general, necessary for building nuclear explosives.
They are defined as materials whose nuclei release energy when split and which can be split with both slow and fast neutrons. Fissile materials in sufficient quantities, called critical masses, can sustain chain reactions and can therefore be used to fuel nuclear reactors. We will not consider uranium-233 in this report. The title of our report draws upon a passage in the Bible that recognizes the uncertainties that are inherent in the human condition whenever we try to peer into the future. Philosophers have generally assigned certitudes to the province of God.