Proliferation Aspects of Plutonium Recycling

How serious are the proliferation risks of plutonium holdings, whether separated or still in spent fuel? Should the concern be the same for all mixtures of plutonium coming out of different reactor types and for different degrees of nuclear burnup? Should there be different categories of plutonium for verification purposes, as is the case for enriched uranium? This paper reviews the issue of plutonium utilization in nuclear weapons and explosive devices in the context of an effective and efficient verification of nuclear materials by regional and international organizations. Plutonium recycling offers substantial benefits in an energy perspective of sustainable development, while contributing to nonproliferation through the elimination of the residual risks associated with plutonium. Before recycling, reactor-grade plutonium from light-water reactors does not lend itself easily to the assembly of explosive nuclear devices; thereafter, practically not at all. Verification systems for material security and nonproliferation should therefore adopt several categories of plutonium covering various isotopic mixtures associated with different fuel types, in order to better reflect the risks and to better focus their verification activities. The author proposes the adoption of three categories of plutonium.