Nonproliferation and fusion power plants
Authors: Hua Michael Y. , Desai Sachin S. , Roma Amy C. , Fulvio Angela Di , Mundie Craig J. , Pozzi Sara A. 
Published: July 2022

The world now appears to be on the brink of realizing commercial fusion. As fusion energy progresses towards near-term commercial deployment, the question arises as to the role of the Treaty on the Non Proliferation of Nuclear Weapons (NPT) with respect to fusion, including whether the nuclear nonproliferation regime includes – or should be extended to include – future fusion plants. The global nuclear nonproliferation regime, solidified in and based on the NPT, is designed to ensure that certain types of radioactive material and technology are used only for peaceful purposes and not nuclear weapons purposes. In that regard, the NPT regime controls and monitors nuclear materials and technology that could be used towards making nuclear weapons. That is, the NPT expressly restricts the transfer of source material (i.e., unenriched uranium and thorium); special fissionable material (i.e., enriched uranium (U-235), uranium-233, and plutonium-239); and equipment that is “especially designed or prepared for processing, use, or production of specialfissionable material.” As spelled out more explicitly in the implementing documents for the NPT– the International Atomic Energy Act (IAEA) safeguards agreements and associated instruments intended to be used with the safeguards agreement – such equipment is limited to nuclear fission-related technology, including fission reactors and the fission nuclear fuel cycle technologies (e.g., enrichment and conversion facilities). Therefore, the plain language of the NPT is limited in scope to source or special fissionable material, and some fission-related facilities. The NPT regulates source material because it can be enriched into special fissionable material; it regulates special fissionable material because it is, or can be enriched to be, weapons-usable material; and it regulates certain specific underlying equipment because such equipment “is especially designed or prepared” to make, use, or further refine special fissionable material. The NPT implementing documents are likewise limited to this same type of material and equipment. In relation to fission, fusion resides at the opposite end of the period table: where fission uses very heavy elements – like uranium and plutonium – to sustain a chain reaction to split atoms andrelease energy, fusion uses the lightest atoms – like hydrogen and helium – to combine (or fuse) into heavier ones and release energy. Fusion cannot sustain a fission-like chain reaction. And because fusion does not use source or special fissionable material, or associated controlled technologies(e.g., a fission reactor or uranium enrichment facility) commercial fusion applications prima facie fall outside the current NPT nonproliferation regime and implementing documents. The question then becomes whether fusion plants should be included within the NPT and associated safeguards framework, or whether the existing global export control framework appears sufficient to control the technology. To answer this requires an analysis of fusion technology and its proliferation risk profile to determine whether it is similar enough in terms of risk considerations to warrant similar treatment under – and therefore amendment of – the NPT. Based on a technical analysis explained herein, and as applied to the existing legal framework of the NPT, this paper concludes that commercial fusion facilities should continue to fall outsidethe NPT. To include fusion would require significant revision and change to the intent of the NPT, and extensive global consensus, which is not an easy task. Nor does it appear to be warranted considering that the same nonproliferation risk associated with traditional nuclear fission just does not exist for fusion. That is, as a general matter, unlike fission technology, fusion technology cannot be directly used in its existing form to support the nuclear fuel cycle for nuclear weapons, as is the subject of the NPT restrictions. Rather, this paper concludes that fusion facilities as they are “especially designed or prepared” have very limited significance to the development of nuclear weapons material for weapons purposes or nuclear weapons themselves. Rather, any potential, malicious misuse of the fusion technology from a nonproliferation perspective would require significant material changes to the underlying technology itself. But that is not to say fusion technology is not controlled to ensure it does not fall into the hands of a bad actor. On the contrary, under international trade laws, the existing export control framework still applies to fusion. This framework restricts the export of a range of technologies for certain end destinations and uses much more broadly than the NPT nonproliferation framework, and extends to other nuclear technologies such as particle accelerators and irradiators, or other facilities tangentially, but not directly related to nonproliferation. Applying – and modifying these approaches as necessary – to develop a usage-based controls regime for fusion can more effectively support the safe deployment of this essential technology, rather than applying the ill-fit, fission-specific nonproliferation regime.