What Actually Is Meant by “Proliferation Resistance” in Discussions of Advanced Nuclear Fuel Cycles?

The term “proliferation resistance” is used to denote many different things in the context of nuclear fuel cycles. This range of meanings commonly leads to miscommunication between and within the nuclear fuel cycle and safeguards communities. With the hope of adding clarity to the dialogues, this paper describes some of the definitions that have been and are used (explicitly and implicitly) for “proliferation resistance.” The focus is restricted to fuel cycles involving separations with particular emphasis on the Advanced Fuel Cycle Initiative, and some common fuel cycle paradigms are used to illustrate why imprecise definitions needlessly confuse communication. The evaluation also is limited to international safeguards, where the threat is posed by the State owning the facilities rather than a sub-national group. The authors conclude by urging users of the term “proliferation resistance” to be explicit in defining the threat scenario(s) to which the term is being applied.