Forgive my alliterative title, but Dr. Per Peterson of UC Berkeley is a co-chair of the Generation IV Proliferation Resistance and Physical Protection Working Group. Several months ago on the thorium-forum he posted five specific categories of performance issues/threats that serve as a basis to assess the proliferation resistance of a proposed reactor design. As a preface to further discussion of this subject, I thought it would be a good idea to repost those categories here:

Proliferation threats:

1) Concealed diversion or production of nuclear material in a declared facility. The primary approach to risk reduction involves the application of effective IAEA safeguards. Knowing where materials are is valuable from the perspectives of safety, reliability, and physical protection, so designing a system to facilitate the application of IAEA safeguards is a great idea in any case.

2) Production of material in clandestine facilities. Here the primary methods for risk reduction involve restricting access to sensitive technologies that are difficult to detect when replicated in a clandestine facility (particularly enrichment), application of effective export controls to detect attempts to acquire dual-use technologies, state-level assessments by the IAEA, and effective use of national technical means and intelligence efforts.

3) Breakout. Here the primary methods for risk reduction involve minimizing the attractiveness of materials used in the system, and sustaining a system of positive and negative security assurances (commonly multilateral or bilateral) that reduce the incentives and security concerns that might lead to breakout.

Physical security threats:

4) Theft of nuclear material for use in nuclear explosives. Here the primary risk reduction involves minimizing the attractiveness of materials used in the system, handling them in areas with very low accessibility (e.g., in hot cells), applying effective physical protection measures to the facility, and having the capacity to respond to and mitigate the consequences if theft does occur (not likely to be Gen IV reactors, but instead attractive legacy materials handled in current systems).

5) Radiological sabotage. Here the primary risk involves power reactors, and the primary risk reduction comes from adopting simpified and passive safety systems for reactivity control and decay heat removal, hardening the vital equipment that performs these safety functions, providing defense in depth with backup from active systems, and providing effective physical protection measures for facilities.

“Proliferation Resistance” is a highly ambiguous term, that allows all sorts of expensive, deterministic, prescriptive requirements to be invoked for future nuclear energy systems. As soon as “Proliferation Resistance” is broken down into these 5 categories of security threats, it becomes much easier to discuss specific and effective approaches to assure that the risks posed by these security threats can be made very low.

I look forward to discussing the performance of the LFTR, in several of its potential variants, against each of these categories.