The definitions (GenlV International Forum, 2011b) of PR and PP that apply to most nuclear energy systems also apply to small modular reactors (SMRs). They are as follows.

• Proliferation resistance is that characteristic of an SMR that impedes the diversion or undeclared production of nuclear material or misuse of technology by the host state seeking to acquire nuclear weapons or other nuclear explosive devices.

• Physical protection (robustness) is that characteristic of an SMR that impedes the theft of materials suitable for nuclear explosives or radiation dispersal devices (RDDs) and the sabotage of facilities and transportation by sub-national entities and other non-host state adversaries.

Figure 9.1 illustrates the methodological approach at its most basic. For a given system, analysts define a set of challenges, analyze system response to these challenges, and assess outcomes.

The challenges to the SMR are the threats posed by potential proliferant states and by sub-national adversaries. The technical and institutional characteristics of

Handbook of Small Modular Nuclear Reactors. http://dx. doi. Org/10.1533/9780857098535.2.219

Challenges—- ► System response —— ► Outcomes

Threats PR&PP Assessment

Figure 9.1 Basic framework for the PR&PP evaluation methodology.

the SMR systems are used to evaluate the response of the system and determine its resistance to proliferation threats and robustness against sabotage and terrorism threats. The outcomes of the system response are expressed in terms of PR&PP

measures and assessed.

The evaluation methodology assumes that an SMR has been at least conceptualized or designed, including both the intrinsic and extrinsic protective features of the system. Intrinsic features include the physical and engineering aspects of the system; extrinsic features include institutional aspects such as safeguards and external barriers. A major thrust of the PR&PP evaluation is to elucidate the interactions between the intrinsic and the extrinsic features, study their interplay, and then guide the path toward an optimized design.

The structure for the PR&PP evaluation can be applied to the entire fuel cycle or to specific elements of the chosen fuel cycle (reactor, front-end, or back-end of the particular fuel cycle under consideration). The methodology is organized as a progressive approach to allow evaluations to become more detailed and more representative as system design progresses. PR&PP evaluations should be performed at the earliest stages of design when flow diagrams are first developed in order to systematically integrate proliferation resistance and physical protection robustness into the designs of SMRs along with the other possible high-level technology goals such as safety and reliability, and economics. This approach provides early, useful feedback to designers, program policy makers, and external stakeholders from basic process selection (e. g., recycling process and type of fuel), to detailed layout of equipment and structures, to facility demonstration testing.