Safeguards as Architectures of Structured Trust:Governance under Conditions of Mobility, Dual Use and Time Pressure

Working Paper The emergence of small modular reactors (SMRs), advanced modular reactors (AMRs) and microreactors does not only introduce new technological options. It fundamentally transforms the structure and distribution of nuclear risk. Traditional nuclear infrastructures concentrated risk in a limited number of fixed, highly regulated sites. Emerging systems distribute risk across mobile, remote and hybrid environments, including military deployments, resource regions and data infrastructure. This shift from concentrated to distributed and mobile risk challenges existing safeguards and non-proliferation frameworks. Verification, access and accountability can no longer be assumed as stable conditions. They become variable, contested and dependent on operational context. As decision environments become more complex while decision windows shrink, the stability of verification and accountability becomes a core governance condition. The central question is therefore not only how to verify nuclear systems, but under which conditions verification remains possible when risk itself becomes mobile and distributed. This paper proposes a working framework in which safeguards are understood as architectures of structured trust. Trust is not treated as a political or subjective category, but as the outcome of built-in, structured verification applied consistently across systems, actors and jurisdictions. Under real-world conditions, including mobility, stress and variable access, trust depends on whether verification remains continuous and whether accountability can be enforced.