NSS-17 + NSS-42-G require facility computer security architecture organised by Computer Security Zones (CSZs) implementing IAEA zone model. Zones correspond to Computer Security Levels (CSL 1 to CSL 5) with stricter security at higher levels: CSL 1 zones (Safety + Security critical) air-gapped or one-way data flow only + most stringent controls + smallest equipment count + highest assurance; CSL 2 zones (Important to safety / security) limited interconnect with strict boundary + monitoring; CSL 3-4 zones (Operational + business) progressively less restrictive; CSL 5 zones (Untrusted administrative + internet-connected). Conduits between zones use industrial firewalls + data diodes (unidirectional gateways) + DMZ patterns + jump hosts + bastion + protocol breaks + content inspection. Direct connections between Untrusted (CSL 5) and Safety/Security Critical (CSL 1) zones strictly prohibited. Defence in Depth: multiple independent layers of protection per zone (perimeter + network + host + application + data); compensating controls if single layer fails; no single point of failure for critical security functions; assume breach mindset for resilience. Architecture documentation: zone + conduit diagram + boundary devices + access paths + remote support entries + wireless + external interfaces (satellite + leased line + IT integration). Coordinates with IEC 62443-3-3 system requirements + IEC 62645 nuclear-specific industrial cyber + NIST SP 800-82 ICS. IAEA NSS-17 + Zones + CSL + Defence in Depth + Boundary + Conduit applies.
This control maps to 213 controls across 122 other frameworks. If you already hold one of them, the evidence you collected for it is the starting point here rather than new work.
Every mapping shown was judged rather than inferred from wording similarity, and the ones that failed review are published too. See the coverage reports and what was rejected.
The graph holds this control, the 213 it maps to, and the evidence behind each claim, over MCP and REST.