Site protection and functional safety for a nuclear experimental area

Security/Safety Nuclear Switzerland

Context and challenges

This client is a top-tier player in nuclear research and fundamental physics. The activities carried out in experimental facilities represent major sources of danger such as ionising radiation, intense magnetic fields, cryogenics, high voltage electricity, anoxia etc.

The complexity and dimensions of experimental areas required special management of access control to protect the personnel.

It was necessary for this client to secure access points to the largest experimental area:

  • Access control to a specific experimentation lab
  • Sub-division of experimental area to ensure the absence of personnel in the area and prevent any risk of intrusion or untimely machine start-up

In this context, the client entrusted Assystem with the integration and commissioning of a Safety Instrumented System (SIS).

Project scope

  • Specification and Design of SIL 3 Safety Instrumented System according to IEC (International Electrotechnical Commission) standard 61508/61511, taking account of requirements from IEC 61513 standard on nuclear safety.
  • Implementation, installation, testing and commissioning of complete system:
    • Siemens S7-317F CPU and 14 ET200M stations
    • Scada WinCC
    • Electro-mechanical actuators: patrol boxes, key switches, instrumented doors, secured relays
    • Diester key safes
    • Cabled console
    • Secure interfaces with external security systems
  • Completion of factory tests using a simulated operating section to exhaustively cover functional scenarios prior to on-site testing
  • Training for operators and maintenance personnel
  • Long-term maintenance operations

All connections and interfaces are subject to surveillance (self-diagnostics) to report technical alarms as soon as an anomaly is detected.

Client benefits

  • Design of custom system, validated and adopted rapidly given the importance attached to the specification phase and the rigorous validation.
  • Minimal modifications once the system was in service through the exhaustiveness of tests carried out (especially via simulations).
  • Integrity of system security preserved and risks for personnel mitigated through system maintenance monitoring by Assystem since its commissioning in 2008 and observance of normative requirements.
  • System now in continuous operation for over 10 years.

in figures


UPS (Uninterruptible Power Supply)


Patrol boxes


I/O (Input/Output)


Instrumented doors

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