Safety systems in the ITER neutral beam test facility

SPIDER, the experimental device of the ITER Neutral Beam Test Facility (NBTF) devoted to the study of the ion source, has recently started operation. The construction of MITICA, the full-size prototype of the ITER heating neutral beam injector, is in progress. SPIDER and MITICA operation presents many possible hazards including radiation, electrical, explosive gas, laser and fire risks. An integrated approach, referred to as the NBTF Safety System, was chosen to deal globally with all risks for people and environment safety. As many different systems collaborate to guarantee the NBTF safety, a coordinating system, called Central Safety System (CSS), was implemented to supervise safety-relevant systems and provide an effective human interface of the NBTF safety. The CSS is also required to implement directly safety instrumented functions. The requirements of the safety systems derived from the safety risk analysis. The CSS uses the Siemens SIMATIC S7 400FH PLC along with safe input/output remote nodes connected through double ring-topology, redundant Profibus network. Complying with the IEC 61508/61511 standards, the system architecture uses the PROFISafe profile and the human machine interface is based on WinCC Open Architecture. Special provisions are used for communication of safety-related information with the PLC.