Refurbishing of the CERN PS Complex Personnel Protection System

In 2010, the refurbishment of the Personnel Protection System of the CERN Proton Synchrotron (PS) primary beam areas started. This large scale project was motivated by the obsolescence of the existing system and the objective of rationalizing the personnel protection systems across the accelerator complexes at CERN to meet the latest recommendations of the regulatory bodies of the host states. A new generation of access points providing biometric identification, authorization and coactivity clearance, reinforced passage check, and other radioprotection related functionality will allow access to the radiological areas. Using a distributed fail-safe PLC architecture and a diversely redundant logic chain, the cascaded PS Access Safety System guarantees the personnel safety in the 17 machine zones of the PS complex by acting on the important safety elements of each zone and on the adjacent upstream ones. It covers radiological and activated air hazards from circulating beams as well as laser and electrical hazards. This paper summarizes the functionalities provided, the new concepts introduced, and the functional safety methodology followed to deal with the renovation of this 50 year old facility.