A report on the review and formal analysis of the SRS personnel safety system

CLRC Daresbury Laboratory operates the SRS light source, which consists of a linac, booster synchrotron, storage ring and 41 experimental stations. Protection of personnel from radiation and the hazards associated with the accelerators and photon beamlines is ensured through a dedicated personnel safety (PS) system. The design of the PS interlock hardware was produced over 20 years ago, and has been implemented using two generations of technology. The PS system has recently been reviewed due to changes in legislation and in preparation for future accelerator projects. This review included a formal analysis of part of the system using the technique of fault tree analysis to examine likely failure modes and system integrity. The analysis takes into account both hardware and human factors. This paper briefly presents the SRS PS system and discusses the outcome of the recent review and analysis.