Development of Dependable Embedded System for Spent Subassembly Storage Bay Transfer Machine of PFBR using Model based Environment

Prototype Fast Breeder Reactor (PFBR), a 500 MWe, sodium cooled, fast breeder reactor is in advanced stage of construction at Kalpakkam, TamilNadu. The different types of subassemblies are handled with different fuel handling machines, inside and outside the reactor vessel. Spent subassembly Storage bay Transfer Machine (SSTM), is one such machine that handles spent fuel subassemblies, blankets & absorbers to store them in storage racks arranged within the storage bay and further shifting to Spent Subassembly Transport Cask. A dedicated embedded system is designed and developed to control SSTM remotely from handling control room. Since the failure of the system affects the safety and availability of the nuclear plant, the control system has to be highly reliable and available. In addition to standard development methodology and life cycle process, a model based environment is also adopted for the development of control logic. Safety Critical Application Development Environment (SCADE) is used to develop, simulate, analyse the model coverage, formally verify the control logic and generate ‘C’ code based on the verified model. The generated code is integrated with the manual code to test on the target and application is executed. Thus, the system was functionally qualified successfully. This paper details the hardware, software development and verification techniques followed for SSTM control system.