Computerized assistance for designers in validating automatic systems for the N4 series

Because of the ever-increasing safety requirements for NPPs plants the automatic devices of control systems must be subjected to the most thorough tests before being installed in plants. For N4 series plants, Electricite de France has set up an extensively computerized system for validating automatic systems with a view to: (1) Easily generating a file for the safety authorities and guaranteeing its updating in the light of changes; (2) Reducing routine and risky handling in design offices; (3) Saving time during on-site tests. The system is based on the 'P20 tester' consisting of a generic automatic device and a simulation environment controlled by a computer. This environment can at the same time simulate the process, inform the test team of the behaviour of the automatic system and edit reports. The use of the validation system for 18 months has shown a real improvement in the quality of the files obtained. (author). 3 figs