The control of nuclear reactors requires computer systems with the highest level of safety, reliability and availability, calling for electronics qualified for very harsh industrial environments and redundant system design. These systems must guarantee the safety of men and the availability of machines while protecting the environment on a daily basis. They are installed in on-board reactors (naval), test, experimental and low-power reactors.

The computing heart in this application is a VMEbus single-board computer in double Eurocard format. It is based on a PowerPC® with 603e core running under the extremely reliable QNX® real-time operating system. The required reliability on the hardware level is guaranteed by having each system consist of three independent single-board computer units, identically configured and built up with the same combination of M-Modules™.

The communication between the units is done via a fiber-optic network, realized with a PMC module plugged on the CPU card. A selection of different M-Modules™ is used for the real-world I/O functions like optically isolated binary wide range inputs or relay outputs. Another M-Module™ extends the 4 COMs on the CPU card by 4 more high-performance serial interfaces that are optically isolated. 3 M-Modules™ can be mounted on the CPU card itself. For the remaining M-Modules™ a customized carrier board supporting 500V isolation voltage has been designed. The complete computer system is qualified for an operation temperature between -40 and +85°C.