Reactor Safety Channel System with on-Line Testing Capability

The LPTR (Livermore Pool Type Reactor) safety system had several undesirable features in the original equipment design (vintage 1956). A single trip bus, electron tube construction, and trip failure in the event of a shorted actuator magnet, are but some of the original equipment problems. The continued use of this equipment resulted in high maintenance costs, excessive actuator magnet replacement, difficult set-up procedures for the operations staff, and the requirement that the reactor be shut down to make safety level trip tests. The design approach used to solve these problems was to float the actuator power sources, use optical isolators for system interconnections, make use of multiple trip buses, and to provide simple test procedures. The resulting system incorporating the above techniques achieves a high level of channel integrity and reliability.