Safety problems of NPPs based on boiling water-cooled graphite channel reactors

Specific features and operating criteria of basic control and protection systems, which ensure safe running of the RBMK-1000 LWGR type reactor are discussed. In order to stabilize the power distribution in such reactors a system of local automatic regulators triggered by in-core detectors is provided. Both modes of emergency shutdown after loss-of-coolant and or loss-of-flow accidents and of controlled reduction of power to a safe level after partial failure of the NPPs equipment are considered. The ECCS systen ensures that the core will remain intact even after a hypothetic ''heliotine'' pipe break in the main circulating circuit. The RBMK reactors are concluded to be safe and reliable in operation