Reactivity and power control

Solid absorber rods are employed to control the reactivity and, thus, the reactor power. The control rods travel on hangers in special channels cooled by water from a separate circuit. The control rods are suspended by the steel strips of drive mechanisms mounted on the channel cappings. The absorber rods fall into several functional groups. 

All these functions are performed by an integrated monitoring, control and protection system (CPS) designed in compliance with the requirements specified by the national regulatory authorities (see, for example. Ref. [5]). The system has a two suite arrangement, with either of the two suites being capable of carrying out all of the system s functions. The system was introduced at Kursk-1 in 2002 and will be fitted to all RBMK plants. 

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The reactivity and power control rod system consists of two identical clusters. Each control rod unit consists of an array of tubes containing B4C to provide a gravity-driven rod drop and a powered drive-in. Gas expansion modules (OEMs) located at the periphery of the active core are passive reactivity feedback assemblies that insert negative reactivity into the core during the loss of flow events. 

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