The RCS (Figure 1) in general consists of Rods Position Indication System / Subsystem (RPIS) and Rods Drives Control System / Subsystem (RDCS) with control logic processing equipment power supply subsystem and also can include its own Rod Drives Electric Power Supply Subsystem (RDEPSS) made by RPC Radiy (or any other type of RDEPSS).
Figure 1. Rod Control System
RPIS can indicate all reactor control and safety rods position operation parameters and real rods position. RDCS performs all Rod Drives control functions and include Trip Portion (set of the Rod Drives power supply breakers).
- uninterrupted electric power supply of Rod Drives in normal operation mode,
- switching off the Rod Drives electric power supply by Emergency Protection (EP) signals in case of normal operation failure which requires placing the reactor into a subcritical state.
RCS can have 2 or 3 redundant channels depending on the design basis of the nuclear reactor, and it can implement a voting logic of 1oo2 or 2oo3. Generic architecture of RCS configuration in 1oo2 voting logic version for PWR Unit is shown in Figure 2.
Figure 2. Generic architecture of RCS configuration in 1oo2 voting logic version for PWR Unit
In 2012, the first full set of RCS has been successfully put in operation in the Unit 1 of the South-Ukraine NPP with VVER-1000 PWR-type reactor.