A division of the Russian state atomic energy corporation Rosatom, specifically Rosatom Automated Control Systems, has completed the delivery of equipment for computerized subsystems of safety function control systems (ESFAS CS) for Units 3 and 4 of the Kudankulam Nuclear Power Plant in Tamil Nadu.
Atomstroyexport acts as the general design engineer and equipment supplier for this project. A total of about 300 units of equipment were manufactured and delivered to the site—four ESFAS CS sets, corresponding to the number of control and instrumentation system tracks for each power unit equipped with VVER-1000 type reactors.
The ESFAS system is designed to monitor the operating parameters of the power unit when deviating from normal conditions. In case of an accident, the system automatically launches safety control and management systems by sending commands to actuators (such as boron injection pumps and other active protection means). This is done to prevent an accident exceeding design tolerances and to bring the reactor unit into a safe state. Additionally, the system ensures controlled reduction of coolant temperature and pressure after reactor shutdown.
To prevent simultaneous failure, the ESFAS components are physically separated and located in different rooms, and they also have autonomous power supply from separate diesel generators.
Specialists who developed ESFAS CS for Units 3 and 4 used the operational experience of the same system on Units 1 and 2 of the Kudankulam NPP, which allowed for the implementation of several optimized solutions. One such solution is the use of non-programmable modules that process signals from sensors without involving microprocessors. This reduces the dependence of safety functions on application software and increases the equipment's resistance to potential common cause failures.
The final handover of the ESFAS CS equipment was another step in equipping the power units with Russian automation, control, and safety systems implemented through industrial cooperation. Following installation at the site, there will be a pre-commissioning testing phase, which includes both offline and integrated system tests.
After all necessary tests are conducted, the systems will be prepared for commissioning and further operation in Units 3 and 4 of the Kudankulam station. The Kudankulam NPP has six power units with VVER-1000 reactors, with a total installed capacity of 6000 MW. The first stage (Units 1 and 2) was commissioned in 2013 and 2017, respectively, while the second stage (Units 3 and 4) is under construction.