By Venkatachari Jagannathan
Russia’s integrated nuclear power major Rosatom has completed the supply of equipment for engineered safety features actuation system computerised subsystems (ESFAS CS) for the upcoming 3 and 4, 1,000 MW atomic power plants in Tamil Nadu’s Kudankulam.
How the engineered safety system works
ESFAS is the system which monitors the process parameters of a power unit when there is a deviation from normal operation conditions.
In case of an accident, the system automatically initiates the start of safety instrumentation and control systems and sends commands to actuators (boron injection pumps and other active protection means) in order to prevent a beyond-design-basis accident and bring the reactor plant to a safe state, Rosatom said.
The system also ensures reactor cooldown, which is a controlled decrease of coolant temperature and pressure down to safe values after the shutdown.
About 300 equipment items delivered
Rosatom Automated Control Systems JSC (RASU JSC, the Instrumentation & Control and Electrical Engineering Division of Rosatom) completed the supply of equipment for engineered safety features actuation system computerized subsystems (ESFAS CS) for Units 3 and 4 of Kudankulam NPP in Tamil Nadu state, India.
According to Rosatom, a total of about 300 items of equipment were manufactured and delivered to the plant – four sets of ESFAS CS, in accordance with the number of Safety Instrumentation and Control trains, per each power unit featuring VVER-1000 reactors.
To avoid simultaneous failure, they are located in different rooms, and have autonomous power supply from separate diesel generators.
Design improvements based on operating experience
Specialists developing the ESFAS CS for Units 3 and 4 relied on the operating experience of the Units 1 and 2 at Kudankulam. This allowed them to implement several optimized solutions, said Rosatom.
One such solution is the application of non-programmable modules that process signals from sensors without using microprocessors. This helps to reduce the dependence of safety functions on application software and increases the resistance of equipment to potential common cause failures.
Testing and commissioning ahead
Rosatom said the installation of the supplied systems on the site will be followed by the pre-commissioning stage, which includes the off-line and integrated tests of the systems.
Following the tests, the systems will be prepared for commissioning and further operation at Units 3 and 4 in Kudankulam.
Kudankulam nuclear project targets 6,000 MW capacity
The Kudankulam project features six power units with VVER-1000 reactors, with the total installed capacity of 6,000 MW. The developer and technical customer of the facility is the Nuclear Power Corporation of India Ltd.
The general designer and the supplier of equipment is Atomstroyexport JSC (part of the Engineering Division of Rosatom State Corporation). The first phase (Units 1 and 2) was commissioned in 2013 and 2017, respectively. The second phase (Units 3 and 4) is under construction.
The Unit 3 is expected to go on stream in 2027.
(Venkatachari Jagannathan can be reached at venkatacharijagannathan@gmail.com)