Rosatom Completes Supply of Nuclear Safety Control Systems for Kudankulam Units 3 and 4

Russia’s state nuclear energy corporation Rosatom has completed the delivery of advanced reactor safety control systems for Units 3 and 4 of the Kudankulam Nuclear Power Project in Tamil Nadu. The milestone marks further progress in the construction of two additional 1,000 MW nuclear reactors being developed through India–Russia civil nuclear cooperation.

According to Rosatom’s official announcement dated October 20, 2026, its subsidiary Rosatom Automated Control Systems (RASU) completed the supply of equipment for the Engineered Safety Features Actuation System (ESFAS). Approximately 300 equipment items have been manufactured and delivered for the two reactor units.

The systems are designed to monitor critical reactor operating parameters and automatically activate designated safety equipment when abnormal operating conditions arise. Their delivery represents an important stage in equipping the reactors with specialised automation, monitoring and protection infrastructure.

Around 300 Safety System Components Delivered to Kudankulam

Rosatom Automated Control Systems manufactured and supplied approximately 300 equipment items for the safety control systems of Kudankulam Units 3 and 4. The equipment includes four sets of computerised safety control systems for each reactor, corresponding to the four independent safety instrumentation and control channels.

The two reactors use the Russian-designed VVER-1000 pressurised water reactor technology. Each unit has an installed electrical generation capacity of 1,000 MW and incorporates multiple safety systems designed to maintain safe reactor operation under normal and abnormal conditions.

The delivered equipment forms part of the broader automation and control infrastructure required for the reactors. Rosatom’s engineering division, through Atomstroyexport, coordinates the supply of equipment and related engineering activities for the project.

The latest delivery completes an important equipment supply requirement. Installation, integrated testing and commissioning-related activities must still take place before the safety systems can become operational.

How the Engineered Safety Features Actuation System Protects Nuclear Reactors

The Engineered Safety Features Actuation System performs an important protective function in a nuclear power plant. It continuously receives information from instruments monitoring reactor operating conditions, including parameters relevant to temperature, pressure and other safety-critical processes.

When monitored conditions exceed specified limits, the system can automatically issue commands to activate designated reactor safety equipment. These protective actions are designed to prevent abnormal operating conditions from developing into more serious events and to maintain the reactor within established safety requirements.

Rosatom explained that the system can initiate the operation of equipment such as boron injection pumps and other active protection mechanisms. Boron is used in pressurised water reactors to help control nuclear reactivity because it absorbs neutrons involved in sustaining the nuclear chain reaction.

The system also supports controlled reactor cooldown following shutdown. This process involves reducing the temperature and pressure of the reactor coolant in a regulated manner until safe operating conditions are established.

The automation provided by such systems is important because reactor protection must function reliably when rapid protective action is required.

Four Independent Safety Channels Provide Additional Protection

An important feature of the equipment supplied for Kudankulam Units 3 and 4 is the provision of four independent safety control channels for each reactor.

According to Rosatom, the safety system equipment is physically separated and installed in different rooms. The individual channels also receive autonomous electrical power from separate diesel generators.

This arrangement is intended to reduce the possibility that a single equipment failure, localised disturbance or electrical supply problem could disable multiple safety channels simultaneously.

Redundancy and physical separation are established principles of nuclear reactor safety engineering. By providing multiple channels capable of performing designated protection functions, reactor designers aim to improve the reliability and availability of important safety systems.

The configuration supplied to Kudankulam reflects these principles through independent equipment arrangements, physical separation and dedicated backup electrical power.

Rosatom Introduces Non-Programmable Modules to Improve Reliability

The safety control systems for Units 3 and 4 incorporate design improvements informed by operational experience with similar equipment installed at Kudankulam’s first two reactor units.

One important development involves the use of non-programmable modules to process signals received from monitoring instruments. These modules perform designated signal-processing functions without relying on microprocessors or application software.

According to Rosatom, the approach reduces the dependence of certain safety functions on software and improves resistance to potential common-cause failures.

Common-cause failures are particularly important in systems containing multiple redundant channels because a shared technical vulnerability can potentially affect more than one channel.

Using non-programmable processing modules for selected functions provides an additional engineering approach to reducing such vulnerabilities. The systems nevertheless remain subject to detailed installation checks, functional testing and regulatory requirements before entering service.

The improvements demonstrate how experience gained from operating nuclear reactors can contribute to the refinement of equipment used in subsequent units.

Installation and Pre-Commissioning Tests Form the Next Stage

Following the completion of equipment deliveries, the next stage involves installing the safety control systems at the Kudankulam construction site.

Rosatom has stated that installation will be followed by pre-commissioning activities, including independent equipment checks and integrated system testing. These procedures are intended to confirm that the installed systems perform their designated functions and interact correctly with other reactor equipment.

Independent testing examines the performance of individual components and subsystems, while integrated testing evaluates their operation as part of the larger reactor protection infrastructure.

The systems will subsequently undergo further preparations for commissioning and eventual operation as part of Units 3 and 4.

The latest announcement therefore represents the completion of equipment supply rather than the completion of reactor construction or the commissioning of the safety systems.

Kudankulam Nuclear Power Project to Have 6,000 MW Capacity

The Kudankulam Nuclear Power Project, located in Tirunelveli district of Tamil Nadu, is one of India’s major civil nuclear energy developments undertaken through international cooperation.

The project envisages six VVER-1000 pressurised water reactor units, each with an installed electrical capacity of 1,000 MW. The complete development is designed to provide 6,000 MW of nuclear generating capacity.

Units 1 and 2 are already operational, while Units 3 and 4 remain under construction. The Atomic Energy Regulatory Board has also granted permission for major equipment erection at Units 5 and 6, following its assessment of design safety requirements and construction progress.

The expansion will strengthen India’s nuclear power generation infrastructure and contribute to the country’s efforts to increase the availability of reliable, low-carbon electricity.

Nuclear power stations can provide electricity independently of daily variations in sunlight and wind conditions, making them an important component of a diversified power generation system.

The additional Kudankulam units form part of India’s long-term programme to expand nuclear generating capacity while maintaining established regulatory and operational safety requirements.

India–Russia Cooperation Advances Nuclear Energy Infrastructure

Kudankulam represents a longstanding partnership between India and Russia in civilian nuclear energy.

The Nuclear Power Corporation of India Limited (NPCIL) is responsible for developing and operating the project, while Russian organisations provide reactor technology, engineering services and specialised equipment under the bilateral cooperation framework.

Rosatom’s engineering division plays an important role in coordinating the design and equipment supply activities. The latest delivery involves cooperation between Atomstroyexport, Atomenergoproekt, Atomtekhenergo, Rosatom Automated Control Systems and associated equipment manufacturers.

The arrangement brings together expertise in reactor engineering, instrumentation, electrical systems and nuclear safety technology.

Experience gained from the operation of Kudankulam’s first two units has also informed the design and implementation of equipment for the subsequent reactors.

The delivery of the new safety control systems demonstrates continued industrial and technical cooperation between Indian and Russian nuclear organisations.

Advanced Safety Infrastructure Supports India’s Nuclear Power Expansion

The development of additional nuclear reactors requires extensive safety engineering, specialised equipment and rigorous verification procedures.

Modern nuclear power plants incorporate multiple layers of protection, including reactor shutdown systems, emergency cooling arrangements, backup power supplies and automated monitoring equipment. These systems are designed to prevent accidents, control abnormal conditions and maintain essential safety functions.

The safety control equipment delivered for Kudankulam Units 3 and 4 forms part of this integrated protective infrastructure.

The use of independent safety channels, physically separated equipment and dedicated power supplies reflects the importance placed on reliability and redundancy in nuclear reactor engineering.

As the project progresses through construction and commissioning, these systems will undergo further technical assessment to establish their readiness for operation.

Kudankulam Moves Forward with Additional Reactor Safety Systems

Rosatom’s completion of safety control equipment deliveries represents another milestone in the development of Kudankulam’s third and fourth nuclear power units.

The supply of approximately 300 equipment items, including four independent safety control sets for each reactor, strengthens the project’s progress towards installing its specialised automation and protection infrastructure.

The incorporation of design improvements based on experience with the first two units also reflects the continuing development of reactor safety engineering within the India–Russia nuclear partnership.

With installation and pre-commissioning testing forming the next stages, Kudankulam continues to advance towards its planned expansion into a six-unit nuclear power complex.

The project remains an important component of India’s efforts to expand dependable electricity generation, strengthen energy security and develop a diversified low-carbon energy system through sustained technological cooperation.

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References

1. Rosatom State Atomic Energy Corporation — 20 October 2026. Rosatom Completes Delivery of Safety Control Systems for Kudankulam Nuclear Power Plant Units 3 and 4. Official press release issued through Atom Media, documenting the delivery of approximately 300 equipment items, system configuration, protection functions and planned commissioning activities.
2. Atomic Energy Regulatory Board, Government of India — 1 May 2026. AERB Issues Permission for Major Equipment Erection at Units 5 and 6 of Kudankulam Nuclear Power Project. Press Information Bureau, Release ID: 2257371. The release describes the overall six-unit project and confirms the construction status of Units 3 and 4.
3. Nuclear Power Corporation of India Limited. Kudankulam Nuclear Power Project. Official project information concerning reactor technology, installed capacity and plant development.
4. Department of Atomic Energy, Government of India. Official information on India’s nuclear power development programme and civil nuclear cooperation.

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