India’s Oldest Nuclear Reactors Resume Operations After Major Modernisation

India’s nuclear energy sector has achieved a significant milestone with the return of the country’s oldest nuclear reactors to the national power grid following an extensive refurbishment and safety upgrade programme. The two reactors, located at the Tarapur Atomic Power Station (TAPS) in Maharashtra, have resumed electricity generation after remaining offline for several years to undergo comprehensive modernisation.

The reactors, known as TAPS-1 and TAPS-2, were originally commissioned in 1969 and are among the oldest operational nuclear power units in the world. Each unit has an installed capacity of 160 megawatts electric (MWe) and has played a key role in India’s civilian nuclear energy programme for more than five decades.

Following the completion of refurbishment activities, TAPS-1 resumed operations late last year, while TAPS-2 recently received regulatory approval to continue functioning for another decade. The two units are now supplying electricity to the national grid, strengthening India’s clean energy capacity at a time when demand for reliable low-carbon power continues to rise.

The modernisation programme involved extensive upgrades to critical reactor systems and safety infrastructure. Engineers replaced key reactor coolant piping components with advanced corrosion-resistant materials designed to improve long-term reliability and operational safety. Detailed inspections and assessments of major reactor components were also carried out to evaluate ageing-related factors and determine the reactors’ remaining operational life.

Regulatory authorities concluded that both units could continue operating safely with routine maintenance and monitoring measures. The successful completion of the life-extension programme demonstrates India’s expertise in managing and modernising ageing nuclear infrastructure while maintaining strict safety standards.

For decades, the Tarapur reactors have contributed significantly to the country’s energy security by supplying dependable, low-carbon electricity. Their return to service is expected to support India’s broader efforts to expand clean energy generation and reduce dependence on fossil fuels.

The development comes amid continued progress in India’s nuclear power expansion programme. At the Kudankulam Nuclear Power Plant in Tamil Nadu, construction activities are advancing on several new reactors. Recently, a major milestone was achieved with the installation of the reactor pressure vessel for the plant’s fifth unit, a crucial component that houses the nuclear reactor core.

The Kudankulam complex, one of India’s largest nuclear power projects, consists of six reactors with a combined capacity of 6,000 MWe. While the first two units are already operational, additional reactors are at various stages of construction and commissioning.

Tarapur itself remains a key hub for India’s nuclear ambitions. In addition to the refurbished units, the site operates two indigenous 540 MWe pressurised heavy water reactors and has been identified as a potential location for future small modular reactor projects. These next-generation reactors are expected to play an important role in meeting India’s long-term energy requirements through flexible and low-carbon power generation.

The revival of TAPS-1 and TAPS-2 highlights the country’s growing technical capabilities in nuclear engineering and reinforces the role of nuclear energy in supporting India’s transition toward a cleaner and more secure energy future.

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