India Shuts Unit at Country’s Largest Nuclear Power Plant for Maintenance

On August 3, 2025, Unit 1 of the Kudankulam nuclear power plant in Tamil Nadu, India, was shut down for scheduled maintenance, according to a report from the Central Electricity Authority dated August 7. The 1,000-megawatt unit, the largest of its kind in the country, is undergoing a 65-day maintenance period, which may affect electricity supply in southern India.

A senior official from the Tamil Nadu Distribution and Generation Company confirmed the maintenance, noting that the state may need to source additional power from the market if demand increases. The official, who requested anonymity due to the federal oversight of India’s nuclear facilities, said the second 1,000-megawatt unit at Kudankulam continues to operate normally.

The Kerala State Electricity Board Ltd (KSEBL) submitted a petition to the state’s electricity regulator, highlighting concerns about potential peak-hour power shortages in southern states due to the outage. KSEBL noted: "The projected peak-hour deficit of around 600 MW in August 2025 may worsen due to the scheduled refuelling outage of the Kudankulam nuclear power plant." The shutdown has increased reliance on power exchanges, where low supply and high demand from neighboring states have driven up costs.

To address the shortfall, KSEBL secured 300 MW of peak-hour electricity for August, purchasing from Tata Power at 8.75 rupees per unit and Greenko Energies at 9.18 rupees per unit for the 7:00 PM to midnight slot. The state regulator approved the emergency procurement but expressed concerns about the high rates.

The maintenance at Kudankulam, a critical power source, underscores the challenges of balancing supply and demand in southern India. India is working to expand its nuclear capacity, aiming to reach 100 gigawatts by 2047, up from the current 9 gigawatts, to meet growing energy needs.