A cache of nearly 19,000 files linked to the Kudankulam Nuclear Power Plant has surfaced on the dark web after ransomware group World Leaks claimed to have stolen data from Reliance Group, one of the contractors involved in the project, according to Reuters.
The leaked files include blueprints of parts of the plant's facilities, supplier information, inspection records, equipment reviews, and insurance documents covering the period from 2016 to mid-2025.
Their authenticity has not been verified.
Reliance Group told Reuters that there had been a partial data breach involving information stored on a server hosted by third-party data centre provider Yotta. The company said the incident had been reported to the government but did not specify what data had been compromised.
Yotta said it detected suspicious activity on Reliance Infrastructure's server on May 29 and immediately shut it down, preventing what it described as a suspected ransomware attack. However, the company said Reliance later informed it that external threat actors had claimed to possess stolen data. Yotta said it has not been able to verify those claims but has shared its technical findings with Reliance and is assisting in the investigation.
According to Reuters, the Nuclear Power Corporation of India (NPCIL) is coordinating with Reliance on the matter, while the Indian Computer Emergency Response Team (CERT-In) is examining the alleged breach.
The report said the leaked documents do not relate to the reactors' core systems supplied by Russia's Rosatom. However, they reportedly include layouts of ventilation and cooling systems, supplier lists, and a common control room floor plan.
Nickolas Roth, senior director at the Nuclear Threat Initiative, told Reuters that the files could reveal who has access to the project and which systems that access reaches, potentially posing a security risk.
Kudankulam is India's largest nuclear power station and forms a key part of the country's plans to expand nuclear energy capacity.
Reliance Infrastructure was awarded the contract in 2018 to develop infrastructure for Units 3 and 4, which are under construction.