"This is to clarify Kudankulam Nuclear Power Project (KNPP) and other Indian Nuclear Power Plants Control Systems are standalone and not connected to outside cyber network and Internet," R. Ramdoss, Training Superintendent & Information Officer, said in a statement.
"Any Cyber attack on the Nuclear Power Plant Control System is not possible," he added.
According to him, the KNPP units 1 and 2 are operating at 1,000 MW and 600 MW respectively without any operation or safety concerns.
The KNPP has two nuclear power units of 1,000 MW capacity each.
The issue came up when an Indian twitter user Pukhraj Singh tweeted: "So, it's public now. Domain controller-level access at Kudankulam Nuclear Power Plant... The government was notified way back. Extremely mission-critical targets were hit."
Singh later tweeted: "Seeing KKNPP's press release, I would like to add that I notified Lt Gen Rajesh Pant (National Cyber Security Coordinator) on September 4. Follow-up emails were exchanged... acknowledging the issue. I would solicit no further enquiries on the matter, requesting privacy."
"Please don't confuse control systems with a domain controller. They're different things," he tweeted again.
A cyber security expert told that domain controller is like a local area network (LAN) whereas control systems are those that control the operation of the plant.
According to the expert, the control systems would get affected if anyone manually uses a pen drive used in the affected system in the computer systems connected to control systems.
However attempts by to get clarifications from NPCIL Chairman S.K. Sharma went in vain.
( With inputs from IANS )