A nuclear power plant in Germany has been found to be infected with computer viruses, but they appear not to have posed a threat to the facility's operations because it is isolated from the Internet, the station's operator said on Tuesday.
The Gundremmingen plant, located about 120 km (75 miles) northwest of Munich, is run by the German utility RWE.
The viruses, which include "W32.Ramnit" and "Conficker," were discovered at Gundremmingen's B unit in a computer system retrofitted in 2008 with data visualisation software associated with equipment for moving nuclear fuel rods, RWE said.
Malware was also found on 18 removable data drives, mainly USB sticks, in office computers maintained separately from the plant's operating systems. RWE said it had increased cybersecurity measures as a result.
W32.Ramnit is designed to steal files from infected computers and targets Microsoft Windows software, according to the security firm Symantec.
First discovered in 2010, it is distributed through data sticks, among other methods, and is intended to give an attacker remote control over a system when it is connected to the Internet.
Conficker has infected millions of Windows computers worldwide since it first came to light in 2008. It is able to spread through networks and by copying itself onto removable data drives, Symantec said.
RWE has informed Germany's Federal Office for Information Security (BSI), which is working with IT specialists at the group to look into the incident.
The BSI was not immediately available for comment.
After Japan's Fukushima nuclear disaster five years ago, concern in Germany over the safety of nuclear power triggered a decision by the government to speed up the shutdown of nuclear plants. Tuesday was the 30th anniversary of the Chernobyl nuclear disaster.