The Guardian reported that Sellafield, which carries out
nuclear fuel reprocessing, nuclear waste storage and decommissioning, had been
hacked by cyber groups closely linked to Russia and China.
"Our monitoring systems are robust and we have a high
degree of confidence that no such malware exists on our system," the
government said. "This was confirmed to the Guardian well in advance of
publication, along with rebuttals to a number of other inaccuracies in their
reporting."
Sellafield, controlled by the government's Nuclear
Decommissioning Authority, is located in northwest England and has 11,000
employees.
In a separate statement, Britain's Office for Nuclear
Regulation (ONR) also said it had seen no evidence that state actors had hacked
its systems as the paper had described.
But the regulator said Sellafield was currently not meeting
certain high standards of cyber security it required, adding that it had placed
the plant under "significantly enhanced attention.
"Some specific matters are subject to an ongoing
investigation process, so we are unable to comment further at this time,"
the ONR said.
The Guardian report said the ONR was "believed" to
be preparing to prosecute individuals at Sellafield for cyber failings.