The Nuclear Installations Inspectorate (NII) is taking the threat of the "9/9/99" bug sufficiently seriously to have asked all nuclear operators to prepare contingency plans.
A Health and Safety Executive spokesman said that in order to prove that they can shut reactors down safely in an emergency, nuclear operators have to take the date into consideration as part of their safety assessments, without which they are not allowed to operate. "We don't think the 9/9/99 bug is widespread but nevertheless it is being taken seriously around the world as a potential date for trouble," the spokesman said.
The fresh concerns about millennium-type problems came on the day that the Global Positioning System - a network of 24 navigation satellites controlled by computer chips - resets its date to zero.
The "roll over" of the GPS occurs every 1,024 weeks - about once every 20 years - and was due to take place at midnight last night, potentially causing problems for anyone with a hand-held receiver, such as hikers, sailors and light-aircraft pilots. Although the NII did not issue any warnings about the GPS rollover, it has taken the potential risks of computer failure due to the 9/9/99 bug more seriously.
Tony Stock, the Operations Director of Action 2000, the government task force set up to deal with millennium bug issues, said the 9 September bug stems from a historic accident when computer files were processed according to date, with the earlier dates being dealt with first. To ensure that any totalling of the records was done last, programmers inserted the "nonsense" date of 99/99/99, which was guaranteed to be later than anything else in the computer files.
"This, we believe, has been misconstrued as 9/9/99, a real date rather than the dummy value. Our assessment and the US government's assessment is that we don't anticipate any major problems," Mr Stock said.
Just two authenticated examples of the 9/9/99 bug have so far emerged: one in test equipment used by the rail industry to monitor vibration in tracks, and one in a piece of medical equipment, which did not endanger patients. Some computer users see the bug as a test for the millennium bug proper at the end of the year.
Businessmen were yesterday warned they could face legal action if they fail to take precautions against the millennium bug. Don Cruickshank, chairman of the government's Action 2000 bug watchdog, told firms they could be liable if it prevents them from fulfilling a contract or if their faulty systems disrupt another company. Millennium bug damage is unlikely to be covered by insurance as it is a foreseeable event.