MOSCOW, Dec 30 (Reuters) - Russia kept up its flow of positive Y2K vibes on Thursday, saying everything from the Mir space station to the country's lifeline railway network would be immune to the millennium computer bug.

Western nations say Russia, home to nine Soviet-era atomic power plants and thousands of nuclear missiles, is one of those most at risk when January 1, 2000 arrives. A glitch means some computers may read 2000 as 1900 and crash or malfunction.

On Wednesday, Deputy Prime Minister Ilya Klebanov, who heads Russia's Y2K task force, said he was certain things would go smoothly and the Strategic Rocket Forces reiterated all their missiles would stay put when midnight strikes.

Other Russian officials gave similarly upbeat reports on Thursday as crunch time neared in the world's largest country.

Midnight strikes first in Russia's Far East on the international dateline opposite Alaska and then sweeps across the country's 11 time zones.

"The arrival of the New Year will not affect computers at Mission Control,'' Mikhail Pronin, chief engineer at Russia's space headquarters near Moscow, told Itar-Tass news agency. "We don't expect anything to happen because of the 2000 problem.''

Sergei Gorbunov, spokesman for the Russian Space Agency, told Tass the Mir orbital station had been equipped with new computers that outperformed even those at Mission Control.

The 13-year-old station has been crewless since two Russians and a Frenchman returned to earth in August. A lack of funds means Russia is unlikely to be able to extend Mir's life.

Russia is helping to establish an International Space Station, the first modules of which are already in orbit. Gorbunov said this station was also Y2K-proof, not least because it was kitted out with modern Western computer systems.

Back on earth, Russian railway officials said they were confident their network, second only to the U.S. rail system in length, would work smoothly. But staff have been trained how to work without computers if there is a problem.

Air officials said they were fully prepared, and so did FAPSI, the government's secret communications agency.

The United States and Britain, among others, place Russia near the top of their Y2K worry list. Several countries have withdrawn non-essential diplomatic staff from Moscow.

Russian officials say they may have started late and with little money but they do not envisage major problems.

Many Russians are unfazed by the Y2K problem and are much more concerned with preparations to celebrate the New Year, traditionally the most important holiday in Russia's calendar.

Two-thirds of the 667 people who telephoned Ekho Moskvy radio for a poll said they did not think Y2K would affect them.

Russia's navy said its nuclear submarines and conventional fleet were safe.

"The multi-layered control system completely rules out the possibility of a computer fault causing the unsanctioned use of nuclear weapons by combat vessels,'' Vice-Admiral Mikhail Barskov, the navy's Y2K chief, told RIA news agency.

The Strategic Rocket Forces say they have completed checks on automatic systems governing land-based nuclear rockets.

As an extra safeguard, Russian specialists are in the United States at a command center in Colorado, and began work on Tuesday with U.S. experts to watch for any false warnings of missile attacks sparked by the millennium computer bug.

They will keep a joint watch over Russia's 2,000 nuclear-tipped missiles and 2,440 U.S. rockets for three weeks.

Russia's electricity firm RAO UES said people should not try to save energy on New Year's night because that could give officials the wrong impression about generating needs.

"UES earnestly asked citizens not to overload their minds with global problems and to direct their energies to greeting the New Year happily,'' Tass said.