Hydrogen gas leaked at a nuclear power plant on inland's southern coast, east of Helsinki, yesterday, creating a risk of fire in the plant's yard but no danger to the nuclear process, officials said. A spokesman for the Loviisa plant, owned by power group Fortum, said gas leaked when the seal failed on hydrogen gas bottles used in maintaining the turbines, but the situation was under control. Firefighters from the town of Loviisa and the plant's ownfiremen were monitoring the leak.