The Finnish parliament began debating a controversial plan yesterday to bury waste from Finland’s nuclear power plants at a site some 1,600 feet underground. If the plan is approved, Finland will become the first country in the world to store nuclear waste deep underground. Environmentalists are protesting the proposal. Meanwhile, the Japanese government is poised to give final approval to the first nuclear power plant built in Japan since two workers were killed in 1999 in the country’s worst nuclear accident. A Lithuanian power plant said yesterday it had spilled a container of nuclear waste, though it said no changes in radiation levels occurred.