A Supreme Court ruling late last month in favor of the Monju prototype fast-breeder reactor may have been welcome news to its builder, the Japan Nuclear Cycle Development Institute, but putting the technology into practical use is still a long way away.

The top court upheld the government's 1983 approval to build Monju, once dubbed a "dream atomic reactor," paving the way to get it back online. The facility in Tsuruga, Fukui Prefecture, has been shut for more than nine years due to an accident and coverup.

Fast-breeder reactors like Monju are supposed to be able to produce more plutonium than they consume, and the government initially expected to get the technology into practical use in the 1970s.