The Japanese government decided to decommission the nuclear " Monju," the fast breeder reactor after a series of safety concerns. 
The government officials declared it's decommission plan for the fast breeder reactor during a meeting with the Japanese officials of Fukui district. 
They also revealed a plan to develop a new fast breeder reactor, taking in consideration the previous lessons learned from developing " Monju." The government is also reviewing the formation of trial reactor at the location of where the reactor Monju was developed and it is attempting to dedicate the area for further nuclear development and investigation. 
Japanese officials announced previously that the decommission of the fast breeder reactor Monju will entail high financial costs. Officials estimations show that the restoration of the nuclear fuel might take up to five and a half years, while the decommissioning of the fast breeder reactor Monju might take up to thirty years. 
It's estimated that Monju was turned on for only 250 days since it's operation in 1994.

Source: QNA