[en] The Experimental Breeder Reactor - II (EBR-II) at Argonne National Laboratory West in Idaho, was shutdown in September, 1994 as mandated by the United States Department of Energy. This sodium cooled reactor had been in service since 1964, and was to be placed in an industrially and radiologically safe condition for ultimate decommissioning. The deactivation of a liquid metal reactor presents unique concerns. The first major task associated with the project was the removal of all fueled assemblies. In addition, sodium must be drained from systems and processed for ultimate disposal. Residual quantities of sodium remaining in systems must be deactivated or inerted to preclude future hazards associated with pyrophoricity and generation of potentially explosive hydrogen gas. The sodium environment and the EBR-II configuration, combined with the radiation and contamination associated with thirty years of reactor operation, pose problems specific to liquid metal reactor deactivation. The methods being developed and implemented at EBR-II can be applied to other similar situations in the United States and abroad