BOISE — Federal officials will shut down an Idaho nuclear waste treatment project after determining it would not be economically feasible to bring in radioactive waste from other states.

The U.S. Department of Energy in documents made public this week says the Advanced Mixed Waste Treatment Project that employs 650 workers will end next year.

Officials say workers are wrapping up processing radioactive waste at the department's 890-square-mile (2,300-square-kilometer) site that includes the Idaho National Laboratory.

A $500 million treatment plant handles transuranic waste that includes work clothing, rags, machine parts and tools that have been contaminated with plutonium and other radioactive elements.

The department considered sending radioactive waste from Hanford in eastern Washington for processing but concluded it wasn't feasible.

The Post Register first reported the closure.