A type of plutonium used in spacecraft could be headed to Savannah River Site for processing and, if no federal agency can use it, could be added to the millions of gallons of radioactive waste already on site.

The plutonium-238, packed in 55-gallon drums, would be trucked from one end of the country to the other under tight security, traveling from the Hanford complex in Washington to the Savannah River Site, near Aiken.

It would be a return journey for the plutonium, 40 years after SRS sent it to Hanford scientists, who later decided they couldn't use it. The decision on whether to send the plutonium back to SRS rests with Energy Secretary Samuel Bodman.

If the federal government can't find a use for the plutonium, it would add a small amount of waste to the SRS stream. But it would be yet more dangerous material for a site that works around the clock to process 37 million gallons of high-level radioactive waste.