BELGRADE, July 18 (RIA Novosti) - Bulgaria has returned to Russia a spent nuclear fuel consignment from a research reactor, the Bosnian news agency SRNA said on Friday, citing Bulgaria's nuclear control agency.
It said the fuel transportation costs were covered by the U.S. Department of Energy.
The fuel for Bulgaria's Academy of Sciences' nuclear reactor was first supplied by the Soviet Union in 1961 - the year it was put into operation - and was used until it was closed down in 1989.