In spite of the ban to ship nuclear fuel cycle products by rail across the territory of Ukraine, which was imposed by the State Nuclear Regulatory Inspectorate of Ukraine on January 28, 2014, the Fuel Company of ROSATOM TVEL will carry out all its fuel supply commitments before foreign NPPs. This can be achieved using an alternative licensed mode of transport, i.e. by air.
ROSATOM continues working routinely with all its foreign partners; they treat with understanding the route change issue. 
So the day before Ivan Genov, the Executive Director of Bulgaria’s Kozloduy NPP, stated in his interview with journalists: “Events in Ukraine will not affect in any way either supplies of fresh fuel to Kozloduy NPP or shipment of spent fuel. In such circumstances we have an option of shipping fuel assemblies from Russia by an airplane.” “This alternative has been already tested. However, at this time Units V and VI of the plant will not need refueling and can operate till the next spring using the available stock,” he said.
Source: Communication Department of ROSATOM