"If nothing extraordinary happens, next year we will not deliver anything for storage in Russia," the acting head of Energoatom, Petro Kotin, said in a statement.

The ex-Soviet country of some 40 million people has four operational nuclear power plants which provide about half of its electricity.

Of the four, only the Zaporizhzhia plant -- the largest in Europe -- has its own storage depot for spent nuclear fuel.

Ukraine, which has been fighting separatists backed by the Kremlin in its east since 2014 following Moscow's annexation of the Crimean peninsula, pays Russia $200 million per year for storing the spent fuel, an Energoatom spokesman told AFP.

According to Energoatom's statement, the operator completed the first part of the new depot for storing spent nuclear fuel in the Chernobyl exclusion zone earlier this month.

Energoatom said that US energy equipment and systems supplier Holtec International supported the construction.

It added that it plans for the depot, which is meant to last for a century, to intake the first spent fuel in May next year.

In 1986, an explosion at the Chernobyl nuclear power plant left swathes of Ukraine and neighbouring Belarus badly contaminated and led to the creation of the exclusion zone roughly the size of Luxembourg.

The Chernobyl station continued operating even after the world's worst nuclear disaster, finally closing in 2000.

Ukraine recently announced plans to get the area included on the UN culture agency UNESCO's heritage list alongside landmarks like India's Taj Mahal or Stonehenge in England.