Kansai Electric Power Co. said Thursday two freighters carrying a controversial nuclear fuel processed in France left the French port of Cherbourg for Japan the previous day and are expected to enter Japanese waters in the second half of June.

The experimental uranium-plutonium mixed-oxide fuel, or MOX, is to be loaded into the No. 3 reactor at Kansai Electric's Takahama plant in Fukui Prefecture on the Sea of Japan coast, it said.

The MOX shipment will be the first sent to Japan since the March 2011 meltdowns at the Fukushima No. 1 power plant.

The fuel has stirred controversy as it is made with old weapons-grade plutonium.

The two freighters are scheduled to follow a route off the Cape of Good Hope at the southernmost tip of South Africa, Kepco said.

Kepco has said it will aim to restart the reactor in July.