Preparations for shipping MOX, or mixed oxide, fuel to be used in a recently restarted nuclear reactor in Fukui Prefecture, central Japan, is underway in northwestern France.
Two vessels designed for shipping nuclear materials are expected to leave the port of Cherbourg on Wednesday.
French nuclear energy firm Areva manufactured the recycled fuel, which is a mixture of plutonium extracted from spent nuclear fuel and uranium.
The MOX fuel is to be used in the No.4 reactor at the Takahama nuclear plant, which Kansai Electric Power Company restarted in May.
Two specially designed casks containing MOX fuel assemblies were mounted on the vessels by a crane after they were transported to the port on a trailer.
Security was tight as anti-nuclear activists rallied near the port.
According to Areva, this is the sixth time the company is shipping MOX fuel to Japan and the second time since the 2011 nuclear accident in Fukushima Daiichi nuclear plant.
The company says the shipment will take about two to three months, but that the route will be announced in two weeks as a precaution.
Areva is facing worsening business conditions as more countries aim to phase out nuclear power plants. The company's spokesman said it hopes to continuously provide MOX fuel to Japan.