Turkish Prime Minister Recep Tayyip Erdogan hailed the USD 22 billion contract as a "very important step" that would transform bilateral relations with Japan into a "strategic partnership".
A Japanese-French consortium won the giant contract to build Turkey's second nuclear plant, Japan's first successful bid on an overseas nuclear project since a tsunami wrecked the power station in Fukushima.
Turkey weathered criticism for teaming up with Japan in light of the catastrophe, but "despite that, we have taken this step," Erdogan said.
Japanese Prime Minister Shinzo Abe, who arrived in Turkey as part of a larger Middle Eastern tour, said that Japan had learnt important lessons from the 2011 catastrophe.
More From This Section
"Japan will share its experience and the lessons it has learnt and will contribute to the improvement of nuclear security at the highest level," Abe said in comments translated into Turkish.
Abe and Erdogan also signed an agreement covering the peaceful use of nuclear energy.
The French energy company Areva is to supply the plant's reactors in connection with Mitsubishi.
The Sinop plant is to comprise four reactors with a combined output of 4,800 megawatts. Construction is slated to begin in 2017, with the first reactor to be operational by 2023, an energy ministry official said.