The headline in Pravda trumpeted President Vladimir V. Putin’s latest coup, its nationalistic fervor recalling an era when the newspaper served as the official mouthpiece of the Kremlin: “Russian Nuclear Energy Conquers the World.” The article, in January 2013, detailed how the Russian atomic energy agency, Rosatom, had taken over a Canadian company with uranium-mining stakes stretching from Central Asia to the American West. The deal made Rosatom one of the world’s largest uranium producers and brought Mr. Putin closer to his goal of controlling much of the global uranium supply chain. But the untold story behind that story is...