I had no idea. But on looking it was the US, then Russia. “Iran's nuclear program was launched in the 1950s with the help of the United States under the Atoms

I had no idea. But on looking it was the US, then Russia. “Iran's nuclear program was launched in the 1950s with the help of the United States under the Atoms for Peace program” https://en.m.wikipedia.org/wiki/Nuclear_program_of_Iran https://en.m.wikipedia.org/wiki/Nuclear_program_of_Iran