That's not very similar to how WW2 started at all.
Anyway here's a link to the story:
http://news.bbc.co.uk/2/hi/middle_east/4301889.stm
Russia doesn’t seem to be joining forces with Iran, they're simply selling some of their plentiful Nuclear Fuel and by demanding that the used fuel is returned they are making it very clear that they do not want Iran to have Nuclear weapons. Even if Iran is secretly diverging fuel to a Nuclear weapons program it doesn’t mean they are going to use them. Thanks to mutually assured destruction a nuclear attack is very unlikely.