[SeeSharp]

Zakani said that Iran needs uranium enriched to 56% in order to fuel the propellants in submarines and for “other purposes.”

Pretty sure it only has to be 3.2% to fuel a nuclear reactor. Perhaps the small reactors in nuclear submarines require a bit more concentration for some reason, but not 56%.

More to the point, Iran doesn't have any nuclear submarines. They tried to get Russia to retro-fit one of their old Kilo class diesel electric subs with a nuclear reactor, but Russia declined. It was a lunatic idea. Iran has since announced that they are developing a reactor for submarine propulsion domestically, but Iran says a lot of things and this is not generally deemed a credible boast.

[Blood of Tyrants]

I’m thinking that they need 20% to be used for fuel and 95% for weapons. But I think that higher concentrations than 20% are needed for breeder reactors to produce plutonium 239 which is very useful for weapons and much easier to produce than weapons grade uranium.

[Conservat1]

"but Iran says a lot of things and this is not generally deemed a credible boast."

I hope, most take anything Iranians say with lots of grains of salt...