...low quality heat? Nuclear reactors produce nothing but heat. And it's all just heat, how you transfer it is very independent of the production process
This is very wrong. Different processes require different temperatures. Iron and steel making requires very high temperatures. Heat from nuclear reactors cannot be used for this directly, as nuclear reactors do not get that hot, because they would melt. They are kept much cooler, usually at under 500 C.
Current reactor designs cannot get that hot without melting. I bet we could design a molten salt reactor that could safely get there, especially if electricity production is not a design goal.
I seriously doubt that. What would you make the reactor of, so that it withstands temperatures that melt steel? How are you going to move that coolant around? There are hard physical limits here. In reality, nobody would bother, because you can just make electricity and use it to melt steel instead.