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.