From your link: "The most promising concept is a High-Temperature Gas-Cooled Nuclear Reactor heating helium to a temperature sufficient to steam reform hydrocarbons into reducing gases for the direct reduction of iron ores."
That still consumes fossil hydrocarbons.
Hydrogen can substitute for hydrocarbons in the production of direct reduced iron from iron ore.
"Assessment of hydrogen direct reduction for fossil-free steelmaking"
https://www.sciencedirect.com/science/article/pii/S095965261...
Hydrogen can of course be produced cleanly from nuclear power. But it's questionable if nuclear-derived hydrogen will be cheaper than other clean hydrogen sources.