This is very far from an obstacle, space-functional radiators and thermal management systems do exist.
Not saying I think it's the best idea, but it is theoretically feasible.
To say that this is pure folly is an understatement. It is not folly, and it is not foolishness. It is fraud.
One of the most cited papers: https://starcloudinc.github.io/wp.pdf
Does not contain the word "nuclear". Instead its just breathless gushing about how much more efficient the solar power is.
The radiators on the ISS radiate maybe 200kW all up. That's _one rack_ in a normal earthbound DC.