A 5 MW reactor takes about 5 kg of fuel per year. For an experiment, we purchased decaborane for $5 per gram or $5,000/kg. At that price fuel costs would be $25,000/yr or 0.05 cents/kWh. Electricity now costs about 5 cents/kWh.
Actually, these prices are based on the fact that decaborane is sold in very small quantities. It would be much cheaper with mass production. In the 1950