Optimistically, if you finance the original US$7.17 per peak watt at 3% per year, that capital is costing you 21.5¢ per year per peak watt. If you can run the reactor at an optimistic 95% capacity factor, that's 22.6¢ per average watt. There are 8765 hours in a year, so that's 2.6¢ per kilowatt hour or US$26 per megawatt hour. That's just the cost of building the plant; operating costs are added on top of that.
https://pv-magazine-usa.com/2020/05/28/record-low-solar-ppas... describes a recent photovoltaic PPA in Texas (not in Utah, but not far away) that's selling solar energy for US$15 per megawatt hour, and a battery-storage PPA that's selling at US$30/MWh, and notes that prices that year at the Palo Verde energy trading hub (in Arizona, a bit nearer to Utah) averaged US$26.58/MWh. With new generation capacity coming online and selling at $15 in the daytime and $30 at night, it's going to be hard to sell nuclear energy in the Southwest at $26/MWh plus opex and transmission costs. (The LCOE estimate in the POWER article, based on the original US$4.3 billion estimate for 600 MW capacity, was US$65/MWh). You can't turn your nuclear plant off in the daytime just because PV is driving LMPs negative. (And turning it off wouldn't reduce your capex even if you could, just your opex—maybe.)
Part of the problem is the quote from the former chair of the Nuclear Regulatory Commission in https://www.sciencemag.org/news/2019/02/smaller-safer-cheape...: "Nuclear does not do anything quickly." And that makes it expensive.
As I said three weeks ago, nuclear energy is the Amiga of energy sources: https://news.ycombinator.com/item?id=26674832
If this is what "Smaller, safer, cheaper" looks like, it's a definition of "cheaper" I'm not familiar with. How did this project get off the ground in the first place? Under what analysis did it look like a good deal?