Keep in mind that safety issues and cost are tightly coupled. To make nuclear cheaper, you need to make the parts more efficiently, and to build the reactors more efficiently, and to build more of them. All of these things increase the risks of an incident. Redesigned lower cost parts sometimes will be less reliable than the proven old design—see automotive for examples of this, 80 years after the invention of the automatic transmission, redesigned versions of it sometimes end up horrifically unreliable. A more efficient construction process involves less labor which means less eyes to spot a mistake. More reactors multiplies the small odds of a meltdown per reactor by more reactors.
Keep in mind that safety issues and cost are tightly coupled. To make nuclear cheaper, you need to make the parts more efficiently, and to build the reactors more efficiently, and to build more of them. All of these things increase the risks of an incident. Redesigned lower cost parts sometimes will be less reliable than the proven old design—see automotive for examples of this, 80 years after the invention of the automatic transmission, redesigned versions of it sometimes end up horrifically unreliable. A more efficient construction process involves less labor which means less eyes to spot a mistake. More reactors multiplies the small odds of a meltdown per reactor by more reactors.