[Schroedingersat]

If you nuclear plant is only competitive 1 week a year (as the total cost of solar + wind can outcompete its O&M costs the other 51 weeks), then it needs to amortise the capital over about 30 weeks of operation once you take a small discount rate into account (even assuming an indefinite lifetime).

Then your $5000-$10,000/MWh energy is competing against any other 8 day storage option which costs less. Which is all of them.

On top of that, even using brown coal for that week is only adding 20g of CO2e/kWh to your energy on average. Better to do the 98% renewable grid first and then decide whether you're building the nuclear plant or storage

Delaying the transition by a couple of years while you build the plant is equivalent to running the 98% solution for half a century while you figure out something for the last 2% (which could still be a nuclear plant).