That seems unlikely. If, for example, you run at a loss 50% for the time, then you need to have extra expensive rates during the other 50% of the time. Based on typical construction costs of nuclear power plants, those high rates are extremely attractive for competition from wind and solar. Which will reduce the amount of power that can be sold at premium rates, which requires even higher rates to compensate, etc.
Basically, in a free market, nuclear power is competing with power from batteries, hydrogen, and other ways of storing electricity.
This is an extremely unattractive market for nuclear.
> Do you dump the energy at a loss
Yes, if you dump energy at loss is still not a total loss, and you still make money if you above water longer than you aren't.
The point of making the reactor that powerful is exactly to get more profit even at super low rates.