[jddw]

You're right. It is also a common misconception that nuclear reactors cannot load follow, they can:

http://ansnuclearcafe.org/2013/02/14/responding-to-system-de...

One of the main limitations is the stress it puts on the fuel.

Many advanced reactors overcome these limits, and if financially incentivized, they will definitely load follow. On top of that, the UPower reactor has a thermal transport time constant nearly 10 times that of other reactors, and its fuel is immune to the shocks that bother LWRs. In fact, the same type of fuel was used in a research reactor and would be ramped in power from 5 watts to 150 billion watts in less than 50 millionths of a second. That puts a lot of stress on fuel, yet this fuel kept its stride without breaking a sweat.

This reactor is built like a tank, and is designed to be quite resilient and flexible. It can definitely load follow to support a renewable heavy grid system. In fact it's been considered for use as a grid stabilizer at substations because of these abilities.

[DennisP]

What kind of fuel and coolant does it use? Googling only turns up a couple fairly uninformative articles.