> During normal operation, the primary is entirely contained within the primary containment, and circulates naturally, using the differential temperature and gravity. The steam system can is used to remove heat.

If it's using gravity, what happens if this whole reactor gets tilted? What happens at 10 degrees? 45? 90? 180? Are there any critical angles where it would melt down?

I'm curious how you would make such a design that would be both using gravity yet tolerate being moved around.