[1] This nuclear reactor utilizes natural circulation[2][3][4] which is capable of operating at a significant fraction of full power without reactor coolant pumps.
A land-based prototype of the reactor plant was built at Knolls Atomic Power Laboratory's Kesselring Site in West Milton, New York.
In 1994, the core was replaced with an S6W reactor, designed for the then-new Seawolf-class submarine.
The prototype is equipped with an automatic reactor fill system that can flood the reactor with borated water in the event of a loss-of-coolant accident.
The S8G reactor is in use in Ohio Class Submarines and has a power rating of 26.1 MW.