[John Rogers]

The subs today use natural circulation so the electric coolant pumps do not have to run. By this I mean when the reactor core gets the pressurized (2000 PSI or so) water hot it goes up to the steam generator where it makes 500 PSI water into steam and due to heat loss the reactor coolant then goes down to get reheated. The General Electric and early Westinghouse reactors used on the USS Enterprise and all the Cruisers were backwards, with hot water going down? Soooooo in the case of loss of power and no coolant pumps you had to get power back quickly to prevent core over heating!

Twice in the 20 years I spent as a nuclear machinist we lost all power twice on ships I was on and had trouble getting those big diesels started and would watch the core temperature meter like a hawk! At the D1G prototype training site in New York we did a test when core 3 was installed to see if natural circulation was possible.....it was not.
John