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Navy aircraft carriers
US Navy aircraft carriers continue to be the centerpiece of the forces necessary for operating forward. In times of crisis, the first question leaders ask is: “Where are the carriers?”
On any given day, Sailors aboard an aircraft carrier and its air wing come to the fight trained and equipped across a full range of missions. They are ready to control the sea, conduct strikes, and maneuver across the electromagnetic spectrum and cyberspace. No other naval force fields a commensurate range and depth of combat capabilities.
Today the US Navy operates 11 carriers, all nuclear-powered: ten 101,000-ton, 1,092 ft long Nimitz class carriers and Gerald R. Ford (the lead of the class Gerald R. Ford) 110,000-ton, 1,106 ft long carrier.
All these carriers are powered by two nuclear reactors.
What powers an aircraft carrier if nuclear reactors have to be shut down
But if both nuclear reactors on a Nimitz or Ford class aircraft carrier had to be shut down, how would the ship stay combat effective, or self-sufficient? What would provide power to the ship?
Michael Fiedler, former Electrician’s Mate Nuclear on USS John C Stennis (CVN-74), explains on Quora;
‘Former EMN1(SW) here (Electrician Mate Nuclear Surface Warfare). I was stationed aboard the USS John C Stennis for 4.5 years and actually participated in this scenario as a casualty drill and then actually coordinated and “ran” it a couple times on watch teams as a Propulsion Plate Drill Team Coordinator. I was also qualified Load Dispatcher, who is pretty much in charge of the electrical distribution of the aircraft carrier and would be in charge during restarting the reactors and steam plants.
‘For starters, we have four emergency diesel generators with enough fuel (jet fuel) to help with the restoration. Out of the X amount of load centers on the ship, there are Y amount that we label as “red breakers”, which if this scenario you propose happens (we call it a DIW — Dead in the Water) are the only breakers we won’t trip out because they are vital ships loads (combat systems, medical, comms, etc.) or they are load we need in order to restart. Big picture, we take a lot of actions to minimize power and steam demand. Steam demand is important because the more steam we use the more the reactors cool down which makes it harder, or take longer, to restart them.
Not defenseless
‘Once we figured out what caused both of the reactors to scram and we meet all initial conditions, we are able to restart because the big thing we want to do is get propulsion back. It isn’t a good idea to be that big of a target and not moving anywhere. After that, everything else as we are able to. Hopefully, depending on the watch team and initial conditions, you’ll have everything back up anywhere from an hour to three.’
Fiedler concludes;
‘Are we really “dead in the water” if this happens? Not so much. We still have power to all of our combat systems and defensive measures on the ship, which is a good amount; we can still launch helicopters, but not planes since we are trying to conserve steam unless they were already out. We also usually travel in a combat group which includes frigates, cruisers, and subs. Will the ships’ combat abilities be greatly effective? Definitely. Are we defenseless? Not really. And as mentioned before, the emergency gens will be able to provide enough power before we get started back up.’
Photo credit: U.S. Navy
