That is an unusual piece of common sense by the USN, with disasters such as the DDG 1000 and the LCS.
Thinking outside the box a little, how about a dual nuclear/oil fired drive? All four shafts are normally powered by the reactor, allowing the ship to have unlimited range at about 25 knots, and if they need to go faster, then they just fire up the boilers, and they can double the output of the power plant, and get up to 32, 33 knots. It also means reactors can be taken offline for maintance if anything goes wrong, and it won't turn the ship into a huge target. Minimizes risk and lowers costs? What isn't to like? I still couldn't see it built though.
Biggest problem I see is double the machinery in an era where the goal is to reduce personnel numbers, and loss of JP-5 bunkerage. Even if you use gas turbines that run on JP-5 the ship's machinery will still be reducing the volume of fuel available for air operations.
The next step, of course, is the exceptionally ambitious sea water to fuel effort that the Fleet is working toward. If it can be made to work, you could use the reactor to convert the JP-5 as needed to keep the bunkers full. That, however, leads to another set of machinery that requires personnel (the Fleet finally figured out that all those ordinary seamen weren't just free jackass labor the first Cruise/six months out of Q School)
Problem with the DDG-1000 was that it was a compromise of a compromise, that wound up compromising, cost a fortune ever time it bobbed or weaved. The LCS classes (both of them, not bad enough to be stuck with one white elephant) were even worse, no one ever did nail down the mission, mainly because there wasn't
A mission, they expected the same hull to do half a dozen different tasks with new, under development weapons and systems. They then proceeded to cancel several of the new systems (NLOS-LS, two separate mine hunting systems, etc.)that were supposed to allow the LCS to perform the missions outlined for it. Possible the worst moment was in 2011, when the Deputy Commandant of the Corps testified before Congress following a statement from a Congressman that the LCS program was costing the USN ten major amphibious units (which the Fleet really needs) and told the Committee that the LCS was being looked at to fill a number of the gaps in the 'Phib force. In 2015 the current Deputy Commandant told the same committee that the LCS was utterly unsuited due to issues with stability, berthing space and survivability in denied access zones. Why the big change?In 2011 the Chairman of the JCS was a four Star Admiral. In 2015 the Chairman was, for the first time, a Marine (the outgoing Commandant). Now there may have been some sudden change in the stability cabin space and survivabilty of the LCS classes in four years, or maybe, just maybe, the Chairman sent the Deputy Commandant in with a set of orders which he followed. (Wouldn't be the first time, back in the 80s the Commandant testified to Congress that the Corps wants more AV-8 Harriers not the F-14 to replace their F4 and A-6 airframes. Told them that in the morning. After the lunch break he informed the Committee that he was now requesting four squadrons of Tomcats as part of his budget. When asked why, he replied "Our mission has changed". NAVAIR literally called SECNAV and had "defending the fleet from cruise missile threats" added to the USMC's air operation responsibility during the lunch break. The fleet got 50 extra Tomcats and the Corps got something like 84 fewer Harriers.)
