Why are there no nuclear powered cruise ships?

[sparks1093]

1 hour ago, Charles4515 said:

That is a good point. A nuclear powered ship would probably not be allowed in many ports. Maybe most ports. And would the US allow foreign flagged nuclear powered cruise ships in our ports?

I was on a nuclear powered ship in the Navy and we always had to anchor out further away than most ships because of it. We never had less than a 30 minute boat ride to get into port and sometimes longer.

[Philob]

Fleet Week is happening right now in San Francisco. Navy's in town and the Blue Angels will start flying this afternoon if the fog lifts.

 

But many years ago I remember the first and only time a Nimitz carrier entered the bay for fleet week it never docked, just hung around Alcatraz, staying out of the way of regular shipping traffic. Those on shore leave got tendered and the VVIPs went by helo. Most of the planes flew off to San Diego before the ship went under the GGB. 

 

The Coast Guard and Navy was constantly busy trying to keep every lookie-loo/anti-nuke protestors with a boat away from the carrier.  

[K32682]

Considering the history of cruise lines dumping waste water and raw sewage at sea would anyone trust them to handle nuclear waste? 

[ldubs]

On 10/6/2022 at 10:08 AM, sparks1093 said:

I was on a nuclear powered ship in the Navy and we always had to anchor out further away than most ships because of it. We never had less than a 30 minute boat ride to get into port and sometimes longer.

 

The Nautilus -- first nuclear powered sub.  I had a model of it when I was a kid.   I know.  Not really a contribution to the thread, but it just brought back the memory.  

 

[bbwex]

It has been noted before, cost of a nuclear plant is really high.  Not to correct chengkp75, but the nuclear plant replaces the boilers, so you do not have to have boilers, and though the turbines to run the screws as well as the turbines to generate electricity are there, they might not be larger than the gas turbine system and generators that makes electricity on today's cruise ships.  I would presume that a nuclear-powered ship would run on steam, and no, a nuclear-powered ship does not need any other propulsion system for fast response.  Then too, much of the Navy's nuclear plant systems are classified, so you would have to find some company to make an initial design, get it approved, etc., etc., etc.  Without that, the initial cost is prohibitive, and the pool of people qualified to run a nuclear system is small.  The cruise industry does want to reduce emissions, but this is not a solution for them. 

 

I do not know whether nuclear-powered ships are prohibited anyplace, but security would be an issue.  I suspect that the NIMITZ anchored out in San Fran was because NAS Alameda is no longer operational and the NIMITZ is a very large ship.  They nuclear-powered ships go right up to the wharves in San Diego, but at a secure Navy base, and they do the same at Navy bases on the East Coast.  The Japanese government does not allow U.S. Navy ships to make port calls with nuclear weapons on board, but I never heard that that applied to the propulsion plants and the ENTERPRISE was serving at the same time we were in WestPac.  Someone from a nuclear-powered ship might be able to better answer that part of the question.

[dolittle]

The same reason Europe ( so worried about global warming) is doing away with nuclear (Zero emissions and going with coal ( the worst) . The same people who bow to science when they agree with it ,refuse to accept the science on nuclear and spread fear to people who are not very smart.

[chengkp75]

1 hour ago, bbwex said:

Not to correct chengkp75, but the nuclear plant replaces the boilers, so you do not have to have boilers, and though the turbines to run the screws as well as the turbines to generate electricity are there, they might not be larger than the gas turbine system and generators that makes electricity on today's cruise ships.

While you may not consider them "boilers", there is a heat exchanger that takes the secondary water system water, and boils it, using the heated primary water loop, and the steam then powers a turbine.  So, a gas turbine, for the same power output, would be much smaller than the steam turbine, the secondary water loop, the heat exchanger (boiler), and the reactor system.  This is established fact.  And, while the gas turbine holds a size advantage over diesel, diesel still holds a size advantage over steam.

 

1 hour ago, bbwex said:

I would presume that a nuclear-powered ship would run on steam, and no, a nuclear-powered ship does not need any other propulsion system for fast response.

I would suspect that a nuclear powered cruise ship would still use a turbo-electric propulsion system.  Steam turbines are notoriously slow in response to astern bells, and suck up enormous volumes of steam to get any power at all from them.  It also needs to be stopped to reverse.  Electric propulsion with SCR controlled speed is almost instantaneous in response, and a controllable pitch propeller can go almost directly from full ahead to full astern in seconds.  Steam turbines are slightly more efficient when going ahead, but dreadful when maneuvering.  There is a reason that the US merchant marine retained steam turbine propulsion after WW2 when the rest of the world converted to diesel, cheap fuel.  When fuel wasn't cheap anymore, after the Oil Embargo in the 70's, the US dumped steam like a hot potato, and converted to diesel.  Today, virtually the only steam ships operating are the LNG tankers, that use the boil off of cargo as fuel.

[d9704011]

10 hours ago, chengkp75 said:

would suspect that a nuclear powered cruise ship would still use a turbo-electric propulsion system. 

I don't believe there will ever be a nuclear powered cruise ship but the discussion is interesting.  In addition to steam turbo-electric power generation, the use of fuel cells (batteries) to store energy for other on-demand purposes other than main propulsion would likely be a feature.