Energy From Thorium Discussion Forum

Found this article on the economics of nuclear power for commercial shipping. I think LFTR could bring the cost down quite a bit, while reducing the weapons fear, and source term problems.

http://nextbigfuture.com/2009/07/nuclea ... pping.html?

A recent study conducted under the sponsorship of the Center for Commercial Deployment of Transportation Technologies (CCDOTT) examined the feasibility of a fleet of nuclear-powered 9,200-TEU containerships in a U.S. West Coast-Far East trade. The study, Analysis of High-Speed Trans-Pacific Nuclear Containership Service, conducted by George A. Sawyer and Joseph A. Stroud, General Management Partners, LLC, examined whether such nuclear-powered ships would be both technically feasible and economically competitive in such service. The study assumes that the timeline for the initial service would be 10 to 12 years in the future.

In the study, the conceptual design for the 9,200-TEU nuclear-powered containership was based on the lines of the diesel-powered OOCL Shenzhen. The nuclear-powered concept vessel ended up being lengthened by 42 meters to 365m (1,198 ft) overall in order to better accommodate the increased powering required. The lengthening resulted in a 4 knot improvement in the speed at the design horsepower and, because of the total weight saved by omitting about 8,900 tons net of fuel, permitted the load-out of an additional 1000+ 40 foot containers.

The study envisioned a hypothetical Rolls-Royce marine PWR nuclear-powered, 35-knot, three-ship express service making weekly calls between the Ports of Hong Kong and Long Beach/Los Angeles. This hypothetical service was compared with a four-ship 25-knot conventional service employing the same sized vessels using diesel technology.

The results of the comparison showed that under certain assumptions, the conceptual nuclear containership service would be economically viable with a crossover point compared to the diesel service at basic oil costs of about $89 per barrel.

Nuclear propulsion has for years proven economically essential in the Russian Arctic where operating conditions are beyond the capability of conventional icebreakers. The power levels required for breaking ice up to 3 meters thick, coupled with refelling difficulties that would be inherent with other types of power plant, are significant factors. The nuclear fleet has increased navigation in the region from 2 to up to 10 months per year.

Boy if anyone could find a copy of that study I would greatly appreciate it!

Yes - I am searching for it even now, I would have thought it would be more easily available.

Who would regulate its license? Ships are not always flagged in the country where the owners live.

What kind of engine would such a ship have if powered by a LFTR. Would you generate steam for a steam engine or a steam turbine? or ...Generate electricity for an electric motor.

What about a LFTR powered tug boat?

I think it would be an all-electric boat, using electricity from the primary generator(s) to drive podded electric thrusters.

Technically it's the country that the ship is flagged under, but in practice it would have to meet or exceed the requirements of the country at every port of call. This type of ship would not, for example, be able to dock at any port in New Zealand due to laws there forbidding nuclear-powered ships in it territorial waters.

Whereas such a vessel can not only legally dock in Australian ports, but even in Queensland ports (which are subject to the moronic Nuclear Facilities Prohibition Act 2007 (Qld) ), such a vessel would be legally allowed, as I read it, to hook up to the grid and feed power in.

Smells like an investment opportunity to me, fnord.

What, 40 kt+ transpacific catamaran clipper service? Or towing in a Sorenson-type submersible LFTR NPP and hooking the sucker up?

Just a reactor on a barge. If one can't build nuclear power plants on land in Oz, but you are allowed to float one in and hook up, I see a great loophole.

No, it would be much more efficient to just use most of the steam directly in a low pressure turbine for the main shaft, and part of it for electricity production. You will get ~30-35% conversion efficiency for electricity production, which then has to be used for motors, versus > 90% for direct drive using steam.

Refueling would be a concern, since you would not want to take the ship out of service every 18 months like a large commercial reactor. This is where a LFTR with a breeding ratio ~ 1 would be an logical fit. Run it for the lifetime of the ship, and then remove the salt and decomission the reactor vessel. Reuse the salt in the next one coming out of the shipyard.

Why is the direct drive efficiency > 90%. Isn't it the same 33% energy conversion as for shaft horsepower for the generator. I admit there may be losses of 5% or so in the generator and the motor.

I agree with Kirk, better to eliminate any steam plant and go with a brayton cycle turbine generator and electric thrusters. Or maybe use brayton cycle turbines directly to the propeller shafts, the LFTR should have no great difficulty load following variable shaft loads.

What we are going to see is the use of current marine nuclear power. There is a good reason why the study I mentioned called for a Rolls-Royce plant: they are proven, available technology. Mariners are a conservative lot and they won't be to quick to buy into something too radical.

Yes they use HEU because that is the best technology for this service.