A large percentage of the cost of a nuclear power plant is the construction and installation of the plant itself. This cost can vary and increase if the site has challenging weather and other conditions. Also, cold and harsh environments may not have a highly trained local workforce to build each plant.
Building floating nuclear reactors means that the factory or shipyard can be at the most productive and efficient location.
A shipyard is more streamlined and efficient than construction sites because there is more automation, a better-trained workforce, a more controlled environment and no exposure to the elements.
A floating nuclear power plant (FNPP) offers useful flexibility. They can be moved if the demand moves. An oil or gas project may only need power for 10 years, so the nuclear plant can move from one oil and gas project to the next.
The ocean can be used as a heat sink to cool the reactor for added safety.
Russia is planning to produce seven floating nuclear reactors. Russia completed one and it will be used for an Arctic oil and gas projects.
China is looking to make twenty floating reactors and possibly more. China should be completing the first of its floating reactors in 2019.
Indonesia might launch mass production of Thorcon molten salt floating reactors
ThorCon is developing molten salt floating nuclear reactors. They use the same steam and electrical side as a standard 500 MWe supercritical coal plant. But gone are the massive coal handling systems, the 100 m high boiler, the flue gas treatment system, and the ash handling and storage system. A generous estimate of the overnight cost of the ThorCon steam side, everything but the nuclear island, is $700/kW. This is a well-established number.
The total overnight cost of a 500 MWe coal plant is between 2000 and 1400 dollars per kW. Both figures assume no attempt at carbon capture. ThorCon would be 2 to three times cheaper than coal.
The ThorCon nuclear island requires one-sixth as much steel and one-fourth as much concrete as the portion of the coal plant upstream from the turbine. A 1 GWe ThorCon nuclear island requires less than 400 tons of superalloys and other exotic materials. ThorCon operating at near ambient pressure has a 2:1 advantage in steel and a 5:1 advantage in concrete over its nuclear competitors on the nuclear side. Much more importantly, very little of ThorCon’s concrete is reinforced. Reinforced concrete is impossible to automate, drives the critical path, is not amenable to block construction, and entombs the critical portion of the plant in a mausoleum making repair and replacement extremely difficult. ThorCon can be produced entirely in bargable blocks at shipyard assembly line productivity.
Based on resource and labor requirements and allowing for stringent inspection and testing, the ThorCon nuclear island should cost less than $500 per kW on an overnight basis.
Thorcon wants to provide Indonesia initially with 7 cents per kwh power that can be moved to any of the hundreds of islands in Indonesia. The costs should then go down with later units.
ThorCon uses exactly the same proven modular ship building production process except the blocks are barged to the site and dropped into place.
The Hellespont Metropolis is one of eight ships built by ThorCon’s predecessor company. This ship is the largest double hull tanker ever built. She can carry 440,000 tons of oil. Her steel weight is 67,000 tons. She required 700,000 man-hours of direct labor, a little more than 10 man-hours per ton of ship steel. About 40% of this was expended on hull steel; the rest on outfitting. She was built in less than 12 months and cost 89 million dollars in 2002.
A 1 GWe ThorCon is so small that the nuclear island easily fits into three center tanks of the Hellespont Metropolis, and requires one-fourth as much steel as a very large tanker.
This steel requirement is roughly equivalent to a medium size, 125,000 dwt Suezmax tanker. Compared to a 1GWe ThorCon, the Suezmax requires more steel (23,000 tons vs 15,000) and is larger overall (270 m by 50 m by 23 m versus 150 x 30 x34). The ship’s structure is far more complex and subject to tougher loads. The Suezmax has far more coated surface. The Suezmax can move herself at 15 knots, survive a hurricane, and discharge her cargo in about a day. A good shipyard can profitably build a Suezmax for 60 million dollars.
A big shipyard can turn out 100 of these ships a year. It could easily manufacture 100 one GWe ThorCons per year.
In terms of resource requirements, a 1GWe ThorCon is not a big deal.
A 1 GWe ThorCon requires an initial fuel charge of 3,156 kg of 20% Low Enriched Uranium. We also need to add 11 kilograms of this fuel per day. Every 8 years the fuel must be changed out. The uranium is easily recoverable, but we do not give ourselves any credit for this. Assuming a yellowcake cost of $66 per kg, a conversion to UF6 cost of $7.50, and 90 dollars per SWU, ThorCon’s levelized fuel cost is 0.53 cents per kilowatt-hour. See the Executive Summary for details.
Every 8 years the plant will end up sending about 160 tons of spent fuel back to the recycling facility. This material will be about 75% thorium, with 95% of the remainder valuable uranium. Even if we don’t attempt any separation, other than boiling off the salt, the total fuel waste stream averages about 2 m3 per year.
ThorCon has more than a 4:1 advantage over coal in fuel costs, and at least a 50,000:1 advantage in solid waste volume. If the easily separated uranium is re-enriched, then ThorCon’s fuel cost will drop further, and uranium requirements will be nearly halved.