Production
Shipyard productivity, shipyard quality
To supply the electricity that the emerging economies so desperately need, we will require 100 one GWe Thorcon 500 power plants per year for the foreseeable future. And we need them soon. We need a system for producing fission power plants, not individual fortresses. Fortunately such a system exists. It’s called a shipyard.
Thorcon’s genesis is in ship production. The Hellespont Fairfax 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 good shipyard needs about 5 man-hours to cut, weld, coat, and erect a ton of hull steel. The yards achieve this remarkable productivity by block construction. Sub-assemblies are produced on a panel line, and combined into fully coated blocks with piping, wiring, HVAC (and scaffolding if required) pre-installed. In the last step, the blocks, weighing as much as 600 tons, are dropped into place in an immense building dock.
Block construction is not just about productivity. It’s about quality. Very tight dimensional control is automatically enforced. Extensive inspection and testing at the sub-assembly and block level is an essential part of the yard system. Inspection at the block level can be thorough and efficient. Defects are caught early and can be corrected far more easily than after erection. In most cases, they will have no impact on the overall project schedule.
Thorcon brings shipyard quality and productivity to fission power. But Thorcon 500 structure is simpler and much more repetitive than a ship’s. The nuclear module employs steel plate, sandwich walls filled with 3 to 6 meters of water. This results in a strong, air-tight, ductile building, all simple flat plate. A properly implemented panel line will be able to produce these blocks using less than 2 man-hours per ton of steel.
Visit a shipyard building a Thorcon 500 nuclear power plant.
First fly around a cutaway 3D model of a complete Thorcon 500 power plant. Visit a busy ocean-side shipyard. Pilot your small craft to the construction shipway. Watch blocks of a nuclear module being assembled. A semi-submersible heavy-lift ship carries the nuclear module to the destination site, then partially submerges, floating off the nuclear module. Tugboats position it adjacent to the steam module with the supercritical steam turbine-generator. Ballast water is added to settle it to the prepared seabed. 500 MW of electric power flows to the grid.
A Thorcon 500 power plant may instead be towed to its site.
Small is beautiful
Fissile fuel has a million times more energy than fossil fuel. Not only does this mean that fuel requirements (and waste) for a big power plant are measured in kilograms per day rather than thousands of tons per day; but it also means that, if you operate at low pressure, the plants can be small. The Thorcon 500 reactor operates at near ambient pressure. It does not need much space. Nor does it consume a lot of resources. In fact, the Thorcon nuclear module is so small that almost fits into two center tanks of the Hellespont Fairfax, and requires one-fourth as much steel.
The steel weight of a 500 MW ThorCon is about 50,000 tons. The world’s largest shipyard can build more than 2,000,000 steel tons of ships per year. At that rate a single shipyard might produce 20 GW’s of ThorCon 500 power per year. In terms of resource requirements, one gigawatt of ThorCon power is not a big deal. The scale up rate will not be limited by shipyard capacity, but by the rate at which the supercritical steam turbogenerators can be built. We’re planning ten 500 MW power plants per year, per shipyard.
If it breaks, send it back
In the ThorCon system, no complex repairs are attempted on site. The nuclear module itself can be swapped out with little interruption in power output. Rather than attempt to build components that last 40 or more years in an extremely harsh environment with nil maintenance, ThorCon is designed to have key parts regularly replaced.
Up to 50 ThorCon plants are supported by a maintenance center and a separate fuel facility. Normally, the nuclear module is swapped out every eight years. At the maintenance center, the Cans and drain tanks are disassembled, cleaned, inspected, and worn parts replaced. The problems of decontamination and waste disposal are shifted from the plant to this facility.
This system of regular replacement of the most critical components means that upgrades can be accomplished without significantly disrupting power generation. And since the returned Cans are disassembled and fully inspected after every four years of use, incipient problems will be caught before they can turn into accidents.
Such renewable plants can operate indefinitely; but if a ThorCon is decommissioned the process is little more than pulling out but not replacing all the replaceable parts.