A Preassembled Nuclear Reactor

Babcock and Wilcox have a new small, modular reactor design. B&W are old hands, having built nuclear reactors for the United States Navy ships for about 50 years. En excerpt from MIT Technology Review:

…The new Babcock and Wilcox reactor design could make nuclear power plants less of a financial risk, Kadak says. The reactors are much smaller, designed to generate 150 megawatts each, but could also be strung together to generate as much as a conventional nuclear power plant. They also integrate two separate components of a conventional power plant in a single package: the reactor itself and the equipment used to generate steam from the heat that the reactor produces. As a result, the entire system is small enough to be shipped on a railcar. And because the system can be shipped, it can be manufactured at a central facility and then delivered to the site of a future power plant.

Building a reactor in a factory should save construction time, says Kadak. He estimates that what takes eight hours to do in the field could be done in just one hour in a factory. Once the reactor is manufactured, it would then be shipped to the site of a power plant along with the necessary containment walls, turbines for generating electricity, control systems, and so on. Christofer Mowry, CEO of Babcock and Wilcox, estimates that total construction time will be three years–at least two years less than conventional construction would take.

The reduced construction time could save on both construction and financing costs, since less time would be spent waiting for the plant to start producing power. The design also avoids a bottleneck in conventional nuclear power plant construction, which is that the large reactor vessel–a pressurized chamber containing the reactor core and necessary coolant–can only be manufactured in a few plants in the world, and none of these is in the United States, Mowry says.


Although the new reactors are smaller than conventional ones, they use the same underlying technology–they’re light water reactors–so Mowry says that it will be possible to get them certified under existing regulations. At least two other companies in the United States are developing small, modular light water reactors. One design, from Westinghouse, provided the template for combining the steam generator and the reactor, although it isn’t designed to be built in a factory. A startup called NuScale also has a design for a small modular system that can be built in factories and shipped to power plants. Those reactors would generate only about 40 megawatts each. Other companies and researchers, including Kadak, are developing designs for future modular reactors using more advanced technology that will require a new regulatory process.