The new Lightbridge fuel design

Aerial view of the NuScale Plant.

Say “nuclear reactor” and what leaps to mind is a giant machine, powerful enough to run an entire city, with thousands of moving parts.But UPower Technologies has a different concept: a nuclear power plant that is mostly built in a factory, and arrives on site in two standard shipping containers. After set-up, it runs a cluster of buildings or a village. The reactor is more like a nuclear battery, with no moving parts.UPower is one of several new reactor concepts that will be the topic of discussion in the next few days. Third Way , a centrist think tank, holds an Advanced Nuclear Summit and Showcase on Wednesday. Third Way recently issued a report on the future of nuclear power, in partnership with three Department of Energy laboratories: Idaho, Argonne and Oak Ridge. In November, the White House held a summit on nuclear energy Behind the events is the conviction that with technological progress, nuclear power, like microchips or composite materials or a lot of other evolving technologies, can turn up in new applications, in new places.Take UPower. Today, almost all reactors sit on the power grid, where they contribute to a system with many different sources, but off the grid, the big source of energy is diesel generators.These have a variety of drawbacks. Often the fuel has to be hauled long distances, so getting diesel fuel requires burning diesel fuel. Sometimes the fuel comes over routes that are open only seasonally. A reactor like UPower’s could run for ten years without refueling. Like a diesel generator, UPower’s reactor has an output is in the range of megawatts. (For reference, a gasoline-powered generator you buy at a hardware store is usually in the kilowatt range, and a house with a central air conditioner will draw several kilowatts; a megawatt is about as much power as it takes to run a Super Walmart. A typical reactor today is in the range of 1,000 megawatts.)Diesel is by far the most expensive fuel, and can be the most polluting. And often, people who rely on a diesel generator are paying five or ten times as much, per kilowatt-hour, as customers on a major grid. So the economics of a tiny reactor might not work on a major grid, but would be very attractive in places that are off grid. According to the International Energy Agency ’s World Energy Outlook , 1.2 billion people have no access to electricity and another 2.7 billion rely on “traditional biomass,” everything from wood to dung, burned indoors in poorly-ventilated spaces.Upower is not alone in this idea; Toshiba’s 4S design (Super Safe, Small and Simple) has already attracted interest in Alaska and elsewhere. But Toshiba, Upower and others face obstacles in coming to market, one of which is the high cost of licensing a new reactor design. City officials of Galena, Alaska, wanted a Toshiba reactor as an alternative to shipping in diesel fuel in the brief window when barges can get to the town, but the Nuclear Regulatory Commission told them that the town and the company would have to pay the NRC’s costs for licensing the plant. But around the world, such reactors have tremendous environmental promise, for cleaning up indoor air, reducing deforestation caused by burning wood, and reducing air pollution from dirty diesels.By Third Way’s accounting, 48 companies, with more than $1.6 billion in private capital, are pursuing advanced reactor technologies.Some are fission, some are fusion. One, Lightbridge, is not pursuing a new reactor, but rather, a new fuel form that can go into existing reactors. Existing fuel uses uranium in ceramic pellets, stacked in long metal tubes called fuel rods. Lightbridge uses uranium embedded in metal, shaped like a liquorish stick. The design as 35 percent more surface area, so it gives off its heat more easily. The Lightbridge fuel is intended to run at less than 700 degrees F, and give off about 10 percent more heat than a conventional fuel rod, which heats to over 2,000 degrees. That creates the opportunity to get more electricity out of current reactors, with fuel that is even less likely to overheat.All these technologies face years of development work, but Lightbridge recently won permission to try out its fuel in a test reactor in Norway Also marching ahead is NuScale , which has a design for clusters of small reactors, installed in a sealed capsule in a large pool of water. The cores are so small, relative to their surface area and the cooling ability of the pools, that fuel damage becomes impossible. NuScale went the opposite route from Lightbridge; its design uses a type of fuel that has been used for decades, except half the size. The strategy reduces the number of new technologies that must be approved.And there is also government help. On January 15, the Energy Department announced that it would provide funds to x-energy and a group that includes TerraPower and Southern Company to develop new reactor designs. X-energy is working on a high-temperature “pebble bed” design, and the TerraPower/Southern group is planning a molten chloride fast reactor. Pebble beds produce a higher-temperature steam with many uses, and fast reactors make better use of fuel, and their used fuel contains fewer long-lived materials.There is more to come. Watch this space.