Except for the genets, caracals and other exotic wildlife ranging in the surrounding nature preserve, the pair of nuclear power reactors at Koeberg, South Africa, look much like their squat, domed counterparts dotting the United States. The basic technology is the same: beneath steel-reinforced concrete domes, the fission of uranium fuel generates turbine-driving steam.
Just like the United States, South Africa is also weighing difficult choices about how to meet future energy needs. The African nation doesn’t have much hydroelectric or natural-gas capacity. Coal is plentiful but dirty to mine and burn–and most of it is located too far from coastal population centers to make economic sense. And as in the U.S., many in South Africa believe nuclear power has a place in the future mix.
But there’s a key difference. So far, Washington is only talking about a nuclear rebirth; South Africa is getting ready to build. And Koeberg, on the Atlantic coast about 30 kilometers north of Cape Town, is emerging as the epicenter of a technology initiative that sponsors claim could usher in a new era of safe, inexpensive nuclear power using a long-studied and promising design: the pebble bed modular reactor. A construction decision by an industrial consortium is expected sometime this year. South Africa’s regulatory apparatus will get final say, but momentum behind the proposal is remarkably strong. “I believe that we will resolve all issues outstanding and this will get built,” says David Nicholls, CEO of the consortium, Pebble Bed Modular Reactor.
The consortium says the technology–rooted in research and prototype reactors that date to the 1960s–has matured to the point of achieving the twin goals that have eluded the nuclear industry in the post-Three Mile Island and Chernobyl era: affordability and inherent safety. First, a pebble bed reactor is relatively simple to build and inexpensive to operate; the consortium says construction and operating costs are expected to be “competitive” with those of coal and natural-gas plants. Second, and perhaps more crucial, they say, it is immune to today’s worst-case scenario: a loss of coolant in the reactor core that would lead to a melting of uranium fuel and a catastrophic release of radiation. That’s because the fuel is encased in billiard-ball-sized graphite “pebbles” that can’t get hot enough to melt. What’s more, this encasement may make the spent pebbles more rugged in long-term storage.
The fuel design isn’t the only thing that makes this reactor fundamentally different from the more than 430 commercial nuclear power reactors worldwide, nearly a quarter of which are in the United States.The pebble bed reactor is cooled with helium gas instead of water, operates at higher, more efficient temperatures and–thanks to the inherent safety claimed by its builders–dispenses with the containment dome and regional evacuation plan now required of U.S. nuclear facilities. Individual pebble-bed plants would also have a smaller footprint than today’s plants and produce a mere 100 megawatts or so of electrical power–a tenth as much as today’s typical nuclear behemoth. This modest scale limits the early financial losses many large plants incur by initially glutting the market with electricity, and gives utilities the option of building just what’s needed at first and then adding units later if demand warrants it.
Though pebble beds have advocates in utility boardrooms, their case is not yet proved in the eyes of the U.S. Nuclear Regulatory Commission. The agency hasn’t signed off on the safety of any of the plant’s features, from the fuel design to the lack of containment. And these reactors don’t solve the same two basic problems that dog the entire nuclear industry: they create highly radioactive fuel waste and are potentially vulnerable as terrorist targets. Nevertheless, the South African partners believe they can resolve regulatory questions and bring a pebble bed juggernaut to the United States. The consortium includes not only the South African government’s utility and industrial agency but also Chicago-based utility conglomerate Exelon and British Nuclear Fuels, owner of Pittsburgh-based reactor builder Westinghouse Electric. Already, Exelon is the largest U.S. nuclear-plant operator; its 17 reactors include the still-operating reactor at Three Mile Island near Harrisburg, PA, whose twin partly melted down in 1979, crippling the nuclear industry.
Exelon in particular sees pebble bed technology as the breeze blowing the nuclear industry out of its doldrums. Though it hasn’t yet made a construction proposal in the United States, the company envisions erecting clusters of pebble beds next to existing nuclear plants. “It is considered a very safe technology; it is relatively simple, it’s very efficient,” says Jim Muntz, vice president for nuclear projects. Asked whether Exelon wants to construct a pebble bed reactor in the United States, he answers unabashedly, “We want to build 40 or 50 of these. This isn’t about building one; this is about building a lot of them.”