The power plant would be mostly buried underground for protection, and surrounded by a back-up passive air cooling system – hot air rises out of the exhaust stack and cool air is pulled in through low vents. This system would run continuously, essentially wasting about one percent of the heat generated, yet ensuring that the reactor would cool off in the case of a problem.
The reactor is partially self-regulating. If the temperature rises, the structures containing the fuel expand, causing the fuel to spread out, and slowing down the frequency of the neutron collisions that create the nuclear reaction. This, in turn, causes the temperature to fall. These features, says Wade, should simplify the control of the plant and prevent meltdowns.
The lead will also serve as a safety measure. The fuel will be delivered inside the lead in a solid form, to be melted on site. When this module is removed and replaced after thirty years, the lead will cool off – now encasing the used fuel. This can be returned to a central facility for reprocessing, after which almost all of the spent fuel can be reused, says Wade.
On the downside, building small reactors means losing out on the economy of scale that has driven a trend toward bigger and bigger reactors, says Wade. He hopes to make up for this by creating ways to mass-produce the reactors in modules that can be quickly assembled on site.
For Wade, small reactors are part of a vision for large-scale changes. “What we’re trying to do is not only change the technology, but also exploit it, by changing the infrastructures. You can ship thirty years of energy with a single core loading, to provide energy security for a country without the need to install the infrastructure [for processing the fuel] right on its own territory.” ElBaradei says designs such as the one developed at Argonne could actually “reduce access to sensitive nuclear material” if countries agreed to share fuel facilities. “We cannot afford to have every country sitting on an enrichment factory or reprocessing facility,” he says. If a country with such a facility begins to feel threatened, it “would be able to develop nuclear weapons within a matter of months.”
“We who live in the nuclear age are approaching a crossroads, a moment of truth,” ElBaradei told the audience at MIT. “Will this technology continue to be harnessed as a servant of development? Or will we become the victim of its destructive power?” For now, he says, “the benefits of nuclear energy are needed more than ever.”