CORVALLIS — Jose Reyes has a surefire way to make certain that in case of accident, his nuclear reactor is surrounded by plenty of cold water: install it at the bottom of a giant swimming pool.
After the triple meltdown of the Fukushima nuclear plant in Japan in March 2011, a swarm of new ideas about nuclear power drew attention. One of those is the brainchild of Reyes, who came up with a scheme to make a reactor small enough so that if there is a loss of electric power, as happened at Fukushima, its tiny core will cool on its own, and quickly, the way a small cup of coffee chills faster than a big pot.
His reactor, which so far exists only in computer designs, sits inside a containment vessel that looks like a steel thermos bottle and measures 82 feet in height and 15 feet in diameter — a mini version of reactor containments, some of which are being constructed at 200 feet in height and 120 feet in diameter at United States nuclear plants.
Although Reyes' reactor delivers only one-twentieth the power of conventional reactors, his design is such that more reactors can be added as more power is needed.
His reactors would rest inside 10-million-gallon tanks of water, mostly below ground, which Reyes says will lower the chance of meltdown to a thousandth of the risk of conventional reactors.
Should all go wrong in one of his reactors and it boils over, he said, the resulting steam would hit the cold outer wall that borders the pool and condense back into water to cool the core.
“The goal was simplicity,” said Reyes, a co-founder and chief technology officer of NuScale Power, located on the edge of the campus of Oregon State University, where the company operates a simulator to try out some of its key concepts.
By industry standards, his concepts are far from the beaten path. Afraid of big pipe leaks? The NuScale reactor has no pipes bigger than 3 inches. Worried about pump failures? Eliminate the pumps and rely on thermodynamics, because the NuScale reactor is small enough to rely on the natural, cooling circulation that occurs because hot water rises and cold water sinks. Afraid the emergency diesel generators won't work? This design doesn't require them.
Outsiders see virtues but also pitfalls.
“You can pull it off if you have a small enough thermal mass,” said Revis James, director of energy technology assessment at the Electric Power Research Institute, a utility consortium. James was referring to the hot core of the reactor. A small reactor could achieve a defense against meltdown that would be impossible in a larger one, he said.
The downside is that getting a new design licensed by the Nuclear Regulatory Commission, an essential precursor for sales in the U.S., could cost as much as $1 billion. No one in the industry is really sure, however, because no one has done it in a number of years.
Additionally, the level of opposition, and the difficulty in getting approvals and permits, might not be much different for a small reactor than for a big one, some experts say, diminishing the logic of going small.
For the economics to work, builders would have to convince regulators that the smaller plants can get by safely with less robust containment structures, smaller evacuation planning zones and smaller security forces. And the industry has always calculated that with economies of scale, bigger means cheaper.
At the Union of Concerned Scientists, a nonprofit group that generally takes a dim view of all things nuclear, Edwin Lyman, a physicist, argued in a recent paper that the Energy Department should not support any designs with smaller emergency planning zones or less robust safety features.
Other companies recognize the advantages of small reactors, so NuScale is not alone.
Babcock & Wilcox, a former builder of big reactors, is pushing a 180-megawatt design (four times the size of NuScale's reactor) and has won support from the Department of Energy. The department is expected to issue a similar grant to another designer soon; a grant that NuScale is chasing.
Among the benefits, smaller reactors are considered potential export products.
Some of the safety projections for the NuScale reactor are tested in a two-story-high simulator that measures, for example, how fast heat will travel through a piece of metal the thickness of the one planned for the thermos bottle. There is also a control room, with 12 identical computer displays, simulating a dozen reactors in the giant pool.
Kevin Deyette, a former senior reactor operator at the Columbia Generating Station, a conventional reactor near Richland, Wash., and now at NuScale, used the simulator to demonstrate how the design would handle a malfunction like the one that led to the Three Mile Island accident in 1979.
Normally, steam made by the reactor is used to spin a turbine and make electricity. The steam is then condensed into water and pumped back to the reactor to carry away more heat.
In the simulation, the pump failed and the reactor boiled over into the thermos bottle, like a pot left too long on the stove. But when the steam hit the thermos bottle — which is kept cool by the surrounding water of the pool — the steam was condensed back into water, eventually filling the thermos bottle, flowing back into the reactor and ensuring further cooling.
It was not an accident, Deyette said, but an “upset condition,” with no damage and no danger.
NuScale is talking to a variety of potential customers, although mostly not in the U.S., where the low cost of natural gas has made it hard for nuclear power to compete.
Not so in Europe or in Asia, where natural gas prices are far higher. “It's not hard for us to compete elsewhere,” said Michael McGough, the company's chief commercial officer.
Regardless of its export potential, the reactor will not be ready for market for about a decade.
The company has, however, persuaded one important partner: Fluor, an engineering company that specializes in power plants and built many of the reactors now in service in the U.S. Fluor has invested $145 million in NuScale, on top of about $20 million the company has raised elsewhere.
One big step forward would be the end to the government shutdown, which is delaying the awarding of a federal grant for small nuclear reactor development.