The core damage now unfolding in as many as four Japanese nuclear reactors after Friday's post-quake tsunami doused back-up cooling system generators is already becoming stock material for nuclear nihilists. Once again nuclear's perennial opponents are out in force hoping to use this episode to beat back nuclear power.
Greenpeace USA is asking its supporters to email the president and Congress with the suggested language "It's time to invest in clean, renewable energy. Not risky and dangerous nuclear power." This weekend Reuters reported on green parties in France, Italy, and Germany hurriedly parlaying Japan's reactors into a new ploy to push their respective governments away from nuclear. "We cannot master nature, nature rules us," Germany's Green Party parliamentary leader told the news agency
After a partial core meltdown at Three Mile Island
(TMI) in 1979, the American nuclear industry stalled out, overcome by NIMBY-ism. The country built one more nuclear reactor after TMI. While TMI injured no one, the accident wrought lasting devastation on the country's prospects for energy independence with its perfect storm of an ill-timed disaster movie and a sea of media misinformation. The University of Texas at Austin co-hosted a lecture and panel discussion last week on energy's portrayal in the movies. Michael Webber, a mechanical engineering professor at the university and an expert in energy and environmental policy, summed it up thusly, according to the event's Twitter feed
: "The China Syndrome
did for nuclear what JAWS
did for sharks."
Thanks to TMI, the United States has long lost much of the manufacturing infrastructure to efficiently build new full-scale gigawatt nuclear power plants. There are two plants under construction in Georgia, the first after this needless moratorium, and they are now so expensive that President Obama needed to approve a $8 billion loan guarantee (of an estimated $14 billion construction cost) so that Southern Company could obtain its financing for the huge project.
We shouldn't allow America's re-emerging nuclear industry to be swallowed up by a wave of misinformation following this devastating tsunami.
Nuclear is a key element of plans to minimize the impact of global warming. At 17 tons of carbon dioxide per gigawatt-hour, nuclear energy production actually emits less CO2 than wind (solar has nuclear beat by three tons per gigawatt hour). For reference, coal emits over 1,000 tons and natural gas over 600 tons for the same amount of energy. Facts like these have already swayed many environmentalists into the pro-nuke camp. Al Gore has carefully teetered on the edge of full-on nuclear support for some time now.
Holdouts refer to "safe energy" rather than "green energy" alternatives, aiming to exclude nuclear energy which towers over the green energy landscape as the most reliable source out there. Safe energy is a semantic trick along the lines of "pro-life," similarly implying a false dichotomy. That's because American-led nuclear design upgrades expected to power grids by 2020 change the terms of debate.
Meet the iNuke: small modular reactors chock full of elegant design innovations, built cheaply, operating efficiently, and buried underground for your protection. One of the most promising and practical designs is from Corvallis, Oregon-based NuScale
. They've got the safest reactor design the industry has ever seen, one that's drawing a scrum of serious shoppers as the company prepares to file for Nuclear Regulatory Commission approval next year.
"We think we're approaching a breaking point where plants are getting so complex and so large that it's reflected in cost," Dr. Jose Reyes, NuScale's chief technology officer, told the audience at MIT's Energy Conference
this month. Dr. Reyes drew intense interest from his rapt audience of MIT students and energy industry players at the conference's panel on small and medium nuclear reactors. He quickly got swarmed as his panel came to an end. I had to catch up with him later.
The Department of Energy funded Dr. Reyes and his Oregon State University team in 2000 as part of the Nuclear Energy Research Initiative. "We were commissioned to come up with a design that was small, compact and could be built easily," he told me, initially in the hope that it could be used in developing nations. The team built a functional model unit at their university lab as proof of concept, and NuScale used that lab while overhauling their plans into a commercially viable option. They ended up with a product that costs one-third of a traditional nuclear plant.
The NuScale mini reactor carries a risk of core damage of once in 100 million years. To put that expanse into some perspective, 100 million years ago, flowers had yet to evolve, and dinosaurs roamed the earth. It was the height of the Cretaceous period. Peer reviewed science will not back me up on my next assertion, but I think I have a fair shot of spontaneously turning into a porpoise about once in 100 million years.
We really shouldn't be awed by this kind of technological development, as unreal as it must seem to Green partiers everywhere. Japan's tsunami-drenched reactors are 40 years old. In the same time, space flight has evolved from impractical government-sponsored rockets and shuttles to the dawn of Virgin Galactic
. Nuclear just slimmed down too.
In this case, about 70 percent of NuScale's reactor design is similar to the most recent iterations of water-cooled enriched uranium reactors that are common worldwide and share a lineage to those in Japan. But a lot of mutation can occur with a 30 percent DNA swap out, and in NuScale's case, all of it points to safer operating conditions.
For one thing, rather than the huge gigawatt reactor of the kind capped by a massive concrete dome, a NuScale plant has up to 12 individual reactors made up of self-contained modules, each immersed in water and encapsulated by steel. The 65-foot long by 14-foot wide modules will be manufactured under controlled conditions at a central factory and shipped to sites, dramatically cutting down costs. Four modules can power the city of Madison, Wisconsin. All twelve can light up the entire metropolitan area of Memphis, Tennessee.
Because a NuScale plant is broken up into self-contained mini reactors of 45-megawatts each, the failure scenarios only pose so much risk, says Dr. Mohammad Modarres
, professor of mechanical and nuclear engineering at the University of Maryland and an international leader in the science of probabilistic risk assessment.
Probabilistic Risk Assessments (PRAs) are the most rigorous step for any engineering design, and take months to produce after numerous computer models based data sources like materials analyses. Engineers begin by brainstorming hundreds of possible system failures, searching for any possible way that radiation could find its way into the environment, and then determine a frequency for every conceivable scenario, in the end determining the possible consequences for each outcome. Three Mile Island had just such a PRA, which was highly prescient and laid out a scenario of system and human error virtually identical to what happened there, but the plant's owners and federal regulators didn't heed its warnings at the time. PRAs earned new status in TMI's aftermath.
The Nuclear Regulatory Commission requires PRAs for new designs and established plants alike, using methods standardized by the mechanical engineering profession. Much as the Food and Drug Administration mandates a series of clinical trials to assess the efficacy and safety of a prospective drug, the NRC's layers of regulators and outside consultants examine PRA data. Dr. Modarres performed NuScale's PRA just as he has done for large scale reactors and presented his findings at last year's International Probabilistic Safety Assessment & Management Conference
Dr. Modarres says NuScale is the safest reactor he's ever come across, 10,000 times less risk of any level of core damage than currently operating standard reactors, and it's 10 times safer than the Westinghouse AP1000 plants China's building now (pending NRC approval, it's also the design that will go up in Georgia).
So what if a natural disaster cut of external power to NuScale's water pumps that cool the reactor core -- the exact scenario now playing out in Japan?
It can't happen. There are no pumps.
In the NuScale plant, "You don't need a pump -- the heat creates a current of water by natural physics. Everything works by natural phenomena." Instead, the plant's steam generator tube is its weakest link, contributing the largest fraction of its 1 in 100-million-year risk. Physical properties of the tube which carries hot steam to the electricity-generating turbine come into play in the analysis. The tube could rupture, sending radioactive steam into the turbine and depriving the reactor core of water. In NuScale's PRA, Dr. Modarres created technical models of possible wear and tear of the pipe and its safety valves that could occur over the years. "We calculate through the 'physics of failure' an estimated frequency for this event," he says. The model gets even more complex, as the reactor automatically replenishes its water (or human operators can do so) through chemical volume control systems. The PRA models have to take into account the likelihood of this system failing too.
NuScale takes advantage of its design simplicity during its pre-NRC submission phase to change out elements and see how that affects its PRA (that pipe may get further tweaking before the NRC sees it). Such revisions on the fly aren't even possible with most larger more complex plants.
The reactor's size is one of its most important safety features. At 1/26th the size of standard reactors, there's simply less radioactivity to let loose. Dr. Reyes told the MIT crowd, "We've not only reduced the frequency of possible accidents, we reduced the consequences of accidents. That's huge psychologically." People who are afraid of flying don't really care about the frequency of accidents he says, it's the huge consequences of a single accident. "We've eliminated that."
Dr. Modarres explains the worst-case disaster scenario this way: "Even if one of the reactors fails and releases its radiation into the containment vessel, and again if that containment vessel fails and releases its material, it would be releasing that material into water, which is one of the best scrubbers for radioactive material." Ultimately a small amount of radioactive gases could make their way into the atmosphere, but mind you the whole operation is in an underground silo.
Since each module has its own separate metal containment vessel (unlike the traditional design of concrete domes that are getting repeatedly blasted in the hydrogen-fueled explosions at the Fukushima Daiichi plant), the probability of two reactors both leaking radiation is the probability of two independent extremely unlikely events. Even more reactors? Infinitesimal.
What about a major earthquake? "Being inside water, the forces that would be applied to the modules is much less. It's floating inside the water, so they wouldn't have as much force as if they were tied into the ground." Detailed seismic assessments are still being built into the model, and depend on location, but Dr. Modarres does not expect such events will increase major risk significantly.
Representative Edward Markey (D-MA) was sounding the alarm bells this weekend, yesterday sending a letter to President Obama requesting a moratorium on new nuclear power plants, reminiscent of European Greens. In light of the dire challenge posed by global warming, the growing destabilization in OPEC countries, and the ingenuity of America's nuclear engineers, the more appropriate federal response to the vulnerabilities in old nuclear plant designs that we share with Japan is to fully back nuclear energy 2.0 companies like NuScale.