Even if the Paris Agreement is implemented, food and water supplies remain at risk

If all pledges made in last December’s Paris climate agreement (COP21) to curb greenhouse gases are carried out to the end of the century, then risks still remain for staple crops in major “breadbasket” regions and water supplies upon which most of the world’s population depend. That’s the conclusion of researchers at the MIT Joint Program on the Science and Policy of Global Change in the program’s signature publication, the "2016 Food, Water, Energy and Climate Outlook," now expanded to address global agricultural and water resource challenges.

Recognizing that national commitments made in Paris to reduce greenhouse gas emissions fall far short of COP21’s overarching climate target — to limit the rise, since preindustrial times, in the Earth’s mean surface temperature to 2 degrees Celsius by 2100 — the report advances a set of emissions scenarios that are consistent with achieving that goal.

According to the authors, meeting the 2 C target will require “drastic changes in the global energy mix.” To explore what those changes might entail, MIT Joint Program researchers and contributors from the MIT Energy Initiative and the Energy Innovation Reform Project identify current roadblocks to commercializing key energy technologies and systems, and the breakthroughs needed to make them technically and economically viable.

To project the global environmental impacts of COP21 and model emissions scenarios consistent with the 2 C target, the 2016 Outlook researchers used the MIT Joint Program’s Integrated Global Systems Modeling (IGSM) framework, a linked set of computer models designed to simulate the global environmental changes that arise due to human causes, and the latest United Nations estimates of the world’s population.

Implications for agriculture and water resources under COP21

Assuming a global emissions path based on COP21, Joint Program researchers used statistical models they developed that replicate complex, numerically demanding globally gridded crop models to project the future productivity of the Earth’s “breadbasket” regions. The projections show overall increased yields through 2100 of maize in the U.S. and wheat in Europe, but taking advantage of these increases would likely require a significant shift northward of farming operations from where these crops are currently produced. The results also show an overall increase for upland rice in Southeast Asia and soybean in Brazil, with a more mixed pattern of yield increases and decreases appearing within these broad regions.

The authors attribute much of agriculture’s gains from climate change to increases in carbon dioxide concentrations, which can act like a fertilizer and also improve crops’ water-use efficiency. However, they note research indicating that such yield increases may be accompanied by reductions in nutrient and protein content. They also caution that while climate change may give some areas an advantage, extreme heat and drought linked to a changing climate are likely to increase the frequency of major crop failures. In addition, significant disparities in yield changes across breadbasket regions could lead to costly relocations of farming operations. Finally, the crop models upon which this report’s statistical models are based constitute an important, but recent, development, and will require more work to better represent current yields if there is to be confidence in future projections.

The 2016 Outlook also projects that under COP21, the water stress index (WSI), a common measure relating water use to water availability, will increase in most regions as a result of increasing demand due to population and economic growth (particularly in developing countries), as well as from changes in climate. The largest relative increase in the WSI is found in Africa, mainly driven by increases in population and economic growth.

The authors conclude that approximately 1.5 billion additional people will experience stressed water conditions worldwide by 2050, of which approximately 1 billion will experience heavily to extremely stressed water conditions. Uncertainty in the climate-change pattern plays a role in both where people will face water stress and what level of water stress they will face.

“Our results indicate that even the COP21 climate-mitigation actions are insufficient to curtail all risks of increasing global water scarcity by midcentury,” says Adam Schlosser, deputy director of the MIT Joint Program. “To make salient risk reductions in unmet water demands by 2050, many nations will need to consider broad adaptive measures that increase the efficiency of water consumption as well as viable options to increase water-storage potential. Our continued analyses will be bringing the most cost-effective options to bear.”

Implications for energy and climate under COP21

As detailed in the 2015 Outlook and reviewed in the 2016 report, assuming that COP21 pledges are met and retained in the post-2030 period, the global mean surface temperature is projected to rise 3.1–5.2 C above preindustrial levels by 2100, far higher than the 2 C threshold identified by the United Nations Framework Convention on Climate Change as necessary to avoid the most serious impacts of climate change, from rising sea levels to more severe precipitation patterns to increased wildfires. The global mean precipitation increase ranges from 3.9 to 5.3 percent by 2050 relative to the preindustrial level, and 7.1 to 11.4 percent by 2100.

By the MIT Joint Program’s estimate, the planet’s emissions path under COP21 will result in atmospheric greenhouse gas (GHG) levels that far exceed those consistent with the Paris Agreement’s 2 C goal. Even with low climate sensitivity to GHG emissions, on this path, the 2 C target will be passed shortly after 2050. The 2016 Outlook therefore lays out three global emissions path scenarios — based on the global climate exhibiting low, medium, or high sensitivity to atmospheric GHG levels, respectively — consistent with keeping the global temperature rise below 2 C, and assesses prospects for low-cost, low-carbon energy technologies that could support those scenarios. 

“The Paris Agreement made energy projections particularly important, as it calls for a goal that requires an energy system based on a radically different fuel mix that what’s been developed to date,” says Sergey Paltsev, deputy director of the Joint Program. “In our report we show that the timing of this shift and the exact contribution of a particular technology will depend on many economic and political variables. Such uncertainty about future costs and technologies supports a conclusion that governments should not try to pick the ‘winners,’ rather the policy and investment focus should be on targeting emissions reductions from any energy source.”

Prospects for low-cost, low-carbon energy technologies

Depending on how technology, policy, the economy and public opinion evolve, a variety of different energy technologies such as nuclear, renewables, biomass, or carbon capture and storage could play a dominant role in enabling an emissions pathway consistent with the 2 C goal. In detailed analyses of energy technologies where innovation could facilitate a lower-carbon future, the 2016 Outlook examines technical and economic barriers and hoped-for breakthroughs in nuclear energy, biomass energy, solar electricity, electricity storage, the electricity grid, and carbon capture and storage.

Alongside these analyses, Joint Program researchers, by assuming different mixes of costs and technology-cost ranges estimated by the International Energy Agency, portray scenarios in which one or another of these advanced technologies plays a dominant role. These scenarios are illustrative, and not necessarily tied to specific advances described in the contributed perspectives.

“While it’s hard to predict exactly which of these technology advances will prove out, I’m confident that with substantial R&D investment, we’ll see significant advances — and cost reductions — in one or more of them.” says John Reilly, co-director of the Joint Program. “As a result, the cost of stabilizing greenhouse gases will come down to a level where countries will find it much easier to move forward on climate policy.”

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Tata Center Symposium seeks collaboration for a better world

In 2004, the Boston Red Sox staged an epic comeback to the beat the New York Yankees four games to three in a playoff series. It was one of the most iconic moments in the team’s history, but it wasn’t hitting, pitching, or fielding that made the difference.

The real reason for the improbable victory was revealed Sept. 16 at the second annual MIT Tata Center Symposium.

“We were doing some magic back home in India,” joked Shrashtant Patara, a longtime Red Sox fan who is vice president of the non-governmental organization Development Alternatives, based in New Delhi, India.

Patara was one of more than 30 distinguished guests, most of whom had traveled from India, who gathered at the MIT Media Lab with around 250 attendees, including MIT faculty, graduate students, and members of the greater Boston community. The had come to talk about collaboration, and not just as it pertained to winning baseball games.

As the Tata Center kicked off its fifth year, a critical question was on the table: How can MIT researchers more effectively join forces with companies, NGOs, and governments in the developing world to tackle persistent challenges to human development and environmental sustainability?

A keynote address by David Ferguson, director of USAID’s Center for Global Innovation, emphasized building connections with the communities most acutely affected by problems like drinking water scarcity, lack of sanitation, and financial exclusion: “We believe that those closest to the problem are the most likely to find a solution.”

At the same time, he noted that 700 million people still live in extreme poverty, and “we can’t be satisfied with solutions that reach only a small number of people.”

To get the conversation started, almost 50 MIT faculty members, representing a wide array of disciplines, gave short “lightning” presentations on their developing world research supported by the Tata Center.

In the energy session, Professor Rajeev Ram of the Department of Electrical Engineering and Computer Science highlighted his team’s uLink technology, and their efforts to work with local entrepreneurs to install microgrids in Indian villages. Niven Winchester of the MIT Energy Initiative described how he and Assistant Professor Valerie Karplus of the MIT Sloan School of Management are modeling low-carbon development pathways for India, trying to help the country meet its pledges from the 2015 UN climate meetings in Paris (COP21).

In health and housing, Professor Lee Gehrke shared his work to create rapid diagnostic tests for mosquito-borne viruses like Zika, Dengue, and Chikungunya, while Assistant Professor Miho Mazereeuw explained the Urban Risk Lab’s suite of projects to increase disaster resilience, such as real-time flood mapping in south India and creating smart public infrastructure in Nepal.

And in water and agriculture, Aga Khan Professor of Architecture James Wescoat detailed his growing partnership with the government of India to build new frameworks for managing rural water supply. Professor Martin Bazant of the Department of Chemical Engineering discussed his system of water purification through shock electrodialysis, and Assistant Professor Amos Winter of the Department of Mechanical Engineering described breakthroughs in drip irrigation technology that could make farms more productive and sustainable.

The afternoon belonged to the visitors, who represented dozens of India’s most influential foundations, grassroots organizations, and companies. Most are already active collaborators on Tata Center projects, and they gave their reactions, suggestions, and insights.

Partho Sengupta, head of echocardiology at Mt. Sinai Hospital in New York, identified a relationship between the way India’s cities are growing and health risks such as pulmonary and cardiovascular disease. “Urbanization has direct consequences on health,” he said, calling for cross-disciplinary teams of epidemiologists and urban planners to look at such problems holistically. Sengupta is collaborating with Rich Fletcher, a research scientist affiliated with the Tata Center and D-Lab, on smartphone-based health tools.

Malavika Chauhan, executive director of the Himmotthan Society, which promotes development in the Himalayan region, urged researchers to think of relationship-building as a fundamental part of solving technological problems, echoing Ferguson’s keynote speech. “Networking and partnerships with communities are the foundation of our organization.”

Patara said his organization “is interested in collaborating with MIT on anything to do with water filtration and microgrids.”

The Tata Center’s efforts to build connections in the developing world are linked to MIT’s larger campaign to engage with global challenges around human health and the health of the planet, and to translate innovative research into entrepreneurial impact. That work continues year-round, and the third annual Tata Center Symposium will be held at MIT in Fall 2017.

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Innovador sistema de inspección de las redes de alumbrado público

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Changing the face of conservatism in the U.S.

In 1966, when the conservative writer William F. Buckley launched a television talk show, it may not have seemed like a promising endeavor, on the surface.

The show, “Firing Line,” was initially not broadcast on a television network but syndicated to local stations. Even in a lower-tech era, “Firing Line” was low-tech: It simply showed Buckley against a bland backdrop, glass of water nearby, talking for an hour with guests.

Yet “Firing Line” did not just survive on the air for more than three decades; it thrived. Through Buckley, the show became a central platform for the effort of some conservatives to move the Republican Party to the right and, at the same time, bring intellectual respectability and credibility to the conservative movement.

“With ‘Firing Line,’ Buckley forged an appealing mainstream image of right-wing conservatism,” says Heather Hendershot, a professor of film and media in MIT’s Comparative Media Studies/Writing program. Buckley, she adds, showed “that conservatives could be urbane and sophisticated and intelligent, and they weren’t just raving lunatics.”

Hendershot has written a new book about the show, “Open to Debate: How William F. Buckley Put Liberal America on the Firing Line,” released this week by HarperCollins publishers. In it she analyzes the program’s history, dissects Buckley’s views, and makes the case for the program as a “compelling model” of political engagement with opponents, of a kind missing from politics today.

Empowered after defeat

“Firing Line” emerged in the wake of the 1964 presidential election, when Republican nominee Barry Goldwater moved the party to the right, away from its Eisenhower-like moderates, but lost by a landslide to the Democratic president, Lyndon Johnson.

“Goldwater failed miserably in terms of votes but empowered the right-wing Republicans to come forward,” Hendershot says. Buckley’s goal was to establish conservatives as intellectuals — not merely hawks, social reactionaries, or conspiracy theorists — in American life, while maintaining a free-market, strongly anticommunist ideology.

The Republicans regained control of the White House in 1968, thanks to Richard Nixon, but like some others on the right, Buckley frequently found that Nixon was not conservative enough for his taste.

“Almost everything about Nixon was problematic from Buckley’s point of view,” Hendershot observes. “Like so many hard-right conservatives of the time, he was offended that Nixon spent so much on housing and urban development and put money into American domestic programs. They certainly objected to him going to China.”

By contrast, the election of Ronald Reagan in 1980 helped push American politics further right. For Buckley, and other movement conservatives, it was a triumphal time — although it may not have been the peak of “Firing Line” as a program, perhaps because all that political success took an edge off the show’s oppositional frisson.

The numerous visits of Reagan to the program, Hendershot suggests, were “not typically gripping shows,” apart from one extended episode when Buckley and Reagan disagreed about the Panama Canal treaties, a contentious issue of the time.

By contrast, Hendershot — having watched an enormous amount of the show’s archives while researching the book — thinks some of the most gripping “Firing Line” episodes come when Buckley debated feminist leaders. Buckley was, to be sure, a traditionalist about gender roles, Hendershot believes, without being too reflexively opposed to successful women.

“Buckley felt women shouldn’t feel pressure to work if they didn’t want to … but he celebrated smart, powerful, and — especially — conservative women who were in the workplace,” Hendershot says. “He thought strong, talented women would just rise to the top.”

Yet as Hendershot recounts, the noted feminist Germaine Greer, author of “The Female Eunuch,” did so well on the “Firing Line” that Buckley even sent her an admiring letter after one appearance.

Civil rights — and civil debates?

Buckley had a seemingly more fraught role in the civil rights debates of the time. In 1957, as Hendershot notes, he had written a controversial piece in The National Review, “Why the South Must Prevail,” that was distinctly skeptical about the civil rights movement.

Yet toward the end of his life, Hendershot recounts, Buckley acknowledged he had been mistaken about the issue, in the sense that “the [federal] government really needed to intervene” to create stronger rights for blacks.

Yet Hendershot concludes that Buckley’s views on race were “much more complicated than [people] would initially think,” something that comes out on “Firing Line” shows where he is interrogating segregationists such as Strom Thurmond and George Wallace.

“They actually were on very different pages,” Hendershot says, adding: “There are all kinds of surprises when you watch the show.” For instance, she adds, “Buckley had sympathy for [the] Black Power [movement] in certain ways, because of its emphasis on personal empowerment, community organizations, and localism” — ideas he saw as consistent with conservative principles, even as some civil rights activists argued that greater integration would not be achieved through such means.

“Firing Line” went off the air in 1999, after 1,429 episodes, and Buckley died in 2008, just as the political landscape was shifting once again. The election of President Barack Obama that year, Hendershot observes, has helped foment a “resurgence of right-wing extremism and conspiratorial thinking” of the kind Buckley once tried to detach from conservatism.

“We are in a moment when the loudest voices seem to be the most extreme,” Hendershot says.

And as strongly as Buckley held to his conservative views, Hendershot thinks, he promoted on “Firing Line” a very different ethos of public debate than the one we have today.

“You could come to it as a conservative and become a better, smarter conservative, or come to it as a liberal and become a better, smarter liberal,” Hendershot says. “He was willing to accept that people might listen to a liberal and think, ‘That’s a good idea.’ But he thought he would win. That is a kind of model that we can take a lot from.”

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Water vapor sets some oxides aflutter

When one type of an oxide structure called perovskite is exposed to both water vapor and streams of electrons, it exhibits behavior that researchers had never anticipated: The material gives off oxygen and begins oscillating, almost resembling a living, breathing organism.

The phenomenon was “totally unexpected” and may turn out to have some practical applications, says Yang Shao-Horn, the W.M. Keck Professor of Energy at MIT. She is the senior author of a paper describing the research that is being published today in the journal Nature Materials. The paper’s lead author is Binghong Han PhD ’16, now a postdoc at Argonne National Laboratory.

Perovskite oxides are promising candidates for a variety of applications, including solar cells, electrodes in rechargeable batteries, water-splitting devices to generate hydrogen and oxygen, fuel cells, and sensors. In many of these uses, the materials would be exposed to water vapor, so a better understanding of their behavior in such an environment is considered important for facilitating the development of many of their potential applications.

A video taken from a transmission electron microscope shows a perovskite material oscillating as it is exposed to water vapor and a beam of electrons. Video has been sped up. (Courtesy of the researchers)

Like cooking polenta

When a particular kind of perovskite known as BSCF — after the chemical symbols for its constituents barium, strontium, cobalt, and iron — is placed in a vacuum in a transmission electron microscope (TEM) to observe its behavior, Shao-Horn says, “nothing happens, it’s very stable.” But then, “when you pump in low pressure water vapor, you begin to see the oxide oscillate.” The cause of that oscillation, clearly visible in the TEM images, is that “bubbles form and shrink in the oxide. It’s like cooking a polenta, where bubbles form and then shrink.”

The behavior was so unexpected in part because the oxide is solid and was not expected to have the flexibility to form growing and shrinking bubbles. “This is incredible,” Shao-Horn says. “We think of oxides as brittle,” but in this case the bubbles expand and contract without any fracturing of the material. And in the process of bubble formation, “we are actually generating oxygen gas,” she says.

What’s more, the exact frequency of the oscillations that are generated by the forming and bursting bubbles can be precisely tuned, which could be a useful feature for some potential applications. “The magnitude and frequency of the oscillations depend on the pressure” of the vapor in the system, Shao-Horn says. And since the phenomenon also depends on the presence of electron beams, the reaction can be switched on and off at will by controlling those beams.

The effect is not just a surface reaction, she says. The water molecules, which become ionized (electrically charged) by the electron beam, actually penetrate deep into the perovskite. “These ions go inside the bulk material, so we see oscillations coming from very deep,” she says.

This experiment used the unique capabilities of an “environmental” transmission electron microscope at Brookhaven National Laboratory, part of a U.S. Department of Energy-supported facility there. With this instrument, the researchers directly observed the interaction between the perovskite material, water vapor, and streams of electrons, all at the atomic scale.

Keeping its shape

Despite all the pulsating motion and the penetration of ions in and out of the solid crystalline material, when the reaction stops, the material “still has its original perovskite structure,” Han says.

Because this is such a new and intriguing finding, Shao-Horn says, “we still don’t understand in full detail” exactly how the reactions take place, so the research is continuing in order to clarify the mechanisms. “It’s an unexpected result that opens a lot of questions to address scientifically.”

While the initial experiments used electron beams, Shao-Horn questions if such behavior could also be induced by shining a bright light, which could be a useful approach for water splitting and purification — for example, using sunlight to generate hydrogen fuel from water or remove toxins from water.

While most catalysts promote reactions only at their surfaces, the fact that this reaction penetrates into the bulk of the material suggests that it could offer a new mechanism for catalyst designs, she says.

In addition to mechanical engineering, Shao-Horn holds joint appointments with the Department of Materials Science and Engineering and the MIT Energy Initiative’s Center for Energy Storage. The research team also included Kelsey Stoerzinger PhD ’16; Vasili Tileli of the Ecole Polytechnique Federale de Lausanne, in Switzerland; and Andrew Gamalski and Eric Stach of Brookhaven National Laboratory, in Upton, New York. The work was supported by the National Science Foundation, the Skoltech-MIT Center for Electrochemical Energy Storage, and the U.S. Department of Energy Office of Science. 

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3-D-printed robots with shock-absorbing skins

Anyone who’s watched drone videos or an episode of “BattleBots” knows that robots can break — and often it’s because they don’t have the proper padding to protect themselves.

But this week researchers at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) will present a new method for 3-D printing soft materials that make robots safer and more precise in their movements — and that could be used to improve the durability of drones, phones, shoes, helmets, and more.

The team’s “programmable viscoelastic material” (PVM) technique allows users to program every single part of a 3D-printed object to the exact levels of stiffness and elasticity they want, depending on the task they need for it.

For example, after 3-D printing a cube robot that moves by bouncing, the researchers outfitted it with shock-absorbing “skins” that use only 1/250 the amount of energy it transfers to the ground.

“That reduction makes all the difference for preventing a rotor from breaking off of a drone or a sensor from cracking when it hits the floor,” says CSAIL Director Daniela Rus, who oversaw the project and co-wrote a related paper. “These materials allow us to 3-D print robots with visco-elastic properties that can be inputted by the user at print-time as part of the fabrication process.”
   
The skins also allow the robot to land nearly four times more precisely, suggesting that similar shock absorbers could be used to help extend the lifespan of delivery drones like the ones being developed by Amazon and Google.

The new paper will be presented at next week’s IEEE/RSJ International Conference on Intelligent Robots and Systems in Korea. It was written by Rus alongside three postdocs: lead authors Robert MacCurdy and Jeffrey Lipton, as well as third author Shuguang Li.

Putting a damper on things

There are many reasons for dampers, from controlling the notes of a piano, to keeping car tires on the ground, to protecting structures like radio towers from storms.

The most common damper materials are “viscoelastics” like rubber and plastic that have both solid and liquid qualities. Viscoelastics are cheap, compact, and easy to find, but are generally only commercially available in specific sizes and at specific damping levels because of how time-consuming it is to customize them.

The solution, the team realized, was 3-D printing. By being able to deposit materials with different mechanical properties into a design, 3-D printing allows users to “program” material to their exact needs for every single part of an object.

“It’s hard to customize soft objects using existing fabrication methods, since you need to do injection moulding or some other industrial process,” says Lipton. “3-D printing opens up more possibilities and lets us ask the question, ‘can we make things we couldn’t make before?”

Using a standard 3-D printer, the team used a solid, a liquid, and a flexible rubber-like material called TangoBlack+ to print both the cube and its skins. The PVM process is related to Rus’ previous 3-D printed robotics work, with an inkjet depositing droplets of different material layer-by-layer and then using UV light to solidify the non-liquids.

The cube robot includes a rigid body, two motors, a microcontroller, battery, and inertial measurement unit sensors. Four layers of looped metal strip serve as the springs that propel the cube.    

“By combining multiple materials to achieve properties that are outside the range of the base material, this work pushes the envelope of what’s possible to print,” says Hod Lipson, a professor of engineering at Columbia University and co-author of “Fabricated: The New World of 3-D Printing.” “On top of that, being able to do this in a single print-job raises the bar for additive manufacturing.”

Rus says that PVMs could have many other protective uses, including shock-absorbing running shoes and headgear. By damping the motion brought about by robots’ motors, for example, PVMs are not only able to protect sensitive parts like cameras and sensors, but can also actually make the robots easier to control.

“Being able to program different regions of an object has important implications for things like helmets,” says MacCurdy. “You could have certain parts made of materials that are comfortable for your head to rest on, and other shock-absorbing materials for the sections that are most likely to be impacted in a collision.”

This work was supported by a grant from the National Science Foundation.

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Benoit Forget: Unraveling complexities of nuclear reactors

In order to devise new designs for safer, more efficient nuclear reactors, it is essential to be able to simulate the reactors’ performance at a very high level of detail. But because the nuclear reactions taking place in these reactor cores are quite complex, such simulations can strain the capabilities of even the most advanced supercomputer systems.

That’s a challenge that Benoit Forget has been tackling throughout his research career: how to provide efficient, high-fidelity simulations on modern computing architectures, and thus enable the development of the next generation of reactors.

Addressing those challenges has earned Forget tenure in MIT’s Department of Nuclear Science and Engineering, where he is now an associate professor.

Forget grew up in the small town of Temiscaming in the province of Quebec, Canada. His father was the principal of the local high school and his mother was a teacher there. “My mom was my French, history, and geography teacher,” he recalls. His graduating class had about 20 students.

“Science was always second-nature to me since I was a kid,” he says. “I spent a lot of time just tinkering around, breaking stuff apart and building it back up.” He also had a very supportive science teacher in high school, he says, who encouraged him to explore.

He began studying engineering at the École Polytechnique de Montréal, where he earned a BS in chemical engineering and an MS in energy engineering, and he did an internship at Hydro-Quebec, the local utility, which had a single nuclear power plant at the time.

It was during those first few years in Montréal that Forget developed his interest in nuclear engineering. “That’s when I had my first modern physics class and studied quantum mechanics, and that’s when I got hooked and wanted to study nuclear engineering. … I had a very good professor who introduced us to some of these concepts,” he says. From that one initial class, Forget made the decision to pursue this area of study.

“The [relatively small] amount of energy in a chemical reaction compared to the energy in one fission event is quite remarkable,” he says. “If you want to produce a lot of power quickly with little fuel or waste, this is the way to do it. So that made it my career choice.”

Forget moved to the United States to work on his PhD in nuclear engineering at Georgia Tech. He received the degree in 2006 and then spent a year and a half working at Idaho National Laboratory, before accepting an appointment at MIT. His wife, an aerospace engineer who received her doctorate a week prior to his, took a job at the MITRE Corporation, allowing them to begin their jobs in the Boston area at the same time. The couple now has a three-year-old son, Thomas, who “keeps us very busy,” Forget says.

Since arriving at MIT, Forget has concentrated on developing new ways of streamlining the complex software needed to simulate the vast numbers of random interactions that take place inside a nuclear reactor core, in order to better understand how to develop new generations of improved reactor architectures.

His team, the MIT Computational Reactor Physics Group, consists of two faculty members (he and Kord Smith, the KEPCO Professor of Nuclear Science and Engineering), 15-20 graduate students, and between five and 10 undergraduates. They “focus on modeling and simulation of the nuclear reactor itself — the physics that describes what goes on inside a nuclear reactor, how heat is being generated, where it’s being deposited, and how we extract that heat from the system,” Forget says.

“We focus primarily on the neutron and photon transport in the core, which is essentially the source of the fission reaction — we want to know precisely how much power is being produced where, so we can stay below the temperature limits, the material limits, and control everything else that goes on inside the reactor.” But even using the most efficient, streamlined computer code, simulating the operation of a whole plant for just one instant in time can take 100,000 CPU-hours, he says.

Currently, there are a lot of computer models, developed over the last half-century, that simulate the present generation of nuclear reactors. “These codes perform very well for the current generation,” he says. “But in the near future, there’s a lot of interest in looking at advanced reactors, new concepts, new designs, new materials — all designed to have more inherent safety, better economics, better fuel utilization. All of these cannot necessarily rely on the methods of the past. We’re going to need some more advanced methodologies.”

Since it’s impractical to build test reactors for every new concept, “we rely much more on high-fidelity modeling and simulation,” he says. “We’re still going to need experiments, but we want to design better experiments, so that they provide better information at lesser cost.” That’s where his team’s expertise comes into play. Among other projects, the researchers have developed two large pieces of software, called OpenMC and OpenMOC, which are both open-source packages available to anyone.

One of these code packages, OpenMC, is based on Monte Carlo simulations — a statistical technique for simulating complex systems in which random events play a significant role, by generating vast numbers of simulations that each involve slight variations on the others. The system Forget and his team have developed uses new approaches made possible by massively parallel computing and distributed computation. “Now we end up with a new paradigm for modern architectures in hardware, where we can do a lot of calculations directly” that used to require huge lookup tables of precomputed data, he says. And as a result, the team can more precisely capture the details of the physics, while actually streamlining the computations.

“We kind of bridge a gap between fundamental physics and high-performance computing. We dig a little bit deeper, and try to reformulate and use more fundamental physical representations,” he says. As they develop the models, he hopes to be able to simulate both long-term and short-term transients in addition to current steady state capabilities. Ultimately, “the goal is to be able to simulate a whole reactor, over its full lifetime, with as much detail as possible, for all possible operating conditions,” he says.

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