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    Investigating materials for safe, secure nuclear power

    Michael Short came to MIT in the fall of 2001 as an 18-year-old first-year who grew up in Boston’s North Shore. He immediately felt at home, so much so that he’s never really left. It’s not that Short has no interest in exploring the world beyond the confines of the Institute, as he is an energetic and venturesome fellow. It’s just that almost everything he hopes to achieve in his scientific career can, in his opinion, be best pursued at this university.

    Last year — after collecting four MIT degrees and joining the faculty of the Department of Nuclear Science and Engineering (NSE) in 2013 — he was promoted to the status of tenured associate professor.

    Short’s enthusiasm for MIT began early in high school when he attended weekend programs that were mainly taught by undergraduates. “It was a program filled with my kind of people,” he recalls. “My high school was very good, but this was at a different level — at the level I was seeking and hoping to achieve. I felt more at home here than I did in my hometown, and the Saturdays at MIT were the highlight of my week.” He loved his four-year experience as an MIT undergraduate, including the research he carried out in the Uhlig Corrosion Laboratory, and he wasn’t ready for it to end.

    After graduating in 2005 with two BS degrees (one in NSE and another in materials science and engineering), he took on some computer programming jobs and worked half time in the Uhlig lab under the supervision of Ronald Ballinger, a professor in both NSE and the Department of Materials Science and Engineering. Short soon realized that computer programming was not for him, and he started graduate studies with Ballinger as his advisor, earning a master’s and a PhD in nuclear science and engineering in 2010.

    Even as an undergraduate, Short was convinced that nuclear power was essential to our nation’s (and the world’s) energy future, especially in light of the urgent need to move toward carbon-free sources of power. During his first year, he was told by Ballinger that the main challenge confronting nuclear power was to find materials, and metals in particular, that could last long enough in the face of radiation and the chemically destructive effects of corrosion.

    Those words, persuasively stated, led him to his double major.  “Materials and radiation damage have been at the core of my research ever since,” Short says. “Remarkably, the stuff I started studying in my first year of college is what I do today, though I’ve extended this work in many directions.”

    Corrosion has proven to be an unexpectedly rich subject. “The traditional view is to expose metals to various things and see what happens — ‘cook and look,’ as it’s called,” he says. “A lot of folks view it that way, but it’s actually much more complex. In fact, some members of our own faculty don’t want to touch corrosion because it’s too complicated, too dirty. But that’s what I like about it.”

    In a 2020 paper published in Nature Communications, Short, his student Weiyue Zhou, and other colleagues made a surprising discovery. “Most people think radiation is bad and makes everything worse, but that’s not always the case,” Short maintains. His team found a specific set of conditions under which a metal (a nickel-chromium alloy) performs better when it is irradiated while undergoing corrosion in a molten salt mixture. Their finding is relevant, he adds, “because these are the conditions under which people are hoping to run the next generation of nuclear reactors.” Leading candidates for alternatives to today’s water-cooled reactors are molten salt and liquid metal (specifically liquid lead and sodium) cooled reactors. To this end, Short and his colleagues are currently carrying out similar experiments involving the irradiation of metal alloys immersed in liquid lead.

    Meanwhile, Short has pursued another multiyear project, trying to devise a new standard to serve as “a measurable unit of radiation damage.” In fact, these were the very words he wrote on his research statement when applying for his first faculty position at MIT, although he admits that he didn’t know then how to realize that goal. But the effort is finally paying off, as Short and his collaborators are about to submit their first big paper on the topic. He’s found that you can’t reduce radiation damage to a single number, which is what people have tried to do in the past, because that’s too simple. Instead, their new standard relates to the density of defects — the number of radiation-induced defects (or unintentional changes to the lattice structure) per unit volume for a given material.

    “Our approach is based on a theory that everyone agrees on — that defects have energy,” Short explains. However, many people told him and his team that the amount of energy stored within those defects would be too small to measure. But that just spurred them to try harder, making measurements at the microjoule level, at the very limits of detection.

    Short is convinced that their new standard will become “universally useful, but it will take years of testing on many, many materials followed by more years of convincing people using the classic method: Repeat, repeat, repeat, making sure that each time you get the same result. It’s the unglamorous side of science, but that’s the side that really matters.”

    The approach has already led Short, in collaboration with NSE proliferation expert Scott Kemp, into the field of nuclear security. Equipped with new insights into the signatures left behind by radiation damage, students co-supervised by Kemp and Short have devised methods for determining how much fissionable material has passed through a uranium enrichment facility, for example, by scrutinizing the materials exposed to these radioactive substances. “I never thought my preliminary work on corrosion experiments as an undergraduate would lead to this,” Short says.

    He has also turned his attention to “microreactors” — nuclear reactors with power ratings as small as a single megawatt, as compared to the 1,000-megawatt behemoths of today. Flexibility in the size of future power plants is essential to the economic viability of nuclear power, he insists, “because nobody wants to pay $10 billion for a reactor now, and I don’t blame them.”

    But the proposed microreactors, he says, “pose new material challenges that I want to solve. It comes down to cramming more material into a smaller volume, and we don’t have a lot of knowledge about how materials perform at such high densities.” Short is currently conducting experiments with the Idaho National Laboratory, irradiating possible microreactor materials to see how they change using a laser technique, transient grating spectroscopy (TGS), which his MIT group has had a big hand in advancing.

    It’s been an exhilarating 20 years at MIT for Short, and he has even more ambitious goals for the next 20 years. “I’d like to be one of those who came up with a way to verify the Iran nuclear deal and thereby helped clamp down on nuclear proliferation worldwide,” he says. “I’d like to choose the materials for our first power-generating nuclear fusion reactors. And I’d like to have influenced perhaps 50 to 100 former students who chose to stay in science because they truly enjoy it.

    “I see my job as creating scientists, not science,” he says, “though science is, of course, a convenient byproduct.” More

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    A material difference

    Eesha Khare has always seen a world of matter. The daughter of a hardware engineer and a biologist, she has an insatiable interest in what substances — both synthetic and biological — have in common. Not surprisingly, that perspective led her to the study of materials.

    “I recognized early on that everything around me is a material,” she says. “How our phones respond to touches, how trees in nature to give us both structural wood and foldable paper, or how we are able to make high skyscrapers with steel and glass, it all comes down to the fundamentals: This is materials science and engineering.”

    As a rising fourth-year PhD student in the MIT Department of Materials Science and Engineering (DMSE), Khare now studies the metal-coordination bonds that allow mussels to bind to rocks along turbulent coastlines. But Khare’s scientific enthusiasm has also led to expansive interests from science policy to climate advocacy and entrepreneurship.

    A material world

    A Silicon Valley native, Khare recalls vividly how excited she was about science as a young girl, both at school and at myriad science fairs and high school laboratory internships. One such internship at the University of California at Santa Cruz introduced her to the study of nanomaterials, or materials that are smaller than a single human cell. The project piqued her interest in how research could lead to energy-storage applications, and she began to ponder the connections between materials, science policy, and the environment.

    As an undergraduate at Harvard University, Khare pursued a degree in engineering sciences and chemistry while also working at the Harvard Kennedy School Institute of Politics. There, she grew fascinated by environmental advocacy in the policy space, working for then-professor Gina McCarthy, who is currently serving in the Biden administration as the first-ever White House climate advisor.

    Following her academic explorations in college, Khare wanted to consider science in a new light before pursuing her doctorate in materials science and engineering. She deferred her program acceptance at MIT in order to attend Cambridge University in the U.K., where she earned a master’s degree in the history and philosophy of science. “Especially in a PhD program, it can often feel like your head is deep in the science as you push new research frontiers, but I wanted take a step back and be inspired by how scientists in the past made their discoveries,” she says.

    Her experience at Cambridge was both challenging and informative, but Khare quickly found that her mechanistic curiosity remained persistent — a realization that came in the form of a biological material.

    “My very first master’s research project was about environmental pollution indicators in the U.K., and I was looking specifically at lichen to understand the social and political reasons why they were adopted by the public as pollution indicators,” Khare explains. “But I found myself wondering more about how lichen can act as pollution indicators. And I found that to be quite similar for most of my research projects: I was more interested in how the technology or discovery actually worked.”

    Enthusiasm for innovation

    Fittingly, these bioindicators confirmed for her that studying materials at MIT was the right course. Now Khare works on a different organism altogether, conducting research on the metal-coordination chemical interactions of a biopolymer secreted by mussels.

    “Mussels secrete this thread and can adhere to ocean walls. So, when ocean waves come, mussels don’t get dislodged that easily,” Khare says. “This is partly because of how metal ions in this material bind to different amino acids in the protein. There’s no input from the mussel itself to control anything there; all the magic is in this biological material that is not only very sticky, but also doesn’t break very readily, and if you cut it, it can re-heal that interface as well! If we could better understand and replicate this biological material in our own world, we could have materials self-heal and never break and thus eliminate so much waste.”

    To study this natural material, Khare combines computational and experimental techniques, experimentally synthesizing her own biopolymers and studying their properties with in silico molecular dynamics. Her co-advisors — Markus Buehler, the Jerry McAfee Professor of Engineering in Civil and Environmental Engineering, and Niels Holten-Andersen, professor of materials science and engineering — have embraced this dual-approach to her project, as well as her abundant enthusiasm for innovation.

    Khare likes to take one exploratory course per semester, and a recent offering in the MIT Sloan School of Management inspired her to pursue entrepreneurship. These days she is spending much of her free time on a startup called Taxie, formed with fellow MIT students after taking the course 15.390 (New Enterprises). Taxie attempts to electrify the rideshare business by making electric rental cars available to rideshare drivers. Khare hopes this project will initiate some small first steps in making the ridesharing industry environmentally cleaner — and in democratizing access to electric vehicles for rideshare drivers, who often hail from lower-income or immigrant backgrounds.

    “There are a lot of goals thrown around for reducing emissions or helping our environment. But we are slowly getting physical things on the road, physical things to real people, and I like to think that we are helping to accelerate the electric transition,” Khare says. “These small steps are helpful for learning, at the very least, how we can make a transition to electric or to a cleaner industry.”

    Alongside her startup work, Khare has pursued a number of other extracurricular activities at MIT, including co-organizing her department’s Student Application Assistance Program and serving on DMSE’s Diversity, Equity, and Inclusion Council. Her varied interests also have led to a diverse group of friends, which suits her well, because she is a self-described “people-person.”

    In a year where maintaining connections has been more challenging than usual, Khare has focused on the positive, spending her spring semester with family in California and practicing Bharatanatyam, a form of Indian classical dance, over Zoom. As she looks to the future, Khare hopes to bring even more of her interests together, like materials science and climate.

    “I want to understand the energy and environmental sector at large to identify the most pressing technology gaps and how can I use my knowledge to contribute. My goal is to figure out where can I personally make a difference and where it can have a bigger impact to help our climate,” she says. “I like being outside of my comfort zone.” More

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    Reducing emissions by decarbonizing industry

    A critical challenge in meeting the Paris Agreement’s long-term goal of keeping global warming well below 2 degrees Celsius is to vastly reduce carbon dioxide (CO2) and other greenhouse gas emissions generated by the most energy-intensive industries. According to a recent report by the International Energy Agency, these industries — cement, iron and steel, chemicals — account for about 20 percent of global CO2 emissions. Emissions from these industries are notoriously difficult to abate because, in addition to emissions associated with energy use, a significant portion of industrial emissions come from the process itself.

    For example, in the cement industry, about half the emissions come from the decomposition of limestone into lime and CO2. While a shift to zero-carbon energy sources such as solar or wind-powered electricity could lower CO2 emissions in the power sector, there are no easy substitutes for emissions-intensive industrial processes.

    Enter industrial carbon capture and storage (CCS). This technology, which extracts point-source carbon emissions and sequesters them underground, has the potential to remove up to 90-99 percent of CO2 emissions from an industrial facility, including both energy-related and process emissions. And that begs the question: Might CCS alone enable hard-to-abate industries to continue to grow while eliminating nearly all of the CO2 emissions they generate from the atmosphere?

    The answer is an unequivocal yes in a new study in the journal Applied Energy co-authored by researchers at the MIT Joint Program on the Science and Policy of Global Change, MIT Energy Initiative, and ExxonMobil.

    Using an enhanced version of the MIT Economic Projection and Policy Analysis (EPPA) model that represents different industrial CCS technology choices — and assuming that CCS is the only greenhouse gas emissions mitigation option available to hard-to-abate industries — the study assesses the long-term economic and environmental impacts of CCS deployment under a climate policy aimed at capping the rise in average global surface temperature at 2 C above preindustrial levels.

    The researchers find that absent industrial CCS deployment, the global costs of implementing the 2 C policy are higher by 12 percent in 2075 and 71 percent in 2100, relative to policy costs with CCS. They conclude that industrial CCS enables continued growth in the production and consumption of energy-intensive goods from hard-to-abate industries, along with dramatic reductions in the CO2 emissions they generate. Their projections show that as industrial CCS gains traction mid-century, this growth occurs globally as well as within geographical regions (primarily in China, Europe, and the United States) and the cement, iron and steel, and chemical sectors.

    “Because it can enable deep reductions in industrial emissions, industrial CCS is an essential mitigation option in the successful implementation of policies aligned with the Paris Agreement’s long-term climate targets,” says Sergey Paltsev, the study’s lead author and a deputy director of the MIT Joint Program and senior research scientist at the MIT Energy Initiative. “As the technology advances, our modeling approach offers decision-makers a pathway for projecting the deployment of industrial CCS across industries and regions.”

    But such advances will not take place without substantial, ongoing funding.

    “Sustained government policy support across decades will be needed if CCS is to realize its potential to promote the growth of energy-intensive industries and a stable climate,” says Howard Herzog, a co-author of the study and senior research engineer at the MIT Energy Initiative.

    The researchers also find that advanced CCS options such as cryogenic carbon capture (CCC), in which extracted CO2 is cooled to solid form using far less power than conventional coal- and gas-fired CCS technologies, could help expand the use of CCS in industrial settings through further production cost and emissions reductions.

    The study was supported by sponsors of the MIT Joint Program and by ExxonMobil through its membership in the MIT Energy Initiative. More

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    Manipulating magnets in the quest for fusion

    “You get the high field, you get the performance.”

    Senior Research Scientist Brian LaBombard is summarizing what might be considered a guiding philosophy behind designing and engineering fusion devices at MIT’s Plasma Science and Fusion Center (PSFC). Beginning in 1972 with the Alcator A tokamak, through Alcator C (1978) and Alcator C-Mod (1991), the PSFC has used magnets with high fields to confine the hot plasma in compact, high-performance tokamaks. Joining what was then the Plasma Fusion Center as a graduate student in 1978, just as Alcator A was finishing its run, LaBombard is one of the few who has worked with each iteration of the high-field concept. Now he has turned his attention to the PSFC’s latest fusion venture, a fusion energy project called SPARC.

    Designed in collaboration with MIT spinoff Commonwealth Fusion Systems (CFS), SPARC employs novel high temperature superconducting (HTS) magnets at high-field to achieve fusion that will produce net energy gain. Some of these magnets will wrap toroidally around the tokamak’s doughnut-shaped vacuum chamber, confining fusion reactions and preventing damage to the walls of the device.

    The PSFC has spent three years researching, developing, and manufacturing a scaled version of these toroidal field (TF) coils — the toroidal field model coil, or TFMC. Before the TF coils can be built for SPARC, LaBombard and his team need to test the model coil under the conditions that it will experience in this tokamak.

    HTS magnets need to be cooled in order to remain superconducting, and to be protected from the heat generated by current. For testing, the TFMC will be enclosed in a cryostat, cooled to the low temperatures needed for eventual tokamak operation, and charged with current to produce magnetic field. How the magnet responds as the current is provided to the coil will determine if the technology is in hand to construct the 18 TF coils for SPARC.

    A history of achievement

    That LaBombard is part of the PSFC’s next fusion project is not unusual; that he is involved in designing, engineering, and testing the magnets is. Until 2018, when he led the R&D research team for one of the magnet designs being considered for SPARC, LaBombard’s 30-plus years of celebrated research had focused on other areas of the fusion question.

    As a graduate student, he gained early acclaim for the research he reported in his PhD thesis. Working on Alcator C, he made groundbreaking discoveries about the plasma physics in the “boundary” region of the tokamak, between the edge of the fusing core and the wall of the machine. With typical modesty, LaBombard credits some of his success to the fact that the topic was not well-studied, and that Alcator C provided measurements not possible on other machines.

    “People knew about the boundary, but nobody was really studying it in detail. On Alcator C, there were interesting phenomena, such as marfes [multifaceted asymmetric radiation from the edge], being detected for the first time. This pushed me to make boundary layer measurements in great detail that no one had ever seen before. It was all new territory, so I made a big splash.”

    That splash established him as a leading researcher in the field of boundary plasmas. After a two-year turn at the University of California at Los Angeles working on a plasma-wall test facility called PISCES, LaBombard, who grew up in New England, was happy to return to MIT to join the PSFC’s new Alcator C-Mod project.

    Over the next 28 years of C-Mod’s construction phase and operation, LaBombard continued to make groundbreaking contributions to understanding tokamak edge and divertor plasmas, and to design internal components that can survive the harsh conditions and provide plasma control — including C-Mod’s vertical target plate divertor and a unique divertor cryopump system. That experience led him to conceive of the “X-point target divertor” for handling extreme fusion power exhaust and to propose a national Advanced Divertor tokamak eXperiment (ADX) to test such ideas.

    All along, LaBombard’s true passion was in creating revolutionary diagnostics to unfold boundary layer physics and in guiding graduate students to do the same: an Omegatron, to measure impurity concentrations directly in the boundary plasma, resolved by charge-to-mass ratio; fast-scanning Langmuir-Mach probes to measure plasma flows; a Shoelace Antenna to provide insight into plasma fluctuations at the edge; the invention of a Mirror Langmuir Probe for the real-time measurements of plasma turbulence at high bandwidth.

    Switching sides

    His expertise established, he could have continued this focus on the edge of the plasma through collaborations with other laboratories and at the PSFC. Instead, he finds himself on the other side of the vacuum chamber, immersed in magnet design and technology. Challenged with finding an effective HTS magnet design for SPARC, he and his team were able to propose a winning strategy, one that seemed most likely to achieve the compact high field and high performance that PSFC tokamaks have been known for.

    LaBombard is stimulated by his new direction and excited about the upcoming test of the TFMC. His new role takes advantage of his physics background in electricity and magnetism. It also supports his passion for designing and building things, which he honed as high school apprentice to his machinist father and explored professionally building systems for Alcator C-Mod.

    “I view my principal role is to make sure the TF coil works electrically, the way it’s supposed to,” he says. “So it produces the magnetic field without damaging the coil.”

    A successful test would validate the understanding of how the new magnet technology works, and will prepare the team to build magnets for SPARC.

    Among those overseeing the hours of TFMC testing will be graduate students, current and former, reminding LaBombard of his own student days working on Alcator C, and of his years supervising students on Alcator C-Mod.

    “Those students were directly involved with Alcator C-Mod. They would jump in, make things happen — and as a team. This team spirit really enabled everyone to excel.

    “And looking to when SPARC was taking shape, you could see that across the board, from the new folks to the younger folks, they really got engaged by the spirit of Alcator — by recognition of the plasma performance that can be made possible by high magnetic fields.”

    He laughs as he looks to the past and to the future.

    “And they are taking it to SPARC.” More

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    Push to make supply chains more sustainable continues to gain momentum

    Much of the effort to make businesses sustainable centers on their supply chains, which were severely disrupted during the Covid-19 pandemic. Yet, according to new research from the MIT Center for Transportation and Logistics (CTL), supply chain sustainability (SCS) investments hardly slowed, even as the pandemic raged.

    The finding, contained in the 2021 State of Supply Chain Sustainability report, puts companies on notice that they ignore the sustainability of their supply chains at their peril. This is particularly the case for enterprises with a low or moderate commitment to SCS, such as organizations classed as “Low Effort” and “Dreamer” in the new SCS Firm Typology that appears in the report for the first time. 

    The research also highlights the increasing pressure companies are under to devote resources to SCS. This pressure came from various stakeholders last year and suggests that sustainability in supply chains is a business trend, and not a fad.

    CTL publishes the 2021 State of Supply Chain Sustainability report in collaboration with the Council of Supply Chain Management Professionals (CSCMP), a leading professional membership association. This year’s report is sponsored by BlueYonder, C.H. Robinson, KPMG, Intel, and Sam’s Club.

    Sustainability efforts undaunted by Covid-19

    “We believe cooperation between sectors is vital to thoroughly understand the complexity and evolution of sustainability efforts more broadly,” says David Correll, CTL research scientist. “Our work with CSCMP and our sponsors helps us to embed this essential research and its findings within the context of the real-life practice of supply chain management.”

    The research included a large-scale international survey of supply chain professionals with over 2,400 respondents — more than double the number received for the previous report. The survey was conducted in late 2020. In addition, 21 in-depth executive interviews were completed, and relevant news items, social media content, and reports were analyzed for the report.

    More than 80 percent of survey respondents claimed the pandemic had no impact or increased their firms’ commitments to SCS: Eighty-three percent of the executives interviewed said that Covid-19 had either accelerated SCS activity or, at the very least, increased awareness and brought urgency to this growing field.

    The pressure to support sustainability in supply chains came from multiple sources, both internal and external, but increased the most among investors and industry associations. Internally, company executives were standout champions of SCS.

    Although there are many approaches to investing in SCS, interest in human rights protection and worker welfare, along with energy savings and renewable energy, increased significantly last year. Supplier development was the most common mechanism used by firms to deliver on their SCS promises.

    Increasing investment, some speed bumps

    Given the momentum behind SCS, the future will likely bring more investment in this increasingly important area of supply chain management. And practitioners — who bring deep domain expertise and well-rounded views of enterprises to the table — will become more influential as sustainability advocates.

    But there are some formidable obstacles to overcome, too. For example, it is notable that most of the momentum behind SCS appeared to come from large (1,000-plus employees) and very large (10,000-plus employees) companies covered by the research. Small- to medium-sized enterprises were far less committed, and more work is needed to bring them into the fold through a better understanding of the barriers they face.

    A broader concern is that more attention from stakeholders — notably consumers, investors, and regulators — will bring more scrutiny of firms’ SCS track records, and less tolerance of token efforts to make supply chains sustainable. Improved supply chain transparency and disclosure are critical to firms’ responses, the report suggests.

    Some high-profile issues, such as combating social injustices and climate change mitigation, will continue to stoke the pressure on companies to invest in meaningful SCS initiatives. It follows that the connection between companies’ SCS performance and their profitability is likely to strengthen over the next few years.

    Will companies follow through?

    As companies grapple with these issues, they will face some difficult decisions. For example, the chief operating officer of a consumer goods company interviewed for the report described operating through pandemic constraints as a “moral calculus” where some sustainability commitments had to be temporarily sacrificed to achieve others. Such a calculus will likely challenge many companies as they juggle their responses to SCS demands. A key question is to ascertain the degree to which companies’ recent net-zero commitments will translate into effective SCS actions over the next few years.

    The CTL and CSCMP research teams are laying the groundwork for the 2022 State of Supply Chain Sustainability report. This annual status report aims to help practitioners and the industry to make more effective and informed sustainability decisions. The questionnaire for next year’s report will open in September. More