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  • richardmitnick 11:12 am on October 9, 2019 Permalink | Reply
    Tags: "A new way to corrosion-proof thin atomic sheets", , , , , Nuclear Science, , Ultrathin coating could protect 2D materials from corrosion enabling their use in optics and electronics.   

    From MIT News: “A new way to corrosion-proof thin atomic sheets” 

    MIT News

    From MIT News

    October 4, 2019
    David L. Chandler

    This diagram shows an edge-on view of the molecular structure of the new coating material. The thin layered material being coated is shown in violet at bottom, and the ambient air is shown as the scattered molecules of oxygen and water at the top. The dark layer in between is the protective material, which allows some oxygen (red) through, forming an oxide layer below that provides added protection. Illustration courtesy of the researchers.

    Ultrathin coating could protect 2D materials from corrosion, enabling their use in optics and electronics.

    A variety of two-dimensional materials that have promising properties for optical, electronic, or optoelectronic applications have been held back by the fact that they quickly degrade when exposed to oxygen and water vapor. The protective coatings developed thus far have proven to be expensive and toxic, and cannot be taken off.

    Now, a team of researchers at MIT and elsewhere has developed an ultrathin coating that is inexpensive, simple to apply, and can be removed by applying certain acids.

    The new coating could open up a wide variety of potential applications for these “fascinating” 2D materials, the researchers say. Their findings are reported this week in the journal PNAS, in a paper by MIT graduate student Cong Su; professors Ju Li, Jing Kong, Mircea Dinca, and Juejun Hu; and 13 others at MIT and in Australia, China, Denmark, Japan, and the U.K.

    Research on 2D materials, which form thin sheets just one or a few atoms thick, is “a very active field,” Li says. Because of their unusual electronic and optical properties, these materials have promising applications, such as highly sensitive light detectors. But many of them, including black phosphorus and a whole category of materials known as transition metal dichalcogenides (TMDs), corrode when exposed to humid air or to various chemicals. Many of them degrade significantly in just hours, precluding their usefulness for real-world applications.

    “It’s a key issue” for the development of such materials, Li says. “If you cannot stabilize them in air, their processability and usefulness is limited.” One reason silicon has become such a ubiquitous material for electronic devices, he says, is because it naturally forms a protective layer of silicon dioxide on its surface when exposed to air, preventing further degradation of the surface. But that’s more difficult with these atomically thin materials, whose total thickness could be even less than the silicon dioxide protective layer.

    There have been attempts to coat various 2D materials with a protective barrier, but so far they have had serious limitations. Most coatings are much thicker than the 2D materials themselves. Most are also very brittle, easily forming cracks that let through the corroding liquid or vapor, and many are also quite toxic, creating problems with handling and disposal.

    The new coating, based on a family of compounds known as linear alkylamines, improves on these drawbacks, the researchers say. The material can be applied in ultrathin layers, as little as 1 nanometer (a billionth of a meter) thick, and further heating of the material after application heals tiny cracks to form a contiguous barrier. The coating is not only impervious to a variety of liquids and solvents but also significantly blocks the penetration of oxygen. And, it can be removed later if needed by certain organic acids.

    “This is a unique approach” to protecting thin atomic sheets, Li says, that produces an extra layer just a single molecule thick, known as a monolayer, that provides remarkably durable protection. “This gives the material a factor of 100 longer lifetime,” he says, extending the processability and usability of some of these materials from a few hours up to months. And the coating compound is “very cheap and easy to apply,” he adds.

    In addition to theoretical modeling of the molecular behavior of these coatings, the team made a working photodetector from flakes of TMD material protected with the new coating, as a proof of concept. The coating material is hydrophobic, meaning that it strongly repels water, which otherwise would diffuse into the coating and dissolve away a naturally formed protective oxide layer within the coating, leading to rapid corrosion.

    The application of the coating is a very simple process, Su explains. The 2D material is simply placed into bath of liquid hexylamine, a form of the linear alkylamine, which builds up the protective coating after about 20 minutes, at a temperature of 130 degrees Celsius at normal pressure. Then, to produce a smooth, crack-free surface, the material is immersed for another 20 minutes in vapor of the same hexylamine.

    “You just put the wafer into this liquid chemical and let it be heated,” Su says. “Basically, that’s it.” The coating “is pretty stable, but it can be removed by certain very specific organic acids.”

    The use of such coatings could open up new areas of research on promising 2D materials, including the TMDs and black phosphorous, but potentially also silicene, stanine, and other related materials. Since black phosphorous is the most vulnerable and easily degraded of all these materials, that’s what the team used for their initial proof of concept.

    The new coating could provide a way of overcoming “the first hurdle to using these fascinating 2D materials,” Su says. “Practically speaking, you need to deal with the degradation during processing before you can use these for any applications,” and that step has now been accomplished, he says.

    The team included researchers in MIT’s departments of Nuclear Science and Engineering, Chemistry, Materials Science and Engineering, Electrical Engineering and Computer Science, and the Research Laboratory of Electronics, as well as others at the Australian National University, the University of Chinese Academy of Sciences, Aarhus University in Denmark, Oxford University, and Shinshu University in Japan. The work was supported by the Center for Excitonics and the Energy Frontier Research Center funded by the U.S. Department of Energy, and by the National Science Foundation, the Chinese Academy of Sciences, the Royal Society, the U.S. Army Research Office through the MIT Institute for Soldier Nanotechnologies, and Tohoku University.

    See the full article here .

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  • richardmitnick 3:34 pm on December 26, 2014 Permalink | Reply
    Tags: , Nuclear Science   

    From LANL: “Los Alamos conducts important hydrodynamic experiment in Nevada” 

    Los  Alamos Lab
    Los Alamos National Laboratory

    September 8, 2014
    Kevin N. Roark
    Communications Office
    (505) 665-9202

    Los Alamos National Laboratory has successfully fired the latest in a series of experiments at the Nevada National Security Site (NNSS).

    “Leda is an integrated experiment that provides important surrogate hydrodynamic materials data in support of the Laboratory’s stewardship of the U. S. nuclear deterrent,” said Bob Webster, Associate Director for Weapons Physics.

    Technicians at the Nevada National Security Site make final adjustments to the “Leda” experimental vessel in the “Zero Room” at the underground U1a facility.

    Technicians at the Nevada National Security Site move the experiment in a specially designed container from the Device Assembly Facility.

    The experiment, conducted on Aug. 12, 2014, consisted of a plutonium surrogate material and high explosives to implode a “weapon-relevant geometry,” according to Webster.

    Hydrodynamic experiments such as Leda involve non-nuclear surrogate materials that mimic many of the properties of nuclear materials. Hydrodynamics refers to the physics involved when solids, under extreme conditions, begin to mix and flow like liquids. Other hydrodynamic experiments conducted at NNSS use small amounts of nuclear material, and are called “sub-critical” because they do not contain enough material to cause a nuclear explosion.

    “This experiment ultimately enhances confidence in our ability to predictively model and assess weapon performance in the absence of full-scale underground nuclear testing,” said Webster. These experiments with surrogate materials provide a principle linkage with scaled/full-scale hydrodynamic tests, the suite of prior underground nuclear tests, and scaled plutonium experiments.

    “Experiments like Leda are key to enhancing predictive confidence, challenging next-generation weapon designers, and enhancing our capability to underwrite options for managing the stockpile,” said Charlie Nakhleh, Theoretical Design Division Leader.

    Such hydrodynamic and sub-critical experiments are one of the most useful multi-disciplinary technical activities that exercise the Laboratory’s manufacturing capabilities, tests scientific judgment, and enhances the competency of the Nevada workforce in areas of formality of underground and nuclear operations.

    Immediately following the experiment, conducted at NNSS’s U1a underground complex in collaboration with NSTec and supported by Sandia National Laboratories, Los Alamos scientists and technicians reported a 100 percent data return.

    “Multiple diagnostics that captured the hydrodynamic and implosion processes included pit and case velocimetry, dual-axis x-ray radiography, dynamic surface imaging, optical and electrical monitors of the high-explosive drive as well as detonator performance, and very accurate overall system cross-timing,” said Mark Chadwick, Program Director for Science Campaigns in the weapons physics directorate. “The experiment was operated within expected parameters, including temperature control, and was performed within the required safety and security specifications.”

    Scientists will now study the data in detail and compare with pre-shot predictions. The resulting findings will help assess the confidence weapon designers have in their ability to predict weapon-relevant physics.

    The successful execution of the Leda experiment enables the follow-on sub-critical experiment series, nicknamed Lyra, to be conducted in 2015. Lyra and other related experiments are an essential component in the NNSA’s Science Campaigns and Plutonium Sustainment Programs to support the technical basis for confidence in the nation’s nuclear deterrent, and to support future stockpile stewardship.

    Video of the fully contained experiment can be viewed here.

    See the full article here.

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  • richardmitnick 8:12 am on December 26, 2014 Permalink | Reply
    Tags: , , Nuclear Science   

    From NYT: “E.P.A. Wrestles With Role of Nuclear Plants in Carbon Emission Rules” 

    New York Times

    The New York Times

    DEC. 25, 2014

    Trying to write a complicated formula to cut carbon emissions, the Environmental Protection Agency thinks it has found a magic number: 5.8.

    The agency is trying to complete a rule governing carbon emissions from power plants, and among the most complicated and contentious issues is how to treat existing nuclear power plants. Many of them are threatened with shutdowns because cheap natural gas has made their reactors uncompetitive.

    A reactor under construction at the Vogtle power plant in Waynesboro, Ga. Cheap natural gas is challenging the nuclear industry. Credit John Bazemore/Associated Press

    The agency’s proposal gave an odd mathematical formula for evaluating nuclear plants’ contribution to carbon emissions. It said that 5.8 percent of existing nuclear capacity was at risk of being shut for financial reasons, and thus for states with nuclear reactors, keeping them running would earn a credit of 5.8 percent toward that state’s carbon reduction goal.

    Since receiving tens of thousands of comments on the proposal, the agency is now reviewing the plan. It must evaluate all comments before it sets a final rule, which it hopes to do by June. That rule, however, is likely to be challenged in court.

    Under the proposed formula, if a state closed a 1,000-megawatt nuclear plant and replaced 5.8 percent of it, or 58 megawatts, with carbon-free electricity, it would be deemed to be “carbon neutral.” The state would reach the benchmark even if the other 942 megawatts of power generated came from a carbon-emitting source like natural gas combustion.

    Conversely, a state that kept all its nuclear plants open until 2030 could claim a credit for 5.8 percent toward its carbon reduction goal.

    The 5.8 percent figure for nuclear power plants puzzled even opponents of such power sources.

    “It’s a pretty arbitrary number, I’ll grant them that,” said Michael Mariotte, the president of the Nuclear Information and Resource Service, an activist group that is adamantly opposed to anything nuclear. “Replacing 5.8 percent of any power plant is sort of an odd concept,” he said.

    Mr. Mariotte, though, said that some reactors could be retired without driving up carbon emissions. “We’re not convinced that a lot of it needs to be replaced; some of it’s just excess power,” he said.

    The proposal prompted the American Nuclear Society to coordinate a letter-writing campaign to persuade the E.P.A. to help the reactors. States should get credit for any actions they take to hold down carbon emissions, said Craig H. Piercy, the Washington representative of the group.

    “A pound of carbon reduced anywhere ought to be treated the same,” he said.

    Still, he said, in the draft rule, the nuclear industry fared better than hydroelectricity, the second-biggest source of carbon-free electricity, which got zero credit.

    Mr. Mariotte of the Nuclear Information and Resource Service and other nuclear opponents appear to be mostly concerned that the reactors, which they regard as unsafe, could get a new lease on life. His group and others sent a letter to the E.P.A. complaining about a related issue: that the draft carbon rule requires that states with reactors under construction continue building them, or face even harder-to-meet carbon targets.

    In fact, the question of where to draw the baseline — that is, the date from which the calculations start — is common to many aspects of the carbon rule.

    Senator Bob Casey Jr., a Pennsylvania Democrat, made a similar point in a letter to the E.P.A., saying that the rule should take into account previous work to promote clean energy sources, and to maintain existing nuclear plants.

    And at Exelon, a Chicago-based company that is considering whether to retire several reactors in the Midwest, Kathleen L. Barron, senior vice president for regulatory affairs, complained at a Washington conference on electricity and carbon, “We’re essentially taken for granted.”

    Assumed in the E.P.A.’s planning is that the five reactors currently under construction in the United States will go online. A twin-reactor Vogtle plant is planned near Augusta, Ga., and another twin-reactor plant is in development in South Carolina. In Tennessee, a reactor that the Tennessee Valley Authority started 40 years ago is almost complete.

    They are each multibillion-dollar projects, and certain to raise electricity prices, but because work began before the rule was proposed, the carbon-cutting goals set by the E.P.A. for those states do not include the reactors.

    A recent blog post at the Brookings Institution, by Philip A. Wallach and Alex Abdun-Nabi, points out that if ground had been broken later on the Vogtle plant, the reactors could have met Georgia’s reduction quota. “If, for some reason, the construction were to end unsuccessfully, Georgia would be in dire straits trying to fulfill the standard E.P.A. has set for it under the assumption of completion.”

    Energy experts inside and outside the nuclear industry said that cutting carbon emissions was worth money, and paying slightly above-market prices to keep a 40-year-old reactor running for 20 more years might cost less, per ton of carbon emission prevented, than building wind or solar plants, or coal plants that capture their carbon dioxide.

    “If you have an actual plant that’s subject to premature retirement, some of the work I’ve done with others says that to keep it running is a very cost-effective way to reduce carbon emissions,” said Mark Chupka, an electricity analyst at the Brattle Group, a consulting firm. And he added, “When a nuclear plant retires, you don’t retire 5.8 percent of the plant.”

    Of using a 5.8 percent figure, he said, “Everybody thinks it’s pretty odd, I think including the E.P.A.”

    Jon B. Wellinghoff, a former chairman of the Federal Energy Regulatory Commission, said in an interview that maintaining the old plants would hold down carbon emissions, and that “if we want to keep them, we’ll probably have to support them.”

    Federal subsidies for wind energy, he said, are “knocking reactors off the system” by driving down energy costs, he said.

    Some traditional environmental groups, though, are reluctant to embrace more credit for existing plants. Daniel A. Lashof, the chief operating officer at NextGen Climate, the environmental advocacy group started by the climate advocate Tom Steyer, argued that the bigger issue was not what should keep running, but what should be built.

    “The problem is a lot of the complaints that existing nuclear plants aren’t getting enough credit from E.P.A.’s proposal basically amount to a request to weaken the rule,” said Mr. Lashof, also a longtime climate expert at the Natural Resources Defense Council, “so it’s nothing more than business as usual.”

    See the full article here.

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  • richardmitnick 3:37 pm on November 7, 2014 Permalink | Reply
    Tags: , , Nuclear Science   

    From INL: “A long journey toward advanced nuclear fuels” 

    INL Labs

    Idaho National Laboratory

    Nov. 7, 2014
    Casey O’Donnell

    This summer, researchers at the U.S. Department of Energy’s Idaho National Laboratory received a long-awaited delivery.

    After years of waiting, a trans-Atlantic voyage and a cross-country trip, a cask containing four experimental irradiated pins of nuclear fuel arrived at INL’s Materials and Fuels Complex in late July. With shipping facilitated by AREVA TN, these pins traveled from the Phénix nuclear reactor in France, where INL researchers had shipped them more than eight years ago.

    A nuclear fuel experiment travelled all the way from France for examination at INL’s Materials and Fuels Complex. Here, employees have opened the shipping cask so the fuel cask can be lifted into the Hot Fuels Examination Facility hot cell.

    The four pins contained advanced metallic and nitride fuels fabricated by INL and Los Alamos National Laboratory, respectively, in 2006. The fuel within the pins holds the final bits of data from an international experiment called FUTURIX-FTA.

    FUTURIX, a collaboration between the U.S. DOE and the French Atomic Energy Commission (CEA), is an important part of INL’s research for DOE’s Fuel Cycle Research & Development program. The “FTA” in the experiment’s name alludes to the French phrase for “Actinide Transmutation Fuels.” In a nuclear sense, transmutation, the act of turning one thing into another, involves re-using certain components of used nuclear fuel. This would maximize the energy received from mined uranium. It would also decrease the quantity of hazardous, extremely long-lived radionuclides ultimately destined for nuclear repositories.

    Upon arriving at INL, the shipping cask was unloaded into the truck lock at INL’s Hot Fuel Examination Facility (HEFE).

    “One goal of the Transmutation Fuels program is to increase the holding capacity of a nuclear fuel repository without increasing the repository’s size,” INL nuclear engineer Heather Chichester said. “To do this, we’re looking at ways to address limits on holding capacity: volume, heat (produced by radioactive decay) and radiotoxicity of used nuclear fuel.”

    Reusing uranium is one way to drastically reduce the volume of used nuclear fuel, Chichester explained. Currently, only about 5 percent of the uranium loaded into a reactor is actually consumed to produce energy. The remaining uranium goes unused. This is because light water reactors, the type of reactor found most predominantly in the world today, can only fission U235, a less plentiful isotope of uranium.

    However, there is a type of reactor that can generate the energy necessary to fission the more abundant U238 as well as the other transuranic isotopes produced during irradiation of nuclear fuel: a fast reactor. About 20 fast reactors exist in the world today.

    “Most of what’s left in used light water reactor fuel—the U238, Pu239 and a few minor actinides—can be reused in a fast reactor,” Chichester said. “This would use our uranium resources more efficiently and reduce the size and heat of the used fuel that has to be disposed.”
    The experiment cask is lifted into the HFEF hot cell through a hatch in its floor.

    Over the past 10 years, the INL Transmutation Fuels team has tested dozens of different fuel compositions that mimic what recycled used nuclear fuel could look like. They are searching for the fuel composition that offers the best results on both ends: efficient energy production in a fast reactor and reduced waste disposal in a nuclear repository.

    So where does FUTURIX come in?

    “These fuels are intended for use in a fast reactor, but we don’t have a fast reactor available for testing in the U.S.,” Chichester explained. “So we’ve been running experiments under modified conditions in ATR (INL’s Advanced Test Reactor). We believe that the modifications we’ve made reproduce most of the important aspects of the environment inside a fast reactor, but we needed to confirm that.”

    To validate their ATR experiments, INL researchers sent four FUTURIX-FTA fuel pins to France to be irradiated in the Phénix Fast Reactor. The scientists also irradiated four identical pins under the modified ATR conditions. After irradiation of the FUTURIX-FTA pins in Phénix was completed, the four pins were stored in a hot cell in France for several years before being shipped back to INL in July.

    Employees used manipulators to place the experiment cask in the hot cell, where the cask will be opened so examination of the fuel samples can begin.
    Now that they’ve returned to INL, researchers will perform detailed examinations of both sets of pins. By comparing the ATR-irradiated pins with those from the French fast reactor, researchers will be able to deduce whether ATR experiments can adequately recreate fast reactor fuel behavior.

    Researchers hope the conditions experienced by these fuels in the French fast reactor will line up with the conditions created for the identical fuels tested in ATR. This would signify that the ATR experiments accurately recreate fast reactor fuel behavior. If so, INL researchers can continue to use their ATR experiments to study new fuels and advance the goals of the Transmutation Fuels program.

    “Hopefully, the FUTURIX-FTA experiment will validate the work we’ve been doing with ATR for the Transmutation Fuels program,” Chichester said. “That’s why finally getting a chance to examine these fuel pins is such a big deal.”

    See the full article here.

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  • richardmitnick 3:49 pm on October 17, 2014 Permalink | Reply
    Tags: , , Nuclear Science,   

    From ANL: “Protons hog the momentum in neutron-rich nuclei” 

    News from Argonne National Laboratory

    October 17, 2014
    Kandice Carter, Jefferson Lab Public Affairs, 757-269-7263, kcarter@jlab.org
    or Jared Sagoff, Argonne National Laboratory communications office, 630-252-5549, media@anl.gov.

    Like dancers swirling on the dance floor with bystanders looking on, protons and neutrons that have briefly paired up in the nucleus have higher-average momentum, leaving less for non-paired nucleons. Using data from nuclear physics experiments carried out at the Department of Energy’s Thomas Jefferson National Accelerator Facility, researchers have now shown for the first time that this phenomenon exists in nuclei heavier than carbon, including aluminum, iron and lead.

    Research has shown that protons and neutrons that have briefly paired up in the nucleus have higher-average momentum, which allows a greater fraction of the protons than neutrons to have high momentum in relatively neutron-rich nuclei, such as carbon, aluminum, iron and lead. This result is contrary to long-accepted theories large nuclei and has implications for ultra-cold atomic gas systems and neutron stars.

    The phenomenon also surprisingly allows a greater fraction of the protons than neutrons to have high momentum in these relatively neutron-rich nuclei, which is contrary to long-accepted theories of the nucleus and has implications for ultra-cold atomic gas systems and neutron stars. The results were published online by the journal Science, on the Science Express website.

    The research builds on earlier work featured in Science that found that protons and neutrons in light nuclei pair up briefly in the nucleus, a phenomenon called a short-range correlation. Nucleons prefer pairing up with nucleons of a different type (proton preferred neutrons to other protons) by 20 to 1, and nucleons involved in a short-range correlation carry higher momentum than unpaired ones.

    Using data from an experiment conducted in 2004, the researchers were able to identify high-momentum nucleons involved in short-range correlations in heavier nuclei. In that experiment, led by Argonne physicist Kawtar Hafidi, the Jefferson Lab Continuous Electron Beam Accelerator Facility produced a 5.01 GeV beam of electrons to probe the nuclei of carbon, aluminum, iron and lead. The outgoing electrons and high-momentum protons were measured.

    “We found this dominance of proton-neutron pairs in the nuclei we studied. What’s striking is this pair-dominance all the way to lead,” says Doug Higinbotham, a staff scientist at Jefferson Lab and a lead coauthor on the paper.

    Then the researchers compared the momenta of protons versus neutrons in these nuclei. According to the Pauli exclusion principle, certain like particles can’t have the same momentum state. So, if you have a bunch of neutrons together, some will have low momentum, and others will have high momentum; the more neutrons you have, the more high-momentum neutrons you would see, as they fill up higher and higher momentum states.

    But according to Higinbotham, that expected picture is not what the researchers found when they measured high-momentum protons in neutron-rich nuclei.

    “What this paper is saying is the reverse, that the protons actually have the higher-average momentum. And it’s because they’ve all paired up with neutrons,” Higinbotham says. “It’s like a dance with too many girls (neutrons) and only a few boys (protons). Those boys are dancing their little hearts out, because there aren’t very many of them. So the average proton momentum is going to be higher than the average neutron momentum, because it’s mostly the neutrons that are sitting there, doing nothing, with nothing to pair up with, except themselves.”

    Higinbotham notes that the neutrons may also pair up briefly with other neutrons in short-range correlations and protons with other protons. However, these like-particle brief pairings occur once for roughly every 20 unlike-particle brief pairings.

    Now, the researchers hope to extend these new findings to other, similar systems, such as the quarks in nucleons and atoms in cold gases. According to Or Hen, a graduate student at Tel Aviv University in Israel and the paper’s lead author, he and his colleagues are already reaching out to other researchers.

    “We expect that this will also happen in ultra-cold atomic gas systems. And we’re having meetings with those researchers. If they find the same phenomenon, then we can use the flexibility of their experimental systems to go to extreme cases of very hard-to-study nuclear systems, such as the large imbalances of protons and neutrons that you can find in neutron stars,” Or said.

    To further that goal, Misak Sargsian, a lead coauthor and professor at Florida International University, said he’s extending this work into his own theoretical calculations of neutron stars.

    “Think of a neutron star like it’s a huge nucleus, where you have ten times more neutrons than protons. The effect should be very, very profound for neutron stars. So this opens up a new direction for research,” Sargsian said.

    According to Lawrence Weinstein, a lead coauthor and eminent scholar and professor at Old Dominion University in Norfolk, Va., the scientists would also like to continue their studies of the pairs.

    “We’d like to measure a lot more aspects of how protons and neutrons pair up in nuclei. So we know not just protons prefer neutrons, but how are the pairs behaving, in detail,” he said.

    This new result was made possible by an initiative funded by a grant from the U.S. Department of Energy and led by Weinstein and Sargsian, as well as Mark Strikman, a distinguished professor at Penn State, and Sebastian Kuhn, a professor and eminent scholar at Old Dominion University. The data-mining initiative consisted of re-analyzing experimental data from completed experiments in an attempt to glean new information that previously had not been considered or was missed. A collaboration of more than 140 researchers from more than 40 institutions and nine countries contributed to the result. Researchers at two U.S. Department of Energy national labs, Jefferson Lab and Argonne National Lab, participated in the research.

    Argonne physicist Kawtar Hafidi led the experiment that first collected the data back in 2003. “That data was so unique that we’ve been able to extract all kinds of information on several different areas of nuclear physics since then,” she said. She chairs the group, the CEBAF Large Acceptance Spectrometer collaboration nuclear physics working group, that oversees the review and release of scientific results from the data taken by that experiment.

    “This is excellent work that helps validate our theoretical picture of nuclear structure,” said Robert Wiringa, an Argonne physicist whose theoretical work is cited in the paper.

    The paper was published online by the journal Science, at the Science Express web site, on Thursday, 16 October, 2014. See http://www.sciencexpress.org, and also http://www.aaas.org. Science and Science Express are published by the AAAS, the science society, the world’s largest general scientific organization.

    This work was supported by the U.S. Department of Energy’s Office of Science (Office of Nuclear Physics), the U.S. National Science Foundation, Israel Science Foundation, Chilean Comisión Nacional de Investigación Científica y Technológica, French Centre National de la Recherche Scientifique and Commissariat a l’Energie Atomique, French-American Cultural Exchange, Italian Istituto Nazionale di Fisica Nucleare, National Research Foundation of Korea and the U.K.’s Science and Technology Facilities Council. CEBAF is a DOE Office of Science User Facility.

    See the full article here.

    Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

    The Advanced Photon Source at Argonne National Laboratory is one of five national synchrotron radiation light sources supported by the U.S. Department of Energy’s Office of Science to carry out applied and basic research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels, provide the foundations for new energy technologies, and support DOE missions in energy, environment, and national security. To learn more about the Office of Science X-ray user facilities, visit http://science.energy.gov/user-facilities/basic-energy-sciences/.

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  • richardmitnick 5:26 pm on August 25, 2014 Permalink | Reply
    Tags: , , Nuclear Science   

    From Argonne Lab: “Argonne, KAERI to develop prototype nuclear reactor “ 

    News from Argonne National Laboratory

    August 25, 2014
    No Writer Credit

    The U.S. Department of Energy’s Argonne National Laboratory has teamed up with the Korea Atomic Energy Research Institute (KAERI) to develop the Prototype Generation-IV Sodium-cooled Fast Reactor (PGSFR). KAERI’s Sodium-cooled Fast Reactor Development Agency has provided $6.78 million funding to date for Argonne’s contributions through a Work-for-Others contract.

    Argonne will support the Korean Atomic Energy Research Institute’s development of a Prototype Generation-IV Sodium-cooled Fast Reactor that incorporates an innovative metal fuel developed at Argonne. The fuel’s inherent safety potential was demonstrated in landmark tests conducted on the Experimental Breeder Reactor-II. Image credit: KAER I.

    Jong Kyung Kim, President of KAERI, visited Argonne today to execute the memorandum of understanding between KAERI and Argonne for a broad field of technical cooperation on nuclear science and technology, including the PGSFR project. “The technical cooperation between KAERI and Argonne plays a critical role in advancing cutting-edge technologies in nuclear energy,” said Argonne Director Peter Littlewood.

    The PGSFR is a 400 MWth, 150 MWe advanced sodium-cooled fast reactor that incorporates many innovative design features; in particular, metal fuel, which enables inherent safety characteristics. With Argonne support, KAERI is developing the reactor system while the Korean engineering and construction firm KEPCO E&C is designing the balance of the plant. The PGSFR Project aims to secure the Korean licensing authority’s design approval by the end of 2020, and the schedule calls for PGSFR to be commissioned by the end of 2028.

    The metal fuel technology base was developed at Argonne in the 1980s and ‘90s; its inherent safety potential was demonstrated in the landmark tests conducted on the Experimental Breeder Reactor-II in April 1986. They demonstrated the safe shutdown and cooling of the reactor without operator action following a simulated loss-of-cooling accident.

    “We are very excited about our collaboration on the PGSFR,” said Mark Peters, Argonne’s Associate Laboratory Director for Energy Engineering and Systems Analysis. “PGSFR is the world’s first new fast reactor that will use the technology developed at Argonne, and also the world’s first fast reactor that exploits inherent safety characteristics to prevent severe accidents.”

    The Argonne-KAERI collaboration on PGSFR was established following the U.S. Government authorization of the 10 CFR Part 810 request to transfer sodium-cooled fast reactor and low-enriched uranium fuel technology to the Republic of Korea.

    See the full article here.

    Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

    The Advanced Photon Source at Argonne National Laboratory is one of five national synchrotron radiation light sources supported by the U.S. Department of Energy’s Office of Science to carry out applied and basic research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels, provide the foundations for new energy technologies, and support DOE missions in energy, environment, and national security. To learn more about the Office of Science X-ray user facilities, visit http://science.energy.gov/user-facilities/basic-energy-sciences/.

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  • richardmitnick 8:12 am on June 16, 2014 Permalink | Reply
    Tags: , Nuclear Science   

    From Sandia Lab: “Moly 99 reactor using Sandia design could lead to U.S. supply of isotope to track disease “ 

    Sandia Lab

    June 16, 2014
    Nancy Salem

    An Albuquerque startup company has licensed a Sandia National Laboratories technology that offers a way to make molybdenum-99, a key radioactive isotope needed for diagnostic imaging in nuclear medicine, in the United States. Known as moly 99, it is made in aging nuclear reactors outside the country, and concerns about future shortages have been in the news for years.

    Eden Radioisotopes LLC was founded last year and licensed the Sandia moly 99 reactor conceptual design in November. It hopes to build the first U.S. reactor for making the isotope and become a global supplier.

    Dick Coats, right, Eden Radioisotopes’ chief technology officer and a retired Sandia National Laboratories researcher, talks to Sandia nuclear engineer John Ford at the Annular Core Research Reactor, where they helped develop a molybdenum-99 reactor concept in the 1990s. Eden recently licensed the technology with the goal of producing a U.S. supply of moly 99 for use in nuclear medicine. (Photo by Randy Montoya)

    “One of the pressing reasons for starting this company is the moly 99 shortages that are imminent in the next few years,” said Chris Wagner, Eden’s chief operating officer and a 30-year veteran of the medical-imaging industry. “We really feel this is a critical time period to enter the market and supply replacement capacity for what is going offline.”

    Moly 99 is the precursor for the radioactive isotope technetium-99m, used extensively in medical diagnostic tests because it emits a gamma ray that can be tracked in the body, letting physicians create images of the spread of a disease. And it decays quickly so patients are exposed to little radiation.

    Moly 99 is made in commercial nuclear reactors using weapon-grade uranium and 50 to 100 megawatts of power. Neutrons bombard the uranium-235 target. The uranium fissions and produces a moly 99 atom about 6 percent of the time. Moly 99 is extracted from the reactor through a chemical process in a hot-cell facility and used by radiopharmaceutical manufacturers worldwide to produce moly 99/technetium-99m generators. The moly 99, with a 66-hour half-life, decays to technetium-99m, with a six-hour half-life. The generators are shipped to hospitals, clinics and radiopharmacies, which make individual unit doses for use in a wide variety of patient-imaging procedures.

    “It’s a $4 billion a year market,” Wagner said. “There are 30 million diagnostic procedures done worldwide each year, and 80 percent use technetium-99m. More than 50 percent of the procedures are done in the United States, and 60 percent of those are cardiac-related. This issue is very important to U.S. health care because there is no domestic production supplier on U.S. soil.”

    Unreliable reactors cause moly shortages

    The world’s five primary moly 99 production reactors are often closed for repairs, causing periodic shortages that can last months, Wagner said. Two of the largest could either stop producing moly 99 or be decommissioned in the next 10 years. “They represent more than 60 percent of the global supply,” Wagner said. “There is a new reactor due in France, but even if the two go offline and new replacement capacity comes on, Eden still predicts a 20 to 30 percent global shortage to meet today’s demand, and greater future shortages as demand rises.”

    A search has been on for a number of years for a way to make moly 99 in the United States without using weapon-grade uranium. Several companies have explored new kinds of reactors and different methods to produce the isotope but none are in commercial production. “Eden would be the first reactor in the U.S. specific for medical isotope production,” Wagner said. “We feel that science wise, this has the most potential for success in the market.”

    Dick Coats, Eden’s chief technology officer, is a retired Sandia Labs researcher who helped develop the moly 99 reactor concept in the 1990s. Based on technology developed in the Department of Energy-funded Sandia medical isotope production program of that era, the team created a reactor concept tailored to the business of producing moly 99. “This reactor is very small, less than 2 megawatts in power, about a foot-and-a-half in diameter and about the same height, but very efficient,” Coats said.

    The reactor sits in a pool of cooling water 28 to 30 feet deep. It has an all-target core of low-enriched uranium — less than 20 percent U-235 — fuel elements. “The targets are irradiated and every one can be pulled out and processed for moly 99. The entire core is available for moly 99 production,” Coats said. “Every fission that occurs produces moly. The reactor’s only purpose is medical isotope production. This is what is new and unique. Nobody thought about approaching it that way.”

    Eden reactor could meet demand

    Sandia’s Ed Parma, who was on the original team, said the world demand for moly 99 can be met with a small, all-target reactor processed every week. He said larger reactors aren’t cost effective because they use so much power to drive the targets. “They’re using 150 megawatts to drive a 1 megawatt system,” he said. “When you add in fuel costs, operations, maintenance, it’s hard to make money.”

    He said there has never been a reactor system designed just to make moly 99. “They all started as something else,” he said. “Our design is scaled down just for the production of moly. The reactor is only the size you need. It’s more efficient and economically viable.”

    Eden is raising investment capital to meet initial costs through production, estimated at about $75 million.

    It hopes to be in production in about four years. During that time it will build the reactor and facilities and seek a license from the Nuclear Regulatory Commission, and Food and Drug Administration approval of the manufacturing process. Wagner said the preferred location is Hobbs, N.M., which has a labor force familiar with nuclear work due to the nearby URENCO USA uranium enrichment facility. Eden would employ about 140 people.

    “Our intent is not to make something just for the United States,” Wagner said. “We will be U.S.-based so U.S. health care has domestic coverage. But our production capacity will be enough to meet the entire global demand.”

    Business team has nuclear medicine experience

    On the business side, two companies provide 100 percent of U.S. production and distribution of moly 99/technetium-99m generators: Mallinckrodt Pharmaceuticals in Missouri and Lantheus Medical Imaging in Massachusetts. Wagner is a former Mallinckrodt vice president and Eden advisory board member Peter Card is a former Lantheus vice president. On the technical side, Coats works at Eden with Milt Vernon, another retired Sandia researcher who worked on the technology. “We have all the bases covered to be successful,” Wagner said.

    Bob Westervelt of Sandia’s licensing group said the lab pursued an exclusive license for the technology. “We didn’t want multiple people trying to build it,” he said. “We wanted one company that could actually commercialize it.”

    The licensing department advertised the opportunity last summer, and interested parties had to demonstrate they had the financial resources and technical know-how to build the reactor and get regulatory and environmental approvals.

    “There were 10 responses and only one, Eden, came with a full package proposal,” Westervelt said. Eden was given an exclusive license for the term of the patent, which is pending.

    “It’s very exciting to be part of a project that could be commercialized,” Parma said. “I think this is the future. There’s no doubt in my mind.”

    See the full article here.

    Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

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  • richardmitnick 4:45 pm on November 25, 2013 Permalink | Reply
    Tags: , , , , Nuclear Science, ,   

    From PPPL- “Multinational achievement: PPPL collaborates on record fusion plasma in tokamak in China” 

    November 25, 2013
    John Greenwald

    A multinational team led by Chinese researchers in collaboration with U.S. and European partners has successfully demonstrated a novel technique for suppressing instabilities that can cut short the life of controlled fusion reactions. The team, headed by researchers at the Institute of Plasma Physics in the Chinese Academy of Sciences (ASIPP), combined the new technique with a method that the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) has developed for protecting the walls that surround the hot, charged plasma gas that fuels fusion reactions.

    Interior view of EAST tokamak(Photo by Institute of Plasma Physics, Chinese Academy of Sciences )

    The record-setting results of the tests, conducted on the Experimental Advanced Superconducting Tokamak (EAST) in Hefei, China, could mark a key step in the worldwide effort to develop fusion as a clean and abundant source of energy for generating electricity. “This is a very good example of multinational collaboration on EAST,” said ASIPP Director Jiangang Li. “I very much appreciate the effort of our collaborators.”

    First reporting the results was a paper published online in the November issue of the journal Nature Physics. U.S co-authors included PPPL physicists Jon Menard and Rajesh Maingi, who headed the wall-conditioning effort, and General Atomics physicist Gary Jackson, a plasma-control expert who helped draft the paper.

    The findings could hold particular promise for developers of future fusion facilities such as ITER, the international experiment under construction in France. Controlling instabilities that erupt at the edge of the plasma will be crucial to the success of the huge donut-shaped ITER tokamak, which is designed to demonstrate the feasibility of fusion power.

    The EAST experiments set a record for the duration of what is called an H-mode, or high-confinement plasma — the type that will be employed in ITER and other future tokamaks. To achieve this duration, the EAST team beamed what are known as “lower hybrid wave current drive” microwaves into the plasma. The antenna-launched beams reshaped the magnetic field lines confining the plasma and suppressed instabilities at the edge of the gas near the interior walls of the tokamak. Controlling these fast-growing instabilities, called “edge localized modes” (ELMs), produced a record life span of more than 30 seconds for the H-mode plasma.

    These results suggested a potent new method for suppressing ELMS to create an extended, or long-pulse, plasma. Many methods already exist. Among them are the use of external magnetic coils to alter the field lines that enclose the plasma, and the injection of pellets of deuterium fuel into the plasma during experiments.

    Contributing to the EAST results was the PPPL-designed wall treatment, which coated the plasma-facing walls of the tokamak with the metal lithium and inserted lithium granules into experiments to keep the coating fresh. The silvery metal absorbed stray plasma particles and kept impurities from entering the core of the plasma and halting fusion reactions. “When lithium has been used to coat the walls of fusion devices, higher plasma temperature, pressure, and confinement have been achieved,” PPPL physicists Menard and Maingi said in an interview.

    “This was good physics,” Jackson of General Atomics said of the experiments, noting that long-pulse plasmas will be required for fusion power plants to generate electricity.

    Combining microwave beams for ELMs suppression with the advanced lithium wall treatment could thus provide a fruitful new direction for fusion-energy development. This combination of techniques, the Nature Physics paper said, offers “an attractive regime for high-performance, long-pulse operations.”

    See the full article here.

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

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  • richardmitnick 7:24 pm on November 21, 2013 Permalink | Reply
    Tags: , , , , , Nuclear Science   

    From Berkeley Lab: “Searching for Cosmic Accelerators Via IceCube” 

    Berkeley Lab

    Berkeley Lab Researchers Part of an International Hunt

    November 21, 2013
    Lynn Yarris (510) 486-5375 lcyarris@lbl.gov

    In our universe there are particle accelerators 40 million times more powerful than the Large Hadron Collider (LHC) at CERN. Scientists don’t know what these cosmic accelerators are or where they are located, but new results being reported from “IceCube,” the neutrino observatory buried at the South Pole, may show the way. These new results should also erase any doubts as to IceCube’s ability to deliver on its promise.

    IceCube is a neutrino observatory whose detectors are buried more than a mile below the surface of the South Pole. (Photo by Emanuel Jacobi of the National Science Foundation)

    “The IceCube Collaboration has announced the observation of 28 extremely high energy events that constitute the first solid evidence for astrophysical neutrinos from outside our solar system,” says Spencer Klein, a senior scientist with Lawrence Berkeley National Laboratory (Berkeley Lab) and a long-time member of the IceCube Collaboration. “These 28 events include two of the highest energy neutrinos ever reported, which have been named Bert and Ernie.”

    Lisa Gerhardt and Spencer Klein with an IceCube Digital Optical Module (DOM). IceCube employs 5,160 DOMs to detect the Cherenkov radiation emitted by high-energy neutrino events in the ice. (Photo by Roy Kaltschmidt)

    The new results from IceCube, which were published in the journal Science, provide experimental confirmation that somewhere in the universe, something is accelerating particles to energies above 50 trillion electron volts (TeV) and, in the cases of Bert and Ernie, exceeding one quadrillion electron volts (PeV). By comparison, the LHC accelerates protons to approximately four TeV in each of its beams. While not telling scientists what cosmic accelerators are or where they’re located, the IceCube results do provide scientists with a compass that can help guide them to the answers.

    The IceCube observatory consists of 5,160 basketball-sized light detectors called Digital Optical Modules (DOMs), which were conceived and largely designed at Berkeley Lab. The DOMS are suspended along 86 strings that are embedded in a cubic kilometer of clear ice starting one and a half kilometers beneath the Antarctic surface. Out of the trillions of neutrinos that pass through the ice each day, a couple of hundred will collide with oxygen nuclei, yielding the blue light of Cherenkov radiation that IceCube’s DOMs detect.

    Cherenkov radiation glowing in the core of the Advanced Test Reactor

    “Each of IceCube’s DOMs was designed to be a mini-computer server that you can log onto and download data from, or upload software to,” says Robert Stokstad, a senior scientist with Berkeley Lab’s Nuclear Science Division who led the development of the DOMs and was one of the original proponents of IceCube. “It is rewarding to see how well they are performing.”

    The 28 high-energy neutrinos reported in Science by the IceCube Collaboration were found in data collected from May 2010 to May 2012. In analyzing more recent data, Berkeley Lab’s Lisa Gerhardt discovered another event that was almost double the energy of Bert and Ernie. Dubbed “Big Bird,” this new event was presented by Klein at the International Cosmic-Ray Conference.

    See the full article here.

    A U.S. Department of Energy National Laboratory Operated by the University of California

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  • richardmitnick 4:09 pm on June 24, 2013 Permalink | Reply
    Tags: , , , Nuclear Science   

    From Livermore Lab: “Livermorium and Flerovium join the periodic table of elements” 

    Lawrence Livermore National Laboratory

    Anne M Stark, LLNL, (925) 422-9799, stark8@llnl.gov

    “The International Union of Pure and Applied Chemistry (IUPAC) today officially approved new names for elements 114 and 116, the latest heavy elements to be added to the periodic table.

    No image credit

    Scientists of the Lawrence Livermore National Laboratory (LLNL)-Dubna collaboration proposed the names as Flerovium for element 114, with the symbol Fl, and Livermorium for element 116, with the symbol Lv, late last year.

    Flerovium (atomic symbol Fl) was chosen to honor Flerov Laboratory of Nuclear Reactions, where superheavy elements, including element 114, were synthesized. Georgiy N. Flerov (1913-1990) was a renowned physicist who discovered the spontaneous fission of uranium and was a pioneer in heavy-ion physics. He is the founder of the Joint Institute for Nuclear Research. In 1991, the laboratory was named after Flerov — Flerov Laboratory of Nuclear Reactions (FLNR).

    Livermorium (atomic symbol Lv) was chosen to honor Lawrence Livermore National Laboratory (LLNL) and the city of Livermore, Calif. A group of researchers from the Laboratory, along with scientists at the Flerov Laboratory of Nuclear Reactions, participated in the work carried out in Dubna on the synthesis of superheavy elements, including element 116. (Lawrencium — Element 103 — was already named for LLNL’s founder E.O. Lawrence.)

    The IUPAC states Livermorium was chosen because over the years scientists at Livermore have been involved in many areas of nuclear science: the investigation of fission properties of the heaviest elements, including the discovery of bimodal fission, and the study of prompt gamma-rays emitted from fission fragments following fission; the investigation of isomers and isomeric levels in many nuclei; and the investigation of the chemical properties of the heaviest elements.

    ‘These names honor not only the individual contributions of scientists from these laboratories to the fields of nuclear science, heavy element research, and superheavy element research, but also the phenomenal cooperation and collaboration that has occurred between scientists in these two countries,’ said Bill Goldstein, associate director of LLNL’s Physical and Life Sciences Directorate.

    See the full article here.

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