Tagged: ITER Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 12:29 pm on July 6, 2018 Permalink | Reply
    Tags: ELISE, , ITER, MIPP   

    From Max Planck Institute for Plasma Physics: IPP’s ELISE test rig achieves first ITER objective 

    MPIPP bloc

    From Max Planck Institute for Plasma Physics

    July 04, 2018
    Isabella Milch

    Neutral-particle heating for ITER / Fast-hydrogen-particle beam for plasma heating.

    The heating beam in the ELISE test rig at Max Planck Institute for Plasma Physics (IPP) at Garching near Munich has attained the values needed for ITER: It can maintain for 1,000 seconds a particle beam composed of negatively charged hydrogen ions with the current strength of 23 amperes desired by ITER.
    ELISE is serving to prepare one of the heating methods that are to bring the plasma of the international ITER test reactor to several million degrees. The core piece is a novel high-frequency ion source developed at IPP that produces the high-energy particle beam.

    1
    One of the accelerator grids that get the hydrogen atoms in the ELISE ion source to the right velocity. The particle beam is extracted as individual beams through 640 small apertures in the grid surface of about a square metre. Photo: IPP

    The international ITER (Latin for ‘the way’) test reactor, now being built in France as a world-wide cooperation, is to demonstrate that a fusion fire supplying energy is possible.

    Iter experimental tokamak nuclear fusion reactor that is being built next to the Cadarache facility in Saint Paul les-Durance south of France

    Like the sun, a future fusion power plant is to derive energy from fusion of atomic nuclei. The fuel, viz. a hydrogen plasma, has to be confined without wall contact in a magnetic field cage and be heated to ignition temperatures exceeding 100 million degrees. ITER is to produce 500 megawatts of fusion power, this being ten times as much as needed beforehand to heat the plasma.

    About half of this plasma heating will be provided by the neutral-particle heating: Fast hydrogen atoms injected through the magnetic field cage into the plasma transfer their energy to the plasma particles by way of collisions. For this purpose, an ion source produces from hydrogen gas charged hydrogen ions that are accelerated by high voltage and finally re-neutralised so that, as fast hydrogen atoms, they can penetrate into the plasma unhampered by the magnetic field.

    This method enables present-day heating systems, e.g. that for IPP’s ASDEX Upgrade fusion device at Garching, to bring the plasma to a multiple of the sun’s temperature at the click of a button. The ITER large-scale device, however, presents higher requirements: For example, the particle beams have to be much thicker and the individual particles be much faster than hitherto so that they can penetrate the voluminous ITER plasma to a sufficient depth. Two particle beams with cross-sections about the size of an ordinary door are to feed 16.5 megawatts of heating power into the ITER plasma. ITER will thus greatly surpass the particle beams used in today’s fusion devices, which make do with cross-sections about the size of a dinner plate and much lower velocity.

    Therefore, instead of the positively charged ions used hitherto, which cannot be effectively neutralised at high energies, for ITER it is necessary to use negatively charged ions, which are extremely fragile. A high-frequency ion source developed for the purpose at IPP was incorporated in the ITER design. At the end of 2012 IPP was given a contract for further development and adaptions to ITER requirements.

    The ELISE (Extraction from a Large Ion Source Experiment) test rig constitutes a source half as large as that for ITER later. ELISE generates an ion beam with a cross-sectional area of about a square metre. The increased format made it necessary to revise the previous technical solutions for the heating method (see PI 2/2015). ELISE has advanced step by step to new orders of magnitude. “Now we are able to produce the desired 23-ampere particle beam of negatively charged hydrogen ions, stable, homogeneous and lasting 1,000 seconds”, states Professor Dr Ursel Fantz, head of IPP’s ITER Technology and Diagnostics division. “The gas pressure in the source and the quantity of electrons retained also meet ITER’s requirements”. It was only the current density of the ion beam that was not quite attained, this being due to the limited power capability of the high-voltage supply available.

    Where does it go from here?

    Now that ELISE has attained the ion current required by ITER with ordinary hydrogen it is time to tackle the second part of the task and produce ion beams from deuterium, the heavy isotope of hydrogen, albeit not just for 1,000 seconds, but for a whole hour. The system in the original size will be investigated by Italy’s fusion institute, ENEA, in Padua, who will collaborate with IPP. The SPIDER (Source for Production of Ions of Deuterium Extracted from Radio-frequency Plasma) test device was commissioned at Padua in early June. The target data: one-hour pulses with full ITER beam cross-section and 6 megawatts of power in hydrogen and deuterium.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    MPIPP campus

    The Max Planck Institute of Plasma Physics (Max-Planck-Institut für Plasmaphysik, IPP) is a physics institute for the investigation of plasma physics, with the aim of working towards fusion power. The institute also works on surface physics, also with focus on problems of fusion power.

    The IPP is an institute of the Max Planck Society, part of the European Atomic Energy Community, and an associated member of the Helmholtz Association.

    The IPP has two sites: Garching near Munich (founded 1960) and Greifswald (founded 1994), both in Germany.

    It owns several large devices, namely

    the experimental tokamak ASDEX Upgrade (in operation since 1991)
    the experimental stellarator Wendelstein 7-AS (in operation until 2002)
    the experimental stellarator Wendelstein 7-X (awaiting licensing)
    a tandem accelerator

    It also cooperates with the ITER and JET projects.

    Advertisements
     
  • richardmitnick 1:30 pm on December 30, 2017 Permalink | Reply
    Tags: A.I.P., , , ITER, Lifetime of primary runaway electrons estimated for high-plasma-current fusion devices, ,   

    From AIP: “Lifetime of primary runaway electrons estimated for high-plasma-current fusion devices” 

    AIP Publishing Bloc

    American Institute of Physics

    November 2017
    Meeri Kim

    Analysis of field and collision influence on runaway electrons produced during plasma disruptions provides insight into lifetime trends.

    1
    No image caption or credit.

    For ITER and other high-plasma-current fusion devices, runaway electrons are a matter of concern.

    ITER Tokamak in Saint-Paul-lès-Durance, which is in southern France

    [ITER, way behind schedule and way over budget, is about as good as it gets in the search for Fusion Technology, which has been 30 years away for the last thirty years.]

    These highly accelerated electrons, produced in great numbers during plasma disruptions, can form a runaway beam that hits and damages the wall of the machine.

    A recent U.S. initiative called SCREAM (Simulation Center for Runaway Electron Avoidance and Mitigation) combines theoretical models with advanced simulation and analysis to address the runaway problem. As part of SCREAM, two physicists used kinetic analysis to predict the lifetime of primary runaway electrons, reporting the results in Physics of Plasmas.

    The authors wanted to understand the distribution of primary runaway electrons by taking into account the interplay of three factors: acceleration by electric field, collisions with plasma electrons and ions, and synchrotron losses. Their analysis dealt with the kinetic equation for relativistic electrons in a straight and homogeneous magnetic field, which they were able to simplify and rescale to highlight its similarity features.
    They found that the lifetime of seed runaways increases exponentially with the electric field, with the rate depending on a combination of parameters collectively called “alpha,” that includes the effects of ion charge and synchrotron time scale. For alpha much less than one, the lifetimes can be long when the electric field is only slightly about the renowned Connor-Hastie critical value, when the friction, or drag, on the relativistic electrons from ion collisions becomes energy independent and the electrons can be accelerated continuously. For alpha much larger than one, significantly stronger electric fields are necessary for runaway seed electron survival.

    Long-lived runaway electrons have greater opportunity to multiply via an avalanche effect. Knowing the parameter range that creates long lifetimes will inform ITER researchers about what regimes to avoid in planned experiments.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    AIP Building

    AIP serves a federation of physical science societies in a common mission to promote physics and allied fields.

     
  • richardmitnick 6:02 pm on November 21, 2017 Permalink | Reply
    Tags: , , , , , , ITER, , Plasma-facing material   

    From BNL: “Designing New Metal Alloys Using Engineered Nanostructures” 

    Brookhaven Lab

    Stony Brook University assistant professor Jason Trelewicz brings his research to design and stabilize nanostructures in metals to Brookhaven Lab’s Center for Functional Nanomaterials.

    1
    Materials scientist Jason Trelewicz in an electron microscopy laboratory at Brookhaven’s Center for Functional Nanomaterials, where he characterizes nanoscale structures in metals mixed with other elements.

    Materials science is a field that Jason Trelewicz has been interested in since he was a young child, when his father—an engineer—would bring him to work. In the materials lab at his father’s workplace, Trelewicz would use optical microscopes to zoom in on material surfaces, intrigued by all the distinct features he would see as light interacted with different samples.

    Now, Trelewicz—an assistant professor in the College of Engineering and Applied Sciences’ Department of Materials Science and Chemical Engineering with a joint appointment in the Institute for Advanced Computational Science at Stony Brook University and principal investigator of the Engineered Metallic Nanostructures Laboratory—takes advantage of the much higher magnifications of electron microscopes to see tiny nanostructures in fine detail and learn what happens when they are exposed to heat, radiation, and mechanical forces. In particular, Trelewicz is interested in nanostructured metal alloys (metals mixed with other elements) that incorporate nanometer-sized features into classical materials to enhance their performance. The information collected from electron microscopy studies helps him understand interactions between structural and chemical features at the nanoscale. This understanding can then be employed to tune the properties of materials for use in everything from aerospace and automotive components to consumer electronics and nuclear reactors.

    Since 2012, when he arrived at Stony Brook University, Trelewicz has been using the electron microscopes and the high-performance computing (HPC) cluster at the Center for Functional Nanomaterials (CFN)—a U.S. Department of Energy (DOE) Office of Science User Facility at Brookhaven National Laboratory—to perform his research.

    “At the time, I was looking for ways to apply my idea of stabilizing nanostructures in metals to an application-oriented problem,” said Trelewicz. “I’ve long been interested in nuclear energy technologies, initially reading about fusion in grade school. The idea of recreating the processes responsible for the energy we receive from the sun here on earth was captivating, and fueled my interest in nuclear energy throughout my entire academic career. Though we are still very far away from a fusion reactor that generates power, a large international team on a project under construction in France called ITER is working to demonstrate a prolonged fusion reaction at a large scale.”

    Plasma-facing materials for fusion reactors

    Nuclear fusion—the reaction in which atomic nuclei collide—could provide a nearly unlimited supply of safe, clean energy, like that naturally produced by the sun through fusing hydrogen nuclei into helium atoms. Harnessing this carbon-free energy in reactors requires generating and sustaining a plasma, an ionized gas, at the very high temperatures at which fusion occurs (about six times hotter than the sun’s core) while confining it using magnetic fields. Of the many challenges currently facing fusion reactor demonstrations, one of particular interest to Trelewicz is creating viable materials to build a reactor.

    2
    A model of the ITER tokamak, an experimental machine designed to harness the energy of fusion. A powerful magnetic field is used to confine the plasma, which is held in a doughnut-shaped vessel. Credit: ITER Organization.

    “The formidable materials challenges for fusion are where I saw an opportunity for my research—developing materials that can survive inside the fusion reactor, where the plasma will generate high heat fluxes, high thermal stresses, and high particle and neutron fluxes,” said Trelewicz. “The operational conditions in this environment are among the harshest in which one could expect a material to function.”

    A primary candidate for such “plasma-facing material” is tungsten, because of its high melting point—the highest one among metals in pure form—and low sputtering yield (number of atoms ejected by energetic ions from the plasma). However, tungsten’s stability against recrystallization, oxidation resistance, long-term radiation tolerance, and mechanical performance are problematic.

    Trelewicz thinks that designing tungsten alloys with precisely tailored nanostructures could be a way to overcome these problems. In August, he received a $750,000 five-year award from the DOE’s Early Career Research Program to develop stable nanocrystalline tungsten alloys that can withstand the demanding environment of a fusion reactor. His research is combining simulations that model atomic interactions and experiments involving real-time ion irradiation exposure and mechanical testing to understand the fundamental mechanisms responsible for the alloys’ thermal stability, radiation tolerance and mechanical performance. The insights from this research will inform the design of more resilient alloys for fusion applications.

    In addition to the computational resources they use at their home institution, Trelewicz and his lab group are using the HPC cluster at the CFN—and those at other DOE facilities, such as Titan at Oak Ridge Leadership Computing Facility (a DOE Office of Science User Facility at Oak Ridge National Laboratory)—to conduct large-scale atomistic simulations as part of the project.

    ORNL Cray Titan XK7 Supercomputer

    “The length scales of the structures we want to design into our materials are on the order of a few nanometers to 100 nanometers, and a single simulation can involve up to 10 million atoms,” said Trelewicz. “Using HPC clusters, we can build a system atom-by-atom, representative of the structure we would like to explore experimentally, and run simulations to study the response of that system under various external stimuli. For example, we can fire a high-energy atom into the system and watch what happens to the material and how it evolves, hundreds or thousands of times. Once damage has accumulated in the structure, we can simulate thermal and mechanical forces to understand how defect structure impacts other behavior.”

    These simulations inform the structures and chemistries of experimental alloys, which Trelewicz and his students fabricate at Stony Brook University through high-energy milling. To characterize the nanoscale structure and chemical distribution of the engineered alloys, they extensively use the microscopy facilities at the CFN—including scanning electron microscopes, transmission electron microscopes, and scanning transmission electron microscopes. Imaging is conducted at high resolution and often combined with heating within the microscope to examine in real time how the structures evolve with temperature. Experiments are also conducted at other DOE national labs, such as Sandia through collaboration with materials scientist Khalid Hattar of the Ion Beam Laboratory. Here, students in Trelewicz’s research group simultaneously irradiate the engineered alloys with an ion beam and image them with an electron microscope over the course of many days.

    3
    Trelewicz and his students irradiated a nanostructured tungsten-titanium alloy with high-energy gold ions to explore the radiation tolerance of this novel material.

    “Though this damage does not compare to what the material would experience in a reactor, it provides a starting point to evaluate whether or not the engineered material could indeed address some of the limitations of tungsten for fusion applications,” said Trelewicz.

    Electron microscopy at the CFN has played a key role in an exciting discovery that Trelewicz’s students recently made: an unexpected metastable-to-stable phase transition in thin films of nanostructured tungsten. This phase transition drives an abnormal “grain” growth process in which some crystalline nanostructure features grow very dramatically at the expense of others. When the students added chromium and titanium to tungsten, this metastable phase was completely eliminated, in turn enhancing the thermal stability of the material.

    “One of the great aspects of having both experimental and computational components to our research is that when we learn new things from our experiments, we can go back and tailor the simulations to more accurately reflect the actual materials,” said Trelewicz.

    Other projects in Trelewicz’s research group.

    The research with tungsten is only one of many projects ongoing in the Engineered Metallic Nanostructures Laboratory.

    “All of our projects fall under the umbrella of developing new metal alloys with enhanced and/or multifunctional properties,” said Trelewicz. “We are looking at different strategies to optimize material performance by collectively tailoring chemistry and microstructure in our materials. Much of the science lies in understanding the nanoscale mechanisms that govern the properties we measure at the macroscale.”

    4
    Jason Trelewicz (left) with Olivia Donaldson, who recently graduated with her PhD from Trelewicz’s group, and Jonathan Gentile, a current doctoral student, in front of the scanning electron microscope/focused-ion beam at Stony Brook University’s Advanced Energy Center. Credit: Stony Brook University.

    Through a National Science Foundation CAREER (Faculty Early Career Development Program) award, Trelewicz and his research group are exploring another class of high-strength alloys—amorphous metals, or “metallic glasses,” which are metals that have a disordered atomic structure akin to glass. Compared to everyday metals, metallic glasses are often inherently higher strength but usually very brittle, and it is difficult to make them in large parts such as bulk sheets. Trelewicz’s team is designing interfaces and engineering them into the metallic glasses—initially iron-based and later zirconium-based ones—to enhance the toughness of the materials, and exploring additive manufacturing processes to enable sheet-metal production. They will use the Nanofabrication Facility at the CFN to fabricate thin films of these interface-engineered metallic glasses for in situ analysis using electron microscopy techniques.

    In a similar project, they are seeking to understand how introducing a crystalline phase into a zirconium-based amorphous alloy to form a metallic glass matrix composite (composed of both amorphous and crystalline phases) augments the deformation process relative to that of regular metallic glasses. Metallic glasses usually fail catastrophically because strain becomes localized into shear bands. Introducing crystalline regions in the metallic glasses could inhibit the process by which strain localizes in the material. They have already demonstrated that the presence of the crystalline phase fundamentally alters the mechanism through which the shear bands form.

    Trelewicz and his group are also exploring the deformation behavior of metallic “nanolaminates” that consist of alternating crystalline and amorphous layers, and are trying to approach the theoretical limit of strength in lightweight aluminum alloys through synergistic chemical doping strategies (adding other elements to a material to change its properties).

    5
    Trelewicz and his students perform large-scale atomistic simulations to explore the segregation of solute species to grain boundaries (GBs)—interfaces between grains—in nanostructured alloys, as shown here for an aluminum-magnesium (Al-Mg) system, and its implications for the governing deformation mechanisms. They are using the insights gained through these simulations to design lightweight alloys with theoretical strengths.

    “We leverage resources of the CFN for every project ongoing in my research group,” said Trelewicz. “We extensively use the electron microscopy facilities to look at material micro- and nanostructure, very often at how interfaces are coupled with compositional inhomogeneities—information that helps us stabilize and design interfacial networks in nanostructured metal alloys. Computational modeling and simulation enabled by the HPC clusters at the CFN informs what we do in our experiments.”

    Beyond his work at CFN, Trelewicz collaborates with his departmental colleagues to characterize materials at the National Synchrotron Light Source II—another DOE Office of Science User Facility at Brookhaven.

    BNL NSLS-II


    BNL NSLS II

    “There are various ways to characterize structural and chemical inhomogeneities,” said Trelewicz. “We look at small amounts of material through the electron microscopes at CFN and on more of a bulk level at NSLS-II through techniques such as x-ray diffraction and the micro/nano probe. We combine this local and global information to thoroughly characterize a material and use this information to optimize its properties.”

    Future of next-generation materials

    When he is not doing research, Trelewicz is typically busy with student outreach. He connects with the technology departments at various schools, providing them with materials engineering design projects. The students not only participate in the engineering aspects of materials design but are also trained on how to use 3D printers and other tools that are critical in today’s society to manufacture products more cost effectively and with better performance.

    Going forward, Trelewicz would like to expand his collaborations at the CFN and help establish his research in metallic nanostructures as a core area supported by CFN and, ultimately, DOE, to achieve unprecedented properties in classical materials.

    “Being able to learn something new every day, using that knowledge to have an impact on society, and seeing my students fill gaps in our current understanding are what make my career as a professor so rewarding,” said Trelewicz. “With the resources of Stony Brook University, nearby CFN, and other DOE labs, I have an amazing platform to make contributions to the field of materials science and metallurgy.”

    Trelewicz holds a bachelor’s degree in engineering science from Stony Brook University and a doctorate in materials science and engineering with a concentration in technology innovation from MIT. Before returning to academia in 2012, Trelewicz spent four years in industry managing technology development and transition of harsh-environment sensors produced by additive manufacturing processes. He is the recipient of a 2017 Department of Energy Early Career Research Award, 2016 National Science Foundation CAREER award, and 2015 Young Leaders Professional Development Award from The Minerals, Metals & Materials Society (TMS), and is an active member of several professional organizations, including TMS, the Materials Research Society, and ASM International (the Materials Information Society).

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1

     
  • richardmitnick 7:42 am on October 17, 2017 Permalink | Reply
    Tags: , , ITER, , , SSEN-steady-state electrical network   

    From PPPL: “PPPL completes shipment of electrical components to power site for ITER, the international fusion experiment” 


    PPPL

    October 16, 2017
    Jeanne Jackson DeVoe

    1
    Electrical components procured by PPPL. Pictured clockwise: switchgear, HV protection and control cubicles, resistors, and insulators. (Photo by Photo courtesy of © ITER Organization, http://www.iter.org/)

    The arrival of six truckloads of electrical supplies at a warehouse for the international ITER fusion experiment on Oct. 2 brings to a successful conclusion a massive project that will provide 120 megawatts of power – enough to light up a small city − to the 445-acre ITER site in France.

    ITER Tokamak in Saint-Paul-lès-Durance, which is in southern France

    The Princeton Plasma Physics Laboratory (PPPL), with assistance from the Department of Energy’s Princeton Site Office, headed the $34 million, five-year project on behalf of US ITER to provide three quarters of the components for the steady-state electrical network (SSEN), which provides electricity for the lights, pumps, computers, heating, ventilation and air conditioning to the huge fusion energy experiment. ITER connected the first transformer to France’s electrical grid in March. The European Union is providing the other 25 percent.

    The shipment was the 35th and final delivery of equipment from companies all over the world, including from the United States over the past three years.

    “I think it’s a great accomplishment to finish this,” said Hutch Neilson, head of ITER Fabrication. “The successful completion of the SSEN program is a very important accomplishment both for the US ITER project and for PPPL as a partner in the US ITER project.”

    The six trucks that arrived carried a total of 63 crates of uninterruptible power supply equipment weighing 107 metric tons. The trucks took a seven-hour, 452-mile journey from Gutor UPS and Power Conversion in Wettingen, Switzerland, northwest of Zurich, to an ITER storage facility in Port-Saint-Louis-Du-Rhône, France. The equipment will eventually be used to provide emergency power to critical ITER systems in the event of a power outage.

    “This represents the culmination of a very complex series of technical specifications and global purchases, and we are grateful to the entire PPPL team and their vendors for outstanding commitment and performance”, said Ned Sauthoff, director of the US ITER Project Office at Oak Ridge National Laboratory, where all U.S. contributions to ITER are managed for the U.S. Department of Energy’s Office of Science.

    A device known as a tokamak, ITER will be the largest and most powerful fusion machine in the world. Designed to produce 500 megawatts of fusion power for 50 megawatts of input power, it will be the first fusion device to create net energy – it will get more energy out than is put in. Fusion is the process by which stars like the sun create energy – the fusing of light elements

    A separate electrical system for the pulsed power electrical network (PPEN), procured by China, will power the ITER tokamak.

    The first SSEN delivery in 2014 was among the first plant components to be delivered to the ITER site. The SSEN project is now one of the first U.S. packages to be completed in its entirety, Neilson said. He noted that the final shipment arrived 10 days ahead of PPPL’s deadline.

    In addition to the electrical components, PPPL is also responsible for seven diagnostic instruments and for integrating the instruments inside ITER port plugs. While PPPL is continuing work on an antenna for one diagnostic, most of the diagnostic and port integration work has been put on hold amid uncertainty over U.S. funding for its contributions to ITER.

    The SSEN project was a complex enterprise. PPPL researched potential suppliers, solicited and accepted bids, and oversaw the production and testing of electrical components in 16 separate packages worth a total of about $30 million. The effort involved PPPL engineers, as well as procurement and quality assurance staff members who worked to make sure that the components met ITER specifications and would do exactly what they are supposed to do. “It’s really important that we deliver to ITER equipment that exactly meets the requirements they specify and that it be quality equipment that doesn’t give them trouble down the road,” Neilson said. “So every member of the team makes sure that gets done.”

    Many of the components were for the high-voltage switchyard. A massive transformer procured by PPPL was connected to the French electrical grid in March. PPPL procured and managed the purchase and transportation of the 87-ton transformer and three others, which were built in South Korea by Hyundai Heavy Industries, a branch of the company known for producing cars. =

    The SSEN components came from as close to home as Mount Pleasant, Pennsylvania, to as far away as Turkey, with other components coming from Mexico, Italy, Spain, France, Germany, South Korea and the Netherlands.

    John Dellas, the head of electrical systems and the team leader for the project, has been working on the ITER SSEN project for the entire five years of the program. He traveled to Schweinfurt, Germany, to oversee testing of the control and protection systems for the high-voltage switchyard.

    Dellas took over the project from Charles Neumeyer after Neumeyer became engineering director for the NSTX-U Recovery Project last year. Dellas said Neumeyer deserves most of the credit for the program. “Charlie took the team down to the 10-yard line and I put everything in the end zone,” Dellas said. “I was working with Charlie but Charlie was the quarterback.”

    Neumeyer worked on the project from 2006, when the project was in the planning stages, until 2016. He said he was happy to see the project completed. “It’s very gratifying to see roughly 10 years of work come to a satisfying conclusion under budget and on schedule,” he said.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition


    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

     
  • richardmitnick 6:56 pm on September 26, 2017 Permalink | Reply
    Tags: , , ITER,   

    From PPPL: “Research led by PPPL provides reassurance that heat flux will be manageable in ITER” 


    PPPL

    September 26, 2017
    John Greenwald

    1

    A major issue facing ITER, the international tokamak under construction in France that will be the first magnetic fusion device to produce net energy, is whether the crucial divertor plates that will exhaust waste heat from the device can withstand the high heat flux, or load, that will strike them. Alarming projections extrapolated from existing tokamaks suggest that the heat flux could be so narrow and concentrated as to damage the tungsten divertor plates in the seven-story, 23,000 ton tokamak and require frequent and costly repairs. This flux could be comparable to the heat load experienced by spacecraft re-entering Earth’s atmosphere.

    New findings of an international team led by physicist C.S. Chang of the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) paint a more positive picture. Results of the collaboration, which has spent two years simulating the heat flux, indicate that the width could be well within the capacity of the divertor plates to tolerate.

    Good news for ITER

    “This could be very good news for ITER,” Chang said of the findings, published in August in the journal Nuclear Fusion. “This indicates that ITER can produce 10 times more power than it consumes, as planned, without damaging the divertor plates prematurely.”

    At ITER, spokesperson Laban Coblentz, said the simulations were of great interest and highly relevant to the ITER project. He said ITER would be keen to see experimental benchmarking, performed for example by the Joint European Torus (JET) at the Culham Centre for Fusion Energy in the United Kingdom, to strengthen confidence in the simulation results.

    Joint European Torus, at the Culham Centre for Fusion Energy in the United Kingdom

    Chang’s team used the highly sophisticated XGC1 plasma turbulence computer simulation code developed at PPPL to create the new estimate. The simulation projected a width of 6 millimeters for the heat flux in ITER when measured in a standardized way among tokamaks, far greater than the less-than 1 millimeter width projected through use of experimental data.

    Deriving projections of narrow width from experimental data were researchers at major worldwide facilities. In the United States, these tokamaks were the National Spherical Torus Experiment before its upgrade at PPPL; the Alcator C-Mod facility at MIT, which ceased operations at the end of 2016; and the DIII-D National Fusion Facility that General Atomics operates for the DOE in San Diego.

    4
    National Spherical Torus Experiment at PPPL

    5
    Alcator C-Mod tokamak at MIT

    6
    DIII-D National Fusion Facility, San Diego

    Widely different conditions

    The discrepancy between the experimental projections and simulation predictions, said Chang, stems from the fact that conditions inside ITER will be too different from those in existing tokamaks for the empirical predictions to be valid. Key differences include the behavior of plasma particles within today’s machines compared with the expected behavior of particles in ITER. For example, while ions contribute significantly to the heat width in the three U.S. machines, turbulent electrons will play a greater role in ITER, rendering extrapolations unreliable.

    Chang’s team used basic physics principles, rather than empirical projections based on the data from existing machines, to derive the simulated wider prediction. The team first tested whether the code could predict the heat flux width produced in experiments on the U.S. tokamaks, and found the predictions to be valid.

    Researchers then used the code to project the width of the heat flux in an estimated model of ITER edge plasma. The simulation predicted the greater heat-flux width that will be sustainable within the current ITER design.

    Supercomputers enabled simulation

    Supercomputers made this simulation possible. Validating the code on the existing tokamaks and producing the findings took some 300 million core hours on Titan and Cori, two of the most powerful U.S. supercomputers, housed at the DOE’s Oak Ridge Leadership Computing Facility and the National Energy Research Scientific Computing Center, respectively.

    ORNL Cray XK7 Titan Supercomputer

    NERSC Cray Cori II supercomputer

    A core hour is one processor, or core, running for one hour.

    Researchers from eight U.S. and European institutions collaborated on this research. In addition to PPPL, the institutions included ITER, the Culham Centre for Fusion Energy, the Institute of Atomic and Subatomic Physics at the Technical University of Vienna, General Atomics, MIT, Oak Ridge National Laboratory and Lawrence Livermore National Laboratory.

    Support for this work comes from the DOE Office of Science Offices of Fusion Energy Sciences and Office of Advanced Scientific Computing Research.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition


    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

     
  • richardmitnick 1:05 pm on September 11, 2017 Permalink | Reply
    Tags: , ITER, NSTX-U Tokamak at PPPL,   

    From PPPL: “PPPL has a new interim director and is moving ahead with construction of prototype magnets” 


    PPPL

    September 8, 2017
    Jeanne Jackson DeVoe

    1
    Rich Hawryluk (Photo by Elle Starkman )

    Rich Hawryluk has been appointed interim director of the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) while an international search for a permanent director moves forward, Princeton University Vice President for PPPL David McComas announced recently. Hawryluk, who has been heading the NSTX-U Recovery Project, is an internationally-known physicist and a former deputy director of PPPL.

    PPPL NSTX-U

    “Rich has earned my highest respect and the respect of his colleagues and staff at PPPL and of researchers throughout the world for his work as a scientist, project manager, and leader. I am delighted he has agreed to head the Laboratory as we move into the next phase of the NSTX-U recovery,” McComas said.

    Hawryluk said that he was grateful for the opportunity to lead the Laboratory where he has worked for more than four decades. “I feel deeply about this place,” he said. “It has given me enormous opportunities to do research, as well as scientific and technical management. I feel it’s incumbent on me to do all I possibly can to give the scientists and the engineers and the staff here exciting and productive scientific opportunities both in the near future as well for the long term.”

    Terry Brog, who served as interim director since September 2016, will return to his previous position as deputy director for operations and chief operating officer that he assumed in June of 2016. Stacia Zelick, who served as interim deputy director for operations under Brog, will continue to serve in a leadership role. Michael Zarnstorff, the deputy director for research, will remain in his position. Physicists Jon Menard, head of NSTX-U research and Stefan Gerhardt, deputy engineering director for the project, will now lead the NSTX-U Recovery Project. Charles Neumeyer will remain as the NSTX-U Recovery Project engineering director and deputy head of engineering for NSTX-U.

    The leadership change comes as PPPL moves ahead with constructing prototype magnets in preparation for replacing the one that failed last year and five others that were built under similar conditions.

    Construction of the first prototype magnet follows a comprehensive review of each system of NSTX-U by a team of engineers and scientists from PPPL as well as nearly 50 external experts from the United States and around the world.

    “For the Laboratory to succeed, we must utilize the talents, creativity and skills of all of the staff,” Hawryluk said. “My job is to enable other people to address the issues facing the Laboratory and to set a firm foundation for the future director.”

    Hawryluk and McComas both thanked Brog and Zelick for their leadership during the past several months. “I’m extremely grateful for all the work that Terry and Stacia have done in their respective roles over the last year,” McComas said. Hawryluk also noted that it was his pleasure to work with the NSTX-U team and, in particular, Charlie Neumeyer, Stefan Gerhardt and Jon Menard who “are very dedicated to bringing NSTX-U back on line.”

    The new interim director has been at PPPL for most of his career. He came to PPPL in 1974 after receiving a Ph.D. in physics from MIT. He headed the Tokamak Fusion Test Reactor, then the largest magnetic confinement fusion facility in the United States, from 1991 to 1997. Hawryluk oversaw all research and technical operations as deputy director of the Laboratory for 11 years from 1997 to 2008. He was then head of PPPL’s ITER and Tokamaks Department from 2009 to 2011. From 2011 to 2013, Hawryluk worked at ITER in France, serving as the deputy director-general for the Administration Department of ITER.

    ITER Tokamak in Saint-Paul-lès-Durance, which is in southern France

    In 2013, Hawryluk returned to the Laboratory as head of the ITER and Tokamaks department. He remained in that position until he became head of the Recovery Project last year. Hawryluk has received numerous awards during his career including a Department of Energy Distinguished Associate Award, a Kaul Foundation Prize for Excellence in Plasma Physics Research and Technology, a Fusion Power Award, and an American Physical Society Prize for Excellence in Plasma Physicswith physicists Rob Goldston and James Strachan. A fellow of the American Association for the Advancement of Science since 2008 and of the American Physical Society since 1986, he also chairs the board of editors of Nuclear Fusion, a monthly journal devoted to controlled fusion energy.

    Hawryluk and his wife Mary Katherine Hawryluk, a school psychologist working with special needs children at the New Road School in Parlin, New Jersey, met as undergraduates and have been married for 41 years. They have two grown sons: Kevin, who lives in Chicago, and David, who lives in Los Angeles. In his spare time, Hawryluk is an avid reader.

    “I’m taking on this task because I really believe in PPPL and its critical role in furthering the field of plasma physics with the goal of developing fusion energy,” Hawryluk said. “I am committed to addressing issues that are central to the long-term success of the Laboratory.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition


    PPPL campus

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

     
  • richardmitnick 4:50 pm on May 27, 2017 Permalink | Reply
    Tags: China EAST, , ITER, KIT Wendelstein 7-X, , Tokamak energy a Brisish endeavor,   

    From Universe Today: “How Far Away is Fusion? Unlocking the Power of the Sun’ 

    universe-today

    Universe Today

    27 May , 2017
    Fraser Cain


    I’d like to think we’re smarter than the Sun.

    Let’s compare and contrast. Humans, on the one hand, have made enormous advances in science and technology, built cities, cars, computers, and phones. We have split the atom for war and for energy.

    What has the Sun done? It’s a massive ball of plasma, made up of mostly hydrogen and helium. It just, kind of, sits there. Every now and then it burps up hydrogen gas into a coronal mass ejection. It’s not a stretch to say that the Sun, and all inanimate material in the Universe, isn’t the sharpest knife in the drawer.

    And yet, the Sun has mastered a form of energy that we just can’t seem to wrap our minds around: fusion. It’s really infuriating, seeing the Sun, just sitting there, effortlessly doing something our finest minds have struggled with for half a century.

    Why can’t we make fusion work? How long until we can finally catch up technologically with a sphere of ionized gas?

    The trick to the Sun’s ability to generate power through nuclear fusion, of course, comes from its enormous mass. The Sun contains 1.989 x 10^30 kilograms of mostly hydrogen and helium, and this mass pushes inward, creating a core heated to 15 million degrees C, with 150 times the density of water.

    It’s at this core that the Sun does its work, mashing atoms of hydrogen into helium. This process of fusion is an exothermic reaction, which means that every time a new atom of helium is created, photons in the form of gamma radiation are also released.

    The only thing the Sun uses this energy for is light pressure, to counteract the gravity pulling everything inward. Its photons slowly make their way up through the Sun and then they’re released into space. So wasteful.

    How can we replicate this on Earth?

    1
    Inside a Tokamak. Image credit: Lawrence Berkeley Labs

    The main technology developed to do this is called a tokamak reactor; it’s a based on a Russian acronym for: “toroidal chamber with magnetic coils”, and the first prototypes were created in the 1960s. There are many different reactors in development, but the method is essentially the same.

    A vacuum chamber is filled with hydrogen fuel. Then an enormous amount of electricity is run through the chamber, heating up the hydrogen into a plasma state. They might also use lasers and other methods to get the plasma up to 150 to 300 million degrees Celsius (10 to 20 times hotter than the Sun’s core).

    Superconducting magnets surround the fusion chamber, containing the plasma and keeping it away from the chamber walls, which would melt otherwise.

    Once the temperatures and pressures are high enough, atoms of hydrogen are crushed together into helium just like in the Sun. This releases photons which heat up the plasma, keeping the reaction going without any addition energy input.

    Excess heat reaches the chamber walls, and can be extracted to do work.

    2
    The spherical tokamak MAST at the Culham Centre for Fusion Energy (UK). Photo: CCFE

    The challenge has always been that heating up the chamber and constraining the plasma uses up more energy than gets produced in the reactor. We can make fusion work, we just haven’t been able to extract surplus energy from the system… yet.

    Compared to other forms of energy production, fusion should be clean and safe. The fuel source is water, and the byproduct is helium (which the world is actually starting to run out of). If there’s a problem with the reactor, it would cool down and the fusion reaction would stop.

    The high energy photons released in the fusion reaction will be a problem, however. They’ll stream into the surrounding fusion reactor and make the whole thing radioactive. The fusion chamber will be deadly for about 50 years, but its rapid half-life will make it as radioactive as coal ash after 500 years.

    PPPL NSTX -U at Princeton Plasma Physics Lab, Princeton, NJ,USA

    Fusion experiments are measured by the amount of energy they produce compared to the amount of energy you put into them. For example, if a fusion plant required 100MW of electrical energy to produce 10 MW of output, it would have an energy ratio of 0.1. You want at least a ratio of 1. That means energy in equals energy out, and so far, no experiment has ever reached that ratio. But we’re close.

    3
    The Chinese EAST facility’s tokamak reactor, part of the Institute of Physical Science in Hefei. Credit: ipp.cas.cn

    Wendelstgein 7-X stellarator, built in Greifswald, Germany

    ITER Tokamak ITER Tokamak in Saint-Paul-lès-Durance, which is in southern France

    ITER is enormous, measuring 30 meters across and high. And its fusion chamber is so large that it should be able to create a self-sustaining fusion reaction. The energy released by the fusing hydrogen keeps the fuel hot enough to keep reacting. There will still be energy required to run the electric magnets that contain the plasma, but not to keep the plasma hot.

    And if all goes well, ITER will have a ratio of 10. In other words, for every 10 MW of energy pumped in, it’ll generate 100 MW of usable power.

    ITER is still under construction, and as of June 2015, the total construction costs had reached $14 billion. The facility is expected to be complete by 2021, and the first fusion tests will begin in 2025.

    So, if ITER works as planned, we are now about 8 years away from positive energy output from fusion. Of course, ITER will just be an experiment, not an actual powerplant, so if it even works, an actual fusion-based energy grid will be decades after that.

    At this point, I’d say we’re about a decade away from someone demonstrating that a self-sustaining fusion reaction that generates more power than it consumes is feasible. And then probably another 2 decades away from them supplying electricity to the power grid. By that point, our smug Sun will need to find a new job.

    [The old saying, thirty years old, is that fusion is 30 years away. PPPL is down for two years down to error and malfuntion. LLNL/NIF has gieven up is laser trials and is not even mentioned her. Iter is so far behind and so over budget it faces constant fears of financial support disappearing. Tokamak Energy, a British attempt, is having some success. it should have been included in this article.]

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 7:19 am on March 28, 2017 Permalink | Reply
    Tags: , , , ITER, ,   

    From NYT: “A Dream of Clean Energy at a Very High Price”, a Now Too Old Subject 

    New York Times

    The New York Times

    MARCH 27, 2017
    HENRY FOUNTAIN

    1
    Source: ITER Organization Mika Gröndahl/The New York Times

    SAINT-PAUL-LEZ-DURANCE, France — At a dusty construction site here amid the limestone ridges of Provence, workers scurry around immense slabs of concrete arranged in a ring like a modern-day Stonehenge.

    It looks like the beginnings of a large commercial power plant, but it is not. The project, called ITER, is an enormous, and enormously complex and costly, physics experiment. But if it succeeds, it could determine the power plants of the future and make an invaluable contribution to reducing planet-warming emissions.

    ITER, short for International Thermonuclear Experimental Reactor (and pronounced EAT-er), is being built to test a long-held dream: that nuclear fusion, the atomic reaction that takes place in the sun and in hydrogen bombs, can be controlled to generate power.

    First discussed in 1985 at a United States-Soviet Union summit, the multinational effort, in which the European Union has a 45 percent stake and the United States, Russia, China and three other partners 9 percent each, has long been cited as a crucial step toward a future of near-limitless electric power.

    ITER will produce heat, not electricity. But if it works — if it produces more energy than it consumes, which smaller fusion experiments so far have not been able to do — it could lead to plants that generate electricity without the climate-affecting carbon emissions of fossil-fuel plants or most of the hazards of existing nuclear reactors that split atoms rather than join them.

    Success, however, has always seemed just a few decades away for ITER. The project has progressed in fits and starts for years, plagued by design and management problems that have led to long delays and ballooning costs.

    ITER is moving ahead now, with a director-general, Bernard Bigot, who took over two years ago after an independent analysis that was highly critical of the project. Dr. Bigot, who previously ran France’s atomic energy agency, has earned high marks for resolving management problems and developing a realistic schedule based more on physics and engineering and less on politics.

    “I do believe we are moving at full speed and maybe accelerating,” Dr. Bigot said in an interview.

    The site here is now studded with tower cranes as crews work on the concrete structures that will support and surround the heart of the experiment, a doughnut-shaped chamber called a tokamak. This is where the fusion reactions will take place, within a plasma, a roiling cloud of ionized atoms so hot that it can be contained only by extremely strong magnetic fields.

    2
    By The New York Times

    Pieces of the tokamak and other components, including giant superconducting electromagnets and a structure that at approximately 100 feet in diameter and 100 feet tall will be the largest stainless-steel vacuum vessel ever made, are being fabricated in the participating countries. Assembly is set to begin next year in a giant hall erected next to the tokamak site.

    3
    At the ITER construction site, immense slabs of concrete lie in a ring like a modern-day Stonehenge. Credit ITER Organization

    There are major technical hurdles in a project where the manufacturing and construction are on the scale of shipbuilding but the parts need to fit with the precision of a fine watch.

    “It’s a challenge,” said Dr. Bigot, who devotes much of his time to issues related to integrating parts from various countries. “We need to be very sensitive about quality.”

    Even if the project proceeds smoothly, the goal of “first plasma,” using pure hydrogen that does not undergo fusion, would not be reached for another eight years. A so-called burning plasma, which contains a fraction of an ounce of fusible fuel in the form of two hydrogen isotopes, deuterium and tritium, and can be sustained for perhaps six or seven minutes and release large amounts of energy, would not be achieved until 2035 at the earliest.

    That is a half century after the subject of cooperating on a fusion project came up at a meeting in Geneva between President Ronald Reagan and the Soviet leader Mikhail S. Gorbachev. A functional commercial fusion power plant would be even further down the road.

    “Fusion is very hard,” said Riccardo Betti, a researcher at the University of Rochester who has followed the ITER project for years. “Plasma is not your friend. It tries to do everything it can to really displease you.”

    Fusion is also very expensive. ITER estimates the cost of design and construction at about 20 billion euros (currently about $22 billion). But the actual cost of components may be higher in some of the participating countries, like the United States, because of high labor costs. The eventual total United States contribution, which includes an enormous central electromagnet capable, it is said, of lifting an aircraft carrier, has been estimated at about $4 billion.

    Despite the recent progress there are still plenty of doubts about ITER, especially in the United States, which left the project for five years at the turn of the century and where funding through the Energy Department has long been a political football.

    The department confirmed its support for ITER in a report last year and Congress approved $115 million for it. It is unclear, though, how the project will fare in the Trump administration, which has proposed a cut of roughly 20 percent to the department’s Office of Science, which funds basic research including ITER. (The department also funds another long-troubled fusion project, which uses lasers, at Lawrence Livermore National Laboratory in California.)

    Dr. Bigot met with the new energy secretary, Rick Perry, last week in Washington, and said he found Mr. Perry “very open to listening” about ITER and its long-term goals. “But he has to make some short-term choices” with his budget, Dr. Bigot said.

    Energy Department press aides did not respond to requests for comment.

    Some in Congress, including Senator Lamar Alexander, Republican of Tennessee, while lauding Dr. Bigot’s efforts, argue that the project already consumes too much of the Energy Department’s basic research budget of about $5 billion.

    “I remain concerned that continuing to support the ITER project would come at the expense of other Office of Science priorities that the Department of Energy has said are more important — and that I consider more important,” Mr. Alexander said in a statement.

    While it is not clear what would happen to the project if the United States withdrew, Dr. Bigot argues that it is in every participating country’s interest to see it through. “You have a chance to know if fusion works or not,” he said. “If you miss this chance, maybe it will never come again.”

    But even scientists who support ITER are concerned about the impact it has on other research.

    “People around the country who work on projects that are the scientific basis for fusion are worried that they’re in a no-win situation,” said William Dorland, a physicist at the University of Maryland who is chairman of the plasma science committee of the National Academy of Sciences. “If ITER goes forward, it might eat up all the money. If it doesn’t expand and the U.S. pulls out, it may pull down a lot of good science in the downdraft.”

    In the ITER tokamak, deuterium and tritium nuclei will fuse to form helium, losing a small amount of mass that is converted into a huge amount of energy. Most of the energy will be carried away by neutrons, which will escape the plasma and strike the walls of the tokamak, producing heat.

    In a fusion power plant, that heat would be used to make steam to turn a turbine to generate electricity, much as existing power plants do using other sources of heat, like burning coal. ITER’s heat will be dissipated through cooling towers.

    There is no risk of a runaway reaction and meltdown as with nuclear fission and, while radioactive waste is produced, it is not nearly as long-lived as the spent fuel rods and irradiated components of a fission reactor.

    To fuse, atomic nuclei must move very fast — they must be extremely hot — to overcome natural repulsive forces and collide. In the sun, the extreme gravitational field does much of the work. Nuclei need to be at a temperature of about 15 million degrees Celsius.

    In a tokamak, without such a strong gravitational pull, the atoms need to be about 10 times hotter. So enormous amounts of energy are required to heat the plasma, using pulsating magnetic fields and other sources like microwaves. Just a few feet away, on the other hand, the windings of the superconducting electromagnets need to be cooled to a few degrees above absolute zero. Needless to say, the material and technical challenges are extreme.

    Although all fusion reactors to date have produced less energy than they use, physicists are expecting that ITER will benefit from its larger size, and will produce about 10 times more power than it consumes. But they will face many challenges, chief among them developing the ability to prevent instabilities in the edges of the plasma that can damage the experiment.

    Even in its early stages of construction, the project seems overwhelmingly complex. Embedded in the concrete surfaces are thousands of steel plates. They seem to be scattered at random throughout the structure, but actually are precisely located. ITER is being built to French nuclear plant standards, which prohibit drilling into concrete. So the plates — eventually about 80,000 of them — are where other components of the structure will be attached as construction progresses.

    A mistake or two now could wreak havoc a few years down the road, but Dr. Bigot said that in this and other work on ITER, the key to avoiding errors was taking time.

    “People consider that it’s long,” he said, referring to critics of the project timetable. “But if you want full control of quality, you need time.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 10:09 am on December 12, 2016 Permalink | Reply
    Tags: , , , ITER, ,   

    From PPPL: “PPPL physicists win funding to lead a DOE exascale computing project” 


    PPPL

    October 27, 2016 [Just now out on social media.]
    Raphael Rosen

    1
    PPPL physicist Amitava Bhattacharjee. (Photo by Elle Starkman/PPPL Office of Communications)

    A proposal from scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) has been chosen as part of a national initiative to develop the next generation of supercomputers. Known as the Exascale Computing Project (ECP), the initiative will include a focus on exascale-related software, applications, and workforce training.

    Once developed, exascale computers will perform a billion billion operations per second, a rate 50 to 100 times faster than the most powerful U.S. computers now in use. The fastest computers today operate at the petascale and can perform a million billion operations per second. Exascale machines in the United States are expected to be ready in 2023.

    The PPPL-led multi-institutional project, titled High-Fidelity Whole Device Modeling of Magnetically Confined Fusion Plasmas, was selected during the ECP’s first round of application development funding, which distributed $39.8 million. The overall project will receive $2.5 million a year for four years to be distributed among all the partner institutions, including Argonne, Lawrence Livermore, and Oak Ridge national laboratories, together with Rutgers University, the University of California, Los Angeles, and the University of Colorado, Boulder. PPPL itself will receive $800,000 per year; the project it leads was one of 15 selected for full funding, and the only one dedicated to fusion energy. Seven additional projects received seed funding.

    The application efforts will help guide DOE’s development of a U.S. exascale ecosystem as part of President Obama’s National Strategic Computing Initiative (NSCI). DOE, the Department of Defense and the National Science Foundation have been designated as NSCI lead agencies, and ECP is the primary DOE contribution to the initiative.

    The ECP’s multi-year mission is to maximize the benefits of high performance computing (HPC) for U.S. economic competitiveness, national security and scientific discovery. In addition to applications, the DOE project addresses hardware, software, platforms and workforce development needs critical to the effective development and deployment of future exascale systems. The ECP is supported jointly by DOE’s Office of Science and the National Nuclear Security Administration within DOE.

    PPPL has been involved with high-performance computing for years. PPPL scientists created the XGC code, which models the behavior of plasma in the boundary region where the plasma’s ions and electrons interact with each other and with neutral particles produced by the tokamak’s inner wall. The high-performance code is maintained and updated by PPPL scientist C.S. Chang and his team.

    3
    PPPL scientist C.S. Chang

    XGC runs on Titan, the fastest computer in the United States, at the Oak Ridge Leadership Computing Facility, a DOE Office of Science User Facility at Oak Ridge National Laboratory.

    ORNL Cray Titan Supercomputer
    ORNL Cray Titan Supercomputer

    The calculations needed to model the behavior of the plasma edge are so complex that the code uses 90 percent of the computer’s processing capabilities. Titan performs at the petascale, completing a million billion calculations each second, and the DOE was primarily interested in proposals by institutions that possess petascale-ready codes that can be upgraded for exascale computers.

    The PPPL proposal lays out a four-year plan to combine XGC with GENE, a computer code that simulates the behavior of the plasma core. GENE is maintained by Frank Jenko, a professor at the University of California, Los Angeles. Combining the codes would give physicists a far better sense of how the core plasma interacts with the edge plasma at a fundamental kinetic level, giving a comprehensive view of the entire plasma volume.

    Leading the overall PPPL proposal is Amitava Bhattacharjee, head of the Theory Department at PPPL. Co-principal investigators are PPPL’s Chang and Andrew Siegel, a computational scientist at the University of Chicago.

    The multi-institutional effort will develop a full-scale computer simulation of fusion plasma. Unlike current simulations, which model only part of the hot, charged gas, the proposed simulations will display the physics of an entire plasma all at once. The completed model will integrate the XGC and GENE codes and will be designed to run on exascale computers.

    The modeling will enable physicists to understand plasmas more fully, allowing them to predict its behavior within doughnut-shaped fusion facilities known as tokamaks. The exascale computing fusion proposal focuses primarily on ITER, the international tokamak being built in France to demonstrate the feasibility of fusion power.

    Iter experimental tokamak nuclear fusion reactor that is being built next to the Cadarache facility in Saint Paul les-Durance south of France
    Iter experimental tokamak nuclear fusion reactor that is being built next to the Cadarache facility in Saint Paul les-Durance south of France

    But the proposal will be developed with other applications in mind, including stellarators, another variety of fusion facility.

    Wendelstgein 7-X stellarator
    Wendelstgein 7-X stellarator,built in Greifswald, Germany

    Better predictions can lead to better engineered facilities and more efficient fusion reactors. Currently, support for this work comes from the DOE’s Advanced Science Computing Research program.

    “This will be a team effort involving multiple institutions,” said Bhattacharjee. He noted that PPPL will be involved in every aspect of the project, including working with applied mathematicians and computer scientists on the team to develop the simulation framework that will couple GENE with XGC on exascale computers.

    “You need a very-large-scale computer to calculate the multiscale interactions in fusion plasmas,” said Chang. “Whole-device modeling is about simulating the whole thing: all the systems together.”

    Because plasma behavior is immensely complicated, developing an exascale computer is crucial for future research. “Taking into account all the physics in a fusion plasma requires enormous computational resources,” said Bhattacharjee. “With the computer codes we have now, we are already pushing on the edge of the petascale. The exascale is very much needed in order for us to have greater realism and truly predictive capability.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

     
  • richardmitnick 11:20 am on May 2, 2016 Permalink | Reply
    Tags: , , , ITER,   

    From COSMOS: “Getting primed for fusion power” 

    Cosmos Magazine bloc

    COSMOS

    26 Apr 2016
    Cathal O’Connell

    Cracking fusion power would be one of the great technological achievements of the 21st century, providing almost limitless power with few drawbacks. With global efforts getting bigger and badder every year, Cathal O’Connell provides a primer to the basic technology.

    ITER Tokamak
    ITER Tokamak

    Fusion power is such a huge, potentially game-changing technology that it’s easy to get swept up in its utopian promise. Equally, it’s easy to dismiss the whole shebang as a wild fantasy that will never come to pass.

    Here’s what you need to know to help keep pace with developments in this global quest.

    What is nuclear fusion?

    Atoms are the really small bits from which we are all made. Inside each atom, when you strip away the shells of electrons, is an even smaller bit at the core – the nucleus.

    It turns out that when you join two small nuclei to make a bigger one, an enormous amount of energy is released – about 10 million times more energy than the puny chemical reactions that power most of our technology, such as burning oil, coal or the gasoline in your car.

    We know fusion works because it goes on in the core of the Sun. All the Sun’s heat and light are powered by fusion. The most important reaction is the fusion of two nuclei of hydrogen, which is the lightest atom, combine to form helium, the second lightest.

    How does it work?

    Igniting nuclear fusion is not as simple as starting a fire. It takes a lot of energy to get it going and typically, that means a temperature of millions of degrees Celsius.

    This is because atomic nuclei have a love-hate relationship. Each nucleus has a strong positive charge so they repel one another. To kickstart fusion, you have to overcome this repulsive barrier by ramming two nuclei together incredibly hard. That’s what happens in the core of the Sun, where the temperature is about 15 million °C and pressures are similarly insane.

    When the nuclei get close enough to touch, the nuclear strong force takes over – the strongest force in nature – and it’s the source of fusion energy.

    Fusion energy?

    The idea of fusion energy is to build power plants that generate energy by recreating the core of the Sun. Hundreds of research scale reactors have been built around the world.

    They are usually engineering marvels designed to containment hydrogen nuclei at a 100 million °C, or implode a nuclear pellet using massive lasers (see below).
    But I thought we already had nuclear power

    The nuclear power plants we have so far are based on a different process – nuclear fission, where you derive energy by splitting one big atom into two smaller atoms. That’s a much easier process and so fission reactors have been pumping power into the grid since the 1950s.

    Fusion reactors are much safer than traditional fission reactors because there is no chance of a runaway explosion and when the reaction is done, there’s no long-lived radioactive waste.

    Per kilogram of fuel, fusion releases four times more energy than fission and 10 million times more than coal.

    What’s the fuel?

    The first generations of fusion reactors will likely use two forms of hydrogen for the fuel – deuterium and tritium – because the fusion of these two nuclei is the easiest to achieve.

    Regular hydrogen is the smallest atom – just one electron orbiting a proton nucleus. Deuterium is a fatter version of hydrogen, where the nucleus contains a neutron as well as a proton. And tritium is the fattest hydrogen of all – its nucleus contains a proton and two neutrons.

    Deuterium is easily found in seawater, while tritium can be generated from lithium.

    The long-term goal is to switch to a deuterium-deuterium reaction, meaning all the world’s energy supply could one day be found in seawater.

    Has fusion ever been achieved?

    Humans first managed nuclear fusion on 1 November 1952 when the US exploded the first fusion bomb. Fusion bombs (also known as hydrogen bombs) are the most destructive weapons ever made. They typically use a fission-based atomic bomb to trigger a fusion reaction in the second stage.

    The challenge now is achieving fusion in a controlled manner.

    For more than 70 years researchers have been trialling different designs for containing the fusion reaction. Some of these designs (see below) have achieved fusion. The problem is releasing more energy than is put in, and doing it long enough to be useful. Nobody’s been able to do that yet.
    What’s been holding us back?

    Ah. The problem is the temperature. You have to heat the fuel to such a high temperature (100 million °C or so) that no material vessel could possibly contain it.

    The basic physics behind fusion has been known for decades. It’s the engineering that still needs to be worked out.

    What do fusion reactors look like?

    Fusion reactors come in all sorts of shapes and sizes.

    Most research has looked at containing the reaction within a sort of magnetic bottle. At the extreme temperatures of fusion, all of the electrons are stripped off the deuterium and tritium atoms, and what’s left is called a plasma.

    1
    How a tokamak, or toroidal magnetic confinement system, works.Credit: Encyclopaedia Britannica/UIG Via Getty Images

    The most common design is the toroidal chamber-magnetic (tokamak), which looks a bit like the inside of the Deathstar. Tokamaks form twisting donut-shapes called a torus. The plasma runs in rings and never touches the walls of the torus because it’s contained by the magnetic fields.

    Other variations confined the plasma in different geometries, such as the stellerator design which adds a twist with a different configuration of magnets. Other tokamak designs are spherical.
    But if fuel is squeezed in a magnetic field, how do you get the energy out?

    When deuterium fuses with tritium, an extra neutron is kicked out and receives a huge kick of energy. The neutron is a neutral particle, and so is not affected by the magnetic field – it can fly through the magnetic bottle and smash into a lithium blanket just inside the donut.

    The neutron collisions heat up the lithium. This heat is used to convert water into steam which drives turbines to generate electricity, just like in any other electric power-plant.
    What’s this about using lasers?

    Instead of using a magnetic field to contain a plasma, another idea is to ignite small fusion explosions by firing a powerful laser at a pellet.

    LLNL NIF
    LLNL/NIF

    At the National Ignition Facility at Lawrence Livermore National Laboratory in California, the world’s biggest laser (made of 192 laser beams) are fired simultaneously at a pellet of deuterium/tritium about the size of a pea.

    National Ignition Facility researchers have achieved fusion using this design, but the challenge is extracting more energy than is used to power the lasers. Their biggest problem is in constructing the pellet and its plastic container in the shape to absorb all the laser energy.

    And cold fusion?

    This is the idea to make a fusion reactor that works at close to room temperature. In 1989, British and American scientists seemed to achieve this a running a strong current through a platinum electrode in a thermos of heavy water (water where the hydrogen atoms are partially or completely replaced by deuterium) – but the experiment turned out to be flawed.

    Nowadays research into cold fusion is seen as an example of “pathological science”, like trying to build a perpetual motion machine.

    Best forget about this altogether. It’s not going to happen.

    What’s next for fusion?

    Despite the difficulties, progress in fusion power has actually been very rapid. Power output has increased by a factor of more than a million in 30 years.

    Much of the hope is centred on the ITER (Latin for “the way”) tokamak to be constructed in southern France by 2019.

    3
    ITER, the International Thermonuclear Experimental Reactor, is being designed to test the principles surrounding the generation of power from nuclear fusion, the energy source of stars. It comprises a toroidal chamber in which a plasma (pink) is contained by strong magnetic fields.Credit: MIKKEL JUUL JENSEN / SCIENCE PHOTO LIBRARY/Getty Images

    This design has been in the pipeline for two decades and is designed to be the first fusion reactor to produce more energy (about 10 times more) than it puts in. However, this 500-megawatt reactor is still only a proof-of-concept design, and no electricity will be generated.

    If ITER is successful, the next step is DEMO – which is designed to be the world’s first nuclear power plant to generate electricity, to be constructed by 2033.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: