To celebrate the 75th anniversary of the birth of its nuclear reactors just past December 2017, MIT restarted the historic graphite index heap, which became a new tool for education and research.
At this special moment, we interviewed Professor Hu Lingwen, head of MIT nuclear laboratory and nuclear reactor expert, and she also shared with us the challenges and new opportunities currently facing nuclear energy around the world.
Senior researcher Hu Lingwen loaded the fuel rods into the fuel channels of the MIT graphite index stack
Q: Since the hottest industry is AI today, many people have turned their backs to ComputerScience. Nuclear energy is a relatively unpopular industry. Why did you choose nuclear energy? Especially as a female. In the field of nuclear energy, is there an AI or What is the role of the hottest technology in this era in nuclear energy?
Hu Lingwen: Probably, in the 1980s, when I was still in high school, I started to have an interest in the field of nuclear energy. "Nuclear fission can generate millions of times the energy of coal chemical combustion," a concept that was deeply enticing at the time And at that moment, there were very few women entering the science and engineering industry, so I am very grateful for my chance to study nuclear engineering at Tsinghua University in Taiwan before I studied at the Massachusetts Institute of Technology (MIT) in 1996 Engineering and Ph.D.
Since the 1960s, nuclear energy has been regarded as one of the reliable and environmentally friendly sources of power generation, and most of the currently operating commercial nuclear power plants are light water reactor nuclear power stations designed in the 1960s and 1970s. For further improving the safety of nuclear power Sexuality and economy, broaden the space for future development of nuclear power, and tackle the current severe global climate change issues, it is of crucial importance to develop, display and promote more advanced nuclear reactor technologies.
At present, many technological innovations can be used in the design of first-generation reactors, such as advanced manufacturing processes, high-precision sensing and a variety of devices, as well as more optimized methods of computation and modeling, and in my opinion, artificial intelligence AI) technology has the potential to significantly reduce the operating costs of nuclear power and improve the safety of nuclear power.
Q: What technical challenges do you have in presenting the advantages of 'subcritical reactors' compared with traditional nuclear reactors?
Hu Lingwen: The time required to build a model reactor is too long, and this issue is one of the major challenges currently facing the development of new nuclear reactors (starting with the treatment of site selection and licensing instruments, which is currently at least a decade or so), so to speed up MIT My team came up with the concept of a subcritical reactor that uses the MIT reactor as a source of neutrons for driving subcritical molten salt reactors and does not require new venues and new reactor permits Instruments, thus drastically reducing the time and cost of building a model new reactor.
Although, as a subcritical reactor will only simulate part of the reactor core, and regulatory authorities may eventually need to build a complete prototype demonstration reactor, subcritical reactors should be able to provide advice on the design of new reactors Early, critical data for sex enables developers to more easily access funding and approval instruments for building prototypes.
Q: Where is the future of nuclear energy development? Are advanced fission reactors, such as molten salt reactors and fast reactors, or miniaturized reactor with inherent safety or fusion reactor? Which of the six advanced reactor types do you think may be The first to come to the fore?
Hu Lingwen: In the future, which nuclear power technology we will use depends on the specific regional and actual needs. Small modular reactors have the characteristics of high safety and low capital investment. Molten salt reactors and other high temperature reactors provide a new fuel cycle solution , Which is far more economical than existing light-water reactors, which convert nuclear waste into fuel and thus make efficient use of uranium resources as a long-term source of energy, but all of these new reactors Design will require further research and development in order to be really put into construction and use.
Massachusetts Institute of Technology nuclear reactor laboratory door
Q: What are the challenges currently facing nuclear energy development and what exciting breakthroughs are there?
Hu Lingwen: In my opinion, one of the main challenges facing nuclear energy technology development now is how to maintain reliable and steady funding for research and development as well as international cooperation. It is exciting that the United States now starts to have private funds to invest in nuclear technology development. The government Also introduced some supportive initiatives.In addition, international cooperation can accelerate the next generation of nuclear power technology development process.For example, TerryPower of Bill Gates and China National Nuclear Corporation reached an agreement on the development of traveling wave reactors.And MIT is currently Molting salt reactors are being developed in cooperation with the Chinese Academy of Sciences, and I believe they will eventually be resolved only through international cooperation, such as the global challenges of climate change and pollution.
The above is the full text of the interview conducted by Prof. DT Jun and Prof. Hu Lingwen, and I believe readers are still very curious about Professor Hu Lingwen and MIT nuclear laboratory led by her. The future trend of global energy revolution is also a topic of concern to many people. Professor Hu Lingwen has accepted the invitation of DT Jun and will attend the upcoming EmTech Emerging Technologies Summit in Beijing at the end of this month. This will bring us more exciting cutting-edge technology perspectives, so stay tuned!
MIT restart graphite pile full review
December 2, 1942 Under the stand of the Stagg Field football stadium at the University of Chicago, Nobel Prize winner Enrico Fermi led the experimental team for the first time in a controlled-chain nuclear reaction - The beginning also laid the foundation for the development of the first atomic bomb and the first nuclear power reactor.
Seventy-five years later, to commemorate the first critical mass of the Chicago Heap (CP-1), MIT restarted as ground-breaking as the Chicago event on Saturday. MIT's subcritical facilities and CP-1 reactor development and self- Nuclear reaction as landmark.
Nuclear Science and Engineering and Nuclear Reactor Laboratories Celebrate the 75th Anniversary of CP-1's Human First Chain Nuclear Reaction
The same reactor grade graphite as the MIT graphite index stack was made into a souvenir
The memorial was not just a mere walk in. The researchers restarted a plant called the Graphite Index heap, which was first built in 1957 and will be used by MIT students for subcritical experiments in the coming years. In the future, It will also become a unique and valuable research tool.
The device is a large cube-shaped reactor made of pure graphite (pencil lead material) with holes for uranium insertion. The natural uranium rod has a very low radiation dose and is safe for direct bare hands. This is what Fermi and his colleagues did, though they also had protective gloves.
In the decades since Fermi's reactor experiments, more than 20 similar graphite heaps have been built by U.S. universities and national laboratories for basic research and teaching, but most of them have been disposed of over time. The pile was only half as large as the Fermi reactor, but it was the largest of the post-build graphite heaps and remained, but it has been forgotten and left unused for many years until last year by Michael Schott, MIT's nuclear science and engineering department Short Professor "rediscover".
On December 2, Professor Smith introduced the history of the graphite index heap to 45 guests at MIT's Nuclear Reactor Laboratory.
Kord Smith, a professor of nuclear science and engineering, was surprised to learn that the device was still intact, with metal panel protection on its surface that looked like an abandoned storage cabinet and passed by teachers and students Not aware of its existence.Smith and his colleagues in the Department of Nuclear Science and Engineering, as well as director of the nuclear reactor laboratory David Moncton quickly developed a restart plan to commemorate the reactor pioneering experiments 75 Anniversary In 1957, MIT nuclear science and engineering student Richard Knapp designed the reactor system in his bachelor's thesis.
At present, 30 tons of graphite and 2.5 tons of uranium have been completely cleaned and recovered, and the last piece of uranium was also ceremonially loaded on December 2. This ceremony invited 45 teachers, students and guests to witness the time It was exactly the time that the Chicago reactors were completed, when the number was 45.
According to Smith, MIT's sub-critical graphite reactor was eventually phased out as the nuclear industry quickly shifted from graphite to light, heavy water and sodium-cooled reactors, and experiments on graphite systems were not associated with the nuclear industry. Graphite (or water) acts as a moderator, reducing the speed of the neutrons emitted by the radiation source to the original one million. Then, the thermal neutrons interact with other uranium atoms to form a self-sustaining chain reaction, ie neutrons The new neutron forms a series of collisions by releasing more neutrons by striking the uranium atom.The critical point of the CP-1 is controlled by the plugging of a control rod made of cadmium that absorbs neutrons and interrupts the reaction.
Colder Smith and McGarle Giles standing in front of the graphite index pile will serve as teaching and research tools for students
Today's next-generation nuclear reactors, which have many cutting-edge designs, including passive cooling systems and non-stop fuel-for-fuel designs, have started to reuse graphite again, making the reactor once again a useful research tool that allows students to deal with nuclear fuel, But also easier access to the reactor MIT Although it has a full-power research reactor, but it is operating almost year round and produce 6MW thermal energy.Research on the reactor can be a new type of fuel rod cladding or monitoring instruments, but a Year experiment only once.
According to Smith, students will be able to install, run experiments and get results within a few hours or days on a graphite index stack. The use of the graphite stack is expected to spark student interest and to be at the forefront of MIT research reactors Prepare sex experiment.
"In the past years, graphite has been used as a reactor medium for many times," said Smith, but now we are reborn. "Even today, how neutrons released by nuclear reactions scatter through the crystal structure of graphite, Still has important research value.Smith said that recently a new physical model has been proposed to describe these interactions and we hope to use graphite heap to design experiments to validate these new theoretical models.
Smith believes that in addition to helping to study new types of reactors, fuels and cladding, graphite reactors and MIT research reactors will also be valuable educational tools for nuclear engineering students. "We tend to be good at developing Students who calculate algorithms and models, but you can think your simulation is perfect if you can not compare your calculations. "However, in the real world, the actual measurements do not usually fit the expectations perfectly, knowing that these differences help To enhance the theoretical model.