A fast reactor system to shorten the lifetime of long-lived fission productsNovember 14, 2017
A team of scientists at Tokyo Institute of Technology (Tokyo Tech) working in collaboration with Tohoku University, Tokyo City University and the Japan Atomic Energy Agency has proposed a novel approach to tackle the problem of radioactive waste disposal.
The new method, published in Scientific Reports, could dramatically reduce the effective half-life (an indicator of the amount of time it takes to bring radioactive materials down to safe levels) of long-lived fission products (LLFPs) from hundreds of thousands of years to within a hundred years.
How to dispose of nuclear waste is one of the biggest dilemmas facing the world today. The issue concerns what to do with radioactive waste after uranium and plutonium have been recovered from spent nuclear fuel using reprocessing methods such as Plutonium Uranium Redox EXtraction (PUREX).
Although burying waste deep underground is widely viewed as the most viable option, a number of strategies are being explored to reduce the stockpile of depleted fuel. One of the most promising is the partitioning and transmutation (P&T) strategy. This involves separating fuel into minor actinides (MAs) and LLFPs followed by the transmutation of MAs and LLFPs into shorter-lived nuclides.
So far, the P&T strategy has been limited by the costly and cumbersome need to separate LLFP isotopes before they can undergo transmutation. Also, some LLFPs, owing to their small neutron capture cross sections, are not able to capture enough neutrons for effective transmutation to occur.
The new study led by Satoshi Chiba at Tokyo Tech shows that effective transmutation of LLFPs can be achieved in fast spectrum reactors without the need for isotope separation. By adding a moderator (or slowing-down material) called yttrium deuteride (YD2), the team found that LLFP transmutation efficiency increased in the radial blanket and shield regions of the reactor. The researchers say that this is due to the moderator's ability "to soften the neutron spectrum leaking from the core".
Chiba and his co-workers focused on six LLFPs: selenium-79, zirconium-93, technetium-99, palladium-107, iodine-129 and caesium-135. Calculations showed that the effective half-lives of these LLFPs could be drastically reduced so that total radiotoxicity at long cooling time domain will be efficiently reduced (see Figure).
In experiments of this kind, the support ratio (that is, the ratio of the transmutation rate to the production rate) is an important indicator of transmutation efficiency. The team showed that support ratios of over 1.0 were achieved for all six LLFPs tested, representing a vast improvement on previous findings.
Using their method, the researchers say that the 17,000 tons of LLFPs now in storage in Japan could potentially be disposed of using ten fast spectrum reactors. Their method also has the advantage of contributing to electricity generation and supporting efforts towards nuclear non-proliferation.
Long-lived fission products (LLFPs): Radioactive materials with long half-lives produced by nuclear fission. This study concerns the LLFPs selenium-79, zirconium-93, technetium-99, palladium-107, iodine-129 and caesium-135.
Minor actinides (MAs): Elements synthesized in nuclear fuel other than uranium and plutonium, such as neptunium, americium and curium.
Transmutation: A change induced by neutron capture that results in the conversion of LLFPs to short-lived or non-radioactive nuclides.
About Tokyo Institute of Technology
Tokyo Institute of Technology stands at the forefront of research and higher education as the leading university for science and technology in Japan. Tokyo Tech researchers excel in a variety of fields, such as material science, biology, computer science and physics. Founded in 1881, Tokyo Tech has grown to host 10,000 undergraduate and graduate students who become principled leaders of their fields and some of the most sought-after scientists and engineers at top companies. Embodying the Japanese philosophy of "monotsukuri," meaning technical ingenuity and innovation, the Tokyo Tech community strives to make significant contributions to society through high-impact research. https://www.titech.ac.jp/english/
Tohoku University was established in 1907 as Japan's third national university, and is proud to be recently ranked No.2 on the Times Higher Education 2017 list of top universities in Japan.
Tohoku University has a history of innovation and continues to lead in traditional fields of research, is committed to contributing to its local and global communities, and encourages academic-industry-government cooperation to help strengthen and develop new areas of research. https://www.tohoku.ac.jp/en/
About Tokyo City University
Tokyo City University's predecessor, Musashi Insitute of Technology was founded in 1929, by students seeking an ideal engineering education. The university promotes high-level engineering education and research, and educates engineers that contribute to society.
The university was renamed to Tokyo City University in 2009. In April 2013, the Faculty of Environmental and Information Science was split into the Faculty of Environmental Studies and the Faculty of Informatics, and now has six faculties and eighteen schools. Building on traditions of high quality specialist engineering education, we continue to educate graduates that will be sought after by society.
Tokyo Institute of Technology
Related Nuclear Articles:
The US Nuclear Regulatory Commission relied on faulty analysis to justify its refusal to adopt a critical measure for protecting Americans from nuclear-waste fires at dozens of reactor sites around the country, according to an article in the May 26 issue of Science magazine.
Extraordinary decontamination efforts are underway in areas affected by the 2011 nuclear accidents in Japan.
Scientists at Rice University, the University of Illinois at Urbana-Champaign and the University of Chile offer a glimpse into a possible new path toward the production of energy through nuclear fusion.
Researchers from Ludwig-Maximilians-Universitaet (LMU) Munich have, for the first time, measured the lifetime of an excited state in the nucleus of an unstable element.
The main type of nuclear fuel is the uranium oxide pellet composition.
Determining if an individual has handled nuclear materials is a challenge national defense agencies currently face.
The article, published recently in Open Chemistry may lead to the development of a process to remove uranium from wastewater at the front-end of the nuclear fuel cycle, or even extracting natural uranium from sea water.
In a new paper, University of California, Riverside theoretical physicist Flip Tanedo and his collaborators have made new progress towards unraveling a mystery in the beryllium nucleus that may be evidence for a fifth force of nature.
The atomic nucleus is highly complex. Understanding this complexity often requires a tremendous amount of computational power.
The theoretical view of the structure of the atom nucleus is not carved in stone.
Related Nuclear Reading:
The Doomsday Machine: Confessions of a Nuclear War Planner
by Daniel Ellsberg (Author)
Shortlisted for the 2018 Andrew Carnegie Medal for Excellence in Nonfiction
The San Francisco Chronicle’s Best of 2017 List
In These Times “Best Books of 2017”
Huffington Post’s Ten Excellent December Books List
LitHub’s “Five Books Making News This Week”
From the legendary whistle-blower who revealed the Pentagon Papers, an eyewitness exposé of the dangers of America's Top Secret, seventy-year-long nuclear policy that continues to this day.
Here, for the first time,... View Details
Command and Control: Nuclear Weapons, the Damascus Accident, and the Illusion of Safety
by Eric Schlosser (Author)
**The documentary Command and Control, directed by Robert Kenner, finds its origins in Eric Schlosser's book and continues to explore the little-known history of the management and safety concerns of America's nuclear aresenal.**
The documentary will air on PBS's American Experience on January 10th.
A myth-shattering exposé of America’s nuclear weapons
Famed investigative journalist Eric Schlosser digs deep to uncover secrets about the management of America’s nuclear arsenal. A groundbreaking account of accidents, near misses,... View Details
Nuclear War Survival Skills: Lifesaving Nuclear Facts and Self-Help Instructions
by Cresson H. Kearny (Author), Don Mann (Introduction), Edward Teller (Introduction), Dr. Eugene P. Wigner (Introduction)
A field-tested guide to surviving a nuclear attack, written by a revered civil defense expert.
This edition of Cresson H. Kearny’s iconic Nuclear War Survival Skills (originally published in 1979), updated by Kearny himself in 1987 and again in 2001, offers expert advice for ensuring your family’s safety should the worst come to pass. Chock-full of practical instructions and preventative measures, Nuclear War Survival Skills is based on years of meticulous scientific research conducted by Oak Ridge National Laboratory.
Featuring a new introduction by... View Details
U.S. Armed Forces Nuclear, Biological And Chemical Survival Manual
by Dick Couch (Author)
Military experts teach you how to survive an attack on American soil, from North Korean missiles to weaponized smallpoxNorth Korean nukes. Dirty bombs in train stations. Chemical warfare. Americans have more reasons than ever to be afraid. If a nuclear missile strikes, will you know what to do? If a nerve agent is released in your subway system or office building, will you be safe? The U.S. Armed Forces Nuclear, Biological and Chemical Survival Manual gives you the information you need to survive a terrorist attack. It contains the best practices of all the United... View Details
The Second Nuclear Age: Strategy, Danger, and the New Power Politics
by Paul Bracken (Author)
A leading international security strategist offers a compelling new way to "think about the unthinkable."
The cold war ended more than two decades ago, and with its end came a reduction in the threat of nuclear weapons―a luxury that we can no longer indulge. It's not just the threat of Iran getting the bomb or North Korea doing something rash; the whole complexion of global power politics is changing because of the reemergence of nuclear weapons as a vital element of statecraft and power politics. In short, we have entered the second nuclear age.
In this provocative... View Details
Nagasaki: Life After Nuclear War
by Susan Southard (Author)
“[A] reminder of just how horrible nuclear weapons are.”—The Wall Street Journal
“A devastating read that highlights man’s capacity to wreak destruction, but in which one also catches a glimpse of all that is best about people.”—San Francisco Chronicle
“A poignant and complex picture of the second atomic bomb’s enduring physical and psychological tolls. Eyewitness accounts are visceral and haunting. . . . But the book’s biggest achievement is its treatment of the aftershocks in the decades since 1945.” —The... View Details
Atomic Accidents: A History of Nuclear Meltdowns and Disasters: From the Ozark Mountains to Fukushima
by James Mahaffey (Author)
A gripping narrative of nuclear mishaps and meltdowns around the globe, all of which have proven pivotal to the advancement of nuclear science.
From the moment radiation was discovered in the late nineteenth century, nuclear science has had a rich history of innovative scientific exploration and discovery, coupled with mistakes, accidents, and downright disasters.
Mahaffey, a long-time advocate of continued nuclear research and nuclear energy, looks at each incident in turn and analyzes what happened and why, often discovering where scientists went wrong... View Details
Nuclear Weapons: A Very Short Introduction (Very Short Introductions)
by Joseph M. Siracusa (Author)
Despite not having been used in anger since Hiroshima and Nagasaki, the atomic bomb is still the biggest threat that faces us in the 21st century. As Bill Clinton's first secretary of defense, Les Aspin, aptly put it, "The Cold War is over, the Soviet Union is no more. But the post-Cold War world is decidedly not post-nuclear." For all the effort to reduce nuclear stockpiles to zero, it seems that the bomb is here to stay. This Very Short Introduction reveals why.
The history and politics of the bomb are explained: from the technology of nuclear weapons, to the revolutionary... View Details
The Evolution of Nuclear Strategy, Third Edition
by Lawrence Freedman (Author)
First published twenty years ago, Lawrence Freedman's Evolution of Nuclear Strategy was immediately acclaimed as the standard work on the history of attempts to cope militarily and politically with the terrible destructive power of nuclear weapons. It has now been rewritten, drawing on a wide range of new research, and updated to take account of the period following the end of the cold war, taking the story to contemporary arguments about missile defence. View Details
The Spread of Nuclear Weapons: An Enduring Debate (Third Edition)
by Scott Douglas Sagan (Author), Kenneth N. Waltz (Author)
A long-time staple of International Relations courses, this new edition continues the important discussion of nuclear proliferation, while looking at the regions and issues now at the forefront of the nuclear question.Over the past fifteen years, The Spread of Nuclear Weapons has been a staple in International Relations courses because of its brevity and crystal-clear explanations. The new edition, An Enduring Debate, continues the important discussion of nuclear proliferation and the dangers of a nuclear-armed world. With new chapters on the... View Details