Archive for the ‘nuclear energy’ category: Page 61

Jun 12, 2020

Black hole model reveals star collapse without bright explosion

Posted by in categories: cosmology, nuclear energy, physics

A team of scientists, including Chief Investigator Ilya Mandel from the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) at Monash University, recently studied what happens to rotating massive stars when they reach the end of their lives.

Stars produce energy by fusing lighter elements into heavier ones in their core: hydrogen into helium, then helium into carbon, oxygen, and so on, up to . The energy produced by this also provides pressure support inside the star, which balances the force of gravity and allows the star to remain in equilibrium.

This process stops at iron. Beyond iron, energy is required to sustain fusion rather than being released by fusion. A heavy iron star core contracts under gravity, creating a neutron star, or if it is heavy enough, a black hole. Meanwhile, the outer layers of the star explode in a brilliant flash, observable as a supernova. However, some massive stars seem to completely disappear without any explosion. Theories suggest that these massive stars completely collapse into , but is that possible?

Jun 9, 2020

Novel photovoltaics generate electrical power from thermal sources

Posted by in categories: chemistry, nuclear energy

Devices based on photon-assisted tunnelling could harvest energy from nuclear power stations, chemical manufacturing facilities and other sources of waste heat.

Jun 8, 2020

Transformational Challenge Nuclear Reactor: Microreactor Built Using 3D Printing

Posted by in categories: 3D printing, nuclear energy

At the Department of Energy Manufacturing Demonstration Facility at ORNL, this part for a scaled-down prototype of a reactor was produced for industry partner Kairos Power. Credit: Kairos Power.

Jun 3, 2020

73 Years After Its Debut, The Doomsday Clock Is 100 Seconds From Midnight

Posted by in categories: existential risks, military, nuclear energy

73 years ago, the same scientists who had helped to begin the atomic age set a “doomsday clock” for humanity. It first appeared on the cover of the June 1947 issue of the Bulletin of the Atomic Scientists as a dire warning about the nuclear rivalry between the U.S. and the Soviet Union. At that moment, the Bulletin estimated that we stood at about 7 minutes to midnight, which represented nuclear apocalypse.

The Doomsday Clock wasn’t – and still isn’t – a precise countdown to the end of all things. It’s a metaphor for how dangerous the global situation seems to be at a given moment, in the very well-informed but also subjective opinion of the Bulletin’s board of directors. In June 1947, things looked dire. The U.S. had dropped a pair of atomic bombs on Japan less than two years before; when the Bulletin of the Atomic Scientists first published the Doomsday Clock image, researchers were still studying the aftermath of those bombs. Meanwhile, the Soviet Union was hard at work on its own atomic program, and was just a couple of years away from testing its first atomic bomb in 1949.

Through the Cold War and in the decades since, the clock’s minute hand has moved about two dozen times. In September 1953, it stood at two minutes to midnight, following Russia’s August 1953 hydrogen bomb test – which in turn had followed a U.S. hydrogen bomb test in November 1952. Those tests meant the two feuding superpowers each had much more powerful new weapons with which to destroy each other; the tests also heightened the sense of life-or-death competition that made it more likely that someone would decide to use those terrible new bombs.

Jun 1, 2020

ARC reactor design uses superconducting magnets to draw fusion power closer

Posted by in categories: bioengineering, military, nuclear energy, particle physics

Circa 2015

Fusion power can seem a bit like the last bus at night; it’s always coming, but never arrives. MIT is working to change that with a new compact tokamak fusion reactor design based on the latest commercially available magnetic superconductor technology. The ARC (affordable, robust, compact) reactor design promises smaller, cheaper reactors that could make fusion power practical within 10 years.

A commercially viable fusion reactor has been the Holy Grail of engineering since the 1950s, with the potential to turn almost all other major electricity sources into an historical footnote overnight. If perfected, it would essentially be an inexhaustible source of power, impacting on almost every aspect of life, from the environment to global politics. The trick is making it practical.

Continue reading “ARC reactor design uses superconducting magnets to draw fusion power closer” »

May 31, 2020

ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets

Posted by in categories: nuclear energy, science

Circa 2015

The affordable, robust, compact (ARC) reactor is the product of a conceptual design study aimed at reducing the size, cost, and complexity of a combined fusion nuclear science facility (FNSF) and demonstration fusion Pilot power plant. ARC is a ∼200–250 MWe tokamak reactor with a major radius of 3.3 m, a minor radius of 1.1 m, and an on-axis magnetic field of 9.2 T. ARC has rare earth barium copper oxide (REBCO) superconducting toroidal field coils, which have joints to enable disassembly. This allows the vacuum vessel to be replaced quickly, mitigating first wall survivability concerns, and permits a single device to test many vacuum vessel designs and divertor materials. The design point has a plasma fusion gain of Qp ≈ 13.6, yet is fully non-inductive, with a modest bootstrap fraction of only ∼63%. Thus ARC offers a high power gain with relatively large external control of the current profile. This highly attractive combination is enabled by the ∼23 T peak field on coil achievable with newly available REBCO superconductor technology. External current drive is provided by two innovative inboard RF launchers using 25 MW of lower hybrid and 13.6 MW of ion cyclotron fast wave power. The resulting efficient current drive provides a robust, steady state core plasma far from disruptive limits. ARC uses an all-liquid blanket, consisting of low pressure, slowly flowing fluorine lithium beryllium (FLiBe) molten salt. The liquid blanket is low-risk technology and provides effective neutron moderation and shielding, excellent heat removal, and a tritium breeding ratio ≥ 1.1. The large temperature range over which FLiBe is liquid permits an output blanket temperature of 900 K, single phase fluid cooling, and a high efficiency helium Brayton cycle, which allows for net electricity generation when operating ARC as a Pilot power plant.

May 30, 2020

The Navy’s Patent for a Compact Nuclear Fusion Reactor Is Wild

Posted by in categories: nuclear energy, policy, space travel

Circa 2019

Scientists have longed to create the perfect energy source. Ideally, that source would eventually replace greenhouse gas-spewing fossil fuels, power cars, boats, and planes, and send spacecraft to remote parts of the universe. So far, nuclear fusion energy has seemed like the most likely option to help us reach those goals.

The big problem? It’s difficult to harness, and we’re nowhere near producing it at the scales we need in order to cause a seismic shift in energy policy. That’s why teams of researchers across the world are racing to improve our understanding of this reaction.

Continue reading “The Navy’s Patent for a Compact Nuclear Fusion Reactor Is Wild” »

May 30, 2020

Oil giant joins Bill Gates-backed nuclear fusion plan for ‘game-changing zero-carbon energy’

Posted by in category: nuclear energy

Equinor among latest round of investors in MIT spin-off that aims to help show ‘net energy gain’ nuclear fusion by 2025.

May 30, 2020

Artificial intelligence is energy-hungry—new hardware could curb its appetite

Posted by in categories: biotech/medical, nuclear energy, robotics/AI

To just solve a puzzle or play a game, artificial intelligence can require software running on thousands of computers. That could be the energy that three nuclear plants produce in one hour.

A team of engineers has created hardware that can learn skills using a type of AI that currently runs on platforms. Sharing intelligence features between hardware and software would offset the energy needed for using AI in more advanced applications such as self-driving cars or discovering drugs.

“Software is taking on most of the challenges in AI. If you could incorporate intelligence into the circuit components in addition to what is happening in software, you could do things that simply cannot be done today,” said Shriram Ramanathan, a professor of materials engineering at Purdue University.

May 27, 2020

Mobile Nuclear Microreactor Development: A Military-Civilian Symbiosis

Posted by in categories: computing, military, nuclear energy

EXECUTIVE SUMMARY: The US Department of Defense has been working with American companies for the past year on a project to develop a prototype for a portable nuclear microreactor, a device intended for use by the US military in security scenarios around the world. The US Department of Energy is also involved in the project, with the aim of providing electricity to remote sites that are difficult to link to the grid. The project thus represents a symbiosis between military and civilian technological development.

A symbiotic relationship between military and civilian aspects of technological development gained momentum in the US after the end of WWII. This was particularly visible among applications in the communication, computing, and aerospace fields, but was also present in the field of nuclear technology. Some technology projects were presented as dual-use in order to justify the cost of their development.

One example of nuclear energy symbiosis was the development of nuclear power-generating reactors. By 1956, more than a decade after the destruction of the Japanese cities of Hiroshima and Nagasaki by nuclear bombs, only the UK’s Calder Hall nuclear power plant, which had four reactors each producing 60 MW electricity (MWe), was in operation. However, as of December 2019, 443 nuclear power generators were operating worldwide, with a total output of 395 gigawatts electric (GWe)—an average output of nearly 900 MWe per reactor.

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