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Category: nuclear energy – Page 115

Assembly of the Plasma Liner Experiment (PLX) at Los Alamos National Laboratory is well underway with the installation of 18 of 36 plasma guns in an ambitious approach to achieving controlled nuclear fusion (Figure 1). The plasma guns are mounted on a spherical chamber, and fire supersonic jets of ionized gas inward to compress and heat a central gas target that serves as fusion fuel. In the meantime, experiments performed with the currently installed plasma guns are providing fundamental data to create simulations of colliding plasma jets, which are crucial for understanding and developing other controlled fusion schemes.

Most experiments employ either magnetic confinement, which relies on powerful magnetic fields to contain a fusion , or inertial confinement, which uses heat and compression to create the conditions for fusion.

The PLX machine combines aspects of both magnetic confinement fusion schemes (e.g. tokamaks) and inertial confinement machines like the National Ignition Facility (NIF). The hybrid approach, although less technologically mature than pure magnetic or inertial confinement concepts, may offer a cheaper and less complex fusion reactor development path. Like tokamaks, the fuel plasma is magnetized to help mitigate losses of particles and thermal energy. Like inertial machines, a heavy imploding shell (the plasma ) rapidly compresses and heats the fuel to achieve fusion conditions. Instead of NIF’s array of high-power lasers driving a solid capsule, PLX relies on supersonic plasma jets fired from plasma guns.

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Quantum simulation plays an irreplaceable role in diverse fields, beyond the scope of classical computers. In a recent study, Keren Li and an interdisciplinary research team at the Center for Quantum Computing, Quantum Science and Engineering and the Department of Physics and Astronomy in China, U.S. Germany and Canada. Experimentally simulated spin-network states by simulating quantum spacetime tetrahedra on a four-qubit nuclear magnetic resonance (NMR) quantum simulator. The experimental fidelity was above 95 percent. The research team used the quantum tetrahedra prepared by nuclear magnetic resonance to simulate a two-dimensional (2-D) spinfoam vertex (model) amplitude, and display local dynamics of quantum spacetime. Li et al. measured the geometric properties of the corresponding quantum tetrahedra to simulate their interactions. The experimental work is an initial attempt and a basic module to represent the Feynman diagram vertex in the spinfoam formulation, to study loop quantum gravity (LQG) using quantum information processing. The results are now available on Communication Physics.

Classical computers cannot study large quantum systems despite successful simulations of a variety of physical systems. The systematic constraints of classical computers occurred when the linear growth of quantum system sizes corresponded to the exponential growth of the Hilbert Space, a mathematical foundation of quantum mechanics. Quantum physicists aim to overcome the issue using quantum computers that process information intrinsically or quantum-mechanically to outperform their classical counterparts exponentially. In 1982, Physicist Richard Feynman defined quantum computers as quantum systems that can be controlled to mimic or simulate the behaviour or properties of relatively less accessible quantum systems.

In the present work, Li et al. used nuclear magnetic resonance (NMR) with a high controllable performance on the quantum system to develop simulation methods. The strategy facilitated the presentation of quantum geometries of space and spacetime based on the analogies between nuclear spin states in NMR samples and spin-network states in quantum gravity. Quantum gravity aims to unite the Einstein gravity with quantum mechanics to expand our understanding of gravity to the Planck scale (1.22 × 1019 GeV). At the Planck scale (magnitudes of space, time and energy) Einstein gravity and the continuum of spacetime breakdown can be replaced via quantum spacetime. Research approaches toward understanding quantum spacetimes are presently rooted in spin networks (a graph of lines and nodes to represent the quantum state of space at a certain point in time), which are an important, non-perturbative framework of quantum gravity.

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The patent application for a “Plasma Compression Fusion Device” was applied for in March last year. It read, “Application filed by US Secretary of Navy.” The patent application was published in September this year. Under discussion is a compact fusion reactor.

The focus is on a compact that measures between 0.3 to 2 meters in diameter. As of October 15, the application status was listed as pending. The inventor named in the was Salvatore Pais.

As described in The War Zone, the could “pump out absolutely incredible amounts of power in a small space.”

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Cadmium nuclei take on multiple shapes at low excitation energies, a discovery that overturns a long-accepted tenet of nuclear structure.

Atomic nuclei take on excited states when they vibrate, rotate, or when their constituent nucleons exchange one nuclear shell for another. In nuclei with nearly filled nuclear shells, it has long been thought that low-energy excitations were due exclusively to different patterns of vibration around a spherical shape: only in rare, high-energy excitations were these nuclei expected to assume more exotic shapes. Now, Paul Garrett, of the University of Guelph in Canada, and colleagues have found that the lowest-energy excited states of cadmium-110 and cadmium-112—once considered textbook examples of spherical vibration—are instead due to the rotation of various nonspherical shapes. The result is also the best evidence to date that a stable nucleus like cadmium can assume multiple shapes—all previously studied nuclei with coexisting shapes have been radioactive.

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The Netherlands’ Nuclear Research and Consultancy Group (NRG) has completed a major milestone irradiation test of molten nuclear fuel salts in its High Flux Reactor at Petten 37 mi (60 km) north of Amsterdam. The first test of its kind since the ones carried out at Oak Ridge, Tennessee in the 1960s, its purpose is to learn more about the safe operation of a future Molten Salt Reactor (MSR).

First developed in the United States in the 1950s and ’60s, MSRs differ from conventional light-water nuclear reactors in a number of significant ways that make them potentially a safer and more efficient alternative. This is because, though a light-water reactor and an MSR work on the same principle of nuclear fission, they have a fundamentally different engineering design.

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Result: Some 6 million pounds of spent nuclear waste, generated over a half-century, remain in seismically sensitive spots on the California coast, at both San Onofre and Diablo Canyon. That’s among some 200 million pounds of radioactive waste languishing at 80 reactor sites in 35 states from sea to shining sea, where it will remain for the foreseeable future.

“We’ve so tainted this whole process because of fear,” said James Conca, a controversial nuclear energy advocate with a doctorate in geochemistry from the California Institute of Technology. “You get everyone so scared you never do anything.

”Look, we know where to put this stuff,” he said. ”We’ve known for 60 years. We have an operating deep geologic repository right now — but it’s only for bomb waste.”

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A molten salt reactor (MSR) is a type of nuclear reactor that uses liquid fuel instead of the solid fuel rods used in conventional nuclear reactors. Using liquid fuel provides many advantages in safety and simplicity of design.

The figure above shows one type of MSR design. As shown towards the left, the reactor contains “fuel salt”, which is fuel (such as uranium-235) dissolved in a mixture of molten fluoride salts. After a fission chain reaction starts in the reactor, the rate of fission stabilizes once the fuel salt reaches around 700 degrees Celsius. If the reactor gets hotter than 700 degrees, the resulting expansion of the fuel salt pushes some of the fuel into the circulation loop; this, in turn, decreases the fission rate (since fission cannot be maintained in the loop), causing the fuel to cool.

Unlike conventional reactors, the rate of fission in an MSR is inherently stable. Nonetheless, should the fuel salt become too hot to operate safely, a freeze plug (made of salts kept solid by a cooling fan) below the reactor will melt and the liquid content of the reactor will flow down into emergency dump tanks where it cannot continue to fission, thus allowing it to cool safely.

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  • The floating power unit Akademik Lomonosov has arrived at the port of its permanent location in Pevek, Chukotka, in Russia’s Far East, where it is being docked to start operations by the end of this year.
  • Once commissioned, it will become the world’s first operational nuclear power plant based on small modular reactors (SMRs) technology and a ‘working prototype’ for reliable source of low-carbon energy supply in remote areas.

“It’s maybe one small step for sustainable development in the Arctic, but it’s a giant leap for the decarbonisation of remote off-grid areas, and a watershed in the development of small modular nuclear power plants in the world,” said Rosatom CEO, Alexey Likhachev.

Director General of the World Nuclear Association, Agneta Rising, commented: “To meet the nuclear industry’s Harmony goal of supplying at least 25% of the world’s electricity by 2050 we will need to bring the benefits of nuclear energy to more people in a wider range of locations.

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