Nuclear Fusion

Nuclear Fusion

If two light nuclei are combined to make a heavier nucleus, that is fusion. For all atoms produced lighter than iron, large amounts of energy is given off. The sun and all other stars are powered by nuclear fusion. The first and most common reaction is a star's life cycle is Hydrogen isotopes producing Helium.

In man made fusion, the easiest reaction is:

Deuterium + Tritium ---> Helium

The deuterium is separated from water. Tritium is made by firing neutrons at Lithium to produce Tritium + Helium. Tritium has a half life of 12 years so doesn't occur in nature.

This reaction has only been briefly achieved. The neutron flux is very high and irradiates the equipment so that it needs to be remotely handled and disposed of as nuclear waste. It is not as long lived as fission waste.

What is never mentioned is whether we have enough lithium. It would be destroyed, transmuted. Would there be enough for batteries?

It is a long way from commercial reality.

Wikipedia: Fusion power

There are various approaches to produce fusion:

None are producing commercial power

Tokamak

Tokamaks were originally discovered in Soviet Union but have been adopted by researchers around the globe.

The gas is heated until its electrons are removed and becomes an electriclly charged plasma. Magnetic fields produced by the coils surrounding the plasma can squeeze the confining the hot plasma away from surrounding material walls. The plasma is heated to a few hundred million degrees Kelvin. At his temperature the particles are moving fast enough to collide with enough force to fuse together.

 

Helion

Helion claims they are making a fusion engine 1,000 times smaller, over 500 times cheaper, and  10 times faster than other projects.

Helion Energy co-founder John Slough in the Redmond, Wash., skunkworks. Slough says his reactor's simplicity and low cost give him a huge advantage in the fusion power race.

Photio: John Keatley Source: Popular Mechanics


From​ www.helionenergy.com

Magneto-Inertial Fusion: By combining the stability of steady magnetic fusion and the heating of pulsed inertial fusion, a commercially practical system has been realized that is smaller and lower cost than existing programs.
Modular, Distributed Power: A container sized, 50 MW module for base load power generation.
Self-Supplied Helium 3 Fusion: Pulsed, D-He3 fusion simplifies the engineering of a fusion power plant, lowers costs, and is even cleaner than traditional fusion.
Magnetic Compression: Fuel is compressed and heated purely by magnetic fields operated with modern solid state electronics. This eliminates inefficient, expensive laser, piston, or beam techniques used by other fusion approaches.
Direct Energy Conversion: Enabled by pulsed operation, efficient direct conversion decreases plant costs and fusion’s engineering challenges.
Safe: With no possibility of melt-down, or hazardous nuclear waste, fusion does not suffer the drawbacks that make fission an unattractive alternative.

The helion is the name for the He3 nucleus. The He4 nucleus is called an alpha particle.

Helion Energy, a Redmond, Washington-based company that claims it will build a 50-MWe pilot of its “Fusion Engine” by 2019. 

Helion is considering adapting its reactor to burn up nuclear waste in order to provide revenue. It's easier from a technical standpoint than using fusion to produce energy. Helion calculates 50 fusion engines could incinerate the entire U.S. stockpile of nuclear waste in 20 years. 

 

The Fusion Engine provides energy in two ways. Like in a fission reactor, the energy of the scattered neutrons gives off heat that ultimately drives a turbine. Helion is also developing a technique that directly converts energy to electricity. The direct conversion will provide about 70 percent of the outgoing electricity.

More: The Weinberg Foundation

General Fusion

General Fusion’s Magnetized Target Fusion system uses a sphere, filled with molten lead-lithium that is pumped to form a vortex.  On each pulse, magnetically-confined plasma is injected into the vortex. Around the sphere, an array of pistons impact and drive a pressure wave into the centre of the sphere, compressing the plasma to fusion conditions.

General Fusion will be constructing a full scale prototype system.  The prototype will be designed for single pulse testing, demonstrating full net energy gain on each pulse.

Magnetized target fusion (MTF) is a hybrid between magnetic fusion and inertial confinement fusion.  In MTF, a compact toroid, or donut-shaped magnetized plasma, is compressed mechanically by an imploding conductive shell, heating the plasma to fusion conditions.

 

Muon catalysed fusion

First observed in the 1950s, muon catalysed fusion is a well known scientific process where a subatomic particle known as a muon* captures two hydrogen atoms and forces them to fuse, resulting in energetic particle release and helium.

 

Scientists have been producing nuclear fusion reactions from muon catalysed fusion for decades – just not consistently or in sufficient volumes for it to be considered a viable energy source.

Star Scientific is working towards overcoming these hurdles by perfecting a world-first technique to economically and constantly produce pions, which immediately decay into muons – an innovation that would finally make sustained, controlled muon catalysed fusion a reality.

Source

Ref: Wikipedia

*Muons are the decayed products of a particle called a pion, and are the catalysts in the fusion of two hydrogen isotopes, a process which releases copious amounts of energy. The beauty of the muon is that it acts very much like an electron whose job it is to bond atoms together into molecules. Since a muon is 207 times heavier than an electron, it bumps the electron out of the way and replaces it.

Because the orbit of the heavier muon is much closer, it causes the atoms in the molecule to draw closer until the natural repelling force is overcome and a strong nuclear force brings the atoms together – causing them to fuse. This process kicks the muon out to do its job all over again some 300 times. This fusion gives us energetic neutrons, which are easily converted to heat in a pressurised water reactor – resulting in steam which can be harnessed to create electricity.

Lockheed Martin

Their team has completed much of the theoretical work  over the last four years, and have begun the first experiments. 

They claim they can heat and ignite the plasma with under a kilowatt of power.

The plan is to make a nuclear fusion plant to fit on a truck.

They estimate it will be ready by 2024.

 

Aneutronic fus​ion

Aneutronic fusion is any form of fusion power where neutrons carry no more than 1% of the total released energy.[1] The most-studied fusion reactions release up to 80% of their energy in neutrons. Successful aneutronic fusion would greatly reduce problems associated with neutron radiation such as ionizing damage, neutron activation, and requirements for biological shielding, remote handling, and safety.

Some proponents also see a potential for dramatic cost reductions by converting energy directly to electricity. However, the conditions required to harness aneutronic fusion are much more extreme than those required for the conventional deuterium–tritium (DT) fuel cycle.

Wikipedia

Various organisations are working on this.

Candidate aneutronic reactions

There are a few fusion reactions that have no neutrons as products on any of their branches. Those with the largest cross sections are these:

2D + 3He →        4He  +  1p + 18.3 MeV
2D +  6Li →     2  4He    +  22.4 MeV
1p +   6Li →        4He  +   3He + 4.0 MeV
3He + 6Li →     2 4He   +   1p + 16.9 MeV
3He + 3He →      4He   + 2 1p + 12.86 MeV
1p +    7Li →   2  4He   + 17.2 MeV
1p +   11B →  3  4He   + 8.7 MeV
1p +   15N  →    12C  + 4He + 5.0 MeV[2]
 

The idea is to have the particles collided and fuse.

E.g. Crossfire

 

Image credit: from the Levi et al. paper.

Cold fusion or Low Energy Nuclear Reaction LENR

 

The cold fusion effect has had a rocky ride. the first claim was seen as a fake, but now is being researched by respectable groups.

(I cannot yet tell if it is real or fake - John Davis)

www.coldfusionnw.org

An Italian researcher Rossi has claimed success in combining Ni with H. Then using very high terahertz radiation they transmute to copper. NASA researchers are quoted as combining C + H to become N.

The current wave of interest was sparked by Italian inventor Andrea Rossi, who showed off his Energy Catalyser or E-Cat in 2011. Rossi claimed that his reactor produced hundreds of kilowatts, and after the demonstration, he went into partnership with an undisclosed US industrial partner. A confidentiality agreement apparently prevents him from giving any details of his work. 

Other researchers combine Palladium with deuterium with electricity.

The electricity forces the deuterium into the palladium. The theory is that there is a nuclear fusion reaction, at a slow rate, and without dangerous radiation.

Scientists like to call it a nuclear effect rather than cold fusion. At least 20 labs working independently have published reports of excess heat - heat up to 25 times greater than the electricity going in. 

One of the main problems is that sometimes it works, and sometimes it doesn't.

Some scientists believe it works, other believe it doesn't.

News

Observation of abundant heat production from a reactor device and of isotopic changes in the fuel

Giuseppe Levi
Bologna University, Bologna, Italy

Evelyn Foschi

Bologna, Italy

Bo Höistad, Roland Pettersson and Lars Tegnér
Uppsala University, Uppsala, Sweden

Hanno Essén
Royal Institute of Technology, Stockholm, Sweden

Abstract

“New results are presented from an extended experimental investigation of anomalous heat production in a special type of reactor tube operating at high temperatures. The reactor, named E-Cat, is charged with a small amount of hydrogen-loaded nickel powder plus some additives, mainly Lithium. The reaction is primarily initiated by heat from resistor coils around the reactor tube. Measurements of the radiated power from the reactor were performed with high-resolution thermal imaging cameras. The measurements of electrical power input were performed with a large bandwidth three-phase power analyzer. Data were collected during 32 days of running in March 2014. The reactor operating point was set to about 1260 oC in the first half of the run, and at about 1400 °C in the second half. The measured energy balance between input and output heat yielded a COP factor of about 3.2 and 3.6 for the 1260 oC and 1400 oC runs, respectively. The total net energy obtained during the 32 days run was about 1.5 MWh. This amount of energy is far more than can be obtained from any known chemical sources in the small reactor volume.

A sample of the fuel was carefully examined with respect to its isotopic composition before the run and after the run, using several standard methods: XPS, EDS, SIMS, ICP-MS and ICP-AES. The isotope composition in Lithium and Nickel was found to agree with the natural composition before the run, while after the run it was found to have changed substantially. Nuclear reactions are therefore indicated to be present in the run process, which however is hard to reconcile with the fact that no radioactivity was detected outside the reactor during the run. “

-Source

Summary of nuclear energy - http://www.energy-without-carbon.org/NuclearSummary

Radio active decay - http://www.energy-without-carbon.org/RadioActiveDecay

Nuclear Fission - http://www.energy-without-carbon.org/NuclearFission

 

   
   

 

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