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Nuclear Fusion
Nuclear fusion is the phenomenon in which multiple atomic nuclei combine to form a single, larger nucleus. Fusion mostly occurs under extreme conditions, due to the large amount of energy it requires. Thus, examples of fusion tend to be exotic; such as stellar nucleosynthesis, the creation of new elements, and thermonuclear weapons.
521 Questions
Nuclear energy is the energy in the nucleus, or core, of an atom. Atoms are tiny units that make up all matter in the universe. Energy is what holds the nucleus together. There is a huge amount of power in an atom's dense nucleus. Nuclear energy is seen when nuclear fusions or fissions happen.
Some nuclei, notably U235 and Pu239, can be made to cause a chain reaction where neutrons are produced in nuclear fission, and propogate more subsequent neutrons so that a steady rate of fissions can be achieved. Each fission releases an amount of energy in the form of heat, which is then used in generating plant similar to that in a fossil fuelled power plant.
Why does helium fusion require a higher temperature than hydrogen fusion?
They are both in period 1, so have their valence electrons in the first energy level. However, helium has 2 protons in the nucleus holding on to those electrons. Hydrogen has only 1 proton holding the electrons. Thus it takes more energy to remove an electron from helium than from hydrogen.
I am what is being investigated to contain fusion reaction?
You are most likely referring to a magnetic confinement fusion device, such as a tokamak or a stellarator. These devices use powerful magnetic fields to confine and control high-temperature plasma, enabling the conditions necessary for a controlled fusion reaction to occur. Scientists and researchers study and investigate these devices in order to develop a viable and sustainable method of achieving nuclear fusion as a clean and abundant source of energy.
Which of the following could result from the fusion of carbon with itself?
Carbon fusion requires a temperature of 500 million K and a density of 3 million g/cc. It follows three different processes:
- 12C + 12C --> 20Ne + 4He (4.62 MeV)
- 12C + 12C --> 23Na + p (2.24 MeV)
- 12C + 12C --> 23Mg + n (-2.62 MeV)
Why does nuclear fusion occur in the core?
At the core of a star, the sun for example, the pressure due to gravity is greatest and gives the best conditions for fusion to start. Heat then flows outwards in all directions from the core.
Fission and fusion of nuclear power plant?
Fission is the splitting of an atom, fusion is the joining of 2 atoms into one. In most fission, neutrons are bomabarded at the nucleus of uranium or plutonium and this causes a ripple effect of more neutons being released from the fuel. The process generates large amounts of heat which is either used for destruction or steam engines. Fusion most often occurs with 2 Hydrogens being fused together to form helium. Deuterium (Hydrogen with a neutron and proton instead of just a proton) and tritium (one proton and two neutrons) are high energy atoms that are used in testing nuclear fusion. Our star (the sun) is based, like most stars, on Hydrogen being fused to generate heat and Helium.
Does nuclear fusion produce more radioactive waste than nuclear fision?
The waste from coal power stations has virtually no radioactive waste where as a
nuclear plants waste is nearly all toxic.
Completely Wrong. All coal waste is toxic. Coal fired power plants chuck out all the radioactive elements that were in the coal that was burned. This is fairly old news from the 70's. Excellent source: http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html .
More facts that are totally ignored by the media as governors and industrial groups lobby to continue to launch toxic, hazardous and poisonous elements and compounds into the air from the stacks, and onto the land downwind.
The following is quoted. There is no copyright on this article at this website. Thanks to ORNL.
Web site provided by Oak Ridge National Laboratory's Communications and External Relations
ORNL is a multi-program research and development facility managed by UT-Battelle for the US Department of Energy
"Because existing coal-fired power plants vary in size and electrical output, to calculate the annual coal consumption of these facilities, assume that the typical plant has an electrical output of 1000 megawatts. Existing coal-fired plants of this capacity annually burn about 4 million tons of coal each year. Further, considering that in 1982 about 616 million short tons (2000 pounds per ton) of coal was burned in the United States (from 833 million short tons mined, or 74%), the number of typical coal-fired plants necessary to consume this quantity of coal is 154.
Using these data, the releases of radioactive materials per typical plant can be calculated for any year. For the year 1982, assuming coal contains uranium and thorium concentrations of 1.3 ppm and 3.2 ppm, respectively, each typical plant released 5.2 tons of uranium (containing 74 pounds of uranium-235) and 12.8 tons of thorium that year. Total U.S. releases in 1982 (from 154 typical plants) amounted to 801 tons of uranium (containing 11,371 pounds of uranium-235) and 1971 tons of thorium. These figures account for only 74% of releases from combustion of coal from all sources.
Releases in 1982 from worldwide combustion of 2800 million tons of coal totaled 3640 tons of uranium (containing 51,700 pounds of uranium-235) and 8960 tons of thorium.
Based on the predicted combustion of 2516 million tons of coal in the United States and 12,580 million tons worldwide during the year 2040, cumulative releases for the 100 years of coal combustion following 1937 are predicted to be:
U.S. release (from combustion of 111,716 million tons):
Uranium: 145,230 tons (containing 1031 tons of uranium-235)
Thorium: 357,491 tons
Worldwide release (from combustion of 637,409 million tons):
Uranium: 828,632 tons (containing 5883 tons of uranium-235)
Thorium: 2,039,709 tons
Radioactivity from Coal Combustion
The main sources of radiation released from coal combustion include not only uranium and thorium but also daughter products produced by the decay of these isotopes, such as radium, radon, polonium, bismuth, and lead. Although not a decay product, naturally occurring radioactive potassium-40 is also a significant contributor.
According to the National Council on Radiation Protection and Measurements (NCRP), the average radioactivity per short ton of coal is 17,100 millicuries/4,000,000 tons, or 0.00427 millicuries/ton. This figure can be used to calculate the average expected radioactivity release from coal combustion. For 1982 the total release of radioactivity from 154 typical coal plants in the United States was, therefore, 2,630,230 millicuries.
Thus, by combining U.S. coal combustion from 1937 (440 million tons) through 1987 (661 million tons) with an estimated total in the year 2040 (2516 million tons), the total expected U.S. radioactivity release to the environment by 2040 can be determined. That total comes from the expected combustion of 111,716 million tons of coal with the release of 477,027,320 millicuries in the United States. Global releases of radioactivity from the predicted combustion of 637,409 million tons of coal would be 2,721,736,430 millicuries.
For comparison, according to NCRP Reports No. 92 and No. 95, population exposure from operation of 1000-MWe nuclear and coal-fired power plants amounts to 490 person-rem/year for coal plants and 4.8 person-rem/year for nuclear plants. Thus, the population effective dose equivalent from coal plants is 100 times that from nuclear plants. For the complete nuclear fuel cycle, from mining to reactor operation to waste disposal, the radiation dose is cited as 136 person-rem/year; the equivalent dose for coal use, from mining to power plant operation to waste disposal, is not listed in this report and is probably unknown.
...
Although trace quantities of radioactive heavy metals are not nearly as likely to produce adverse health effects as the vast array of chemical by-products from coal combustion, the accumulated quantities of these isotopes over 150 or 250 years could pose a significant future ecological burden and potentially produce adverse health effects, especially if they are locally accumulated. Because coal is predicted to be the primary energy source for electric power production in the foreseeable future, the potential impact of long-term accumulation of by-products in the biosphere should be considered. "
Personally, more concerned about the complete waste slate, but the radioactive portion always deserves mention.
Simple search by high school chemistry students found the West Virginia coal trace elements shown in an average ppm for nearly 800 samples.
Antimony (Sb)
1.02
Arsenic (As)
17.13
Barium (Ba)
109.86
Beryllium (Be)
2.57
Bismuth (Bi)
0.32
Boron (B)
20.01
Bromine (Br)
23.88
Cadmium (Cd)
0.096
Cerium (Ce)
16.88
Cesium (Cs)
1.15
Chlorine (Cl)
959
Chromium (Cr)
17.85
Cobalt (Co)
7.41
Copper (Cu)
20.4
Dysprosium (Dy)
2.03
Erbium (Er)
1.09
Europium (Eu)
0.33
Fluorine (F)
62.68
Gadolinium (Gd)
1.46
Gallium (Ga)
6.45
Germanium (Ge)
3.09
Gold (Au)
6.062
Hafnium (Hf)
0.72
Holmium (Ho)
0.52
Indium (In)
0.91
Iridium (Ir)
0.95
Lanthanum (La)
9.23
Lead (Pb)
8.19
Lithium (Li)
19.09
Lutetium (Lu)
0.133
Manganese (Mn)
21.29
Mercury (Hg)
0.19
Molybdenum (Mo)
2.37
Neodymium (Nd)
8.65
Nickel (Ni)
13.99
Niobium (Nb)
3.21
Praseodymium (Pr)
3.11
Rhenium (Re)
0.57
Rubidium (Rb)
23.62
Samarium (Sm)
1.52
Scandium (Sc)
3.71
Selenium (Se)
4.2
Silver (Ag)
0.058
Strontium (Sr)
91.68
Tantalum (Ta)
0.195
Tellurium (Te)
0.083
Terbium (Tb)
0.261
Thallium (Tl)
1.194
Thorium (Th)
3.02
Thulium (Tm)
0.283
Tin (Sn)
2.2
Tungsten (W)
0.79
Uranium (U)
1.59
Vanadium (V)
24.36
Ytterbium (Yb)
0.8
Yttrium (Y)
7.53
Zinc (Zn)
14.97
Zirconium (Zr)
24.32
To determine emissions of these elements just follow the example above with the Thorium and Uranium and factor from those tons.
What layer of the sun does nuclear fusion occur?
It has to be at hundreds of millions of degrees kelvin, before a fusion reaction between deuterium and tritium will start
Is a hydrogen bomb the same as nuclear fusion?
Yes and no:
- nuclear fusion makes hydrogen bombs possible
- an actual hydrogen bomb is a rather complex device, involving both nuclear fission and nuclear fusion triggering each other in a precisely timed sequence. Most hydrogen bombs derive 90% of their yield from nuclear fission, almost all of this is from fission of uranium-238 in the tamper around the last fusion stage caused by high energy (15 MeV) fusion neutrons.
Hydrogen bombs operate on a fission-fusion-fission sequence. The full process of a typical modern hydrogen bomb goes something like this:
- The X-Unit (master timing controller) fires 32 detonators on the explosive lenses of the fission primary stage.
- The explosive lenses create an implosion shock wave which crushes the hollow tritium gas filled sealed pit made of plutonium to about 1/3 its normal size (about 27 times its normal density and very supercritical).
- The X-Unit fires the electrical neutron source (a miniature particle accelerator accelerating tritium ions). The fusionof these tritium ions fires neutrons through the supercritical plutonium core.
- Fission begins in the primary stage core.
- When the compressed tritium gas in the sealed pit inside the primary core is heated enough by fission, fusion begins in the center of the primary stage core.
- Neutrons from the tritium fusion in the center of the primary core "boosts" the fission of the plutonium of the primary core.
- X-rays from the primary stage travel through the radiation channel from the primary stage to the cylindrical secondary stage and down its length.
- The x-rays cause a radiation implosion of the secondary stage, compressing it rapidly to very high density.
- Neutrons from the primary stage travel to the "sparkplug", a rod of plutonium in the center of the secondary stage and running its length, which by this time the radiation implosion has compressed to supercriticality.
- The "sparkplug" fissions, emitting neutrons into the lithium deuteride layer of the secondary around the "sparkplug". The lithium captures these neutrons and produces tritium, resulting in a deuterium tritium fusion fuel mix.
- The "sparkplug" continues fissioning, pushing out against the radiation implosion. This combined inward and outward pressure compresses and heats the deuterium tritium fusion fuel mix until fusion begins in the secondary stage.
- High energy (15 MeV) neutrons from the secondary stage fusion cause fission in the uranium-238 tamper surrounding the secondary.
How many fissions and fusions was that now?
What percentage of the world's electricity is supplied by nuclear fusion reactors?
I will give you 2 answers. First and most correctly, 0%. We have not found a way to initiate and control fusion energy in a way that is economically viable. The control part is key. An example of an uncontrolled nuclear fusion reation is the Hydrogen Bomb. Second the smart ass answr, since the sun supplies most of the energy to the earth, which plants used and had become oil, most of our energy comes from nuclear fusion. The first answer is correct though. Also it may be possible that you are mistaking nuclear fusion for fission, which delivers 11% of the world's energy needs
Is nuclear energy produced by fusion?
Absolutely, mostly as 15 MeV neutrons. This causes neutron activated secondary radioactivity in surrounding material. On decommissioning a fusion reactor (assuming we ever figure out how to build one) this part of the reactor would have to be handled as radioactive waste, just as the non-fuel assemblies of a fission reactor must be treated now. There is also alpha radiation, but the biggest problem here is weakening and flaking of a thin layer of reactor vessel wall due to helium bubble accumulation.
Compare and contrast nuclear fission and nuclear fusion?
The process of combining two nuclei to form a heavier nucleus and thereby releasing energy is nuclear fusion. When a neutron strikes an atom of uranium-235, the atom captures the neutron, becoming an atom of uranium-236 with an excited nucleus. The U-236 nucleus vibrates rapidly and cannot hold itself together; it splits into several pieces (smaller atoms, free neutrons, etc.) in a process called nuclear fission (fission means "division"), releasing an enormous amount of heat energy and gamma rays.
What is nuclear fusion on the sun and where does it occur?
nuclear fusion is when 2 hydryon atoms combine or FUSE together. when this happens the neculous combine therefore causing nuclear fussion which releaces masses of heat and light enegry that radiates to earth
What are the products of nuclear fission and fusion?
The nuclear fission and/or fusion results in loss of mass (or mass defect) that transforms into energy according to formula E = mc2 (c is light velocity). The resulting energy manifests itself as heat energy that produces steam. The steam spins the turbines that spins electric generators and hence producing electricity.
Are nuclear reactions and nuclear fusions the same thing?
No, nuclear reactions refer to any processes involving changes in the nucleus of an atom, which includes both nuclear fission and fusion. Nuclear fusion specifically refers to the process where two atomic nuclei combine to form a heavier nucleus, releasing a large amount of energy.
How does the nuclear fusion creates new elements inside stars?
Small nuclei combine to form larger nuclei
Where has nuclear fusion been used?
Nuclear fusion has been primarily used in research facilities and laboratories to study its potential for generating energy. It has not yet been harnessed for practical energy production on a commercial scale, although there are ongoing efforts to develop fusion reactors for this purpose.
How is nuclear energy is generated during nuclear fusion?
Nuclear fusion involves the joining together of two atomic nuclei, fusing them into a single nucleus. When you join two nuclei together (usually light nuclei with only a few protons and/or neutrons), a tremendous amount of energy is released. Just as it takes a tremendous amount of energy to pull apart the pieces of a nucleus, when you put two pieces together, a lot of energy is released.
Fusion is often confused with nuclear fission, but they are very different. Fission involves the breaking apart of a single nucleus into two smaller nuclei.
Fusion is joining nuclei. Fission is breaking apart a nucleus.
A tremendous amount of energy is released upon joining two nuclei together (it is this reaction that is happening inside the sun). It also takes a huge amount of energy to get this reaction to occur. The only way we currently know how to start a nuclear fusion reaction efficiently is to use an atomic bomb to get it started! This is how much energy you need to start the reaction! There are several other ways that we know of to start fusion reactions, but they all require more energy input than you get as energy output.
There is a tremendous amount of research currently on so-called "cold fusion" or a way to do fusion without this huge amount of energy input. Currently all known methods involve putting in MORE energy than you get out! That's not a good design for a power plant, to say the least (nor is having atomic bombs going off inside to keep the reactors going!).
Where in the sun do most of the nuclear reactions occur?
At the center, where the gravitational pressure is highest.
Do fusion reactions provide nuclear power?
No, a fission reaction is not necessary to trigger a fusion reaction, but for us on earth, it is. In the field of nuclear weapons, a fission bomb is needed to create the heat necessary to set off a fusion weapon. We have to use fission, or, rather, the energy created by that, to initiate the fusion reaction. It might be possible to use a high power source, like a laser, on a small amount of material to get fusion to occur. But we are still experimenting with this in the Tokamak, and it's far from being a done deal. Stars are, in general, massive nuclear fusion reactors. Their constant consumption of fuel powering their high rate of fusion creates a massive amount of energy, and the stars' huge gravity keeps this process from blowing the whole thing apart. No fission is needed to sustain this reaction.
Nuclear fusion compared to nuclear fission?
Nuclear fusion is the process of combining two light atomic nuclei to form a heavier nucleus, releasing large amounts of energy. Nuclear fission is the process of splitting a heavy atomic nucleus into smaller nuclei, also releasing energy. Fusion powers the sun and hydrogen bombs, while fission is used in nuclear power plants and atomic bombs. Fusion reactions produce less radioactive waste than fission reactions.
What process release the most energy from nuclear fusion burning or shrinking due to gravity?
In a star a balance exist between gravity shrinking and expansion due to fusion energy released.
At what temperature do star begin the process of nuclear fusion?
Stars begin the process of nuclear fusion when their cores reach temperatures of around 10 million degrees Celsius. At this temperature, hydrogen atoms in the core of the star are able to overcome the electrostatic repulsion between positively charged protons and fuse together to form helium.
