Nuclear fusion, How would they contain it, How would they control it, how long will it take.?

Question

In science it said tridium (from lithium) some "D" material name from the ocean it said they would use reinfoced steel and line it with lead "to absorb radiation". They currently have a test site in Princton NJ. Nice place sure hope nothin explodes.

Answer 1

Tritium is an isotope of Hydrogen
Contain Fusion with Gravity
Control Fusion with Feeding reaction
Use the sun as your guide
Princeton has been experimenting with Fusion since the '60s

Answer 2

Fusion reactions can only be contained by "magnetic bottles" because any known material would vaporize from the intense heat that is generated. This has already been accomplished with "tokamaks" (a Russian term), when a tiny amount of material was compressed enough to initiate fusion by an array of high-energy lasers arranged in a sphere around the sample.

The experiment lasted only a fraction of a second, and the energy produced was far less than the energy that went into it - so far.

One thing we don't need to worry about is a meltdown, as is possible with present-day fission reactors. If a fusion system fails, the reactions will stop instantly. And as far as I know, fusion reactions of the type being considered for energy production produce very little or no radioactivity.

Imagine spending what we do in Iraq being turned to fusion research instead...

Answer 3

Everyone is so hostile to say that the asker isn't making sense!

Tritium does come from lithium, Lithium-6 to be precise. When bombarded with a neutron, Lithium-6 will produce tritium.

The D material is deuterium, and is present in a ratio of about 1 atom Deuterium to 5000 atoms hydrogen in sea water.

The radiation that you are talking about is something called bremstrahhlung radiation and occurs when a charged particle has acceleration. (Going in a circle counts as acceleration towards the center). This radiation is prompt, meaning that it does not remain for long.

Fusion experiments and reactors won't explode from anything fusion. However, deuterium and tritium both behave like hydrogen. If you light up hydrogen, boom. If you light deuterium, boom. NJ is safe.

Answer 4

Your information has gotten quite garbled. Nuclear fusion is the joining of light atomic nuclei to make a heavier one. For example, four protons, of mass 1.008 each, if merged to make a helium nucleus of mass 4.003, would release 0.029 atomic mass units of energy. (This is how the sun works.) Because of the positive charges, the nuclei must be at extremely high temperatures in order to collide with enough vigor for fusion to occur. These temperatures (on the order of hundreds of millions of degrees) cannot be easily created, nor contained in anything other than suitable magnetic fields; any material substance would be instantly vaporized. Commercial production, if ever achieved, will probably use deuterium rather than hydrogen; it can be isolated from seawater at an acceptable cost. Tritium (which can be made from lithium in a nuclear reactor) may be used to initially ignite a reaction, but it is far too costly to be used as a fuel for continuing operation.

Answer 5

No .. it's tritium which is an isotope of hydrogem not lithium. Modern containment methods use magnetic fields.

Answer 6

Nuclear Fusion is the process powering the Sun and stars. In the core of the Sun, at temperatures of 10-15 million Kelvin, Hydrogen is converted to Helium by fusion - providing enough energy to keep the Sun burning - and to sustain life on Earth.

A vigorous world-wide research programme is underway, aimed at harnessing fusion energy to produce electricity on Earth. If successful, this will offer a viable alternative energy supply within the next 30-40 years - with significant environmental, supply and safety advantages over present energy sources


Nuclear energy can also be released by fusion of two light elements (elements with low atomic numbers). The power that fuels the sun and the stars is nuclear fusion. In a hydrogen bomb, two isotopes of hydrogen, deuterium and tritium are fused to form a nucleus of helium and a neutron. This fusion releases 17.6 MeV of energy. Unlike nuclear fission, there is no limit on the amount of the fusion that can occur.

To harness fusion on Earth, different, more efficient fusion reactions than those at work in the Sun are chosen - those between the two heavy forms of Hydrogen : Deuterium (D) and Tritium (T). All forms of Hydrogen contain one proton and one electron. Protium, the common form of Hydrogen has no neutrons, Deuterium has one neutron, and Tritium has two. If forced together, the Deuterium and Tritium nuclei fuse and then break apart to form a helium nucleus (two protons and two neutrons) and an uncharged neutron. The excess energy from the fusion reaction (released because the products of the reaction are bound together in a more stable way than the reactants) is mostly contained in the free neutron.

Fusion occurs at a sufficient rate only at very high energies (temperatures) - on earth, temperatures greater than 100 million Kelvin are required. At these extreme temperatures, the Deuterium - Tritium (D-T) gas mixture becomes a plasma (a hot, electrically charged gas). In a plasma, the atoms become separated - electrons have been stripped from the atomic nuclei (called the "ions"). For the positively charged ions to fuse, their temperature (or energy) must be sufficient to overcome their natural charge repulsion.

In order to harness fusion energy, scientists and engineers are learning how to control very high temperature plasmas. The use of much lower temperature plasmas are now widely used in industry, especially for semi-conductor manufacture. However, the control of high temperature fusion plasmas presents several major science and engineering challenges - how to heat a plasma to in excess of 100 million Kelvin and how to confine such a plasma, sustaining it so that the fusion reaction can become established.

The energy released in most nuclear reactions is much larger than that for chemical reactions, because the binding energy that holds a nucleus together is far greater than the energy that holds electrons to a nucleus.
Fusion occurs at a sufficient rate only at very high energies (temperatures) - on earth, temperatures greater than 100 million Kelvin are required. At these extreme temperatures, the Deuterium - Tritium (D-T) gas mixture becomes a plasma (a hot, electrically charged gas). In a plasma, the atoms become separated - electrons have been stripped from the atomic nuclei (called the "ions"). For the positively charged ions to fuse, their temperature (or energy) must be sufficient to overcome their natural charge repulsion.

Nuclear Fusion Basics 2
Conditions for a Fusion Reaction

JET Pulse #64159 - View of a plasma from the KL1 CCD video camera (from behind a quartz window). Movie
Three parameters (plasma temperature, density and confinement time) need to be simultaneously achieved for sustained fusion to occur in a plasma. The product of these is called the fusion (or triple) product and, for D-T fusion to occur, this product has to exceed a certain quantity - derived from the so-called Lawson Criterion after British scientist John Lawson who formulated it in 1955.

Attaining conditions to satisfy the Lawson criterion ensures the plasma exceeds Breakeven - the point where the fusion power out exceeds the power required to heat and sustain the plasma.

Temperature
Fusion reactions occur at a sufficient rate only at very high temperatures - when the positively charged plasma ions can overcome their natural repulsive forces. Typically, in JET, over 100 million Kelvin is needed for the Deuterium-Tritium reaction to occur - other fusion reactions (e.g. D-D, D-He3) require even higher temperatures.

Density
The density of fuel ions (the number per cubic metre) must be sufficiently large for fusion reactions to take place at the required rate. The fusion power generated is reduced if the fuel is diluted by impurity atoms or by the accumulation of Helium ions from the fusion reaction itself. As fuel ions are burnt in the fusion process they must be replaced by new fuel and the Helium products (the "ash") must be removed.

Energy Confinement
The Energy Confinement Time is a measure of how long the energy in the plasma is retained before being lost. It is officially defined as the ratio of the thermal energy contained in the plasma and the power input required to maintain these conditions. At JET we use magnetic fields (see Section 3) to isolate the very hot plasmas from the relatively cold vessel walls in order to retain the energy for as long as possible. Losses in a magnetically-confined plasma are mainly due to radiation. The confinement time increases dramatically with plasma size (large volumes retain heat much better than small volumes)- the ultimate example being the Sun whose energy confinement time is massive.

For sustained fusion to occur, the following plasma conditions need to be maintained (simultaneously).
* Plasma temperature: (T) 100-200 million Kelvin
* Energy Confinement Time: (t) 4-6 seconds
* Central Density in Plasma: (n) 1-2 x 1020 particles m-3 (approx. 1/1000 gram m-3, i.e. one millionth of the density of air). Note that at higher plasma densities the required confinement time will be shorter but it is very challenging to achieve higher plasma densities in realistic magnetic fields.

Answer 7

http://en.wikipedia.org/wiki/Tokamak