Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifested as either the release or the absorption of energy. This difference in mass arises due to the difference in atomic binding energy between the nuclei before and after the reaction. Fusion is the process that powers active or main sequence stars and other high-magnitude stars, where large amounts of energy are released.
A fusion process that produces nuclei lighter than iron-56 or nickel-62 will generally release energy. These elements have relatively small mass per nucleon and large binding energy per nucleon. Fusion of nuclei lighter than these releases energy (an exothermic process), while fusion of heavier nuclei results in energy retained by the product nucleons, and the resulting reaction is endothermic. The opposite is true for the reverse process, nuclear fission. This means that the lighter elements, such as hydrogen and helium, are in general more fusible; while the heavier elements, such as uranium, thorium and plutonium, are more fissionable. The extreme astrophysical event of a supernova can produce enough energy to fuse nuclei into elements heavier than iron.
In 1920, Arthur Eddington suggested hydrogen-helium fusion could be the primary source of stellar energy. Quantum tunneling was discovered by Friedrich Hund in 1929, and shortly afterwards Robert Atkinson and Fritz Houtermans used the measured masses of light elements to show that large amounts of energy could be released by fusing small nuclei. Building on the early experiments in artificial nuclear transmutation by Patrick Blackett, laboratory fusion of hydrogen isotopes was accomplished by Mark Oliphant in 1932. In the remainder of that decade, the theory of the main cycle of nuclear fusion in stars was worked out by Hans Bethe. Research into fusion for military purposes began in the early 1940s as part of the Manhattan Project. Self-sustaining nuclear fusion was first carried out on 1 November 1952, in the Ivy Mike hydrogen (thermonuclear) bomb test.
Research into developing controlled fusion inside fusion reactors has been ongoing since the 1940s, but the technology is still in its development phase.
Hi All,
I was wondering about some equations/formulae related to Fusion. How much energy/what temperature does it take to initiate Fusion? And how is this amount of energy affected by the different element/isotopes used, pressure, magnetic attraction and other variables?
Thanks in advanced.
I want to take a liquid metal, Aluminum at 700oC and pour it into a steel mold starting at 20oC. For the purpose of the question let’s say that the heat transfer is 100% with no losses to the surroundings.
Here are some numbers:
Al
Mass = 200 g = 0.2 Kg
Ti, Al = 700oC
Cp = 900 J/Kg-K...
Homework Statement
Consider the following fusion reaction
2H+3H →4He + n
in which deuterium and tritium fuse together to form a stable isotope of helium plus a neutron.
In all of physics, we see experimental confirmation of Conservation of Energy, in which the total
amount of energy in a closed...
Hello. I am currently a senior in high school. I am currently taking AP Physics C and will be through calc III/diff eq by the time i graduate. I am interested in going into nuclear engineering but i do not just want to work at some power plant the rest of my life. I am interested in theorhetical...
Calculate heat of fusion.?
find the heat of fusion of ice using the ffg. data obtained from an experiment:
wt. of brass calorimeter = 50 g
specific heat of brass calorimeter = 0.09 cal/g-°C
m of ice= 20.45 g at 0°C
TF= 20 °C
mH2O = 200 g at 30°C
I seem to be having a problem adding a reply to the end of the previous thread so I am starting a new one!
Thanks for everyone replying.
A couple of points. The first is that nobody seems to have tried two end-on plasmas directed at each other. A dense pair of plasmas fired at each other...
Homework Statement
The molar heat fusion and vaporization of benzene are 10.9kJ/mol and 31.0 kJ/mol, respectively. The melting temperature of benzene is 5.5C and it boils at 80.1C.
a) calculate the entropy changes for solid to liquid, and liquid to vapor of benzene
b) would you expect the...
As per a previous thread, if you fire two plasma jets of deuterium at each other at high enough relative velocity, the deuterons would collide and fuse into helium.
Does anyone know what is the relative velocity in kilometers per hour necessary for deuterons hitting each other head on to fuse...
[b]1. Calculate the minimum amount of NRG, in joules required to completely melt 130g of silver initially at 15 degrees Celsius.
[b]2. ? Q = mC (Tf-Ti) + mHf? saw it online somewhere, not sure what the proper formula for this problem is, and if it is done does everything need to be converted to...
I invite you to take a new look at http://focusfusion.org/"
After a long search for funding, Eric Lerner and his team from LPP are really on the move now, constructing a new, most powerful DPF (Dense Plasma Focus) machine, exclusively devoted to fusion research, that should deliver a...
Hello all,
I cam across this company on the web and was very suprised to see that a company is trying to market a different style of fusion reactor. I only knew of the tokamak geometry and of the large scale fusion reactor projects like ITER.
Ayone else see this...
Hello,
I am curious about fusion reaction cross sections, and fusion power in general, and have been trying to self-teach myself in this area. I saw some emprical data for cross section curves in a paper that I read recently, and thought I understood enough of what made the curve (cross...
I was reading this "almost-a-real-article" in Popular Mechanics and came across the following extract
http://www.popularmechanics.com/science/earth/4322757.html
Which, to my layman's ear, sounded absolutely fantastic until I read one of the comments
Now, it seems that...
Homework Statement
The sun is powered by fusion, with four protons fusing together to form a helium nucleus (two of the protons turn into neutrons) and, in the process, releasing a large amount of thermal energy. The process happens in several steps, not all at once. In one step, two protons...
Hey everyone,
I am not knowledgeable in the field of physics, so please excuse me if my question is obvious or poorly worded. I have found myself reading recently about various Nuclear Fusion research, and just now I came across an overview of fusion contained by lasers, specifically at the...
If elements like uranium and thorium in fact did form the same way helium and carbon-iron do, which is through fusion. would we be able to know? Is there a way to tell if those elements are forming through fusion in the cores of stars? Like would it be possible to analyze the light coming from...
Hello All
I've got two years left in my Physics undergrad degree at a university in Ontario, Canada. My ultimate career goal is to do research in fusion energy, and I've just started looking into what steps I should take to get there, starting with grad school. Naturally, I have some...
Fusion raction produces high energy neutrons which cause activation of the walls of the reactor. Why can't their energy be collected by, for example, a microwave beam?
I found this presentation on Fusion Propulsion here:
http://fti.neep.wisc.edu/presentations/jfs_jannaf_1205.pdf"
The Gas Dynamic Mirror seemed the most interesting and I got a lot of Google hits on it, but here are some guys working on actual proof of concept hardware...
More failure and disappointment for something that was so promising
Notice the last statement. So it doesn't have enough money because commodity prices have gone up so much, wouldn't scaling it back starve the project even more? We need real commitment people, it's starting to look more...
I'm a science fiction writer, currently I write a novel related to laser fusion. As I know in chemistry, catalysis is the process in which the rate of a chemical reaction is either increased or decreased by means of a chemical substance known as a catalyst.
Are there catalysts in the nuclear...
I came up with this during idle afternoon. Don't know if it's worth something but I wanted to discuss it with someone. Basically, outline of business part is given on the picture
Horizontal tori are basically tokamaks and vertical pipes are "fusion combustion chambers" where working fluid...
I have been researching about fusion power to understand how it operates during thermonuclear reactions. I do not understand how and how much deuterium and tritium are placed into the magnetic confinement (tokomak). I appreciate it, if anyone guides me about this.
Thank you
Equation Needed to Figure Resulting Kinetic Energy and Velocities from Fusion...
Homework Statement
Hey,
I am have the initial velocities and masses of nuclei involved in fusion, and am trying to figure out the resulting velocities and kinetic energies. Since this is an inelastic reaction...
Homework Statement
Were doing this lab that is related to finding the specific heat and heat of fusion of water. To put the lab simply we filled aluminum calorimeters with water that's around 35°C. After that we took a handful of ice and it into the calorimeter full of water and measured the...
I need someone who has been keeping an eye on the biological literature.
It is by now an established fact that the human chromosome 2 originated as a fusion of two chimpanzee chromosomes (and I'm not about to dispute that, this post is in no way an advocacy of intelligent design :))
There are...
Hi All
Just wondering why does deuterium fused with itself not make helium-4 - instead it makes a triton or a helion and a proton or a neutron. These products could then fuse with deuterium to make helium-4.
What stops deuterium from fusing straight into alpha particles? Is the kinetic...
Homework Statement
Determine the specific latent heat of fusion of ice given the amount of time it takes the ice to melt (150 seconds). Energy is supplied to the ice at 530 W. The sample is .25 kg.
Homework Equations
Q= ml
The Attempt at a Solution
(Time * 530W) = .25kg * L
150...
http://www.cbsnews.com/video/watch/?id=4955212n
So, what should one make of this?
I would love to hear what people here with physics know-how think about both the people and the experiments.
k
Homework Statement
One of the thermonuclear or fusion reactions that takes place inside a star such as our Sun is the production of helium-3 (3He, with two protons and one neutron) and a gamma ray (high-energy photon, denoted by the lowercase Greek letter gamma, ) in a collision between a...
Here is the link to the Navy publication where they claim "evidence" of LENR--fusion at low activation energy input.
http://www.newenergytimes.com/Library2/2008/2008BossTripleTracks.pdf
Edit: and see here news release of American Chemical Society presentation...
I know from reading that when the core from a massive star is transformed into iron through the process of nuclear fusion that the star collapses because the newly formed iron core does not put out any energy to support the weight of the star. My question is, why is iron like this when it is...
http://news.yahoo.com/s/afp/20090324/ts_alt_afp/usscienceenergynuclear
I guess we'll have to wait and see...
Looks like it is being presented at the spring ACS meeting right now.
Hi, I was wondering:
why in hydrogen fusion are neutrinos ejected?
why in fission does the neutron actually knock over neutrons out of atoms
the nucleon are held together in the nuceus by nuclear forces which over power electrostatic forces. But what actually generates these forces? Are...
So it seems real obvious to me at the moment that if quantum teleportation becomes common day, then one huge benefit is fusing two hydrogen nuclei by teleporting them at the same location, or very close to each other. Is this a correct assumption, or is this question completely lacking...
I did a lab experiment were we measured the latent heat of fusion of ice but I am not quite sure what that is. I read that latent heat of fusion is the energy(heat) it takes to change liquid to solid. Is that true? Why would it take heat to freeze something?
Homework Statement
The question is: a 6 pack of cola cans contains m grams of liquid. you want to put ice into a perfectly insulated box to cool it down from Ts to Tf. The ice initially has temp Ti. So (a)how much ice would you need as a minimum. (ignore presence of cans and final state of...
[b]1. I need to find the latent heat of fusion of ice. The problem scenario is that i have a cup and fill it 1/3 full with water. I then take a cube of ice and put it in the cup. then the cube of ice melts
mass of the cup=.24g
mass of the cup when filled 1/3 with water=71.16g
initial...
Would it be feasible theoretically to use a continuous endothermic fusion reaction as a high-energy heat sink?
Would such a process be capable of producing unstable isotopes for use in nuclear fission?
I ask this as a science fiction writer and I would dearly love input and even direction or...
I have long wondered if you could combine fusion reactors with fission reactors. After all fusion produces large numbers of neutrons which can drive fission reactions. Then I saw this:
http://www.physorg.com/news152284917.html
So will this work? Is a combination of PWR and these things...
Homework Statement
How much ice (in grams) would have to melt to lower the temperature of 351 ml of water from 24 deg C to 5 deg C? (Assume the density of water is 1.0g/ml .)
Homework Equations
q=mc(deltaT)
The Attempt at a Solution
m=351 g c=4.18J/g*C deltaT=19deg C...
Which nuclear process is more economically feasible--fusion or fission? I think it's fusion because it produces more energy than it takes, as compared to fission. Am I right?
even if sustained nuclear fusion via deuterium-tritium type reactions were possible, and the energy that is released exceeds the energy that is put in, and this energy is harnessed as a conventional water-steam generator, would such a design be commericially viable, based on the current cost of...
I just read an article in the most recent Popular Science about a company, General Fusion, claiming that they would have fusion reactors with net power in FIVE YEARS. Of course, this sent alarm bells off in my head, and I'm wondering if there is any legitimacy to what they're doing, or if...
Homework Statement
An ice tray containing 200 g of water at 25 degrees celecius is placed in the freezer. How much heat energy has to be removed to change the water into ice at -4 degrees celcius?
Homework Equations
Q= mc(Tf-Ti) + MLf + mc(Tf-Ti)
The Attempt at a Solution
I know...