Nuclear fusion energy

  • Thread starter Xforce
  • Start date
18
4
we know nuclear fusion is a powerful,reliable and long lasting energy source,the power of future. 1 kilogram of fuel used in D-T fusion can generate as much as 3.401×10^14 joules of power, enough to power my home for a century. So how feasible is it to construct a small tokamak in my house with a size of a pot? The heating part can use microwave, the superconductive magnets can be replaced by neodymium magnets so I can get rid of the cryostats. The heat transfer and turbine thing can be replaced gamma radiation-electricity converting panels. Hi, everyone, shall I start building a tokamak in my garage?
 

russ_watters

Mentor
18,503
4,717
we know nuclear fusion is a powerful,reliable and long lasting energy source,the power of future. 1 kilogram of fuel used in D-T fusion can generate as much as 3.401×10^14 joules of power, enough to power my home for a century. So how feasible is it to construct a small tokamak in my house with a size of a pot? The heating part can use microwave, the superconductive magnets can be replaced by neodymium magnets so I can get rid of the cryostats. The heat transfer and turbine thing can be replaced gamma radiation-electricity converting panels. Hi, everyone, shall I start building a tokamak in my garage?
Welcome to PF.

I have to ask; are you being serious? They call fusion "the power of the future" because it hasn't been invented yet. So the short answer to your question is no.
 
18
4
Actually I am not planning to build one, but I am planning to design one.
 

berkeman

Mentor
54,889
5,134
Welcome to the PF. :smile:
So how feasible is it to construct a small tokamak in my house with a size of a pot?
As discussed in other fusion threads on the PF, the smaller the device gets, the less efficient it is (at least with current design paradigms). A Tokamak reactor gets more efficient and more practical as it gets larger, hence the very large sizes of the latest experimental reactors like ITER:

https://www.iter.org/
Actually I am not planning to build one, but I am planning to design one.
Good for you. You will need to continue learning physics, with a concentration on plasma physics. Once you are able to understand Chen, you will be in a good place to join a research team:

https://www.amazon.com/dp/3319223089/?tag=pfamazon01-20

upload_2019-3-13_7-40-53.png
 

Attachments

18
4
I like this book!And I often get up to www.iter.org/ to check out the structure of a fusion reactor. But I am considering of the “the larger the better” because huge reactors such as ITER have no mobility and low energy density. Certainly you can’t put it on a spaceship or something. However this might be caused by heat transfer of the reaction chamber.

Current designed fusion power plants such as the DEMO, something even larger than ITER and generates 2 gigawatts of power, all of them use the heat on the wall of reaction chamber to boil water and power a bulky turbine. This makes no sense! All D-T fusion release a photon with a energy of 17.8Mev, and that photon needs to hit and heat the reaction chamber then boil the water and power the turbine, then us the torque to power spinning magnets and generate power. The huge energy loss makes reactors seems not as powerful as 9 million times the power of coal, there are even more if we consider the neutron radiation.

However the reaction only release gamma ray photons with a certain energy level, this is extremely convenient for light-electric covertion and should be able to boost its efficiency to more than 50%, same or even better than the “spectrum-dividing” solar panels! If this technology is available, maybe commercial fusion energy is possible in a decade or two.
 

Attachments

Last edited by a moderator:

anorlunda

Mentor
Insights Author
Gold Member
6,521
3,587
However the reaction only release gamma ray photons with a certain energy level, this is extremely convenient for light-electric covertion and should be able to boost its efficiency to more than 50%, same or even better than the “spectrum-dividing” solar panels!
If you did achieve that, and if the other 50% went into heat, wouldn't it melt the structure in a short time?

If the other 50% pass through the structure and don't make heat, then won't the gamma rays kill the astronauts?
 
Ah Xforce . . you really need to learn the basics about nuclear fusion and understand the difficulties which have led to extremely large experimental machines. If you're serious, I'd recommend a graduate degree in Nuclear Engineering specializing in Fusion. I have done this, long ago, so here you go:

DT fusion releases most of its energy in the form of a high energy neutron (14.1MeV), and the rest (17.6-14.1) as a high speed alpha (4He) particle. There are no photons involved. Temperatures involved are in the 20 to 100 Million K range...

You cannot have any success doing anything 'nuclear' at home, no matter how much you 'wish it to be otherwise'.

A small fusion reactor currently only exists in the realm of sci-fi and movies (Mr. Fusion from 'Back to the Future'). The smallest fusion device made is relatively compact, but impossible to make into a power reactor. This is called a Hydrogen Bomb...
 
Last edited:
18
4
Yeah I need to learn more, because I am only a year 9 student interested in fusion technology and hates fossil fuel. Maybe I will get a graduate degree in nuclear engineering specializing in fusion in the future...
 
666
185
IIRC, you face a 'square vs cube' issue on your 'Mr Fusion' system. Until you can constrain plasma at sufficient density and for long enough, it just won't break even. Even the magnets are currently beyond home construction...

'Science Fair' neutron sources are a different approach, the equivalent of a Wimhurst machine to a turbo-generator...

( I remember the early '∞' Stellerators: There were such hopes... )

More recently, 'Polywell', 'muon catalysed' etc looked promising, and a viable design may yet come 'out of left field' but, IMHO, very unlikely...
 
Not to mention, that if a 'Mr. Fusion' were possible with DT or DD fusion, anyone near by would be exposed to a lethal dose of neutrons...

There is also 'aneutronic' fusion, but that takes about a Billion degrees K : https://en.wikipedia.org/wiki/Aneutronic_fusion

These guys are doing good work on it: https://lppfusion.com/

IMHO any reports of any version of 'cold fusion' are completely bogus, except muon catalysed fusion, which they've shown cannot reach break-even due to short muon lifetimes.

Read up on NIF as well, another path being pursued: https://lasers.llnl.gov/about/what-is-nif
 
Last edited:

Want to reply to this thread?

"Nuclear fusion energy" You must log in or register to reply here.

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top