There may be a confusion between energy density and power density.
I read that the thermal energy density is around 2 x 10^16 J/m^3 while it is the power density which has a low figure, probably close to 30 W/m^3.
Researching further, I find that if you divide the thermal energy density by the power density, you get a time of around ~20 million years. This is known as the Kelvin-Helmholtz timescale. It would be the lifetime of the Sun if it were powered by its own gravitational contraction rather than nuclear fusion.
The E=MC^2 energy at the centre of the sun is immense since the density is about 150g/cm^3 (c. 12x that of lead). But, the fusion process is remarkably slow so the power generated is low per unit volume (Galu's number of c. 30W per m^3).
There's a lot of the sun and its very dense in the middle, so the heat generated in the core is immense.
This from Physics stack exchange helps to put it in perspecive
"Protons collide all the time in the Sun's core, but there is no bound state of two protons because there aren't any neutrons to hold them together. Protons can only fuse if one of them undergoes beta plus decay to become a neutron at the moment of the collision. The neutron and the remaining proton fuse to form a deuterium nucleus, and this can react with another proton to form 3He. The beta plus decay is mediated by the weak force so it's relatively slow process anyway, and the probability of the beta plus decay happening at just the right time is extremely low, which is why proton fusion is relatively slow in the Sun. It takes gazillions of proton-proton collisions to form a single deuterium nucleus."
Here is the link Why does the Sun's (or other stars') nuclear reaction not use up all its "fuel" immediately? - Physics Stack Exchange
(Which begs the question from me, what kind of earth bound fusion process are scientists working on for energy production because the one in the sun doesn't look all that promising :confised: )
There's a lot of the sun and its very dense in the middle, so the heat generated in the core is immense.
This from Physics stack exchange helps to put it in perspecive
"Protons collide all the time in the Sun's core, but there is no bound state of two protons because there aren't any neutrons to hold them together. Protons can only fuse if one of them undergoes beta plus decay to become a neutron at the moment of the collision. The neutron and the remaining proton fuse to form a deuterium nucleus, and this can react with another proton to form 3He. The beta plus decay is mediated by the weak force so it's relatively slow process anyway, and the probability of the beta plus decay happening at just the right time is extremely low, which is why proton fusion is relatively slow in the Sun. It takes gazillions of proton-proton collisions to form a single deuterium nucleus."
Here is the link Why does the Sun's (or other stars') nuclear reaction not use up all its "fuel" immediately? - Physics Stack Exchange
(Which begs the question from me, what kind of earth bound fusion process are scientists working on for energy production because the one in the sun doesn't look all that promising :confised: )
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Tokamaks have been around since the 1960s and originally employed doughnut-shaped plasma rings.
The future appears to lie with a tokamak which employs a cored apple-shaped plasma ring that contains the plasma more efficiently.
This 'Spherical Tokamak' design achieves a much higher plasma pressure for a given strength of magnetic field containment which is now supplied by High Temperature Superconducting (HTS) magnets.
The objective remains the same - to fuse heavy isotopes of hydrogen, tritium and deuterium under extreme heat and pressure.
UK’s latest fusion reactor, MAST Upgrade, boots up | Science | Felix Online
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I found this interestng and explanatory article:
Fusion Energy Is Coming, and Maybe Sooner Than You Think
There's a long-running joke that fusion is the energy source of the future - and always will be. One thing's sure, I won't see commercial production of fusion power in my lifetime.
Tokamak. Fusion reactor.
Will it ever work ?
Articles mostly rehash the same stuff and forget a major issue: Plasma stability.
The magnetic confinement enables the plasma at a huge high temperatures to not touch the walls.
The trouble is, magnetodynamics is not fully understood, there are fluctuations which are random and of a chaotic behavior that can disrupt the thin confinement layer, punching through, making total disaster.
This is not presently well understood, all what is done, is to pray for this not to happen statistically. Another prayer is hoping the statistic will improve going at higher sizes, well over ITER which is pretty large.
I think they do not know where they go and it is a very long way when looking a the Q factor where Q=1 is the break even about energy. The best we have over decades of works is below 1. ITER goal is to obtain better than 1. We need Q=100 for industrial feasibility.
Will it ever work ?
Articles mostly rehash the same stuff and forget a major issue: Plasma stability.
The magnetic confinement enables the plasma at a huge high temperatures to not touch the walls.
The trouble is, magnetodynamics is not fully understood, there are fluctuations which are random and of a chaotic behavior that can disrupt the thin confinement layer, punching through, making total disaster.
This is not presently well understood, all what is done, is to pray for this not to happen statistically. Another prayer is hoping the statistic will improve going at higher sizes, well over ITER which is pretty large.
I think they do not know where they go and it is a very long way when looking a the Q factor where Q=1 is the break even about energy. The best we have over decades of works is below 1. ITER goal is to obtain better than 1. We need Q=100 for industrial feasibility.
Yes. Making fission safer and decommissioning cheaper and burning/recycling wastes.
About safety, do not forget Tchernobyl was under Soviet ruling, drunk bureaucrats. Fuckyoushima built too low at sea level, an amazing dumbness from people well aware of tsunamis at their seismic archipelago.
No doubt we can do much safer.
About safety, do not forget Tchernobyl was under Soviet ruling, drunk bureaucrats. Fuckyoushima built too low at sea level, an amazing dumbness from people well aware of tsunamis at their seismic archipelago.
No doubt we can do much safer.
Unless you have been living under a stone, you know we are currently facing huge price rises in Gas. Could be £700 a year for a typical home.
Now this might help some alternative sources of Energy. But recent calculations for PhotoVoltaic installations aren't as rosy as you might think:
Solar panels: are they worth it? - MoneySavingExpert
£4,800 to install a system on your roof. Measured as 4kWp, which is peak output on a sunny day. Savings are around £300 a year with some subsidies thrown in. Pays off in around 20-30 years, by which time it will be needing replacement IMO.
Energy companies only pay you about 1p for every kWh put back into the grid. And it doesn't work at night when you most likely need it. Even 4kWh isn't a lot. NIGHTMARE!
Now this might help some alternative sources of Energy. But recent calculations for PhotoVoltaic installations aren't as rosy as you might think:
Solar panels: are they worth it? - MoneySavingExpert
£4,800 to install a system on your roof. Measured as 4kWp, which is peak output on a sunny day. Savings are around £300 a year with some subsidies thrown in. Pays off in around 20-30 years, by which time it will be needing replacement IMO.
Energy companies only pay you about 1p for every kWh put back into the grid. And it doesn't work at night when you most likely need it. Even 4kWh isn't a lot. NIGHTMARE!
When Chernobyl blew up, it was in the course of performing a safety test. Various factors made it all go horribly wrong. One major one was a midnight shift change where tired workers handed over to the next shift without handing over properly or explaining to the next shift what was going on, all unaware there was already a serious overheating problem.
Most of Fukushima's problems was spillage and overheating of spent nuclear waste. Almost all historical Nuclear waste is still onsite at most power plants. Hot stuff!
Britain persists in building reactors at sea level. Sizewell B is an example. I have been watching the La Palma volcanic eruption with interest. The Canary Islands are due to largely slide into the Sea within the next 5,000 years. A similar event took place in Norway about 5,000 years ago and drowned the land bridge between Britain and the Continent. The bottom line on the canaries is we can expect a 10-20 foot Tsunami on the South Coast when it happens.
Most Nuclear scenarios predict a major catastrophe every 25 years even with safer reactor technology. Seems about right!
More cheering is this simple low-tech solution to overheated Indian houses. It's 46C there sometimes. Impossible to sleep.
Life at 50C: Keeping cool in India'''s heatwaves - BBC News
Not snake-oil. Paint the roof white! Reduces temperatures 3-4C.
Most of Fukushima's problems was spillage and overheating of spent nuclear waste. Almost all historical Nuclear waste is still onsite at most power plants. Hot stuff!
Britain persists in building reactors at sea level. Sizewell B is an example. I have been watching the La Palma volcanic eruption with interest. The Canary Islands are due to largely slide into the Sea within the next 5,000 years. A similar event took place in Norway about 5,000 years ago and drowned the land bridge between Britain and the Continent. The bottom line on the canaries is we can expect a 10-20 foot Tsunami on the South Coast when it happens.
Most Nuclear scenarios predict a major catastrophe every 25 years even with safer reactor technology. Seems about right!
More cheering is this simple low-tech solution to overheated Indian houses. It's 46C there sometimes. Impossible to sleep.
Life at 50C: Keeping cool in India'''s heatwaves - BBC News
Not snake-oil. Paint the roof white! Reduces temperatures 3-4C.
Chernobyl disaster is clearly from human errors under bureaucratic pressure and policies.
Fukushima, the disaster has been the consequences of human errors, not simply from the seism and tsunami. Cooling was known critical, the tsunami destroyed the emergency cooling system. Human errors on top of that from inadequate management from the very beginning.
Human errors and policies are the weak point about safety.
Fukushima, the disaster has been the consequences of human errors, not simply from the seism and tsunami. Cooling was known critical, the tsunami destroyed the emergency cooling system. Human errors on top of that from inadequate management from the very beginning.
Human errors and policies are the weak point about safety.
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After the Chernobyl disaster on 26 April 1986, a plume of radioactive material was carried more than 1,300 miles to the UK by the prevailing winds.
I remember my Geiger counter registering 36 counts/min - twice the normal background rate.
Because radioactive fallout landed on the upland pastures on which they grazed, sheep became radioactive.
Consequently, lamb had to be scanned by government officials before it was allowed to enter the food chain
The last restrictions on the movement and sale of sheep in the UK weren't lifted until 2012 - 26 years after the meltdown.
I remember my Geiger counter registering 36 counts/min - twice the normal background rate.
Because radioactive fallout landed on the upland pastures on which they grazed, sheep became radioactive.
Consequently, lamb had to be scanned by government officials before it was allowed to enter the food chain
The last restrictions on the movement and sale of sheep in the UK weren't lifted until 2012 - 26 years after the meltdown.
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