Nuclear power

[bommel]

Mainly stuff that has higher radiation or different forms of radiation.
You have three types of radiation: alpha, beta and gamma.
Alpha radiation might be stopped by a sheet of paper so it will also be stopped by your skin for example.
Beta radiation is stronger. It will be stopped by a thin aluminium plate.
Gamma radiation is really strong. That's where large amounts of lead are needed. And this is the most dangerous form because it might alter your cells (i. e. DNA etc) and that's what causes radiation diseases. Tough the other two forms can be dangerous, too.

[guest6785]

so,is that how most people get cancer?

[bommel]

so,is that how most people get cancer?

No, no! If you don't work or live near a radioactive contamained area you are just exposed to harmless radiation, for example C14. That's a radioactive carbon isotope. Scientists use this for dating organic things for example. This works because while you are alive you absorb "fresh" C14 so the concentration stays approx. the same. But if you die you won't absorb any fresh C14 and it starts to break down. As we now the half-life of C14 we could make relatively good estimations on the age of the organic material. This is also knwon as radiocarbon dating.

[Payä Tìrol]

Most people aren't aware of this, but you are continually exposed to a low-level background radiation pretty much everywhere on Earth. Sources include cosmic radiation, medical radiology, radioactive minerals and elements, and human made sources.

For most people, background radiation is harmless. Your body has mechanisms in place that proofread and repair, to put it simply, your DNA. These mechanisms aren't perfect, however, and cancer is usually the result of mutations that passed through proofreading, accumulated over a lifetime. The problem is when someone takes a single large dose of radiation, or lives with a elevated daily dose of radiation. When you overwhelm the repair mechanism in your cells, the mutations start accumulating much more quickly than normal, and you're suddenly at a much higher risk for cancer down the line.

[Toruk Makto]

Ionizing radiation can come from electromagnetic sources as well. Equally unhealthy in large doses.

[bommel]

Ionizing radiation can come from electromagnetic sources as well. Equally unhealthy in large doses.

True, imagine the old CRT displays (I mean the really old ones)...

[Payä Tìrol]

Even exposure to UV light, considerably weaker than gamma radiation, is enough to cause adjacent Thymidine (T) bases in DNA to undergo covalent linking. This causes a mutation if not repaired before the next synthesis cycle.

[Ku'rända]

Let's point this out so nobody stupid misunderstands things.. :B

Radiation =/= Radioactive

[bommel]

Let's point this out so nobody stupid misunderstands things.. :B

Radiation =/= Radioactive

Good point (though I'm not sure if I let it look like this)

[Ku'rända]

Let's point this out so nobody stupid misunderstands things.. :B

Radiation =/= Radioactive

Good point (though I'm not sure if I let it look like this)

Naw, it's just that when folks talk about radioactivity, people generally consider radiation (which is a part of it!) to be the same thing.

Radioactive=Radiation
Radiation=/=Radioativity

Sort of how "All Blackbirds are Black birds, but not all Black Birds are Blackbirds"

[bommel]

Naw, it's just that when folks talk about radioactivity, people generally consider radiation (which is a part of it!) to be the same thing.

Radioactive=Radiation
Radiation=/=Radioativity

Sort of how "All Blackbirds are Black birds, but not all Black Birds are Blackbirds"

I remember a story of my former physics teacher at school:
In one of his earlier years he had a small amount of caesium(?) and a Geiger counter to show his students the radiation. All students moved back to the last row while there was a very low amount of crackling noise. Then he switched the TV on (~70's CRT TV set) and the Geiger counter went like *booooom*. His pupils were so scared

[Ku'rända]

I remember a story of my former physics teacher at school:
In one of his earlier years he had a small amount of caesium(?) and a Geiger counter to show his students the radiation. All students moved back to the last row while there was a very low amount of crackling noise. Then he switched the TV on (~70's CRT TV set) and the Geiger counter went like *booooom*. His pupils were so scared

Should have got him to drop the cesium in to a bucket of water :B  That would scare 'em good

[bommel]

Should have got him to drop the cesium in to a bucket of water :B  That would scare 'em good

Yeas ^^
However, we had done this little experiment with sodium in my chemistry class at school

[Jameso]

It s good fusion power and it leaves no substances that will harm environment!

[Kerame Pxel Nume]

It s good fusion power and it leaves no substances that will harm environment!

I just wonder: Why should we build and maintain complicated fusion reactors, if nature equipped us with one, that's working within parameters for 4 billion years? All it takes is harvesting the 1.4kW/m² we recieve here. The technology exists (CSP), yields a net efficiency of 40% and unlike reactors of any kind can quickly follow the power grid's consumption demands. To regulate a nuclear reactor (be it fission or fusion) one must slowly adjust the parameters to keep the reaction stable. In a CSP power plant you just turn a few mirrors toward or away from the sun.

[Payä Tìrol]

The main issue with solar is the complete inability to power anything during the night. Another is, with our current power transmission grid, you'll lose a very significant amount of that energy bringing it from a location with consistent sunlight, such as the planned locations in Arizona and other desert locations, to most major metropolitan areas.
Please keep in mind that I'm not saying there isn't room for a great deal of improvement. The percentage of our electricity in the States coming from renewables is still low compared to, say, Germany, and recent government initiatives and incentives to defray the cost of solar for the average consumer is definitely helping, if for no other reason than to put economies of scale into effect, in order to decrease the cost and increase the quality of solar technology
Unfortunately, we will be unable to completely rely on renewable power until we can make major advances in energy storage and transmission, but that's no reason why we can't use it to cover a large majority of the extra energy usage that typically happens during the day, compared to during the night.

[Jameso]

I saw on discovery that they are building artificial leafs.
Wich will collect the energy from sun.

[Kerame Pxel Nume]

The main issue with solar is the complete inability to power anything during the night.

In the last years there was tremendous progress in that field. And a some people had really clever ideas. For example one can use molten salt to store heat and power the turbines from that in the night.

Another one is, to transmit steam instead of electricity, according to calculations, at a power of about 0.1GW a steam transmission over 1500km would work at 80% efficiency. The cool thing is, that the steam pressure in the transmission lines would also act as a energy store.

Another is, with our current power transmission grid, you'll lose a very significant amount of that energy bringing it from a location with consistent sunlight, such as the planned locations in Arizona and other desert locations, to most major metropolitan areas.

Especially the US really have to mock up their energy grid. It's falling apart more and more. If the US invested into a nationwide high voltage DC grid, all the current problems (blackouts due to power imbalances) would go away, plus it would open up the possibility for Desertec-US

Please keep in mind that I'm not saying there isn't room for a great deal of improvement. The percentage of our electricity in the States coming from renewables is still low compared to, say, Germany, and recent government initiatives and incentives to defray the cost of solar for the average consumer is definitely helping, if for no other reason than to put economies of scale into effect, in order to decrease the cost and increase the quality of solar technology

The one thing is photovoltaics. IMHO good for isolated areas where no transmission line will ever go. But for large scale power production I prefer CSP. Which is proven and current developments focus on further increasing efficiency. But what the current state of technology lacks in efficiency can be compensated by collecting more light.

Unfortunately, we will be unable to completely rely on renewable power until we can make major advances in energy storage and transmission, but that's no reason why we can't use it to cover a large majority of the extra energy usage that typically happens during the day, compared to during the night.

Transmission is no longer the problem. Here in Europe a number of HVDC lines have been installed, mostly for energy exchange between Scandinavia and Continental. Heck we're "crazy" enough to put a whole HVDC transformer station into a container on the open sea (worst environment you can think of), to transmit power from the off-shore windpark installed there to the mainland at lowest possible losses.

All this stuff works, and so far it scales well: The voltages for HVDC are reached, it just will take more current. And the nice thing about DC is, that you can simply connect DC sources in parallel.

[Payä Tìrol]

I'm sure the attitude is completely different in Europe, but there's just so much red tape and public opinion to go through to get -anything- like that done in the States.

For example, where I live in MA, there's been a debate going on for the last half decade to construct a pretty modest wind farm 35km offshore, to help power households on Cape Cod. It's been 4 years and absolutely nothing has been done yet except back and forth lawsuits and injunctions from people claiming that it will spoil their view of the Atlantic (I'm pretty sure it'll be barely visible past the horizon).

My point was: While it's nice to say "well, efficiency isn't great but we can just cover it by building more", that sort of thing just doesn't fly here
States in the West can pass these sort of things more easily, I suppose, as a much, much greater portion of the land in the west is uninhabited and federally owned anyway. People tend to want these things... Just not in their "backyard". It's depressing that it often takes a major catastrophe to get the country to change anything.

Also, I'm not much of a physics person, I'm pretty sure I'm missing the implications of a lot of what you said
(Especially the part on HVDC... I was under the impression that doing anything long distance in DC basically kills your efficiency)
I did, however, read an article about how China was revamping their entire HV power grid to be double the voltage of what it was before, in order to decrease loss from resistance, and I think one of the main concerns was that it would increase the vulnerability of the grid to damage from solar radiation.

[Kerame Pxel Nume]

That AC was/is used in power grids from the 20th century comes from the fact, that transforming voltage can be done by relatively simple transformers: Solenoids on a common core with their winding ratio determining the voltage ratio.

The higher the voltage, the lower the losses due to ohmic resistance. But that's not the whole story:
As long as the voltage is low enough, AC is efficient, because transforming is easy. For long distance you want to yank up the voltage up to several 100kV, and then another effect kicks in: Polarization of the material surrounding the conductor (being it air, ceramics, or any other insulator). With every voltage swing the polarization is inverted, and with every change of polarization energy is dissipated in form of heat. Also with very long distances the transmission lines become antennas radiating away the energy.

To overcome this, you want to reduce the frequency to 0, i.e. DC. However DC used to be difficult next to impossible to transform from/to high voltages using old-style electrics. But due to modern solid state electronics this is no longer the case. Solenoid transformers are replaced by switching voltage convertors and charge pumps. With the nice side effect, that those are also more efficient, than solenoid transformers.

With only DC on the line all the power dissipating effects of AC vanish and you end up with good old Ohm, which can be overcome by high voltage.