deGrasse Tyson & Nye on Climate Change

[SeeGeeWhy]

Originally Posted by nik-

Additionally, Canada, especially on the relatively seismically stable Canadian shield, should be leading in nuclear energy.

Can we look at Breeder reactors or IFRs?

The impetus to build breeders isn't all that high now that we understand uranium reserves aren't as low as they once were thought to be. That and I really don't think we need reactors that produce weaponizable isotopes. We are past that. My preference is for burners that can consume existing waste and weapons stockpiles along with any "-ium" fertile fuel isotopes. My opinion, of course.

IFRs still have a significant meltdown risk despite what guys like Charles Till claim. 2/3 of the IFRs built in the US had partial meltdowns. Suriving a power outage is nice, but one single flow blockage and the thing melts. Another reason I love the MSR - liquid fuel means zero meltdown risk. Heck, that's the secret to how they consume so much of the available fuel and leave such little waste behind.

[troutman]

Does radioactive waste have to be stored on the planet? Is it too dangerous/expensive to launch it into space?

http://www.popsci.com/technology/art...lear-waste-sun

http://enenews.com/space-disposal-fo...ama-commission

[SeeGeeWhy]

Originally Posted by Erick Estrada

Is nuclear energy really a long term solution? The radioactive waste still gets stored on earth and it lasts thousands of years. I realize that the CO2 mass emissions far surpasses what the equivalent radioactive waste would be but annually storing tonnes of radioactive waste on the planet will one day likely result in severe consequences.

With traditional Water Reactors, yes.. this is correct.

The problem is in 1% of the waste - the transuranics. These are the elements that are heavier than Uranium ... Am, Cm, Np. These elements are the reason long term, deep geological storage facilities are proposed. They have half lives that can be in excess of hundreds of thousands of years.

We have to put them away because Light water reactors can't burn them up as fuel because of the way the fuel assembly is designed. The fuel rods have solid pellets of enriched uranium pressed together. Completely randomly, you'll have some of the atoms fission into these transuranics, and they create hot spots which increase the risk of melting, so you've got to switch the rods out, process the pellets, etc.

There are alternative designs which avoid the issue of long term storage. Again, a single fluid MSR allows all of the isotopes to float in a homogeneous mixture, so these transuranics actually get burned as fuel instead of having to be left behind as waste.

The waste footprint of an MSR is a fraction of conventional reactors, and the waste is far less radioactive. Storage becomes a completely different challenge, not like the one we have today.

Read more here:

http://www.terrestrialenergyinc.com/msr-waste.html

[SeeGeeWhy]

Haha! That's a pretty wild idea Troutman... but we should probably use it as a fuel resource while we can

[GGG]

Originally Posted by Erick Estrada

Is nuclear energy really a long term solution? The radioactive waste still gets stored on earth and it lasts thousands of years. I realize that the CO2 mass emissions far surpasses what the equivalent radioactive waste would be but annually storing tonnes of radioactive waste on the planet will one day likely result in severe consequences.

Currently in Saskatachewan there is tons of uranium in the shield. As rich as 15% in some areas. Now this isn't enriched to it is less radioactive than the waste product but some of this radiactive material is right near the service. So doing nothing we have radioactive material that is stored in the earth that will last for thousands of years with no protection on how this material interacts with ground water.

If you bury radioactive waste in the Canadian shield you can ensure that it is designed safely to protect against ground water contamination. There are issues with it but in terms of volume it is relatively small. About 2000 tonnes of nuclear fuel are generated each year by the worldwide nuclear industry.

The desity of uranium is 20,000kg per cubic meter (20 tonnes) so the worldwide industy only procuces 100 cubic meters of highly radioactive waste per year. So a 10m by 10m by 10m storage area is the worlds waste for a year. Increasing this 10 or 100 fold is a easily managable problem. Compare it to say the tailings ponds at an oilsands mine which has pretty toxic sludge that needs to be buried at the end and kept out of the ground water.

[photon]

Originally Posted by Erick Estrada

Is nuclear energy really a long term solution? The radioactive waste still gets stored on earth and it lasts thousands of years. I realize that the CO2 mass emissions far surpasses what the equivalent radioactive waste would be but annually storing tonnes of radioactive waste on the planet will one day likely result in severe consequences.

And as you say annually dumping gigatonnes of waste into the atmosphere will definitely result in severe consequences, at least with nuclear waste we know exactly where it is and what we can do with it.

And the waste still retains a huge portion of its potential energy, there are reactor types that can use the waste as fuel. Or other types of reactors that have a fuel cycle that produce waste that is only more radioactive than in-the-ground uranium for 100's of years.

Nuclear doesn't have to be the only solution for sure, solar is the best, but we need to replace coal and the sooner we can the better.

[nik-]

nm

[Fozzie_DeBear]

Originally Posted by troutman

Does radioactive waste have to be stored on the planet? Is it too dangerous/expensive to launch it into space?

http://www.popsci.com/technology/art...lear-waste-sun

http://enenews.com/space-disposal-fo...ama-commission

It would only take 1 Challenger disaster to make a helluva dirty bomb out of that waste

[Coach]

Originally Posted by photon

And as you say annually dumping gigatonnes of waste into the atmosphere will definitely result in severe consequences, at least with nuclear waste we know exactly where it is and what we can do with it.

And the waste still retains a huge portion of its potential energy, there are reactor types that can use the waste as fuel. Or other types of reactors that have a fuel cycle that produce waste that is only more radioactive than in-the-ground uranium for 100's of years.

Nuclear doesn't have to be the only solution for sure, solar is the best, but we need to replace coal and the sooner we can the better.

What about Thorium-based reactors? My brother the geologist was telling me the other day about the cleanliness of Thorium vs Uranium, the little waste it produces comparatively and how plentiful Thorium is on Earth compared to Uranium. Uranium was chosen as the fuel during the first research into nuclear power because of it's weaponization capabilities, wher Thorium doesn't have enough energy to produce a bomb close to the magnitude of Uranium.

I also remember having a conversation with him about Canadian scientists discovering a way to use Uranium in it's unenriched form and thus essentially producing no waste as the waste is produced during the enrichment process, which is again only needed for bombs.

Maybe someone else can shed a little more light on that, but seems like something than can and should be implemented rather quickly.

[troutman]

Originally Posted by Fozzie_DeBear

It would only take 1 Challenger disaster to make a helluva dirty bomb out of that waste

Could a space elevator be safer?

http://science.howstuffworks.com/space-elevator.htm

[ken0042]

We have about a 90-99% success rate with sending items into space with rockets. We have a 0% success rate with sending items into space with a space elevator.

In all seriousness, I think by the time we can get a space elevator engineered and built, we should have the technology for other forms of energy.

Besides, what do you do with the radioactive waste once it's up in space? Dump in on another planet like Venus? Send it to the sun? Would sending radioactive waste to the sun have other impacts to our environment?

[Knut]

Originally Posted by ken0042

We have about a 90-99% success rate with sending items into space with rockets. We have a 0% success rate with sending items into space with a space elevator.

In all seriousness, I think by the time we can get a space elevator engineered and built, we should have the technology for other forms of energy.

Besides, what do you do with the radioactive waste once it's up in space? Dump in on another planet like Venus? Send it to the sun? Would sending radioactive waste to the sun have other impacts to our environment?

No. The radioactive waste would have absolutely no impact on the sun.

As for Feasibility... it is such a small amount, it is likely easier and safer just to bury it in the Canadian Shield.

[Wormius]

Originally Posted by Fozzie_DeBear

It would only take 1 Challenger disaster to make a helluva dirty bomb out of that waste

I imagine they wouldn't send *all* of the material up at once, and it would be protected like a super black-box. There are certain risk mitigation strategies that would have to be implemented.

[photon]

Originally Posted by MattyC

What about Thorium-based reactors?

Yeah there's been lots of talk about that, even was a talk at TEDxYYC a few years ago I think. I know there's been talk about it here before anyway.

China's apparently pushed up their Thorium reactor program: http://www.scmp.com/news/china/artic...-reactors-2024

India I thought was gung-ho on Thorium but not sure what stage they're at.

[Flash Walken]

Originally Posted by troutman

Could a space elevator be safer?

http://science.howstuffworks.com/space-elevator.htm

Originally Posted by Fozzie_DeBear

It would only take 1 Challenger disaster to make a helluva dirty bomb out of that waste

Originally Posted by ken0042

We have about a 90-99% success rate with sending items into space with rockets. We have a 0% success rate with sending items into space with a space elevator.

In all seriousness, I think by the time we can get a space elevator engineered and built, we should have the technology for other forms of energy.

Besides, what do you do with the radioactive waste once it's up in space? Dump in on another planet like Venus? Send it to the sun? Would sending radioactive waste to the sun have other impacts to our environment?

Use a Rail gun to launch that #### into space.

[Azure]

Originally Posted by ken0042

One of the episodes explained this really well. Basically you are right, as a plant or tree grows it takes CO2 from the air and uses the carbon to grow, and releases oxygen. However when a plant dies and decomposes, it releases the CO2 back into the air. Even if an animal eats the plant, the plant eventually turns back into CO2 as the animal burn the energy.

Where we get coal from is that when trees first evolved, it took millions of years for organisms to evolve that could break down the wood. So trees would die, fall, and eventually get buried. They would never get a chance to release their CO2 back into the atmosphere. Until now, when we humans dig it back up and proceed to burn it.

Same thing with oil and gas. They are all deposits of plants that never got a chance to release their CO2 back. Then we go and dig them up and start burning them.

Perhaps we should find a manmade way to capture CO2 from the atmosphere and store it underground while at the same time releasing oxygen back into the atmosphere.

[Azure]

I said this in the other thread, but coal is already being replaced by natural gas plants.

What is going to be the result of that shift in terms of environmental impact?

[photon]

Originally Posted by Azure

Perhaps we should find a manmade way to capture CO2 from the atmosphere and store it underground while at the same time releasing oxygen back into the atmosphere.

Sure, Carbon sequestration is a big area, lots of ideas. http://en.wikipedia.org/wiki/Carbon_sequestration

Alberta has a few big projects:

http://www.energy.alberta.ca/Initiatives/1438.asp

Originally Posted by Azure

I said this in the other thread, but coal is already being replaced by natural gas plants.

What is going to be the result of that shift in terms of environmental impact?

Natural Gas typically makes about half as much CO2 for the same amount of electricity as coal, 1/3 as much nitrogen oxides.

[accord1999]

Originally Posted by Azure

What is going to be the result of that shift in terms of environmental impact?

http://www.washingtonpost.com/blogs/...rcent-in-2013/

Thanks to natural gas (and probably a weaker economy and more fuel-efficient vehicles) the USA actually met its Kyoto Protocol goal!

However, it's overwhelmed by the increase in CO2 emissions from China and India.

[Devils'Advocate]

http://thetyee.ca/News/2014/05/23/Na...ge-to-Nowhere/

The nice thing about natural gas is that it looks good on paper.
The bad thing about natural gas is that it is bad in reality.

Methane does far more damage in terms of GHG than CO2 and methane leaks from natural gas extraction. Of course much of this leaked gas never goes on the books. It's not extracted; it's not burned.... it just goes from the ground straight into the atmosphere and on paper that's just awesome. But we're still getting warmer.