New nuclear power plants are designed to be safe even when run by unsensible humans (up to 72h)
Any nuclear storage has to designed to be safe and secure from the second you close it up, irrespective of what humans will be doing the next thousands of years. (except of course, deliberately opening said storage)
CANDU reactors in Canada, I think are designed to be run by nobody at all.
They require heavy water to keep the reaction going. No heavy water, it just cools down.
If anything 'breaks' - no heavy water, no chain reaction.
I'm grossly oversimplifying, but you get the idea.
I suggest that if we actually put our minds to it, we could develop a kind of 'dumb reactor' that didn't require any kind of intervention at all, other than maintenance.
I question the generally-accepted necessity of such storage. Yes, nuclear waste remains dangerous for thousands of years. But chemical waste such as arsenic and mercury remain dangerous forever, but we don't take anything like those precautions when disposing of those.
No. Our space-time is definately NOT Anti de Sitter (AdS). AdS/CFT is nothing more than very nice mathematics with applications in different fields of physics. It's not applicable to our universe.
In order to help people think about curvature and gravity, look at the following examples:
- The surface of the earth is a 2 dimensional positive curved space. To see this, draw a triangle with corners on the north pole, on the equator near Somalia and on the equator in Equador. The resulting triangle has a sum of all corners > 180 degrees.
- In a negative curved space, the sum would be less than 180 degrees. In a flat space, it is equal to 180 degrees.
- Another way to see the curvature of the surface of the earth is to observe that it's impossible to draw 2 parallel lines that do not intersect.
- The 2D torus (e.q. the surface of a donut) is flat. Test it with triangles.
- The towers of the Verrazano–Narrows Bridge are wider at their top than at their base. This has nothing to do with the earth have a positive curvature. Test it with a torus.
- 3D space is nearly always flat in the universe, especially at the surface of our planet.
- 4D space-time is not remotely flat. If I throw up a ball, it will come down. This is due the mass of the earth curving its surrounding 4D space-time. The straight line for a ball in the curved space-time looks like the ball changes directions and comes down in our flat 3D space.
- If you try to find the triangle of a sphere with the biggest sum of corners, you'll discover that the outside and inside of a triangle are interchangeable. We've entered the field of topology now and this has nothing to do with its curvature.
While I strongly disagree with you on nuclear power (especially since radioactive decay means that 'eternity' by definition is always safe, unlike chemical waste), I strongly agree that "Into Eternity" is a must-watch.
The only real long-term risk to geological disposal are future humans. The question the documentary adresses is 'how to communicate to future generations not to dig there'.
Load-following is both license and technical related in a chicken-and-egg-way. You need to incorporate load-following into your reactor design. More specifically: the speed with which a reactor can modulate its output while staying within nominal operational bounds is a design parameter. If licensing doesn't allow load-following, you're not going to give your reactor that feature.
Since regulations don't allow any other option e.g. the US doesn't allow reprocessing.
Also: what better place to temporarily store nuclear waste in the exact same place where it is produced where safety and security measures are already in place?
First, a containment structure[1] is a key feature in any reactor[2]. These are massively over-engineered specifically to contain even unlikely problems. We learned that this was important after the SL-1 accident[3]. As you suggest, this is a feature designed to fail safely - the containment should keep the rest of us outside the building safe, and doesn't say anything about what happens to the stuff in side.
> meltdown
This term is thrown around a lot, and while solid fuel melting in a traditional reactor is a serious event, a lot of people seem to think that "meltdown" is some kind of terrible or damaging event. The reason people in the nuclear industry panic over a possible meltdown has little to do with safety; up until that point you could - in theory - still reasonably believe that the reactor could be fixed and (eventually) restarted. After a meltdown, you have to assume the core is trashed and is now a financial liability instead of your main source of revenue.
Meltdowns are a terrible event financially. The actual melting of the fuel involves the passive-safety, which are usually designed to drain that fuel into (multiple) areas where it can cool down without criticality risk.
All of this is still discussing very old features. This is like worrying about today's computers because vacuum tubes are fragile and need to be replaced when they burn out. Modern reactor design is very different, because we learned form the problems that happened in the original designs, just like any other technology. Unfortunately, propaganda based on radiophobia has been a serious roadblock. Ironically, this means we're stuck using older designs that should have been replaced decades ago with modern reactors that emphasis passive safety.
If you're interested in a brief overview of these problems (and why some of us believe thorium breeder reactors are the answer for many of these problems), I recommend watching "Th"[4]. Just remember it's an overview, and they skip over some of the details to keep it short.
1. Isn't a business POV or about deadends and it applies to any shift in energy production.
2. I think some geologists are going to want to have a word with him concerning tectonics. Also just because US can't do it, doesn't mean it can't be done. E.g. Finland is doing it.
3. The production cost of nuclear based electricity is very weakly dependent on the price of natural uranium. A doubling of the cost in U-nat results in a cost increase of a few %. Also backstop technologies (U from seawater or Th or bomb deconstruction) are available and technologically viable (though not economically viable with oil below $150)
4. No terrorist is going to build a Pu-bomb. It's orders of magnitude more difficult and expensive than a U-bomb. Moreover, no terrorists is going to 'build' a bomb. Also, reactor grade Pu is unusable for a bomb due to its isotopic composition.
5. I'm calling BS. Freshwater consumption for energy generation is typically a few % if cooling towers are involved. As for coastal NPP's: Fukushima Daini is located 12km from Fukushima Daichi one the same coast yet nothing happened there.
Waste stays very radioactive for millions of years. Even after that remains extremely toxic. Earthquakes, volcanoes, diggers can trigger an apocalypse.
Being very familiar with nuclear waste, I can say that, from a technical pov, it's a solved problem: just put it deep enough to comply with whatever safety level is required. The problem with nuclear waste is political not technical and not economical.
Reprocessing or transmutation are alternatives to handle nuclear waste but they have in common that they're more expensive and even less acceptable to society.
The reverse is actually true. Nobody uses Thorium since you can't make bombs out of them. Thorium is very unsuited to weaponize since one of the byproducts of the fuel process (U-232) decays in to a hard gamma-emitter. This not only makes the material dangerous to handle, it will also wreak havoc with bomb electronics, will require heavy shielding and be very easy to detect.
Due to its unsuitability for bombs, the militaries of the world (in the '50s) didn't invest into researching Thorium. Industrial inertia (and sunk costs) and Uranium being good enough lead us to where we are today.
It is 'technically' possible to make a U-233 bomb but the effort required is so far above U-235 bombs that for any nation able to do the former, it's much easier and cheaper to do the latter.
