Safe nuclear refers to many different new gen4 reactor units that rely on passive safety instead of engineered safety. The real difference comes with a slight bit of understanding of how nuclear tech works now, and why that isn't optimal.

Let us first consider this, even with current nuclear technology, the amount of people that have died as a direct and indirect result of nuclear is very low per unit energy produced. The only rival is big hydro, even wind and solar have a great deal of risk compared to nuclear as we do it and have done it for years. The main difference is when a nuclear plant fails, everyone hears about it...but when a oil pipeline explodes and kills dozens, or solar panel installers fall off a roof or get electrocuted and dies...it just isn't as interesting.

Pound per pound nuclear is already statistically very safe, but that isn't really what we are talking about, we are talking about what makes them more unsafe compared to new nuclear techs. Well, that has to do with how normal nukes work. So, firstly, normal reactor tech uses solid fuel rods. It isn't a "metal" either, it is uranium dioxide, has the same physical characteristics as ceramic pots you buy in a store. When the fuel fissions, the uranium is transmuted into other, lighter, elements some of which are gases. Over time, these non-fissile elements damage the fuel rod to the point where it can no longer sustain fission and need to be replaced. At this point, they have only burned about 4% of the uranium content, but they are all "used up". So while there are some highly radioactive fission products contained in the fuel rods, the vast majority is just normal uranium, and that isn't very radioactive (you could eat it and not really suffer any radiation effects, now chemical toxicity is a different matter). The vast majority of nuclear waste, as a result of this way of burning uranium, generates huge volumes of waste products that aren't really waste products, just normal uranium.

But this isn't what makes light water reactors unsafe compared to other designs. It is all about the water. Normal reactors use water to both cool the core, extract the heat, and moderate the neutrons to sustain the fission reaction. Water boils at 100c which is far to low a temperature to run a thermal reactor on, you need much higher temps to get power. As a result, nuclear reactors use highly pressurized water to keep it liquid. The pressure is an amazingly high 2200psi or so! This is where the real problem comes in. If pressure is lost catastrophically, the chance to release radioactivity into the environment increases. This is further complicated by the lack of water then cooling the core. Without water, the fission chain reaction that generates the main source of heat in the reactor shuts down, however, the radioactive fission products contained in the fuel rods are very unstable and generate lots of heat. So much heat over time, they end up causing the rods to melt if they aren't supplied with water. This is the "melt down" you always hear about. If you start then spraying water on them after they melt down, it caries away some of those highly radioactive fission products with the steam. This is what happened in Chernobyl, there was also a human element that overdid all their safety equipment, but that just goes to show you the worst case.

The same thing didn't happen in Fukushima. What happened in Fukushima is that coolant was lost to the core and they started to melt down. The tubes which contain the uranium are made from zirconium. At high temps, water and zirconium react to form hydrogen gas. Now modern reactor buildings are designed to trap gases, usually steam, in the event of a reactor breach. In the case of hydrogen, that gas builds up till a spark of some kind happens and causes an explosion. These are the explosions that occurred at Fukushima. Both of the major failures and dangers of current reactors deal with the high pressure water; but water isn't needed to make a reactor run, just this type of reactor.

The fact that reactors have radioactive materials in them isn't really unsafe itself. What is unsafe is reactor designs that create a pressure to push that radioactivity into other areas. A electroplating plant, for example, uses concentrated acids along with high voltage electricity in their fabrication processes. It "sounds" dangerous, and it is in a certain sense, but it is a manageable danger that will most likely only have very localized effects in the event of a catastrophic event. This is due mainly to the fact that there are no forces driving those toxic chemical elements into the surrounding areas...they are just acid baths. The same goes for nuclear materials, they aren't more or less dangerus than gasoline (gas go boom!), if handled properly.

I think one of the best reactor designs in terms of both safety and efficiency are the molten salt reactors. They don't use water as a coolant, and as a result operate at normal preasures. The fuel and coolant is a liquid lithium, fluoride, and beryllium salt instead of water, and the initial fuel is thorium instead of uranium. Since it is a liquid instead of a solid, you can do all sorts of neat things with it, most notably, in case of an emergency, you can just dump all the fuel into a storage tank that is passively cooled then pump it back to the reactor once the issue is resolved. It is a safety feature that doesn't require much engineering, you are just using the ever constant force of gravity. This is what is known as passive safety, it isn't something you have to do, it is something that happens automatically. So in many cases, what they designed is a freeze plug that is being cooled. If that fails for any reason, and you desire a shutdown, the freeze plug melts and the entire contents of the reactor are drained into the tanks and fission stops (fission needs a certain geometry to happen).

So while the reactor will still be as dangerous as any other industrial machine would be...like a blast furnace, it wouldn't pose any threat to the surrounding area. This is boosted by the fact that even if you lost containment AND you had a ruptured emergency storage tank, these liquid salts solidify at temps below 400c, so while they are liquid in the reactor, they quickly solidify outside of it. And another great benefit is they are remarkably stable. Air and water don't really leach anything from them, fluoride and lithium are just so happy binding with things, they don't let go!

The fuel burn up is also really great. You burn up 90% of what you put in, and if you try hard, you can burn up to 99%. So, comparing them to "clean coal" doesn't really give new reactor tech its fair shake. The tech we use was actually sort of denounced by the person who made them, Alvin Weinberg, and he advocated the molten salt reactor instead. I could babble on about this for ages, but I think Kirk Sorensen explains that better than I could...hell most likely the bulk of what I said is said better by him



http://www.youtube.com/watch?v=N2vzotsvvkw

But the real question is why. Why use nuclear and not solar, for instance?

http://en.wikipedia.org/wiki/Energy_density

This is the answer. The power of the atom is a MILLION times more dense that fossil fuels...a million! It is a number that is beyond what we can normal grasp as people. Right now, current reactors harness less that 1% of that power because of their reactor design and fuel choice.

And unfortunately, renewables just cost to darn much for how much energy they contribute. In that, they also use WAY more resources to make per unit energy produced. So wind, for example, uses 10x more steal per unit energy contributed than other technologies. It is because renewables is more like energy farming.

http://videosift.com/video/TEDxWarwick-Physics-Constrain-Sustainable-Energy-Options


This is a really great video on that maths behind what makes renewables less than attractive for many countries. But to rap it up, finally, the real benefit is that cheap, clean power is what helps makes nations great. There is an inexorable link with access to energy and financial well being. Poor nations burn coal to try and bridge that gap, but that has a huge health toll. Renewables are way to costly for them per unit energy, they really need other answers. New nuclear could be just that, because it can be made nearly completely safe, very cheap to operate, and easier to manufacture (this means very cheap compared to today's reactors as they are basically huge pressure vessels). If you watch a couple of videos from Kirk and have more questions or problems, let me know, as you can see, I love talking about this stuff Sorry if I gabbed your ear off, but this is the stuff I am going back to school for because I do believe it will change the world. It is the closest thing to free energy we are going to get in the next 20 years.

In reply to this comment by ReverendTed:
Just stumbled onto your profile page and noticed an exchange you had with dag a few months back.
What constitutes "safe nuclear"? Is that a specific type or category of nuclear power?
Without context (which I'm sure I could obtain elsewise with a simple Google search, but I'd rather just ask), it sounds like "clean coal".

What about reactors that can't melt down? What about Ford Pintos that exploded when you hit them from the rear, that isn't a story of why all cars are dangerous, only Ford Pintos. What about a plane lands on a city and kills thousands, or the super dome and 10s of thousands? What if what if what if. 50 million people is a little showing of being irrationality scared. Even in the worst designed reactor incident in history, it wasn't as bad as that. If you looked closely, as well, the chart shows that nuclear has historically been safer that solar and wind (and hydro if you include the Banqiao Dam incident).

With that said, I do wish to see old light water reactor technology phased out and new, walk away safe reactors phased in. Engineered safety is less preferred than intrinsic safety that many of the new reactors have. Also, lets not forget, most of the navy is nuclear...meaning they feel safe enough to be in war time situations with current reactors, so engineered safety can indeed be very safe.

I have irrational fears as well, I hate to fly even though I know statistically it is safer than driving. I would suggest that your fear of nuclear is of the same nature. The only way you can kill millions of people with current or future nuclear technology is with bombs, not reactors. The only way reactors can "explode" is from a steam explosion or a hydrogen explosion...so about as bad as a fuel plant exploding, most likely several orders of magnitude less. IE, reactors explode chemically, not via fission, making no more or less dangerous that that other kinds of tech, with the exception of the fission byproducts. The good thing about most of the new nuclear tech is the fuel burn up rates are very very high, meaning there is less fuel involved in most cases.

At any rate, don't take my word for it, there is lots of data out there to look over. For my part, I think nuclear is the cleanest, safest bet for energy needs. I submit that nuclear is only scary because of it was first developed as a fearsome weapon. But the even more fearsome weapon are thermonuclear weapons, which are actually fusion/fission hybrid bombs. I would imagine for whatever reason you aren't super scared of fusion, and would wager that if thermonuclear bombs were called fusion bombs, the world at large would have a different mindset towards it...irrationally.

But I leave you with the facts, nuclear has been the leading sources of clean power which has also caused the least amount of deaths than other technologies. There are many factors in that, including massively engineered safety that continues to improve, as well as highly trained crews that watch over them. Coal miners die all the time, pipelines explode, oil platforms explode, people fall off roofs, or fall off wind farm towers, or get electrocuted...but none of these deaths cause the downfall of those technologies. Nuclear still has more drama in our minds, so plays out much differently when something goes wrong, which isn't very often ( 6 fatal occurrences since 1961) .

>> ^Yogi:

>> ^GeeSussFreeK:
http://nextbigfuture.com/2011/03/deaths-per-twh-by-energy-source.html


I'm sorry are you comparing death rates between Coal and Nuclear Reactors? What if there's a meltdown or a terrorist attack and suddenly there's 50,000,000 people dead? It only takes one reactor outside of LA to do catastrophic damage you cannot compare the two NOW when we don't have a Fuckton of Reactors near population centers.
Comparing the two at this point in time is just ridiculous, the numbers are so skewed it's not even funny.

I want a dyson sphere. Get some people on that, could ya?
>> ^ChaosEngine:

>> ^gwiz665:
Nuclear is not perfect, but it's the best we have right now. Coal and Oil are much worse. Wind, Solar and Geothermal are better, but not nearly the same scale as Nuclear.

There are several issues with nuclear and Chernobyl/Fukushima style disasters are frankly the least of them.
Leaving aside the obviously thorny issue of waste management, the other issue arises when you amortise the cost over the total lifetime of the nuclear plant. It's just not that cheap in terms of energy or money to build, run and then decommission.
As for renewable energy, it's nowhere close to providing the energy levels we need yet. Also there are other environmental issues with some renewable energy generation methods as well. Hydro requires large dams (concrete is an eco-nightmare) and can destroy habitats. Geothermal can affect the landscape (subsidence and sapping geysers are two common effects). Lots of people complain about wind turbines as visually unappealing (personally I find the aesthetically pleasing). I'm not saying renewable technologies are bad, merely that there are still issues with them.
In real terms, fusion is where it's at.

>> ^gwiz665:

Nuclear is not perfect, but it's the best we have right now. Coal and Oil are much worse. Wind, Solar and Geothermal are better, but not nearly the same scale as Nuclear.


There are several issues with nuclear and Chernobyl/Fukushima style disasters are frankly the least of them.

Leaving aside the obviously thorny issue of waste management, the other issue arises when you amortise the cost over the total lifetime of the nuclear plant. It's just not that cheap in terms of energy or money to build, run and then decommission.

As for renewable energy, it's nowhere close to providing the energy levels we need yet. Also there are other environmental issues with some renewable energy generation methods as well. Hydro requires large dams (concrete is an eco-nightmare) and can destroy habitats. Geothermal can affect the landscape (subsidence and sapping geysers are two common effects). Lots of people complain about wind turbines as visually unappealing (personally I find the aesthetically pleasing). I'm not saying renewable technologies are bad, merely that there are still issues with them.

In real terms, fusion is where it's at.

Hmmm, never thought about it before, but hydro pistons make a lot of sense. Water doesn't fatigue, or rust, or really break down in the typical metal fashion. And if it gets corrupted in some sort of way, flushing an area free of water would be a easier than replacing an entire metal rod. Problems would include excess pressure from evaporation as well as how do you extract rotational energy from a water piston. Throwing my thinking cap on the thinkgeneering this for a bit

Wave and solar power are where the investments should be made

Oh for... SIGH. From the Energy Information Administration...

http://en.wikipedia.org/wiki/Cost_of_electricity_by_source

The most efficient forms of energy are Coal, Coal, Coal, Natural Gas, Natural Gas, Natural Gas, Natual Gas, Natural Gas, and Nuclear. In that order.

The LEAST efficient forms of energy are Hydro, Biomass, Geo, Solar, Wind, and Wind.

Anyone notice anything interesting about the list there? Anyone? Beueller? Bueller?

"Green" energy is an absolute joke. America has enough Coal, Gas, and Oil to last well into the next century. Sure - put R&D into Solar, Wind, and Tidal - but swapping over to these forms of energy "right now" just for the sake of it is the height of idiocy. You swap energy sources when they make sense - not because of some moronic hoax (I.E. AGW).

That a real American President likes only America, and no other countries?

No – a real American President can like other countries, but has to like America more.

and what about all that fanatical secrecy in hiding his past

All the Bush stuff does nothing but prove my point. There was enough shady stuff in Bush’s past for conspiracy theorists to hang a hat on. Obama is 10X worse. So when conspiracy theorists come along, the average person may not believe the extremes – but there’s more than enough flesh on the skeleton to make them have enough doubts to not dismiss it entirely.

But let's get real. It isn't just the GOP here that is driving this story. The issue here is that Obama's numbers are plummeting across the ENTIRE spectrum. Obama has been hemhorraging Independants, Moderates, and even DEMOCRATS for months. His policies are complete failures. His objectives are counter-intuitive disasters. The people gave him a chance, and he blew it. So they're dumping this epic-fail and in response he's getting desperate.

I'm 100% certain he was sitting on his birth cert and WAITING for just ONE serious GOP contender to start carping about it. None of them ever did. I'm also 100% sure that Trump has no intention of really running. But when he started trending up in the polls, Obama decided to pull the trigger. It wasn't what Obama wanted, but it woudl have to do because clearly all the REAL opponents were not taking the bait.

Then Obama gives a stupid speech about the birth certificate where he is literally WHINING like a moronic jackass about how he's got "important stuff to do". But for two WEEKS he's been doing nothing but going out and FUNDRAISING for his re-election. Total hypocrite. So whatever good will he thought he was going to get just went right out the window. And his poll numbers tanked again. No surprise there.

Tell me what magical wand Obama will wield to bring down gas prices.

The magic wand is a SENSIBLE multi-pronged energy policy. For decades the US policy on domestic energy production has been one of constriction, restriction, and eviction. Permits are denied. Lawsuits are constant. The cost of doing business is so high that companies go overseas, leaving domestic energy production hanging by its fingertips and with very little wiggle room when events start causing uncertainty in the market. A sensible policy would support aggressive domestic production of ALL energy sources – fossil, nuclear, bio, hydro, geo, solar & wind – not just one or two of them. ANY policy would be better than Obama's. His plan is to cram everyone in $50,000 golf carts.

>> ^GeeSussFreeK:

So brilliant it's stupid it hasn't been thought of till now.


It would be stupid if it hadn't been thought of by now, but it has. Underwater turbines to put into rivers for electrical power have been around for several years. I remember find several when researching remote energy production. Of course that was about 3 years ago and I don't remember it being something commonly popped up in my research, but there were definitely underwater turbines available at that time.

Your video, A Hydro Electric solution without the "Dam" problem, has made it into the Top 15 New Videos listing. Congratulations on your achievement. For your contribution you have been awarded 1 Power Point.

You hit the kill switch as well when your engine is running horizontally so it does not hydro lock on ya and fuck stuff up.

Sometimes I wonder if you really believe anything you actually write.


>> ^quantumushroom:
"A few smoke stacks"?
Yeah, those evil smokestacks, a side effect of allowing people to have energy to heat their homes and cook food and have manufactured items that save millions of hours of manual labor. Those.

All well and good when that was the only way we knew how to make energy. But seeing as now we know how to use solar, wind, wave, thermal, hydro etc. I think it's perfectly agreeable to suggest that maybe we could be using forms of energy creation/capture that do not pump toxins into the atmosphere. I mean, really, you think that what we, as more than 6 Billion people, do has no effect on the earth? You are truly imbecilic.

I really don't get your mindset, well, other than being someone who can't be stuffed actually making an effort, and likes big cars, huge wasteful lives and does all he can to somehow delude himself into thinking it's not a hugely selfish existence.

Which I think is where most right wingers come from, the point of selfishness. If they are comfortable, no matter how badly that life affects others, they want to keep their 'stuff' and not have to change.

Awesome, but my only gripe is he talks about his vehicle being zero pollution, which is only true if he gets electricity from hydro or solar. All those lead batteries are not much more environmentally friendly than the exhaust spewing Corvette racing him

It can't be a B.C. Beaver: it doesn't reek of hydro and go on about how fuckin' cool Phish was back in the day.

I 100% agree. I've seen several "Clean Coal" billboards, and they make me angry. Carbon sequestration is simply delaying the inevitable. It's still a fossil fuel, should not even be mentioned in the same sentence as renewable energy, such as hydro, solar, wind.

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