Lasers could cut lifespan of nuclear waste from a million years to 30 minutes

You can do that with fusor. It does direct acceleration without laser generation losses.

Doing dt fusion to make neutrons for other purposes is a pretty common technique in general. It sounds like the twist is using lasers to provide the energy instead of a traditional accelerator. Commercial neutron generators that exist now can approach fluxes comparable to that in small reactors, but the main difference is the energy distribution. Reactors are much more low-energy dominated so it's true that other reactions can become accessible with a high energy quasi monoenergetic source. However, i think we are still missing orders of magnitude of capability before it could become feasible. On top of that, laser based facilities like NIF are probably the most expensive and slowest-repeating way to generate neutrons right now. Plus when you make that many neutrons alot of other stuff will end up getting activated and pottentially become waste itself.

Personally i think there also need to be some nuclear chemistry advances to be able to efficiently and cleanly separate isotopes before they can be transmuted. There is some neat work being done on this by people at FRIB trying to extract medical isotopes etc from the beam dump.

Okay well I am not a particle physicist, but I did design and build laser plasma ablation devices, and I will echo the skepticism of the particle physicist.

> easy to reach MeV scale

Thermal photons in MeV!? Whoa. Going to need a citation on that one.

The first 2 papers indicated by you refer indeed to the same thing as the article that started this thread, but they explain the possible method.

The principle is very similar with the sources of deep ultraviolet light used for photolithography. The laser pulses are used to produce hot plasma and to accelerate the electrons from plasma, which hit then a target, like in the traditional X-ray tubes. The interaction of the accelerated electrons with the target produces gamma rays. Finally, the gamma rays can be used to transmute the nuclear waste.

There are 2 problems with this approach. As everybody knows, improving the deep UV sources to have an intensity great enough to be usable in the production of integrated circuits took several decades and many billions of dollars.

The gamma ray sources that would be needed for waste treatment are significantly more complex and the output intensity must be much higher, so it is impossible to guess how much time and money would be needed, but certainly much more than for photolithography.

The second much more serious problem is that already mentioned in another post. If these gamma-ray sources would have a global efficiency of 1%, starting from the electrical input power, passing through pump diodes for lasers, then solid-state lasers for pulse generation, then heating plasma, accelerating electrons, radiation from the electron target and finally absorption in the nuclear waste, that would be an amazing achievement.

Actually a global efficiency of less than 1 per ten thousand would be more likely today.

The energy required to transmute all the waste from a nuclear reactor might be of 10% or more of the output energy of the reactor. Multiplied with a factor between 100 and 10000, the result is that a nuclear reactor would not be a net producer of energy, but a huge consumer of energy, making it useless.

A little more realistic would be to not treat all the nuclear waste, but only 1 or a few especially dangerous isotopes, e.g. only the radioactive iodine.

While this would reduce a lot the energy required for transmutation, a lot of additional energy would be needed for the separation of the desired isotopes from the radioactive waste.

Maybe transmuting only the iodine could be done in a distant future with a little less energy than the nuclear reactor produces.

However that would not solve the problem with the storage of the nuclear waste. Consuming a huge amount of energy with the elimination of the iodine would only lessen the danger of what would happen if the storage of the waste would be compromised and the waste would be dispersed into the environment (because the vertebrates extract the iodine from the environment and concentrate it into the thyroid, so radioactive iodine is dangerous even at smaller concentrations than the rest of the waste).

It never really occurred to me that transmutation is a reputable field of scientific study nowadays.

> there is no gamma-ray source of sufficient intensity to treat a macroscopic quantity of waste.

If you get some of the waste to start producing neutrons and gamma rays through stimulated fusion, couldn't you harness those products to speed the decay of other nearby waste atoms? Sure, you might need a moderator, but can you more or less stimulate a sort of chain reaction?

Eh. Most of it’s in the air, where you can’t see it. Or in your lungs. Either way we clearly don’t need to deal with it.

Consider the vastly larger quantities of naturally-occurring arsenic, lead, mercury, etc. in the world, and how - in spite of our seeming efforts to expose billions of people to them in their most dangerous forms - they aren't exactly wiping out humanity.

Most of the material isn’t readily water soluble and a lot of the radiation is alpha particles which aren’t very dangerous. The really dangerous stuff has a half life on the order of minutes/days/months. It’s also hard to breath in the particles unless they’re attached to something like smoke. Uranium miners in the 50s who didn’t smoke had cancer rates no higher than the general population.

Huh? The volume of toxic solvents, gasoline byproducts, carcinogenic substances emitted every second by cars trundling around dwarf this.

That amount could be baked into glass and stored in sets of giant steel casks and would never meaningfully interact with humans ever again.

It is not only the density, but also the purity of Uranium which makes a difference. Weapons grade uranium is 99.3% pure U235 or more by mass. Reactor grade uranium could be between 90-94% at most (the last I had read). It isn't worth economically to enrich further. If the purpose is to reach sustained criticality, this purity is enough to heat the fuel-rods.

Although it may not seem a lot, the 6% impurity is enough to act as a neutron damper (for runaway chain reactions). Consequently, you need an order or two higher density with reactor grade Uranium to make it go supercritical & have uncontrolled fission - something that does not happen in normal circumstances.

Molten salt fuel cycles where waste products may be separated from the liquid fuel through more conventional chemical separation methods seem like a simpler solution. It's too bad about the negative public view on nuclear. I think next gen fission power research deserves greater funding.

It's cheaper to dig up and refine uranium ore instead so the economics don't make sense.

Most waste is actually from other things, not fuel. Anything your nuclear material comes into contact with is treated as waste. But obviously due to this there's drastically different levels of radioactivity in waste (but everyone acts like it's all fuel waste)

Not the way it’s normally described, U238 is relatively worthless outside of being used in bullets etc.

What we currently care about is the 235 which is actually burned up by the reactor down to close to the ratio in natural fuel. Reprocessing for current designs would result in most of the fuel being discarded as depleted uranium the same way the normal enrichment process works.

The actual way around this is to directly use natural uranium without enrichment via CANDU or similar design. https://en.wikipedia.org/wiki/CANDU_reactor No need for enrichment or reprocessing.

Classic example of talking past each other.

The previous poster is clearly right in the bigger picture. You don't treat hydrogen as a scary radioactive material!

There's a sweet spot. So you are bott right and both wrong ;)

Started looking ten years ago. Construction itself will take ten years. And years away from selecting and expropriating the site. There’s no good excuse to not be halfway there by now. It’s a make-work project. Some small organization is dragging this out because it pays well to never finish.

Edit: sorry, it’s that this sort of never-ending government project is all too common in Canada. Military procurement is an especially sore point right now, atrociously delayed.

I don't know anything about this but are you saying there's nothing to worry about here?

The thing is, the "slightly dangerous thing" (i.e., uranium with all its associated breakdown products) occurs naturally in vast and totally uncontrolled ore bodies, sometimes right in contact with the water table. Yet somehow we're not worried about that (except in a very few cases where the concentration is extremely high). Why not?

It's like the way that no one gives a crap about the natural oil seeps off the coast of Southern California, which dump about 5 million gallons per year right into the ocean, then they have a panic reaction when a boat accident dumps a couple of hundred.

yea i guess i don't understand how its possible for these elements to be safe before we extract it but unsafe to put it back in a depleted form? and if its not depleted why can't we keep using it until it is?

The fuel going into a reactor has a tiny amount of radioactivity. The technicians handling fresh fuel bundles don't need lead lined protective gear, just some gloves and clean room procedures to keep the technician's greasy grubby paws off the highly refined and expensive fuel bundles.

https://nrcpublicblog.files.wordpress.com/2015/02/fuelrods.j...

That technician probably works with nuclear fuel every day and he's exposed to far less occupational radioactivity than a flight attendant because at higher altitudes there's less atmosphere to attenuate cosmic radiation. Even orders of magnitude more concentrated doesn't lead to some extreme amount of radiation. If it hasn't gone critical then the radiation hazard is negligible outside your body. In fact, if you were to finely grind up some Uranium and chemically process it into some biologically absorbable form and ingest a lethal amount the heavy metal poisoning would be lethal before the radioactivity.

>Also yes many of the byproducts are more radioactive than the fuel.

That's the understatement of the year. The fission products are extremely radioactive and are responsible for the massive amounts of shielding and care needed around high level nuclear waste.

>The stuff in the dirt tends to be comparatively stable - the unstable stuff decayed long ago.

Also not true, the stuff in the dirt has been constantly decaying and building up to a steady state decay chain in proportion to the half life of each isotope and the production rate of it. Fresh fuel is basically entirely Uranium with almost no decay products whereas all the radon that seeps up in basements all comes from radioactive decay of unstable isotopes underground. "The stuff in the dirt" is responsible for around 21,000 lung cancer deaths every year in the United States.

Btw, most waste is from #2 and not #2. #2 is where the dangerous waste is from but that's also only ~3% of the total waste. One of the issues is people report the total waste and treat it as if it's all the same.

so why not keep using it? if the reactor creates even more radioactive material then the initial material?

As far as I can see, there isn't a single waste incident anywhere in that list.

It kind of looks like you googled for something, didn't read it, and started arguing.

Looks like the only thing even mentioned there is that in the 1950s, there was an incident, and someone who isn't a doctor made an estimate that some cancer deaths might have happened later. Amusingly, it's the same person who predicted 20 million deaths from Chernobyl, and still insists they happened and are being covered up.

Can you tell me which specific disagreement you see there? I'd like to think you're not listening to the guy who says there were three secret holocausts worth of death in the 1990s.

I agree that's a pretty strong statement to make but most of the accidents didn't have anything to do with the "waste" and more with the fuel and reactors. I would argue we're not talking about a lot of people though, compared to the billions that climate change is going to affect not to mention the millions that are already affected by pollution and other carbon-based energy production effects.

This seems to be a very broad definition of 'nuclear waste'. When I search for "waste" on that page, I find one incident, involving a waste furnace explosion (not the waste itself) and a second one in Russia in 1957 where a large amount of waste was released with no immediate fatalities, but possibly 200 later excess deaths. And, as the page points out, coal burning power plants emit (with little or no long-term "containment") 100-times as much radioactive waste.

The argument against nuclear power is safe disposal of the "waste", but, as the OP pointed out, it is hard to find any examples of deaths because of nuclear waste (there certainly have been more deaths because of accidents, but even here, coal mining/burning/waste disposal clearly is much higher risk, even ignoring CO2 output).

I suppose that parent comment is trying to say that given our history with nuclear waste, especially with the increasing caution, it hasn't caused any (significant) incident by the waste

First, yes I agree that nuclear waste is an important issue that should be getting more attention than it does. However, this should not be thought of as a 10,000 or more year problem. Think back on the incredible expansion of knowledge in the last 100 years. Do we really believe that in another 100 years or so we won't have a way to safely reprocess this waste? This is a one or two hundred year problem at most. Can we not safely store two or three warehouses of material for 100 years? Thinking of this as a ten or fifty thousand year problem expresses a tremendous pessimism in the human ability to innovate.

I believe the argument is that it may be the lesser of many evils, not that it's harmless. I think it's a matter of evaluating our remaining realistic alternatives. Like:

1) Re-embrace nuclear power, do our best to safeguard the waste, knowing that someday (50? 100? 10,000 years?) from now, it will be an issue we'd have to deal with. It may be at a local, national, or global scale... hard to say. Could leak naturally, from unexpected disasters, terrorism, warfare, whatever. But it buys us some time, and can help slow down climatic impacts so the world has a few more years to adapt. It still won't be pretty.

2) Pretend like the world is suddenly going to get behind renewables and clean energy and drastically cut emissions AND recapture much of the carbon we emitted already. One, this isn't going to happen, and two, it's already too late. Best case, this makes the future decades a bit better for first world countries, but it's already too late for most of the rest of the world.

3) Do nothing: The mostly likely outcome, with or without more nuclear power. Life carries on, many humans will perish from climate change domino effects (draught, floods, desertification, habitat loss, whatever) and the resulting international instability. Many more other species will perish. The remaining life will adapt and carry on, and the world keeps going, but it's gonna be a painful few decades/centuries and our kids will hate us, but on the plus side, we've been saying that for decades now so it's already an intergenerational norm. Each generation leaves the world a little worse for the next, until enough humans die off, the planet recovers a little, and we do it all over again.

Arguably embracing nuclear power is the least evil of these realistic remaining options, though it's highly unlikely enough people and nations could be convinced. People in the aggregate are phenomenally bad at evaluating risk, especially long-term, whether it's nuclear or climate impacts, so absolutely nothing will get done.

But the advocacy isn't wrong in and of itself... nuclear is a measure of last resort, especially now that the IPCC has proven completely ineffective at persuading countries to take other meaningful measures. Nuclear can't save us, but it can lessen the pain to come a little bit, kinda like hospice for the planet.

> We already can't get a grip on climate change and plastic waste, let alone waste that has to be stored safely for 700 million years.

Please stop it with the physics theater. This stuff doesn't need to be stored for 70 years, let alone 700 million.

Nuclear waste from a modern reactor is touch-safe. Not touch-safe in 50 years. Not touch-safe next week. It comes out of the reactor touch-safe. You just have to wait for it to cool down to room temperature.

It's eat-safe in under ten years.

I have no idea why anyone would look at someone saying "700 million years" and not be reduced to peals of laughter. Did you just look up the half-life of uranium 235 or something?

The goal isn't to get rid of the uranium

Why would you need that? There's uranium all over your house, right now. You know you eat tiny pieces of your plates constantly, right? I sure hope you don't own any Fiestaware. Uranium is perfectly safe, and in lots of your consumer products. Stop learning safety from Marvel movies.

In 700 million years, if you actually had a dangerous energy source, life would have evolved to make it food by then. You know, like the black mold did with the space station in under a hundred, from a zillion miles away?

The ultra-hot stuff that you're taught to fear never actually comes out of the reactor.

The French glass their waste and put it in the floor, as a tourist attraction. They walk on top of it, no metal cladding, five foot gap. They've been doing it 40 years.

Just how radioactive do you think this stuff is?

Do you understand that hot springs like Yellowstone are way more radioactive than radioactive waste?

Do you understand that we go bathing in those? (They're actually pretty nice, once you get used to the smell of sulfur.)

Are you about to give me some mess about the kind of radiation? You going to try to teach me about roentegens vs grays? Look it up first. It's not going to play out the way you expect.

Holy shit, man, look at the numbers.

Like. Have ... have you ever looked at how much radiation you get from a TV tower? Have you ever checked where the closest TV tower is to you?

The same people that are terrified of nuclear waste think there's nothing wrong with cell phone radiation. It's baffling to me. You get *so* *much* more radiation from a pair of bluetooth headphones than you ever will from nuclear waste

I've got like ten bluetooth transponders around me just because I find cables annoying, and a cell phone in my pocket right now

You know that football field of nuclear waste barrels that doesn't exist on the entire planet, but that John Oliver keeps pretending is a lot to save the entire planet?

Go on, find it. Move one barrel out of the middle. Sit there. Bring your iPhone and a radiometer.

Now hold your iPhone high enough up that the large amount of metal won't block your cell signal.

Check the radiometer.

Do you think you see more energy in the cell phone band, or all the others put together?

Ooooooooh, better protect against that for (checks watch) 700 million years.

And not, you know, the loss of the ecosphere.

.

> Are you kidding me?

No, I am not kidding you.

It's never killed anyone and it's never going to, no matter how much public panicing you do.

If you cannot name a single person that's ever been killed by it - if it's safer than making bread flour and safer than skateboards, but it can stop climate change - then it's time to settle down.

You're quoting the half lives of things that aren't even in the barrel, and you want to be taken seriously as some kind of source of knowledge.

Stop.

This is dishonest.

Climate change is real. Solar power doesn't work. Wind power doesn't work.

Nuclear power does work, and has the best safety record of any power system, almost by a factor of ten.

If the most you can do is pretend there will be death someday, by mechanisms you can't describe, involving the wrong numbers and things that aren't present? Then you shouldn't be part of the discussion.

The engineers and physicists do not agree with your future visions.

I'm not willing to watch climate change destroy the planet I live on today, just because you think something bad will happen millions of years from now which the physicists say is wrong.

Climate change is killing millions of people, today, and threatening biodiversity and the continental food supply

We can stop it, but you're sitting here saying "but in millions of years" and you aren't even correct

.

> The mentioning of human history is pretty useless and misleading because

It's what really happened.

You're literally saying "ignore reality, ignore history, ignore the scientists, and pay attention to my scary stories."

No; I don't think that I will.

I've taken the relevant classes. They do not teach the things that you are saying.

The second you say "reject the evidence of history," you have condemned any argument you could possibly make

.

> but it will exists more than 2,000 times longer than mankind exists so far.

No, it won't. You just don't understand the physics involved. The actual hot products in those barrels don't even make it 10 years. Even the old ones didn't make it 50.

Kyshtym was actually the worst nuclear disaster in history, not the second or third. Kyshtym was not actually caused by nuclear waste. In reality, the Russians were keeping hot fuel underground, and cooling it with water, a bizarre and wildly inappropriate design.

A pump failed, and one of the water circuits stayed for more than a year.

Eventually there was a steam blast.

It had nothing to do with nuclear waste. It was a cooling system failure. The blast was 100% non-nuclear.

As the worst disaster in nuclear history, the UN estimated death count is still below 80, and the actual known death count is 31.

Trying to hold this up as some kind of serious risk, and playing the "technically correct, the best kind of correct" card, and using extremely heated language like "blatantly false," is just flat out destructive.

Not only is your story incorrect, but even if it was correct, this kind of "disaster" is so small as to be irrelevant. Any major city on Earth has ten death counts like that a year and you can't name a single one in your city.

This is how we stop climate change.

Stop playing technicality fodder. You aren't as correct as you think you are, and even if you were correct, you'd be making the wrong call in the long run.

If the worst disaster the industry has had in history doesn't add up to a bus accident, and it's already 20% of the way done stopping climate change?

Then it's time to stop getting your rocks off to being able to say "but this one time it killed a couple dozen people 75 years ago."

Especially because it absolute did not, and your claim of "blatant falsehood" is just you mis-learning history from HBO.

Be clear: the maple syrup industry has two disasters with a higher death count in the same time frame.

If you aren't calling for a global moratorium on delicious breakfast syrup, which cannot stop climate change, ask yourself why you need to drag out your knowledge of a trivial event 75 years ago, here.

By the numbers, nuclear power is the safest technology of any kind in history.

If you have to go back 75 years to find 50 dead folks, and you don't understand what a magically high quality safety record that is, please let other people handle this discussion.