Why Aren't We Recycling Used Nuclear Fuel, part 1
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- Опубликовано: 8 ноя 2024
- Dr. Steve Piet addresses why we aren't recycling used nuclear fuel in the U.S. The 1-hour talk given to Friends for Learning, April 3, 2015, in Idaho Falls, Idaho. The topic involves technical, political, and historical factors. The talk includes a caution that the current U.S. approach merely repeats what was done in the 1980s and we know how that movie ended. The talk ends with a suggested improved approach that has a greater chance of succeeding.
Part 1
• Why Aren't We Recyclin...
Part 2
• Why Aren't We Recyclin...
Part 3
• Why Aren't We Recyclin...
Part 4
• Why Aren't We Recyclin...
I'm glad that I chose to major in nuclear engineering. This is fascinating!
I'm going into grade 11, and I've decided that I'm going to major in nuclear engineering as well. The topic intrigues me so much
Hope you find a way to recycle the waste or create a new tech fussion reactor.
Recycling & fussion must be the future.
@@3User Curious to know if you ended up in nuclear engineering ?
Yeah curious to know if you 2 entered into nuclear engineering. If you've hit some problems maybe we can discuss some solutions.
(1) How do you quantify “high heat”?
(2) How hot is so called “high heat” waste material?
(3) If placed in water by how many degrees would the temperature of the water increase?
The waste is more radioactive than the source material so why is it considered waste? If the waste could be use to create a bomb it stands to reason it could be used to boil; water, green house gases or maybe even noble gases.
1) high heat means it needs to be actively cooled. and that bad thing would most likely happen if you would not do that.
3) it very much depends on the capacity of a storage pool and how long the fuel is there. decay heat goes down with time. As he mentioned initially it's about 7% of total thermal energy output - that is actually A LOT. Since a typical modern reactor has over 3000MW of thermal energy output, then even 7% of it is still quite considerable. But after like 3 months it's about 1%. After a year it no longer needs to be actively cooled - being submerged in deep water pool is enough.
and after several years air cooling is enough.
Take a Fukushima Daiichi no 4 reactor - when the power went out the fuel stored inside of it was making enough heat to slowly boil the water out of the pool. After a couple of days, there was a real risk stored fuel would get exposed.
But all they did was basically to use fire engines to replenish the water and the crisis was averted.
The current generation of reactor ain't very efficient. They utilise about 1% of the total uranium energy potential. The rest is pretty much wasted.
So yes, spent fuel is very much radioactive - but it's not uranium that makes it so radioactive. The idea is simple - the faster some material decays, the shorter its half-life, the more radioactivity it emits.
Uranium and especially plutonium have a very long half-life so they do not emit that much radioactivity. It's the fission products that are responsible for this radioactivity.
Unfortunately, you can't just keep using this fuel, despite the fact it keeps emitting heat. A too high concentration of fission products makes the reaction hard to control, the reactor could become unstable - and by that unsafe.
The process of generating fission products is also eroding fuel pellets. this carries the risk of structural damage of a fuel assembly - which could release a lot of radioactivity.
@@michazajac5881 To rephrase then, we can't simply heap spent fuel and passively use its decaying heat because it's not hot enough in low quantities, and potentially explosive in high quantities?
@@beback_ i think there is a project in the Czech Republic to use spent fuel for house heating
the heat from spent fuel dies down with time - very quickly at first, then it gradually slows down over time.
spent fuel has to be actively cooled for at least the first several years - by active cooling I mean you submerge such fuel rod in a several-meter deep water pool, and then you either have to cool down the water or replenish it while it evaporates.
if you dont do that you risk rods getting exposed - water serves as both coolant and radiation shielding - so without water, you're going to have some radioactive contamination.
potentially severe contamination if rod casings get damaged for whatever reason.
after several years heat generation is small enough that such rod can be taken out of the pool and stored in so-called "dry casks" - a steel box that provides ventilation to remove any heat buildup. At this point, there is next to no maintenance needed to keep on storing this fuel for decades.
explosions are not possible. with or without cooling.
for nuclear explosion fuel just ain't anywhere close to being enriched enough
for chemical explosion temperature ain't high enough to separate water molecules into hydrogen and oxygen.
Being German, I have had problems, to understand everything. And frankly I stepped over the questions and answers at the last 4th part, because of bad phonic quality. I am wondering, why are you not mentioning new concepts of nuclear power plants, for example the MSR, LFTR or the European enhancement of these concepts: the Dual Fluid Reactor (DFR)? They are said to burn nuclear waist. Or is this idea wrong? Could somebody answer please? I know, it's rare to get answers on RUclips, but this question is bothering me since a long time now. I would be very grateful for some explications ...
my assumption is that this is a more entry level physics lecture. maybe its not even physics, but some other environmental impact class. liquid salt reactors are more complex in function, just trying to get students to understand the difference between coolant salts, inhibiter salts, and thorium/uranium duel fuels in a liquid salt state, and how all 3 work together. as for spent fuel reactors, those need to be FAST reactors, which have lower power output, and have a rise in costs. Thorium liquid salt reactors however do not need to be of the FAST reactor type, but more along the lines of LFTR reactors for high return. being in a liquid salt state, with a small amount of enriched uranium to start the breeder reaction, can cycle through all of the thorium materal, and even extract secondary byproducts, such as plutonium for NASA to be used as a heat decay power source for satelites in vaccuum, medical radioactive isotopes, a new source of rare earth materials than naturally only occur in isolated places such as volcanic areas of china. thorium salt reactors are even capable of taking the the radioactive components of coal-ash, from power plants (roughly 8-11% of coal ash is radioactive) and can be refined down and recycled as a fuel source for thorium reactors. and unlike uranium pellet reactors, which are 99.1-99.3% uranium 235 and 0.7-0.9% uranium 238 at the end of cycle, liquid salt uranium and liquid salt thorium reactors can have a much better "burn" cycle, without waste byproduct, a better recycle factor (typically only needing to add 30% more raw mass, before going back into the reactor) where as solid uranium pellets still have massive amounts of radioactive material, that is simply no longer able to release 2-3 neutrons to continue the reaction, and becomes near useless. but those pellets can be crushed, cycled, and redeployed in a liquid salt reactor with enrichment as low as 3-5% where as older pellet reactors need at least 18% enrichment to maintain a fission reaction, just with how its in a solid state and can only affect the outer pellet shell, thanks to the medium barrier between the rods themsevles. (but this is from a knuckle dragging caveman with limited understanding so take my explanation with a grain of doubt to accuracy) I will say Canada is investing in LFTR reactors by the same engineering team who has built our CANDU reactors, but for the province of New Brunswick, with tons of information about them going up and running by 2032. one of which will have the function of using thorium, with an enriched uranium catalyst, the other will be repurposing old depleted uranium in a liquid salt reactor.
@Marek Stepanek.
Was sind eigentlich die Spaltproduke dieser modernen Reaktoren, die nur wenige hundert Jahre endgelagert werden müssen?
Davon wird zwar immer viel erzählt, aber bisher ist noch keiner mit harten Fakten herausgenommen.
I felt home when he asked why we recycle as a german to be fair. :P
Hey let’s put the waste in the great pyramids of Egypt 🇪🇬
Why
Y tho
Genius! 🙄 what why like 🤦
ruclips.net/video/FYbavuReVF4/видео.html
Smarter to isolate the waste into stable frit, use the heat of decay for something useful.
"Cost effective" ... heh. Unfortunately, that's the problem with recycling - it's monetary cost is high.
Compared to what? Cost of doing nothing? Cost of scaring the public that there is no solution and therefore we forego nuclear power? Cost of ridiculously overdesigned yucca mountain?
@@StevePiet I should have been more specific, I was responding to the crowd answer of "why do we recycle". In a consumer, "get rid of my trash" situation, recycling is more expensive compared to just throwing it away, monetarily speaking. Then looking at the processing, recycling is more expensive than just dropping the trash into the ground and doing nothing with it.
I am very concerned with all the electronics the world makes in such a way that is unrecoverable. Companies like Apple who make products that are designed to fail after a few years and those processors and microchips have precious and rare-earth metals that are unrecoverable right now and, I suspect, most people just trash those items.
@@StevePiet I should add, I found your presentation very informative. I watched all 4 parts. And I learned a lot that I didn't know about the recycling of our nuclear byproducts. I didn't realize our waste handling was such a political snafu. I had thought it was a technological limitation, which really doesn't make sense with a little bit of thought (for a person who has had a first year college chemistry and physics class).
I didn't realize it took 5 years minimum to cool those rods. That's amazing!
We don't recycle spent fuel because it is cheaper to use fresh Uranium. Leaving the spent fuel in casts is cheap.
Steve, thanks for sharing that excellent and very informative lecture. I've been involved with some aspects of UK on radioactive waste disposals for the last few decades, so it was great to discover an informed view from the USA.
What's FUKUSHIMA
Two reasons for not recycling spent fuel:1: Recycling spent fuel concentrates plutonium and that is a far bigger security risk than spent fuel. 2: Plutonium has a half life of 250 000 years. How can we guard something for several million years if humans have been around only about as long as one half life of plutonium?
Depleted uranium is not what is left when spent fuel is removed from a reactor, it is the uranium 238 that is left at the end of the enrichment process.
Plutonium can be used in mixed-oxide fuels (MOX) and be safely consumed and turned into fission products. Also the Pu produced in comercial LWRs isnt weapon-grade, because it contains a mix of other isotopes, like Pu-238, Pu-240, Pu-241 and Pu-242 if remember correctly. If you remove Pu, U , and the other transuranics, you can use them as MOX fuel, The fission products left behind would decay below the original ore natural radiation levels in just 300-500 years (dependingn on who you ask), wich is far better than the 10000+ years with the Transuranics still there.
renew clear
So quick question the transuranics are they the only toxic part
Yes and no. The moment the spent fuel comes out, it contains highly radioactive, but short lived isotopes of various elements (short lived and highly radioactive go hand in hand). These decay down over time, and by the ~10 years of sitting in a cooling pond on site of the nuclear plant, most of it has decayed away. At this point there is a small number of remaining radioactive isotopes, but they decay slower and are less radioactive. On top of that though is the plutonium (a transuranic), and this is where people get upset - Pu239 has a ~24,000 year half life. If you wait 240,000 years, that is 10 half lives or 1/(2^10 ) or about a thousandth of it left over. However, Pu239 (and other Pu isotopes) contain stored energy. Rather than waiting for their decay, it makes far more sense to consume them in next generation reactors, or separate out the Pu and mix it for use in current reactors. It changes a waste to a resource. In addition, this video points out that additional neutrons can be used on the "unburned" uranium (238) turning it into Pu for use to generate even more energy. Note that your question is a bit ambiguous, "toxic" could refer to radioactivity as well as chemical toxicity. For example, arsenic could be radioactive, but it is also known to be toxic even if not radioactive.
LFTRnow thanks that’s that was exactly what I meant by toxic both the radioactiveness and chemical toxicity. another quick question most of the nuclear reactors use the little pellet in stacks of lots of pellets but would it be possible to run stuff on small version like a car (I know dangerous) or and exoskeleton suit as the energy thanks again for all the info
@@Eddievargas1 I think you are asking if you could make a small portable reactor? The reality is that nuclear energy produces high energy neutrons which are dangerous and can penetrate significant distances. This limits the safe size of any reactor due to the need for shielding. In addition to that, an appropriate reactor should also have additional space used for things like emergency cooling, etc. Finally, laws basically prohibit consumer nuclear reactors (I know, darn ) :) In any case, there is another problem - unless you have highly enriched uranium, you need a physically large reactor in order to get enough reactions out of the neutrons generated in order to have a stable reactor - by stable, I don't mean it could explode - I mean not enough fissions per time will happen and it will just sit cold.
LFTRnow thanks for the quick reply and by no means do I have any understanding of this stuff but it would seem from watch I’ve watch on youtube (out of curiosity) that we could probably do it the weight in my situation almost doesn’t matter and if the reaction chamber alone with the small about of fuel was very small with insulated tube coming out then a sort of Russian nesting dolls made of lead(or if there’s a better alloy or something) and water filling each individual compartment. Hahaha and yeah all this is just me dreaming
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Remember, toxic and radioactive aren’t the same things. Not everything that’s toxic is radioactive, and not everything radioactive is toxic.
Dirty, dirty, dirty, $, $, $
Why not?
Well cuz I remember reading it created weapon grade nuclear plutonium as a by product.
And you wouldn't want that all over the world now would you.
Cringe hahaha
Luke 6:42 How can you say to your brother, ‘Brother, let me take out the speck that is in your eye,’ when you yourself do not see the log that is in your own eye? You hypocrite, first take the log out of your own eye, and then you will see clearly to take out the speck that is in your brother’s eye.
So typical of Americans to tell the world how to deal with their business and call for sanctions when they themselves can’t deal with their own problems. Or is it because of that that bark so loud and point fingers elsewhere to direct attention away from their own wrongdoing???
This is a video about nuclear fuel recycling, what does this have to be political ?
@@NnPpCc unfortunately it is the politicians that make policy and who decide on actions to be taken. American policy is to create political instability everywhere they can so they can exploit such situations and sell arms, make deals for cheaper resources and place puppets in power that will play their will. Anything to make a buck and a stronger dollar…
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