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Evanish
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This is a question about average light water reactors. I was wondering when the total becquerels of a spent fuel rod would equal the becquerels of that same fuel rod before it was used.
Evanish said:This is a question about average light water reactors. I was wondering when the total becquerels of a spent fuel rod would equal the becquerels of that same fuel rod before it was used.
Most fuel batches these days average about 4% for BWR fuel and 4.5-4.9% for PWR fuel, with peak enrichments in fuel rods in the active zone of 4.9% in BWR fuel and 4.95% in PWR fuel (most designs use axial blankets. BWR fuel tends to use natural enrichment, while PWR fuel uses slightly enriched UO2). Discharge burnups are around 50 to 60 GWd/tU rod average.Simon Bridge said:Note: The "Becquerel" is a unit ... you want to ask a question about "radioactivity".
Light water reactors use U235 enriched to 3% ... it's not very radioactive.
Spent fuel rods are mostly U238, with a little of the U235 left - and Pu.
Back of envelope - it would be the time for almost all the Pu to decay: roughly: 400,000yr ...
"huge" is a comparative term, when you use it you need to say what you are comparing it to.Dream Relics said:It seems to me that the production of the radioactive waste material from nuclear reactors is a huge serious drawback to the use of nuclear power to generate electricity.
... where online? Online sources vary considerably in their reliability.I looked it up somewhere on line...
... when? Have you not checked since? How was the search relevant to the discussion?... once...
That would be a personal reaction. What were "the numbers" in question? What is it about them that you find "staggering"?... as to how many reactors there are and how much waste each one produces per year and the numbers were quite staggering.
Is that the reality? How do you know? It seems that nuclear engineers think they do have clever and safe ways to store nuclear waste. Maybe these are not "truly" clever or safe, but how is that not a "no true scotsman" fallacy?Couple that with the reality that we have not yet any truly safe or clever way to store or dispose of that waste and it seems like the benefits we are deriving from the fuel cost situation are far outweighed by this huge insane mess of nuclear waste we are ending up with.
Technically that is not a question, but it can be treated as one. The short answer is "no".I am wondering if anyone has any ideas to how we might speed up the decay time of nuclear waste, for one thing.
There is zero chance that chemical bonding will affect the nuclear processes.... or what are the chances that the material could be bounded with some other elements to create something that was stable and no longer throwing off electrons(or beta or alpha or gamma, whatever the case may be).
There are useful things that can be done with nuclear waste. The americium used in smoke detectors are a form of nuclear waste for example. Plutonium, which is a byproduct of Uranium reactors, is used to generate more power in plutonium reactors.Or why isn't there anything useful we can do with that radioactive material? Okay - while writing this I did some googling. Apparently there are people working on batteries that run off of radioactivity. but right now they are high cost and low efficiency.
No. That is what is happening naturally in radioactive decay - the unstable element is turning, by stages, into a more stable element. It is technically possible to turn a waste product into another radioactive substance which decays faster but there is no "magic" path to go "zap" you're safe. Besides, the stable end product of most radioactive waste decay is lead, which has it's own issues.Or perhaps this is more in the realm of old fashion alchemy. But what if we could break the radioactive waste down into simpler more stable elements? Or is that completely beyond any capability we have?
That would be nice. As it happens, we have a lot of alternatives to nuclear power, each with their own issues.In any case it does really seem like we are in desperate need to come up with something far more clever than the nuclear power plant as a way of generating electricity.
No it isn't. There was a time when electricity was not used at all for energy ... wind and water power was used directly to drive machines (along with animal strength), and fire was used for heat and light. However, the modern world depends on electricity....and this may be a stupid question. But is electricity itself the sole and only form of natural phenomena which can be made to power machines and lights and everything?
Yes. That would be a reasonable projection into the future from present knowledge.Even if some previously unknown power source were discovered, there will still be some use in using electricity just like we still use water wheels, animals, gas etc directly to do some things. ie. people still use horses for transport in someplaces.Are we always going to be using it and finding ways to make it?
It is unlikely that there would be a hitherto unknown and unsuspected physical process that would also be a plug-in replacement for electricity. To work as electricity does, it would have to be electricity.Or is there perhaps some other force, method, thing, that we might hit upon to run machines and everything, that does what electricity does but that is somehow completely different?
Electricity is a branch of applied electromagnetism. Electromagnetism is a fundamental force of Nature. However, there arelots of other ways to run cars and computers and such stuff - we currently build a lot of stuff out of electrical components because that's cheap and convenient to do but we don't have to. ie. we don't need to build observatories using cctv optics: in the past we used ground glass and metal or wood and before that we used great huge slabs of rock. It is possible to make a gravity driven computer out of ramps and balls.Or is electricity so basic and intrinsic to the physical world that it is in fact what we are stuck with forever as a mechanism for running computers and cars and radios and all the crazy things we build and use that run on electricty
I don't know what you mean by that. What would something need to be able to do to be "like electricity" in the sense you mean?I don't even know what the proper term might be. force? power? is electricity the only thing like itself in nature?
Technically all elements besides hydrogen is the byproduct of nuclear processes occurring long ago. I don't know that it is generally held that all the lead on the Earth comes from nuclear decay from after the formationof the Earth. However, for eg, about half the Uranium at the formation of the Earth would be lead now.As to the point about speeding up the decay or rendering it into something more stable. Right I know it all turns into lead eventually. I suppose we might assume that all the lead on our planet is the remnants of radioactive materials from long ago.
The general rule is that the heavier the element, the more unstable it is. To make a lump of plutonium more stable you have to break it apart. You could, technically, force it to fission into a bunch of helium and hydrogen atoms and that would be stable. However, the energy needed to make that happen is bigger than what you'd get from the original process that made the plutonium.So I wonder if uranium or plutonium or whatever the atomic waste is, since its problem is that the atoms are unstable I am envisioning a process where an unstable heavy element can be brought together with the right lighter element and create a fusion that sucks off the radioactive bits and makes the lighter element into one up the chain a little ways.
... sort of. But like any puzzle, you have to obey the rules when you fit the bits together or take them apart. You need a physical process to achieve the results. It takes time and energy to make stuff happen.After all, are not all the elements just sort of like puzzle pieces of the more basic elements joined together?
No. Nothing like that.Doesn't the instability create a sort of opening into which we might be able to add the necessary bits to make the element stable or something like that?
Define "primitive"? Electricity is a fundamental process, more fundamental than, say, a horse walking and pulling something....as to the point about electricity. All the other examples you mention of things that accomplish work are more primitive.
What you described is a force that is exactly like electricity ... in which case, it actually is electricity. If you have an object that looks like a duck, it acts like a duck, and is ever bit like a duck in all ways ... it's a duck. You may assert it is not, in fact, a duck - but if there is no way to tell the difference between it and a duck, it's a duck. This is a basic principle that saves a lot of effort.What I was getting at is whether or not there was another fundamental force like electricity that could run through wires, power lights, generate heat, like basically be the basis for higher technology the same way that we use electricity. But i am guessing the answer is no.
Right now we know of four distinguishable forces (electricity is not a force btw, it is the label given a group of phenomena) - these are electromagnetic, gravitational, strong nuclear and weak nuclear forces.I suppose it is a silly question and one that verges on fantastic science fiction kinds of notions, it is just that at the moment when the question occurred to me I was really struck by the realization of how basic and unique electricity is. I suppose the fact that it works the way it does is because everything has electrons in it.
I find that unlikely ... it is basic High School textbook stuff. See also:Dream Relics said:hmm' I don't know that I have come across anyone asserting that gravity was part of the electromagnetic force/phenomenon.
Define "insight". We have as much understanding of gravity as we do any fundamental force. Though you should know that we do not strictly have a cause for any fundamental force - that's why it is fundamental. But if charges and charge density can be thought of as the cause of electromagnetic force then mass and energy density is equally the cause of gravitational interactions. What else did you have in mind?I though gravity was something that we still don't have a great deal of insight into exactly what it is or what causes it.
There are still many mysteries to physics as a whole but we know a lot about gravity.Lots of data on what it does. and I guess curved space time is one explanation of sorts about gravity. But I was under the impression that there were still many mysteries to it.
Nothing is "fully explained", but we do know more than you seem to think.Electromagnetism is very interesting. As I understand it, they are related, but they do have some differences that are not fully explained.
Irrelevant - heads and tails don't have all the same properties as each other either but they are both part of the same coin. The unification of electricity and magnetism is an established fact of physics established in print by Faraday and Maxwel. Since them there have been confirmation in the relativistic and quantum mechanical pictures.Electricity creates magnetic fields, and magnets can create electricity. but they don't have all the same properties as each other. For instance there is no such thing as a monopole magnet.
Where? Honestly, are you paying attention to what I tell you? Use citations.I read ...
The clue is in the name: "dynamo". Dynamo's work at any temperature while solid permanent magnets can lose their magnetism when their magnetic domains go into disarray, ie when they get shaken up too much....that at least with manufactured magnets that high temperatures can cause them to loose their magnetism. If that is so, I never quite understood how the molten dynamo of the Earth's core could be generating the Earth's magnetic field.
"Fundamental" not "basic" ... and it's the other way around: the classica forces do not "have influences and interactions and causes that are at the quantum level", rather, the classical forces are an emergent phenomenon of the underlying QM interactions. At the quantum level the idea of causation gets tricky, see also:It does rather seem like the four basic forces and maybe many of the larger observed phenomenon must have influences and interactions and causes that are at the quantum level.
String Theory is a whole other kettle of piranhas. You are having enough trouble dealing with the idea of the fundamental forces. Try just sticking to the standard model.All those vibrating strings and so forth.
Becquerel is a unit of measurement for radioactivity, specifically the rate at which a substance decays over time. In the context of nuclear waste, it is used to measure the amount of radiation emitted by the waste as it decays.
The becquerel of nuclear waste decreases over time as the radioactive materials in the waste decay into more stable forms. This process is known as radioactive decay and can take thousands of years for the waste to reach a safe level of radiation.
The main factors that affect the becquerel of nuclear waste over time are the type and amount of radioactive materials present in the waste, as well as the storage conditions such as temperature and exposure to air and water. The half-life of the radioactive materials also plays a significant role in determining the rate of decay.
The becquerel of nuclear waste is typically measured using specialized equipment such as a Geiger counter or a scintillation counter. These devices detect and measure the radiation emitted by the waste and provide a reading in becquerels.
High levels of becquerel in nuclear waste can pose serious health and environmental risks. Exposure to radiation can cause damage to cells and tissues, leading to various health problems including cancer. It can also contaminate the environment and harm wildlife. Proper handling and disposal of nuclear waste is crucial in order to minimize these risks.