What Is Called Nuclear Waste Is Mostly Fuel for Molten Salt and Fast Reactors
nextbigfuture.com
nextbigfuture.com
It's like pretending that the liabilities represented by a huge coal ash pond are actually an asset, because if all the aluminum and silicon in the ash were purified and sold it would be worth a lot at present prices. The problem is that the cost of turning the waste into a salable product is higher than the market price. So it is still in fact a liability.
Under present and foreseeable economic and technical conditions, the asset-value of spent nuclear fuel does not exceed its liabilities.
That’s always the unspoken actual debate when it comes to nuclear energy: what’s the probability of the worst case, and how does it affect the amortized cost?
We’re terrible at doing this calculation in other areas (e.g. terrorism vs. the cost of security theater), so it’s not especially informative to talk about the status quo. Clearly, we believe it’s cheaper to just store the stuff, or we wouldn’t be doing it. With nuclear energy, the exceptions matter a lot.
This is to say that even if you place a high premium on avoiding environmental releases of radioactive materials, there is no appreciable benefit from burner reactors on a human time scale. The overall radiotoxicity inventory that needs ongoing management is nearly the same for both burners and once-through reactors for 200+ years after the fuel is done with. Further, fuel reprocessing facilities are themselves more likely to leak fission products into the environment than dry cask storage is.
But these fuel reprocessing already exist and the waste are currently already reprocessed to make MOX fuel, at least in some countries (France, UK, India, Russia and Japan).
I think it would be better to say: "This is not true in many scenarios, depending on how costs are derived"
Liabilities are very hard to determine.
We are not yet to the point of operationalizing much of this stuff very well.
Given the vast amount of latent energy in such things, it's probably worthwhile looking at how we can effectively streamline and enable safety, fully accepting the fact may be 'it's impossible'.
This is because most types of spent nuclear fuel slowly become "weapons-grade" as the short half-life isotopes decay.
Since Pu-240 has a shorter half life than Pu-239, it is technically true that the isotopic composition in spent fuel becomes more weapon-like as the fuel ages. But it is very slow because Pu-240 still has a half life in excess of 6500 years. It would take more than 13000 years for the decay of Pu-241 to improve the isotopic profile of today's power reactor plutonium to something near "weapons grade."
90% percent of uranium is not burnt, and it's fuel for MSR. Subtract the costs of movilizing the fuel, and tell me it's not worth dumping it in a MSR to be burtn almost to the 100%.
> Hybrid nuclear fusion–fission (hybrid nuclear power) is a proposed means of generating power by use of a combination of nuclear fusion and fission processes. The basic idea is to use high-energy fast neutrons from a fusion reactor to trigger fission in otherwise nonfissile fuels like U-238 or Th-232. Each neutron can trigger several fission events, multiplying the energy released by each fusion reaction hundreds of times. This would not only make fusion designs more economical in power terms, but also be able to burn fuels that were not suitable for use in conventional fission plants, even their nuclear waste.
As an extra advantage, such a reactor would be subcritical (similar to a Accelerator-driven subcritical reactor [2]) so it would never be at risk of a melt-down.
On the other hand, I'm pretty sure that such a reactor would still be a proliferation risk like fission breeder reactors.
[1] https://en.wikipedia.org/wiki/Nuclear_fusion%E2%80%93fission...
[2] https://en.wikipedia.org/wiki/Accelerator-driven_subcritical...
This is a misunderstanding of what a melt-down is. In every case we know of involving commercial reactors, fuel melt-down happened when the reactor was non-critical, completely devoid of fission.
Meltdown happens when the heat generated by decay of products produced when the reactor was critical cannot be removed fast enough, such as when a cooling system fails or coolant does not cover the fuel modules.
Any reactor with solid fuel and a high enough energy density will have a meltdown possibility, unless it is somehow using a reaction chain that precludes the production of high-activity fission products.
> In every case we know of involving commercial reactors, fuel melt-down happened when the reactor was non-critical, completely devoid of fission.
This is indeed true for Three Mile Island, Fukushima and Saint-Laurent-des-Eaux in 1969, but IIRC not for Chernobyl, and this was clearly not the case in Saint-Laurent-des-Eaux in 1980. (Yes, Saint-Laurent-des-Eaux faced two indendant meltdown events…).
More generally, as long as you're using light water as a coolant and moderator (PWR and BWR), you're likely to have negative void coefficient, which prevents fission-induced meltdown, but for other technologies, the risk exists.
However the steam explosion(s) that blew apart the reactor assembly at Chernobyl did not melt the fuel rods there although of course there may have been some localized areas of melting. The melt that created the tons of corium was due to decay heat. It occurred many hours after the power excursion and explosion(s).
This is a real risk for current reactor designs. Loss of backup power means a loss of any safe shutdown option.
It's a rare case where this is an accurate statement, because a typical nuclear power plant produces a dozen or two tons of waste per year. Take a look at this observation until it sinks in just how little waste that is.
Please be precise.
https://duckduckgo.com/?q=Fuel+Rod&t=ffsb&iax=images&ia=imag...
or
https://en.wikipedia.org/wiki/Nuclear_fuel
Anybody thougt about that?
Edit: I mean even IF used in molten salt reactors where there are no rods and therefore no cladding, what happens with the old cladding? That's not just some tinfoil where you could make hats out of it!
Also, most molten salt reactors wouldn't use fuel rod. And the ones that do would be different compared to those in PWR so reuse is unlikely.
Edit: See here https://youtu.be/TvXcoSdXYlk?t=1828
Its makes sense if you also get money to consume the waste otherwise its cheaper to go with freshly mined uranium. Or if you are interested in a fuel mix that is easier to obtain in spent fuel.
Edit: For those interested, one of the company engaged in the Canadian regulator process is proposing this:
https://youtu.be/TvXcoSdXYlk?t=1828
MSR Reprocessing - Sylvie Delpech: https://www.youtube.com/watch?v=fBEjys1SKCQ
This is a talk by the company that is furthest along the timeline of bringing molten salt to the market and he talks a little about their fuel as well (they don't do reprocessing): https://www.youtube.com/watch?v=l8QVxYrQRxA
In terms of volume its far less then with a PWR as there you have lots of other stuff in there as well. For the same amount of power, the waste from a MSR will much less and would have a better waste profile.
However beyond that, it all depends. There are many different designs, different inputs, different burn rates and so on and so on.
As long as the volume of nuclear waste is easy to manage, it is more likely we will bury nuclear waste than use it, as opposed to carbon dioxide which is far less likely to be injected into the Earth.
The only are 2 molten salt reactor ever built and neither one had a leaking problem. In fact, they would even be self sealing as the salt will cool down rapidly and seal the hole. If you have a rupture in the whole core, the spilled out salt would be captured in a pool and harden, it would be contained in the nuclear site boundary. This is the advantage of high temperature and salt. The temperature differential to the environment that the cooldown is very rapid.
Compared to PWR, the danger of a a molten salt reactor is incredibly small. There is no high pressure and steam, thus no explosion that can transport stuff like zirconium outside of the nuclear boundary.
Its also false that they have been extremely difficult to build. The Molten Salt Reactor experiment was operated and built by small time at a tiny fraction of the budget that were spent on many of the other nuclear reactors built at that time. They are far easier to build then a PWR in terms of complexity of and scale involved. The Molten Salt reactor experiment (the first ever molten salt reactor) was one of the fastest nuclear reactor was ever built.
The reason we don't have them has more to do with the history of nuclear technology. The Navy focused on PWR for ships (as makes sense=, those were commercialized with big investment of government and industry and were the most mature by far. Molten Salt reactors were in development by the Navy and were discontinued when rocket technology made nuclear bombers unneeded. After that the inventor of molten salt reactors only got a tiny amount of money to continue his research for a civilian reactor.
The big nuclear players didn't really care about building new reactor types as they had lots and lots of orders of the production designs they already had. There were only a very small number of people who were educated about what a molten salt reactor or how it worked. It required a somewhat different skill set (the inventor was a chemist) and neither government nor industry had a taste for commercialization at that moment. It didn't help that the inventor basically made himself unpopular with the regulatory agency when he claimed PWR were unsuited for civilian use.
When regulation changed because of TMI and Chernoyl the nuclear companies had their hands full with rebuilding all the plants according to new regulation to keeping the existing fleet ruining (and finishing project that were being built) and by that time the regulation had changed so that it was basically impossible for any new type of reactor to be licensed. In the US the technology was hard coded in to the regulation and made it impossible to deploy a new type of reactor in a commercial way. Since then hardly any new reactor type has been built or tested as you can not get fuel for anything beyond a tiny research scale reactor without passing full commercial regulation.
Development of pretty much all serious molten salt fuel has now moved to Canada as the regulators there have not hard coded specific technologies and the regulator investing its own resources to get threw regulation of such a reactor. In the US, you would have to pay the regulator to evaluate your design with no timeline or guarantee that would even allow it at all. Meaning you would have to design a full commercial reactor before the regulators even tell what you would need to do to convince them about the reactor. Meaning you potentially spend 10s of millions on paying the regulator before the actual regulatory process could even start, as you would have to finance the development of a regulatory framework for molten salt reactors.
Thankfully the DoE has realized this now and they are working hard at chaining their approach and congress is for once actually engaging in a bipartisan effort to improve the situation. See this talk for more information about government efforts: https://www.youtube.com/watch?v=p1lkDRX2huM
It's also not a super-great explanation that a major accident will just cause the salt to flow into the holding tank. What if the holding tank is full of water? Why would it be full of water? I don't know but the planet is absolutely filthy with water and "the basement is unexpectedly full of water" has happened to almost every building humans have ever built. These are supposed to be installed _entirely_ underground, enhancing the danger of water intrusion.
Finally there is still the challenge of continuous processing of the liquid fuel, to remove ash, add fissile materials, and separate gases. Nobody knows how to do this. Nobody has explained what to do with all the radioactive krypton etc.
But they have. There's dozens of youtube videos on MSR.
And so it's containing the fusion plasma, yet billions are poured into material research. And hastelloy N is already invented.
The data gathered on its properties would not be sufficient for a modern regulator, and such a qualification would take way to long. Also, there is not really a supplier for commercial Hastelloy N.
Their focus is on using 'regular' nuclear grade materials that have already been approved. This is THE single most important focus of those reactor design. In the choice of containment, reactor type, salt solution and so on, they all picked sub-optimal things in order to make it threw the regulator and have a existing supply chain.
> It is a legitimately difficult materials science problem to operate a liquid salt pump loop operating at ~1000K and under high neutron flux.
Depending on your reactor design your not actual pumping fuel salt itself at all. Both leading contenders use a pool type system and not LFTR type system where you have to do substantial pumping, specially not of the fuel salt. Neither system in fact pumps fuel salt that is in neutron flux at all.
Have you actually looked at the real world proposed reactors we are talking about?
> It's also not a super-great explanation that a major accident will just cause the salt to flow into the holding tank. What if the holding tank is full of water? Why would it be full of water? I don't know but the planet is absolutely filthy with water and "the basement is unexpectedly full of water" has happened to almost every building humans have ever built. These are supposed to be installed _entirely_ underground, enhancing the danger of water intrusion.
In the case of IMSR, there is 1 meter nuclear grade concrete then a thick wall of steel, then a meter of a secondary cooling salt buffer, then another thick wall of steel, then the primary reactor vessel that is another massive steel cylinder. There are no opening anywhere except from the top.
That whole thing is in a hole that is topped of heavy steel protection on top and that is in building that is safe from aircraft attack. Even if you would have contact of water with the fuel salt the water would be in contact with the top layer of the fuel salt (far less surface area then fuel tubes), that would would freeze the top layer into a solid layer and shortly after the whole reactor would essentially be one block of salt in a metal concrete box.
These reactors are also not depended on water cooling at all, meaning you can build them in the desert or wherever, you don't need to be close to water in any way shape or form. Also you don't just build these anywhere, there is a citing process that looks at these like that.
Next, there is the point that in liquid salt actually does not produce many of the same hazards as fuel pellets. There are gases inside of the solid fuel pellets that get released. In a molten salt reactor the cesium and iodine are not gases, but rather they are bound in the fuel and will not get released in gas form.
This is one of the primary reasons molten salts were proposed int he first place.
So even if you flood the building and a meteor somehow made a hole in the building and reactor containment, and then you would flood it with water that would somehow show up. And all you would achieve with this is a gigantic pool heater, as a solid block of salt sits in the bottom of a hole and produces some steam (without being a system under pressure) that didn't contain the primary dangerous gases we talk about in the 'nuclear cloud'.
The amount of highly improbable events you have to chain to even achieve any danger outside of the nuclear regulated zone borders on comical. And even then its not even close to what we saw happen in Japan.
> Finally there is still the challenge of continuous processing of the liquid fuel, to remove ash, add fissile materials, and separate gases. Nobody knows how to do this. Nobody has explained what to do with all the radioactive krypton etc.
You don't actually need continuous processing and neither company that proposes to build Molten Salt reactors are proposing that.
So again, have you actually looked at the real world proposed reactors we are talking about? You seem to think all Molten Salt reactors are LFTRs.
Beryllium has excellent properties but unless you are building a breeder are not really that essential. The primary concern for the companies working on this right now is commercialization, not peak performance. They are fine with loses and inefficiency.
You have to prove to the regulator that these salts will not be outside of the reactor boundary that takes care of both the radiation and the toxic aspect.
Moltex Energy is still in the first stage of Canadian review process, as they had to relocate from Britain to Canada. Because the British regulatory system is not really active.
There is also Flibe Energy and they actually want to use lithium fluoride (LiF) and beryllium fluoride (BeF2) salt (hence the name). But that is a much longer term project and they are not anywhere close to commercialiastion. They are also working in the US Regulatory system that is not close to being ready to even start a serious commercionalisation process right now. They are also not targeting commercial energy as their primary market.
There is also ThorCon power I don't know as much about them and they are not engadged in any Western effort for commercialisation as far as I know.
There used to be Transatomic Power, but the never wanted to use beryllium fluoride either and have open sourced their reactor design.