4 ms·

And monkeys might come flying out of my butt except in our post enlightenment world we need facts, observations, and reasoned evidence to support claims. Molte

And monkeys might come flying out of my butt except in our post enlightenment world we need facts, observations, and reasoned evidence to support claims. Molten salt reactors have so far proven extremely difficult to build and operate and tend to leak molten salt. Fast reactors are mostly not a thing at this point. Making complex technologies work means not only overcoming technical challenges but doing so in a way that constrains both costs and risks which so far has proven to be extremely difficult.

darkpuma 7y ago
We'll soon find out. China is reportedly spending quite a lot of money trying out LFTR reactors.
nickik 7y ago
> proven extremely difficult to build and operate and tend to leak molten salt 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 https://www.youtube.com/watch?v=p1lkDRX2huM
- shereadsthenews 7y ago
  You can't wave away the remaining challenges of a molten salt reactor. It is a legitimately difficult materials science problem to operate a liquid salt pump loop operating at ~1000K and under high neutron flux. 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.
  - nickik 7y ago
    I don't wave anything away. My point is there are not fundamental challenges. Its a large expensive engineering project, but you don't need any miracles. We built a working molten salt reactor with 9m and 30 people and they built it in 4 years and then operated it for 10-15 years in the 60-70s. Not Magic. > 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.
ryacko 7y ago
Nuclear waste produced per person is on the order of kilograms versus the volume and mass of carbon dioxide which is in the tonnes. 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.

darkpuma 7y ago

We'll soon find out. China is reportedly spending quite a lot of money trying out LFTR reactors.

nickik 7y ago

> proven extremely difficult to build and operate and tend to leak molten salt 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 https://www.youtube.com/watch?v=p1lkDRX2huM

shereadsthenews 7y ago
You can't wave away the remaining challenges of a molten salt reactor. It is a legitimately difficult materials science problem to operate a liquid salt pump loop operating at ~1000K and under high neutron flux. 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.
- nickik 7y ago
  I don't wave anything away. My point is there are not fundamental challenges. Its a large expensive engineering project, but you don't need any miracles. We built a working molten salt reactor with 9m and 30 people and they built it in 4 years and then operated it for 10-15 years in the 60-70s. Not Magic. > 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.

ryacko 7y ago

Nuclear waste produced per person is on the order of kilograms versus the volume and mass of carbon dioxide which is in the tonnes. 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.