4 ms·

Nuclear would need to get cheaper than current nuclear methods. How to get rid of excess complexity in regulations while still retaining good safety... I have

Nuclear would need to get cheaper than current nuclear methods. How to get rid of excess complexity in regulations while still retaining good safety... I have some ideas.

bryanlarsen 5y ago
Even with zero regulations, nuclear would still have a cost problem. Just the steam turbine part of a nuclear power plant is more expensive than renewables. Coal is uncompetitive for the same reason.
- pfdietz 5y ago
  When I see "less regulation!" talk, I want to ask "so, you're going to do away with the expensive parts, like the containment building?" If new nuclear is going to ever be plausible, it has to be some fundamentally new (like reactors with molten salts) that don't need massive containment buildings that can safely contain large volumes of steam in accidents. Such reactors will not be commercially viable soon.
  - corty 5y ago
    The containment isn't the most expensive part, the pressure vessel is. Single forged part of some magic stainless steel alloy able to withstand 300bar at 500K and high neutron flux costing a billion or more. Gen4 reactor designs try to do without that by having the actual core non-pressurized, e.g. in molten-salt reactors or pebble-bed reactors. The other idea is making a loss-of-coolant-accident harmless, thereby getting rid of the necessity to have too many redundant ultra-expensive cooling systems (current EPRs are at quadruple-redundant...). The problem with regulation there is that those novel designs are currently still regulated based upon the aforementioned PWR/BWR reactor designs (so your coolant system has to have X amount of redundancy, the reactor vessel must withstand Y amount of pressure, ...), forcing unnecessary cost that isn't necessary because the possible accidents and conditions are completely different.
    - pfdietz 5y ago
      > The containment isn't the most expensive part, the pressure vessel is. I was referring to the expense introduced due to regulations. Or are you saying that one could make a much cheaper pressure vessel without those pesky regulators? Gen IV reactors have the property that they aren't available now, and won't be available and matured anytime soon. Many also have aggressive operating profiles that will stress materials. No one is going to want to buy a MSR only to discover corrosion limits its lifespan to 20 years. So, getting them to a state that customers would be comfortable with will take a long time.
      - corty 5y ago
        Gen4 reactors are an active area of research, but it isn't like there are none. Some concepts go back decades, as do prototypes like THTR-300 that actually produced power for a few years. That stress will limit the lifetime of a reactor is true for any reactor. Any BWR or PWR has a maximum lifetime set by the pressure vessel, because that is the one single component you can neither fix nor exchange. As soon as mechanical stress, neutron embrittlement and temperature gradients have done a certain amount of damage, the plant is finished. But even for currently operating reactors, we are still exploring how long that will take exactly, by regularly checking the materials in the running reactors, because no one ran a prototype for 40 or 60 years. And you cannot compare with other models of reactors, because they are usually very different in operating parameters, materials and design. We currently do not know what a few decades of operation will do to a MSR vessel, but the point is that trying it out has been hindered for a long time by regulations that are not fit for that type of reactor. So you arrive at a costly chicken and egg problem, where a regulator asks for a proof (ideally a proof by pointing at a working prototype with a few decades of maturity) just to allow you building a prototype.
        pfdietz 5y ago
        THTR-300 is an example why there's a large gap between concept and commercially proven reactor design. The THTR-300 was a huge disappointment, with major, showstopping design flaws. The Gen IV concepts being bandied about now will have to go through a long, drawn out process of technical maturation before any large scale deployment can occur.
  - Gravityloss 5y ago
    No, you're putting words in my mouth. Safety could be actually improved by doing more efficient regulation.
- throwaway210222 5y ago
  > Just the steam turbine part of a nuclear power plant is more expensive than renewable If you are building a new nuclear plant to target the Rankine steam cycle at a lousy ~140°C inside an enourmous concrete bomb, you are doing it wrong. The cool kids are targeting the Brayton cycle at ~700°C and atmospheric pressure. https://en.wikipedia.org/wiki/TMSR-LF1 https://en.wikipedia.org/wiki/TMSR-LF1
- nickik 5y ago
  This is not a great way to look at it. Modern nuclear wouldn't use the kind of steam turbines that are currently used. It would either use the same turbines gas plants. Some concepts use even more modern turbines but those are not commercially proven. However if there was serious commitment to nuclear, these things would be sensible to develop also. Your overall point is well taken, nuclear is better when running at full capacity, even if I would argue that with a modern reactor with less operational cost this would be less of an issue. That however is exactly why many nuclear plants in planning today will actually heat up molten salt and use that to drive the turbine. So there is basically a built in flexible heat battery. The idea of most modern approaches is actually to have more generation power then the reactor actually provides, and have a heat battery containing in between. This makes sense as you have to have a salt loop anyways, so adding a larger tank isn't really a big extra cost. Additionally it means that the nuclear build of your project is actually a smaller % of the cost with everything outside of the nuclear boundary being pretty standard salt loops and turbines. So you might build a 500MW nuclear plant with 1.5GW turbines plus a big tank full of salt. All the turbines and the salt tank have essentially nothing to do with nuclear or nuclear regulation. However if we had started to seriously consider this in the 60s/70s/80s, establishing wind and solar would never even have made any sense outside of some niches. You build nuclear plants that can load follow without issue and accept the capacity problem. Clever engineers and business people would have soon realized that the salt loop can double as a heat battery. The problem is simply that all these issues were not seriously considered in the past. Basically the Navy wanted PWR for submarines, because those got so much development the largest contractors and the government picked it up for civilian power. Once all the large nuclear companies had bought in to that, they no longer want lots of research on other types of reactors, so not even the nuclear industry advocated for such projects. Combine that with the general turning against nuclear and you basically get massive stagnation. Unfortunately all the Molten Salt based nuclear work was done in Tennessee, a place that was not very relevant politically. There is even a famous call where Nixon basically says, moves all that potential money to projects in California.

Nuclear would need to get cheaper than current nuclear methods. How to get rid of excess complexity in regulations while still retaining good safety... I have some ideas.

bryanlarsen 5y ago

Even with zero regulations, nuclear would still have a cost problem. Just the steam turbine part of a nuclear power plant is more expensive than renewables. Coal is uncompetitive for the same reason.

pfdietz 5y ago
When I see "less regulation!" talk, I want to ask "so, you're going to do away with the expensive parts, like the containment building?" If new nuclear is going to ever be plausible, it has to be some fundamentally new (like reactors with molten salts) that don't need massive containment buildings that can safely contain large volumes of steam in accidents. Such reactors will not be commercially viable soon.
- corty 5y ago
  The containment isn't the most expensive part, the pressure vessel is. Single forged part of some magic stainless steel alloy able to withstand 300bar at 500K and high neutron flux costing a billion or more. Gen4 reactor designs try to do without that by having the actual core non-pressurized, e.g. in molten-salt reactors or pebble-bed reactors. The other idea is making a loss-of-coolant-accident harmless, thereby getting rid of the necessity to have too many redundant ultra-expensive cooling systems (current EPRs are at quadruple-redundant...). The problem with regulation there is that those novel designs are currently still regulated based upon the aforementioned PWR/BWR reactor designs (so your coolant system has to have X amount of redundancy, the reactor vessel must withstand Y amount of pressure, ...), forcing unnecessary cost that isn't necessary because the possible accidents and conditions are completely different.
  - pfdietz 5y ago
    > The containment isn't the most expensive part, the pressure vessel is. I was referring to the expense introduced due to regulations. Or are you saying that one could make a much cheaper pressure vessel without those pesky regulators? Gen IV reactors have the property that they aren't available now, and won't be available and matured anytime soon. Many also have aggressive operating profiles that will stress materials. No one is going to want to buy a MSR only to discover corrosion limits its lifespan to 20 years. So, getting them to a state that customers would be comfortable with will take a long time.
    - corty 5y ago
      Gen4 reactors are an active area of research, but it isn't like there are none. Some concepts go back decades, as do prototypes like THTR-300 that actually produced power for a few years. That stress will limit the lifetime of a reactor is true for any reactor. Any BWR or PWR has a maximum lifetime set by the pressure vessel, because that is the one single component you can neither fix nor exchange. As soon as mechanical stress, neutron embrittlement and temperature gradients have done a certain amount of damage, the plant is finished. But even for currently operating reactors, we are still exploring how long that will take exactly, by regularly checking the materials in the running reactors, because no one ran a prototype for 40 or 60 years. And you cannot compare with other models of reactors, because they are usually very different in operating parameters, materials and design. We currently do not know what a few decades of operation will do to a MSR vessel, but the point is that trying it out has been hindered for a long time by regulations that are not fit for that type of reactor. So you arrive at a costly chicken and egg problem, where a regulator asks for a proof (ideally a proof by pointing at a working prototype with a few decades of maturity) just to allow you building a prototype.
      - pfdietz 5y ago
        THTR-300 is an example why there's a large gap between concept and commercially proven reactor design. The THTR-300 was a huge disappointment, with major, showstopping design flaws. The Gen IV concepts being bandied about now will have to go through a long, drawn out process of technical maturation before any large scale deployment can occur.
- Gravityloss 5y ago
  No, you're putting words in my mouth. Safety could be actually improved by doing more efficient regulation.
throwaway210222 5y ago
> Just the steam turbine part of a nuclear power plant is more expensive than renewable If you are building a new nuclear plant to target the Rankine steam cycle at a lousy ~140°C inside an enourmous concrete bomb, you are doing it wrong. The cool kids are targeting the Brayton cycle at ~700°C and atmospheric pressure. https://en.wikipedia.org/wiki/TMSR-LF1 https://en.wikipedia.org/wiki/TMSR-LF1
nickik 5y ago
This is not a great way to look at it. Modern nuclear wouldn't use the kind of steam turbines that are currently used. It would either use the same turbines gas plants. Some concepts use even more modern turbines but those are not commercially proven. However if there was serious commitment to nuclear, these things would be sensible to develop also. Your overall point is well taken, nuclear is better when running at full capacity, even if I would argue that with a modern reactor with less operational cost this would be less of an issue. That however is exactly why many nuclear plants in planning today will actually heat up molten salt and use that to drive the turbine. So there is basically a built in flexible heat battery. The idea of most modern approaches is actually to have more generation power then the reactor actually provides, and have a heat battery containing in between. This makes sense as you have to have a salt loop anyways, so adding a larger tank isn't really a big extra cost. Additionally it means that the nuclear build of your project is actually a smaller % of the cost with everything outside of the nuclear boundary being pretty standard salt loops and turbines. So you might build a 500MW nuclear plant with 1.5GW turbines plus a big tank full of salt. All the turbines and the salt tank have essentially nothing to do with nuclear or nuclear regulation. However if we had started to seriously consider this in the 60s/70s/80s, establishing wind and solar would never even have made any sense outside of some niches. You build nuclear plants that can load follow without issue and accept the capacity problem. Clever engineers and business people would have soon realized that the salt loop can double as a heat battery. The problem is simply that all these issues were not seriously considered in the past. Basically the Navy wanted PWR for submarines, because those got so much development the largest contractors and the government picked it up for civilian power. Once all the large nuclear companies had bought in to that, they no longer want lots of research on other types of reactors, so not even the nuclear industry advocated for such projects. Combine that with the general turning against nuclear and you basically get massive stagnation. Unfortunately all the Molten Salt based nuclear work was done in Tennessee, a place that was not very relevant politically. There is even a famous call where Nixon basically says, moves all that potential money to projects in California.