Is there information on why precisely the BWRX-300 reactor shaft grew so immensely?
Small reactor economics are especially sensitive to safety requirements. The best chance for small containment sizes to fully use the modular and small (!) idea without regulatory easing will be atmospheric pressure reactors: Liquid metal (especially lead) and molten salt reactors. Gas cooled graphite moderated reactors probably not so much. From what we have seen from LWR SMRs so far (AP300, BWRX-300, Nuscale), the containment building effort is just too big.
In my humble opinion, Nuscale is dead except for subsidized export projects. Best case, they can reuse the integrated power module with a different building/containment design and relaxed regulation in the future.
The FAA has different safety standards depending on the aircraft size and purpose. A good example for the NRC.
So from the podcast episode it seems like they just tried to slim all the safety systems down to one of everything and the NRC wasn’t happy with that. Before you now it it bulked up.
I think the lesson here is to have very good front-loaded communication with your regulators for what would be acceptable. I think in this case they thought passive-everything ought to earn them the right to shed a lot more safety systems than it ultimately did.
The nuscale module itself is fantastic. It’s still very viable if someone can find a creative way to ditch the pool. I think there’s a startup…might be called Blue something that is actually looking to put them offshore! Right in the biggest pool of all…the ocean!
Do you have an opinion on which "atmospheric pressure reactors with reasonable power density, e.g. liquid metal (especially lead) and molten salt reactors" design will come out on top?
Since not even prototypes are running (in recent history) of most designs/technologies and NRC regulatory reform is ongoing, not really.
Lead cooled fast reactors and molten salt reactors with liquid fuel are very promising in theory. If they can be commercialized in reasonable time, I expect much of them.
The problem with lead-cooled (or anything but water cooled really but especially with hot metal) is it sounds like hell if it ever springs a leak. Which you know it will.
In pool type reactors, lead will be only used in the primary loop/pool. A leak of the primary loop is a problem in an LWR as much as in a LFR. And in an LWR, your coolant also is under high pressure and evaporates.
I don't believe that there is a major difference to be honest.
Maintenance is more difficult though because you can't cool the lead down or see through it easily.
I recently read (I think it was from the IAEA) that there are about 70 SMR designs competing globally, but that there is movement seeking standardization. Amazon has made a big commitment to x-Energy's advanced SMR which uses TRISO-x fuel. Do you think they've made a wise choice? Or would you have chosen another type SMR design?
The cool thing about TRISO which I previously wrote about is the NRC really have accepted it as an alternative to containment. That is, the silicon carbide shell is deemed to contain the fission products so well that they are considered safe in the case of an accident to keep everything in.
This gets you…a lot. No need for a containment building. No worries about aircraft impact.
What does it cost? Unfortunately also a heck of a lot…the most expensive nuclear fuel we have.
Is there information on why precisely the BWRX-300 reactor shaft grew so immensely?
Small reactor economics are especially sensitive to safety requirements. The best chance for small containment sizes to fully use the modular and small (!) idea without regulatory easing will be atmospheric pressure reactors: Liquid metal (especially lead) and molten salt reactors. Gas cooled graphite moderated reactors probably not so much. From what we have seen from LWR SMRs so far (AP300, BWRX-300, Nuscale), the containment building effort is just too big.
In my humble opinion, Nuscale is dead except for subsidized export projects. Best case, they can reuse the integrated power module with a different building/containment design and relaxed regulation in the future.
The FAA has different safety standards depending on the aircraft size and purpose. A good example for the NRC.
Have a look at this:
https://www.elidourado.com/p/personal-aviation
So from the podcast episode it seems like they just tried to slim all the safety systems down to one of everything and the NRC wasn’t happy with that. Before you now it it bulked up.
I think the lesson here is to have very good front-loaded communication with your regulators for what would be acceptable. I think in this case they thought passive-everything ought to earn them the right to shed a lot more safety systems than it ultimately did.
The nuscale module itself is fantastic. It’s still very viable if someone can find a creative way to ditch the pool. I think there’s a startup…might be called Blue something that is actually looking to put them offshore! Right in the biggest pool of all…the ocean!
Do you have an opinion on which "atmospheric pressure reactors with reasonable power density, e.g. liquid metal (especially lead) and molten salt reactors" design will come out on top?
Since not even prototypes are running (in recent history) of most designs/technologies and NRC regulatory reform is ongoing, not really.
Lead cooled fast reactors and molten salt reactors with liquid fuel are very promising in theory. If they can be commercialized in reasonable time, I expect much of them.
The problem with lead-cooled (or anything but water cooled really but especially with hot metal) is it sounds like hell if it ever springs a leak. Which you know it will.
In pool type reactors, lead will be only used in the primary loop/pool. A leak of the primary loop is a problem in an LWR as much as in a LFR. And in an LWR, your coolant also is under high pressure and evaporates.
I don't believe that there is a major difference to be honest.
Maintenance is more difficult though because you can't cool the lead down or see through it easily.
I recently read (I think it was from the IAEA) that there are about 70 SMR designs competing globally, but that there is movement seeking standardization. Amazon has made a big commitment to x-Energy's advanced SMR which uses TRISO-x fuel. Do you think they've made a wise choice? Or would you have chosen another type SMR design?
The cool thing about TRISO which I previously wrote about is the NRC really have accepted it as an alternative to containment. That is, the silicon carbide shell is deemed to contain the fission products so well that they are considered safe in the case of an accident to keep everything in.
This gets you…a lot. No need for a containment building. No worries about aircraft impact.
What does it cost? Unfortunately also a heck of a lot…the most expensive nuclear fuel we have.