5 ms·

Because of either ignoring, willfully or otherwise, scaling laws. The relationship between price and size of most plants takes the form of: Price(size) = fixed

Because of either ignoring, willfully or otherwise, scaling laws. The relationship between price and size of most plants takes the form of: Price(size) = fixed + K*size^b Where b is almost always less than 1, can go as low as 0.6. So building 6 small reactors will be more expensive than building a single reactor 6 times the size. This is the difference between vertically scaling (bigger thing) vs horizontal scaling (multiple smaller things). Horizontal scaling will almost always cost you more.

DanielVZ 3y ago
But at the same time horizontal scaling is more elastic; and depending on how demand behaves, elasticity can result in less cost.
fulafel 3y ago
The EPR seems to disprove this.
- raphaelj 3y ago
  Actually quite the opposite. The EPR cost less per GW than what was announced for these.
  - deleted 3y ago
    [deleted]
  - fulafel 3y ago
    EPR disproves it because it costs same or more per GW than smaller (eg AP1000) plants, comparing actual finished plants.
thesnide 3y ago
yet, microservices are all the rage now. It makes sense when the monolith is very complex to certify, so having discrete parts that are individually certified is more expensive only in theory when you dont factor in the exponential certification complexity. which i guess is high for nuclear related parts.
- _aavaa_ 3y ago
  Except this doesn’t actually decrease the complexity of each mini reactor. You still have all the same parts in each one, plus you pay a premium for losing scale.
  - natmaka 3y ago
    It only fully plays on locally, under a unique (national) certification authority. Historically each nation nuclear certification authority developed its own set of requirements. There are links, and a push to federate efforts, however it remains true. Case in point: the Olkiluoto-3 EPR reactor isn't exactly the same as Flamanville-3, the one being built in France, because the Finns wanted/needed various different thingies. Any of such requirement may have a significant impact on the design, and therefore impede the SMR approach.
credit_guy 3y ago
Your equation is correct except when it's not. We build so few gigawatt-size reactors. In the US only 4 came online since 1990. For most of the construction crew of such a reactor, that job is the first of that type in their career, and the last. They get trained on the job, and that (ultra-expensive) training is then never used again. Contrast that with the building of naval reactors, which are essentially SMRs. The US builds about 1 or 2 per year. In factories. The workers there participate in the building of numerous reactors during their careers. For each reactor, the majority of the crew has already done the job at least once before, and they know they will continue using their skills for many years to come. The cost of naval reactors is classified, but one could infer from this congressional report ([1], page 6) that an A1B reactor cost about $400 MM in 2011 money. Adjusted for inflation, that would be $560 MM today. A single A1B reactor is equivalent to about 3 NuScale modules, so 2 A1Bs would be equivalent to the 6-module package that was canceled here, because its cost ballooned to more than 9 billion. The US Navy is able to procure them for less than $1.2 BN. So, no, the economics don't fundamentally doom SMRs. It's just that you can expect the numbers to start working out only after you enter serial production. The first-of-its-kind costs are always high. [1] https://www.cbo.gov/sites/default/files/112th-congress-2011-2012/reports/05-12-nuclearpropulsion.pdf https://www.cbo.gov/sites/default/files/112th-congress-2011-...
- _aavaa_ 3y ago
  > For most of the construction crew of such a reactor, that job is the first of that type in their career, and the last. They get trained on the job, and that (ultra-expensive) training is then never used again. I am not disagreeing with the idea of Wright's law. The US Navy very likely benefits from it, but NuScale does not, and possibly never will. However, a) this does include other prices such site licenses and environmental assessment. b) Wrights law models a decrease with every doubling in units produced. At 1-2 a year, we're looking at a very long time to get several doublings in. NuScale meanwhile has 0 doublings under their belt. And NuScale is not alone in this field, there are dozens of companies, each one promising the same thing (SMNRs). The Navy has a single source for their reactors, NuScale has lots of competition and has to share the market, leading each of company to get even fewer reactors built per year. c) Someone has to pay those early costs. For the Navy, there are not many alternatives; there are no PV or Wind aircraft carriers. It's nuclear or oil. The same is not true about power generation. d) As you say, each navy reactor is about 3 NuScale modules. Why does the Navy not build 3 smaller modules and get even better scaling? Why not 30? I argue they don't because of the costs associated with horizontal scaling. NuScale meanwhile doesn't have a power budget they need to hit, they are trying to produce baseload power, and the bigger they make them the more economies of scale the nuclear reactor benefits from.

DanielVZ 3y ago

But at the same time horizontal scaling is more elastic; and depending on how demand behaves, elasticity can result in less cost.

fulafel 3y ago

The EPR seems to disprove this.

raphaelj 3y ago
Actually quite the opposite. The EPR cost less per GW than what was announced for these.
- deleted 3y ago
  [deleted]
- fulafel 3y ago
  EPR disproves it because it costs same or more per GW than smaller (eg AP1000) plants, comparing actual finished plants.

thesnide 3y ago

yet, microservices are all the rage now. It makes sense when the monolith is very complex to certify, so having discrete parts that are individually certified is more expensive only in theory when you dont factor in the exponential certification complexity. which i guess is high for nuclear related parts.

_aavaa_ 3y ago
Except this doesn’t actually decrease the complexity of each mini reactor. You still have all the same parts in each one, plus you pay a premium for losing scale.
- natmaka 3y ago
  It only fully plays on locally, under a unique (national) certification authority. Historically each nation nuclear certification authority developed its own set of requirements. There are links, and a push to federate efforts, however it remains true. Case in point: the Olkiluoto-3 EPR reactor isn't exactly the same as Flamanville-3, the one being built in France, because the Finns wanted/needed various different thingies. Any of such requirement may have a significant impact on the design, and therefore impede the SMR approach.

credit_guy 3y ago

Your equation is correct except when it's not. We build so few gigawatt-size reactors. In the US only 4 came online since 1990. For most of the construction crew of such a reactor, that job is the first of that type in their career, and the last. They get trained on the job, and that (ultra-expensive) training is then never used again. Contrast that with the building of naval reactors, which are essentially SMRs. The US builds about 1 or 2 per year. In factories. The workers there participate in the building of numerous reactors during their careers. For each reactor, the majority of the crew has already done the job at least once before, and they know they will continue using their skills for many years to come. The cost of naval reactors is classified, but one could infer from this congressional report ([1], page 6) that an A1B reactor cost about $400 MM in 2011 money. Adjusted for inflation, that would be $560 MM today. A single A1B reactor is equivalent to about 3 NuScale modules, so 2 A1Bs would be equivalent to the 6-module package that was canceled here, because its cost ballooned to more than 9 billion. The US Navy is able to procure them for less than $1.2 BN. So, no, the economics don't fundamentally doom SMRs. It's just that you can expect the numbers to start working out only after you enter serial production. The first-of-its-kind costs are always high. [1] https://www.cbo.gov/sites/default/files/112th-congress-2011-2012/reports/05-12-nuclearpropulsion.pdf https://www.cbo.gov/sites/default/files/112th-congress-2011-...

_aavaa_ 3y ago
> For most of the construction crew of such a reactor, that job is the first of that type in their career, and the last. They get trained on the job, and that (ultra-expensive) training is then never used again. I am not disagreeing with the idea of Wright's law. The US Navy very likely benefits from it, but NuScale does not, and possibly never will. However, a) this does include other prices such site licenses and environmental assessment. b) Wrights law models a decrease with every doubling in units produced. At 1-2 a year, we're looking at a very long time to get several doublings in. NuScale meanwhile has 0 doublings under their belt. And NuScale is not alone in this field, there are dozens of companies, each one promising the same thing (SMNRs). The Navy has a single source for their reactors, NuScale has lots of competition and has to share the market, leading each of company to get even fewer reactors built per year. c) Someone has to pay those early costs. For the Navy, there are not many alternatives; there are no PV or Wind aircraft carriers. It's nuclear or oil. The same is not true about power generation. d) As you say, each navy reactor is about 3 NuScale modules. Why does the Navy not build 3 smaller modules and get even better scaling? Why not 30? I argue they don't because of the costs associated with horizontal scaling. NuScale meanwhile doesn't have a power budget they need to hit, they are trying to produce baseload power, and the bigger they make them the more economies of scale the nuclear reactor benefits from.