Thread

1. preisschild · 1790751984 · focus · HN ↗

   The BWRX-300 footprint is so large they might as well just build large nuclear power units again and get 3-4x the power

   1. nine_k · 1790754444 · focus · HN ↗

      I don't think that the footprint is the key factor. Likely the total construction cost is. A large reactor may have a better cost per kWh, averaged over decades of its lifetime, but a smaller reactor likely has a more affordable upfront cost.

      1. jillesvangurp · 1790762848 · focus · HN ↗

         The key point with small modular reactors vs. reactors like this is that construction happens in factories rather than on site. Theoretically, you might get some economies of scale from series production in a factory that is much harder to get doing bespoke construction projects. Which is why historically, nuclear projects tend to blow through their cost estimates and why having larger reactors makes that a bit more tolerable. Of course until somebody actually does this and scales to hundreds/thousands of reactors production, this is all theoretical.

         This particular reactor is already estimated at over 5 billion $ I think. That's a lot of money for just 300MW and it probably could end up being a wildly optimistic estimate as well. I think effectively much of the construction is still on site and not in a factory. Hence the need for a construction permit. So, you get all of the downsides of complex on site construction such as including high cost, permitting overhead, lots of bureaucracy, associated delays & uncertainty, etc. without the upside of actually delivering a lot of power like you would with a larger reaction. Calling it "modular" might be overstating things a bit.

         Probably cheaper, faster, and easier to just plonk down 5GW of solar, wind, or battery (or combinations of those). Especially if you calculate in the 200-300% time and dollar budget that many nuclear projects seem to end up having. Maybe this one will be different. A lot of people have a lot riding on Nuclear projects breaking this trend. But then that has been the case for decades.

         1. preisschild · 1790771857 · focus · HN ↗

            You cant make every part in the factory anyways. You need lots of on-site civil engineering, which accounts for a large chunk of the total cost.

            And many parts of large (+1GWe) reactors have also been manufactured at off-site factories and then shipped on-site by barges in the past.

            1. pfdietz · 1790776988 · focus · HN ↗

               One issue here is that the structures containing the "nuclear island" are just as expensive as that island. Containment buildings are civil construction and are not cheap.

               This suggests one should move to reactor concepts that don't need such large structures. The containment building size is dictated by the need to contain a certain volume of pressurized steam in an accident (and the requirement to contain the pressure of that steam dictates the mass of the building's structure). This is perhaps the strongest motivation for reactors cooled with molten salt.

               Alternately, allow steam to escape in an accident, after filtering. Most of the radioactivity could be captured. But this violates current rules that require no release of radioactivity for 24 hours in an accident.

               1. preisschild · 1790869079 · focus · HN ↗

                  Agreed. The less nuclear-grade concrete you need the better.

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