• davetortoise@reddthat.com
    link
    fedilink
    arrow-up
    34
    ·
    edit-2
    1 day ago

    Context: I’m currently doing a PhD in nuclear engineering

    Hard-line advocates of nuclear power usually point to its role as a ‘baseload’ generation, but this term is often misused. A lot of people use it as if it means “reliable power on demand” as opposed to wind and solar which is not (without batteries). But baseload generation generally refers to plants with unvarying output that provide the minimum energy consumption of the grid, so that other (varying output) energy sources can be turned up or down to make up the deficit.

    The “unvarying” part is very important for nuclear power. Conventional nuclear plants (PWRs/LWRs) really hate when you vary their power output. This is because varying heat and radiation flux through the fuel rod cladding causes a “racheting” effect which accelerates the swelling of fuel pellets against them leading to formation of cracks in the surface oxide, which can propagate into the bulk metal if power goes up and down too often, leading to rupture of the fuel rod cladding (which is bad). Anything below 85% power output for longer than 2 weeks is classed as extended reduced power operation (ERPO) and should be minimised - typically it is done for maintenance purposes.

    This is important because it influences how much of your energy production can actually come from nuclear. France for example generates something like 75% of its electrical power from nuclear, but this is only possible because they are surrounded by countries which import a lot of energy (i.e. Germany and the UK), so they can offload excess power there and avoid putting their plants into ERPO. If Germany and the UK had similarly high amounts of nuclear, the system would not work and a lot of plants would experience reliability issues.

    All this is to say, nuclear is an excellent energy source for making up a large, unvarying chunk of energy production (say, ~30%) but anything much more than that can cause more problems than it solves. One power source which can provide reliable on-demand time-varying energy is… batteries! Which is one of the reasons that recent advances in battery + solar are so exciting to me. A power grid made up of solely nuclear and renewables working together to meet time-varying demand is now completely plausible. So we dont have to choose between nuclear or renewables per se, we just have to deploy each in a way that suits its own merits.

    • alsimoneau@lemmy.ca
      link
      fedilink
      arrow-up
      1
      ·
      42 minutes ago

      What about nuclear + storage (pumped hydro, batteries) then? That should let you up the baseload a bit right.

    • Souvenir@lemmy.dbzer0.com
      link
      fedilink
      arrow-up
      15
      arrow-down
      1
      ·
      1 day ago

      Might I just add that nuclear isn’t exactly dealing with climate change and water shortages that well.

      It’s something I never really thought about, but plenty of nuclear plants have faced climate related issues in recent years, and been forced to shutdown or reduce output.

      Also, in an age of drone warfare, decentralised power production is potentially also a huge plus.

      • davetortoise@reddthat.com
        link
        fedilink
        arrow-up
        7
        ·
        1 day ago

        This is true. We hear about it happening a lot in mainland europe because there are a lot of inland reactors relying on rivers/reservoirs, however coastal reactors aren’t vulnerable in the same way. Climate change certainly isn’t making nuclear obsolete, but it definitely changes the way we need to think about cooling systems

        • Souvenir@lemmy.dbzer0.com
          link
          fedilink
          arrow-up
          3
          ·
          edit-2
          20 hours ago

          Of course, coastal reactors are vulnerable in other ways. Climate change can exacerbate extreme weather events. It’s the annoying thing about lots of stuff, you only really find out what goes wrong, when it goes wrong.

          Unknown unknowns, as some arsehole once put it.

          Also, coal contains small amounts of uranium and thorium which gets concentrated in the fly ash. Fly ash which then gets spread across the area surrounding the power plants. So I’m certainly not saying nuclear is obsolete or particularly dangerous compared to alternatives like coal.