Thread

NRC issues first U.S. construction permit for a BWRX-300 small modular reactor

151 points · 191 comments · papa-whisky

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. sandworm101 · 1790757425 · focus · HN ↗
  From thier website: "The BWRX-300 power block is small enough to fit within two international football pitches."
  And after some digging, the core alone is 4.2m INNER diameter and over 27m tall. That is smaller than average but this is a far cry from the sales pitch of reactor modules being mass produced in a factory to be delivered to site by truck.
  <a href="https://www.gevernova.com/content/dam/gevernova-nuclear/global/en_us/documents/carbon-free-power/005N9751-BWRX-300-General-Description.pdf" rel="nofollow">https://www.gevernova.com/content/dam/gevernova-nuclear/glob...
  1. mpweiher · 1790759289 · focus · HN ↗
    The label SMR applies to a wide range of reactors.
    The BWRX-300 is at the upper end of that range and I don't think claims of factory-production of the whole unit were ever made for this reactor.
    That said, even the much larger AP-1000 had fairly large modules made in a factory. In fact as far as I understand that was one of the problems with the Vogtle builds, because doing that only really makes sense for a larger number of units, not for just two unites.
    preisschild · 1790772060 · focus · HN ↗
    Yes, exactly. But even the sub 5 MWe microreactors that are often shown in those truck demos require lots of shielding that has to be done on-site beforehand.
    mpweiher · 1790860700 · focus · HN ↗
    So you figured out this glaring hole in their plans that all the idiot companies doing SMRs missed?
    Maybe not.
    For example, Aalo Atomics has split the construction process in such a way that the on-site pour that happens after the reactor is delivered from the factory is (a) very simple (b) standardized, and (c) non-nuclear. In addition, the site work that is required is very repetitive, so you get a positive learning curve, again without the slowness of nuclear construction.
    Copenhagen Atomics has heavy thorium salt shielding inside the nuclear core and a "Cocoon" that is delivered in 12 prefab parts installed on a regular concrete pad. So on-site construction is making the non-nuclear concrete pad, installing the pre-fab cocoon on pad and then placing the reactor core inside the Cocoon.
    Westinghouse apparently ships the entire eVinci microreactor pre-assembled with shielding.
    X-energy puts the reactor in a hole underground.
    etc.
  2. T-A · 1790766770 · focus · HN ↗
    Going by the last table at
    <a href="https://www.icetransport.com/blog/what-are-the-maximum-oversize-load-dimensions-on-us-highways" rel="nofollow">https://www.icetransport.com/blog/what-are-the-maximum-overs...
    ("Oversize/Overweight Permit Limits by State (Standard Freight Loads") that should be deliverable by truck with a permit.
    mrngld · 1790771505 · focus · HN ↗
    That discusses 'superloads', I hadn't heard it called that before but it's accurate in the sense that things like self-propelled modular transporters (or towed equivalents) can move just about anything just about anywhere IF the road infrastructure all along the route is amenable to it.
    Pictures don't do them justice, they're amazing to see in person. I think a typical SMR is on the small end of what's possible to move by road.
    crote · 1790841942 · focus · HN ↗
    So are wind turbines. "Deliverable by truck" in this sense means "physically fits on a closed-down highway", not "you'll randomly pass it on your commute".
  3. alightsoul · 1790784378 · focus · HN ↗
    The reactor vessel is technically always factory made, and the containment building (pit?) structures are built as separate prefabricated modules that are just lowered into the containment building, like a prefabricated building is assembled on site

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