Comment by throw0101c

5 hours ago

> Nuclear power plants need to be taken offline for multiple weeks to months at a time for refueling

CANDU reactors, for one, can be (and are) refuelled live:

* https://en.wikipedia.org/wiki/Online_refuelling

Every few decades they do need to be refurbished though.

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throw0101c

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Retric  4 hours ago

Cutting out the “and maintenance” bit is misleading.

It’s commonplace for maintenance issues at non CANDU reactors to extend the “refelling” downtime. So no, CANDU can’t stay online for decades without maintenance and instead have similar downtime issues. The major benefit is when manufacturing plutonium due to shorter fuel cycles, but overall CANDU reactors are less cost effective which is why adoption fizzled out.

  • throw0101c  4 hours ago

    > So no, CANDU can’t stay online for decades without maintenance and instead have similar downtime issues.

    There are several situations:

    * refuelling occurs

    * maintenance and/or inspection needs to happen

    * refurbishment may be desired

    Some of these things take downtime, some do not, depending on the design of the reactor and other factors. A blanket statement of "refuelling forces a downtime" is incorrect in many situations. Depending on the maintenance (or inspections) needed, this may or may not need downtime. Refurbishment generally means tearing things apart, so usually means downtime, but if a site has multiple reactors they can be done one at a time, e.g.:

    * https://news.ontario.ca/en/release/1006993/ontario-delivers-...

  • throwaway2037  4 hours ago

    Eh, again, I disagree. As an example: Many CANDU reactors have insanely high availability. Example: Qinshan CANDU Unit 1 only had a planned outage of less than 27 days in 2023. There are many other examples. That is crazy uptime in the world of electricity production. And to be clear, if you come at me with "Oh, what about the major maintenance required every 10+ years?". Thermal (coal/gas) has the same issue.