One issue with micro-reactors is that they make non-proliferation harder. It's much easier to verify that no uranium goes missing from 100 giant reactors than 100,000 small ones.

You could always install the 100,000 small reactors at 100 large sites.

Are there any micro-reactor designs that use non-enriched or minimally enriched uranium? My understanding is that natural uranium isn't really that dangerous, even in a dirty bomb, and then in terms of proliferation it already isn't that hard to get it.

Yeah. Uranium for sale, no permits: https://unitednuclear.com/index.php?main_page=product_info&c...

Most reactors use somewhere in the range of 3-5% U235 (compared to .7% naturally). That by itself won't let you make a bomb, but it gets you about 1/8th of the way to 20% which is about where a bomb is possible.

I assume the risk is that a bad actor could make a dirty bomb from the uranium. If that's the case, how does the risk of that compare to the risk of other attacks against our water supplies, pipelines, bridges, or even poison gas attacks?

How do you compare the deaths from a distributed reactor network to the deaths from additional global warming?

As others pointed out - just because you have lots of micro reactors, they all don’t have to be in individual locations.

And there are far more easily obtainable things than uranium if you want to construct a dirty bomb. Another fantastic anti-nuke red herring.

The 100,000 smaller reactors can still be put in the same place as the 100 giant reactors to make inspection and monitoring easier. The modular design makes incremental capacity upgrades easier, makes maintenance and repair easy, and helps to put more testing and QA on the modular design. Just think of it as 100 locations where you can either have 1 giant reactor each or up to 1000 modular micro-reactors.

I love the idea, but how much energy to micro-reactors provide today, on a commercial basis?

NuScale is the furthest along. Their design has been certified by the NRC, their first project is scheduled to come online towards the end of this decade.

As much as you need. Modern designs are modular - chain together as many as you need to provide base load and also provide some overage so you have coverage when they do inevitably need servicing.

Or since they are modular if significant long term loads shift geographically, you can easily move them around to where needed too.

I agree the concepts of massive plants aren’t desireable - luckily there are alternatives if we can ever get past the emotional arguments and actually discuss things rationally.

They sound awesome, but as far as I know they still haven't been commercialised so their potential is still largely unknown.

NuScale is still moving, but they have slipped on schedule and budget, far enough some of their project partners have pulled out.

So far everyone who's pursued this small modular reactors built by factories approach has failed in the ambition. Doesn't mean it's impossible but just maybe we should be a bit more bearish than bullish on the idea of this sparking a revolution in the capital costs and time scales of nuclear power.