Two interesting things to see here, of many. They are really planning the sites to be temporary compared to the solar/wind/ and other industrial power plants that have little or no plan for returning their sites to the original virgin soil. And two, they seem to use a molten salt loop like in concentrated solar to meet variable demand without changing the power level of the reactor, which you can't really do because of Xenon poisoning. So it's like a natural gas plant in its ability to deliver power, but clean and holds 20 years of fuel inside the reactor.
So why has nuclear waste become a thing that's not mentioned anymore? It was a pretty big thing in the 90's, now it seems to get brushed under the rug for all this 'safe' nuclear power marketing. It's mot just meltdowns and containment breaches that are a problem with nuclear power. None of the renewable alternatives produce radioactive waste that needs to be stored and dealt with.<p><a href="https://en.m.wikipedia.org/wiki/Radioactive_waste" rel="nofollow">https://en.m.wikipedia.org/wiki/Radioactive_waste</a><p>>Exposure to radioactive waste may cause health impacts due to ionizing radiation exposure. In humans, a dose of 1 sievert carries a 5.5% risk of developing cancer,[12] and regulatory agencies assume the risk is linearly proportional to dose even for low doses. Ionizing radiation can cause deletions in chromosomes.[13]
The walk away passive safety is a tradeoff with non-proliferation concerns. This design requires 20% enrichment, much higher than traditional reactors. This might be a smart tradeoff, but let's not pretend it's doesn't exist.<p><a href="https://www.aps.org/units/fps/newsletters/201810/reactors.cfm" rel="nofollow">https://www.aps.org/units/fps/newsletters/201810/reactors.cf...</a>
For a more dense read, see the whitepaper[1] from Oak Ridge National Laboratory about FCM fuels, which seems to be one of the key innovations of this reactor type. Instead of using pellets of Uranium oxide directly inside the reactor, this method encapsulates the fuel in a high temperature ceramic material which makes it very unlikely for the reactor to 'melt down' the way that mainstream reactors can.<p>[1] <a href="https://info.ornl.gov/sites/publications/Files/Pub42476.pdf" rel="nofollow">https://info.ornl.gov/sites/publications/Files/Pub42476.pdf</a>
Seems like their claim to "Ultra Safe" is actually merited based on a first principles look at the power density. They claim 1.24 W/cm^3 versus 20-40 W/cm^3 in normal reactors. The high power densities mean you have to be able to cool the reactor, even when you shut down the reactor because reactors take a long time to actually turn off. With such low power density, it should be no problem to cool down the reactor. It'll just cool down naturally, like a hot pot. In fact the metric to look at would be power per core surface area.
Assuming nuclear truly can be ultra safe, how do you convince a public that has seen Chernobyl, Three Mile Island, and Fukushima to get on board? Particularly when the "competition" (solar, wind, etc) has such a strong tailwind.
Random renewable energy-related question that I've been thinking about:<p>Specifically wrt solar, a big argument against is that it can't provide power during the night and we don't have a good way to store energy. What I'm wondering is why it's so imperative that residential/commercial properties are able to get full power from the grid 24/7? What if prices for power go way up during the night (because it can't come from solar), and people could just learn to get most of their power from the grid during the day? And have a relatively small per-house battery that charges during the day and can be used at night.
Eh. In my view, nuclear is very clearly safe enough, and has been for some time.<p>What's more interesting to me is whether it's <i>cheap</i> enough.
Safety is no longer the reason Nuclear is not worth it.<p>The sun is a giant, free nuclear fusion plant in the sky. We can capture 1/5th of its output per square meter. For free!<p>The wind -- caused by solar heating -- also generates free power.<p>The cost of harvesting it is now so low, and will always continue to decline as any technology will, that any fuel-based generation mechanism is going to be rendered uneconomic with time alone. They depreciate faster as time goes on!<p>Investing in any such generator needs to be for other reasons like land scarcity.
I once wondered if it would be possible to have a nuclear power station which operated subcritically with extra neutrons injected from an outside source. The advantage I saw was that turning off the outside source would instantly stop the reaction, no worrying about articulating fuel rods and poison injectors. Unfortunately decay heat is still an issue.<p>Turns out it's potentially a thing but has some technical challenges.
Nice animation but but...
I think nuclear is bad because the technology to make it is in the hands of a few big corps. That's the major downside, and of course, toxic waste.
At 5 MW, these MMR (Micro Modular Reactor) look like a specialized alternative to diesel generators servicing remote locations unserviced by the regular power grid. 20 year lifetime without refuelling is an attractive proposition if the capital costs are competitive.
Dr. Chris Morrison from USNC's space division presented to the Seattle Friends of Fission at Ada's<p><a href="https://youtu.be/39LGrJkDmho" rel="nofollow">https://youtu.be/39LGrJkDmho</a>
Illinois EnergyProf recently did a video on USNC's design: <a href="https://www.youtube.com/watch?v=7gtog_gOaGQ" rel="nofollow">https://www.youtube.com/watch?v=7gtog_gOaGQ</a><p>(Though I think he used audio from the wrong microphone; the earlier videos sound much better.)
Summary of discussion in this thread (from The West Wing)<p><a href="https://youtu.be/7fkMR96I0sw" rel="nofollow">https://youtu.be/7fkMR96I0sw</a>
In the page it isn't explained how it shuts down passively in a loss of coolant event? Since the coolant is not doing moderation, removing it doesn't reduce reactivity at all.<p>You have a 30 bar helium pressure vessel and heat exchangers etc. I wonder how much it's going to leak.<p>Not saying it's bad, just interested in these questions. Some other designs have these issues in focus.
Serious question: what happens when you take one of these fuel pellets and blow it up and disperse it in the atmosphere / water supply, either accidentally or on purpose?<p>Have they actually designed a solution or is this a fundamental safety risk with all nuclear fuels? All I see addressed is proliferation / reprocessing which is a different thing.
Wasn't something very similar in size proposed for use in Alaska?<p><a href="https://en.wikipedia.org/wiki/Toshiba_4S" rel="nofollow">https://en.wikipedia.org/wiki/Toshiba_4S</a>
I find it a little odd that a site called Hacker News is so bullish on nuclear power. Could there be anything less <i>hacker</i> than a centralized, exclusively government owned and operated source of power?<p>No thanks. I’d rather put more resources into solar, wind, and other sources of power that don’t depend on the government to not explode and irradiate the immediate area for hundreds of years.
So North Korea getting nuclear weapons is a big deal and using every text book measure to prevent Iran from building these things is quite an effort. But providing the whole world with material which can be used to build these damn things is not a problem?<p>Also there is big security problems all around the world due to terrorist. So how do we manage security with this small scale things?
I want to see how safe is this underground graveyard in case of a volcanic eruption... I'm sorry but I don't believe in nuclear, I think at the pace renewable and batteries are evolving now, they will be better alternative before a new nuclear plant is planned and constructed which takes many years.