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Ultra Safe Nuclear

usnc.com

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Re: Ultra Safe Nuclear

#171

Post by Symmetry »

VBprogrammer wrote: post #4

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. Turns out it's potentially a thing but has some technical challe…

The problem is less about preventing criticality and more about handling the decay heat from all the isotopes produced when it was critical. That's going to give you 10% of the heat you had been producing with the reactor on for a little while after you stop the chain reaction.

Re: Ultra Safe Nuclear

#172

Post by jvanderbot »

Tade0 wrote: post #140
semi-extrinsic wrote: post #87

Earlier quoted context omitted.

There was a comment here about cleanup costs of nuclear vs. solar, that was deleted while I was typing my response to that. I'm just gonna copy in my response here, because I think it's an interesting topic: Are we really sure solar panels are much easier to dismantle on a euro-per-kWh basis though? That is, if you divide the total cost of dismantling and recycling a solar power plant, divided by the total amount of…

EDIT: my numbers regarding annual kWh/m2 were wrong. Are you sure you would spend significantly less than 150 euros per square meter of panel to dismantle, transport and recycle the solar panels? Yes, because it's being done by leading companies and doesn't seem to diminish their competitive advantage: http://www.solarscorecard.com/2018-19/scorecard-2018-19.php

And, by pairing your comment with parent, a nuclear power company would have a competitive advantage over solar, but for the head start that solar go due to gov incentives, massive investment, and lack of a scare movie like Chernobyl.

Re: Ultra Safe Nuclear

#173

Post by Fooloo »

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?

Also there is big security problems all around the world due to terrorist. So how do we manage security with this small scale things?

Re: Ultra Safe Nuclear

#174

Post by arkitaip »

manfredo wrote: post #17
grawprog wrote: post #8

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. https://en.m.wikipedia.org/wiki/Rad…

Because it's not a problem. There's actually very little of it. It occupies a volume the footprint of a football field and 10 yards high [1]. Storing it is pretty foolproof: bury it in an area with no aquifer. The main risk of contamination is getting into the groundwater. If there's no groundwater the risk of contamination is eliminated even if the containers decay over time. And lastly, it doesn't make sense to bur…

> This number may sound like a lot, but it’s actually quite small. In fact, the U.S. has produced roughly 83,000 metrics tons of used fuel since the 1950s—and all of it could fit on a single football field at a depth of less than 10 yards.

A football field of forever death is not a comforting mental image.

Re: Ultra Safe Nuclear

#175

Post by cj »

sambull wrote: post #16
teilo wrote: post #2

I'm all for the concept, but so far, everything I've seen has been nothing but concept.

Large awesome graphic page on the fuel, and how its super safe. Nothing about how they 'conceptualize' disposing of their waste.

The video on their homepage explains their approach to waste disposal. About 60 seconds into the video.

Re: Ultra Safe Nuclear

#176

Post by aperrien »

arkitaip wrote: post #174
manfredo wrote: post #17

Earlier quoted context omitted.

Because it's not a problem. There's actually very little of it. It occupies a volume the footprint of a football field and 10 yards high [1]. Storing it is pretty foolproof: bury it in an area with no aquifer. The main risk of contamination is getting into the groundwater. If there's no groundwater the risk of contamination is eliminated even if the containers decay over time. And lastly, it doesn't make sense to bur…

> This number may sound like a lot, but it’s actually quite small. In fact, the U.S. has produced roughly 83,000 metrics tons of used fuel since the 1950s—and all of it could fit on a single football field at a depth of less than 10 yards. A football field of forever death is not a comforting mental image.

How large are those toxic fields of coal ash again?

Re: Ultra Safe Nuclear

#177

Post by TeMPOraL »

arawde wrote: post #163
philipkglass wrote: post #148

Earlier quoted context omitted.

Most toxic elements last forever. That includes the toxic elements in coal ash. Both coal ash and spent nuclear fuel need indefinite safe storage. It can be cheaper to store spent nuclear fuel because it's so much more compact than fossil fuel waste. Remember that the status quo already has a large forever-waste cost of its own. Nuclear waste is a trade off vs. other kinds of waste, and it is cheaper than the status…

Wanted to leap in here to mention tailings from minings projects. The gold that goes into a circuitboard comes from a mine which likely has a tailiings facility and associated dam, which is essentially an open pit filled with water into which tailings are dumped. They're incredibly toxic materials. We had an engineer go out to the field and take a sample of some tailings, and after 6 months of being left in a lab, th…

Not to mention, industrial chemical processes in general.

Toxic waste requiring indefinite safe storage is the default state. Spent nuclear fuel is actually nice here in a way, because in some cases, it's a self-solving problem (dangerous stuff decaying into less dangerous stuff over time).

Re: Ultra Safe Nuclear

#178

Post by wazoox »

z8rHZM8Svhu8hE2 wrote: post #161
steeve wrote: post #28

Earlier quoted context omitted.

A few hints: - read about CIGEO - nuclear waste, once it has decayed, becomes metal in glass - nuclear waste is _small_, see [1], the nuclear fuel waste is the tiny red cube. - wind turbines have a 20 years lifespan, after which the blades are buried and forgotten, and will stay there forever [2] - renewables are more CO2 intensive than nuclear, fuel cycle included, see IPCC reports (there is a debate for nuclear vs…

- wind turbines have a 20 years lifespan, after which the blades are buried and forgotten, and will stay there forever Nuclear power plants have a lifespan of about 50 years, after which the reactor and other parts will be radioactive. This waste must be buried, will be forgotten and will remain there forever.

Actually nuclear plant have been designed for a minimal lifespan of 40 years. Most can be run safely 60, 80 or even maybe 100 years.

Renewables don't provide the energy density to power our industrial world. Simple as that.

Fossils emit much more pollution than nuclear in volume, and that will last arguably as long (CO2 we're dumping in the atmosphere will stay up there for millennia; coal ashes will remain toxic forever and we make megatons of them, not mere kilos).

Re: Ultra Safe Nuclear

#179

Post by simonebrunozzi »

hairytrog wrote: post #156

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…

> which you can't really do because of Xenon poisoning

Can you clarify this part? You mean that channging the power level of the reactor would cause Xenon poisoning?

Re: Ultra Safe Nuclear

#180

Post by quonn »

V6HBGNQHU wrote: post #98
mdorazio wrote: post #66

Earlier quoted context omitted.

How many people with increased cancer rates from solar? Stop quoting deaths from nuclear accidents - the harm from nuclear incidents goes far beyond killing people outright.

How many people die from loosing power during winters and freezing to death? How many more would that be if everyone was using solar which can't provide enough power in winter?

I doubt anyone freezes to death in the EU, US, Australia, and Canada because of loosing power in winter.
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