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More invested in nuclear fusion in last 12 months than past decade

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Re: More invested in nuclear fusion in last 12 months than past decade

#341

Post by acidburnNSA »

adgjlsfhk1 wrote: post #338
acidburnNSA wrote: post #197

Earlier quoted context omitted.

Uranium and thorium fuel on earth can make 100% of today's primary energy for about 4 billion years, using breeder reactors, which were proven in 1952 near Arco Idaho at the Experimental Breeder Reactor 1. Writeup explaining this with lots of actual scientific references at the bottom here: https://whatisnuclear.com/blog/2020-10-28-nuclear-energy-is-... People who say uranium will last 50 years either aren't aware of…

This is making a lot of assumptions about what uranium is economically viable to extract. Specifically, this link appears to be assuming that it is possible to filter the entire oceans and Earth's entire crust for all the uranium and thorium they store. Those are both obviously unreasonable assumptions.

For seawater extraction, you just put enough uranium capture fibers in a few places and the uranium is delivered to you slowly over billions of years via ocean currents. This is well supported by the various articles and entire scientific issue featured in the See Also section.

But if you don't buy seawater extraction, check out the Weinberg 1959 reference (https://doi.org/10.1063/1.3060564), which contains a calculation for how much earth would need to be moved to power the entire world on granite. They calculate that we'd need granite mining from the crust about the same order of magnitude of the fossil fuel mining operations at that time. Of course, mining granite is far less destructive than mining fossil fuel, so it's totally acceptable.

Recall that there is 20x more nuclear energy in average crustal rock than there is chemical energy in coal, per kg. So to a breeder reactor, it's literally as if the entire earth's crust is made of pure coal, 20x over.

Will that last long enough for ya? :)

And with that kind of energy density, it's all economical to extract.

Re: More invested in nuclear fusion in last 12 months than past decade

#342

Post by lawrenceyan »

dongobongo wrote: post #330
lawrenceyan wrote: post #315

Earlier quoted context omitted.

Please correct me if I’m wrong, but isn’t it impossible for fusion to generate a nuclear meltdown scenario that fission has the potential for?

Meltdown accident: basically, reactor is turned off, however heat continues to be generated because of a thing called decay heat which is when isotopes generated by the fission reactions decay to more stable isotopes and release energy. It's about 7% of a fission reactor's power and continues for a few hours until it's negligible. 7% of a gigawatt reactor is like having a couple of jet engines going full blast inside…

If there's truly no meltdown risk with micro reactors, I'm all for it.

In terms of fusion, I'd much rather make the tradeoff of increased cost in order to remove issues of vulnerability completely. I want to be able to not even have to think about / plan for dealing with a meltdown scenario.

Re: More invested in nuclear fusion in last 12 months than past decade

#343

Post by acidburnNSA »

adgjlsfhk1 wrote: post #339
acidburnNSA wrote: post #331

Earlier quoted context omitted.

If you add district heating to LWRs their effective efficiency goes from 33% to over 57%. If we adjust markets to value on-demand (including nights/weekends/winters) low-carbon heat and electricity, LWR economics would be good, even in the USA. They're already expected to be essential for decarbonizing at scale. https://www.sciencedirect.com/science/article/pii/S254243511... I have plenty of rants about how LCOE is w…

That is probably a good idea, but comes with the major political problem of putting nuclear reactors very close to large populations of people who can complain about the zoning.

100 km isn't that close.

https://www.oecd-nea.org/ndd/workshops/nucogen/presentations...

Re: More invested in nuclear fusion in last 12 months than past decade

#345

Post by acidburnNSA »

miles wrote: post #340
acidburnNSA wrote: post #323

Earlier quoted context omitted.

That's basically a judge saying it. The scientific basis is very unclear.

> That's basically a judge saying it. The scientific basis is very unclear. "In January 2015, the MHLW [Ministry of Health, Labour, and Welfare] compiled medical knowledge on lung cancer and radiation exposure in a report resulting from a review meeting of medical experts, and published the immediate view similar to that for thyroid cancer. The first claim for case of lung cancer was approved by MHLW in August 2018,…

I understand that he received an estimated 74 mSv of radiation, somewhat below the level of 100 mSv acute / 300 mSv annual that has been shown to cause a measurable increase risk of cancer (e.g. from 40% lifetime risk to 40.1% lifetime risk). It's extremely dubious to say that this was definitely from Fukushima radiation. If that dose is accurate, the likelihood of it being from Fukushima radiation is probably less than 1%. Not impossible. But not likely, and far from a sure thing.

For comparison, the 23 firefighters who died from acute radiation syndrome at Chernobyl got doses as high as 13,400 mSv, almost 2000x higher than this guy.

Re: More invested in nuclear fusion in last 12 months than past decade

#346

Post by adgjlsfhk1 »

acidburnNSA wrote: post #343
adgjlsfhk1 wrote: post #339

Earlier quoted context omitted.

That is probably a good idea, but comes with the major political problem of putting nuclear reactors very close to large populations of people who can complain about the zoning.

100 km isn't that close. https://www.oecd-nea.org/ndd/workshops/nucogen/presentations...

Wow, point retracted. I'm honestly kind of shocked that heat can be transferred that efficiently.

Re: More invested in nuclear fusion in last 12 months than past decade

#347

Post by miles »

acidburnNSA wrote: post #345
miles wrote: post #340

Earlier quoted context omitted.

> That's basically a judge saying it. The scientific basis is very unclear. "In January 2015, the MHLW [Ministry of Health, Labour, and Welfare] compiled medical knowledge on lung cancer and radiation exposure in a report resulting from a review meeting of medical experts, and published the immediate view similar to that for thyroid cancer. The first claim for case of lung cancer was approved by MHLW in August 2018,…

I understand that he received an estimated 74 mSv of radiation, somewhat below the level of 100 mSv acute / 300 mSv annual that has been shown to cause a measurable increase risk of cancer (e.g. from 40% lifetime risk to 40.1% lifetime risk). It's extremely dubious to say that this was definitely from Fukushima radiation. If that dose is accurate, the likelihood of it being from Fukushima radiation is probably less t…

> I understand that he received an estimated 74 mSv of radiation

"The ministry said he had been exposed to about 195 millisieverts (mSv) of radiation. The International Commission on Radiological Protection recommends avoiding more than 1-20 mSv per year, and according to Reuters, exposure to 100 mSv a year is 'the lowest level at which any increase in cancer risk is clearly evident.'" https://time.com/5388178/japan-first-fukushima-radiation-dea...

Re: More invested in nuclear fusion in last 12 months than past decade

#348

Post by acidburnNSA »

miles wrote: post #347
acidburnNSA wrote: post #345

Earlier quoted context omitted.

I understand that he received an estimated 74 mSv of radiation, somewhat below the level of 100 mSv acute / 300 mSv annual that has been shown to cause a measurable increase risk of cancer (e.g. from 40% lifetime risk to 40.1% lifetime risk). It's extremely dubious to say that this was definitely from Fukushima radiation. If that dose is accurate, the likelihood of it being from Fukushima radiation is probably less t…

> I understand that he received an estimated 74 mSv of radiation "The ministry said he had been exposed to about 195 millisieverts (mSv) of radiation. The International Commission on Radiological Protection recommends avoiding more than 1-20 mSv per year, and according to Reuters, exposure to 100 mSv a year is 'the lowest level at which any increase in cancer risk is clearly evident.'" https://time.com/5388178/japan-…

That's 100 mSv acute. Did he get it acutely (i.e. in a day or two) or over years? If acute then yes, the measurable increment over a background 40% lifetime risk could be due to Fukushima. So then the question is what's the increment? Let's estimate that it's 1% (based on the noisy data at these still quite low doses). In that case, there is a 1 in 40 chance that his cancer death in 2016 was due to Fukushima in 2011.

It it wasn't acute and accumulated over >1 year, then there's a ~0% chance it was from Fukushima radiation.

Re: More invested in nuclear fusion in last 12 months than past decade

#349

Post by sacrosancty »

grej wrote: post #53
sacrosancty wrote: post #38

Earlier quoted context omitted.

Fusion isn't a silver bullet even if it works. If it costs more than solar+battery then it's worthless.

Totally disagree. Solar + battery will never match the energy density of fusion.

Why do we need high energy density? Are you imagining a future society with much higher energy use?

Re: More invested in nuclear fusion in last 12 months than past decade

#350

Post by sacrosancty »

tremon wrote: post #101
sacrosancty wrote: post #38

Earlier quoted context omitted.

Fusion isn't a silver bullet even if it works. If it costs more than solar+battery then it's worthless.

No, this is way too shortsighted. Fusion allows us to use other energy sources than our own sun, which means it's essential for viable space missions, and we won't need to compete with the rest of nature (including agriculture!) for our energy needs. Hydroponics with fusion technology allows us to produce food without relying on the sun at all. I'd say that alone is worth the investment.

I totally agree in the long term for space travel. But for our current energy use, it could be useless if it costs even a little bit too much. Kind of like solar concentrators are worthless because PV got too cheap.
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