[QUOTE=xilman;516364]It turns out that nuclear fission is renewable in this sense. Seawater contains accessible amounts of uranium and thorium which can be extracted fairly easily. [URL="https://newatlas.com/nuclear-uranium-seawater-fibers/55033/"]The technology[/URL] is very new and came to public attention (well, my attention) only a few weeks ago.[/QUOTE][QUOTE=Dr Sardonicus;516378]Fine by me. Perhaps the new technology could be applied to the brine coming out of a desalination plant.[/quote]
That is what my thoughts were. I was in a meeting earlier this week talking about RO in the 100's of millions of litres or gallons per day range. I wonder how practical it might be to wash the ash of sewage sludge and run it through this process.
[quote]Of course, with fission power, the perennial bugbear is, "What do we do with the waste?"[/quote]The answer to much of that is to not be frightened children about it. Reprocess it, make breeder reactors, and use cyclotronicly supported/induced fission to deal with some of the waste (which will give off enough energy to supply power to the grid.)

As for a lot of the other waste issues, try to get politics out of it. NIMBY is bad when your back yard is the best place to plant this stuff. Also, some of the storage strategies are little more than extensions of the short term storage. True long term might look different.

Re: fission reactor waste
[QUOTE=Uncwilly;516385]<snip>
The answer to much of that is to not be frightened children about it. Reprocess it, make breeder reactors, and use cyclotronicly supported/induced fission to deal with some of the waste (which will give off enough energy to supply power to the grid.)

As for a lot of the other waste issues, try to get politics out of it. NIMBY is bad when your back yard is the best place to plant this stuff. Also, some of the storage strategies are little more than extensions of the short term storage. True long term might look different.[/QUOTE]Of course, since reprocessing is governed by law, you [i]can't[/i] "get the politics out of it." Practically speaking, then, it would seem to be necessary to get the politicians on board with reprocessing, etc. This means, either getting a large part of the public on board, or a single-issue group with a large enough dedicated following to swing elections.

The current impasse WRT storing waste at Yucca Mountain may be useful in this regard.

As I understand it, reprocessing is fraught with concerns other than NIMBY, e.g. nuclear proliferation and terrorism. WRT proliferation, I suppose one could answer that concern with "That ship has sailed."

[QUOTE=Dr Sardonicus;516392]As I understand it, reprocessing is fraught with concerns other than NIMBY, e.g. nuclear proliferation and terrorism. WRT proliferation, I suppose one could answer that concern with "That ship has sailed."[/QUOTE]Waste: use it as an energy source (as in RTGs); mine it for commercially useful radiation source (PET, radiography , etc); burn it in reactors (a special case of using it as an energy source.

Proliferation: a strong argument for using thorium reactors, over and above the fact that Th is an order of magnitude more abundant than U.

[QUOTE=Dr Sardonicus;516392]As I understand it, reprocessing is fraught with concerns other than NIMBY, e.g. nuclear proliferation and terrorism.[/QUOTE]Waste that is sufficiently radioactive is essentially terrorism-proof. Anything that kills the would-be terrorist long before it can be used on anyone else is actually rather safe in that respect.

A strong argument for storing waste in large and not easily manageable quantities.

[QUOTE=Dr Sardonicus;516378]Once we're in the "hundreds of megayears" range, the human habitability of the Earth starts coming into question anyway...[/QUOTE]Yup. There may not be much of a biosphere left on the earth in a half a gigayear because the sun will have evolved to produce significantly more output. As I said, in the long term everything is dead.

Good discussion - back in my younger days I also believed that "nuclear done right" was the way to go, but no one has yet done nuclear right, as far as I can tell. So some ripostes:

- First off, an article re. [url=https://www.answers.com/Q/What_is_the_carbon_footprint_of_nuclear_energy]the carbon footprint of nuclear power[/url], note the numerous ways in which said footprint is typically grossly understated by ignoring./minimizing various unsustainable aspects of the process, from mining to waste disposal to plant decomissioning;

- Breeder reactors carry inherent nuclear proliferation potential, and even model citizen France is cheating by [url=https://www.bbc.com/news/science-environment-26425674]using sequestration-based waste storage[/url];

- Waste repositories simply *cannot* be made safe on civilizational timescales - we simply have too few data re. safety of long-term storage, and once a large-scale such repository is compromised in some unexpected or underestimated-odds fashion and sh*t starts leaking out, you are well and truly screwed, multiple-Fukushimas-style. Paul may be correct about a really "hot" storage facility being an automatic deterrent to terrorism, but you need to get the stuff there first, and all those local small-scale temporray-storage sites around the plants generating the waste are much softer targets for terrorism. You just need *one* tiny container of hot waste or the contents of one RTG to make their way into a dirty bomb and all of a sudden the calculus is completely changed. The only safe nuclear waste is that which is not generated to begin with.

- Invoking magical future and "just around the corner" technologies like "safe, clean nuclear fusion" (it's not clean, in point of fact, as done on earth) or "cheap nuclear fuel from seawater!" or "Thorium to the rescue!" is bogus, especially given the rapidly accelerating timescales at which global warming appears to be happening;

- With all nuclear tech, you have to get both private industry and government on board, and have that process not undermined by massive corruption TEPCO, anyone?

- With solar, you have to factor in the extremely toxic technologies and currently unsustainable practices (e.g. mining/processing of rare earths) involved in capture technology and power management and storage. No solar-power storage tech has ever been scaled anywhere near what would be needed to support truly large-scale solar PV energy production. Contrast wild-eyed optimistic pieces like [url=https://www.greentechmedia.com/articles/read/iea-report-renewables-third-global-generation]this[/url] with cold, [url=https://en.wikipedia.org/wiki/Solar_power]hard reality[/url] - "In 2017, solar power provided 1.7% of total worldwide electricity production, growing at 35% per annum". At the current level, storage tech is only a minor factor - if one wants to get into the tens of %, though, at those levels it becomes a huge issue. And current battery tech (e.g. for e-vehicles) is being done in completely unsustainable fashion, in terms of envirnmental impacts of battery production and the need for safe disposal including materials reprocessing.

Now compare the effort and environmental impact of that 2%-level global solar deployment to "what if the governments of the world's highest-consuming nations simply made a concerted effort to get their citizens to consume 2% less 'stuff'?" That is the angle Ilargi is promoting - compare the carbon footprint of a first-world consumer to a rural African villager. The former consumes on the order of 100x more than the latter. What % reduction is it reasonably possible for the former to make without sacrificing the truly necessary (to one accustomed to first-world living) modern-world niceties? And let's not forget the wildly disproportionate consumption of our dear global elites, e.g. twits like George Clooney private-jetting-and-yachting and multiple-large-estate-maintaining around the world, [url=https://www.fastcompany.com/90346515/george-clooney-releases-psa-against-climate-change-dumbfkery]telling the proles how to live sustainably[/url].

[QUOTE=ewmayer;516424]<snip>
[url=https://www.answers.com/Q/What_is_the_carbon_footprint_of_nuclear_energy]the carbon footprint of nuclear power[/url], note the numerous ways in which said footprint is typically grossly understated by ignoring./minimizing various unsustainable aspects of the process, from mining to waste disposal to plant decomissioning;[/quote]
It's good to note that nuclear power is not without a carbon footprint, but I'm guessing the part of the "carbon footprint" of a coal or gas-fired power plant from [i]burning the fuel[/i] will swamp those from fuel extraction and transport, plant construction, etc. I don't know how the "carbon footprint" of mining and transporting coal compares to that of mining and processing uranium ore, and delivering fuel to the plant. I would imagine extracting and transporting natural gas has a smaller carbon footprint -- unless you spew a whole LOT of it into the atmosphere, as happened in California not that long ago.
[quote]Now compare the effort and environmental impact of that 2%-level global solar deployment to "what if the governments of the world's highest-consuming nations simply made a concerted effort to get their citizens to consume 2% less 'stuff'?" That is the angle Ilargi is promoting - compare the carbon footprint of a first-world consumer to a rural African villager.
<snip>[/QUOTE]
Never mind rural African villagers -- how about people living in the US during, say, the 1960's? I know that I never heard of "self storage" facilities when I was a kid. Now, a lot of people here in the good ol' USA have so [i]much[/i] stuff, they can't keep all of it where they live.

[QUOTE=xilman;516405]Proliferation: a strong argument for using thorium reactors, over and above the fact that Th is an order of magnitude more abundant than U.[/QUOTE]

The thorium fuel cycle is not totally unusable for making bombs, although U-233 is a lot more difficult to work on than the usual U-235 and Pu-239. Some U-232 is also created in the thorium breeding process, and it has some very strong gamma emitters in its decay chain. But if U-233 was the only thing available, we (as in the humankind) would use it, no doubt about that. Even India has made one small yield U-233 bomb test back in 1998. Fortunately (?) especially Pu-239 is so much easier to work with.

[url=https://earther.gizmodo.com/the-dirty-truth-about-green-batteries-1833922990]The Dirty Truth About Green Batteries[/url] | Gizmodo. A reader comments:
[quote]This is a horribly optimistic spin of the actual facts. I recommend the full report, which I also think is somewhat over-optimistic. It waves away CdTe and CIGS as niche solar technology, but polycrystalline PV has a much higher lifecycle GHG use (way worse than the most common nuclear plants), and assumes into existence recycling programs that don’t exist yet and doesn’t mention how energy intensive recycling is.

Also they frequently say in X years demand exceeds current production, which is rather irrelevant because metals that have other uses that aren’t tied to renewables will have higher current production and they assume they can just take over that whole market.

Either way section 5 ‘Environmental and social impacts of supply’ should be widely circulated to the ‘renewables will save us’ crowd.[/quote]
Re CdTe -- ugh, cadmium and tellurium, both toxic. All these technologies should be viewed through a "how toxic is the entire mining-to-device manufacturing chain, and are the end product either low-toxicity or reasonably 99% recoverable?" lens. If the products and processes involved are not 'green' by any sane definition, neither is the energy generated by same.

Until November 3, 1982, I was as ignorant as gravel about the way rivers with deltas behave over time. In fact, I had never even heard the [i]word[/i] "deltaic" used to describe such rivers. But that night I watched an episode of the PBS program [b]NOVA[/b] entitled [i]Goodbye Louisiana[/i], narrated by Burt Lancaster. The program explained that deltaic rivers naturally change course every so often, as sediment deposit builds up the delta around its present course, and a steeper path to the sea becomes available off to the side somewhere.

In the present instance, [url=https://en.wikipedia.org/wiki/Old_River_Control_Structure]Wikipedia[/url] informs us:
[quote]Between 1850 and 1950, the percentage of latitude flow entering the Atchafalaya River had increased from less than 10 percent to about 30 percent. By 1953, the U.S. Army Corps of Engineers concluded that the Mississippi River could change its course to the Atchafalaya River by 1990 if it were not controlled, since this alternative path to the Gulf of Mexico through the Atchafalaya River is much shorter and steeper.

The Corps completed construction on the Old River Control Structure in 1963 to prevent the main channel flow of the Mississippi River from altering its current course to the Gulf of Mexico through the natural geologic process of avulsion. Historically, this natural process has occurred about every 1,000 years, and is overdue.[/quote]

Later, I read a piece, [i]Atachafalaya[/i] by John McPhee; it was originally published in the [i]New Yorker[/i] (February 23, 1987 issue) and later as part of a book, [u]The Control of Nature[/u]. He wrote:[quote]For the Mississippi to make such a change was completely natural, but in the interval since the last shift Europeans had settled beside the river, a nation had developed, and the nation could not afford nature. The consequences of the Atchafalaya’s conquest of the Mississippi would include but not be limited to the demise of Baton Rouge and the virtual destruction of New Orleans. With its fresh water gone, its harbor a silt bar, its economy disconnected from inland commerce, New Orleans would turn into New Gomorrah.

Moreover, there were so many big industries between the two cities that at night they made the river glow like a worm. As a result of settlement patterns, this reach of the Mississippi had long been known as "the German coast," and now, with B. F. Goodrich, E. I. du Pont, Union Carbide, Reynolds Metals, Shell, Mobil, Texaco, Exxon, Monsanto, Uniroyal, Georgia-Pacific, Hydrocarbon Industries, Vulcan Materials, Nalco Chemical, Freeport Chemical, Dow Chemical, Allied Chemical, Stauffer Chemical, Hooker Chemicals, Rubicon Chemicals, American Petrofina—with an infrastructural concentration equalled in few other places—it was often called "the American Ruhr." The industries were there because of the river. They had come for its navigational convenience and its fresh water. They would not, and could not, linger beside a tidal creek

For nature to take its course was simply unthinkable. The Sixth World War would do less damage to southern Louisiana. Nature, in this place, had become an enemy of the state.[/quote]

The lower Mississippi came to my attention recently, with news that, for the first time since it was completed in 1931, the Bonnet Carré Spillway was opened for the second time the same year, following heavy rains in the lower Mississippi after an unusually wet winter.

The following articles by Weather Underground may be of interest. Climate change may be playing a role, which gives me an excuse to put this item in this thread (plus, I wasn't sure where else to post it), though the more immediate danger seems to be the silting up of the channel, which raises the height of floods for a given volume of water.

[url=https://www.wunderground.com/cat6/Americas-Achilles-Heel-Mississippi-Rivers-Old-River-Control-Structure]America's Achilles' Heel: the Mississippi River's Old River Control Structure[/url]

[url=https://www.wunderground.com/cat6/Escalating-Floods-Putting-Mississippi-Rivers-Old-River-Control-Structure-Risk]Escalating Floods Putting Mississippi River’s Old River Control Structure at Risk[/url]

[url=https://www.wunderground.com/cat6/If-Old-River-Control-Structure-Fails-Catastrophe-Global-Impact]If the Old River Control Structure Fails: A Catastrophe With Global Impact[/url]

From the Department of "Let's replace facts with ideology" ...
 

[url=https://www.washingtonpost.com/climate-environment/2019/06/08/white-house-blocked-intelligence-aides-written-testimony-saying-human-caused-climate-change-could-be-possibly-catastrophic/?noredirect=on]White House blocked intelligence agency’s written testimony saying human-caused climate change could be ‘possibly catastrophic’[/url]
[quote]According to several senior administration officials, all of whom spoke on the condition of anonymity to talk about internal deliberations, Trump officials sought to cut several pages of the document on the grounds that its description of climate science did not mesh with the administration’s official stance. Critics of the testimony included [url=https://www.washingtonpost.com/national/health-science/white-house-readies-panel-to-assess-if-climate-change-poses-a-national-security-threat/2019/02/19/ccc8b29e-3396-11e9-af5b-b51b7ff322e9_story.html?utm_term=.5bf44ef915b9&noredirect=on]William Happer[/url](*), a National Security Council senior director who has touted the benefits of carbon dioxide and sought to establish a federal task force to challenge the scientific consensus that human activity is driving recent climate change.[/quote]

(*) For the benefit of those whose browsers won't go there,[quote]The White House is working to assemble a panel to assess whether climate change poses a national security threat, according to documents obtained by The Washington Post, a conclusion that federal intelligence agencies have affirmed several times since President Trump took office.

The proposed Presidential Committee on Climate Security, which would be established by executive order, is being spearheaded by William Happer, a National Security Council senior director. Happer, an emeritus professor of physics at Princeton University, has said that carbon emissions linked to climate change should be viewed as an asset rather than a pollutant.[/quote]Reminds me of the Advisory Commission on [strike]disenfranchising minority voters[/strike] Election Integrity.