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Thu May 6, 2021, 06:38 AM

'It's like the embers in a barbecue pit.' Nuclear reactions are smoldering again at Chernobyl

https://www.sciencemag.org/news/2021/05/nuclear-reactions-reawaken-chernobyl-reactor

Thirty-five years after the Chernobyl Nuclear Power Plant in Ukraine exploded in the world’s worst nuclear accident, fission reactions are smoldering again in uranium fuel masses buried deep inside a mangled reactor hall. “It’s like the embers in a barbecue pit,” says Neil Hyatt, a nuclear materials chemist at the University of Sheffield. Now, Ukrainian scientists are scrambling to determine whether the reactions will wink out on their own—or require extraordinary interventions to avert another accident.

Sensors are tracking a rising number of neutrons, a signal of fission, streaming from one inaccessible room, Anatolii Doroshenko of the Institute for Safety Problems of Nuclear Power Plants (ISPNPP) in Kyiv, Ukraine, reported last week during discussions about dismantling the reactor. “There are many uncertainties,” says ISPNPP’s Maxim Saveliev. “But we can’t rule out the possibility of [an] accident.” The neutron counts are rising slowly, Saveliev says, suggesting managers still have a few years to figure out how to stifle the threat. Any remedy he and his colleagues come up with will be of keen interest to Japan, which is coping with the aftermath of its own nuclear disaster 10 years ago at Fukushima, Hyatt notes. “It’s a similar magnitude of hazard.”

The specter of self-sustaining fission, or criticality, in the nuclear ruins has long haunted Chernobyl. When part of the Unit Four reactor’s core melted down on 26 April 1986, uranium fuel rods, their zirconium cladding, graphite control rods, and sand dumped on the core to try to extinguish the fire melted together into a lava. It flowed into the reactor hall’s basement rooms and hardened into formations called fuel-containing materials (FCMs), which are laden with about 170 tons of irradiated uranium—95% of the original fuel.

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Response to William Seger (Original post)

Thu May 6, 2021, 07:16 AM

1. It sounds like they've still got some time in hand . . . .

But the idea of the Elephant's Foot changing to sand, weird.

There's a Nova episode called "Suicide Mission at Chernobyl" from the 1980s about the engineers and scientists going into the basement to find out where the fuel went. It's absolutely fascinating.

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Response to hatrack (Reply #1)

Thu May 6, 2021, 07:31 AM

2. the HBO "Chernobyl" mini-series was awesome and dealt with some of that

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Response to LymphocyteLover (Reply #2)

Thu May 6, 2021, 09:16 AM

10. Greg Mazin who created the show "Chernobyl" sis an amazing job. It felt like you were

there. Interesting story about Mazin, he is known as kind of a “pilot” guru who can watch the pilot of a show and tell if it will be successful. Benioff and Weiss who were friendly with Mazin asked him to critique the pilot to Game of Thrones. He told Benioff and Weiss that it entire episode was unwatchable and needed to be redone.It was pretty good advice as GOT is one of my top shows of all time. Chernobyl, the mini series, is well worth watching. After watching it I did some follow up on the “internets” and was surprised to see that while a few of the first responders died, some literally melted from radiation exposure, quite a few of the characters involved lived and some are still living. However, the human toll it took on the surrounding area was horrible with spiking cancer rates, birth defects, and suicides as a huge mass of populated land had to be permanently relocated. Now people go there as a tourist attraction( stupid yes) and it’s like time stopped. Everything was left in its place when they bused the population out. It’s like a time capsule peering into life during the Soviet Union in the 80’s.

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Response to hatrack (Reply #1)

Thu May 6, 2021, 07:39 AM

3. Some more info on the Elephant's Foot

Chernobyl and Fukushima are two reasons we should move toward solar rather than increased reliance on nuclear power.

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Response to Best_man23 (Reply #3)

Thu May 6, 2021, 08:40 AM

4. Disagree. Nuclear is a necessary evil if we want to "go green" and cut carbon emissions

It will have to be a mixture of renewable resources and nuclear in order to have the capacity for today's society. The upshot to nuclear is that it creates jobs regulating and ensuring accidents like these never happen again.

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Response to dsp3000 (Reply #4)

Thu May 6, 2021, 09:04 AM

7. It's not an "evil" at all. It's our last best hope.

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Response to Best_man23 (Reply #3)

Thu May 6, 2021, 08:43 AM

5. Modern nuclear technology is leaps ahead of old designs

Without nuclear, there will be little real progress. Until far better storage technology is invented solar & wind will never be the main answer. If we are serious about climate change, nuclear MUST be part of the discussion. Without it, we're just pissing in the ocean

The Chernobyl reactor was a horrible Russian design.
Fukishima should have never been built where it was.

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Response to Best_man23 (Reply #3)

Thu May 6, 2021, 09:30 AM

11. Issues with both of those plants were well known

The Soviet/Russian reactors do not have the multiple layers of fail safes that the American and European counterparts do. Our reactors are much more safe than the one like Chernobyl were.

The Japanese plant was considered dangerous by some engineers as it was being developed (know someone who was involved with this type of plant when they were being built). Not wise to put a nuclear reactor in tectonically active zones or where tsunamis or hurricanes are likely to cause major damage. (Of course, oil refineries should not be built in those zones either, but that is a different argument for a different day).

For the US, that means stay out of the southeast around the Gulf and Atlantic oceans. Avoid building in California because of the San Andreas. (Maybe make an argument for avoiding potentially active areas of the New Madrid fault system, but I would need to defer to someone who has taken a lot more physical geology classes than I did as an undergrad many moons ago). A large portion of the central US lies on the NOrth American craton and would be a good place to build. Large parts of the midwest and rocky mountain states are tectonically stable and good candidates.

It still leaves the issue of what to do with spent fuel -- but all in all replacing the remaining natural gas (still at least the plurality provider of electricity in the US), coal, and oil plants with a mix of nuclear, wind, and solar is a good idea. The advantage to nuclear is that the output does not rely at all on the weather or affected by the seasons so that even on cloudy windless days energy still flows at a controllable rate.

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Response to William Seger (Original post)

Thu May 6, 2021, 08:59 AM

6. It may work a little like Oklo did 1.8 billion years ago...

...running at low power in a cyclic fashion. Oklo however took place in a huge uranium ore formation. The failed Chernobyl reactor contains far less uranium, and as any fission zones are almost certainly operating on a thermal spectrum, there is no opportunity for breeding. The moderator here is probably residual graphite, the original moderator, possibly enhanced by water.

Chernobyl exploded after a full fuel cycle. Nuclear reactors do not shut down when the fuel is exhausted but rather when the accumulation of neutron absorbing fission products reaches a significant level. This means that there is already significant samarium in the melt, which will offer some measure of control. The highly absorbing radioactive Europe isotopes, 152, 154, and 155 have all likely mostly decayed to gadolinium. Of these decay products of Gd, only 155 is a true neutron poison, and not quite as good as 157, although a neutron flux will certainly end up generating Gd-157 controlling the extent to which the fission zones remain active.

I'm quite sure that people who know next to nothing about nuclear engineering will carry on endlessly about this finding, to the extent it is confirmed, but as a threat to humanity it is nowhere near as great a threat as are leaking abandoned natural gas wells. Criticality accidents have taken place many times in the history of the development of nuclear technology without the world ending.

I, by contrast, find it interesting but I'm certainly not lose sleep over it except to the extent that it inspires the fear and ignorance and wishful thinking about so called "renewable energy" that is driving climate change.

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Response to NNadir (Reply #6)

Thu May 6, 2021, 05:36 PM

14. what is Oklo?

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Response to LymphocyteLover (Reply #14)

Fri May 7, 2021, 12:40 AM

15. The half-life of uranium-235 is much shorter than that of U-238. As a result...

1.8 billion years ago, all of the uranium on Earth was enriched uranium. Because of rising oxygen levels in the atmosphere, uranium was oxidized to U(VI) which is mobile. Over several eons, uranium ores formed in such a way as to allow water to percolate through the ores. The result is that the ores went critical, and natural nuclear reactors operated for several hundred thousand years.

The Oklo formations have been studied extensively to give insight to the behavior of fission products, so called "nuclear waste," in the environment. Over nearly two billion years, in a porous formation, they didn't travel very far, in the worst case a few hundred meters.

There is a Wikipedia page about the subject: Natural Nuclear Reactors There are well over 4,000 scientific papers that can be found in Google Scholar using the search term Oklo natural reactor.

I just looked in my files; I've downloaded something like 50 or 60 of them over the years. It's quite an interesting tale, and it addresses in many ways how silly some "arguments" about nuclear energy can get, particularly when dangerous fossil fuel waste, aka "air pollution," is responsible not only for climate change, but about 19,000 deaths a day - more than Covid on its worst day - assisted by biomass combustion waste.

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Response to NNadir (Reply #15)

Fri May 7, 2021, 07:20 AM

17. Thanks for the info!

very interesting

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Response to William Seger (Original post)

Thu May 6, 2021, 09:14 AM

8. Embers that'll grow cold in how many million years? ...

Zebus, what's lurking in the cellar?!?!

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Response to marble falls (Reply #8)

Thu May 6, 2021, 09:16 AM

9. Oh please...

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Response to William Seger (Original post)

Thu May 6, 2021, 03:28 PM

12. Is nuclear power necessary? No.

BUT, to get from 80% to 100% renewable is hard and expensive without it.

Good article:
Ryan Jones, an expert in electricity systems and a co-founder of Evolved Energy Research, a consulting company that models low-carbon transitions, agreed. “Anyone who says that nuclear is 100% necessary on a technical basis, I would claim, just hasn’t looked at the alternatives in enough detail,” he said in an email.

Most experts FactCheck.org contacted, including those who think nuclear power should remain an option, said that from a technical perspective, nuclear is not needed to decarbonize the grid.

But technically possible is not the same as practically feasible, or the most cost-effective. In that regard, many, although not all, researchers say nuclear — or something like it — is likely to be necessary to some degree. And even if nuclear is ultimately not needed, they say, the safer strategy is not to exclude it.

“All the evidence says it is possible to decarbonize the energy system in the U.S. without using nuclear power,” said Jones. But, he added, there are cases, such as places that don’t have good wind resources, in which building new nuclear plants can reduce the cost of decarbonizing. Depending on the region, he said, “getting to 100% renewable energy is either very expensive or necessitates significant new transmission to import resources from elsewhere.”

https://www.factcheck.org/2019/11/what-does-science-say-about-the-need-for-nuclear/

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Response to scipan (Reply #12)

Thu May 6, 2021, 03:34 PM

13. Something else interesting from the article:

In 2016, while working for the National Oceanic and Atmospheric Administration, Clack published one of the first “supergrid” papers in Nature Climate Change, which showed that by building out high-voltage, direct-current transmission lines, the U.S. could lower its electricity-sector carbon dioxide emissions by as much as 80% below 1990’s level, without an increase in the cost of electricity.

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Response to scipan (Reply #13)

Fri May 7, 2021, 09:07 AM

18. Of course, rather than read pop articles, one could read tons of...

...technical information about how copper is made, for just one tiny bit of information.

I've been studying all of the wishful thinking about how "energy conservation" would save the world my entire adult life, and I'm certainly not young.

Last week we hit 420 ppm at the Mauna loa atmospheric carbon dioxide observatory and frankly wishful thinking leading to this result passes me off.

Of course, since I make the study of energy and its external costs both in the environmental and health sphere, a priority, and because I give far more than a rat's ass about these issues, I know what Jevon's Paradox is all about.

It has a Wikipedia page. Anyone could look it up, were they actually interested.

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Response to scipan (Reply #12)

Fri May 7, 2021, 01:10 AM

16. Bullshit.

We've spent trillions of dollars on so called "renewable energy" in this century.

Humanity is now consuming over 600 exajoules of energy per year. The unsustainable solar and wind industry hasn't succeeded at providing 15 exajoules, despite all the cheering and idiotic hatred of nuclear energy.

Here's the result: Weekly average CO2 at Mauna Loa

I download the results of the Mauna Loa Observatory's carbon dioxide data every damned week and have done so for decades. At the end of the 20th century, the rate of accumulation of new carbon dioxide in the atmosphere was 1.59 ppm/year, expressed as a 12 month running average of increases over 10 years. As of this week 2.44 ppm/year.

The blind faith is so called "renewable energy" is a direct cause of this. Unfortunately, most people embracing this faith based approach to the tragedy of climate change, google their way lazily to anti-nuke pop websites, generally written by journalists whose scientific knowledge and engineering knowledge is as weak as the people who believe this anti-nuke crap.

There is in general, little evidence that most of these people have ever opened a science book

After many decades of study in the primary scientific literature on subjects of energy and the environment, I have come to conclusion that anti-nukes are the moral and intellectual equivalents of anti-vaxxers, anti-GMO types, etc.

There is a reason that humanity abandoned so called "renewable energy" in the 19th and early 20th century: That is because most people, even more so than today, lived short, miserable lives of dire poverty.

Faith in so called "renewable energy" is therefore not progressive; it's reactionary.

Nuclear energy need not be perfect, nor does it need to be without risk, to be vastly superior to everything else. It only needs to be vastly superior to everything else, which it is.

19,000 people have died today from air pollution. Another 19,000 will die tomorrow, and the day after that, and the day after that.

Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015 (Lancet 2016; 388: 1659–724) One can easily locate in this open sourced document compiled by an international consortium of medical and scientific professionals how many people die from causes related to air pollution, particulates, ozone, etc.

The direct reason for this is anti-nuke fear and ignorance, again, being morally and effectively equivalent to the similar anti-vax mentality, which as of today is actually killing more people than Covid is.

Nuclear energy saves lives:

Prevented Mortality and Greenhouse Gas Emissions from Historical and Projected Nuclear Power (Pushker A. Kharecha* and James E. Hansen Environ. Sci. Technol., 2013, 47 (9), pp 4889–4895)

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Response to William Seger (Original post)

Sun May 9, 2021, 09:40 AM

19. They're playing fast and loose with "nuclear reactions"

Growing numbers of neutrons could be caused by more than one factor - including just normal nuclear decay (which is also a "nuclear reaction" ).

But an actual criticality necessarily produces radioiodine... and there are loads of detectors around Chernobyl that couldn't miss that.

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