Coping with Nuclear Reactor Leakage: Lessons from Chernobyl and Fukushima

[gilakmesum]

how do we cope with leakage of nuclear reactors as happened at Chernobyl and Fukushima plan

 

[FactChecker]

I am not an expert, but here is my three cents (corrections or clarifications are welcome):
The initial air contamination could not be contained. Contaminated soil from fallout can be removed in a very small area around the reactors, but Chernobyl will have a large area that will be uninhabitable for hundreds of years. How long depends on the half-life of the material that escaped. A very large region of Eastern Europe suffered significant, but less, contamination. I think that most of it has returned to normal. Apparently, Fukushima air fallout was not as bad.

In both cases, they are still discovering what to do about the reactor ground contamination. Chernobyl was just buried and they recently moved a giant dome over it because the original cover was deteriorating. I guess they will just have to let things leak out below and suffer the consequences. They may not be very publicly open about the true situation.
Fukushima is so radioactive that it recently damaged a robot that was sent into investigate. So the cleanup will be a process of many decades. They keep putting water in it to keep it cool, and try to capture the water that drains away.

 

[gilakmesum]

I am not an expert, but here is my three cents (corrections or clarifications are welcome):
The initial air contamination could not be contained. Contaminated soil from fallout can be removed in a very small area around the reactors, but Chernobyl will have a large area that will be uninhabitable for hundreds of years. How long depends on the half-life of the material that escaped. A very large region of Eastern Europe suffered significant, but less, contamination. I think that most of it has returned to normal. Apparently, Fukushima air fallout was not as bad.

In both cases, they are still discovering what to do about the reactor ground contamination. Chernobyl was just buried and they recently moved a giant dome over it because the original cover was deteriorating. I guess they will just have to let things leak out below and suffer the consequences. They may not be very publicly open about the true situation.
Fukushima is so radioactive that it recently damaged a robot that was sent into investigate. So the cleanup will be a process of many decades. They keep putting water in it to keep it cool, and try to capture the water that drains away.

so if all can be contaminated,, why they still built a giant dome to cover it. And also how to process the water which was used to keep the nuclear reactor cool so that it will become neutral.

 

[phyzguy]

how do we cope with leakage of nuclear reactors as happened at Chernobyl and Fukushima plan

Why are people so much more concerned with the release of radiation from nuclear plants than they are with the release of radiation and chemical pollutants from coal burning plants or other chemical releases? This release of decades of coal ash released 1.1 billion gallons of ash, which had high levels of arsenic, lead, mercury, and many other pollutants. The environmental impact of this release of this material dwarfs what was released from Fukushima. It's hard to identify if anyone died due to the radiation release from Fukushima. By contrast, the Bhopal chemical release, killed thousands of people. Quoting Wikipedia,

"Estimates vary on the death toll. The official immediate death toll was 2,259. The government of Madhya Pradesh confirmed a total of 3,787 deaths related to the gas release. A government affidavit in 2006 stated that the leak caused 558,125 injuries, including 38,478 temporary partial injuries and approximately 3,900 severely and permanently disabling injuries. Others estimate that 8,000 died within two weeks, and another 8,000 or more have since died from gas-related diseases."

 

[mfb]

Coal has a death toll 1000 times larger than nuclear power - per kWh, in absolute numbers it is even worse.
At 10 trillion kWh per year, and with the death rate from above, we get one million coal-induced deaths per year, or 3000 per day.
As comparison: The death toll due to Chernobyl is estimated to be a few thousands (different sources get different numbers), all other nuclear reactors accidents are negligible compared to Chernobyl. Coal has the death toll of all nuclear accidents combined every two days.

Back to topic: Prevent further leakage, and then wait. The activity goes down over time, making handling the remainders easier. Nuclear accidents mainly release isotopes with half-lifes of a few days, and with half-life of 30 years. The former goes away quickly, the latter leads to long-term contamination. The Chernobyl accident happened 30 years ago, so we still have 1/2 of the material around. For important places like access roads it can be interesting to remove the top layer and store it somewhere safely.
Radiation levels around Chernobyl are not particularly high today. You can visit it. There are (inhabited) places that naturally have higher radiation levels than large parts of the exclusion zones. And there are people (and various animals and plants) living in those exclusion zones.

 

[FactChecker]

Fukushima update: Apparently they have found a hole in the floor of one reactor where the nuclear material melted through. Estimates are that "it will take hundreds and thousands of years to completely eliminate the radiation in the area." (see http://www.dinosmarkfactual.com/2017/02/japan-declares-state-emergency-reactor-leaks-ocean-v8.html)

 

[mfb]

Estimates are that "it will take hundreds and thousands of years to completely eliminate the radiation in the area."

What does that mean? Every place on Earth has been slightly radioactive as long as Earth existed. You cannot "completely eliminate the radiation in the area", not even without a nuclear reactor. You can just make sure the level is not significantly higher than natural.

 

[FactChecker]

What does that mean? Every place on Earth has been slightly radioactive as long as Earth existed. You cannot "completely eliminate the radiation in the area", not even without a nuclear reactor. You can just make sure the level is not significantly higher than natural.

It's a quote. I can't change it.
My guess is that he means it will take hundreds or thousands of years before we are unable to determine that the radioactive levels of the area are statistically significantly greater than the natural source radioactivity of that area.

 

[Astronuc]

It's a quote. I can't change it.
My guess is that he means it will take hundreds or thousands of years before we are unable to determine that the radioactive levels of the area are statistically significantly greater than the natural source radioactivity of that area.

We can measure background levels of radiation anywhere in the world. There are natural levels that vary according to location and altitude. As one ascends through the atmosphere, one experiences more cosmic radiation, which is quite natural.

People living in certain areas where uranium and thorium are found are exposed to higher levels of natural background radiation than those who live away from such areas.

Some reasonable good information on background radiation.
https://en.wikipedia.org/wiki/Background_radiation

When I was in graduate school, I spent some time in various laboratories, which had radiation monitors operating continuously. We could hear the occasional click from background radiation. It was probably on the order of one or two counts every 10 seconds. We have various sensitive detectors that can measure low levels of and low energy radiation. At some point, one will receive more radiation from solar UV than from other natural radiation sources. Sunburn is a form of radiation exposure, and acute exposure to the sun can make one sick, and greatly increase one's chance of cancer.

As for manmade radiation sources, we strive to minimize unnecessary exposure. However, in certain cases, including Chernobyl and Fukushima, negligence undermines safety protocols.

The new structure over the Chernobyl 4 unit is mostly to keep the weather out, and to mitigate uncontrolled release of whatever radionuclides are present. Most of the mitigation activities take place within the older structure and closer to the source.

 

[Aufbauwerk 2045]

In order to cope with the leakage, we of course try to stop it. This effort may cost lives, as it did at Chernobyl.

Assuming you mean how do we cope with the radioactivity that has already been released, basically you want to get away from the dangerous hot zones as quickly as possible. The entire town of Pripyat was evacuated, and is still off-limits for permanent residence. People can visit for short time periods, but they must be monitored for exposure.

A lethal dose may kill a person very quickly. In case you have been subjected to a lethal dose, but not enough to kill you quickly, then you will experience painful lingering death. This may take days or weeks.

In cases where there is somewhat less exposure, but still enough to cause significant damage, you may develop cancer. There are some emergency steps which may help. For example, in some cases it helps to take KI (potassium iodide) because this blocks radioactive iodine from being absorbed by the thyroid gland. Here is some information on this topic from the CDC.

https://emergency.cdc.gov/radiation/ki.asp

For a good overview of the problem, here is the main link from the CDC on radiation emergencies.

https://emergency.cdc.gov/radiation/index.asp

The World Health Organization also provides information.

http://www.who.int/mediacentre/factsheets/fs371/en/

Three more case studies are the short and long-term radiation effects of the atomic bombings of Hiroshima and Nagasaki, and the exposure of people in Utah due to atmospheric tests done in Nevada.

There is lots of information available about the short and long term effects of the atomic bombings. Sorry, I don't have any specific links at this time.

Apparently the Utah exposure is less well known. Here is more information on this topic.

http://historytogo.utah.gov/utah_chapters/utah_today/radiationdeathanddeception.html

It's advisable to study the CDC and WHO articles and understand the different types of radiation, their biological effects, and how they are measured.

In case someone is curious about the level of radioactivity in a certain area, It's not hard to monitor the environment using a radiation detector. These are available for a few hundred dollars.

I suppose the anxiety level on this topic and one's personal response may depend on where one lives. I don't live near a nuclear reactor, but I am near a high-value military target. So I think my chances of instant vaporization are better than my chances of a lingering death. There's really nothing I can do at this time about the instant vaporization threat, but I plan to move eventually to somewhere that is relatively safe, and build a shelter.

 

[mfb]

It's not hard to monitor the environment using a radiation detector.

For gamma and beta, sure. For alpha: not really. Most detectors will absorb them before they reach the sensitive parts, and even if they are designed to detect it, you have to be directly at the source (easy for air, not easy for everything else), and you have to estimate how much of those particles a human will absorb.

A high short-term dose is much more dangerous than a lower long-term dose rate. 0.5 Sv received in a day can lead to notable radiation poisoning. There are places lake Ramsar where you naturally get more than 1 Sv as life-time dose, which doesn't lead to radiation poisoning. It is not even clear if it leads to higher cancer doses.

 

[Aufbauwerk 2045]

For gamma and beta, sure. For alpha: not really.

Thanks for the information. I provided links for those who want to learn more from authoritative sources.

Concerning alpha particles, here is a very brief summary.

https://orise.orau.gov/reacts/guide/alpha.htm

Speaking of a lingering death, specifically by alpha particles, this reminds me of radiation poisoning by ingesting Polonium-210 . See the Litvinenko case for details.

 

[Rive]

how do we cope with leakage of nuclear reactors as happened at Chernobyl and Fukushima plan

That depends on the priorities. Most cases the 'leakage' is some minor stuff, which can (and: will) be cleaned up fast, without any real impact.

Large scale 'leakage' is rare. Based on the three major cases (Mayak, Chernobyl, Fukushima: only two are NPP related) to 'cope' starts with the localization of the leakage. After that it burns down to priorities. In case of Mayak, even the localization is a partial faliure, the result is an area where not many thing can live. This is the worst possible result I think.
In case of Chernobyl, the localization is ~ successful, but there were no further steps: the result is a wide area, where the not-so-severe radiation works as a human-repellent, but has minuscule effect on life. The result is an environment where wildlife can flourish freely without human impact. Regarding the environment, maybe this is the best result available.
In case of Fukushima, the affected area will be slowly decontaminated, so the human-repellent effect will slowly vanish. The wildlife which already started to regenerate will be cut down back, but still there will be areas where human life will be restricted. Neither wildlife, nor human society really wins - the second worst or second best result. Pick one.

Fukushima update: Apparently they have found a hole in the floor of one reactor where the nuclear material melted through. Estimates are that "it will take hundreds and thousands of years to completely eliminate the radiation in the area." (see http://www.dinosmarkfactual.com/2017/02/japan-declares-state-emergency-reactor-leaks-ocean-v8.html)

That source is so thoroughly crap, that... OMG. Is there even just one sentence there which is right?

 

[Aufbauwerk 2045]

Here is some more information on Chernobyl. In general, please be sure to look at actual data and historical records, and learn something about the science, as opposed to listening to mere opinions or propaganda.

http://chernobylgallery.com/chernobyl-disaster/radiation-levels/

Regarding coping with the Chernobyl situation, there is a good documentary called The Battle of Chernobyl. It includes many interviews with people who were involved at the time, including Gorbachev.



This documentary is quite low-key, which was very wise. If they had called it "We Almost Lost Europe" they would have been accused of sensationalism.

People debate about how long the Chernobyl Exclusion Zone will be operational. Pripyat is still a ghost town, and there have been numerous mutations reported among the wildlife. But workers can apparently stay in the area for up to three weeks before rotating out.

 

[mfb]

and there have been numerous mutations reported among the wildlife

More than elsewhere? Reference?
Mutations happen all the time. It is called evolution.

I don't think I have ever seen an unbiased documentary using "uncensored" in its title.

 

[Aufbauwerk 2045]

Here is another video, from the Youtube channel of one of the film makers.



I just saw it for the first time. Very interesting information I have not seen elsewhere on video.

 

[nikkkom]

so if all can be contaminated,, why they still built a giant dome to cover it.

Europeans are scared about a possibility of current "Sarcofagus" collapsing. This was a perfect opportunity for European businesses and Ukrainian bureau-klepto-crats to make them shell out lots of money for any project which promised to prevent it. Of course, the bigger the project, the more it costs, the better. Thus, the option of reinforcing current "Sarcofagus" had no hope of being chosen instead.

 

[gilakmesum]

Europeans are scared about a possibility of current "Sarcofagus" collapsing. This was a perfect opportunity for European businesses and Ukrainian bureau-klepto-crats to make them shell out lots of money for any project which promised to prevent it. Of course, the bigger the project, the more it costs, the better. Thus, the option of reinforcing current "Sarcofagus" had no hope of being chosen instead.

could it be a some kind sabotage to Chernobyl so that the "huge" business can come into? Just guess...

 

[etudiant]

could it be a some kind sabotage to Chernobyl so that the "huge" business can come into? Just guess...

Think the initial accident was just that, a failed test run at 3 am, when demand and also operator effectiveness are at their nadir.
Since then, a free for all.
Oddly enough, the communists who installed the sarcophagus were less corrupt than their successors, who even sold the contaminated vehicles from the cleanup graveyard. The expensive new cover is a visible symbol for the governments of Europe to demonstrate to their people that the problem is contained for 100 years by their combined efforts. Plus a fat source of fees and kickbacks all up and down the line.
Still, it is a nice piece of engineering and took a lot of dedicated work to come into being.

 

[gilakmesum]

Think the initial accident was just that, a failed test run at 3 am, when demand and also operator effectiveness are at their nadir.
Since then, a free for all.
Oddly enough, the communists who installed the sarcophagus were less corrupt than their successors, who even sold the contaminated vehicles from the cleanup graveyard. The expensive new cover is a visible symbol for the governments of Europe to demonstrate to their people that the problem is contained for 100 years by their combined efforts. Plus a fat source of fees and kickbacks all up and down the line.
Still, it is a nice piece of engineering and took a lot of dedicated work to come into being.

The price they should pay was very high...

 

[Rive]

Europeans are scared about a possibility of current "Sarcofagus" collapsing. This was a perfect opportunity for European businesses and Ukrainian bureau-klepto-crats to make them shell out lots of money for any project which promised to prevent it. Of course, the bigger the project, the more it costs, the better. Thus, the option of reinforcing current "Sarcofagus" had no hope of being chosen instead.

It's not just that. To reinforce that building would have meant to dismantle at least some part of it -> the remnants of the core exposed to the free air, even if just temporally.
Also, since there is no second defense line, the workers would have no other option just to work in clean sight of the core remnants.
These times the ruins of the core are already accessible, but such visit still eats up ~ a year worth of dose allowance (by EU standards). Even with the distance bigger, it would mean a hell of a schedule to keep all the workers below the dose limits. Like in Fukushima, just with a lot worse environment.

 

[mheslep]

Think the initial accident was just tha

You believe Chernobyl was sabotage and not, say, incompetence laced with arrogance?

 

[nikkkom]

It's not just that. To reinforce that building would have meant to dismantle at least some part of it -> the remnants of the core exposed to the free air, even if just temporally.

The remains of the core are exposed to air even right now:

 

[mfb]

Exposed to air inside the sarcophagus. Hence the sarcophagus.

 

[nikkkom]

Sarcophagus is not airtight. It is even not watertight and not bird-tight...

 

[Rive]

Sarcophagus is not airtight. It is even not watertight and not bird-tight...

What matters most these days is that it is still sight-tight.
Mostly, at least.
One of the biggest rugs of the world.

 

[nikkkom]

What matters most these days is that it is still sight-tight.
Mostly, at least.

Exactly. Also google "2013 roof collapse". Spending $1.5B on the Ark, but can't find hundreds of times less money to keep turbine building roof from rusting through??

Instead of making existing structures impenetrable to rainwater, air drafts and birds, which is neither difficult nor particularly expensive, people in charge of the operation are building gargantuan and astoundingly costly structures. This continues for years, no, now decades, on end.

 

[mfb]

It stops the direct radiation and solid radioactive material and contains most of the dust. Most of the volatile elements should be gone by now.

Instead of making existing structures impenetrable to rainwater, air drafts and birds, which is neither difficult nor particularly expensive, people in charge of the operation are building gargantuan and astoundingly costly structures. This continues for years, no, now decades, on end.

Do you suggest you know it better than the experts working on it?

 

[nikkkom]

Do you suggest you know it better than the experts working on it?

I know very well how the "experts" at pilfering public finances of Ukraine operate.

For one, they force engineering experts to write reports in a way which justifies the most expensive projects, not the most useful ones.

 

[Rive]

Instead of making existing structures impenetrable to rainwater, air drafts and birds, which is neither difficult nor particularly expensive

But it is. Even the construction of the new steel thing started with digging up the whole construction area for any nasty stuff and replace the soil partially, otherwise there was no chance to met the requirements for working conditions.
I cannot see how could those requirements met up in the air around the (old and during the process: partially dismantled) sarcophagus.

 

[nikkkom]

I cannot see how could those requirements met up in the air around the (old and during the process: partially dismantled) sarcophagus.

There is no need to dismantle Sarcophagus, neither partially nor fully.
The opposite: it needs to be "mantled" more. Walls reinforced with steel beams. Currently exposed debris should be covered with concrete, until a state is reached where no radioactive dust is generated. Then isolate everything against water ingress (nowadays there are dozens of various polymeric and epoxy sealers which make concrete completely water-impenetrable).

This plan has one fatal flaw: it is way too _cheap_!

 

[mfb]

Can we keep discussion on technical aspects please? This is a science forum.

 

[Bigjoemonger]

so if all can be contaminated,, why they still built a giant dome to cover it.

When the containment building exploded the melted fuel became exposed to outside air. Which is very bad. A gust of wind or water could carry it and severely contaminate a wider area. So to stop this they just dumped tons and tons of concrete on top. Calling it a tomb. But concrete directly exposed to radiation breaks down over time. Meaning one day it'd be a huge issue again. The ultimate goal is to actually clean up the corium to get rid of the problem. The process of cutting out that concrete to get to the corium will kick up a ton of radioactive dust. The dome is a seal over it so none of that radioactivity is able to further harm the surrounding area.

 

[nikkkom]

But concrete directly exposed to radiation breaks down over time.

On what timescales does concrete lose its integrity?

 

[girts]

I think that the loss of integrity depends mostly on the place where the concrete is used for example whethet it is in a structural element under stresd or whether it is simply dumped in a large pile on top of radioactive crap in ordet to contain it , anyway

Since this is a science forums I was expecting a bit of clarity in simplicity about the matters discussed.

as to the Chernobyl contamination point and contamination in general, I tend to think that the danger from the buried Chernobyl unit 4 is very low or next to nothing by now and that there is a much higher risk of contamination escaping if the surrounding forests burn in a wildfire for example.
The phrase "leaking radioactivity" is a bit foolish to my opinion simply because as we know radioactivity can't walk or talk it can only expand from a radioactive source, so when someone says that the Chernobyl reactor is leaking radiation both in air or in the ground water I want to ask by what means?

Sure after the 1986 accident it indeed emitted a lot of aerosols or in everyday language "dust" which was then the major reason for the exclusion zone contamination but after the majority of the fission reactions halted and the tangled mess cooled down it became much less dangerous in terms of contamination because hit me if I'm wrong but there isn't any noticeable amount of dust that can escape from a wet and moist pile of metal and concrete mixed with bunch of heavy metal and all that sitting at atmospheric temperatures.
Nor I think there's much that can escape into the ground either from beneath the reactor, the only thing that probably escaped was the fire and rain water mixed with some amount of radioactive particles.

I must admit I know firsthand that there is a high level of corruption in Ukraine which is usually hard to understand to most westerners, but I can't agree that the ark is simply a tax scheme, because in the long run it would be easier to dismantle the innards of the reactor using automatic cranes and a secondary containment structure to keep the dust inside because whenever you dismantle things dust appears.

I think their not repairing the turbine hall roof because there isn't any airborne pollutants inside or atleast not to any significant amount and as far as I know they are already underway in a process to dismantle the turbine and machine hall as that is the easiest part in all of the power plant to dismantle in terms of cleaning from contamination.Although ultimately in the case of Chernobyl I'm not sure whether there is any gain in dismantling or atleast trying to dismantle the reactors now because the surrounding land will still be inhabitable for the next 100 years and there isn;t anything that we can do about it realistically speaking so my opinion is we can let the reactor sit there and decrease in radioactivity over time and then in the future deal with it.
taking it away would require using up another space to store the materials and there are tons and tons of them there. plus taking them away doesn't lower the background radiation levels in the exclusion zone anyway.
but that's just my opinion.

surely the bottom line is there is only one good way of dealing with contamination - not making it in the first place, as for nuclear reactors - avoiding accidents or leaks and keeping a tight inspection schedule and operator morale