The best part of this story is that all of the older people in Japan stepped up to work on cleanup so the younger people would not have to suffer . Cancer from radiation poisoning takes many years to kill you and they figured they were already old so why not save the young from this fate . Faith in humanity still stands tall !
"Cancer from radiation poisoning takes many years to kill you" Radiation poisoning assumes you managed to swallow something radioactive. Very high level radiation exposure usually either kills you or (temporarily) knocks out your immune system, making you susceptable to dying of the common cold. There's a body of evidence that it doesn't so much cause cancer (which are generally caused by chemical precursors) but the weakened immune system allows cancers which are already present to get a foothold. The 2 strong pointers about most radiation exposure not being cancerous are simple: Aircrew (who get more occupational high level exposure than any other group and aren't exactly dropping like flies) and smokers (who accumulate significant quantities of polonium in their lungs and yet take decades to develop lung cancers - which actually seem to be triggered by exposure to the polonium breakdown products (such as lead) rather than the actual radiation) That said, water-moderated reactors are inherently dangerous(*)(**) and should be banned - they're so dangerous that the guy who designed and built the first one was deeply disturbed by their use in civil power plants and used the nuclear aircraft project to develop a far safer alternative which is completely walk-away safe - molten salt reactors. These were tested and operated in the 1960s but R&D was shut down for political reasons in 1972 by that nice mr Nixon chap. (*) Nuclear power is 300,000 times safer than coal fired power and in fact is statistically safer than every other form of electricity generation - but (read below) it could be a few thousand times safer still and generate less than 1% of the tiny amount of waste(***) it does. (**) without radioactives in the mix, a steam explosion in a nuclear power plant is just that - a steam explosion. Mixing water and nuclear materials is a fundamentally bad idea as it means that things can escape to the biosphere - furthermore, _every_ civil nuclear accident so far (even Chernobyl) has involved+been exacerbated by water and wouldn't have been possible in a molten salt design. Molten metal moderators such as sodium seem like a good idea on paper, but no matter how much the engineers claim they know what they're doing and "it won't catch fire, honest", they've caught fire - and even a non-nuclear-loop sodium fire is bad news as you can see if you read the reports of what happened at Monju. (***) The entire high level nuclear waste output of a 800MW nuclear reactor over a 60 year lifespan will fit comfortably in an olympic size swimming pool and be safe to handle in about 350-400 years (NOT 20,000). As-is, it also happens to be quite usable sidestream fuel for those mollten salt reactor designs mentioned above.
Faith in humanity my ass. If that were the case shut down all nuclear reactors World wide. With so many other sources for energy there are far better and much safer to you not to mention cheaper to build 2 harness the energy
Chris Block Can we assume that you are happy for people in the oil and gas industry or mining to take physical risks on your behalf yet the negligible risk of radiological contamination is too much for you, being unwilling to share the risks involved in being resident in an advanced society? Yes Japan is a terrible place for a nuclear power station ha ha.
Great video. All the necessary details and easy to understand. I would like news reports to be like this, not the very superficial coverage that is usually available to the public.
Andres M. Yes, I agree. Now we need a dialogue page maintained by GE the designer of the initial Fukushima system. The dialogue page will allow for sensible discussion and free exchange of ideas for resolving this global disaster. GE is defensively shedding assets and stock value as we speak. This is to the shame of America.
GE has been run by bean counters and various business cocks rather than engineers for some time now - and that is why it is failing, not the Fukushima disaster. The fault lies with the plant owners, who had insufficient backups.
Don’t agree, it’s missing the key information. The impact on human and natural live, they don’t even detailed all the contaminated water pumped to the sea...
@@SVQGOT You're correct. With that said, in the context of what they were discussing, this video primarily focused on the Engineering failure. If it was simply a news video, I think more focus would have went to the effects that spread out from ground zero. In this case, the purpose was to explain the situation purely from within Fukushima, from the viewpoint of Engineers. That's why, I believe, they left out some of the information about the broader situation this disaster left.
8:08 The building is actually *designed* that way, so that if there's a hydrogen explosion in the superstructure, the walls of the structure actually give way and are blown apart, and thus the explosion doesn't get to damage the containment below. The design did its job as it was supposed to.
This video also show that had it not been for a design flaw with the generators (something TEPCO knew as far back as 1990) the power plant would have been able to keep operating even after an insane earthquake and tsunami.
It seems to me that in a country prone to earthquakes and the resulting tsunamis, it might've been prudent to elevate the diesel generators off the ground so that they couldn't flood.
They were - just not high enough. The problem was that they were built with Tsunamis in mind, but this one was over (I don't remember exact numbers) 4 m higher than highest anticipated.
This is the clearest explanation of reactor operations and the Fukushima accident that I've ever seen on UA-cam or the internet. I used to work at a BWR with exactly the same type of containment and ECCS, so I was interested in the slow, progressive failure of the various pieces of the ECCS, containment, etc. I especially appreciated the calm, detailed explanations. In my years of working at the BWR plant, I never, ever heard an accurate news report on events at the plant. The IRSN deserves praise for presenting the facts of the accident and its aftermath. A useful improvement on this video would be a report on radiation exposure for the various teams. Cycling 20,000 people through the wrecked plant sure sounds like many people reached their occupational exposure limit. Occupational exposure limits have changed since I first trained as a Navy Nuc and are much lower than they used to be.
This is what happens when you let TEPCO run nuclear power plants. They knew that the seawall at the Fukushima Daiichi nuclear power plant wasn't high enough, yet they still did stupid things like put the emergency generators in the basement of all places. The Onagawa nuclear power plant which was closer to the epicenter survived perfectly intact thanks to its 14 meter seawall.
This was a very good overview of the disaster. There were a few places where I wish the narrator went into a bit more detail, but overall it was a very interesting and informative watch.
They just started removing nuclear fuels 04-15-2019 and it is expected to take 2 years. The one from reactor 3 will be the hardest and they won’t start that until 2021 reports say
TL:DW: Whoever decided that building the backup generators on ground level, with no protective walls, on the coast, of a country prone to earthquakes and tsunamis, is directly and solely responsible for the entire meltdown and everything that resulted from it. End of story.
It is a rarity that someone(/s) of incredible intelligence can explain an intricate concept in a manner so easily understood - even by someone as blunt as I am! Thank you.
It seems that elevating and distancing their backup power sources would've at least reduced the risk of reactor damage, and at most would've prevented the disaster completely. Unlike other power plants, a nuclear plant must be able to maintain it's own power supply at any cost, and for a long duration.
In most situations, that was indeed the case. Unfortunately, they didn't seem to consider a tsunami that could breach the sea wall, and caused a common mode failure when it disabled all 13 diesel backup generators. True though - in hindsight, said generators should have probably been situated on higher ground.
@@WaterCrane First construction plans actually focused on that security issue.. It was cheaper installing the backup diesel generators closer to the plant, but at lower level making flooding a risk.. A Japanese engineer describes this failure on a documentary available on UA-cam.. He was ignored/silenced!
On 30 October 1991, Seawater leaked in the reactor's basement and one of two backup generators failed. An engineer informed his superiors of the possibility that a tsunami could damage the generators. en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disaster#1991:_Backup_generator_of_Reactor_1_flooded TOSHIO KIMURA (translated): I asked my boss back in the late '90s what would happen if a tsunami hit the Fukushima reactors. I said surely a meltdown will happen. He said 'Kimura, you are right'. But it was made clear that the issue of a big tsunami was taboo. A few years later I quit the company because of its culture of cover-ups. www.abc.net.au/pm/content/2011/s3240171.htm
Yes it is. The best way of a 'passive' cooling was the heat exchanger that relied on gravity and steam convection. But because the heat exchanger is a closed cycle, it can't maintain continuous operation which is why i was shut down temporarily for it to cool. But the workers were unable to restart it. A heat exchanger that can be actively cooled requires power, or some sort of free running water similar to a river going through the heat exchanger so it can cool.
@@neurofiedyamato8763 why would it not be able to run continuous operation? Water boils, spins a turbine that sucks in cold seawater to cool the boiling water in the reactor thru a heat exchanger. As long as the reactor has boiling water, the turbine will spin causing the cooling. The boiling water goes away, the turbine stops spinning. Even if it were to start back up, the cooling would begin again.
My understanding is that the backup diesel generators were on the ground floor, so taken out of commission by the flooding, which was against regulation. Another nuclear power plant nearby correctly had its diesel generators on upper floors, so they were able to continue operating, cooling the reactors there without incident. So it all came down to the diesel generators being placed on the wrong floor... such an expensive lesson.
Which tells us that had it not been for that idiotic oversight by TEPCO, the power plant would have been perfectly fine *despite a magnitude 9 earthquake and tsunami*
Its interesting that the backup cooling system on reactor one was working and appears to have been capable of self powering itself, yet was shut off as per standard operating procedure. I would like to know the technical reasons why it needed to be shutoff temporarily.
Most likely to prevent excessive cooldown that would cause advanced metal fatigue of the reactor vessel. If they would have kept it running it would keep the core cool but damage the core zercalloy fuel rods. It's a fine line they have to stay on.
I was under the impression that the heat exchanger was providing too much cooling. Meaning, keeping the core cool, but getting too hot itself, due to it being a closed system with no way to get rid of the heat it's building up other than natural convection. All that heat has to go somewhere. I think that part was just not fully explained.
Very well done video! The sequence to these things always seems to be: Grid shuts down -> Reactors shut off but still need cooling water -> Without external grid power, nothing to pump water -> Diesel generators take over -> Diesel generators run out of fuel or are taken offline for some reason -> Plant melts down. So the biggest problem it seems is lack of power to run the pumps. Seems sort of odd to me - a power plant melting down because of lack of power, the very thing the plant is built to produce? Why can't the power plant, even in a mostly shut down mode and disconnected from the grid, produce it's own power to cool itself without using diesel generators or external power? It's producing heat, which is the problem, I'd think this heat could be converted to (mechanical or electrical) power to run the cooling systems. So the reactor runs it's own cooling system rather than relying on external systems - that should be much more fail-safe, and able to run for a long period of time without external supplies (fuel) or human intervention if designed right. This seems so logical I'm sure engineers who design these plants have thought of it, and there must be some good reason it isn't done, I'd be interested to know what it is.
These days were horror for me... outside beautiful clueless spring weather and on the news this Desaster. I remember standing on a road near my village, looking at the sky and thinking of what happens in Japan... a scene I can’t get out of my head till today.
This video should mention that the sea-water pumps feeding the power plant ITSELF were destroyed by the tsunami, not only most of the diesel power generators. But the situation was even worse: the diesel-generators relied on water-cooling by the very sea water-pumps they were to power, so the remaining power generators stopped working because of the lack of water-cooling.
As I understand it, the generators failed to pump water to cool the reactors. Yet, when looking at pictures of the site, tall cliffs are within a kilometer. Seems a few water storage tanks and manual valves might have prevented this anomaly.
CSX / Richard. I was thinking about an artifical lake at the top of the hill using rainwater to fill it. The Lake would be oneway only, not recirculating. The Lake could have a small charge to use it, so the cost ofbuilding it would be repaid over time.. In an emargency, the lake then would be roped off to the public, valves opened and water gravity fed for many days - more so if there was considerable rainy days. Eother build a heat exchanger with the closed system so the water heats as it goes past the reactor - my preference - or allow there to be a connection to the closed system just in case there is ana issue with the closed system./ or make both available. In fact, you could probably have the lake water run a generator turbine. providing emergency electricity, AND also providing a direct physical geared generator shaft connection to the closed system to provide another pump / circulating system.
I would like to point out that for nearly 50 years these reactors sat there and purred away making power. It took a tsunami of biblical proportion to disrupt power which could have been prevented had they retrofitted the systems. Yes people were hurt... but we drive roads where people are killed on a regular basis, yet we do not call for the elimination of the car or the roadway.
Perry Anderson IKR. Their only backup systems for a massive unforeseen disaster would only last a day or so before catastrophic meltdown. What the fuck lol
The disaster that unfolded here was completely preventable, in my opinion. To this day I still do not understand why auxiliary power was not flown in the first hours to substitute the failed diesel generators and power the cooling pumps. I have no doubt that there were multiple gensets available to the military within 30-minutes flying time. And how hard is it to run a cable and hard-wire a pump motor. In my estimation this disaster was caused by a failure of leadership on many levels.
The test that popped Chernobyl was to guard against what happened at Fukushima. It takes 90 seconds for a diesel generator to get up to speed and they were testing to see if the Reactor could generate enough power to run it's own pumps in the 90 seconds between the loss of grid power and the beginning of diesel power. As we all know the test went catastrophically wrong. Or 'tits up' as we say in the UK.
@@adamw.8579 I thought the problem was mechanical failure in the steam turbines; as they're powered by steam being constantly generated from the heat from the radioactive material and the cooling water, they shouldn't need external electricity.
@@scottcantdance804 the steam turbines hooked up with the generator are "outside" the reactor buildings so the electricity is kind of "external". The issue was that both generators and switching stations were flooded so it was impossible to get the pumps back online with "external" power. They tried connecting external generators brought after the disaster but the flooding prevented the energy from reaching the pumps and getting them to run. Not only should have the backup systems been installed on flood-proof locations, maybe there could be a way to have the batteries use their juice to operate some valves that recirculate the steam into a turbine connected to both an alternator and a turbopump. That way you could generate electricity to run the plant without depending on the diesel generators and even if electricity failed due to flooding the mechanical connection of a driveshaft between turbine and pump would guarantee mechanical pumping even if power generation was not possible.
@@krashd no the problem in chernobyl reactor was somewhere else, you can't have a nuclear accident cause the cooling of the reactor stop (or more precisely, slow down) for 90 sec.... the accident was mainly cause by the fact the control team completely fuck up the gestion of the reaction (combined with some defects of construction of RBMK). first for the test they needed to slow down the reaction, but they fucked it up and slowed the reaction to much. at really low power the reactor get intoxicated with xenon, it is a fission product that have the bad consequence of slowing/stoping the nuclear reaction. in order to avoid this intoxication to stop the reaction (which means, need to remplace all the combustible inside the reactor if its happen, so cost a lot of money and probably the job of the guy that fucked up) they decide to remove almost all control rod, which is more that it is authorized by the constructor (the constructor say that should always remain at least 30 rod, when they only let 3 left). this absurdity, combined with the fact RBMK have a defects of construction that make the reaction a little instable at low power, producing peak of power. This peak make the reactor regain power really fast and as he don't have enough rod in to slow it down the reaction start to be wait to active, and produce to way much heat. When the control team saw that they decide to activate the emergency shutdown, inserting all the rod inside the reactor, but as the heat was already to high, the tube where the rod have to be inserted were deformed by the heat blocking the insertion after 2 meter instead of 17. Then a second defect of construction make it even worst. the botton part of the road (the only portion inserted due to the deformation) is in graphite, a element that moderate the speed of the neutron and increase the power of the reactor making the reaction even stronger!!! at this moment even with a perfectly working cooling system the heat produce by the combustible is just to much, and when its so hot it create a steam explosion (and also probably a hydrogen explosion due to the separation of the oxygen and hydrogen of the water, we are sure for the steam explosion but not for the hydrogen one). This steam explosion destroy the top part of the reactor, letting it reject all radioactive product to the air let the air flowing it, allowing the ignition of graphite due to the temperature, producing a huge fire. This accident was the only time we loose the control of a reaction, and was mainly due to manipulation error, not cooling problem.
An excellent explanation It makes me want to bang my head on the desk. That no one thought about redundancy in such a dangerous process. Clearly, one failure cascaded into another, and no one had ever considered how to provide redundancy, is mind blowing.
To be fair, there was plenty of redundancy built into the system. External power, internal generator backups that could run indefinitely, battery backups that could run for 24 hours, etc. It was a failure to design against a prolonged flooding event that exceeded 10 feet. Certainly a failure of imagination, but it was hardly a failure to design for redundancy.
Paul's CCNA If you think about it, the final protection method - the containment structures - have done their job, unlike Chernobbl which had no containment and was exposed to open air.. With Fukushima we saw no radiation deaths. No increases in cancers.
Short correction to this video. at 2:47 The first barrier is the ceramic pellet which the Uranium, generally in the form of uranium oxide, as it will generally contain the fission fragments, as well as the uranium which is being used as fuel. Therefore in the case of a rod failure, i.e the zirconium sheath breaks, the fission products would still have to break free of the ceramic pellet to become dangerous in the sense that they could the be transported out of the core.
Thank you for this concise and easy to understand explanation of what happened. I started researching this because of the miniseries on Netflix called The Days.
Seems to me this was a poorly designed reactor type. Single redundant backups of each system etc. Confidence in the ability to construct and design these reactors seems akin to the confidence of the builders of the Titanic.
The video shows THE most absurd design flaw of the GE Mark-1 containment BWRs. It points out - "correctly" -- that to avoid over-pressurization and rupture of the containment, the operators had to vent radioactive gases to release that pressure. That negates the original purpose of containment -- which is to keep radioactive contamination INSIDE, and NOT release it to the environment and contaminate the local population. Kinda like "We had to destroy the village to save it" kind of mentality that was used in Vietnam. The "correction" suggested post-Fuku was to install filtered vents, so that the pressure could be released, but the radionuclides contained. THIS RECOMMENDATION WAS MADE BY THE TECHNICAL STAFF OF THE NRC TO THE FULL COMMISSION, AND WAS REJECTED BY 4 OF THE 5 NRC COMMISSIONERS. IT THEREFORE WAS NOT MANDATED TO BE INSTALLED AT THE 23 GE-BWR MK-1S IN THE U.S. And we're supposed to feel "protected" by the regulators?
interesting. So the nuclear reactors here are exactly the same as some in the US? Even after this incident showcasing the problem with radionuclide containment?
I know nothing about nuclear technology, but it seems to me that filters on any vent that could purge radioactive gases into the atmosphere would be a no-brainer?
What have we learned today...... Do not build a nuclear reactor on the coast facing one of the most active fault lines in the world. This was a disaster waiting to happen.
Nuclear power is very efficient and clean. Unfortunately if something goes wrong the potential for catastrophe is significant. When building power plants it is important that we do not cut any corners (for safety reasons). Needless to say, corners were cut here and Japan and the Pacific Ocean is paying for it now.
Japanese journalist Ryūshō Kadota interviewed several hundred people who were involved, and assembled their stories into a nerve-racking account of the disaster, both in and around the reactors. You can find his book 「氏の淵を見た男」 in English titled "On the Brink". To think that those control rooms lay between the reactors! The movie "Fukushima 50" will shortly be released, and should be well worth watching.
what is not mentioned here is that the fuel for Block 3. was in fact MOX , Mixed Oxide, a mixture of U235 and Plutonium 239 . The owners of the plant had , I think, recieved permission to use this very dangerous fuel only shortly before the accident. If this is true then we must presume that the Corium from Block 3. contains About 10 Tonns of Plutonium, can somebody help with more Information as to how much Plutonium is involved ??
I work in aviation so I believe in overkill redundancy. It seems to me like all it would take to prevent this is multiple diesel "submarine" engines to power the generators. Given the plants proximity to water I don't think this is expecting too much.
I was there. Onboard the USS George Washington. We pulled out, deconed, and started hauling food, blankets, PPE, and Medical Supplies to another carrier who took them and distributed them where necessary. Then we went underway again for what seemed like forever, with no idea how long we were going to be out there. Wound up staying out for 79 days after a quick stop in Sasabo.
The sad part is we pretty much solved the issue for cooling nuclear reactors with molten/liquid sodium. They are physically incapable of allowing a runaway nuclear chain reaction as the molten sodium will automatically misaligne the rods once the reaction reaches a specific temperature.
No mention of the fact that the company that owned this reactor issued the workers conducting cleanup operations radiation detectors that were lined internally with lead?
Does anyone know why they shut the valves on the natural convecetion cooling system in reactor 1? They state excessive cooling. This seems like a really odd thing to do if your main objective is to keep things cool in an emegency situation. I'd like to know what the worst case senario is for excessive cooling. I have this odd feeling it is not as bad as thermal run away.
Reactors are large wall thickness metal structures. These structures are subject to heat up and cool down rate limitations to protect them from brittle fracture. Brittle fracture is a sudden failure mode versus elastic failure which results in slow yielding of the material. In large wall metal structures the inner and outer surfaces heat (or cool) at different rates due to the large mass. The temperature differences drive metal to expand (or contract) which adds stresses that can can exceed the strength of the material. For this reason, rates of temperature change are placed on the system to protect it. Operators primary job is ensure the system integrity is protected at all times, so they follow strict rules on temperature change rates.
@@luciolalazilia2189 it was not a stupid design in its concept its a safety system if some thing happends you dont know if its the reactor or the cooling system itself thats got damage!! the problem was the lag of knowing that is whas closed and the pressursensor first they didnt had energy so they used car batterys to run most importen ssystem and that took some time to do then the pressure sensor showed that the cooling system did not run and they opend the valve and that was the point when shit hits the fan!!!! in the time the system was off most of the water in reactor 1 evaporated like 90% steam, 10 water they open the backup system and watches the sensor data that showed it was running its fine but in fakt the pumped all the water inside the overheated core and lost the last resort of water becaues it also evaporate the back upsystem cant keep upat this late point and they didnt know that they where running there backup system on stream not water it was like pissing in a wildfire
In a German Documentation they have shown that the control room was cut off the power lines for several hours without any Information and measurements or sensor signals. Then, with candle light the Japanese read the manual and came at the last pages to the point that the valve of the cooling system had to be opened manually, without electricity. Then, they used car batteries from the car park to re --power the control panel. In the meantime the sensors had all melted. When they finally managed to switch on the controls again the values displayed were all completely wrong. In the erroneous believe that the temperature was low enough they closed the valve again. Then, they were totally surprised by the hydrogen explosion which destroyed the upper reactor portion ....
I still can’t understand why back up generators haven’t been isolated on same place higher or in full waterproof rooms… If they haven’t failed at first place everything would be just in boarders of cosmetics damages of the building it self without compromising reactors themselves…
So this was published in 2012, just 15 months after the accident. The situation was not yet well understood back then. And a lot has happened in the 7 years since then. At 6 minutes the video says it is not known if the steel shell or the concrete enclosure were pierced. Is there a link to a more up-to-date video ???
Apparently the plant manager was under strict orders from his corporate superiors in Tokyo NOT to inject seawater because it would damage their expensive equipment. He ignored them and thus prevented a total multi-reactor meltdown that would've been the equivalent of several Chernobyls.
Reactor buildings should adopt an onion or Russian doll design, with containment and a cooling jacket at each layer. Nuclear power is vital to modern societies and when managed properly is very safe. We need disaster proofing.
What a cluster fuck of design. Knowing it was a earthquake zone and tsunami probably zone having multiple off site generators to ensure power for cooling systems would be a obvious idea. This is an example of cost and profit being more important then safety in danger zones. The fact we (globally) still don't know how bad the damage is to the reactors shows how little we know and control nuclear power plants.
What happens to the radioactive vapor released in the atmosphere? I know it gets dilluted in the atmosphere, but still its possible that someone, somewhere will inhale one of these radioactive molecules and give them cancer, right? And since it does not get absorb by the body, it gets released when that person exhale and this radioactive molecule will then again find it's next victim to give him cancer. Right? Based on my understanding, low level waste last at least 30yrs? Are those radioactive vapors high level waste since it probably not came from the cooling water?
Keep in mind that the atmosphere is pretty big, and gaseous radioactive elements will disperse over a large area. The more dilute, the less harm it can do. If those radioactive elements have short half-lives (which many of them do) they will emit some particles and then stop being radioactive. You need a lot more than a single radioactive atom to get cancer, unless you are literally the unluckiest person in the world. The Fukushima accident was very bad, and clearly mistakes were made in the engineering of the power plant. But keep in mind that twenty thousand people died because of the tsunami. Yet you don't see calls for people to abandon the shore and move far inland. This is despite the fact that tsunamis WILL happen again, and they are very difficult to predict. So perhaps it doesn't make sense to abandon our safest (in terms of lives lost per megawatt-hour) energy source.
A big thank you to the guys who cleaned that stuff and were on site after the accident. Unlike in Chernobyl the know the risks but despite that they are playing there role. Japanese fast action is impressive. Thanks to the IRSN for this short but focused video, very well made.
To contain the molten radioactive fuel, why is there not a structure underneath that would divide the material into separate compartments to control the chain reaction? There is probably a reason why this hasn't been used but I cant think of one.
There are monthly updates on the site, are you expecting to be mailed updates? People always say "Funny how..." before they have even bothered to even look for something.
It is possible to generate power through nuclear fission doesn't have this problem, but it's a very different type of technology. A Thorium molten salt reactor is naturally self-limiting.
So...this design allows irradiated water from the core to mix with the feed water? I thought all reactors had a separate cooling water (feed water) loop that was isolated from the radioactive heated water that went through a steam controller that creates the steam. It doesn't make much sense to have irradiated cooling water. At 2:00 "A BWR has only one single system combining feed water and steam." At Three Mile Island, there were heat exchangers but the two loops were isolated from each other...heated core water and cooling feed water....the heat from the feed water went out to the huge cooling towers and when cooled was recirculated back to the heat exchangers. This Fukushima design looks like it is combining radioactive steam and feed water. Seems odd.
I read somewhere about reactor designs that are passively (don't remember the exact term) safe - meaning that if all safety systems fail, they will still not be a threat to the environment. I'm guessing these reactors are an older design?
Moral of the story... if you are going to build nuclear power plants along the coast of Japan, do more to protect the backup power generators. In other words, prepare for the worst case scenerio (which the engineers obviously didn't do).
We live in a world of "Lowest Bid wins the contract" - You get what you paid for. Technical excellence - determined by an independent authority (Not a simple regulatory minimum) should be the only criteria for contract awards were failure means large scale destruction of life/environment.
@12:13, you see bubbles in the Reactor Pool, why are they there? The video doesnt give a date though. EDIT: Saw the film date at the end, Feb 2012. So I guess cooling maybe?
This is the first time I've totally understood exactly what happened- 8 years after the fact. Thank you, IRSN
Yes
The best part of this story is that all of the older people in Japan stepped up to work on cleanup so the younger people would not have to suffer . Cancer from radiation poisoning takes many years to kill you and they figured they were already old so why not save the young from this fate . Faith in humanity still stands tall !
Scott Odonahoe in Japan maybe. In America they’d get the Guards or Army to go in and clear the debris. Like they’ve done before
"Cancer from radiation poisoning takes many years to kill you"
Radiation poisoning assumes you managed to swallow something radioactive. Very high level radiation exposure usually either kills you or (temporarily) knocks out your immune system, making you susceptable to dying of the common cold. There's a body of evidence that it doesn't so much cause cancer (which are generally caused by chemical precursors) but the weakened immune system allows cancers which are already present to get a foothold.
The 2 strong pointers about most radiation exposure not being cancerous are simple: Aircrew (who get more occupational high level exposure than any other group and aren't exactly dropping like flies) and smokers (who accumulate significant quantities of polonium in their lungs and yet take decades to develop lung cancers - which actually seem to be triggered by exposure to the polonium breakdown products (such as lead) rather than the actual radiation)
That said, water-moderated reactors are inherently dangerous(*)(**) and should be banned - they're so dangerous that the guy who designed and built the first one was deeply disturbed by their use in civil power plants and used the nuclear aircraft project to develop a far safer alternative which is completely walk-away safe - molten salt reactors. These were tested and operated in the 1960s but R&D was shut down for political reasons in 1972 by that nice mr Nixon chap.
(*) Nuclear power is 300,000 times safer than coal fired power and in fact is statistically safer than every other form of electricity generation - but (read below) it could be a few thousand times safer still and generate less than 1% of the tiny amount of waste(***) it does.
(**) without radioactives in the mix, a steam explosion in a nuclear power plant is just that - a steam explosion. Mixing water and nuclear materials is a fundamentally bad idea as it means that things can escape to the biosphere - furthermore, _every_ civil nuclear accident so far (even Chernobyl) has involved+been exacerbated by water and wouldn't have been possible in a molten salt design.
Molten metal moderators such as sodium seem like a good idea on paper, but no matter how much the engineers claim they know what they're doing and "it won't catch fire, honest", they've caught fire - and even a non-nuclear-loop sodium fire is bad news as you can see if you read the reports of what happened at Monju.
(***) The entire high level nuclear waste output of a 800MW nuclear reactor over a 60 year lifespan will fit comfortably in an olympic size swimming pool and be safe to handle in about 350-400 years (NOT 20,000). As-is, it also happens to be quite usable sidestream fuel for those mollten salt reactor designs mentioned above.
Faith in humanity my ass. If that were the case shut down all nuclear reactors World wide. With so many other sources for energy there are far better and much safer to you not to mention cheaper to build 2 harness the energy
Chris Block Can we assume that you are happy for people in the oil and gas industry or mining to take physical risks on your behalf yet the negligible risk of radiological contamination is too much for you, being unwilling to share the risks involved in being resident in an advanced society? Yes Japan is a terrible place for a nuclear power station ha ha.
Faith in humanity? What a shitty way to treat senior citizens.
Great video. All the necessary details and easy to understand. I would like news reports to be like this, not the very superficial coverage that is usually available to the public.
Andrés Mlinar there are no news reports anymore. It’s “opinion” of news reports. #Ratings
Andres M. Yes, I agree. Now we need a dialogue page maintained by GE the designer of the initial Fukushima system. The dialogue page will allow for sensible discussion and free exchange of ideas for resolving this global disaster. GE is defensively shedding assets and stock value as we speak. This is to the shame of America.
GE has been run by bean counters and various business cocks rather than engineers for some time now - and that is why it is failing, not the Fukushima disaster.
The fault lies with the plant owners, who had insufficient backups.
Don’t agree, it’s missing the key information. The impact on human and natural live, they don’t even detailed all the contaminated water pumped to the sea...
@@SVQGOT You're correct. With that said, in the context of what they were discussing, this video primarily focused on the Engineering failure. If it was simply a news video, I think more focus would have went to the effects that spread out from ground zero. In this case, the purpose was to explain the situation purely from within Fukushima, from the viewpoint of Engineers. That's why, I believe, they left out some of the information about the broader situation this disaster left.
You are dealing with something that has already occured on this planet before
I understand that reference
Well that's not great but it's not horrifying
Certified AZ-5 button moment
The Core was not exposed and Scherbina did not see the graphite.
8:08 The building is actually *designed* that way, so that if there's a hydrogen explosion in the superstructure, the walls of the structure actually give way and are blown apart, and thus the explosion doesn't get to damage the containment below. The design did its job as it was supposed to.
This video also show that had it not been for a design flaw with the generators (something TEPCO knew as far back as 1990) the power plant would have been able to keep operating even after an insane earthquake and tsunami.
Always make a backup of your backups of your backups of your backups of your backups.......
As a Result, New Backup called Fukushima Response Action Plan (FRAP) is added in new and old plants as well.
It seems to me that in a country prone to earthquakes and the resulting tsunamis, it might've been prudent to elevate the diesel generators off the ground so that they couldn't flood.
You would think so... sufficed to say this was an entirely preventable disaster.
They were - just not high enough. The problem was that they were built with Tsunamis in mind, but this one was over (I don't remember exact numbers) 4 m higher than highest anticipated.
Or not to store the batteries...IN THE BASEMENT
Or how about the brilliant location of putting this plant directly on the coast line... How did that get approved?
@@AtimatikArmy unfortunately you need large bodies of water to help with the cooling. Since Japan is an island, ocean water was the logical way to go.
This is the clearest explanation of reactor operations and the Fukushima accident that I've ever seen on UA-cam or the internet. I used to work at a BWR with exactly the same type of containment and ECCS, so I was interested in the slow, progressive failure of the various pieces of the ECCS, containment, etc. I especially appreciated the calm, detailed explanations. In my years of working at the BWR plant, I never, ever heard an accurate news report on events at the plant. The IRSN deserves praise for presenting the facts of the accident and its aftermath.
A useful improvement on this video would be a report on radiation exposure for the various teams. Cycling 20,000 people through the wrecked plant sure sounds like many people reached their occupational exposure limit. Occupational exposure limits have changed since I first trained as a Navy Nuc and are much lower than they used to be.
This is what happens when you let TEPCO run nuclear power plants. They knew that the seawall at the Fukushima Daiichi nuclear power plant wasn't high enough, yet they still did stupid things like put the emergency generators in the basement of all places. The Onagawa nuclear power plant which was closer to the epicenter survived perfectly intact thanks to its 14 meter seawall.
But the proposals you cite would have cost money and cut into their profits! :(
Enigmatic Destroyer uuuuuytrew
yes point!
If what you say is true, I hope that they suffer criminal liabilities for their negligence.
Guillermo Guille Grow up? Grow up? What kind of sociopath are you?
I wish Japan had at the ready the nuclear power expertise available from this comment section.
No one asked me
😂
Massive respect to the guys at Fukushima for their work. Not so much for the upper management though.
This was a very good overview of the disaster. There were a few places where I wish the narrator went into a bit more detail, but overall it was a very interesting and informative watch.
They just started removing nuclear fuels 04-15-2019 and it is expected to take 2 years. The one from reactor 3 will be the hardest and they won’t start that until 2021 reports say
TL:DW: Whoever decided that building the backup generators on ground level, with no protective walls, on the coast, of a country prone to earthquakes and tsunamis, is directly and solely responsible for the entire meltdown and everything that resulted from it. End of story.
well the thing is that japans entire coast line dropped 4 ft during the earthquake. lots of seawalls were rendered useless as a result.
It is a rarity that someone(/s) of incredible intelligence can explain an intricate concept in a manner so easily understood - even by someone as blunt as I am!
Thank you.
It seems that elevating and distancing their backup power sources would've at least reduced the risk of reactor damage, and at most would've prevented the disaster completely. Unlike other power plants, a nuclear plant must be able to maintain it's own power supply at any cost, and for a long duration.
In most situations, that was indeed the case. Unfortunately, they didn't seem to consider a tsunami that could breach the sea wall, and caused a common mode failure when it disabled all 13 diesel backup generators. True though - in hindsight, said generators should have probably been situated on higher ground.
@@WaterCrane First construction plans actually focused on that security issue..
It was cheaper installing the backup diesel generators closer to the plant, but at lower level making flooding a risk..
A Japanese engineer describes this failure on a documentary available on UA-cam.. He was ignored/silenced!
On 30 October 1991, Seawater leaked in the reactor's basement and one of two backup generators failed. An engineer informed his superiors of the possibility that a tsunami could damage the generators.
en.wikipedia.org/wiki/Fukushima_Daiichi_nuclear_disaster#1991:_Backup_generator_of_Reactor_1_flooded
TOSHIO KIMURA (translated): I asked my boss back in the late '90s what would happen if a tsunami hit the Fukushima reactors. I said surely a meltdown will happen. He said 'Kimura, you are right'. But it was made clear that the issue of a big tsunami was taboo. A few years later I quit the company because of its culture of cover-ups.
www.abc.net.au/pm/content/2011/s3240171.htm
@Joe Al our large corporations are getting just as bad, especially with the trump culture of deregulation and bought/legally enforced silence.
This is the best video I've seen on this disaster, and by far.
And some say being a mother is the hardest job
Have you ever seen a toddler have a meltdown in a supermarket. I'd take dealing with an unstable reactor any day. At least you can shut off the alarm.
The cleanup workers were heroic. They paid the price for management incompetence.
None have died from radiation exposure.
@@dav4x487unfortunately that's not true. One died of lung cancer in 2018 from his exposure. Very sad
Excellent, accurate and technically reliable documentary. Thank you.
Yes it is. The best way of a 'passive' cooling was the heat exchanger that relied on gravity and steam convection. But because the heat exchanger is a closed cycle, it can't maintain continuous operation which is why i was shut down temporarily for it to cool. But the workers were unable to restart it.
A heat exchanger that can be actively cooled requires power, or some sort of free running water similar to a river going through the heat exchanger so it can cool.
@@neurofiedyamato8763 why would it not be able to run continuous operation? Water boils, spins a turbine that sucks in cold seawater to cool the boiling water in the reactor thru a heat exchanger. As long as the reactor has boiling water, the turbine will spin causing the cooling. The boiling water goes away, the turbine stops spinning. Even if it were to start back up, the cooling would begin again.
This is the only video which does really explain all the open questions that I had. Thank you.
The world's most dangerous giant kettle
My understanding is that the backup diesel generators were on the ground floor, so taken out of commission by the flooding, which was against regulation. Another nuclear power plant nearby correctly had its diesel generators on upper floors, so they were able to continue operating, cooling the reactors there without incident. So it all came down to the diesel generators being placed on the wrong floor... such an expensive lesson.
Which tells us that had it not been for that idiotic oversight by TEPCO, the power plant would have been perfectly fine *despite a magnitude 9 earthquake and tsunami*
Its interesting that the backup cooling system on reactor one was working and appears to have been capable of self powering itself, yet was shut off as per standard operating procedure. I would like to know the technical reasons why it needed to be shutoff temporarily.
Most likely to prevent excessive cooldown that would cause advanced metal fatigue of the reactor vessel. If they would have kept it running it would keep the core cool but damage the core zercalloy fuel rods. It's a fine line they have to stay on.
I was under the impression that the heat exchanger was providing too much cooling. Meaning, keeping the core cool, but getting too hot itself, due to it being a closed system with no way to get rid of the heat it's building up other than natural convection. All that heat has to go somewhere. I think that part was just not fully explained.
Very well done video! The sequence to these things always seems to be: Grid shuts down -> Reactors shut off but still need cooling water -> Without external grid power, nothing to pump water -> Diesel generators take over -> Diesel generators run out of fuel or are taken offline for some reason -> Plant melts down. So the biggest problem it seems is lack of power to run the pumps. Seems sort of odd to me - a power plant melting down because of lack of power, the very thing the plant is built to produce? Why can't the power plant, even in a mostly shut down mode and disconnected from the grid, produce it's own power to cool itself without using diesel generators or external power? It's producing heat, which is the problem, I'd think this heat could be converted to (mechanical or electrical) power to run the cooling systems. So the reactor runs it's own cooling system rather than relying on external systems - that should be much more fail-safe, and able to run for a long period of time without external supplies (fuel) or human intervention if designed right. This seems so logical I'm sure engineers who design these plants have thought of it, and there must be some good reason it isn't done, I'd be interested to know what it is.
These days were horror for me...
outside beautiful clueless spring weather and on the news this Desaster.
I remember standing on a road near my village, looking at the sky and thinking of what happens in Japan... a scene I can’t get out of my head till today.
This video should mention that the sea-water pumps feeding the power plant ITSELF were destroyed by the tsunami, not only most of the diesel power generators. But the situation was even worse: the diesel-generators relied on water-cooling by the very sea water-pumps they were to power, so the remaining power generators stopped working because of the lack of water-cooling.
As I understand it, the generators failed to pump water to cool the reactors. Yet, when looking at pictures of the site, tall cliffs are within a kilometer. Seems a few water storage tanks and manual valves might have prevented this anomaly.
CSX / Richard. I was thinking about an artifical lake at the top of the hill using rainwater to fill it.
The Lake would be oneway only, not recirculating.
The Lake could have a small charge to use it, so the cost ofbuilding it would be repaid over time..
In an emargency, the lake then would be roped off to the public, valves opened and water gravity fed for many days - more so if there was considerable rainy days.
Eother build a heat exchanger with the closed system so the water heats as it goes past the reactor - my preference - or allow there to be a connection to the closed system just in case there is ana issue with the closed system./ or make both available.
In fact, you could probably have the lake water run a generator turbine. providing emergency electricity, AND also providing a direct physical geared generator shaft connection to the closed system to provide another pump / circulating system.
Good Video, focusing on the facts
Graham Ariss 3v
Graham Ariss gvveee
Really? No even one guy died? Or is not an important fact?
Nicolas FERNANDEZ only one person died due to the disaster and that’s because of radiation
THE US was testing a mega nuclear bomb and thats what caused the earthquake that caused Fuku!
All constructions like bridges have to be designed with 300% reserve. Tsunami durability of a nuclear plant can be designed with 30% reserve.
If I had UA-cam in my high school, i would’ve aced all my physics exams
I would like to point out that for nearly 50 years these reactors sat there and purred away making power. It took a tsunami of biblical proportion to disrupt power which could have been prevented had they retrofitted the systems. Yes people were hurt... but we drive roads where people are killed on a regular basis, yet we do not call for the elimination of the car or the roadway.
there doesn't seem to be much redundancy
Perry Anderson IKR.
Their only backup systems for a massive unforeseen disaster would only last a day or so before catastrophic meltdown. What the fuck lol
Some of these reactors didn't even have backup generators or pumps? Not that they seemed to do much good. What the hell are engineers doing?
Since this accident I always was asking why did they build 6 reactors in line and very close to each other????
The disaster that unfolded here was completely preventable, in my opinion. To this day I still do not understand why auxiliary power was not flown in the first hours to substitute the failed diesel generators and power the cooling pumps. I have no doubt that there were multiple gensets available to the military within 30-minutes flying time. And how hard is it to run a cable and hard-wire a pump motor. In my estimation this disaster was caused by a failure of leadership on many levels.
If you ask me, it's pretty ironic than a power plant meltsdown cuz it doesn't have energy
More costs and every reactor should have own self sustained power plant. They had energy but not eletricity.
The test that popped Chernobyl was to guard against what happened at Fukushima. It takes 90 seconds for a diesel generator to get up to speed and they were testing to see if the Reactor could generate enough power to run it's own pumps in the 90 seconds between the loss of grid power and the beginning of diesel power. As we all know the test went catastrophically wrong. Or 'tits up' as we say in the UK.
@@adamw.8579 I thought the problem was mechanical failure in the steam turbines; as they're powered by steam being constantly generated from the heat from the radioactive material and the cooling water, they shouldn't need external electricity.
@@scottcantdance804 the steam turbines hooked up with the generator are "outside" the reactor buildings so the electricity is kind of "external". The issue was that both generators and switching stations were flooded so it was impossible to get the pumps back online with "external" power. They tried connecting external generators brought after the disaster but the flooding prevented the energy from reaching the pumps and getting them to run.
Not only should have the backup systems been installed on flood-proof locations, maybe there could be a way to have the batteries use their juice to operate some valves that recirculate the steam into a turbine connected to both an alternator and a turbopump. That way you could generate electricity to run the plant without depending on the diesel generators and even if electricity failed due to flooding the mechanical connection of a driveshaft between turbine and pump would guarantee mechanical pumping even if power generation was not possible.
@@krashd no the problem in chernobyl reactor was somewhere else, you can't have a nuclear accident cause the cooling of the reactor stop (or more precisely, slow down) for 90 sec.... the accident was mainly cause by the fact the control team completely fuck up the gestion of the reaction (combined with some defects of construction of RBMK). first for the test they needed to slow down the reaction, but they fucked it up and slowed the reaction to much. at really low power the reactor get intoxicated with xenon, it is a fission product that have the bad consequence of slowing/stoping the nuclear reaction. in order to avoid this intoxication to stop the reaction (which means, need to remplace all the combustible inside the reactor if its happen, so cost a lot of money and probably the job of the guy that fucked up) they decide to remove almost all control rod, which is more that it is authorized by the constructor (the constructor say that should always remain at least 30 rod, when they only let 3 left). this absurdity, combined with the fact RBMK have a defects of construction that make the reaction a little instable at low power, producing peak of power. This peak make the reactor regain power really fast and as he don't have enough rod in to slow it down the reaction start to be wait to active, and produce to way much heat. When the control team saw that they decide to activate the emergency shutdown, inserting all the rod inside the reactor, but as the heat was already to high, the tube where the rod have to be inserted were deformed by the heat blocking the insertion after 2 meter instead of 17. Then a second defect of construction make it even worst. the botton part of the road (the only portion inserted due to the deformation) is in graphite, a element that moderate the speed of the neutron and increase the power of the reactor making the reaction even stronger!!! at this moment even with a perfectly working cooling system the heat produce by the combustible is just to much, and when its so hot it create a steam explosion (and also probably a hydrogen explosion due to the separation of the oxygen and hydrogen of the water, we are sure for the steam explosion but not for the hydrogen one). This steam explosion destroy the top part of the reactor, letting it reject all radioactive product to the air let the air flowing it, allowing the ignition of graphite due to the temperature, producing a huge fire.
This accident was the only time we loose the control of a reaction, and was mainly due to manipulation error, not cooling problem.
Very informative. The 3D rendering helps a lot. Thank you.
4:32 >> "Heat exchanger shutoff due to excessive cooling" - anyone can explain the logic behind this?
An excellent explanation
It makes me want to bang my head on the desk. That no one thought about redundancy in such a dangerous process. Clearly, one failure cascaded into another, and no one had ever considered how to provide redundancy, is mind blowing.
To be fair, there was plenty of redundancy built into the system. External power, internal generator backups that could run indefinitely, battery backups that could run for 24 hours, etc. It was a failure to design against a prolonged flooding event that exceeded 10 feet. Certainly a failure of imagination, but it was hardly a failure to design for redundancy.
...and it was all government-approved.
They are here to help us... right.
Paul's CCNA If you think about it, the final protection method - the containment structures - have done their job, unlike Chernobbl which had no containment and was exposed to open air.. With Fukushima we saw no radiation deaths. No increases in cancers.
Blows my mind that there wasn't some sort of passive mechanism to cool the reactor continuously. What a terrible design.
The heat exchanger IS a passiv component that doesn't need any power.
there is a emergency condencer but the valve was shut, then they opened it, and shut it again, because they thought it will break without water...
@@xSteheraanx for 10 hours only... and did u warch the video with understandig?
Like was said, there was one.
Short correction to this video. at 2:47 The first barrier is the ceramic pellet which the Uranium, generally in the form of uranium oxide, as it will generally contain the fission fragments, as well as the uranium which is being used as fuel. Therefore in the case of a rod failure, i.e the zirconium sheath breaks, the fission products would still have to break free of the ceramic pellet to become dangerous in the sense that they could the be transported out of the core.
Thank you for this concise and easy to understand explanation of what happened. I started researching this because of the miniseries on Netflix called The Days.
Seems to me this was a poorly designed reactor type. Single redundant backups of each system etc. Confidence in the ability to construct and design these reactors seems akin to the confidence of the builders of the Titanic.
More costs less profit, money drives this world.
Things built by flawed creatures always will have flaws in their design, it just takes a bit of courage to admit it ...
Well, what do you expect from 1970s nuclear reactors. They should have been long replaced by more modern reactors
The video shows THE most absurd design flaw of the GE Mark-1 containment BWRs. It points out - "correctly" -- that to avoid over-pressurization and rupture of the containment, the operators had to vent radioactive gases to release that pressure. That negates the original purpose of containment -- which is to keep radioactive contamination INSIDE, and NOT release it to the environment and contaminate the local population. Kinda like "We had to destroy the village to save it" kind of mentality that was used in Vietnam.
The "correction" suggested post-Fuku was to install filtered vents, so that the pressure could be released, but the radionuclides contained. THIS RECOMMENDATION WAS MADE BY THE TECHNICAL STAFF OF THE NRC TO THE FULL COMMISSION, AND WAS REJECTED BY 4 OF THE 5 NRC COMMISSIONERS. IT THEREFORE WAS NOT MANDATED TO BE INSTALLED AT THE 23 GE-BWR MK-1S IN THE U.S.
And we're supposed to feel "protected" by the regulators?
interesting. So the nuclear reactors here are exactly the same as some in the US? Even after this incident showcasing the problem with radionuclide containment?
The answer to all of this is money. The company responsible should not exist anymore.
I know nothing about nuclear technology, but it seems to me that filters on any vent that could purge radioactive gases into the atmosphere would be a no-brainer?
Reactor 3 has a different type of explosion than the other ones.
This is the most compressive video about Fukushima's Nuclear Reactor accident! Thsnk you sir
What have we learned today......
Do not build a nuclear reactor on the coast facing one of the most active fault lines in the world.
This was a disaster waiting to happen.
This film is a great addition to the The Days movie, thank you very much!
8:03 Provided there is enough energy to start the reaction as well.
Nuclear power is very efficient and clean. Unfortunately if something goes wrong the potential for catastrophe is significant. When building power plants it is important that we do not cut any corners (for safety reasons). Needless to say, corners were cut here and Japan and the Pacific Ocean is paying for it now.
Who else is watching this in 2019?
2025 bruv
very detail explanation, this is still the best video today.
Japanese journalist Ryūshō Kadota interviewed several hundred people who were involved, and assembled their stories into a nerve-racking account of the disaster, both in and around the reactors.
You can find his book 「氏の淵を見た男」 in English titled "On the Brink".
To think that those control rooms lay between the reactors!
The movie "Fukushima 50" will shortly be released, and should be well worth watching.
what is not mentioned here is that the fuel for Block 3. was in fact MOX , Mixed Oxide, a mixture of U235 and Plutonium 239 . The owners of the plant had , I think, recieved permission to use this very dangerous fuel only shortly before the accident. If this is true then we must presume that the Corium from Block 3. contains About 10 Tonns of Plutonium, can somebody help with more Information as to how much Plutonium is involved ??
I work in aviation so I believe in overkill redundancy.
It seems to me like all it would take to prevent this is multiple diesel "submarine" engines to power the generators.
Given the plants proximity to water I don't think this is expecting too much.
A submarine diesel is no different to the diesels they used, neither will work when literally flooded.
watching this after watching "The Days". Really good video of explaining what happened. Wishing there was an update of the current situation.
8:05 "Hydrogen reacts violently with air". Umm no, hydrogen and air in combination are inert unless a source of ignition is present.
I think inside a nuclear reactor is hot enough for ignition, which isn't set in stone and is based on pressure.
I was there. Onboard the USS George Washington. We pulled out, deconed, and started hauling food, blankets, PPE, and Medical Supplies to another carrier who took them and distributed them where necessary. Then we went underway again for what seemed like forever, with no idea how long we were going to be out there. Wound up staying out for 79 days after a quick stop in Sasabo.
And we lived happily ever after.
calculating the price of all this, counting the amount of energy those reactors were able to produce, would solar energy be cheaper?
Only with a Dyson Swarm but humanity waste most of its time with short term political issues than with big advances.
The sad part is we pretty much solved the issue for cooling nuclear reactors with molten/liquid sodium. They are physically incapable of allowing a runaway nuclear chain reaction as the molten sodium will automatically misaligne the rods once the reaction reaches a specific temperature.
No mention of the fact that the company that owned this reactor issued the workers conducting cleanup operations radiation detectors that were lined internally with lead?
Someone tell me WHY THE FUCK Fukushima melts, and Onagawa NPP - being closer to fault - remains virtually undamaged?
Does anyone know why they shut the valves on the natural convecetion cooling system in reactor 1? They state excessive cooling. This seems like a really odd thing to do if your main objective is to keep things cool in an emegency situation. I'd like to know what the worst case senario is for excessive cooling. I have this odd feeling it is not as bad as thermal run away.
Reactors are large wall thickness metal structures. These structures are subject to heat up and cool down rate limitations to protect them from brittle fracture. Brittle fracture is a sudden failure mode versus elastic failure which results in slow yielding of the material.
In large wall metal structures the inner and outer surfaces heat (or cool) at different rates due to the large mass. The temperature differences drive metal to expand (or contract) which adds stresses that can can exceed the strength of the material. For this reason, rates of temperature change are placed on the system to protect it. Operators primary job is ensure the system integrity is protected at all times, so they follow strict rules on temperature change rates.
They did not know the wave was incoming true but it was an incredibly thoughtless thing to do, unquestioning compliance as always burns fingers.
@@scottkelley1558 a good answer to a good question
@@luciolalazilia2189 it was not a stupid design in its concept its a safety system
if some thing happends you dont know if its the reactor or the cooling system itself thats got damage!!
the problem was the lag of knowing that is whas closed and the pressursensor
first they didnt had energy so they used car batterys to run most importen ssystem and that took some time to do
then the pressure sensor showed that the cooling system did not run and they opend the valve
and that was the point when shit hits the fan!!!!
in the time the system was off most of the water in reactor 1 evaporated like 90% steam, 10 water
they open the backup system and watches the sensor data that showed it was running its fine
but in fakt the pumped all the water inside the overheated core and lost the last resort of water becaues it also evaporate
the back upsystem cant keep upat this late point and they didnt know that they where running there backup system on stream not water
it was like pissing in a wildfire
In a German Documentation they have shown that the control room was cut off the power lines for several hours without any Information and measurements or sensor signals. Then, with candle light the Japanese read the manual and came at the last pages to the point that the valve of the cooling system had to be opened manually, without electricity. Then, they used car batteries from the car park to re --power the control panel. In the meantime the sensors had all melted. When they finally managed to switch on the controls again the values displayed were all completely wrong. In the erroneous believe that the temperature was low enough they closed the valve again. Then, they were totally surprised by the hydrogen explosion which destroyed the upper reactor portion ....
Why was the heat exchanger shut off at 4:33? What is "excessive cooling" in such a situation?
Thanks for a simple and graphic description of the disaster.
I still can’t understand why back up generators haven’t been isolated on same place higher or in full waterproof rooms…
If they haven’t failed at first place everything would be just in boarders of cosmetics damages of the building it self without compromising reactors themselves…
They are a remarkably resilient and stoic people. Still I feel very sorry that this happened to them.
So this was published in 2012, just 15 months after the accident. The situation was not yet well understood back then. And a lot has happened in the 7 years since then. At 6 minutes the video says it is not known if the steel shell or the concrete enclosure were pierced. Is there a link to a more up-to-date video ???
There's a special place in heaven for the people that loose their lives fighting to keep disasters like these from reaching their full potential.
Apparently the plant manager was under strict orders from his corporate superiors in Tokyo NOT to inject seawater because it would damage their expensive equipment. He ignored them and thus prevented a total multi-reactor meltdown that would've been the equivalent of several Chernobyls.
at 4:30 , why was excessive cooling a bad thing? Was it because they wouldn't be able to restart the reactor?
Yes. Fukushima reactor was a type with negative void coefficient
Reactor buildings should adopt an onion or Russian doll design, with containment and a cooling jacket at each layer. Nuclear power is vital to modern societies and when managed properly is very safe. We need disaster proofing.
I have great faith in the ability of Japanese scientists and workers of learning from this accident and solving it with style.
what kind of resin do they spray ? some sort of boron resin I'm guessing
Cadmium is even good neutron suppressor.
What a cluster fuck of design. Knowing it was a earthquake zone and tsunami probably zone having multiple off site generators to ensure power for cooling systems would be a obvious idea. This is an example of cost and profit being more important then safety in danger zones. The fact we (globally) still don't know how bad the damage is to the reactors shows how little we know and control nuclear power plants.
Cutting funds and so called "calculated risk". This shall not have place in nuclear engineering.
What happens to the radioactive vapor released in the atmosphere? I know it gets dilluted in the atmosphere, but still its possible that someone, somewhere will inhale one of these radioactive molecules and give them cancer, right? And since it does not get absorb by the body, it gets released when that person exhale and this radioactive molecule will then again find it's next victim to give him cancer. Right?
Based on my understanding, low level waste last at least 30yrs? Are those radioactive vapors high level waste since it probably not came from the cooling water?
Keep in mind that the atmosphere is pretty big, and gaseous radioactive elements will disperse over a large area. The more dilute, the less harm it can do. If those radioactive elements have short half-lives (which many of them do) they will emit some particles and then stop being radioactive. You need a lot more than a single radioactive atom to get cancer, unless you are literally the unluckiest person in the world.
The Fukushima accident was very bad, and clearly mistakes were made in the engineering of the power plant. But keep in mind that twenty thousand people died because of the tsunami. Yet you don't see calls for people to abandon the shore and move far inland. This is despite the fact that tsunamis WILL happen again, and they are very difficult to predict. So perhaps it doesn't make sense to abandon our safest (in terms of lives lost per megawatt-hour) energy source.
Why cant see the two replies here?
I would like to see an update as to how the situation is today
A big thank you to the guys who cleaned that stuff and were on site after the accident. Unlike in Chernobyl the know the risks but despite that they are playing there role. Japanese fast action is impressive.
Thanks to the IRSN for this short but focused video, very well made.
What a comprehensive and informative video. Well done.
So is reactor #2 still leaking radiation into the seawater?
People in charge of cleanup say that it is not poisoning water but independent scientists say otherwise.
To contain the molten radioactive fuel, why is there not a structure underneath that would divide the material into separate compartments to control the chain reaction? There is probably a reason why this hasn't been used but I cant think of one.
funny how there hasnt been an update in 6 years....
There are monthly updates on the site, are you expecting to be mailed updates? People always say "Funny how..." before they have even bothered to even look for something.
The world doesn't want to know...
Thank you on this explanation and diagrams used for this video. Very well done!
funny how such powerful tool that makes tons of energy, yet they dont have a back up for its back up.
Good info. I dont know if it covers all but still makes it understanding a bit.
Is it really that difficult to design a system that passively cools down once shutdown occurs?
Yes.
you need active cooling for a computer CPU how are you going to passively cool a NUCLEAR REACTOR?
It is possible to generate power through nuclear fission doesn't have this problem, but it's a very different type of technology. A Thorium molten salt reactor is naturally self-limiting.
Difficulty is not the problem. Size and money constraints drive the decisions.
So...this design allows irradiated water from the core to mix with the feed water?
I thought all reactors had a separate cooling water (feed water) loop that was isolated from the radioactive heated water that went through a steam controller that creates the steam.
It doesn't make much sense to have irradiated cooling water.
At 2:00 "A BWR has only one single system combining feed water and steam."
At Three Mile Island, there were heat exchangers but the two loops were isolated from each other...heated core water and cooling feed water....the heat from the feed water went out to the huge cooling towers and when cooled was recirculated back to the heat exchangers.
This Fukushima design looks like it is combining radioactive steam and feed water.
Seems odd.
excellent video concise and to the point
Very good and thorough explanation.
Explanations you probably shouldn't accept: "There was very little spent fuel in the chamber."
I read somewhere about reactor designs that are passively (don't remember the exact term) safe - meaning that if all safety systems fail, they will still not be a threat to the environment. I'm guessing these reactors are an older design?
Moral of the story... if you are going to build nuclear power plants along the coast of Japan, do more to protect the backup power generators. In other words, prepare for the worst case scenerio (which the engineers obviously didn't do).
All those people working in that disaster, where are they now. This is so sad. It will take decades to clean this up. Wow.
Why the hell would anyone build a nuclear reactor in a high earthquake zone?
This video helped more to explain why the meltdown took place , thank you.
We live in a world of "Lowest Bid wins the contract" - You get what you paid for.
Technical excellence - determined by an independent authority (Not a simple regulatory minimum) should be the only criteria for contract awards were failure means large scale destruction of life/environment.
A movie should be made about the heroism shown by these workers. God Bless.
Going to be more careful typing in "Cat vs. Skunk fight"
@12:13, you see bubbles in the Reactor Pool, why are they there? The video doesnt give a date though.
EDIT: Saw the film date at the end, Feb 2012. So I guess cooling maybe?
Great video. you explained everything well and the animations were great.