Understanding the accident of Fukushima Daiichi 

Yes

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.

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.

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.

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.

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.

No one asked me

😂

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?

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 RU-vid.. 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.

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!

None have died from radiation exposure.

​@@dav4x487unfortunately that's not true. One died of lung cancer in 2018 from his exposure. Very sad

well the thing is that japans entire coast line dropped 4 ft during the earthquake. lots of seawalls were rendered useless as a result.

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.

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*

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.

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.

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.

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?

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.

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.

Cadmium is even good neutron suppressor.

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

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?

Muito bom mesmo. Severino.

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.

A submarine diesel is no different to the diesels they used, neither will work when literally flooded.

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 ....

Only with a Dyson Swarm but humanity waste most of its time with short term political issues than with big advances.