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Fukushima Nuclear Accident – a simple and accurate explanation

Twitter updates: @BraveNewClimate

New 15 March: Fukushima Nuclear Accident – 15 March summary of situation

New 14 March: Updates and additional Q&A information here and Technical details here

福島原発事故-簡潔で正確な解説 (version 3)：(東京大学エンジニアリング在学生の翻訳) (thanks to Shota Yamanaka for translation)

Other translations: Italian, Spanish, German, 普通话

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Along with reliable sources such as the IAEA and WNN updates, there is an incredible amount of misinformation and hyperbole flying around the internet and media right now about the Fukushima nuclear reactor situation. In the BNC post Discussion Thread – Japanese nuclear reactors and the 11 March 2011 earthquake (and in the many comments that attend the top post), a lot of technical detail  is provided, as well as regular updates. But what about a layman’s summary? How do most people get a grasp on what is happening, why, and what the consequences will be?

Below I reproduce a summary on the situation prepared by Dr Josef Oehmen, a research scientist at MIT, in Boston. He is a PhD Scientist, whose father has extensive experience in Germany’s nuclear industry. This was first posted by Jason Morgan earlier this evening, and he has kindly allowed me to reproduce it here. I think it is very important that this information be widely understood.

Please also take the time to read this: An informed public is key to acceptance of nuclear energy — it was never more relevant than now.

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NOTE: Content Updated 15 March, see: http://mitnse.com/

We will have to cover some fundamentals, before we get into what is going on.

Construction of the Fukushima nuclear power plants

The plants at Fukushima are Boiling Water Reactors (BWR for short). A BWR produces electricity by boiling water, and spinning a a turbine with that steam. The nuclear fuel heats water, the water boils and creates steam, the steam then drives turbines that create the electricity, and the steam is then cooled and condensed back to water, and the water returns to be heated by the nuclear fuel. The reactor operates at about 285 °C.

The nuclear fuel is uranium oxide. Uranium oxide is a ceramic with a very high melting point of about 2800 °C. The fuel is manufactured in pellets (cylinders that are about 1 cm tall and 1 com in diameter). These pellets are then put into a long tube made of Zircaloy (an alloy of zirconium) with a failure temperature of 1200 °C (caused by the auto-catalytic oxidation of water), and sealed tight. This tube is called a fuel rod. These fuel rods are then put together to form assemblies, of which several hundred make up the reactor core.

The solid fuel pellet (a ceramic oxide matrix) is the first barrier that retains many of the radioactive fission products produced by the fission process.  The Zircaloy casing is the second barrier to release that separates the radioactive fuel from the rest of the reactor.

The core is then placed in the pressure vessel. The pressure vessel is a thick steel vessel that operates at a pressure of about 7 MPa (~1000 psi), and is designed to withstand the high pressures that may occur during an accident. The pressure vessel is the third barrier to radioactive material release.

The entire primary loop of the nuclear reactor – the pressure vessel, pipes, and pumps that contain the coolant (water) – are housed in the containment structure.  This structure is the fourth barrier to radioactive material release. The containment structure is a hermetically (air tight) sealed, very thick structure made of steel and concrete. This structure is designed, built and tested for one single purpose: To contain, indefinitely, a complete core meltdown. To aid in this purpose, a large, thick concrete structure is poured around the containment structure and is referred to as the secondary containment.

Both the main containment structure and the secondary containment structure are housed in the reactor building. The reactor building is an outer shell that is supposed to keep the weather out, but nothing in. (this is the part that was damaged in the explosions, but more to that later).

Fundamentals of nuclear reactions

The uranium fuel generates heat by neutron-induced nuclear fission. Uranium atoms are split into lighter atoms (aka fission products). This process generates heat and more neutrons (one of the particles that forms an atom). When one of these neutrons hits another uranium atom, that atom can split, generating more neutrons and so on. That is called the nuclear chain reaction. During normal, full-power operation, the neutron population in a core is stable (remains the same) and the reactor is in a critical state.

It is worth mentioning at this point that the nuclear fuel in a reactor can never cause a nuclear explosion like a nuclear bomb. At Chernobyl, the explosion was caused by excessive pressure buildup, hydrogen explosion and rupture of all structures, propelling molten core material into the environment.  Note that Chernobyl did not have a containment structure as a barrier to the environment. Why that did not and will not happen in Japan, is discussed further below.

In order to control the nuclear chain reaction, the reactor operators use control rods. The control rods are made of boron which absorbs neutrons.  During normal operation in a BWR, the control rods are used to maintain the chain reaction at a critical state. The control rods are also used to shut the reactor down from 100% power to about 7% power (residual or decay heat).

The residual heat is caused from the radioactive decay of fission products.  Radioactive decay is the process by which the fission products  stabilize themselves by emitting energy in the form of small particles (alpha, beta, gamma, neutron, etc.).  There is a multitude of fission products that are produced in a reactor, including cesium and iodine.  This residual heat decreases over time after the reactor is shutdown, and must be removed by cooling systems to prevent the fuel rod from overheating and failing as a barrier to radioactive release. Maintaining enough cooling to remove the decay heat in the reactor is the main challenge in the affected reactors in Japan right now.

It is important to note that many of these fission products decay (produce heat) extremely quickly, and become harmless by the time you spell “R-A-D-I-O-N-U-C-L-I-D-E.”  Others decay more slowly, like some cesium, iodine, strontium, and argon.

What happened at Fukushima (as of March 12, 2011)

The following is a summary of the main facts. The earthquake that hit Japan was several times more powerful than the worst earthquake the nuclear power plant was built for (the Richter scale works logarithmically; for example the difference between an 8.2 and the 8.9 that happened is 5 times, not 0.7).

When the earthquake hit, the nuclear reactors all automatically shutdown. Within seconds after the earthquake started, the control rods had been inserted into the core and the nuclear chain reaction stopped. At this point, the cooling system has to carry away the residual heat, about 7% of the full power heat load under normal operating conditions.

The earthquake destroyed the external power supply of the nuclear reactor. This is a challenging accident for a nuclear power plant, and is referred to as a “loss of offsite power.” The reactor and its backup systems are designed to handle this type of accident by including backup power systems to keep the coolant pumps working. Furthermore, since the power plant had been shut down, it cannot produce any electricity by itself.

For the first hour, the first set of multiple emergency diesel power generators started and provided the electricity that was needed. However, when the tsunami arrived (a very rare and larger than anticipated tsunami) it flooded the diesel generators, causing them to fail.

One of the fundamental tenets of nuclear power plant design is “Defense in Depth.” This approach leads engineers to design a plant that can withstand severe catastrophes, even when several systems fail. A large tsunami that disables all the diesel generators at once is such a scenario, but the tsunami of March 11th was beyond all expectations. To mitigate such an event, engineers designed an extra line of defense by putting everything into the containment structure (see above), that is designed to contain everything inside the structure.

When the diesel generators failed after the tsunami, the reactor operators switched to emergency battery power. The batteries were designed as one of the backup systems to provide power for cooling the core for 8 hours. And they did.

After 8 hours, the batteries ran out, and the residual heat could not be carried away any more.  At this point the plant operators begin to follow emergency procedures that are in place for a “loss of cooling event.” These are procedural steps following the “Depth in Defense” approach. All of this, however shocking it seems to us, is part of the day-to-day training you go through as an operator.

At this time people started talking about the possibility of core meltdown, because if cooling cannot be restored, the core will eventually melt (after several days), and will likely be contained in the containment. Note that the term “meltdown” has a vague definition. “Fuel failure” is a better term to describe the failure of the fuel rod barrier (Zircaloy).  This will occur before the fuel melts, and results from mechanical, chemical, or thermal failures (too much pressure, too much oxidation, or too hot).

However, melting was a long ways from happening and at this time, the primary goal was to manage the core while it was heating up, while ensuring that the fuel cladding remain intact and operational for as long as possible.

Because cooling the core is a priority, the reactor has a number of independent and diverse cooling systems (the reactor water cleanup system, the decay heat removal, the reactor core isolating cooling, the standby liquid cooling system, and others that make up the emergency core cooling system). Which one(s) failed when or did not fail is not clear at this point in time.

Since the operators lost most of their cooling capabilities due to the loss of power, they had to use whatever cooling system capacity they had to get rid of as much heat as possible. But as long as the heat production exceeds the heat removal capacity, the pressure starts increasing as more water boils into steam. The priority now is to maintain the integrity of the fuel rods by keeping the temperature below 1200°C, as well as keeping the pressure at a manageable level. In order to maintain the pressure of the system at a manageable level, steam (and other gases present in the reactor) have to be released from time to time. This process is important during an accident so the pressure does not exceed what the components can handle, so the reactor pressure vessel and the containment structure are designed with several pressure relief valves. So to protect the integrity of the vessel and containment, the operators started venting steam from time to time to control the pressure.

As mentioned previously, steam and other gases are vented.  Some of these gases are radioactive fission products, but they exist in small quantities. Therefore, when the operators started venting the system, some radioactive gases were released to the environment in a controlled manner (ie in small quantities through filters and scrubbers). While some of these gases are radioactive, they did not pose a significant risk to public safety to even the workers on site. This procedure is justified as its consequences are very low, especially when compared to the potential consequences of not venting and risking the containment structures’ integrity.

During this time, mobile generators were transported to the site and some power was restored.  However, more water was boiling off and being vented than was being added to the reactor, thus decreasing the cooling ability of the remaining cooling systems. At some stage during this venting process, the water level may have dropped below the top of the fuel rods.  Regardless, the temperature of some of the fuel rod cladding exceeded 1200 °C, initiating a reaction between the Zircaloy and water. This oxidizing reaction produces hydrogen gas, which mixes with the gas-steam mixture being vented.  This is a known and anticipated process, but the amount of hydrogen gas produced was unknown because the operators didn’t know the exact temperature of the fuel rods or the water level. Since hydrogen gas is extremely combustible, when enough hydrogen gas is mixed with air, it reacts with oxygen. If there is enough hydrogen gas, it will react rapidly, producing an explosion. At some point during the venting process enough hydrogen gas built up inside the containment (there is no air in the containment), so when it was vented to the air an explosion occurred. The explosion took place outside of the containment, but inside and around the reactor building (which has no safety function).  Note that a subsequent and similar explosion occurred at the Unit 3 reactor. This explosion destroyed the top and some of the sides of the reactor building, but did not damage the containment structure or the pressure vessel. While this was not an anticipated event, it happened outside the containment and did not pose a risk to the plant’s safety structures.

Since some of the fuel rod cladding exceeded 1200 °C, some fuel damage occurred. The nuclear material itself was still intact, but the surrounding Zircaloy shell had started failing. At this time, some of the radioactive fission products (cesium, iodine, etc.) started to mix with the water and steam. It was reported that a small amount of cesium and iodine was measured in the steam that was released into the atmosphere.

Since the reactor’s cooling capability was limited, and the water inventory in the reactor was decreasing, engineers decided to inject sea water (mixed with boric acid – a neutron absorber) to ensure the rods remain covered with water.  Although the reactor had been shut down, boric acid is added as a conservative measure to ensure the reactor stays shut down.  Boric acid is also capable of trapping some of the remaining iodine in the water so that it cannot escape, however this trapping is not the primary function of the boric acid.

The water used in the cooling system is purified, demineralized water. The reason to use pure water is to limit the corrosion potential of the coolant water during normal operation. Injecting seawater will require more cleanup after the event, but provided cooling at the time.

This process decreased the temperature of the fuel rods to a non-damaging level. Because the reactor had been shut down a long time ago, the decay heat had decreased to a significantly lower level, so the pressure in the plant stabilized, and venting was no longer required.

***UPDATE – 3/14 8:15 pm EST***

Units 1 and 3 are currently in a stable condition according to TEPCO press releases, but the extent of the fuel damage is unknown.  That said, radiation levels at the Fukushima plant have fallen to 231 micro sieverts (23.1 millirem) as of 2:30 pm March 14th (local time).

***UPDATE – 3/14 10:55 pm EST***

The details about what happened at the Unit 2 reactor are still being determined.  The post on what is happening at the Unit 2 reactor contains more up-to-date information.  Radiation levels have increased, but to what level remains unknown.

By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

874 replies on “Fukushima Nuclear Accident – a simple and accurate explanation”

@Bill Bradshaw on 26 March 2011 at 1:57:

As can be concluded by examining , a fast breeder requires only 2 or 3 Megagrams of uranium per year for each gigawatt of generation. Roughly twice that amount of uranium will pass through the plant’s condenser each year, dissolved in seawater. This brings ocean extraction well into the feasible range, in contrast to your quoted passage from Finrod’s blog. And so, inexhaustible fuel is real — using fast breeders.

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This brings ocean extraction well into the feasible range, in contrast to your quoted passage from Finrod’s blog. And so, inexhaustible fuel is real — using fast breeders.

That particular comment in my blog related to the fueling of light water reactors. I agree that breeders are necessary for the truly sustainable nuclear power systems of the future, but they might well be thermal breeders using the Th-232 to U-233 cycle rather than (or as well as) fast breeders.

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“Radiation levels are skyrocketing around Japan’s Fukushima nuclear plant as reports indicate that a radioactive core has overheated and melted through its containment vessel and onto a concrete floor. Radiation levels inside reactor two were recently gauged at 1,000 millisieverts per hour — a level so high that workers could only remain in the area for 15 minutes under current exposure guideline.”

http://www.guardian.co.uk/world/2011/mar/29/japan-lost-race-save-nuclear-reactor

I don’t have a problem with nuclear power. I have a problem with those that run the industry. My solution… those that profit in the nuclear industry should be the ones who live within a 70 mile radius of the nuclear plants and be the ones who do the cleanup in case of an accident. Build a plant in their neighborhood.

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I live in Tokyo and it crossed my mind that there were tremendous releases of radioactivity from South Pacific and Asian hydrogen bomb tests from around 1950 to the first nuclear test ban agreements in the ’60s (I believe). In those days, such horrific tests were more or less taken for granted by most people. I wonder what are the qualitative and quantitative differences between those repeated tests by the U.S., France, Britain, China and the U.S.S.R. and what is happening or might happen at Fukushima, in terms of effects on the oceans and the atmosphere. Did those tests, singly or cumulatively, dwarf the current disaster, or were they essentially different in their effects? And what is the difference between a (Chinese) H-bomb test on land and, say, Chernobyl?

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This seems a lucent and cogent explanation, but events seem to have run beyond the explanation here. Plutonium found in the environment and extra-ordinary levels of radioactive seawater would seem to me to indicate a breech of the reactor core, no?

Fukashima won’t ‘blow up’, the cores are in shut down, and the configuration of the materials wouldn’t allow that fast a chain reaction anyway (although it seems a lot of can’t-happens in fact did happen in this case). Chernobyl was a case of the graphite core burning and these radioactive by products being released which fallout from nuclear or hydrogen bombs has a much different constituency.

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Hi,

I just like to know if the Fukushima containments
were nitrogen filled at the time of the accident.
Nitrogen filling is standard in German BWRs.
This prevents a hydrogen explosion.

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Something that has not been covered so far (or rather I can find no comment on the event):

Fukushima 1 containment building exploded early on with a clean looking explosion and a blue flash. It makes sense that hydrogen and oxygen had built up inside and exploded blowing off the building’s outer shell.

Reactor 3 a few days later suffered a much more serious vertical explosion containing much debris and large lumps of falling material. What was actually thrown up? Is it possible that this was concrete containment material blown off by hydrogen trapped deeper in the plant?

If this was the case it is really no surprise that fissile materials were found outside the plant. And the spent fuel storage pool must surely have been damaged.

Judging by the ferocity of that explosion, the recently found 20cm crack is probably the tip of a very large iceberg of cracks.

Does anyone have any information on this?

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[deleted – breaks the “Citing literature” BNC rule:]
Citing literature and other sources — appropriate and interesting citations and links within comments are welcomed, but please DO NOT cite material that you have not yourself read, digested and understood. As a general rule, please introduce any and every link or reference with a short description of the material, your judgement on its quality, and the specific reason you are including it (i.e. how it is relevant to the discussion).

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I have read and digested, and understood this picture of the trench near one of he reactors that is leaking some radioactivity into the sea. The picture was supplied by Tepco so I am assuming it is good quality material.

I also think it is very relevant to the entire incident since this seems to be where the majority of the material leaking into the sea is coming from.

Does the radiation level of 1000mSv/hr 1.2m above the water indicate volatile substances (like iodine) in the water are escaping or that much hgher levels would be found at the waters surface?

It does not address the issue of where the water in the trench comes from and I was hoping for some confirmation from the experts on this site that it could not have come from inside any of the containment vessels.

Click to access 110402e1.pdf

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can you speak in my language please
not like ‘the miniscule boat crashed ferociously on the rocks’ but ‘big wind made small boat crash’

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“””””A commentator on NHK World has said that TEPCO did not take the initiative to use sea-water cooling at Fukushima because of the damage it could do to any future plant operation and only did so when instructed to by the Ministry and the Government.”””””

http://ktwop.wordpress.com/2011/03/16/tepco-delayed-using-sea-water-for-cooling-until-instructed-to/

Question to BWR ‘experts’…could the fuel failures & hydrogen explosions have been prevented had they added sea water earlier????

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I’m not a nuclear expert but do have a background in coal fired power plants. I am certain that sea water would have done the job if it had been used earlier, but the plant had no power. The generators were wrecked and the batteries went flat. Fire pumps were hooked up but they would struggle to give enough pressure and that’s probably why they failed and then the water levels dropped. etc. etc.
I suspect the management systems failed to react and pull in outside resources because no-one expected to lose all the back up systems at the same time. If it was run like the plant I used to work in, the operations level engineers were always “responsible for” but when they needed to get things done urgently they had no authority with some quite small decisions always being pushed up the management hierarchy. They would have needed board level meeting to discuss portable generators.

However, building the plant with all the back up equipment facing the sea had to be the biggest mistake. Why it was never placed higher up behind we can only guess. I suspect it was just cheaper and easier and the American designers never even thought about the Tsumami risk.

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Question. 4 u smart people. Should the station blackout protocol provide an avenue to restart a scrammed reactor if you cross a threshold for power availability? It just occurred to me today that all the damage we’re seeing is a result of loss of power. It’s ironic because the reactor was scrammed as a safety measure yet that’s the one measure that set off this entire chain of events. If they had restarted one of the reactors before the battery power ran out, would that have allowed power to run all the systems?

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Bob Cov, on 6 April 2011 at 10:53 AM — I can’t answer your question with any authority. For the situation at Fukushima Dai-ichi the answer is irrelevant as the tsunami removed all possiblity of station supplied power. Indeed, the workers are still removing water so that eventually the station pumps (or replacements) can be used.

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[Comment deleted. Violation of the citation policy]
MODERATOR
It seems I have to keep repeating this but a throw away line with a link supplied is not good enough.Please re-submit with more comment – see rule below.

BARRY BROOK The commenting rules are not meant to be confusing, they’re meant to be logical. This is not a forum for cut-and-pasting slabs of text, with no other comment other than a link. Tell people why you think they should be interesting in reading this, and what it means for this discussion. Otherwise, you’re not thinking and not contributing. Simple as that.

Citing literature and other sources: appropriate and interesting citations and links within comments are welcomed, but please DO NOT cite material that you have not yourself read, digested and understood. As a general rule, please introduce any and every link or reference with a short description of the material, your judgement on its quality, and the specific reason you are including it (i.e. how it is relevant to the discussion).
Remember, we are moderating, but are not in the business of censoring criticism — we welcome well-presented critiques. The principal concern is working out how to conduct this debate in a civil and evidence-based manner, and do it well.

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Now that this an admitted catastrophic event>
What is the projected avenue of attack?
And what is in store for not only Japan but the World?

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Hilarious. Delete the truth away all you like but the fact is that I said, two things in the middle of this crisis that have both become true.

I said this was going to go on for months, if not years. I said this was a level 7 accident easy. Various people argued against these POV’s. That turned out to be wishful thinking.

I see that you used the opportunity to delete, not just my “throwaway comment” but the article with that contained the very important official information as well, which is that the Fukushima accident is a level 7 event: a catastrophe.

The pro-nuclear movement is doing no service to itself by constantly underestimating and downplaying the significance of this event. It makes it look really naive, at best, and even dishonest when the facts are revealed.

If you want people to trust you as a source, you had better work on this issue. Fukushima has been an huge PR disaster for you guys, and you are only making it worse with by constantly trying to paint one rosy picture after another, each one revealed to be false as new material is released.

A shame really, this started out as an interesting thread, with some great discussion about physics and debate. But now it seems to have become an exercise in media control.

The fact is that my more cautious approach, and realistic projections of the outcomes mean that I have maintained my credibility, while you have not.

If you want people to support nuclear power, which I do within certain limitations, because I have a fair bit of knowledge about the science, then you had better start doing a better job at making realistic projections and risk assessments.

Your personal moderators note is completely off-topic. Perhaps you are stressed out? Perhaps you have staked so much of your personal reputation on nuclear power that you are no longer able to make proper assessments about what is right before your very eyes? I don’t know. All I did was post a section of an article about how the Fukushima accident has now be reclassified as as a level 7 accident, sourced from the Canadian Broadcasting Corporation, a perfectly reputable source.

You chose to delete the hard evidence along with my off-hand told you so. That says everything. You can’t sweep this catastrophe under the rug just by deleting blog notes and news stories you don’t like.

I made no comment whatsoever that would reveal anything about my understanding of the situation except to say that I am “batting 100%”, which is true, because I said 2 weeks ago that this was a level 7 “catastrophic” nuclear event. Indeed, the fact that I pointed this out weeks ago, while you and others were clinging to the notion that it was no worse and than “TMI”.

I suggest to you that my 100% accurate observation, shows clearly that my reading and digestion of the material has been far better than your own. Indeed, the evidence is that it is you who has not “read, digested and understood” the relevant material on the catastrophic Fukushima Nuclear accident.

I wont be coming back. So good luck.
MODERATOR
You are being rather precious here.

The citation policy on BNC applies to all and this particular comment of yours violated the rule which states that it is not enough to simply say you are/were right and present a link to follow, but rather that you offer something to the debate based on what you have read and understood from the link. Your previous comments have been posted as/when they followed the comments policy. You have not been specially singled out as an example for the citation rule – comments from other posters which violate the rule have been dealt with in the same way. The policy is to delete the link and ask for a re-post with more detailed comments.

It is not your “right” to comment on BNC (which is a personal, private blog) and you, like everyone else, will be subject to the comments policy. If you don’t want to abide by that then please go elsewhere to an un-moderated blog or better still, start your own with all the hours of unpaid work that involves. There are plenty of open slather cesspits on the net to choose from.

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@ steviesmyths:

Fukushima has been an huge PR disaster for you guys, and you are only making it worse with by constantly trying to paint one rosy picture after another, each one revealed to be false as new material is released.

I went out to dinner with an anti-nuclear friend last night. Unbidden she told me she’s reserving judgement on the whole Fukushima matter until the press free-for-all has died down. Apparently she has started to consider nuclear power might actually be necessary after all, given the conversations we’ve had. Interestingly, she has not responded to Fukushima as a confirmation of her previous stand. My friend has decided to look carefully at the end result of the accident in a few months, and see if that result matches the current media coverage.

Let me be absolutely clear that this lady has been VERY anti-nuclear. I remember us having a conversation where she blurted out that radiation is evil, in an absolute statement on the intrinsic moral properties of radiation. That was two or three years ago. Now she’s reached a point of deep scepticism of the sensationalist media coverage, and is (reluctantly) leaning toward nuclear.

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“I went out to dinner with an anti-nuclear friend last night. Unbidden she told me she’s reserving judgement on the whole Fukushima matter until the press free-for-all has died down.”

Fantastic stuff. That’s what I like to hear.

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@ Bill Bradshaw:

[Previous comment by Bradshaw was deleted for playing the man not the ball]

I realise that you are just trolling, but I will point out that it was my friend who raised the issue. We met to discuss a completely seperate topic, and the bulk of the evening was taken up with that.

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Has this been mentioned elsewhere?
IAEA Briefing on Fukushima Nuclear Accident (13 April 2011, 14:30 UTC)
http://www.iaea.org/press/?p=2051#more-2051
…
MEXT reported on measurements of strontium-89 (half-life: 50.5 days) and strontium-90(half-life: 28.8 years) in three samples taken in one village in the Fukushima prefecture on 16 March. The activities in soil for Sr-89 ranged from 13 and 260 Bq/kg and for Sr-90 between 3.3 and 32 Bq/kg. Sr-90 was also distributed globally during nuclear weapons’ testing in the atmosphere, typical global levels of Sr-90 in surface soils are in the order of one to a few becquerel per kg. Strontium was also measured in plant samples in four others villages, with values ranging from 12 to 61 Bq/kg for Sr-89 and 1.8 to 5.9 Bq/kg for Sr-90….

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@FINROD
Calling me a troll is “playing the man not the ball”
AND it is incorrect. I quote from the Urban dictionary definition of troll here:
“A troll usually flames threads without staying on topic, unlike a “Flamer” who flames a thread because he/she disagrees with the content of the thread.”
I am posting here because I disagree with the contention that people are “fearing something that they don’t understand” with nuclear fission and with the contention that it can be made ‘safe’.

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■Minimum requirements for PM Kan’s survival – Can we entrust the Nuclear and the Reconstruction to him? –

A roadmap for stableness of Fukushima Daiichi nuclear power plant accident that takes max 9 months was announced by TEPCO on 17th at last.
Japanese prime minister Naoto Kan expressed his every effort in tackling it at the Diet on the next 18th.

On the same day, Chief Cabinet Secretary Edano mentioned to ask for senior officers of METI to refrain from being parachuted ”AMAKUDARI” into TEPCO for the time.

Kan regime’s dealing to the disaster looks like to have became better than ever bad operations.

However, Kan just said that “Government will cooperate for TEPCO’s work, get together, encourage it, do things as can in full power”.
The government still has been skillfully avoided taking responsibility in a supporter’s stance for the devastating accident.
So the Government’s initiative is completely missing.

Edano avoided to call a recent parachute “AMAKUDARI” in a parliamentary answer in February.

In addition, he demanded a vague “foreseeable future refrain from it”.
And I can’t feel his reflection on “AMAKUDARI” that made a hollowing of regulation led to a expansion of the nuclear accident.

It is hard to say that Kan administration has qualification and capability for dealing the nuclear accident and for doing recovery and reconstruction to the earthquake disaster.

At least the following conditions are necessary for Kan to continue sitting in the office in the future.

(1) Honestly apologize to the people and the international community about mistake and concealment of information for nuclear accidents.
(2) Making a government commitment to the roadmap for stableness of the nuclear accident.
(3) Making a real decision-making organization with all parties participation for disaster recovery and restoration, and obeying the decision.

Without fulfilling these conditions, the prime minister must resign immediately.

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I am interested in the contents of the spent fuel rod pools in all 4 reactors. Are they still being cooled? What will happen if they are not cooled? Without cooling, can they become critcal?

As to crane removal of the rod assemblies – I believe the rod cranes of 1, 3 and 4 (and their rails)are damaged beyond repair – the supporting structure is missing in some cases. So how will the hundred of tonnes of spent fuel rods be removed?

Finally, what is the capacity of water pond in the spent fuel rod containment building (to the left of #4)? What happens when it is full of highly radioactive sump water?

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Cek magdurlari, on 29 September 2011 at 9:54 AM — News articles from World Nuclear News will anser must of your questions. In general the reactors are being covered with a substantial protective cover which will be left in place for several years before decommisioning begins. The sump water is being treated in the undamaged radioactive waste removal facility.

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MEXT reported on measurements of strontium-89 (half-life: 50.5 days) and strontium-90(half-life: 28.8 years) in three samples taken in one village in the Fukushima prefecture on 16 March. The activities in soil for Sr-89 ranged from 13 and 260 Bq/kg and for Sr-90 between 3.3 and 32 Bq/kg. Sr-90 was also distributed globally during nuclear weapons’ testing in the atmosphere, typical global levels of Sr-90 in surface soils are in the order of one to a few becquerel per kg. Strontium was also measured in plant samples in four others villages, with values ranging from 12 to 61 Bq/kg for Sr-89 and 1.8 to 5.9 Bq/kg for Sr-90….

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(Comment deleted)
MODERATOR
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Great post. Public education on events such as this occurs far too often after the event has occurred. On ongoing program of education where there is risk to the public should be undertaken by agencies that provide oversight to these types of capabilities

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[…] One reason is that we feel natural disasters are…well natural. Things we can’t do anything about, whereas nuclear accidents are self-inflicted. Superficially, that is true but could we really do without energy? If all electricity production ceased even more people would die. Without getting into the debate about whether or not we could replace nuclear with other forms of energy generation, it seems that the feelings about these things are some how deep seatedly emotional and not rational. If you want a rational explanation of the Fukushima events there is a simple account here. […]

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　　In March 11th 2011, six nuclear reactors have been shutdown by 9.0 magnitude

Earthquake and tsunami causing the reactors to malfunction and releasing the toxic

nuclear waste to the outer environment. As time passed, the nuclear wastes spread more

and more, becoming the largest and one of the well known nuclear incident since

Chernobyl disaster in Ukraine, receiving scale of seven on the international nuclear event

scale.
　　Before the incident, the Fukushima Daiichi Nuclear Power Plant was one of the

fifteen largest nuclear power station in the world and also the first nuclear plant to be

designed and constructed with General Electric, Boise, and TEPCO, also known as

Tokyo electric power company. As one of the largest nuclear power plant, they have been

working under normal conditions until year 2010, where Unit 3’s fuel have been

converted from low enriched Uranium to six percent of plutonium containing mixed

oxide fuel resulting higher increase in chance of being in danger. One of the scientists

describe: “Plutonium may be the worst of all the fission byproducts that could enter the

environment as a result of the nuclear disaster” (Live science, 2011). While unit 3 was

given improvement in fuel for increase the amount of electricity produced, Some of the

other units have been scheduled for shutdown later 2011, however it was later granted for

10 more years of extended operation until the power plant units were later damaged by

the earthquake and tsunami. During the incident, all the units had emergency diesel

generators and DC batteries to keep the reactors cool even when the power plant

experienced power loss. Unfortunately these systems were believed to be vulnerable to

Flooding, which later became one of the major causes for the major nuclear waste leak.

So what actually happened during the incident and what caused it to happen?

　　The famous Nuclear waste contamination incident, also known as Fukushima Daiichi

nuclear incident all started with a earthquake with the magnitude of 9.0 and what

followed. During the time of incident, the power plants have been working successfully,

producing large amount of electricity till March 11th 2011, where earthquake with a high

magnitude occur causing massive construction damage and tsunami. To avoid a potential

catastrophic failure, the reactors have been cooled down through the cooling system.

However as tsunami occur the reactors received damage and shutdown. What made

matter worse was that the backup cooling system created was also broken down due to

tsunami. Reason for breaking down of reactor unit’s backup electricity supply and

cooling system was because the emergency generators were made to supply the units but

were not design to sustain pressures and damage caused by tsunami. As the cooling

system failed to cool down the reactor units, the units itself continued to heat up and soon

exploding, damaging other units and spreading toxic wastes to the surrounding.

　　Sea currents have been one of the major reasons for this large scale nuclear waste
contamination. When water is contacted with the plant’s fuel rods, it becomes highly
radioactive. These contaminated water have been stored in a makeshift, hastily built
storage tanks about 160 Olympic-sized swimming pools, with about 400 tons added to the
tank daily. ( Japan’s Fukushima crisis: How did we get to this point?, CNN, 2013). At the beginning, we have thought that the tsunami and earthquake have caused the
destruction and damage to the plant causing a massive leak. Local scientist describes:
“ This incident have introduced mostly Iodine-131, Cesium-137, and Cesium-134, but
also a sprinkling Tellurium, Uranium, and Strontium to the area surrounding the power
plant” (True facts about ocean radiation and the Fukushima Disaster, Wikipedia, 2014).
However it was later revealed that TEPCO have been already leaking these contaminated
water offshore more than a year. Leaking these contaminated water causes massive
damage to the environment, but what makes things worse is that Fukushima coast has
some of the world’s strongest current and these currents help the toxic wastes far into the
Pacific Ocean causing great dispersion of the radioactive elements (Fukushima Daiichi
nuclear disaster, Wikipedia, 2014). These contaminated water spreading through the
currents are hard to stop and takes at least decade to clean up. Plant workers also have
tried to decrease the amount of wastes spreading through the environment by taking
emergency measures such as building chemical underground walls. However hardly any
of these ideas have succeed in improvement of the situation and the contamination spread
more and more, with estimated radioactivity released ranged from 10-40% of that of
Chernobyl, which was about 10-12% (Chernobyl, Wikipedia, 2014).
　　Changing construction structure illegally was another reason why this incident have
happened. For the nuclear reactor units to work safely, they are attached with the cooling
system to stop the units from overheating. In 1966, TEPCO have changed the piping
layout for the emergency cooling system. The original plan was to separate the piping
system for two reactors in the isolation condenser from each other. However as they
construction went on, TEPCO have changed certain structures during construction
without any recordings (Fukushima Daiichi nuclear power plant, Wikipedia, 2014). At
the beginning there seemed to be no problem at all. However after the tsunami have
caused a major breakdown of the power plant, the isolation condenser should have taken
over the function of the cooling pumps by producing steam to cool down the reactor.
However these condensers were unable to serve their purpose, causing malfunction. If the
condition of the power plant units were to be daily checked, and recorded truthfully, we
could have minimized the problem.
　　In response to the situation, Japanese government were unable to cope with the
situation. They should have realized the gravity of the situation when the tsunami swept
through the area. However, Japanese government did not keep records of the key
meetings during crisis. The investigation committee on the accident at the power station
reports that Japan’s response was flawed by “Poor communication and delays in releasing
on dangerous radiation leaks at the facility”. (Response to the Fukushima Daiichi Nuclear
Incident, 2014). The magazine ‘Economist’ describes: “The operating company was
poorly regulated and did not know what was going on. The operators made mistakes. The
representatives of the safety inspectorate fled. Some of the equipment failed. The
establishment repeatedly played down the risks and suppressed information about the
movement of the radioactive plume, so some people were evacuated from more lightly to
more heavily contaminated places” (The Economists, 2013). Due to their lack of
communication and poor recording skills, large amount of time have been wasted to stop
the situation from being worsen. After the evacuation, no death have been followed short
term radiation exposure, while 15,884 died due to the earthquake and tsunami.
(Fukushima Daiichi nuclear disaster, 2011). Still the life expectancy of the survivors
dropped and showed higher risk of developing cancer such as Leukemia, solid cancer,
and thyroid cancer. On my point of view, the actions taken by the Japanese government
showed too many childish errors and I would have posed different solution for the
problem.
　　First, all the nuclear waste from the nuclear power plant can be recycle to generate
more electricity. Nuclear Waste can be categorized into three different types: low-level
waste, intermediate-level waste, and high-level waste. For some people, they may believe
low-level waste is slightly safe. Well, the answer is no. Nuclear particles never disappear.
They go through the process known as half life where nuclear particles split for long
periods of time. Even if these particle split, they still emit radiation which may be weaker,
but still harmful. Therefore, there are possibility of producing electricity. For Low-level
waste, it can be used from hospitals, laboratories, and industries. These wastes are not
harmful to handle, but the handler need to handle them with extreme care. However, for
others, they incinerate the nuclear waste. For Intermediate-level waste, they contain more
higher level of radioactivity and require a proper shielding to use them. They are mainly
comprised of chemical sludge and reactor components, and contaminated materials from
the reactors itself. These can be solidified in concrete for disposal, but if they were to
produce enough radiation, there is a chance that they can be used for fuel it self. Lastly,
for High-level wastes, they are 3% volume of all rad waste, but they can be reused as
fuels once again. They contain highly radioactive fission products and takes long period
of time to break down during half life. It is same as the fuel itself. Because it heats up just
like the original fuel, the high-level waste also require a cooling system. When the fuel is
reprocessed, the separated waste is vitrified by incorporating it into borosilicate glass
which is sealed inside stainless steel canisters and disposed deep underground (Waste
management: Overview, World Nuclear Association, 2012).
　　Second, nuclear wastes can be used to power spacecrafts. With it’s considerable size and the amount of energy it is required to boost the space craft up requires considerable
amount of fuel and this is where nuclear waste comes in. In Europe, the European Space
Agency is piloting a 1 million pound program to use civil plutonium for nuclear batteries
to power ships on deep space missions. (oil price.com, 2013). If we were to use our current nuclear wastes, there are possibility that we can send space crafts with lower fuel
costs and can clean up the wastes at the same time. In Sellafield waste facility, UK, there
are 100 tons of plutonium and nuclear batteries can be made from an isotope known as
americium-241 in these decaying plutonium (oil price.com 2013). Sooner or later we will be able to see a space in the open market for the nuclear wastes which can be used to fuel and create nuclear batteries. Although there are large number of wastes still there are and increasing, these new ways of use can improve the environment and decrease the amount of waste building up on our earth.
　　Being a nuclear disaster worse than the Chernobyl itself, Fukushima Daiichi Nuclear
disaster have caused large number of people lost their home, family, and their health,
resulting 136,000 people to be displaced and sick from their houses and towns due to the
disaster (Japan Times, 2014). Still the citizens did not give up. They believe that one day they will receive happiness from all these misfortunes. Hoping that they will one day be freed from this disaster once and for all, the citizens marched on for the sake of family
and survival and they continue until every last souls of the citizens are saved.

Like

In March 11th 2011, six nuclear reactors have been shutdown by 9.0 magnitude

Earthquake and tsunami causing the reactors to malfunction and releasing the toxic

nuclear waste to the outer environment. As time passed, the nuclear wastes spread more

and more, becoming the largest and one of the well known nuclear incident since

Chernobyl disaster in Ukraine, receiving scale of seven on the international nuclear event

scale.

Before the incident, the Fukushima Daiichi Nuclear Power Plant was one of the

fifteen largest nuclear power station in the world and also the first nuclear plant to be

designed and constructed with General Electric, Boise, and TEPCO, also known as

Tokyo electric power company. As one of the largest nuclear power plant, they have been

working under normal conditions until year 2010, where Unit 3’s fuel have been

converted from low enriched Uranium to six percent of plutonium containing mixed

oxide fuel resulting higher increase in chance of being in danger. One of the scientists

describe: “Plutonium may be the worst of all the fission byproducts that could enter the

environment as a result of the nuclear disaster” (Live science, 2011). While unit 3 was

given improvement in fuel for increase the amount of electricity produced, Some of the

other units have been scheduled for shutdown later 2011, however it was later granted for

10 more years of extended operation until the power plant units were later damaged by

the earthquake and tsunami. During the incident, all the units had emergency diesel

generators and DC batteries to keep the reactors cool even when the power plant

experienced power loss. Unfortunately these systems were believed to be vulnerable to

Flooding, which later became one of the major causes for the major nuclear waste leak.

So what actually happened during the incident and what caused it to happen?

The famous Nuclear waste contamination incident, also known as Fukushima Daiichi

nuclear incident all started with a earthquake with the magnitude of 9.0 and what

followed. During the time of incident, the power plants have been working successfully,

producing large amount of electricity till March 11th 2011, where earthquake with a high

magnitude occur causing massive construction damage and tsunami. To avoid a potential

catastrophic failure, the reactors have been cooled down through the cooling system.

However as tsunami occur the reactors received damage and shutdown. What made

matter worse was that the backup cooling system created was also broken down due to

tsunami. Reason for breaking down of reactor unit’s backup electricity supply and

cooling system was because the emergency generators were made to supply the units but

were not design to sustain pressures and damage caused by tsunami. As the cooling

system failed to cool down the reactor units, the units itself continued to heat up and soon

exploding, damaging other units and spreading toxic wastes to the surrounding.

Sea currents have been one of the major reasons for this large scale nuclear waste

contamination. When water is contacted with the plant’s fuel rods, it becomes highly

radioactive. These contaminated water have been stored in a makeshift, hastily built

storage tanks about 160 Olympic-sized swimming pools, with about 400 tons added to the

tank daily. ( Japan’s Fukushima crisis: How did we get to this point?, CNN, 2013). At the beginning, we have thought that the tsunami and earthquake have caused the

destruction and damage to the plant causing a massive leak. Local scientist describes:

“ This incident have introduced mostly Iodine-131, Cesium-137, and Cesium-134, but

also a sprinkling Tellurium, Uranium, and Strontium to the area surrounding the power

plant” (True facts about ocean radiation and the Fukushima Disaster, Wikipedia, 2014).

However it was later revealed that TEPCO have been already leaking these contaminated

water offshore more than a year. Leaking these contaminated water causes massive

damage to the environment, but what makes things worse is that Fukushima coast has

some of the world’s strongest current and these currents help the toxic wastes far into the

Pacific Ocean causing great dispersion of the radioactive elements (Fukushima Daiichi

nuclear disaster, Wikipedia, 2014). These contaminated water spreading through the

currents are hard to stop and takes at least decade to clean up. Plant workers also have

tried to decrease the amount of wastes spreading through the environment by taking

emergency measures such as building chemical underground walls. However hardly any

of these ideas have succeed in improvement of the situation and the contamination spread

more and more, with estimated radioactivity released ranged from 10-40% of that of

Chernobyl, which was about 10-12% (Chernobyl, Wikipedia, 2014).

Changing construction structure illegally was another reason why this incident have

happened. For the nuclear reactor units to work safely, they are attached with the cooling

system to stop the units from overheating. In 1966, TEPCO have changed the piping

layout for the emergency cooling system. The original plan was to separate the piping

system for two reactors in the isolation condenser from each other. However as they

construction went on, TEPCO have changed certain structures during construction

without any recordings (Fukushima Daiichi nuclear power plant, Wikipedia, 2014). At

the beginning there seemed to be no problem at all. However after the tsunami have

caused a major breakdown of the power plant, the isolation condenser should have taken

over the function of the cooling pumps by producing steam to cool down the reactor.

However these condensers were unable to serve their purpose, causing malfunction. If the

condition of the power plant units were to be daily checked, and recorded truthfully, we

could have minimized the problem.

In response to the situation, Japanese government were unable to cope with the

situation. They should have realized the gravity of the situation when the tsunami swept

through the area. However, Japanese government did not keep records of the key

meetings during crisis. The investigation committee on the accident at the power station

reports that Japan’s response was flawed by “Poor communication and delays in releasing

on dangerous radiation leaks at the facility”. (Response to the Fukushima Daiichi Nuclear

Incident, 2014). The magazine ‘Economist’ describes: “The operating company was

poorly regulated and did not know what was going on. The operators made mistakes. The

representatives of the safety inspectorate fled. Some of the equipment failed. The

establishment repeatedly played down the risks and suppressed information about the

movement of the radioactive plume, so some people were evacuated from more lightly to

more heavily contaminated places” (The Economists, 2013). Due to their lack of

communication and poor recording skills, large amount of time have been wasted to stop

the situation from being worsen. After the evacuation, no death have been followed short

term radiation exposure, while 15,884 died due to the earthquake and tsunami.

(Fukushima Daiichi nuclear disaster, 2011). Still the life expectancy of the survivors

dropped and showed higher risk of developing cancer such as Leukemia, solid cancer,

and thyroid cancer. On my point of view, the actions taken by the Japanese government

showed too many childish errors and I would have posed different solution for the

problem.

First, all the nuclear waste from the nuclear power plant can be recycle to generate

more electricity. Nuclear Waste can be categorized into three different types: low-level

waste, intermediate-level waste, and high-level waste. For some people, they may believe

low-level waste is slightly safe. Well, the answer is no. Nuclear particles never disappear.

They go through the process known as half life where nuclear particles split for long

periods of time. Even if these particle split, they still emit radiation which may be weaker,

but still harmful. Therefore, there are possibility of producing electricity. For Low-level

waste, it can be used from hospitals, laboratories, and industries. These wastes are not

harmful to handle, but the handler need to handle them with extreme care. However, for

others, they incinerate the nuclear waste. For Intermediate-level waste, they contain more

higher level of radioactivity and require a proper shielding to use them. They are mainly

comprised of chemical sludge and reactor components, and contaminated materials from

the reactors itself. These can be solidified in concrete for disposal, but if they were to

produce enough radiation, there is a chance that they can be used for fuel it self. Lastly,

for High-level wastes, they are 3% volume of all rad waste, but they can be reused as

fuels once again. They contain highly radioactive fission products and takes long period

of time to break down during half life. It is same as the fuel itself. Because it heats up just

like the original fuel, the high-level waste also require a cooling system. When the fuel is

reprocessed, the separated waste is vitrified by incorporating it into borosilicate glass

which is sealed inside stainless steel canisters and disposed deep underground (Waste

management: Overview, World Nuclear Association, 2012).

Second, nuclear wastes can be used to power spacecrafts. With it’s considerable size and the amount of energy it is required to boost the space craft up requires considerable

amount of fuel and this is where nuclear waste comes in. In Europe, the European Space

Agency is piloting a 1 million pound program to use civil plutonium for nuclear batteries

to power ships on deep space missions. (oil price.com, 2013). If we were to use our current nuclear wastes, there are possibility that we can send space crafts with lower fuel

costs and can clean up the wastes at the same time. In Sellafield waste facility, UK, there

are 100 tons of plutonium and nuclear batteries can be made from an isotope known as

americium-241 in these decaying plutonium (oil price.com 2013). Sooner or later we will be able to see a space in the open market for the nuclear wastes which can be used to fuel and create nuclear batteries. Although there are large number of wastes still there are and increasing, these new ways of use can improve the environment and decrease the amount of waste building up on our earth.

Being a nuclear disaster worse than the Chernobyl itself, Fukushima Daiichi Nuclear

disaster have caused large number of people lost their home, family, and their health,

resulting 136,000 people to be displaced and sick from their houses and towns due to the

disaster (Japan Times, 2014). Still the citizens did not give up. They believe that one day they will receive happiness from all these misfortunes. Hoping that they will one day be freed from this disaster once and for all, the citizens marched on for the sake of family

and survival and they continue until every last souls of the citizens are saved.

                            Reference

Blog used: Fukushima Nuclear Accident – a simple and accurate explanation

Retrieved from:

Fukushima Nuclear Accident – a simple and accurate explanation

1) The Japan Times (2012). Fukushima’s appalling death toll

Retrieved from:

http://www.japantimes.co.jp/opinion/2014/03/01/editorials/fukushimas-appalling-death-toll/#.VGCRmHQtAqM

2) Deep Sea News (2013). True facts about Ocean Radiation and the Fukushima Disaster

Retrieved from:

http://deepseanews.com/2013/11/true-facts-about-ocean-radiation-and-the-fukushima-disaster/

3) CNN (2013). Japan’s Fukushima crisis: How did we get to this point?

Retrieved from:

http://www.cnn.com/2013/09/04/world/asia/japan-fukushima-nuclear-crisis-explainer/

4) Union of Concerned Scientists (2007). How it works: Water for Nuclear

Retrieved from:

http://www.ucsusa.org/clean_energy/our-energy-choices/energy-and-water-use/water-energy-electricity-nuclear.html#.VGA9GnQtAqM

5) Live Science (2011). Why is Plutonium more dangerous than Uranium?

Retrieved from:

http://www.livescience.com/33127-plutonium-more-dangerous-uranium.html

6) Wikipedia (2014). Fukushima Daiichi Nuclear Power Plant

Retrieved from:

http://en.wikipedia.org/wiki/Fukushima_Daiichi_Nuclear_Power_Plant

7) Wikipedia (2014). Fukushima disaster cleanup

Retrieved from:

http://en.wikipedia.org/wiki/Fukushima_disaster_cleanup

8) Wikipedia (2014). Chernobyl Disaster

Retrieved from:

http://en.wikipedia.org/wiki/Chernobyl_disaster

9) The Hiroshima syndrome (2014) Fukushima

Retrieved from:

http://www.hiroshimasyndrome.com/fukushima-accident-updates/fukushima-77-10-16-14.html

10) World Nuclear Association (2012) Waste Management: Overview

Retrieved from:

http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Nuclear-Wastes/Waste-Management-Overview/

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Has anything new been learned? I know the lessons are hard and unwelcome to the extent there’s “coulda shoulda didn’t” stuff coming out, and I know there’s still much unknown. It’d be good to keep focusing on this.

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