Talk:Fukushima nuclear accident

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fuel after the core meltdown was estimated to stop at approx. 0.7 m (2 ft 4 in) in depth, while the thickness of the containment floor is 7.6 m (25 ft). Gas sampling carried out before the report detected no signs of an ongoing reaction of the fuel with the concrete of the PCV and all the fuel in Unit 1 was estimated to be "well cooled down, including the fuel dropped on the bottom of the reactor". Fuel in Units 2 and 3 had melted, however less than in Unit 1. The report further suggested that "there is a range in the evaluation results" from "all fuel in the RPV (no fuel fallen to the PCV)" in Unit 2 and Unit 3, to "most fuel in the RPV (some fuel in PCV)". For Unit 2 and Unit 3, it was estimated that the "fuel is cooled sufficiently". According to the report, the greater damage in Unit 1 (when compared to the other two units) was due to the longer time that no cooling water was injected in Unit 1. This resulted in much more decay heat accumulating, as for about 1 day there was no water injection for Unit 1, while Unit 2 and Unit 3 had only a quarter of a day without water injection.

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is biased, scientifically speaking his point stands because it is more likely the man developed cancer due to secondhand smoke and that ionizing radiation from Nuclear accidents doesn't have a strong correlation with the type of Lung Cancer he developed (it's also overlooked that he exceeded his dose earlier in his career as well if one does want to attribute it to radiation, so it may be a non-Fukushima radiation-related death). The same can be said of the Thyroid cancer patients; I just updated the radiation related illnesses section with some recent studies including one that suggests in the interest of unbiased and neutral language that the UN and Japanese Government may be causing underreporting of Thyroid cancers (I couldn't find a 2024 follow up on this so there seems to not be any new information yet), but the overall scientific consensus remains that there is no evidence of a dose-response relationship due to ionizing radiation, and that the cancers are likely being detected via the screening effect.

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imperfections in the RPV, but in a situation in which the RCIC is used, this gas flows through the RCIC system and into the suppression pool, where some of the vaporized or suspended fission products are condensed or captured (scrubbed) by the SC, although some remainder (notably, radioactive noble gasses) will remain vaporized or suspended inside of the PCV. From the PCV, similar to the RPV, some small quantity inevitably leaks through small imperfections in the structure, but the predominant designed path for the escape of suspended radionuclides is through venting of the PCV where they are dispersed by the vent stack. However, if the PCV is compromised, the gas will be released directly into the secondary containment, and the potential loss of the SC function would also increase the concentration of unwanted fission products in the gas.

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determine how far the fuel had eroded and diffused into the concrete, it was estimated that the fuel remained within the PCV. In November 2013, Mari Yamaguchi reported for Associated Press that there are computer simulations that suggest that "the melted fuel in Unit 1, whose core damage was the most extensive, has breached the bottom of the primary containment vessel and even partially eaten into its concrete foundation, coming within about 30 cm (1 ft) of leaking into the ground" – a Kyoto University nuclear engineer said with regard to these estimates: "We just can't be sure until we actually see the inside of the reactors."

3769:"Within the first three days of the accident the entire core content of reactor 3 had melted through the RPV and fallen to the bottom of the PCV." This claim as it is currently written almost certainly cannot be verified or is at least contestable. First of all, the source is highly technical and relies on simulations which even the source expresses doubt in and on remote neutron measurement. Remote neutron measurement is not an established way of assessing PCV breaches and this source is clearly academic and speculative. Second, 4179:

event of accidents in the reactor or spent fuel pools”. This brief has led to ongoing research and development of Accident Tolerant Fuels, which are specifically designed to withstand the loss of cooling for an extended period, increase time to failure, and increase fuel efficiency. This is accomplished by incorporating specially designed additives to standard fuel pellets and replacing or altering the fuel cladding in order to reduce corrosion, decrease wear, and reduce hydrogen generation during accident conditions."

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its own category. I did look at the two U.S. shuttle disasters and was surprised neither had an investigation section. It would be worth looking at some of the other disasters like the recent collision of the ship destroying bridge in Baltimore or the ship that grounded and blocked the Suez Canal--to see how those articles placed the investigation section. --

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I agree that an entire paragraph about accident tolerant fuel research is too much for this article. Besides, it is written from the point of view of a single country. The paragraph could be deleted, or it could be shortened to a single sentence. For example: "After the accident, a lot of funding was

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The predominant mechanism by which fission products can leave the core during core melt is through vaporization, thus only relatively volatile nuclides mix with the vaporized coolant and can be transported by the flow of gas. This gas can then exit the RPV and into the PCV through small leak paths in

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Once released into the atmosphere, those which remain in a gaseous phase will simply be diluted by the atmosphere, but some which precipitate will eventually settle on land or in the ocean. Thus, the majority (90~99%) of the radionuclides which are deposited are isotopes of iodine and caesium, with a

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In February 2017, six years after the accident, radiation levels inside the Unit 2 containment building were crudely estimated to be about 650 Sv/h. The estimation was revised later to 80 Sv/h. These readings were the highest recorded since the accident occurred in 2011 and the first recorded in that

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Lawsuits and Legal Settlements are problematic because they can't be scientifically proven to be tied to the radiation exposure. Radiation Scientist James Conca pointed this out in a 2018 Forbes article that the man who developed Cancer likely did not receive it from Fukushima, and while his article

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This is an odd source. It is a personal website publishing the author's POV. These claims are are not presented as POV in the article. Given that it is the only source for "The oldest operating nuclear power station in the world, Beznau, which has been operating since 1969, has a 'Notstand' hardened

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I wanted to open some discussion as to whether the this section is notable: "In the wake of the accident, the Senate Appropriations Committee requested the United States Department of Energy “to give priority to developing enhanced fuels and cladding for light water reactors to improve safety in the

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Here I wanted to point out that "The explosion was later found to be caused by hydrogen passing to unit 4 from unit 3 through shared pipes." is not a neutral representation of the source. The source clearly shows there was no consensus on the cause of the hydrogen gas and in that analysis the unit 3

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Subsequent analysis in November suggested that this extended period without cooling resulted in the melting of the fuel in unit 1, most of which would have escaped the reactor pressure vessel (RPV) and embedded itself into the concrete at the base of the PCV. Although at the time it was difficult to

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This sentence in the lead points references this source The source reports mental health effects but does not list them as a cause for death. In fact, it mostly attributes the deaths to pneumonia. Unless there is another source that says pneumonia can be caused by mental stress (which I doubt but I

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TEPCO released estimates of the state and location of the fuel in a November 2011 report. The report concluded that the Unit 1 RPV was damaged during the accident and that "significant amounts" of molten fuel had fallen into the bottom of the PCV. The erosion of the concrete of the PCV by the molten

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I second the spirit of this suggestion. However this could be controversial. Additionally, even if you have the right spirit I think it will be hard to get it right given that it is the lead to a complex topic. I encourage you to boldly attempt to make this revision. We shall see what others think.

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I looked into this source. It seems like a legit research project. However the editor that cited it on here did not say what article they were citing and only linked the homepage which changes regularly. I looked in wayback machine but it is pretty much impossible to determine what the original ref

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or at least needs additional sources to verify all the claims. Given the single source it is not clear to be that the claims are also notable. There is a lot of published research about the accident, but a single publication in a second-rate journal cannot be used as the standard for notability or

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I don't think the investigations should be under "Consequences"--which should focus on effects to living beings, the environment, structures, infastructure, etc. However, I don't think it should have been under "Criticisms" either. Investigations are supposed to be independent. I would put it in

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UPI is the only source I can find claiming "More than 30,000 people marched on 2 June 2013, in Tokyo against restarting nuclear power plants. Marchers had gathered more than 8 million petition signatures opposing nuclear power." I would think multiple source would report a petition with 8 million

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Maybe the better middle ground is to just state that there are various construction projects happening at Daiichi. Which will support the safe removal of all the fuel from the reactors and these projects are scheduled to be completed by 2031? I would appreciate some editors weighing in on this.

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myself and other users have mentioned. Those are mentioned (or at least should be mentioned) in the sections detailing the events of each unit. Furthermore, I do not think it is worthwhile to include those studies into these section as those studies a primarily part of the cleanup effort and are

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in the PCV. In March 2015 TEPCO released the result of the muon scan for Unit 1 which showed that no fuel was visible in the RPV, which would suggest that most if not all of the molten fuel had dropped onto the bottom of the PCV – this will change the plan for the removal of the fuel from Unit

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Each unit X subsection in the Accident section makes an abrupt shift from what happened during the accident to updates with more recent info. Most of the those updates are actually out of date now. Overall these sections should really just cover what happened at each unit during the accident.

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I updated this to cover the fact that fuel is still in the SFP, and there is a (long) plan in place for getting it out. However, I would appreciate some help understanding/summarizing the state of the fuel in/around the PCV as this report was a little too technical for me to feel comfortable

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small portion of tellurium, which are almost fully vaporized out of the core due to their low vapor pressure. The remaining fraction of deposited radionuclides are of less volatile elements such as barium, antimony, and niobium, of which less than a percent is evaporated from the fuel.

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with no shielding." Is very difficult to verify. The source is extremely technical. I have a bachelor's in physics and I cannot see how the source verifies this. That being said, I have good faith that is does say that, but the material is so complex that I think the claim boarders on

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There are a lot of reports/investigations related to this accident. If all of them are covered here this will be the longest article. With that in mind, I propose that this section only cover particularly notable investigations into subjects that are the main topic of other sections.

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indicates there was doubt about if there is still fuel in the RPV. It certainly would not be neutral to present "the entire core ... melted through the RPV". I propose that the prose is updated to summarize the diagram of unit 3 at the bottom of the 2017 muon study.

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area of the reactor since the meltdowns. TEPCO released images taken inside unit 2 by a remote-controlled camera that show a 2 m (6.5 ft) wide hole in the metal grating under the pressure vessel in the reactor's primary containment vessel, Later analysis indicated a

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signatures. From what I can tell, other sources give much more conservative estimates for the number of marches (7-8,000). I don't think UPI is 100% reliable on sensitive Japanese political issues given their Sun-Moon connections. Curious what others think.

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With this in mind, I propose to delete the below text. I think this investigation is no longer notable primarily because there have been more recent investigations that have better methodology for assessing the current state of the fuel. For example the

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The article currently talks about simulations of the melt into the concrete there is not reliable source for this so I am not sure what to make of this claim. TEPCO diagrams don't make this seem true, but they obviously have vested interests.

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building designed to support all of its systems independently for 72 hours in the event of an earthquake or severe flooding. This system was built prior to Fukushima Daiichi." I am interested in removing the source and reworking the claims.

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it as an "unexplained deletion". The move and deletion should have been done as two separate edits. Since you had explained it here, I will reconsider whether it should be deleted or not. In the meantime, I'll let other editors comment.

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I made a "Fuel Removal" subsection under Remediation and recovery to consolidate the info I discussed in this section as what is here clearly does not belong in descriptions of what occurred during the accident.

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process for Units 1, 2, and 3. With this scanning setup, it was possible to determine the approximate amount and location of the remaining nuclear fuel within the RPV, but not the amount and resting place of the

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Given that neither the national Diet report nor the IAEA accident report mention Beznau. I believe it is not sufficiently notable as a comparison. With this in mind I will be bold and remove the claims.

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Thanks for the comments. I am now going to delete the paragraph. I think long term this article, and potentially an article on accident tolerant, fuels need to be part of a series (in the formal

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for the content in the destination pages and must not be deleted as long as the copies exist. For attribution and to access older versions of the copied text, please see the history links below.

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the material. You should have mentioned the reason for the deletion in the edit itself (or at least directed editors to this section of the talk page that explains it). Hence, I

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summarizing it. One of the main points of confusion I have is: does all the fuel debris remain contained in the concrete base of the PCV or did some fuel melt down to the ground?

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Recommend that these sections are deleted or scaled back as the info is basically out of date and somewhat out of scope. However, I wanted to wait until better info is added:

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directed to research and development on nuclear safety, such as accident tolerant fuels that could withstand higher temperatures than conventional nuclear fuel."

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There is already some existing talk page discussion about what the source of the hydrogen gas for the unit 4 explosion was see Archieve 9 for more background.

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Suggestion: Move the Lawsuits out of the Fatalities/Injuries and the Infobox and to their own Subsection "Possible/Uncertain Radiation-Related Casualties"

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Updated about the fuel rods being removed. Stated decommissioning timeline for removing the debris. Boldly implemented the suggestion I explained above.

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The source for this claim is highly technical and it is not clear that it verifies the claims in the quoted paragraph below. I think this constitutes

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accumulating, as for about 1 day there was no water injection for Unit 1, while Unit 2 and Unit 3 had only a quarter of a day without water injection.

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Here is a quote of what is at the end of the unit one section now which I think is basically irrelevant. I think this could make good info for the

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The NAIIC report is currently cited as FN72. This needs page numbers for each time it is cited. This would be a great thing for a newcomer to do.

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I also checked (refs are defined in the article) which do not say that the mental health effects from this accident resulted in excess deaths.

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I think it should be removed since it is effectively a not very good summary of what is in the Reactors subsection of the Accident section.

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This is probably supposed to be from section 4.1 of the IAEA source FN9. However, it really says nothing like this and this seems like

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which has its own section on Reports which would be equivalent to an investigation section here. To me, that is sufficient guidance.

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I was hoping for the new sources to support the notability. Limiting my google search to 01/01/2011-01/01/2013 I searched:

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Harada, Nahoko; Shigemura, Jun; Tanichi, Masaaki; Kawaida, Kyoko; Takahashi, Satomi; Yasukata, Fumiko (2 September 2015).

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which has its own investigation section although I don't think it is particularly well done either. None of these are GA.

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venting was just one theory. However, I do think the spirit of claim is correct but additional sources are needed.

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And found no sources to support the notability of these claims. Therefore, I propose this section is deleted.

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https://apnews.com/article/japan-fukushima-daiichi-radioactive-water-release-75becaaf68b7c3faf0121c459fdd25af

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