Talk:Fukushima nuclear accident

nuclear accident : why not "nuclear disaster" ...

Hello, I am french, I write to you in english, learned at school, not very good, I wish you can understand... Fukushima disaster is more important than a so-called nuclear "accident". In french : accident nucléaire. Isn't it rather a nuclear "disaster", in french : catastrophe nucléaire. This is an important debate.

I wish the french wikipedia would write : CATASTROPHE nucléaire de Fukushima. Thank you for your response Evelyne Genoulaz 89.3.51.240 (talk) 08:08, 3 May 2024 (UTC)

This article used to be called Fukushima nuclear disaster, but it was moved after a discussion. See the link near the top of this page. As for French Wikipedia's title, that's not anything that English Wikipedia has any say over. Meters (talk) 08:15, 3 May 2024 (UTC)

missing talk page archives

talk page archives 14, 15, 16, 17, 18, and 19 are all red links. Not sure if this is the right spot to mention it, but oh well. Gaismagorm (talk) 19:12, 6 May 2024 (UTC)

Skeptical Inquirer not Reliable for scientific info

Unfortunately this is not listed in WP:RSP but based off Skeptical Inquirer I do not think this is a reliable source for scientific information. I am removing it in a few locations. The reason I am making such a stir about this is the structure of the section on Radiation Effects in Human is clearly inspired by the Skeptical Inquirer source.

• "a number of media reports incorrectly describing thousands of victims of tsunami as if they were victims of the "nuclear disaster" - Skeptical Inquirer is the only source for this claim. I think this is an example of the kind of non-scientific claim that it could be a reliable source for, but this seems like something that should have more sources.

• "Worldwide media coverage of the incident has been described as 'ten years of disinformation'" - Skeptical Inquirer is the only journal using this term this is not a widely held belief. If this POV was notable then it should have been attributed; however, this POV is not notable so I am removing it. I reworded the claim and moved it to the section on Germany's response since the source was talking about German media coverage.

Czarking0 (talk) 17:44, 19 May 2024 (UTC)

International Impact

As part of consolidating the two international impact sections, I removed this line because it was unsourced: "Responders included IAEA, World Meteorological Organization and the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization."

The CTBTO actually has some nice info on this that is probably notable to add back in with some appropriate sources. Think some non-state actors other than the IAEA would be notable. https://www.ctbto.org/news-and-events/news/fukushima-related-measurements-ctbto

This image was also removed. They don't really belong right now but I think they could be added back in the right context.

U.S. Navy humanitarian flight undergoes radioactive decontamination

Czarking0 (talk) 04:28, 3 June 2024 (UTC)

Changed Criticism To Prior Warning

Removed this bit since it did not fit

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 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.

Czarking0 (talk) 17:33, 3 June 2024 (UTC)

@Czarking0: You did not mention this deletion in the edit summary when you deleted 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 restored 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. --David Tornheim (talk) 20:19, 3 June 2024 (UTC)

My bad on not putting it in the edit comment.

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. Czarking0 (talk) 22:14, 3 June 2024 (UTC)

References

Investigations -- where to place in article

Made Its Own Section

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 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. --David Tornheim (talk) 20:26, 3 June 2024 (UTC)

I appreciate this remark and would support a move to its own section. I checked out 2021 Suez Canal obstruction which does not have a section on investigations and Francis Scott Key Bridge collapse which put the investigation section under the collapse which I do not think is great. I also looked at Chernobyl disaster which has its own investigation section although I don't think it is particularly well done either. None of these are GA.

I did look at Space Shuttle Challenger disaster which has its own section on Reports which would be equivalent to an investigation section here. To me, that is sufficient guidance. Czarking0 (talk) 22:12, 3 June 2024 (UTC)

I have taken this action Czarking0 (talk) 02:22, 26 June 2024 (UTC)

What to Have in Section

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.

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 muon tomography 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 investigating the accident itself.

TEPCO released estimates of the state and location of the fuel in a November 2011 report.[48] 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 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.[48]

"Additional deaths were attributed to subsequent stress or fear of radiological hazards"

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 am not a doctor) then this should be reworked. Czarking0 (talk) 03:12, 18 June 2024 (UTC)

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.

Here's a reference list with refs 2 and 3. – Daℤyzzos (✉️ • 📤) 12:31, 18 June 2024 (UTC)

References

Estimates of Spent Fuel Radiation

This quote from the article: "Undamaged spent fuel typically has values of 270 Sv/h, after ten years of cold shutdown 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 WP:OR. I am hoping other editors can weigh in on this. I did want to point out that the specific claim of radiation from unshielded fuel for 10 years has presumably never been measured in a controlled environment. To me, this indicates that the quantitative claim in the article is from some model, and expertise may be required in understanding if the model is valid in this case. Czarking0 (talk) 15:12, 22 June 2024 (UTC)

I updated the article with a better source. --TuomoS (talk) 16:00, 22 June 2024 (UTC)

 Courtesy reflist added by Daℤyzzos (✉️ • 📤) at 13:56, 23 June 2024 (UTC)

References

Status of Each Unit Since the accident

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. However, I do think the reader would appreciate a quick summary of what the status is now.

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.

Sources: https://www.tepco.co.jp/en/hd/decommission/project/roadmap/index-e.html https://www.tepco.co.jp/en/hd/decommission/progress/removal/unit1/index-e.html

I will describe the changes I make to each section below

Unit 1

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 Fukushima disaster cleanup page.

Deleted:

In February 2015, TEPCO started the muon scanning 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 corium 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 1.

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:

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 determine how far the fuel had eroded and diffused into the concrete, it was estimated that the fuel remained within the PCV.[48] 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."[49]

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 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?

Here are the sources I was looking into. https://www.iaea.org/sites/default/files/23/04/events-and-highlights-february-2023.pdf https://www.tepco.co.jp/en/hd/decommission/information/committee/pdf/2024/roadmap_20240425_01-e.pdf https://apnews.com/article/japan-fukushima-daiichi-radioactive-water-release-75becaaf68b7c3faf0121c459fdd25af

Unit 2

I am not sure what to do here. I was planning on resolving the easier cases first.

Unit 3

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.

"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, the 2017 muon study 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.

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

Unit 4

Just added that the rods were removed. Not much more to say here.

Czarking0 (talk) 23:31, 22 June 2024 (UTC)

Hydrogen Gas in Unit 4 Explosion

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.

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 venting was just one theory. However, I do think the spirit of claim is correct but additional sources are needed. Czarking0 (talk) 06:15, 23 June 2024 (UTC)

Radionuclide release sources and claims

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 WP:OR 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 this would be the longest page on WP.

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 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.

Czarking0 (talk) 15:37, 23 June 2024 (UTC)

References

UPI Figures on March and Petition

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 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. Czarking0 (talk) 15:24, 28 June 2024 (UTC)