Fukushima Daiichi nuclear disaster discussions

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Discussion Overview

The discussion revolves around the Fukushima Daiichi nuclear disaster, focusing on various aspects including technical details of the nuclear plants, regulatory responses, radiation detection, and the management of the crisis. Participants explore the implications of the disaster, the ongoing challenges related to radioactive water, and the stability of the reactor debris over time.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants inquire about the methods used to calculate hazardous-emergency distances from the Fukushima accident, referencing radiation measurements in Rem or mR.
  • Others express curiosity about the continuous pumping of water into the reactors, questioning whether sealing the site with concrete, similar to the Chernobyl approach, could be a viable solution.
  • There are discussions about the necessity of injecting cooling water into the reactors, with some suggesting that after 13 years, the fuel and debris may have stabilized and decay heat should be low.
  • A participant shares a decay heat estimation, suggesting that the current decay heat is significant enough to require continued cooling, despite the passage of time.
  • Some participants reference various threads and resources related to the disaster, including regulatory actions and open-access publications on the consequences of the accident.

Areas of Agreement / Disagreement

Participants express differing views on the necessity and implications of ongoing water injection into the reactors, with some questioning its relevance after many years and others emphasizing the potential risks of not doing so. There is no consensus on the best approach to managing the site or the stability of the reactor debris.

Contextual Notes

Discussions include uncertainties regarding the stability of reactor debris and the effectiveness of current cooling methods. Participants highlight the complexity of the situation, with various assumptions about decay heat and the physical state of the materials involved.

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There are several threads related to the disaster:

Japan Earthquake: nuclear plants - technical aspects of the situation at the Fukushima Daiichi NPP (and other plants).

Japan Earthquake: nuclear plants part 2 - technical aspects of the situation at the Fukushima Daiichi NPP (and other plants) - part 2 (thread split on September 20th, 2013 for performance reasons).

The "more political thread" besides "Japan Earthquake: nuclear plants" scientific one - discussion about the way crisis was managed both by engineers/management at place and Japanese government.

Fukushima Management and Government Performance

Why is Fukushima nuclear crisis so threatening?

Fukushima radiation detection and measurement

Japan earthquake - contamination & consequences outside Fukushima NPP

Please keep your posts in each thread on topic.
 
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Engineering news on Phys.org
Actions taken by regulatory bodies following the Fukushima Daiichi nuclear accident
http://www.oecd-nea.org/nsd/fukushima/

Collection of information published on various websites (TEPCO, IAEA, NISA, WNN, Nucnet, IRSN, GRS, etc.)
https://clearinghouse-oef.jrc.ec.europa.eu/prompt-notifications/fukushima-nuclear-accident/daily-updates-on-the-situation
 
Last edited by a moderator:
Astronuc said:
Actions taken by regulatory bodies following the Fukushima Daiichi nuclear accident
http://www.oecd-nea.org/nsd/fukushima/

Collection of information published on various websites (TEPCO, IAEA, NISA, WNN, Nucnet, IRSN, GRS, etc.)
https://clearinghouse-oef.jrc.ec.europa.eu/prompt-notifications/fukushima-nuclear-accident/daily-updates-on-the-situation



how can I find the activity of isotope which it has in area given value mCi or mR or Rem value of this? ionization energy of isotope how many distance can it travel on air and in earth-ground when I know only the Curi or Rem or Roengen?

ex. Who they calculate the hazardous-emergency distance from Fukushima accident?
 
Last edited by a moderator:
Dears! ,

thanks, but, may you have an aprox. number in Rem or mR or Ci by distance?
e.x 800mR radiation source can ionize everything up to 1m
 
Borek said:
There are several threads related to the disaster:

Japan Earthquake: nuclear plants - technical aspects of the situation at the Fukushima Daiichi NPP (and other plants).

Japan Earthquake: nuclear plants part 2 - technical aspects of the situation at the Fukushima Daiichi NPP (and other plants) - part 2 (thread split on September 20th, 2013 for performance reasons).

The "more political thread" besides "Japan Earthquake: nuclear plants" scientific one - discussion about the way crisis was managed both by engineers/management at place and Japanese government.

Fukushima Management and Government Performance

Why is Fukushima nuclear crisis so threatening?

Fukushima radiation detection and measurement

Japan earthquake - contamination & consequences outside Fukushima NPP

Please keep your posts in each thread on topic.
Newer item: Springer published a free-downloadable book 2014 caled "Reflections on the Fukushima Daiichi Nuclear Accident" made as a result of a cooperation between Berkeley and Univ. of Tokyo.
 
Mickey1 said:
Newer item: Springer published a free-downloadable book 2014 caled "Reflections on the Fukushima Daiichi Nuclear Accident" made as a result of a cooperation between Berkeley and Univ. of Tokyo.
Springer published a number of open-access (i.e., free downloads) texts on the consequences of the Fukushima accident.

Reflections on the Fukushima Daiichi Nuclear Accident
https://link.springer.com/book/10.1007/978-3-319-12090-4
Radiation Monitoring and Dose Estimation of the Fukushima Nuclear Accident
https://link.springer.com/book/10.1007/978-4-431-54583-5
Impacts of the Fukushima Nuclear Accident on Fish and Fishing Grounds
https://link.springer.com/book/10.1007/978-4-431-55537-7
Agricultural Implications of the Fukushima Nuclear Accident
https://link.springer.com/book/10.1007/978-4-431-54328-2
Agricultural Implications of the Fukushima Nuclear Accident
The First Three Years
https://link.springer.com/book/10.1007/978-4-431-55828-6
Agricultural Implications of the Fukushima Nuclear Accident (III)
After 7 Years
https://link.springer.com/book/10.1007/978-981-13-3218-0
Radiological Issues for Fukushima’s Revitalized Future
https://link.springer.com/book/10.1007/978-4-431-55848-4
Earthquakes, Tsunamis and Nuclear Risks
Prediction and Assessment Beyond the Fukushima Accident
https://link.springer.com/book/10.1007/978-4-431-55822-4
 
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I'm pondering on why Fukushima site continues pumping millions of tonnes of water every day into the destroyed reactor thus creating waste water daily? Can they seal the site with concrete like soviet did at Chernobyl?
 
Tepco's site says
cooling water is being continuously injected into the reactors and keeping the debris stable.
I'm also wondering about the necessity to pump water into the sites. Presumably now, after some 13 years, any fuel/concrete mass has now solidified, and is stable, and decay heat should be sufficiently low to prevent anything unexpected from happening, but maybe not?
 
  • #10
Gary7 said:
Tepco's site says
Can you please link to the discussion about injecting cooling water.
 
  • #12
Gary7 said:
Presumably now, after some 13 years, any fuel/concrete mass has now solidified, and is stable
As fuel, in known geometric configuration it would be already safe for dry cask storage.
But as debris, it's just a big unknown: if there are enough material around as insulation, the inner temperature might be still high.

Also, based on that infamous 'elephant foot' in Chernobyl it is known that this kind of material is not necessarily stable and might degrade with time => to prevent any particles going airborne it's just better to keep it submerged.
 
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  • #13
My decay heat spreadsheet estimates the 13 year (400 million seconds) power fraction as 6x10-5 (maybe someone else can check this order of magnitude). Assuming BWR-4 initial power at 3000 MWth, that would give a present decay heat of ~600,000 Btu/hr (176 kW). if the injected water boils, it would need about 1.1 gpm (0.25 m3/hr). This is a trickle.
 

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