82℃ in reactor2 → change the definition of cold shutdown

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Reactor 2 marked 82℃.

Tepco increased water amount by 1 tone on 2/11/2012, but increased it by additional 3 tones. Currently, they inject 17.6 tones /h (422.4 tones/d) .

Tepco also added 1 tone of boric acid. They haven’t measured Xe135, but they can’t control the situation.

They reported to NISA and local governments, because the heating gauge has 20℃ of error, 82℃ may mean 102℃ actually.

However, they stated it doesn’t affect the “cold shutdown” . On the press conference of 2/12/2012, Tepco announced they are going to change the definition of cold shutdown.

Tepco analyzes it’s because the heating gauge is broken because other 2 heating gauges are showing 34℃. Source



  1. If water temperature is 102C, we must see some steam coming out of the reactor (from live cam)?
    “thermometers’ margin of error of up to 20 degrees” could mean +-20C or something between that.

    Truth is that temperature is rising. I hope that they find a solution ASAP.

    Nice blog, thanks.

    1. “At 15:30 Tepco increased the injection rate by 3 tons/hour to 17.4 tons/hour. No xenon detected.”
      So they measured Xe, I think?

      1. Dear Mochizuki, there is a claim by TEPCO of 20C margin of error. Does anyone know what is the confidence interval and is there a problem with TEPCO’s hypothesis testing?

  2. Hi,

    Thank you for bringing this to people’s attention and I wish everyone a speedy way out of this continually unfolding nightmare. It breaks my heart to see this happening.

    I’m not sure how 1 company in Japan, TEPCO, can change the definition of a “cold shutdown”. It is something defined by several countries. Maybe this is something lost in translation.

    I do have a problem with the whole “cold shutdown” story though – I think it’s a confidence trick.

    It has been many months since there was a meltdown of the fuel inside the reactors, it has been many months of cooling and heating and then cooling again. I am far from being an expert but from the research I’ve done and a bit of logic it seems to me thatif I cold shutdown had occurred then there would be a general downward trend in the temperatures. This does not seem to be the case, it looks like the temperatures are having greater peaks which surpass earlier temperatures. That to me simply looks like a situation where the fuel is still generating a rising amount of heat and is being cooled to varying success but never actually being shutdown. Isn’t this pretty much what a nuclear power station does? Except this looks desperate. I mentioned “fuel” rather than “reactor”. The reason for that is: I am not convinced that the fuel is still inside the reactor, can anyone give me evidence to suggest that it is?

    I’ve been looking at the definition of a “cold shutdown” and I think that the definition is open to abuse. The definition regards the temperature of the reactor, not the fuel. Therefore if the fuel is no longer in the reactor, there may be technically a “cold shutdown”, yet the fuel could be at the bottom of the concrete drywell with fission occurring (as suggested by the presence of Xenon).

    In the situation where the fuel is no longer in the reactor, a “cold shutdown” may give no real comfort- it may be a distraction from the real danger.

    Apologies if I’ve misunderstood anything, it’s difficult to get news on the situation let alone understand the technical nature of it.

    If anyone can put me right, tell me I’m wrong – I’d be most grateful. I hope that I am wrong.

    Many thanks,


    1. How about this: “Nuclear Oriented Bad Science” = NOBS or better yet! N☢ BS…?
      Why does TEPCO and the Japanese Gov’t want to declare it’s Fukushima disaster Stable and more importantly, what do they hope to accomplish by doing it now?

      A. If the people “swallow” this Nuclear Baloney (NB) then TEPCO and their other Gov’t Leaders get to keep their jobs and march onward toward a nuclear future while the Nuclear refugees are “encouraged” to return to their Fukushima homes; letting history be the judge of whether or not this was the RIGHT decision.

      B. The people of Japan reject the concept of a “cold shut down” in which case TEPCO, in time, gets nationalized and Japan develops a 20 year plan to replace it’s reactors with solar of all flavors!

      C. The people of Japan are insulted by what TEPCO and their Gov’t is saying and take to the streets to DEMAND immediate change. TEPCO and their Government overseers are both swept away in order to placate the people of Japan. The Nuclear Refugees get settlements and the area around Fukushima is closed to all but scientific personal for the foreseeable future. Japan’s PM pledges to “race” Germany toward New Japanese developed Solar and being Nuclear within FIVE years…

      The Japanese people are now at a cross roads that will define both their future,their children’s future and possibly the future of Nuclear Power on Earth!

      What will they now do:
      …Bow to TEPCO?
      …Accept their Leaders vow to do better?
      …Or Demand an end to using Nuclear ASAP?

  3. How can you have cold shut down without a “reactor”?

    There are only three piles of radioactiv­e junk in Fukushima and those are no longer reactors!
    If a tank blows up you have a burned out hulk or mass of scrap but you don’t have a tank any more; that ceased to exist when it blew up…

    RE: Cold Shutdown:
    It is a misuse of the term to describe a reactor after meltdown as ‘in cold shutdown’. As the fuel assembly is destroyed no shutdown is possible. Fuel is melted together and impossible to control directly. Even if pressure and temperatur­­e are unalarming momentaril­­y ‘cold shutdown’ implies complete control which is impossible after meltdown.

    Why can’t the Nuclear Industry accept that a melted down reactor is not a normal condition for a reactor which is shut down for any number of reasons and is ABLE TO BE STARTED UP AGAIN SAFELY!
    This is a perfect example of Nuclear Oriented Bad Science (N☢ BS) being used to provide dis-inform­ation to the public and only serves to call into question those in the Industry that should be speaking out against this Nuclear Baloney (NB)!

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About this site

This website updates the latest news about the Fukushima nuclear plant and also archives the past news from 2011. Because it's always updated and added live, articles, categories and the tags are not necessarily fitted in the latest format.
I am the writer of this website. About page remains in 2014. This is because my memory about 311 was clearer than now, 2023, and I think it can have a historical value. Now I'm living in Romania with 3 cats as an independent data scientist.
Actually, nothing has progressed in the plant since 2011. We still don't even know what is going on inside. They must keep cooling the crippled reactors by water, but additionally groundwater keeps flowing into the reactor buildings from the broken parts. This is why highly contaminated water is always produced more than it can circulate. Tepco is planning to officially discharge this water to the Pacific but Tritium is still remaining in it. They dilute this with seawater so that it is legally safe, but scientifically the same amount of radioactive tritium is contained. They say it is safe to discharge, but none of them have drunk it.


February 2012