Tepco mishandled coolant water injection to reactor3 to increase by 20% suddenly, “touched a valve mistakenly”

According to Tepco, coolant water injection to reactor3 spiked up by 20% suddenly. WSJ reported it was because a nuclear worker touched a valve mistakenly when they took out the heat insulating material nearby the valve.


↓ Tepco’s report about the mishandling.

Press Release (Nov 26,2012)

Increase in the Reactor Injection Water Amount at Unit 3 of Fukushima Daiichi Nuclear Power Station

Though water injection into Units 1-3 reactors at Fukushima Daiichi Nuclear Power Station is continuously done by the regular use reactor injection system, a TEPCO employee found that Unit 3 reactor injection water amount had increased from 5.8m3/h (as of 10:00 AM) to 7.0m3/h at 11:00 AM today during the regular data check.

The technical specification for the nuclear reactor facility*1 stipulates that an increase amount of reactor injection water from the regular use reactor injection system must be 1.0m3/h or less during any given 24 hours as an “operational requirement”*2.

Since the increase of Unit 3 reactor injection water exceeded 1.0m3/h, the shift supervisor on duty judged that the condition did not fulfill the “operational requirement” stipulated by the technical specification for the nuclear reactor facility at 11:00 AM.

As the “required measure to be taken” for this incident is to start implementing measures to reduce the increase amount of reactor injection water down to the allowed range, the reactor injection water amount at Unit 3 was set back to 6.0m3/h at 11:10 AM.

Unit 3 PCV gas control system indicates no change in xenon 135 density which is below the detection limit (3.4×10-1 [Bq/cm3]) and subcritical.

There has been no significant change in the monitoring post data and no leakage around the injection line between the regular use reactor injection system and the building entrance. The reactor injection water amounts at Units 1 and 2 remain stable.

We will investigate the cause of the incident and implement necessary measures.



Source 1 2




Français :

Erreur de Tepco sur l’eau du système de refroidissement du réacteur 3 qui a soudain augmenté de 20 %, “on a bougé une vanne par erreur”

Selon Tepco, l’injection d’eau de refroidissement dans le réacteur 3 a soudain augmenté de 20 %. WSJ a rapporté que c’est parce qu’un ouvrier a touché une vanne par erreur quand ils retiraient de l’isolant de chaleur près de cette vanne.

↓ Le rapport de Tepco sur cette erreur de manip.

Communiqué de Presse (26 Nov 2012)

Augmentation de la quantité de l’eau injectée dans l’unité 3 de la station électrique nucléaire de Fukushima Daiichi

Bien que l’injection d’eau dans les unités des réacteurs 1 à 3 de la station électrique de Fukushima Daiichi soit faite de façon continue par l’utilisation régulière du système d’injection du réacteur, aujourd’hui pendant le contrôle normal des données, un ouvrier de TEPCO a remarqué que la quantité d’eau injectée dans le réacteur 3 était passée de 5,8 m³/h (à 10:00 AM) à 7,0 m³/h à 11:00 AM.

Les spécifications techniques de l’équipement du réacteur nucléaire*1 stipulent qu’en usage normal du système d’injection d’eau, l’augmentation de la quantité d’eau injectée dans le réacteur doit être, par tranche de 24 heures et en tant que “nécessité opératoire”, de 1,0 m³/h ou moins *2.

Puisque l’augmentation de l’injection de l’eau dans le réacteur de l’unité 3 dépassait les 1.0 m³/h, le superviseur de service a jugé à 11:00 AM que les conditions ne suivaient pas parfaitement les “nécessités opératoires” telles que définies dans les spécifications techniques de l’appareillage du réacteur nucléaire.

Comme les “mesures exigées à prendre” pour cet incident sont d’appliquer des mesures de réduction de la quantité d’eau injectée dans le réacteur jusqu’à atteindre le niveau autorisé, la quantité d’eau injectée dans le réacteur 3 a été ramenée à 6 m³/h à 11:10 AM.

Le système de contrôle des gaz de l’enceinte de confinement primaire (PCV) de l’unité 3 indique qu’il n’y a pas de changement de la densité en xénon 135 qui reste en-dessous de la limite détectable (3,4×10-1 [Bq/cm³]) et sous-critique.

Il n’y a eu aucun changement significatif des données enregistrées par la borne de surveillance et aucune fuite n’est à signaler autour de la ligne d’injection entre l’utilisation normale du système d’injection du réacteur et l’entrée du bâtiment. La quantité d’eau d’injection dans les réacteurs des unités 1 et 2 reste stable.

Nous allons enquêter sur la cause de cet incident et prendre les mesures nécessaires.


Sources : 1 2

  1. They are playing with their own lives (and of their whole nation) like *upid children.
    Today I’ve seen how clumsily they manage a crane of them (the only one operating, btw, today), waving the hook all around out of control.
    It seems that not only the daily temblors may cause another disaster right there.

  2. ブログよく読ませていただいています。ありがとうございます。フィラデルフィアにお立寄の際にはぜひご連絡ください。狭い所に住んでいるのでお宿は提供できませんが、微力ながら何らかの形で応援させていただきたいと思っています。お体に気をつけてご活動ください。

    1. どうもありがとうございます。再訪米の際にはぜひお声かけさせていただきたいと思います。よろしくお願いします。

  3. It seems to me that a increase of that value is more than a few turns of the valve and would be hard to do without the persons knowledge? BS

  4. Limited hangout, yes maybe more water, no to the rest, ie “no xenon etc”
    Just to be clear, the reactor control rods “silver” has been found allover and in everything ie “radioactive silver in spiders etc” there is no way the melted fuel isn’t fissioning. Take that to the bank. No control rods + 20 million horsepower heat equivalent sub 100 ton reactor load = whoa mama.

  5. What part of “lying assholes” do people not understand. This has always been quite ridiculous facetious fictitious, what we know 3 cores in the ground and until proven otherwise 4 spent fuel pool fires, and I say reac3 blew it’s whole core out like a cannon so I can’t say it’s under the reactor somewhere with confidence«of which I have none in much of anything anymore. God it hurts, rue my humanity like some backwoods hermit.

  6. Maybe next time some worker from who knows where that knows fk all will turn it the other way? What a Roll OF THE DICE baby whooping, that was a close 1 huh. 1 hour between checks it says… I’d have a live data flowmeter feed myself but then again I don’t have a nuclear reactor and the world isn’t depending on me not to forget up but what do I know.

  7. You like how they tell the guy to turn the knob etc and check the flow rate all “laissez faire” an hour later. This “world’s largest nuclear plant built directly above a fault line” is going to the final destination and so’s japan, the behavior is the crystal ball/the predictor, the truth teller, insight into how this will work out/end. You cannot ###k around with this **#t, it cannot be stressed enough, that whole site almost went nuclear inferno for the “I’ve lost count” time. Yes really.
    That’s so raven.
    /Amanda please.

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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.


November 2012