[Video] Water level in Reactor 1 decreased 350 mm in 2.5 years

From Tepco’s report published on 5/28/2015, the water level in PCV 1 (Primary Containment Vessel of Reactor 1) has decreased by 350 mm since October of 2012.


Tepco originally has been planning to put the molten fuel of Reactor 1 in “water tomb” by filling the PCV with water.

They control the water level by balancing the leaking volume and injecting level. However from the recent survey implemented this April, the water level was 350mm lower than last time they surveyed in 2012.

The state of the inside of PCV has not been investigated, however Tepco states still the reactor is under control and the decrease of water level is not affecting the coolant situation.


Tepco still hasn’t investigated how much coolant water is leaking out of the vessel. However they explained probably it was because they reduced the water injection volume from 5.0 m3/h to 4.5 m3/h in November of 2012.








Français :

[Vidéo] Le niveau d’eau du réacteur 1 est descendu de 350 mm en 2,5 ans


Selon un rapport de Tepco publié le 28 mai 2015, le niveau d’eau de la PCV 1 (Primary Containment Vessel of Reactor 1 = Enceinte primaire du réacteur 1) a diminué de 350 mm depuis octobre 2012.

Au départ, Tepco avait prévu de maintenir le combustible fondu du réacteur 1 dans une “tombe d’eau” en noyant la PCV dans l’eau.
Ils contrôlent le niveau de l’eau en faisant la différence entre ce qui en fuit et ce qu’ils y injectent. Cependant, à la suite d’une récente exploration effectuée en avril dernier, le niveau était 350 mm en-dessous de ce qu’ils en avaient vu la dernière fois, en 2012.
L’état de l’intérieur de la PCV n’a pas été établi, néanmoins Tepco affirme toujours que le réacteur est sous contrôle et que la diminution du niveau d’eau n’impacte pas le refroidissement.

Tepco n’a toujours pas établi le volume des fuites du liquide de refroidissement hors de l’enceinte. Néanmoins, ils expliquent que c’est parce qu’en novembre 2012 ils ont réduit le volume d’eau injectée de 5 m³/h à 4,5 m³/h.


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.


June 2015