[Spare contaminated water] 20,000m3 of highly contaminated water still retained in seawater trenches,”4.2 tera Bq/m3″

According to Tepco, there is still 15,000 ~ 20,000 m3 of extremely highly contaminated water still retained in the seawater trenches.

The trenches are located in the seaside of reactor2 ,3 and 4. The radiation level of the retained water in the trench of reactor2 was 4.2×10^12 Bq/m3 in March of 2011. It is not announced about other trenches.

The sizes of each trench are below,

Reactor2 : Diameter, 4m / Length, 300m

Reactor3 : Diameter, 4m / Length, 250m

Reactor4 : 2m×2m / Length, 100m (There are 2 trenches)


At this moment Tepco plans to remove the retained water in 2020.

On 5/30/2013, the committee of experts urged Tepco to remove the retained water ahead of the plan. However the trenches are connected to the turbine buildings, where contaminated water is also retained. In order to implement it, Tepco needs to isolate the trenches from the buildings somehow. They also need the technical development to save nuclear workers from extremely high level of radiation.

Additionally Tepco is trying to decrease the volume of ground water to flow into the plant. However, if they make the water level of ground water lower than the water level inside of the plant, contaminated water overflows backward from the inside of the plant. On the other hand, if they decrease the volume of water inside of the plant to make the water level lower than the seawater trench, 4.2 tera Bq/m3 of contaminated water flows into the plant as well. Tepco is forced to struggle to take the balance.





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Français :

[Eaux extrêmement radioactives] 20 000 m³ à 4,2 Téra-Bq/m³ sont toujours retenus dans des tranchées d’eau de mer

Selon Tepco, il reste toujours de 15 à 20 000 m³ d’eau extrêmement radioactive dans des tranchées d’eau de mer.

Ces tranchées sont situées sur le côté mer des réacteurs 2, 3 et 4. En mars 2011, le niveau de radioactivité des eaux  de la tranchée du réacteur 2 était à 4 200 000 000 000 Bq/m³. Rien n’est communiqué sur les autres.

Les tailles de ces tranchées sont les suivantes :
Réacteur 2 :  4 m de diamètre /  Longueur de 300 m
Réacteur 3 :  4 m de diamètre /  Longueur de 250 m
Réacteur 4 :  2×2m / Longueur de 100 m (Il y a 2 tranchées)

Pour l’instant Tepco prévoie de vider ces tranchées en 2020.

Le 30 mai 2013, le comité d’experts a pressé Tepco de les vider plus tôt que prévu. Or elles sont reliées aux bâtiments des turbines où il y a aussi de l’eau extrêmement radioactive. Pour les vider, Tepco doit les isoler des bâtiments d’une façon ou d’une autre. Ils ont aussi besoin d’une technique pour préserver les travailleurs de ces niveaux extrêmement élevés de radioactivité.
En outre, Tepco essaye de réduire le volume des eaux souterraines inondant la centrale. Or, s’ils font baisser leur niveau en-dessous de celui de l’intérieur de la centrale, des eaux extrêmement radioactives vont s’écouler vers l’extérieur. De plus, s’ils fond baisser le volume des eaux de l’intérieur en dessous de celui des tranchées, ces eaux à 4,2 Tera-Bq/m³ vont s’écouler dans la centrale. Tepco est obligée de se battre pour trouver un équilibre.



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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.


June 2013