The first robot that entered Reactor 1 died in 5 hours

Following up this article.. Tepco started stating molten fuel might be out of pedestal of Reactor 1 [URL]


On 4/10/2015, Tepco announced their first robot for Reactor 1 stopped moving after traveling approx. 10m.


In order to investigate the possibly overflowed molten fuel, Tepco put a robot into PCV (Primary Containment Vessel) to Reactor 1.

This robot forms itself like a train (60cm, 7cm, 9.5cm) to go through a penetration pipe. It deploys itself in the shape of “C” when it reaches the ground floor of PCV.

It was around 9AM of 4/10/2015 when Tepco started the investigation. They managed to land the robot onto the ground floor of PCV, however it stopped around 2PM. It moved only for approx. 10m.


They planned to collect the images, temperature and dose data of Reactor 1. They reported 2/3 of planned data was collected, however did not announce what the robot found.

The specific cause to have stopped the robot is not identified. Tepco is commenting some cable could have been stuck somewhere.


In the investigation of October 2012, they measured 11.1 Sv/h inside of the PCV.


2 The first robot that entered Reactor 1 died in 5 hours


3 The first robot that entered Reactor 1 died in 5 hours


The first robot that entered Reactor 1 died in 5 hours



(Iori’s note : There could be a possibility that the robot didn’t die, but was “killed” because it found something inappropriate.)


Français :

Le premier robot introduit dans le réacteur 1 est mort en 5 heures


Article lié : Tepco commence à dire que du combustible fondu pourrait avoir traversé le piédestal du réacteur 1

Le 10 avril 2015, Tepco annonce que leur premier robot pour le réacteur 1 a arrêté de bouger après un déplacement d’environ 10 m.

Tepco avait mis un robot dans la PCV (Enceinte de confinement primaire du réacteur 1 pour examiner les probables écoulements de combustible fondu.
Ce robot ressemble à un train (60 cm, 7 cm, 9,5 cm) pour entrer par un tuyau. Il s’est déployé en forme de “C” lorsqu’il a atteint le sol dans la PCV.
Il était environ 09:00 le 10 avril 2015 lorsque Tepco a commencé son exploration. Ils ont réussi à faire attérir le robot sur le sol de la PCV mais il s’est arrêté vers 14:00 après avoir seulement parcouru 10 m environ.

Ils prévoyaient de récolter des images, les temperatures et les doses du réacteur 1. Ils disent que 2/3 des données attendues ont été récoltées mais ils ne disent pas ce que le robot a trouvé.
La raison exacte qui a arrêté le robot n’est pas identifiée. Tepco déclare qu’un cable a pu être coincé quelque part.

Lors de l’exploration d’octobre 2012, ils avaient relevé 11,1 Sv/h dans la PCV.

2 The first robot that entered Reactor 1 died in 5 hours
3 The first robot that entered Reactor 1 died in 5 hours
The first robot that entered Reactor 1 died in 5 hours

(Note de Iori : Il est possible que ce robot ne soit pas mort mais il a été “tué” parce qu’il a rencontré quelque chose d’inattendu.)

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.


April 2015