Mars 2011: Kärnkraftverket i Fukushima - utbruten och sammanfogad tråd

TEPCO: Just 60cm of water in Fukushima reactor

Tokyo Electric Power Company says it has found that the cooling water in one of the damaged reactors at Fukushima is only 60 centimeters deep, far lower than previously thought.

The utility confirmed the water level by inserting an endoscope into the No.2 reactor at the Fukushima Daiichi nuclear power plant on Monday.

TEPCO had thought that the water level was about 3 meters. It has been injecting nearly 9 tons of water per hour into the reactor to cool the melted fuel that has fallen to the bottom of the containment vessel.

But the shallow level indicates that the water continues to leak into the reactor building through the suppression chambers under the vessel.

The utility argues that the fuel is still being cooled, as the water temperature remains at around 48 degrees Celsius.

But the low level suggests that decommissioning the reactor could be much more difficult. The operator may need to repair more parts of the containment vessel so it can be filled with water to block the strong radiation.

The No. 2 reactor's containment vessel is believed to have been damaged on March 15th with the sudden loss of pressure inside the reactor.

Monday's survey was the second look inside the No.2 reactor since January. During the first survey, an endoscope was unable to confirm the water level in the containment vessel. This time, TEPCO used a scope that is 10 meters longer.
Monday, March 26, 2012 21:40 +0900 (JST)

Lethal radiation detected inside Fukushima reactor

Tokyo Electric Power Company has detected extremely high levels of radiation inside one of the crippled reactors of the Fukushima Daiichi nuclear power plant.

TEPCO was able to place monitoring equipment directly inside the reactor for the first time since last year's accident.

A dosimeter lowered into the containment vessel of the No.2 reactor registered 72.9 sieverts, or 72,900 millisieverts per hour at maximum -- a level where a human is certain to die within about 7 minutes of exposure.

The utility hopes to determine the state of the vessels as it moves to decommission the reactors.

It says radiation levels increased as the dosimeter was lowered inside the reactor. This suggests the nuclear fuel melted down and collected at the bottom of the vessel.

The utility also learned the water level inside the vessel was only 60 centimeters, compared to the original estimate of about 3 meters.

TEPCO suspects the suppression chamber at the bottom of the vessel may have been destroyed.

The findings are a setback for plans to scrap the reactor. The utility has to pinpoint and repair damaged parts inside the vessel and fill it with water before extracting the fuel.

TEPCO says the development of devices that can withstand the extremely high levels of radiation is a pressing matter.
Wednesday, March 28, 2012 11:13 +0900 (JST)