Sunday, April 17, 2011

#Fukushima I Nuke Plant: iRobot Readings of Reactors 1 and 3

From TEPCO's press conference on April 18 morning (in Japanese). TEPCO says they are provisional data.

Reactor 1 building:

Date and time: 4:40PM to 5:30PM, April 17, 2011
Radiation (1st floor, through the north door): 10 to 49 milli-sievert/hr
Temperature: 28 to 29 degrees Celsius
Humidity: 49 to 56%
Oxygen level: 21%

Reactor 3 building:

Date and time: 11:30AM to 1:30PM, April 17, 2011
Radiation: 28 to 57 milli-sievert/hr
Temperature: 19 to 22 degrees Celsius
Humidity: 32 to 35%
Oxygen level: 21%

According to TEPCO, there were a lot of debris inside the Reactor 3 building, and the robots had a hard time moving forward and didn't go much beyond the door.

TEPCO also did the dust sampling.

Part of the reason why they had the robots enter through the north door was because of the high radiation level at the south door.

On April 16, the radiation level at the south door to the Reactor 1 building was measured at 270 milli-sievert/hr. The distance between the north door and the south door is about 30 meters, according to TEPCO. The radiation right outside the north door was also measured on April 16, and it was 20 milli-sievert/hr.

This was the first time the radiation level was measured inside the Reactor buildings (other than Reactor 4 building) since the March 11 earthquake.

The annual limit for radiation exposure for nuclear plant workers has been raised to 250 milli-sievert/year after the Fukushima I Nuke Plant accident. Working in the Reactor 3 building for 5 hours would exceed that number.


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