TOKYO, May 15, Kyodo
A nuclear fuel meltdown at the No. 1 reactor of the crisis-hit Fukushima Daiichi power plant is believed to have occurred around 16 hours after the March 11 quake and tsunami crippled the complex in northeastern Japan, Tokyo Electric Power Co. said Sunday.
The utility revealed its study on the subject on Sunday.
TEPCO said it analyzed the data and calculated a timeline for the developments in the No. 1 reactor on the assumption that the reactor lost its cooling system as soon as it was hit by the tsunami.
The firm said that within about 3 hours after the reactor automatically shut down, the cooling water had evaporated to a level at the top of the rods.
In the next hour and a half, parts of the fuel rods are believed to have begun melting.
The temperature of the fuel rods is believed to have reached 2,800 degrees Celsius at this stage, and the meltdown advanced rapidly.
Almost of all the fuel rods melted and dropped to the bottom of the pressure vessel by 6:50 am on March 12th.
TEPCO said the temperature dropped after water was poured into the reactor starting at 5:50 am on the same day.
The firm says the melted rods created small holes on the bottom of the vessel, but that no major problems are developing there. It believes that the amount of radioactive substances that could spread from the reactor will be limited.
TEPCO said it analyzed the data and calculated a timeline for the developments in the No. 1 reactor on the assumption that the reactor lost its cooling system as soon as it was hit by the tsunami.
The firm said that within about 3 hours after the reactor automatically shut down, the cooling water had evaporated to a level at the top of the rods.
In the next hour and a half, parts of the fuel rods are believed to have begun melting.
The temperature of the fuel rods is believed to have reached 2,800 degrees Celsius at this stage, and the meltdown advanced rapidly.
Almost of all the fuel rods melted and dropped to the bottom of the pressure vessel by 6:50 am on March 12th.
TEPCO said the temperature dropped after water was poured into the reactor starting at 5:50 am on the same day.
The firm says the melted rods created small holes on the bottom of the vessel, but that no major problems are developing there. It believes that the amount of radioactive substances that could spread from the reactor will be limited.
Sunday, May 15, 2011 23:29 +0900 (JST)
Nessun commento:
Posta un commento