NHK journalists who were investigating the radiation data from the Fukushima nuclear disaster found abnormalities in the radiation data from Fukushima Daini. After asking TEPCO for clarification, the utility revealed the existence of data related to a period between March 15th and April 3rd, 2011, which until this point had been undisclosed.
On March 16th, NHK reported that white smoke had arisen from the Fukushima Daiichi Unit 3 reactor building and rising radiation levels caused the evacuation of workers on-site. The billowing white smoke was caught on camera by an NHK helicopter some 30 kilometers away. Around an hour later, radiation levels at the Fukushima Daini plant then dramatically jumped from 20 microsieverts per hour to 80 microsieverts per hour. The relationship between the visible release and the increase in radiation levels is now being investigated.
TEPCO officials said “We are investigating why the data were not released. We’ll study a release of these data as the investigation progresses”.
Kado Shinichiro of Tokyo University said, “For analysis, it is highly regrettable that unreleased data come out one year and 8 months after the accident. It is necessary to check the data, including the relationship between the peak and the white smoke at unit 3”.
What officials said on March 16th, 2011
Chief cabinet secretary Yukio Edano has described problems that occurred on the morning of 16 March with Fukushima Daiichi 3 and 4, as well as plans to pump water into unit 4. Controlling the situation of the used fuel storage ponds is the urgent priority now.
At 8.34am white smoke was seen billowing out of Fukushima Daiichi 3. Efforts to determine the cause of this development were interrupted by the evacuation of workers after rising radiation readings. Readings from a sensor near the front gate had fluctuated for some time, although Edano said that on the whole there was no health hazard. Earlier in the morning readings had ranged between 0.6-0.8 millisieverts per hour, but at 10am readings rose to 1.0 millisieverts per hour before falling again just before 11am.
Edano said that one possibility being considered was that the unit 3 reactor had suffered a similar failure to that at unit 2 yesterday, where the torus pressure suppression structure is suspected of being damaged. However, there had been no reported blast or loud sound, which had been the case for unit 2. The immediate focus, said Edano, was on monitoring of water levels and checking pumping operations.
Source: World Nuclear News
“URGENT: UPDATE1: Fukushima No.3 reactor’s container feared damaged: Edano
TOKYO, March 16, Kyodo
The container of the No.3 reactor of the quake-hit Fukushima No.1 nuclear power plant is feared to have been damaged and may have leaked radioactive steam Wednesday, emitting high-level radiation, Chief Cabinet Secretary Yukio Edano said.
The radiation level briefly topped 2 milisievert at the plant, its operator Tokyo Electric Power Co. separately said.
The explanations were given after smoke was seen rising from the No.3 reactor since around 8:30 a.m., according to Edano.”
Source: Kyodo News