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Wednesday, April 27, 2011

Fukushima Nuclear Accident Update Log - Updates of 26 April 2011

The latest update from IAEA with regards to the situation in Fukushima, Japan, excerpt :

" IAEA Briefing on Fukushima Nuclear Accident (26 April 2011, 18:00 UTC)

1. Current situation

Overall, the situation at the Fukushima Daiichi nuclear power plant remains very serious, but there are signs of recovery in some functions, such as electrical power and instrumentation.

After the announcement on 11 April by the Government of Japan to establish 'planned evacuation zones' and 'emergency evacuation preparation zones', in a press conference on 22 April by the chief cabinet secretary of Japan Mr. Edano it was stated that "the Prime Minister, as head of the Nuclear Emergency Response Headquarters, has issued instructions to the governor of Fukushima Prefecture and the heads of municipal governments concerned." These instructions included:

Designation of 'planned evacuation zones' to be applied to some specific zones outside the 20 km radius from the Fukushima Dai-ichi plant: "the villages of Katsurao, Namie and Iitate, part of the town of Kawamata, and part of the city of Minamisoma", where planned evacuations are expected to be implemented in approximately one month's time.

Designation of 'emergency evacuation preparation zones', to be applied to the area within a 20-30 km radius from the Fukushima Dai-ichi plant (except for areas designated as planned evacuation zones): "the towns of Hirono and Naraha, the village of Kawauchi, and parts of the cities of Tamura and Minamisoma", in which preparations should be made so that the residents can take shelter indoors or can evacuate by their own means in the event of an emergency. In addition, with regard to the areas located within a 20-30 km radius from the nuclear power plant, the advisory for sheltering indoors that has been in effect to date has been lifted.

Changes to Fukushima Daiichi plant status


The IAEA receives information from various official sources in Japan through the Japanese national competent authority, the Nuclear and Industrial Safety Agency (NISA). Additional detail is provided in the IAEA Incident and Emergency Centre (IEC) status summary with information received by 07:00 UTC on 26 April 2011.

Management of on-site contaminated water

According to the 25 April evaluation by NISA of the report submitted by TEPCO, there is a little less than 70,000 tonnes of stagnant water with high level radioactivity in the basement of the turbine buildings of Units 1, 2 and 3.

Plant status

On 25 April the power supply for the temporary electrical pumps that supply water to the reactor pressure vessel of Units 1, 2 and 3 was switched from the off-site power supply to temporary diesel generators to allow work to enhance the off-site supply.

White smoke continues to be emitted from Units 2, 3 and 4.

In Unit 1 fresh water is being continuously injected into the reactor pressure vessel through the feedwater line at an indicated flow rate of 6 m3/h using a temporary electric pump with off-site power.

In Unit 2 and Unit 3 fresh water is being continuously injected into the reactor pressure vessel through the fire extinguisher line at an indicated rate of 7 m3/h using temporary electric pumps with off-site power.

In Unit 4 140 tonnes of fresh water was sprayed over the spent fuel pool on 23 April and 165 tonnes of fresh water was sprayed over the spent fuel pool on 24 April using a concrete pump truck. The nuclear emergency response headquarters reported that temperature measurements showed the spent fuel pool temperature to be 83 °C before spraying and 66 °C after spraying on 23 April, and the spent fuel pool temperature to be 86 °C before spraying and 81 °C after spraying on 24 April."

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