Japan nuclear update 16 March 2011
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Japan Earthquake Update (16 March 2011, 03:55 UTC)Japanese authorities have informed the IAEA that a fire in the reactor building of unit 4 of the Fukushima Daiichi nuclear power plant was visually observed at 20:45 UTC of 15 March. As of 21:15 UTC of the same day, the fire could no longer be observed. Fire of 14 March As previously reported, at 23:54 UTC of 14 March a fire had occurred at unit 4.
The fire lasted around two hours and was confirmed to be extinguished at 02:00 UTC of 15 March. Water level in unit 5
Japanese authorities have also informed the IAEA that at 12:00 UTC of 15 March the water level in unit 5 had decreased to 201 cm above the top of the fuel. This was a 40 cm decrease since 07:00 UTC of 15 March. Officials at the plant were planning to use an operational diesel generator in unit 6 to supply water to unit 5.
The IAEA continues to liaise with the Japanese authorities and is monitoring the situation as it evolves.
Japan Earthquake Update (15 March 2011, 22:30 UTC)Japanese authorities have informed the IAEA that the evacuation of the population from the 20-kilometre zone around Fukushima Daiichi has been successfully completed.
The Japanese authorities have also advised that people within a 30-km radius to take cover indoors. Iodine tablets have been distributed to evacuation centres but no decision has yet been taken on their administration.
The IAEA continues to liaise with the Japanese authorities and is monitoring the situation as it evolves.
Japan Earthquake Update (15 March 2011, 20:35 UTC)The Japanese government today requested assistance from the IAEA in the areas of environmental monitoring and the effects of radiation on human health, asking for IAEA teams of experts to be sent to Japan to assist local experts. Preparations for these missions are currently under way.
The missions will draw on IAEA resources and may also possibly involve Response and Assistance Network (RANET) and Member States’ capabilities.
This development follows the IAEA’s offer to Japan of its “Good Offices” – i.e. making available the Agency’s direct support and coordination of international assistance.
RANET is a network of resources made available by IAEA Member States that can be offered in the event of a radiation incident or emergency. Coordination of RANET is done by the IAEA within the framework of the Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency.
The IAEA continues to liaise with the Japanese authorities and is monitoring the situation as it evolves.
Japan Earthquake Update (15 March 2011, 18:00 UTC)The IAEA can confirm the following information about the status of the Fukushima Daiichi nuclear power plant:
Unit 4 was shut down for a routine, planned maintenance outage on 30 November 2010. After the outage, all fuel from the reactor was transferred to the spent fuel pool.
Units 5 and 6 were shut down at the time of the earthquake. Unit 5 was shut down as of 3 January 2011. Unit 6 was shut down as of 14 August 2010. Both reactors are currently loaded with fuel.
As of 00:16 UTC on 15 March, plant operators were considering the removal of panels from Units 5 and 6 reactor buildings to prevent a possible build-up of hydrogen in the future. It was a build-up of hydrogen at Units 1, 2 and 3 that led to explosions at the Daiichi facilities in recent days.
The IAEA continues to monitor and seek information on the status of plant workers, reactor conditions, and spent nuclear fuel at the Fukushima Daiichi nuclear plant.
Japan Earthquake Update (15 March 2011, 15:30 UTC)An earthquake of 6.1 magnitude was reported today at 13:31 UTC in Eastern Honshu, Japan. The Hamaoka nuclear power plant is sited an estimated 100 kilometres from the epicentre.
IEC confirmed with Japan that the plant continues to operate safely.
Units 1 and 2 are decommissioned, Unit 3 is under inspection and not operational, and Units 4 and 5 remain in safe operational status after the earthquake.
Japan Earthquake Update (15 March 2011, 14:10 UTC)The IAEA Incident and Emergency Centre (IEC) continues to monitor the status of the nuclear power plants in Japan that were affected by the devastating earthquake and consequent tsunami.
All units at the Fukushima Daini, Onagawa, and Tokai nuclear power plants are in a safe and stable condition (i.e. cold shutdown).
The IAEA remains concerned over the status of the Fukushima Daiichi nuclear power plant, where sea water injections to cool the reactors in Units 1, 2 and 3 are continuing. Attempts to return power to the entire Daiichi site are also continuing.
After explosions at both Units 1 and 3, the primary containment vessels of both Units are reported to be intact. However, the explosion that occurred at 21:14 UTC on 14 March at the Fukushima Daiichi Unit 2 may have affected the integrity of its primary containment vessel. All three explosions were due to an accumulation of hydrogen gas.
A fire at Unit 4 occurred on 14 March 23:54 UTC and lasted two hours. The IAEA is seeking clarification on the nature and consequences of the fire.
The IAEA continues to seek details about the status of all workers, reactors and spent fuel at the Fukushima Daiichi plant.
An evacuation of the population from the 20-kilometre zone around Fukushima Daiichi is in effect. The Japanese have advised that people within a 30-km radius shall take shelter indoors. Iodine tablets have been distributed to evacuation centres but no decision has yet been taken on their administration.
A 30-kilometre no-fly zone has been established around the Daiichi plant. Normal civil aviation beyond this zone remains uninterrupted. The Japan Coast Guard established evacuation warnings within 10 kilometres of Fukushima Daiichi and 3 kilometres of Fukushima Daini.
The IAEA and several other UN organizations held a meeting at 11:00 UTC today to discuss recent developments and coordinate activities related to consequences of the earthquake and tsunami. The meeting was called under the framework of the Joint Radiation Emergency Management Plan of the International Organizations, and this group expects to work closely together in the days ahead.
IAEA Director General’s Briefing on Day 5 of Japanese Earthquake Emergency (15 March 2011, 14:00 UTC)IAEA Director General Yukiya Amano briefed both Member States and the media on developments at the Fukushima Daiichi nuclear power plant.
Japan Earthquake Update (15 March 2011, 11:25 UTC)Fukushima Daiichi Nuclear Power Plant UpdateRadiation Dose Rates Observed at Site
The Japanese authorities have informed the IAEA that the following radiation dose rates have been observed on site at the main gate of the Fukushima Daiichi Nuclear Power Plant.
At 00:00 UTC on 15 March a dose rate of 11.9 millisieverts (mSv) per hour was observed. Six hours later, at 06:00 UTC on 15 March a dose rate of 0.6 millisieverts (mSv) per hour was observed.
These observations indicate that the level of radioactivity has been decreasing at the site.
As reported earlier, a 400 millisieverts (mSv) per hour radiation dose observed at Fukushima Daiichi occurred between Units 3 and 4. This is a high dose-level value, but it is a local value at a single location and at a certain point in time. The IAEA continues to confirm the evolution and value of this dose rate. It should be noted that because of this detected value, non-indispensible staff was evacuated from the plant, in line with the Emergency Response Plan, and that the population around the plant is already evacuated.
About 150 persons from populations around the Daiichi site have received monitoring for radiation levels. The results of measurements on some of these people have been reported and measures to decontaminate 23 of them have been taken. The IAEA will continue to monitor these developments.
Evacuation of the population from the 20 kilometre zone is continuing.
The Japanese have asked that residents out to a 30 km radius to take shelter indoors. Japanese authorities have distributed iodine tablets to the evacuation centres but no decision has yet been taken on their administration.
Background on Radiation
A person’s radiation exposure due to all natural sources amounts on average to about 2.4 millisievert (mSv) per year. A sievert (Sv) is a unit of effective dose of radiation. Depending on geographical location, this figure can vary by several hundred percent.
Since one sievert is a large quantity, radiation doses are typically expressed in millisievert (mSv) or microsievert (µSv), which is one-thousandth or one millionth of a sievert. For example, one chest X-ray will give about 0.2 mSv of radiation dose.
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