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Friday, March 25, 2011

IAEA : Fukushima Nuclear Accident Update Log

Updates from IAEA, excerpt :

" IAEA Briefing on Fukushima Nuclear Accident (24 March 2011, 21.30 UTC)

On Thursday, 24 March 2011, Graham Andrew, Special Adviser to the IAEA Director General on Scientific and Technical Affairs, briefed Member States on the current status of nuclear safety in Japan. His opening remarks, which he delivered at 15:30 UTC at the IAEA headquarters in Vienna, are provided below:

Current Situation

As far as the reactors at the Fukushima Daiichi site are concerned, there is some good news to report from the last 24 hours, although the overall situation is still very serious.

With AC power connected, instrumentation continues to be recovered in Units 1, 2 and 4. Workers returned after being evacuated from Units 3 and 4 on March 23, following confirmation that black smoke emissions from Unit 3 had ceased.

Reactor pressure is increasing in Unit 1, pressure readings are unreliable in Unit 2, and stable in Unit 3 as water continues to be injected through their feed-water pipes. The temperature at the feed-water nozzle of the Reactor Pressure Vessel (RPV) is decreasing at Units 1 (243 °C) and 3 (about 185 °C), and stable at Unit 2 (about 102 °C).

Units 5 and 6 are still under cold shutdown, they are undergoing maintenance using off-site AC power and existing plant equipment.

Dose rates in the containment vessels and suppression chambers of Units 1 and 2 have decreased slightly.

Radiation Monitoring

The IAEA radiation monitoring team made additional measurements at distances from 21 to 73 km from the Fukushima nuclear power plant. At distances between 34 and 73 km, in a westerly direction from the site, the dose rate ranged from 0.6 to 6.9 microsievert per hour. At the same locations, results of beta-gamma contamination measurements ranged from 0.04 to 0.4 Megabecquerel per square metre.

At distances between 30 and 32 kilometers from the Fukushima Nuclear Power Plant, in a north westerly direction from the site, dose rates between 16 and 59 microsievert per hour were measured. At these locations, the results of beta-gamma contamination measurements ranged from 3.8 to 4.9 Megabecquerel per square metre. At a location of 21 km from the Fukushima site, where a dose rate of 115 microsieverts per hour was measured, the beta-gamma contamination level could not be determined."

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