Posted on 03/15/2011 7:32:54 AM PDT by SeekAndFind
IAEA has been informed by Japanese authorities that a fire in the reactor building of unit 4 could no longer be observed as of 21:15 UTC 15 Mar 2011. The fire was visually observed at the reactor at 20:45 UTC 15 March 2011. The fire had previously been confirmed extinguished at 0200 15 Mar 2011 after burning for two hours.
12:00 UTC 15 Mar 2011: the water level in unit 5 was detected at 201 cm above the top of the fuel (16.6% decrease of immersion level over the previous 5 hours). Officials at the plant exoressed their intent to use an operational diesel generator in unit 6 to supply water to unit 5.
Japanese authorities have reported concerns about the condition of the spent nuclear fuel pool at Fukushima Daiichi Unit 3 and Unit 4. Japanese Defense Minister Toshimi Kitazawa announced Wednesday that Special Defence Forces helicopters planned to drop water onto Unit 3, and officials are also preparing to spray water into Unit 4 from ground positions, and possibly later into Unit 3. Some debris on the ground from the 14 March explosion at Unit 3 may need to be removed before the spraying can begin.
According to IAEA experts, a typical spent fuel pool temperature is kept below 25o C under normal operating conditions. The temperature of a spent fuel pool is maintained by constant cooling. There is suspicion that either power to the spent fuel pool cooling subsystem has not been constant per putative design requirements, or has been compromised in some manner.
Spent fuel assemblies generate intense heat and radiation. Therefore the spent fuel pools must be constantly checked for water level and temperature. If fuel is no longer covered by water or temperatures reach a boiling point, fuel can become exposed and create a risk of radioactive release.
The IAEA can confirm the following information regarding the temperatures of the spent nuclear fuel pools at Units 4, 5 and 6 at Fukushima Daiichi nuclear power plant:
The IAEA can confirm the following information about human injuries or contamination at the Fukushima Daiichi nuclear power plant
DISCLAIMER: the information provided is a snapshot of the latest information made available to the IAEA by Japanese authorities (and is valid at the time-date stamp indicated). Given the fluid situation at the plant, this information is subject to change [at the drop of a hat, for any reason, no reason, for better or worse, concerning either sickness or health (or both), for ever and ever, Amen].
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