APR: your source for nuclear news and analysis since April 16, 2010

Friday, March 25, 2011

JAIF status update, and other new information

Further evidence that the SBO or Station Blackout accident sequence experienced by Fukushima Daiichi No. 1, No. 2 and No. 3 plants may have led, as predicted, to both serious core damage (which is certain) and either pressure vessel failure (perhaps in the location of a lower head penetration, if not one of the other failure modes) or else containment structure failure is out today. Apparently now all three plants have very highly radioactively contaminated water in their turbine buildings.

The latest JAIF status report reflects unknown pressure vessel status for all three plants, which is a change for No. 3 plant. No. 3, in previous documents had been listed as "damage suspected." This may be an upgrade if JAIF, NISA and TEPCO think that the coolant in the reactor buildings isn't due to primary system failure.

In addition, at 11:00 AM Tokyo time the instruction was given to change water injection to the cores of No. 1 and No. 3 plants from salt water to fresh water as fears of corrosion and deposition of salt, as well as troubles with sediment in the seawater, lead to suspicion that the procedure (an emergency stop gap when there is no other water available and core melt must be prevented or contained) is now doing as much harm as good and is about to change the other way to more harm than good. This occurred on No. 1 plant at 3:37 PM and on 6:02 PM on No. 3 plant. (This data directly from TEPCO.)

Here is the most recent JAIF status report:


Other data indicates that the temperature disparity on the No. 3 plant RPV is likely due to instrument failure since last reading of feed nozzle temp was about 33 degrees Celsius below zero.

There is sure to be much more data as the day comes alive in Japan, and we'll be here to report on it.

3:30 PM Eastern Friday 3/25

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