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

Monday, March 14, 2011

Fukushima Daiichi No. 2: Newer details

TEPCO reports continue to come in...

-During an earlier event in which water level dropped low at No. 2 plant, a reading of 3130 microsieverts was recorded near the plant No. 1 gate. This is a very good indication to us that there was no water in the reactor core of No. 2 to attenuate radiation. This is twice the amount seen at any other time from any other reactor during this entire accident sequence.

-It appears that fuel rods were uncovered for about 140 minutes, or two hours and twenty minutes. This is almost certain to have caused some fuel damage. Failure of the plant battery support system appears also to have prevented opening of solenoid operated relief valves to reduce plant pressure.

-TEPCO says that the explosion at No. 3 plant has damaged the reactor building wall at No. 2 plant which may allow generated hydrogen to escape before an explosion like those which occurred at Nos. 1 and 3 earlier in the accident sequence. This is by no means certain.

Repeating an earlier assertion or two.. It is my opinion that it is not solid ground to assure that the secondary containments of these plants are not compromised, and in fact it is not certain that the primary coolant systems are not compromised in some way. Lifted and stuck open or leaking by relief valves are not out of the question.


Additional information: TEPCO has told the Japanese Government and the N&ISA that it is assuming serious fuel element failure in Daiichi No. 2 plant based on the very high rad levels noted earlier. 3:06 PM Monday 3/14

Additional information: TEPCO has again, very early Tuesday morning local, recommenced seawater injection into Daiichi No. 2 after a stoppage. 3:35 PM Monday 3/14


  1. Thanks for working so tirelessly to post all this, Will. I've not got the wattage to understand all of it, but I'm reading you off my google reader list regularly.

  2. Thanks a lot for your updates, I appreciate it.

    It seems that more and more radiation values are listed as 'under servey' (sic!). Censorship or real assessment of dubious values?

  3. You're welcome, gentlemen. This kind of event dictates steady, unpanicked, realistic reporting and there is too much hyperbole in the general press... where very technical matters are being judged by professional journalists and not nuclear engineers. If you have any friends who are edgy, pass on a link!