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

Monday, May 23, 2011

Fukushima Daiichi No. 2 and No. 3

Well, as expected at some point, we now have a statement by TEPCO (right now only seemingly carried by Kyoto News) that the reactor cores in No. 2 and No. 3 plants at Fukushima Daiichi are partially melted down. The story says that this information is "updating its earlier assessment that just the No. 1 reactor suffered critical fuel melting."

That's not true, and Kyoto News should know that. Not only has TEPCO assumed core damage at the plants since very early, this blog and many others have reported it. The JAIF daily status reports have shown probable core damage at all three plants for a long time. We've archived a number of these; the March 14th JAIF status shows core damage at No. 1 and No. 3, with No. 2 listed as "unknown." The March 16th JAIF status update downgrades No. 2 plant to fuel damaged status as well... like the other two.

In other words, considering that the JAIF was getting its information from best-guess estimates from TEPCO, and NISA, there's just no basis at all to make any statement that this is the first affirmation of core damage .. call it 'partial melt' if you like .. for all three plants by any stretch of the imagination. Further, this blog carried many mentions of SBO accident scenario studies indicating serious core damage being highly probable given the circumstances. "Serious core damage" translates along the event line to melt, by the way.

As such, while this "news" story is on the wires and will get legs, no one should be surprised or further alarmed by it.

8:35 PM Eastern Monday 5/23


  1. "TEPCO is expected to submit a report to the Japanese Government today which will apparently assert clearly that there was NO damage to the reactor plants as a result of the Great East Japan Earthquake... The damage sequence began when the tsunami hit and triggered an essentially unrecoverable SBO accident scenario."

    The exasperation and pity is that far too many -- both public worldwide and nuclear industry P.R. -- don't know or get this single way too underplayed critical point for acceptance of nuclear energy.

    James Greenidge

  2. Is there any way they could use ultrasound on the pressure vessel to ascertain the condition of the core?

    James Greenidge

  3. re. "NO damage to the reactor plants as a result of the Great East Japan Earthquake" should be interesting, especially since the emergency cooling in #1 shut down 10 mins after activation, 30 mins before the water came. Do we still need to bother even reading their own assessments?

    By the way, we have confirmed multiple 4-inch holes in containment vessel, at least in #2