Welcome to European Tribune. It's gone a bit quiet around here these days, but it's still going.
Reading on, I found the following interesting details regarding the No. 2 reactor's accident:

  • Apparently, they think hat the problems started with a water leak from the reactor pressure vessel, which shut down the steam-powered cooling system at 13:25 on 14 March (this system needs battery electricity only to operate valves). However, they say they won't know for certain that the cooling system worked properly even before the shutdown until they don't dismantle it to check its parts.
  • Here we have a data on how long it took to install and activate seawater injection: from 16:34 to 19:54 on 14 March (that's exactly three and a half hours). However, they are still not certain whether seaweater injection worked at all, against the high pressure.
  • In TEPCO's simulation, the fuel was uncovered five hours after the loss of cooling, with core damage from the second hour.
  • I can't make sense of what they say about NISA's cross-check simulation (possibly bad translation): they agree on the fuel uncovering and meltdown timeline, however, conclude that the pressure vessel was damaged five hours after the earthquake (that's 70 hours before the fuel was uncovered!). Regarding material release, NISA estimates gives a wide range: 0.4-7% for iodine, 0.4-3% for tellurium, and 0.3-6% for caesium.
  • There was one venting on 13 March (before the loss of cooling and the now assumed meltdown) and one at the start of 15 March (after the meltdown), both without achieving a reduction of dry well pressure.
  • The fuel conditions are the same as at No. 1: temperature changes indicate that (most of?) it is cooled at the bottom of the pressure vessel with part of it above water, and some may be in the containment vessel.
  • Regarding the suppression chamber explosion, without being able to get there, they still don't know the cause. However, there was associated external damage: to the neighbouring waste processing building.

As for a final conclusion:

At this point, we cannot indentify to what extent each component functioned, and therefore, cannot determine how the events of the accident have developed.

Still in the dark, three months on.

*Lunatic*, n.
One whose delusions are out of fashion.

by DoDo on Mon Jun 13th, 2011 at 07:20:43 AM EST
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