Link to Status of Daiichi/Daini as of 1230 Mar 16 provided by JAIF.
New estimates from JAIF regarding situation in graphical/picture form. Still nothing new from NISA, and IAEA and TEPCO's sites are difficult to access.
TEPCO is reporting that they're seeing steam/white smoke rising from around Unit 3, potentially indicating some damage to the containment. Higher radiation levels have been noted at the site but these could be from Unit 2's damage or from the Unit 4 fuel deposit.
There is potential for use of helicopters to drop boric acid onto the pool at Unit 4 to prevent a recriticality casualty from occurring as the radiation levels are too high for humans to approach to investigate or conduct lengthy operation. (That is where the 400 mSv/hr is.)
Preparations are underway to inject water into the refueling pool as they fear that the rods are cooking off the water due to their disarray from the explosions moving them close enough together to restart fission reactions.
The threat of a recriticality casualty from Unit 4's spent fuel is a major concern, as the intense protective barriers that exist for the reactor core do not exist for other areas in the plant. If the spent fuel achieves criticality there will be a much higher release to the environment. It should be noted however that by it's very nature of being spent fuel it will be more difficult for it to achieve and sustain a critical reaction.
Unit 4 itself is okay, and that reactor has been shutdown since November of last year.
Approximately 70 workers of the Daiichi site's 800 remain on site to continue efforts for control.
The second fire seen by workers at the Unit 4 building extinguished itself in a timeframe of about 30 minutes. The fire is believed to be from the same location that a hydrogen explosion occurred earlier in the week, but the radiation levels from the fuel pool have made it difficult/impossible to safely investigate areas around Units 3 and 4.
It is now believed that ~70% of the fuel rods in Unit 1 have sustained damage, and ~33% of the fuel rods in Unit 2 have sustained damage. No reports on Unit 3 or the Unit 4 storage pool.
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