from little they saw.
6 TEPCO workers entered the basements (mezzanine floor) of Reactors 2 and 3 buildings on March 14 to try to survey the damage in the Suppression Chambers. Max radiation exposure for the workers was 2.87 millisieverts. Expected dose was 10 millisieverts, but they seem to have gotten out of Reactor 3 rather quickly, spending only 8 minutes there as opposed to 20 minutes in Reactor 2.
From what Yomiuri reported (3/14/2012), about Reactor 2's basement:
No apparent damage as far as the workers could see;
Photos of the Suppression Chamber taken from a small adjacent room (window);
Radiation levels in the adjacent rooms were 20 to 35 millisieverts/hour;
Radiation levels near the Suppression Chamber were 130 to 160 millisieverts/hour;
Water in the 1st floor of the basement;
TEPCO will use robots for further survey, as the radiation levels [in the Suppression Chamber] were too high for humans.
Well wasn't that rather obvious that the radiation levels would be rather high? Why didn't TEPCO use Quince or Packbot? (TEPCO needs those swarming flying robots.)
Looking at the photos released by TEPCO, Reactor 2 Suppression Chamber looks more or less undamaged. The workers were supposed to take temperature and humidity measurements as well as radiation levels, but no information released regarding temperature and humidity.
Looking at the photos of Reactor 3 basement, they look highly humid. The workers apparently didn't, or couldn't measure the radiation levels at the door of the Suppression Chamber, like they did in Reactor 2.
From TEPCO's handout for the press in English (3/14/2012):
(Note: Date is wrong. It was March 14. The timeline is wrong. They entered Reactor 3 at 12:40 and exited from Reactor 3 at 12:48.)
If the Suppression Chamber of Reactor 2 is not broken, where did all the radioactive materials from Reactor 2 come from?