1,000 millisieverts/hour on the 2nd floor was bad enough. And this was supposed to be the reactor that was well on its way to stable cold shutdown.
From Yomiuri Shinbun and Asahi Shinbun, on 5/15/2011 (in Japanese):
2,000 millisieverts, or 2 sieverts, per hour radiation was detected inside the southeast double door of the Reactor 1 reactor building. Measurement was done by a remote-controlled robot on May 13. The location is where the pipe is that goes into the Reactor Pressure Vessel (RPV).
3,000 tons of contaminated water probably leaked from the RPV and the Containment Vessel was found in the basement of the reactor building (where the Suppression Chamber is). TEPCO suspects the water is leaking from the seams of the pipes that connects the Containment Vessel body and the torus-shaped Suppression Chamber.
Now, TEPCO's new plan is to circulate the contaminated water in the basement back into the RPV to cool the RPV.
Well, it was all farce, then; that TEPCO installed the air filtering system and claimed that the radioactive materials inside the Reactor 1 reactor building got safe enough (they were saying a few millisieverts to 10s of millisieverts/hour) for the workers to go in and start working.
Unless the "new normal" for Fukushima I Nuke Plant is to count the radiation in sieverts.
The so-called "water entombment" is officially dead now. TEPCO has poured over 10,000 tons of water inside the RPV. Now they say they've found 3,000 tons of it. Where's the rest, 7,000 tons?