(UPDATE) I just had a laugh for the night. In TEPCO's press conference on December 12, TEPCO has just said this robot has crashed. TEPCO was going to check one or two more vent pipes on December 12, but the robot lost its balance and collapsed on the staircase to the torus room and cannot move. TEPCO will investigate the cause of this malfunction tomorrow.
In the demonstration in Yokohama in November, humans had to carry the robot off the stairs when it froze. I suppose Toshiba workers will have to retrieve the robot from the torus room, braving the high radiation.
It was very stupid to send the clumsy robot like this on a task similar to the one that had caused it to freeze in the demonstration. TEPCO that cannot say no (or doesn't say no).
In the video released by TEPCO on December 11, the Toshiba robot who froze with one leg up in the air during the demonstration in November in Yokohama takes time to put one leg forward and then another. It takes about 25 seconds for it to lift the left hind leg and put it on the next step.
I feel sorry for TEPCO for having to accept a dud like this.
The video title is "Investigation on the lower part of Unit 2 vent pipe at Fukushima Daiichi Nuclear Power Station (Mockup test)", indicating TEPCO is going to use this thing in Reactor 2.
(Video is being uploaded right now.)
And it did. TEPCO just released the photos of the vent pipe that was examined by the robot on December 11. There is no discernible leak or damage to this particular pipe.
From TEPCO's handout for the press, "Results of Investigation on the Lower Part of Unit 2 Vent Pipe at Fukushima Daiichi Nuclear Power Station" (12/11/2012), page 2 (click to enlarge):
No information on how long it took this robot to do the work. Page 3 says actual radiation dose was 1.75 millisievert, but no information whether that was for the robot or the robot operator(s).
Edge of vent pipe sleeve:
Edge of sand cushion drain pipe:
Lower part of vent pipe bellows cover:
On March 15, 2011, a loud sound was heard from the Reactor 2 torus room, and Reactor 2 is supposed to have released radioactive material an order of magnitude larger than the other reactors.