NHK World, Feb 3, 2017 (emphasis added): The operator of the crippled Fukushima Daiichi nuclear power plant is examining if it can go ahead with a plan to deploy a robot into one of the damaged reactors at the facility… An analysis of the images found that the radiation level inside the vessel was up to 530 sieverts per hour. Officials speculate that fuel debris–a mixture of nuclear fuel andmelted parts of the reactor’s facility–may be emitting strong radiation
inside the vessel… Last week’s probe found that part of a metal grating just beneath the reactor was missing. The robot was supposed to move around on the grating. The image analysis also found that an around one square-meter section near the missing segment is about to collapse.
NHK World transcript, Feb 3, 2017: “[Tepco] is facing more setbacks. Tepco has found unstable grating near a rector that will make it difficult to conduct further surveillance to help it decommission the plant… They found a section the size of a square meter is about to collapse. They had already found holes in other sections… A nuclear power expert suggests that will make it difficult for workers to locate the fuel.”
NHK World transcript, Feb 3, 2017 (at 1:30 in): “Engineers were able to get a glimpse inside Reactor No. 2… They found that a section one meter square is about to collapse. They had already found holes in other sections.” (Click to Article)