Latest from Fukushima
Mainichi, Mar 28, 2017 (emphasis added): [TEPCO] failed to locate melted nuclear fuel inside the No. 1 reactor at the disaster-stricken Fukushima No. 1 Nuclear Power Plant… [T]he latest survey on the No. 1 reactor also failed to obtain data necessary to extract melted fuel, such as where the fuel is located. Therefore, the utility is compelled to consider fetching melted fuel in the absence of sufficient data… [T]he robot explored an area around the opening for workers at the bottom of the container vessel… It is believed that most of the melted fuel at the No. 1 reactor has spread across the contaminated water accumulating at the bottom of its container vessel. TEPCO believes that melted fuel is likely leaking from the opening.
Asahi Shimbun, Mar 24, 2017: Some Nuclear Regulation Authority members are skeptical of continuing to send robots into reactors in the crippled Fukushima No. 1 nuclear plant… These regulators are increasingly calling for a new survey methodology after recent investigations utilizing robots controlled remotely generated few findings and were quickly terminated… The lower part of the reactor’s containment vessel is submerged in water where deposits of fuel debris are believed to reside below the surface after melting through… TEPCO and the government… have yet to collect information on the location, amount and condition of the melted fuel… [T]he surveys centering around the robots so far have failed to produce meaningful results.
Asia Times, Mar 10, 2017: The robots are part of an unprecedented task, challenging engineers to come up with technology that doesn’t exist to deal with a nuclear disaster the likes of which has never been known.
See also: Nuclear Investigator: Worry over underground explosions at Fukushima — New data shows molten fuel is “dropping lower each day”, melting deeper into ground below plant
Source: Officials: Melted fuel still leaking out of Fukushima reactor — Likely escaping from opening at bottom of containment vessel — Gov’t experts want to give up sending in robots to search for molten cores — “Disaster the likes of which has never been known” « ENENews.com – Energy News