Images captured by a robotic probe inside one of the three melted reactors
at Japan’s wrecked Fukushima nuclear power plant showed exposed steel bars
in the main supporting structure and parts of its thick external concrete
wall missing, triggering concerns about its earthquake resistance in case
of another major disaster.

The plant’s operator, Tokyo Electric Power
Company Holdings, has been sending robotic probes inside the Unit 1 primary
containment chamber since last year. The new findings released Tuesday were
from the latest probe conducted at the end of March. An underwater remotely
operated vehicle named ROV-A2 was sent inside the Unit 1 pedestal, a
supporting structure right under the core.

It came back with images seen
for the first time since an earthquake and tsunami crippled the plant 12
years ago. The area inside the pedestal is where traces of the melted fuel
can most likely be found. An approximately…