The Nuclear Regulation Authority decided Wednesday to resume a probe into the causes of meltdowns in 2011 at the Fukushima No. 1 power plant, having determined that radiation levels have fallen enough to allow investigators to access the site.
The nation’s nuclear watchdog will seek to determine whether one of the reactors failed to properly vent radioactive steam, among other questions. It expects to report its findings before the end of next year.
An interim report released in October 2014, based on investigations conducted from 2013, attributed the meltdowns of three reactors at the coastal plant to a tsunami that caused a catastrophic power loss, leading to the failure of the plant’s cooling system.
The probe was suspended after it was deemed unsafe to enter some buildings at the plant, which is operated by Tokyo Electric Power Company Holdings Inc.
The NRA will work with the Natural Resources and Energy Agency, which instructs Tepco on its decommissioning efforts, to ensure that facilities at the plant relevant to the investigation are preserved.