Conditions inside Fukushima's melted nuclear reactors still unclear 13 years after disaster struck

abcnews.go.com:

Japan is marking 13 years since a massive earthquake and tsunami hit the country’s northern coasts, killing nearly 20,000 people, wiping out whole towns and destroying the Fukushima Daiichi nuclear power plant

TOKYO — Japan on Monday marked 13 years since a massive earthquake and tsunami hit the country’s northern coasts. Nearly 20,000 people died, whole towns were wiped out and the Fukushima Daiichi nuclear power plant was destroyed, creating deep fears of radiation that linger today. As the nation observes the anniversary, the AP explains what is happening now at the plant and in neighboring areas.

A magnitude 9.0 earthquake struck on March 11, 2011, causing a tsunami that battered northern coastal towns in Iwate, Miyagi and Fukushima prefectures. The tsunami, which topped 15 meters (50 feet) in some areas, slammed into the nuclear plant, destroying its power supply and fuel cooling systems, and causing meltdowns at reactors No. 1, 2 and 3.

Hydrogen explosions caused massive radiation leaks and contamination in the area.

The operator, Tokyo Electric Power Company Holdings, says that the tsunami couldn’t have been anticipated. Government and independent investigations and some court decisions have said the accident was the result of human error, safety negligence, lax oversight by regulators and collusion.

Japan has since introduced stricter safety standards and at one point shifted to a nuclear energy phaseout. Prime Minister Fumio Kishida’s government reversed that policy and has accelerated restarts of workable reactors to maintain nuclear power as a main source of Japan’s power supply.

A deadly Jan. 1 earthquake in Japan's northcentral region destroyed many homes and roads but didn't damage an idled nuclear power