> They withstood the earthquake. They were not shut down by the earthquake.

You know nothing about safety of nuclear power plants in Japan?

There is a nuclear power plant. Then there is a strong earthquake.

Technical systems will automatically shutdown the powerplant, if the earthquake is of a certain strengths. If not, it might be shutdown because of other factors (like loss of outside electricity).

Then one does not know the state of the power plant.

Then an inspection will determine the state of the powerplant. It might also be the case that damage was minor. Still the question again: is this powerplant still safe to operate? Will it survive another earthquake? Are the assumptions about the strength of earthquake still correct etc.

It will be determined if powerplants will need technical improvements, for example powerplants on the coast might need better flood protections. It is then seen if technical improvements are possible & economical.

Take for example Fukushima Daini, another nuclear powerplant on the coast:

https://en.wikipedia.org/wiki/Fukushima_Daini_Nuclear_Power_...

To make it clear to you: Daini is ANOTHER power plant and not the Daiichi powerplant. It also sits on the coast and it has four reactors. A single powerplant with four reactors, on the coast. Affected by both the Earthquake and the Tsunami (which was caused by the Earthquake).

"All four units were automatically shut down (scram) immediately after the earthquake"

"The tsunami caused the plant's seawater pumps, used to cool reactors, to fail. Of the plant's four reactors, three were in danger of meltdown.[19] One external high-voltage power line still functioned, allowing plant staff in the central control room to monitor data on internal reactor temperatures and water levels. 2,000 employees of the plant worked to stabilize the reactors. Some employees connected over 9 kilometers of cabling using 200-meter sections of cable, each weighing more than a ton, from their Rad Waste Building to other locations onsite."

"The tsunami that followed the earthquake and inundated the plant was initially estimated by TEPCO to be 14 meters high, which would have been more than twice the designed height.[11] Other sources give the tsunami height at Fukushima Daini plant at 9-meter-high"

"In unit 3, one seawater pump remained operational and the residual heat removal system (RHR) was started to cool the suppression pool and later brought the reactor to cold shutdown on March 12."

"The loss of cooling water at reactors 1, 2 and 4 was classified a level 3 on the International Nuclear Event Scale (serious incident) by Japanese authorities as of March 18."

"As of June 2011, 7,000 tons of seawater from the tsunami remained in the plant. The plant planned to release it all back into the ocean, as the tanks and structures holding the water were beginning to corrode. Approximately 3,000 tons of the water was found to contain radioactive substances, and Japan's Fisheries Agency refused permission to release that water back into the ocean."

and so on.

The reactor was early on in a critical state and three more meltdowns were feared.

You did not do any research on what happened with the reactors in Japan.

Sad.

They had a lot of luck that this powerplant did not have the same fate as the one in Fukushima Daiichi.

TEPCO has closed the plant and it will be decommissioned.

The Japanese nuclear industry was prone to corruption, incompetence and criminal behavior. Especially TEPCO the owner of the plants:

https://www.spiegel.de/international/world/fumbling-toward-f...

"On March 2, 2011, just days before the start of the current earthquake catastrophe, Japan's nuclear regulators lobbed accusations of mass negligence against Tepco. It alleged that Tepco had failed to inspect 33 pieces of equipment at the Fukushima-Daiichi plant, one of the sites of the current catastrophe, including central cooling system elements in the six reactors, and spent fuel pools that hadn't been inspected according to regulations. The company has since admitted to having made the errors."

"At the same time, Tepco also reported to the nuclear regulatory authority that it had not only failed to do the 33 inspections at the Fukushima-Daiichi plant, but also 19 further inspections at the nearby Fukushima-Daini plant."

Just shortly before the Earthquake, the reactors were claimed to be safe by Tepco.