[9] In January 1989, an impeller blade on one of the reactor coolant pumps in Unit 3 broke at a weld, causing a large amount of metal debris to flow throughout the primary loop.

[10] The March 11, 2011 Tōhoku earthquake resulted in maximum horizontal ground accelerations of 0.21 g (2.10 m/s2) to 0.28 (2.77 m/s2) at the plant site, which is well below the design basis.

[14][15][16][17][18] 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.

[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.

The steam-powered reactor core isolation cooling system (RCIC) in all 4 units was activated and ran as needed to maintain water level.

At the same time, operators utilized the safety relief valve systems to keep the reactor pressures from getting too high by dumping the heat to the suppression pools.

[13] 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.

[13] Operators had to also prepare an alternate injection line for each unit, as the RCIC can run indefinitely only while there is sufficient pressure and steam in the reactor to drive its turbine.

[25] 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.

The plant planned to release it all back into the ocean, as the tanks and structures holding the water were beginning to corrode.

[37] In 2015, the evacuation order for Naraha was completely lifted, allowing residents to return and reconstruction efforts to begin.

[41] Chief Cabinet Secretary Yoshihide Suga said that the third reactor's spent fuel pool cooling systems at Fukushima Daini had stopped as a result of the earthquake; TEPCO later reported the restart of the spent fuel cooling system after only 100 minutes of stoppage.

[40][41][42][43] On 31 July 2019, the TEPCO board of directors decided to decommission the plant, in response to local demands for a decision.