In March 1997 a fire broke out in the bituminisation facility where spent fuel is encased in molten asphalt (bitumen) for storage.

[5] In 2002, an evaluation technology adopted by the Japan Society of Civil Engineers had determined that the site of the plant could experience tsunami waves as high as 4.86 metres.

Additions to the seawall that raised it to a height of 6.1 meters were completed on 9 March, just two days before the 2011 Tōhoku earthquake and tsunami.

[11] Construction work on additional safety measures, including a 1.7 km sea wall to protect from possible tsunamis, was originally scheduled to be completed in March 2021.

[13] Seismic research in 2011 showed that the March 11th quake was caused by the simultaneous movement by multiple active faults off the coast of northern Japan in the Pacific Ocean, and in this way a much bigger earthquakes could be triggered, than the plants were designed to withstand at the time they were built.

[16] In March 2021, the Mito District Court ordered the Tokai 2 reactor suspend operations, following the request of 224 plaintiffs.

The plaintiffs, residents of Ibaraki Prefecture and the Tokyo metropolitan area, filed a lawsuit in 2012 against the operator.

One of the key contentions was the appropriateness of the Japan Atomic Power's seismic ground motion figure.

[17] On 11 October 2011 Tatsuya Murakami, the mayor of the village Tokai, said in a meeting with minister Goshi Hosono, that the Tokai 2 reactor situated 110 kilometers from Tokyo should be decommissioned, because the reactor was more than 30 years old, and the people had lost confidence in the nuclear safety commission of the government.

[18] In 2011 and 2012, about 100,000 signatures against the resumption of the plant's operation which shutdown due to the 2011 earthquake, were submitted to Ibaraki Governor Masaru Hashimoto.