Japan did not do enough to protect the Fukushima Dai-ichi nuclear power plant, which was severely damaged by a giant wall of water in March 2011, despite authorities being aware of threats to the facility from earthquakes and tsunamis, the International Atomic Energy Agency (IAEA) stated in a report. The U.N. nuclear watchdog also criticized Tokyo Electric Power Co (TEPCO), the plant's operator, for not acting on the warnings.

The IAEA said, in its final report on the March 2011 disaster, which was the result of a massive earthquake and subsequent tsunami, that a new method applied between 2007 and 2009 had predicted a magnitude-8.3 quake off the coast of Fukushima that could lead to a tsunami hitting the facility. On March 11, 2011, a magnitude-9 earthquake struck off Japan's northeastern coast, triggering a massive tsunami that ultimately cost the Japanese government about $300 billion in damages.

“The Fukushima Daiichi NPP (nuclear power plant) had some weaknesses which were not fully evaluated by a probabilistic safety assessment, as recommended by the IAEA safety standards,” the report obtained by Kyodo News, a Japanese news agency, stated.

TEPCO did not take the necessary precautions despite the analysis, the IAEA report, which is expected to act as a reference for nuclear safety measures worldwide, reportedly stated. The incident was the world's worst nuclear disaster since the 1986 Chernobyl nuclear disaster in Ukraine.

“TEPCO did not take interim compensatory measures in response to these increased estimates of tsunami height, nor did NISA require TEPCO to act promptly on these results,” the report said, according to the Japan Times. “Prior to the accident, there was not sufficient consideration of low probability, high consequence external events which remained undetected. This was in part because of the basic assumption in Japan, reinforced over many decades, that the robustness of the technical design of the nuclear plants would provide sufficient protection against postulated risks.”

TEPCO also failed to implement sufficient safety assessment measures as recommended by the IAEA and lacked protection against tsunami-caused flooding, Kyodo News reportedly said, citing the IAEA report.

“The operators were not fully prepared for the multiunit loss of power and the loss of cooling caused by the tsunami. Although TEPCO had developed severe accident management guidelines, they did not cover such an unlikely combination of events,” the report stated.