Nuclear safetyU.S. nuclear plant licensees should seek, act on nuclear plant hazards information

A new congressionally mandated report from the National Academy of Sciences concludes that the overarching lesson learned from the 2011 Fukushima Daiichi nuclear accident is that nuclear plant licensees and their regulators must actively seek out and act on new information about hazards with the potential to affect the safety of nuclear plants. 

The committee that wrote the report examined the causes of the Japan accident and identified findings and recommendations for improving nuclear plant safety and offsite emergency responses to nuclear plant accidents in the United States.

The accident at the Fukushima Daiichi plant was initiated by the Great East Japan Earthquake and tsunami on 11 March 2011. The earthquake knocked out offsite AC power to the plant, and the tsunami inundated portions of the plant site. Flooding of critical equipment resulted in the extended loss of onsite power with the consequent loss of reactor monitoring, control, and cooling functions in multiple units. Three reactors — Units 1, 2, and 3 — sustained severe core damage, and three reactor buildings — Units 1, 3, and 4 — were damaged by hydrogen explosions. Offsite releases of radioactive materials contaminated land in Fukushima and several neighboring prefectures, prompting widespread evacuations, distress among the population, large economic losses, and the eventual shutdown of all nuclear power plants in Japan.

A National Research Council (NRC) release reports that personnel at the Fukushima Daiichi plant responded to the accident with courage and resilience, and their actions likely reduced its severity and the magnitude of offsite radioactive material releases, the committee said. However, several factors relating to the management, design, and operation of the plant prevented plant personnel from achieving greater success and contributed to the overall severity of the accident.