28 Jul (NucNet): The overarching lesson learned from the 2011 Fukushima-Daiichi nuclear accident in Japan is that nuclear plant licensees and their regulators must seek out and act on new information about hazards with the potential to affect the safety of nuclear stations, a report by the US National Academy of Sciences concludes.
The report, mandated by congress, says the nuclear industry and organisations with emergency management responsibilities should “assess their preparedness” for severe nuclear accidents associated with offsite regional-scale disasters.
Emergency response plans, including plans for communicating with affected populations, should be revised or supplemented to ensure that there are “scalable and effective strategies, well-trained personnel, and adequate resources for responding to long-duration accident/disaster scenarios”, the report says.
The committee that wrote the report examined the causes of the accident and identified findings and recommendations for improving nuclear plant safety and offsite emergency responses to nuclear plant accidents in the US.
The report says the accident at Fukushima-Daiichi was initiated by the Great East Japan Earthquake and tsunami. 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.
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. But the report says 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.
The report is online (http://www.nasonline.org).
