Nuclear Power

04 Mar 2021

NEA Assesses the Cause and Impact of Fukushima Accident

04 Mar 2021  by World Nuclear News   

As work to decommission the damaged Fukushima Daiichi nuclear power plant and revitalise the surrounding area continues, there are many ways international communities can learn, assist Japan and support each other, according to a new report from OECD Nuclear Energy Agency. Published today, ahead of the 10th anniversary of the disaster, the report summarises the circumstances of the accident, the current status of the site, and lessons learned. It also considers the challenges that lie ahead and makes policy recommendations.

 Units 1-4 at the Fukushima Daiichi plant, photographed on 15 March 2011 (Image; Tepco)

The NEA said the report - Fukushima Daiichi Nuclear Power Plant Accident, Ten Years On: Progress, Lessons and Challenges - is intended to assist Japan's recovery from the accident "for a better future for all, and more generally enhance the safe use of nuclear energy worldwide".

It notes that post-accident analyses have verified that radiation from the accident has not led to any direct impact on human health. However, the health and well-being of more than 150,000 residents in surrounding areas was affected to different degrees (including some early deaths) as a result of evacuations from the area owing both to the tsunami and the nuclear accident, lack of access to health care or medicines, stress-related problems, and other causes. The accident also caused disturbance to the daily life of many people and businesses and other activities.

The report finds that significant progress has been achieved by Japan in "vigorously addressing the accident through actions and reforms at both the technical and institutional levels".

In the immediate aftermath and during the 10 years since the 11 March 2011 disaster, Japanese authorities have undertaken "very challenging" work to address the on-site and off-site consequences, and rebuild the social and economic fabric of the areas impacted by the earthquake and resulting tsunami, and the nuclear accident, the NEA said.

"The decommissioning effort is being pursued with vigour in a structured manner with a focus on risk reduction and with a priority to ensure the safety of workers, the public and the environment."

Environmental remediation is being performed to allow, wherever possible, the safe return of residents to affected off-site areas. Decontamination of the Special Decontamination Area was performed as planned by the end of March 2017, and work in the Intensive Contamination Survey Area was completed in March 2018.

"Most evacuation orders have been lifted and public services have been restored in many of the affected areas," the NEA notes. "There is now a need to enhance the ongoing programme to rebuild and revitalise communities and local economies. This is a significant challenge that is situated more largely in the realm of communications and confidence-building than in that of radiological protection and nuclear safety."

Challenges ahead

Speaking in a webinar today to launch the report, Hajimu Yamana, president of Japan's Nuclear Damage Compensation and Decommissioning Facilitation Corporation, said: "The Fukushima Daiichi nuclear power plant is now managed in a quite stable state and the necessary decommissioning works are progressing smoothly." He added that the area covered by the evacuation order had been decreased to one-fifth of the original area.

However, the NEA noted "significant issues" remain to be faced as Japan continues the clean up the Fukushima Daiichi site and the revitalisation of the surrounding communities. Among the technical challenges are: fuel debris removal; decontamination methods; environmental remediation; and related waste issues. Regulatory and legal challenges include: regulation under uncertainty; reinforcing institutional nuclear safety systems; legal preparedness; holistic optimisation decisions; and effective regulatory engagement with a broad range of stakeholders, including licensees and the public.

The report makes recommendations in nine areas: effective and balanced regulatory transparency, openness and independence; a systematic and holistic approaches to safety; participation in international development of decommissioning technologies; well-planned waste management and disposal; improvements to damage compensation practices; stakeholder involvement and risk communication; recognition of mental health impacts in protective action and recovery; opportunities for economic redevelopment; and, knowledge management.

"These key areas highlight the many opportunities for Japan to provide important and needed leadership on the international level," the NEA said.

Global impact of accident

The report says the Fukushima Daiichi accident has "affected nuclear energy strategy in different countries and regions in different ways and to different extents". The accident, it said, highlighted the strong importance of human behaviour and organisational background for nuclear safety. "The political, economic and social issues, including future energy supplies, global climate change, costs of alternatives and security of energy supply, have varied across regions and countries," the NEA said.

"The main learning from the accident in terms of safety is the need for more resilience for both facilities and organisations," said Olivier Gupta, director general of France's nuclear safety authority and chair of the Western European Nuclear Regulators Association.

The NEA said the Fukushima Daiichi accident was a "watershed moment" for the world that spurred greater exchange of information and best practices between nuclear regulators, the industry and international organisations. Globally, lessons learned have been applied to further enhance the safety of nuclear facilities, particularly in ensuring the availability of robust and diverse systems to respond to accidents and extreme events.

"The global community has come together with Japan both to offer assistance and draw lessons to further improve nuclear safety worldwide," the NEA said. "A common understanding of the accident has led to improved tools to support decommissioning and a better quantification and understanding of plant safety margins."

The Fukushima Daiichi accident has also contributed to a massive global surge in recent years in the development of new nuclear power technologies, including small modular reactors and Generation IV reactors with passive safety features.

"Over the past 10 years, there has been tremendous improvement in the resilience of nuclear plants; however, more in-depth activities remain to be done - particularly in the human aspects of nuclear safety," the NEA said. "Nuclear power is likely to play an important role in addressing the world's energy future, particularly as more countries take serious action to dramatically reduce emissions of carbon into the atmosphere. Hence, ensuring that the lessons are embedded in future policies and practices is vital."

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