A new report from the OECD Nuclear Energy Agency on the response and lessons learned from the Fukushima Daiichi accident says that it is the ‘collective responsibility’ of the nuclear community to ensure that there is no complacency in the implementation of nuclear safety practices and concepts.

"Nuclear safety professionals have a responsibility to hold each other accountable to effectively implement nuclear safety practices and concepts," the report states. It also calls for a ‘consistent international effort’ to gain in-depth feedback from the accident over the next decade.

The Fukushima Daiichi Nuclear Power Plant Accident: OECD/NEA Nuclear Safety Response and Lessons Learnt was published 10 Septemper, two and a half years after the March 2011 accident at Fukushima Daiichi in Japan. It outlines the international efforts that have been taken to strengthen nuclear regulation, safety, research and radiological protection in the post-Fukushima context. It also looks at lessons learned in the areas of safety assurance, shared responsibilities, human and organizational factors, defence-in-depth, stakeholder engagement, crisis communication and emergency preparedness.

Actions taken by NEA member countries include comprehensive safety assessments at nuclear facilities – also known as the stress tests. These assessments found that facilities offered a sufficient level of safety and that no immediate shutdown was required, the report states.

However it said that continued operation of nuclear power plants requires that their robustness to extreme situations be increased beyond the existing safety margins "as soon as possible." It also said that it is "crucial to continue these reassessments on a periodic basis and to ensure that all safety improvements identified are fully implemented in a timely manner."

The report found that the fundamental principles of nuclear safety remain valid, but did find some areas where additional guidance could be useful.

"Although the principles upon which nuclear safety has been built remain valid, notably the defence-in-depth concept, more needs to be done to ensure their effective implementation in all countries and all circumstances," said NEA Director-General Luis Echávarri.

The report identifies that there would be benefit from having guidance from regulatory authorities in each country on the application of DiD in such areas as: prevention and mitigation at each level of DiD; to ensure that actions taken and resources relied upon at one level of DiD can be made independent from the other levels; and to minimise the potential for common-cause failures propagating from one level to another.

The report also said that a questioning and learning attitude is "essential" to continue improving the high level of safety standards and their effective implementation.

It said that since a severe accident can never be completely ruled out, the necessary provisions for dealing with and managing a radiological emergency situation, onsite and offsite, must be "planned, tested and regularly reviewed." The report also emphasized the importance of crisis communication, co-ordination and consistency in national and international responses to emergencies.

In-depth investigation from the Fukushima Daiichi accident is expected to continue for the next ten years, or more, the report said. It called for "consistent international effort" and said that in this regard "care must be taken to ensure that all international initiatives remain consistent and avoid any duplication of work."

Photo: Fukushima Daiichi unit 3, back in March 2011 (Source: Tepco)