To improve the severe accidents analysis and risk management standards, upgrade the safety regulatory of nuclear power and prevent the incidents caused by extreme natural disasters, the 25^th International Conference on Nuclear Engineering held a forum on Fukushima Issues Lessons learned. The forum was chaired by Professor Yasuo Koizumi from Japan Atomic Energy Agency (JAEA).

JSME Severe Accidents Management: continuously improve the standards and regulations

Mr. Kazuyuki Tsukimori from JAEA introduced the evaluation guideline of development of the containment structure under severe accidents, presented the types and unsuccessful mode of the containment in Japan’s nuclear power plants, and demonstrated the integrity evaluation methodology. He suggested that the pressure and temperature bearing capabilities should be displayed and explained under JSME’s guidelines.

Mr. Koji Shirai from Central Research Institute of Electric Power Industry introduced the frequencies, prevention measures and related updated regulation of tornadoes happened in Japan. JSME completed the drafts in March, 2017 and is planning to publish the contents in March 2018 after voting.

Mr. Masaki Morishita presented the inelasticity analysis, examples of regulations based on contingencies, benchmarking analysis and fatigue reliabilities. He emphasized that the above analysis and reliability evaluation provide instruction and explore the possibilities for technical development.

ASME Severe Accidents Management: Strengthen the cooperation on regulation revision

Mr. Christian A. Sana from ASME reviewed the ASME and JSME in relation to guidelines for severe accident management. The overall feedback indicates ASME’s SMEs consider JSME’s approach and resulting new guideline products to be very high-quality and pertinent to their intended application. And the task group’s work – shared between ASME and JSME subject matter experts – is highly valued by ASME; specifically the Nuclear Codes and Standards Department and its nuclear standards development committees.

Risk Guideline for nuclear safety: prevention and rectification

Mr. Koji Okamoto from the University of Tokyo proposed the Risk Guideline concept in the light of nuclear safety. He analyzed the reasons for Fukushima issues layer-by-layer, and pointed out the misunderstanding between utilities and regulatory authorities in the process of risk recognition and severe accident management. There is no limit for nuclear safety, the ensuring nuclear safety requires continues efforts on the risk guidance from all parties.

This forum concentrated on the analysis and feedback from severe accidents, and provided the good practices and sustainable development strategies for nuclear regulatory.