The Future of Radiological Protection


Scientific Improvement on Social Understanding of Tritium, Ten Years After the Fukushima Nuclear Accident

Author(s): Yoshiyuki Mizuno
(Kyoto Women's University, Japan; Visiting Researcher of The Great East Japan Earthquake and Nuclear Disaster Memorial Museum, Japan)



The present work deals with a scientific improvement of social education or understanding on radioactive tritium by laypeople, which is even possible after ten years of Fukushima nuclear accident. This work is actually motivated since the normal way of tritium dilution into ocean within the standard regulatory concentration had been hampered firstly by Korean Government in May 2011. In addition, thereafter the tritium issue has become one of the difficult issues to solve urgently, but without any success until 2020. The answer was the huge number of storage tanks with tritium in water.

The dialogue meetings between the fishermen and administrative stakeholders were repeatedly held, but without success to overcome the foreseen hoax or rumors leading to the social stigma. Heretofore, we have encountered once a hope for political decision in August 2020, when the new Cabinet was then elected.  But unfortunately, the new Minister of the Ministry was unable to make a decision with a confidence, which must be actually a hard issue even as a tangible scientific knowledge. Actually no one has witnessed the generation of tritium.

Scientific visualization with nuclear modeling of tritium generation, that is generated in atmospheric nuclear spallation reaction by cosmic rays, has been by no way sufficient until now. In order to overcome the above-mentioned social difficulty on educational facet of tritium as a tangible science, I have performed a Monte-Carlo simulation so as to reproduce the measured value of tritium concentration and its generation rate in the atmosphere. The result was in a reasonable agreement with the measurement. On top of this, according to this simulation, several new features were predicted with new observables on tritium generation. Once this prediction is confirmed by another experiment, the social trust on scientific knowledge on tritium will be shared with laypeople in society, not to mention the fishermen in Fukushima.

In parallel, I have performed a pedagogical “Fermi estimate” on possible separation of tritium by a centrifuge apparatus, which is possible and rather easily demonstrated in laboratory. This proposal seems likewise effective to transform the elusive tritium into a tangible substance in an educational and scientific theory and experiment.

In the present work, I concentrate on the educational aspect in illuminating the difficulty of tritium understanding as a social difficulty of radiation protection.

Keywords: tritium; simulation; separation; concentration


Marjorie Gonzalez

Thank you, I appreciated this talk. This is still one of the most asked questions that I get about the Fukushima accident here in Canada, and it does affect how the public views the risks from nuclear energy.