Optimal strategies for stakeholders of Fukushima nuclear waste water discharge in Japan

The Japanese government intends to discharge radioactive nuclear waste water from the Fukushima nuclear reactor into the Pacific Ocean, which will cause irreversible and catastrophic ocean ecological pollution. In response to this irresponsible practice, there are strong domestic and international objections. However, the Japanese government's decision to discharge has not been changed. This study uses evolutionary game theory to construct a game model of the optimal strategic behavior of the Japanese government, stakeholder countries, and the domestic public in the proposed nuclear waste water discharge and explores the stable equilibrium point of the strategy combination by analyzing the interests of the three decision makers. The results are shown as follows: first, the participation of stakeholder countries will prevent the Japanese government from violating the marine environmental policy. This will ensure a safe resolution of the nuclear waste water incident in Japan. Second, the participation of the Japanese public can serve as a synergistic regulation. However, there is also a possibility of a free-rider phenomenon. Third, the strategy choice of the Japanese government is mainly related to factors such as the cost of nuclear waste water treatment devices and the storage cost of nuclear waste water. Lastly, relevant countermeasures and recommendations are put forward to promote effective monitoring by stakeholder countries and domestic people. It also promotes the Japanese government to abide by the marine environmental policy. Studying the strategic choices of stakeholders can influence recommendations for the formulation of international marine environmental policies under the current situation.