High-level radioactive waste disposal problem

In Japan, high-level radioactive waste (hereinafter, "HLW") refers to the vitrified object of waste liquid that remains after reprocessing to remove uranium and plutonium from nuclear fuel used in nuclear power generation. In contrast, in countries that have not adopted a reprocessing policy, spent nuclear fuel itself is considered HLW. In any case, such forms of waste have an extremely high level of radioactivity. In fact, it will take 100,000 years for the radioactivity to fall to levels that are considered safely approachable by humans.

Given this long-term risk, the form of HLW disposal must give ethical consideration to future generations. Many of the countries with nuclear power plants are promoting geological disposal in which HLW is buried deep underground, and in some respects, geological disposal considers intergenerational equity. It is unfair to leave the risk and burden of HLW to future generations who are neither the generators nor the beneficiaries of that HLW. Accordingly, isolating HLW deep underground was considered an ethical method which will eliminate the need for future generations to deal with the HLW. In Japan, the Designated Radioactive Waste Final Disposal Act was enacted in 2000 and the decision was made to proceed with geological disposal.

A trade-off between two types of equity

However, there are some ethical concerns associated with geological disposal. One is the issue of risk. Confining HLW underground for thousands to tens of thousands of years is fraught with uncertainty. If factors such as sudden underground changes were to cause radioactive materials to leak earlier than expected and enter the human environment through groundwater, etc., the resulting risks and burdens would be thrust upon future generations. In such a situation, intergenerational equity would be compromised.

Another issue of geological disposal is the difficulty of leaving decision-making authority to future generations. The final disposal of HLW deep underground makes recovery difficult. Consequently, even if superior technology for disposal and utilization were to be developed at some point in the future, the application would not be possible. Ideally, future generations should have the right to decide for themselves how to deal with HLW. Engaging in geological disposal will significantly narrow the scope of decision-making authority held by future generations, thereby making it difficult to achieve "intergenerational equity in decision-making authority."

An alternative approach is long-term storage of HLW near the surface while engaging in monitoring. This method would make it possible to immediately deal with any leak of radioactive materials. It would also ensure the recoverability of HLW, so it leaves the decision-making authority to future generations. Even so, management near the surface also has issues of uncertainty. Factors such as natural disasters, terrorism, war, or recession could cause radioactive materials to leak from storage facilities, or future generations becoming unable to continue managing the materials. Above all, management near the surface imposes the risks and burdens of waste management on future generations, who are neither HLW generators nor beneficiaries. Once again, it fails to achieve "intergenerational equity in burden."

Both geological disposal and management near the surface have their own unique risks. Moreover, if HLW is buried underground so as not to leave the burden of management on future generations, it will limit the decision-making authority of future generations. On the other hand, management near the surface with the intent of leaving decision-making authority to future generations will force future generations to bear the burden of management. In this way, there is a trade-off relationship between "intergenerational equity in burden" and "intergenerational equity in decision-making authority." For these reasons, it is impossible to achieve full intergenerational equity on such issues, at least for the time being.

Geological disposal considering reversibility and retrievability

In 2015, Japan revised its Basic Policy on Final Disposal of High-Level Radioactive Waste to clearly state the need to ensure the reversibility of geological disposal policy and the retrievability of HLW. The revised Basic Policy states that HLW will be stored in an underground geological disposal facility in a retrievable form, thereby leaving the possibility of using new technology to future generations, while at the same time deciding in stages whether to proceed with disposal processes that involve complete burial.

However, this does not eliminate the equity trade-off. The risks and burdens of managing HLW will occur as long as reversibility and retrievability are ensured. On the other hand, sealing a repository and ceasing to monitor the HLW will create risks inherent in burial and limit the decision-making authority of future generations. In summary, it is not possible to simultaneously achieve two types of equity simply by gradually transitioning from a state emphasizing "intergenerational equity in decision-making authority" to a state emphasizing "intergenerational equity in burden."

Furthermore, once a disposal site is constructed, there may be resistance to backtracking on policy from the viewpoint of cost and labor. This may lead to a stronger tendency to proceed with final disposal. If such bias were to lead to decision making without consideration for future generations, it would be ethically problematic.

Institutionalization of iterative and sustained deliberation

From November 2020, literature surveys on geological disposal were started in Suttsu Town and Kamoenai Village in Shiribeshi, Hokkaido. The survey was an attempt to decide where to build a geological disposal site based on Japan's geological disposal policy. However, there is another matter which must be considered first.

Securing reversibility and retrievability means relinquishing part of intergenerational equity in burden that was the original aim of geological disposal, and instead moving toward considering intergenerational equity in decision-making authority. This change in ethical assumptions is fundamental. Management near the surface can be a leading option if we consider intergenerational equity in decision-making authority. In that case, we must reconsider whether it is better to engage in management near the surface or in underground management that anticipates final disposal, while examining the risks and costs of each method. Only after holding repeated discussions on such issues should we decide the form and location of facilities.

More than 20 years have already passed since Japan made the decision to promote the geological disposal policy. During that time, new ideas have emerged in intergenerational ethics related to HLW. Also during that time, a new generation has been born that has little involvement in the generation of HLW. This new generation is unable to exercise decision-making authority over disposal policy. Now that the concept of reversibility of disposal policy has been introduced, geological disposal should no longer be maintained as a fixed and immutable policy. Instead, we should consider a state in which disposal policy is subject to iterative and sustained deliberation, and new ethical ideas and the opinions of new generations are flexibly applied to policy.

Of course, some people may be of the opinion that easily overturning the stipulations of national law is undesirable from the viewpoint of the rule of law. However, it is difficult to predict future trends in the issues that will have a long-term impact on future generations and communities such as the disposal of HLW. Indeed, imperfections in initial decisions may become apparent at a later time. Such long-term risks seem to require institutional mechanisms built into policy for the purpose of periodically reviewing, updating, and revising initial decisions.

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[Reference Literature]

Tsuyoshi Teramoto, Limitations of Intergenerational Equity in the High-level Radioactive Waste Management, Environmental information science, 50 (3), 48-52, 2021.

Tsuyoshi Teramoto, "Houshaseihaikibutu To Sedaikanrinri" (Radioactive Waste and Intergenerational Ethics), Mirai No Kankyo Rinri Gaku (Environmental Ethics for the Future), written and edited by Akihiro Yoshinaga and Mayumi Fukunaga, Chapter 3, Keiso Shobo, 2018.

Tsuyoshi Teramoto／Professor, Faculty of Science and Engineering, Chuo University
Area of Specialization: Philosophy and Ethics

Tsuyoshi Teramoto was born in Nagoya City in 1974.
He completed the Doctoral Program of the Philosophy Course in the Graduate School of Letters, Chuo University in 2007. He holds a PhD in philosophy.
He served as Assistant Professor and Associate Professor in the Faculty of Science and Engineering, Chuo University before assuming his current position in 2022.

His current main research theme is to use an ethical perspective to examine social issues related to the environment, science, and technology.

His recent publications include Resilience to the Future: Collaboration among Science, Politics and Society, (co-authored, Yuhikaku Publishing, 2022).
His translated works include Sustainability: What Everyone Needs to Know by Paul B. Thompson and Patricia E. Norris, (Keiso Shobo, 2022) and Environmental Justice: Creating Equality, Reclaiming Democracy by Kristin Shrader-Frechette, (co-translated, Keiso Shobo, 2022).

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