Sustainable Nuclear Energy

by Y. Sokolov and R. Beatty

Assessment tools developed by the IAEA assist Member States in strategic planning and decision making on sustainable nuclear energy development and deployment.

Long-range and strategic planning for energy system evolution and the potential role of nuclear energy therein requires a sound understanding of the dynamics of technology change and innovation. Careful consideration of energy related infrastructures, social preferences, economic development directions and environmental constraints must be part of national nuclear energy deployment. Nuclear Energy System Assessment (NESA) is an integral part of national nuclear power development along with energy planning and nuclear infrastructure development using the IAEA ‘Milestones’ approach for first nuclear power plants. In particular, adopting a nuclear power programme has intergenerational implications and obligations extending well beyond 100 years.

Energy planning aims at ensuring that decisions on energy demand and supply infrastructures involve all stakeholders, consider all possible energy supply and demand side options, and are consistent with overall goals of national sustainable development. The decision that nuclear energy will be part of a diverse energy mix should include reactor technology selection, infrastructure development required for first plants, and an understanding of the entire range of impacts and considerations related to deploying a sustainable nuclear energy system. This must include innovations in nuclear technology and institutional arrangements that contribute to, and are caused by, global evolution.

A nuclear energy system encompasses the complete spectrum of the nuclear fuel cycle, i.e. from mining to final end states for all wastes, and associated institutional arrangements. Nuclear energy systems are characterized by complex infrastructures and long life, easily extending over several generations. In addition, developing or expanding nuclear energy requires extensive lead times and resources, especially for the design and commercialization of new and innovative components. Nuclear energy systems must be assessed holistically, i.e., from all possible angles of sustainable development, which includes three interdependent and mutually reinforcing pillars: social development, economic development and environmental protection, all linked by effective government institutions.

Nuclear Energy System Assessment using the INPRO Methodology

To assist Member States in assessing their long range strategic planning for existing or future nuclear energy systems, the IAEA’s International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) developed the ’INPRO Methodology’ with contributions from 300 international experts including some from the Generation IV International Forum (GIF). The Nuclear Energy System Assessment is a holistic approach that uses this internationally validated tool — the INPRO methodology — to support long-term planning and strategic decision making on nuclear energy development and deployment in Member States.

A prerequisite for a NESA is an energy planning study in case of newcomers — or a national energy strategy for countries with a mature nuclear power programme — that defines the potential role of nuclear in a mix of energy supply at the national level, however with due regard to regional and global trends. IAEA energy planning models assist energy planners in undertaking such studies. National authorities in charge of energy policy or nuclear energy system planning can initiate a full assessment or a scoping NESA.

A NESA with the INPRO methodology evaluates all nuclear facilities in a given nuclear energy system, from mining through to final end states for all wastes including permanent disposal of high-level waste, and all related institutional measures. It considers the complete lifecycle of nuclear facilities (‘cradle to grave’), i.e. design, construction, operation and decommissioning, and evaluates a nuclear system in the seven areas identified by the methodology developers, which together encompass the dimensions of sustainable development: economics, infrastructure (institutional arrangements), waste management, proliferation resistance, physical protection, environment (impact of stressors, and resource depletion), and safety of reactors and of nuclear fuel cycle facilities.

Countries with established nuclear programmes, as well as nuclear ‘newcomers’ who are considering embarking on new nuclear programmes can conduct a NESA to identify possible gaps in their nuclear programme and associated actions to fill the gaps. This is targeted at:

❶ Nuclear technology developers, to assess their long-term development and deployment strategy to confirm that it is sustainable and that it has the correct balance of nuclear facilities;
❷ Experienced nuclear technology users, to increase the awareness of key stakeholders and assist with strategic planning and decision making concerning the expansion of their nuclear energy system;
❸ Prospective first time technology users, to identify issues that need to be considered when deciding the step by step development of a nuclear energy system, i.e. developing the necessary nuclear infrastructure and building a first nuclear power plant.

National Assessments

Recently, several countries performed a series of national NESAs: Argentina, Armenia, Brazil, India, Republic of Korea, and Ukraine. In addition, eight countries, i.e. Canada, China, France, India, Japan, Republic of Korea, Russian Federation, and Ukraine, jointly investigated a nuclear energy system consisting of sodium cooled fast reactors with a closed fuel cycle (see box “Closed Fuel Cycle With Fast Reactors”).

The national NESA studies were conducted by countries of both technology users and developers and included different scales of assessments. Argentina and Ukraine evaluated the sustainability of their planned national nuclear energy systems by assessing all facilities of the nuclear fuel cycle. Brazil, India and the Republic of Korea assessed specific reactor designs and associated fuel cycles in selected areas of the INPRO methodology. The Brazil team chose the IRIS reactor design and assessed it in the areas of safety and economics. In addition, the Fixed Bed Nuclear Reactor (FBNR) design was assessed for sustainability in the areas of safety and proliferation resistance. The Indian study investigated the replacement of fossil fuel by hydrogen in the transportation sector. The prime objective of the Korean study was to develop a qualitative analysis to determine the level of proliferation resistance of the DUPIC fuel cycle, where spent PWR fuel is transformed into new fuel for CANDU reactors. Armenia performed a NESA primarily to familiarize national decision makers with all issues of the planned nuclear power programme of replacing the existing reactor by a larger unit around 2025.

The Joint Study explored several possible scenarios through modelling of how different nuclear technologies could contribute to fulfilling the expanded role of nuclear energy and what kinds of problems and approaches might be considered to allow an easy transition to a closed nuclear fuel cycle with fast reactors.

INPRO methodology

The INPRO Methodology is organized in a threetier hierarchy of Basic Principles, User Requirements and Criteria, consisting of indicators and acceptance limits. These elements are used in the seven INPRO assessment areas. An assessed nuclear energy system represents a source of energy consistent with a country’s sustainable development criteria, if all principles, requirements and criteria are met. If the assessment points to a gap, further R&D studies should be undertaken.

If not all components are met, a given nuclear energy system may still make a significant, interim contribution to meeting the energy needs of a country or region, but will need to change and evolve to become sustainable in the longer term. The results of a NESA can be used to guide this evolution.

An IAEA publication describes how to conduct a NESA using the INPRO methodology: Guidance for the Application of an Assessment Methodology for Innovative Nuclear Energy Systems: INPRO Manual — Overview of the Methodology (TECDOC 1575 Rev.1).

Yuri Sokolov is IAEA Deputy Director General, Department of Nuclear Energy, and INPRO Project Manager.

Randy Beatty is the INPRO Group Leader at the IAEA.