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Nuclear power plants are used extensively as base load sources of electricity. This is the most economical and technically simple mode of operation. In this mode, power changes are limited to frequency regulation for grid stability purposes and shutdowns for safety purposes.

However for countries with high nuclear shares or desiring to significantly increase renewable energy sources, the question arises as to the ability of nuclear power plants to follow load on a regular basis, including daily variations of the power demand.

This report considers the capability of nuclear power plants to follow load and the associated issues that arise when operating in a load following mode. The report was initiated as part of the NEA study “System effects of nuclear power”. It provided a detailed analysis of the technical and economic aspects of load-following with nuclear power plants, and summarises the impact of load-following on the operational mode, fuel performance and ageing of large equipment components of the plant.

Under the Paris Agreement, OECD countries agreed to aim for a reduction of their greenhouse gas emissions sufficient to hold the increase in the global average temperature to well below 2°C above pre industrial levels. This commitment requires a massive effort to decarbonise energy and electricity generation, a radical restructuring of the electric power sector and the rapid deployment of large amounts of low-carbon generation technologies, in particular nuclear energy and renewable energies such as wind and solar PV.

This study assesses the costs of alternative low-carbon electricity systems capable of achieving strict carbon emission reductions consistent with the aims of the Paris Agreement. It analyses several deep decarbonisation scenarios to reach the same stringent carbon emission target but characterised by different shares of variable renewable technologies, hydroelectric power and nuclear energy.

Refurbishment and long-term operation (LTO) of existing nuclear power plants (NPPs) today are crucial to the competitiveness of the nuclear industry in OECD countries as existing nuclear power plants produce baseload power at a reliable cost. A number of nuclear power plants, most notably 73 units in the United States (up to 2012), have been granted lifetime extensions of up to 60 years, a development that is being keenly watched in other OECD countries. In many of these (e.g. France, Switzerland), there is no legal end to the operating licence, but continued operation is based on the outcomes of periodic safety reviews.

This study analyses technical and economic data on the upgrade and lifetime extension experience in OECD countries. A multi-criteria assessment methodology is used considering various factors and parameters reflecting current and future financial conditions of operation, political and regulatory risks, the state of the plants’ equipment and the general role of nuclear power in the country’s energy policy.

The report shows that long-term operation of nuclear power plants has significant economic advantages for most utilities envisaging LTO programmes. In most cases, the continued operation of NPPs for at least ten more years is profitable even taking into account the additional costs of post-Fukushima modifications, and remains cost-effective compared to alternative replacement sources.

The feasibility and costs of spent nuclear fuel management and the consequent disposal of ultimate waste continue to be the subject of public debate in many countries, with particular concern often expressed over the lack of progress in implementing final disposal. Uncertainties about back-end costs and the financial risks associated with management of the back end have also been singled out as possible deterrents to investment in new nuclear power plants.

This report offers an appraisal of economic issues and methodologies for the management of spent nuclear fuel and high-level waste from commercial power reactors. It includes a review of different backend options and current policies and practices, with a focus on the cost estimates for these options and the funding mechanisms in place or under consideration in OECD/NEA countries. A generic economic assessment of high-level estimates of back-end cost impacts on fuel cycle costs is undertaken for selected idealised scenarios, by means of a simple static model. Sensitivity analyses are conducted for the evaluation of uncertainties in major components and the identification of cost drivers. Since factors other than economics are an important part of the decision-making process, an analysis of the influence of key qualitative parameters in the selection of back-end strategies is also presented in this report.

There is significant international interest in the effects of temperature on criticality safety evaluations. Improved access to nuclear data, notably thermal scattering data S(α,β) for hydrogen in ice, has made it possible to assess and deepen the understanding of the variation of criticality calculations associated with temperature.

Under the auspices of the Nuclear Energy Agency (NEA) Nuclear Science Committee (NSC) and of the Working Party on Nuclear Criticality Safety (WPNCS), Subgroup 3 was launched to study the impact of temperature through a wide range of codes, data libraries and methods. The group studied a pressurised water reactor (PWR) assembly in a thick water reflector at five different temperatures, ranging from ice to room temperature and up to reactor operation temperature. Ten organisations in eight countries participated, providing 34 sets of results.

With a view to launching the activity and obtaining results in a timely fashion, geometrical and material data from a previous WPNCS benchmark model were used in a new study to help examine the effect of temperature on criticality safety calculations.

The exercise was successful in bringing together a large number of institutions and employing a wide range of calculation codes and nuclear data libraries, thereby providing solid evidence for the conclusions drawn. The participants’ dedication made it possible to complete the exercise in two years, providing timely support to end users.

This report contains the benchmark study and results, and was endorsed at the WPNCS Subgroup 3 meeting in July 2020.

This study examines the financial risks involved in investing in a new nuclear power plant, how these can be mitigated, and how projects can be structured so that residual risks are taken by those best able to manage them. Given that expansion of nuclear power programmes will require strong and sustained government support, the study highlights the role of governments in facilitating and encouraging investment in new nuclear generating capacity.

Electricity provision touches upon every facet of life in OECD and non-OECD countries alike, and choosing how this electricity is generated – whether from fossil fuels, nuclear energy or renewables – affects not only economic outcomes but individual and social well-being in the broader sense. Research on the overall costs of electricity is an ongoing effort, as only certain costs of electricity provision are perceived directly by producers and consumers. Other costs, such as the health impacts of air pollution, damage from climate change or the effects on the electricity system of small-scale variable production are not reflected in market prices and thus diminish well-being in unaccounted for ways.

Accounting for these social costs in order to establish the full costs of electricity provision is difficult, yet such costs are too important to be disregarded in the context of the energy transitions currently under way in OECD and NEA countries. This report draws on evidence from a large number of studies concerning the social costs of electricity and identifies proven instruments for internalising them so as to improve overall welfare.

The results outlined in the report should lead to new and more comprehensive research on the full costs of electricity, which in turn would allow policy makers and the public to make better informed decisions along the path towards fully sustainable electricity systems.

All low-carbon solutions will be required to achieve the world's net zero targets. Nuclear energy has a role to play in meeting this need. A wave of innovation in small modular reactors (SMRs) is advancing quickly with the potential to help decarbonise hard-to-abate sectors. Progress is real and is positioned to accelerate pathways to net zero. SMRs could replace coal on-grid, fossil fuel cogeneration of heat and power for heavy industry, diesel at off-grid mines, as well as producing hydrogen and synthetic fuels.

Looking beyond technical feasibility, The NEA SMR Dashboard defines new criteria for assessing real progress in six additional dimensions of readiness: licensing, siting, financing, supply chain, engagement, and fuel. The first volume of the NEA SMR Dashboard assessed the progress of 21 SMRs. This second volume tracks the progress of an additional 21 SMRs around the world.

Each nuclear power plant, fuel cycle facility and nuclear research and test facility that is operating today will eventually reach the end of its useful life and cease operation. During the period of its decommissioning, it is important to properly manage the health and environmental hazards and physical protection measures of the shutdown facility in order to protect the health and safety of the public and workers and to safeguard any nuclear materials. In this regard, the nuclear safety regulatory body is responsible for independently assuring that decommissioning activities are conducted safely, that radioactive materials and spent nuclear fuel are disposed of properly and that the site is in an acceptable end state.

The purpose of this report is to describe the broad range of safety, environmental, organisational, human factors and public policy issues that may arise during the decommissioning of nuclear reactors and that the regulatory body should be prepared to deal with in the framework of its national regulatory system. The intended audience is primarily nuclear regulators, although the information and ideas may also be of interest to government authorities, environmental regulators, nuclear operating organisations, technical expert organisations and the general public.

Regulators are major stakeholders in the decision-making process for radioactive waste management. The NEA Radioactive Waste Management Committee (RWMC) has recognised the value of exchanging and comparing information about national regulatory practices and having an informal, international network for discussing issues of common concern. The RWMC Regulators’ Forum provides considerable opportunity for such activities.

This report presents the initial results of the Forum’s work. Information is given for 15 NEA member countries in a format that allows easy accessibility to specific aspects and comparison between different countries. It includes an array of facts about national policies for radioactive waste management, institutional frameworks, legislative and regulatory frameworks, available guidance, classification and sources of waste and the status of waste management. It also provides an overview of current issues being addressed and related R&D programmes.

This report assesses the role that nuclear energy can play in supporting the transition to a low-carbon energy system. It begins by considering the greenhouse gas emissions from the full nuclear fuel cycle, reviewing recent studies on indirect emissions and assessing the impact that nuclear power could make in reducing greenhouse gas emissions.

The report provides estimates of the construction rates that would be needed to meet the projected expansion of nuclear power foreseen by many energy scenarios published by international organisations. It then assesses the economic, technical, societal and institutional challenges represented by such an expansion to identify the most significant barriers. The capacity of nuclear power plants to operate in an electricity system with a large share of renewables, and the impact of smart grid technologies are also examined. Finally, long-term prospects for nuclear energy are discussed in terms of development of new reactor and fuel cycle technologies, non-electric applications and new operational and regulatory constraints that could arise as a consequence of climate change.