Nuclear Energy

Nuclear energy is electrical energy produced through nuclear fission — the process by which heavy atomic nuclei (typically uranium-235 or plutonium-239) split upon neutron bombardment, releasing large amounts of heat. That heat drives steam turbines connected to generators. The process produces no direct CO₂ emissions during operation.

How it works

In a nuclear reactor, controlled fission reactions take place in a fuel core. Each fission event releases neutrons that trigger further fission in neighbouring nuclei, sustaining a chain reaction. The heat is transferred to water — either directly (boiling water reactor) or via a secondary circuit (pressurised water reactor) — producing steam that drives a turbine. Uranium-235 and plutonium-239 are the most commonly used fuels; thorium-232 is an alternative that must first be converted to fissile uranium-233 inside the reactor.

Global capacity

As of 2021, approximately 442 nuclear reactors operated in 30 countries, producing roughly 10% of global electricity. Around 50 additional reactors were under construction. France generates approximately 71% of its electricity from 58 nuclear plants. The United States has 94 reactors, covering about 20% of its electricity demand. China operated 49 reactors in 2020 with 11 under construction. Global nuclear electricity generation peaked at 2,518 TWh (13.5% of total production) in 2011, before declining after the Fukushima accident prompted Japan to shut down most of its 33 reactors.

Investment costs

Construction costs per installed megawatt vary substantially between countries, as documented in detail by De Heij (Klimaatfeiten.net, 2025):

The roughly eightfold difference between Chinese and American costs reflects differences in project management, standardised design, regulatory timelines, and the availability of an experienced nuclear construction workforce. Western countries that paused construction for several decades lost much of this expertise, contributing to significant cost overruns when new projects resumed.

Small modular reactors (SMRs), currently in development, cost $11.6–20.1 million per MW, primarily because they lack economies of scale; costs are expected to fall as the technology matures.

Operating costs and LCOE

The levelised cost of electricity (LCOE) from nuclear — covering fuel, operations, maintenance, and capital repayment — ranged from approximately 3 to 11 eurocents per kWh in 2018 estimates. Correct comparisons between nuclear and variable renewables require including the cost of backup capacity for periods without wind or solar generation, grid stabilisation, and storage. De Heij (Klimaatfeiten.net, 2025) argues that omitting these system costs systematically understates the real cost of intermittent sources relative to dispatchable ones such as nuclear.

Nuclear energy in the Netherlands

The Netherlands operates one nuclear power plant: Borssele (515 MW, commissioned 1973), supplying approximately 3–4% of domestic electricity. A political decision to build two new large nuclear plants was taken in 2024.

De Heij (Food4Innovations, 2018) calculated that supplying the Netherlands’ current electricity demand of approximately 120 TWh per year would require around 10 reactors of 1.5 GW capacity at a total investment of roughly €45 billion. If electricity demand doubles due to electrification of transport and heating, 20 to 30 mid-sized plants would be needed. Electricity represents only approximately 16% of the Netherlands’ total final energy consumption of around 2,400 PJ per year, which illustrates the broader scale of a full energy transition.

Thorium reactors

Thorium-232 is a naturally occurring, relatively abundant element. In 2023, China’s Shanghai Institute of Applied Physics commissioned a 2 MWth molten salt thorium reactor demonstration plant in Wuwei, Gansu province — the first at this scale worldwide. The design uses molten fluoride salts as coolant, allowing operation at atmospheric pressure with passive safety features. China plans to scale the technology to 373 MWth for commercial testing.

Potential advantages of thorium reactors include reduced production of long-lived transuranic waste, lower proliferation risk, and the use of a more abundant fuel. The United States conducted molten salt experiments at Oak Ridge National Laboratory in the 1960s before discontinuing the programme. China’s choice of thorium is partly motivated by domestic fuel reserves and by the technology’s limited suitability for military applications.

Safety and waste

Nuclear fission produces radioactive waste that requires secure storage for thousands to hundreds of thousands of years. No permanent geological disposal facility for high-level waste was operational in Europe as of 2024, though Finland and Sweden are in advanced stages of construction. Major accidents occurred at Three Mile Island (1979), Chernobyl (1986) and Fukushima Daiichi (2011). A 2013 NASA study estimated that nuclear electricity generation had prevented approximately 1.84 million premature deaths that would otherwise have resulted from air pollution caused by fossil fuel alternatives.

Role in the energy transition

Nuclear energy produces negligible CO₂ during operation and requires a small land area relative to its output, which has renewed policy interest in many countries. Its main disadvantages are high upfront capital costs, long construction times (often ten years or more in Western countries), and the unresolved long-term storage of radioactive waste. Whether nuclear is cost-competitive with wind and solar depends critically on which system costs — backup capacity, storage, grid reinforcement — are included in the comparison.