Why nuclear?

The process is called fission, and a power plant uses the heat it releases to make steam. That steam turns a turbine connected to a generator, producing electricity much as it does in other thermal power plants.

1fuel pellet

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1000 kgof coal

According to the US Department of Energy, one pellet can release roughly as much energy as 1000 kg of coal. This helps explain why so little fuel is needed. The comparison depends on the fuel and reactor.

In practice, there is less fuel to transport and it is possible to keep reserves for long periods. Uranium still has to be mined and prepared, the plant built and the spent fuel managed.

Hydro, batteries, connections to other countries and the ability to shift some demand already help balance the grid, but each has costs and limits. A good annual total also tells us little about what happens on a still night or during a drought.

Reactors can add low-carbon generation that does not depend on sunshine or wind. They also have maintenance and refuelling outages, and can experience faults. Their contribution needs to be planned alongside the rest of the system.

This is what we want studied: whether adding this option improves the outcome for Portugal. It would need to make sense in cost, emissions and security of supply, making use of the renewables we already have.

Ionising radiation occurs naturally in rocks, soil and space. Flying increases cosmic radiation exposure because there is less atmosphere above us. Some foods also contain small amounts of radioactive elements.

Being natural does not make it harmless. High doses can cause injuries and exposure can increase cancer risk. That is why worker and public exposure is measured, with limits and protective measures applied.

In Portugal, APA operates RADNET, a network that continuously monitors environmental radiation. It helps detect changes and supports the authorities’ response.

At Chernobyl in 1986, design flaws, operational decisions and a poor safety culture contributed to the destruction of the reactor and a major radioactive release. There were deaths from acute exposure and long-term health consequences.

At Fukushima in 2011, the earthquake and tsunami led to a loss of electricity and cooling. Core meltdowns and hydrogen explosions followed. UNSCEAR has not documented adverse health effects among residents directly attributable to radiation from the accident. Evacuation and displacement nevertheless had serious human consequences.

Protection means several measures working together: physical barriers to contain radioactive materials, systems to cool the fuel, training, independent oversight and emergency plans. None of these can be an excuse to neglect the others.

A reactor also cannot explode like an atomic bomb, because the fuel and conditions are different. Other accidents remain possible, including steam and hydrogen explosions.

Spent fuel starts in a pool, where water removes heat and shields radiation, and can move to steel-and-concrete containers once it has cooled sufficiently. These are the two stages of interim storage shown in the photographs.

For final disposal, the reference solution is a deep geological repository: engineered barriers together with stable rock to isolate the material. This is the approach at ONKALO in Finland. Its operating licence was granted on 22 October 2026. According to Posiva, disposal still depends on tests, inspections and STUK approval.

Radioactivity decreases over time, at different rates for different materials. Managing it requires funding, lasting institutions and community involvement. Developing the technology is part of the work; putting it into practice remains each country’s responsibility.

Investment begins long before the plant sells electricity and, if construction slips, interest keeps adding up, as the example below shows. Using a design already built elsewhere, working with experienced teams and securing stable financing can help control costs. Changing the design during construction, on the other hand, can make the project much more expensive.

Portugal already has a regulator for radiological protection and nuclear safety: APA. A power programme would require stronger capacity, trained people and preparations for suppliers, financing and spent fuel management.

Based on international experience, the IAEA points to about 10 to 15 years from initial consideration to a country’s first plant entering operation. That is a reference, not a guaranteed schedule for Portugal.

This is why we want the option studied seriously. We would need to compare whole-system costs, emissions, land, dependence on imports and the time needed. Only that analysis could tell us whether the nuclear option adds value for the country.