This is a Q&A document prepared by The Finnish Greens for Science and Technology. In the document, we try to answer some common questions about nuclear energy based on the latest scientific information. If you have any questions feel free to contact us at [email protected]. Viite – The Finnish Greens for Science and Techonology is a member association of Greens of Finland.


  1. Can we achieve our climate goals without nuclear energy?
  2. Is nuclear power sustainable?
  3. Is nuclear power safe?
  4. How harmful is nuclear waste?
  5. Is nuclear power too slow to build?
  6. Is nuclear power too expensive?
  7. How does nuclear energy affect the EU’s climate ambition?
  8. Should EU sustainable finance taxonomy include nuclear?

Appendix: Common misunderstandings regarding nuclear

1. Can we achieve our climate goals without nuclear energy?

Looking at global energy consumption, the situation seems bleak. Over 80% of global consumption still comes from fossil fuels. Consequently, the IPCC report notes that, above all, the capacity of low-emission renewables – wind, solar and geothermal energy – must be multiplied in order to combat climate change. Additionally, IPCC report scenarios for 1.5 degrees warming require a two to sixfold increase for nuclear power. 

Traditionally, opposing nuclear power is associated with trust in a notion, created in the media and in public discourses, that a problem-free renewable-energy based solution is waiting for us just around the corner, and that this solution will cover all future energy needs. For example, with news about how Denmark has been run entirely by renewable energy for a day, an image is created that soon the same solution will work everywhere. At the same time, the media overlooks the fact that this is about electricity consumption; the total energy consumption by Denmark is still largely based on fossil fuels. Even though low-emission renewables are likely to be the most significant future energy form, renewables alone may not be able to replace all fossil energy forms in, for example, heating or increasing electrification. Wind and solar energy have challenges related to the variability of the energy production and they often need support from other energy sources. Therefore, it is worth keeping various nuclear-power based solutions as part of the energy mix.

The International Renewable Energy Agency (IRENA) predicts that, in 2050, renewables could produce two thirds of all energy needed. When realized, this would be a great achievement! However, also the last third of the energy required in 2050 must be produced by low-emission means and not by fossil energy sources. Additionally, the report by IRENA, unfortunately, estimates that heating would largely be based on bioenergy. This is not a sustainable solution. Bioenergy cannot be sustainably increased by much, as forests must be kept as carbon storage, and be partly utilized as higher-value products, such as in wood construction. Also, human action – farming and gathering of nature’s biomass production for human use – is already driving a rapid loss of biodiversity and shrinking of species populations. When the challenge is as enormous as it is, low-emission renewables and nuclear power should not be pitted against each other. Such juxtaposition only benefits the fossil industry.

2. Is nuclear power sustainable?

To stop climate change, it is essential to minimize the carbon emissions from energy production. The picture below shows that nuclear power has one of the smallest carbon footprints of all electricity sources per unit of energy produced. 

Median values for lifecycle emissions of different electricity sources: IPCC 2014

Some criticize nuclear power for the problems related to mining uranium. However, this kind of criticism makes one wonder what the better option would be, as all sources of energy have their own problems related to the required minerals. Renewable sources of energy require more different metals per unit of energy than nuclear power does. Nonetheless, in order to replace fossil fuels, we will need many times more low-emission renewables than we currently have.

The image below indicates the land use footprint of nuclear power and wind power based on actual projects. The nuclear footprint is likely overestimated, since the uranium mine depicted here produces more than three times what is used by the nuclear power plant, and the site can accommodate at least a fourth large reactor. The footprint of wind power is underestimated, as the mines and backup power needed by wind power are not included.

Data for wind park is from Environmental Impact Assessment of Oosinkangas wind park, data for nuclear is from google maps.

3. Is nuclear power safe?

Many of those opposing nuclear power originally formed their position as a reaction against the indifference towards risks in the Soviet Union, and in particular, against the resulting Chernobyl accident. This is understandable. However, there have been no accidents in plants constructed after 1980, and statistically speaking, nuclear power is actually the safest form of energy.

Nuclear power has also been opposed due to fears of nuclear arms proliferation. However, if a country wants to make nuclear weapons, it can make them also without civilian nuclear reactors.  Using modern nuclear reactors to make weapons material (plutonium), is actually multiple times more expensive, and easier to detect than other options, such as enriching uranium with centrifuges (e.g. Iran) to weapons grade or using a simple graphite pile to make plutonium (examples in and after Second World War). IAEA supervises the use of nuclear power and the use and transport of nuclear materials to prevent nuclear arms proliferation. Here, a strong global civilian nuclear community is a great asset. 

4. How harmful is nuclear waste?

Spent nuclear fuel is also a common safety concern. However, nuclear waste management is already heavily regulated by the laws and procedures both in the EU and in the member states. In practice, spent nuclear fuel has never harmed anyone, anywhere. Spent nuclear fuel emits radiation and must be kept separate from the biosphere. This is not very hard: a few meters of water or concrete is adequate to stop the radiation.  In the long term, it is preferable (safer, cheaper) to store the spent fuel for example in deep geological storage, or use it to make new nuclear fuel and low carbon energy in breeder-reactors. 

The graph below shows the average radioactive doses humans get, by source (Data: United Nations Scientific Committee on the Effects of Atomic Radiation, 2008. As can be seen, the nuclear fuel cycle, which includes spent fuel, is barely the size of a rounding error.

Finland’s spent nuclear fuel repository Onkalo sets an example for the final disposal of nuclear waste. The independent nuclear and radiation regulator STUK has stated that the repository can be built to be passively safe. The margin of safety is such that even the purely academic modeling exercise, where everything goes wrong, the maximum doses someone might get, at 0.00018 mSv, are in the neighbourhood of a million times too small to cause any significant harm to the local population ten thousand years into the future. 

5. Is nuclear power too slow to build?

Some argue that nuclear reactors are too slow to manufacture compared to the immediacy of the climate crisis. The reactors take multiple years to plan and build. However, the EU is likely still many years or decades away from ending emissions from its energy production – and even then, the energy production infrastructure needs constant rebuilding. Therefore, the nuclear reactors that start to generate power years or decades from now will help in reducing the remaining emissions. If nuclear energy is not an available tool to reduce emissions, then reaching carbon neutrality might take longer, as we argue in the next section. 

Furthermore, the reactor production is not always as slow as some of the worst recent examples indicate. According to IAEA’s PRIS database, the plants built during 1990s and 2000s took less than six years to build on average, and currently the average building speed in China is around 5-6 years. The recent delays in western nuclear projects are largely due to lost expertise and supply chains during the 30 years of not building nuclear and building new First-Of-A-Kind plants that had unfinished designs when construction started. These can all be mitigated, leading to faster projects that stay on budget better.

6. Is nuclear power too expensive?

Some 10-20 years ago, wind and solar were very expensive. Since then, we have had extremely supportive policies and poured billions of euros in subsidies and tax-breaks for wind and solar. They have proliferated, and they have become cheaper. As can be expected, humans get better and more efficient in the things they do. 

This can be observed in nuclear power as well. Several decades of not building nuclear in Europe led to prohibitively expensive “First-of-A-Kind” projects, plagued with delays and problems. Yet elsewhere, the rest of the world (ROW)  kept on building nuclear, and can do it at low cost, relatively on time and on budget. This can be seen in the image below, taken from the recent global study “Nuclear Cost Drivers Project” done for the Energy Technologies Institute. 

As it is abundantly clear that we need much more nuclear power to mitigate climate change effectively and within the required timeframe, it would make sense to make building it cheaper. Having a program to build nuclear, instead of politically risky one-off projects every decade or so, can substantially bring down nuclear energy’s costs, halving them or even more. 

Nuclear plants are big and time-consuming project even when they are successful. Therefore, the cost of capital also plays a very important part in the levelized cost of electricity (LCOE). This can be seen by inspecting the effect of changing the discount rate of nuclear energy. Let’s take the IPCC 2014 AR5 report as an example, as it used a rather high 10 % discount rate for nuclear energy. Lowering the discount rate (or the interest rate for financing by lowering political and/or market risks and reputation risk for financing, for example through inclusion in the Taxonomy for sustainable activities in the EU) to a rate that is compatible with a liveable future and with our goals of sustainability, can halve the LCOE of nuclear, as seen on the graph below. 

So yes, we can make nuclear energy as expensive as we want, and have been doing that for a long time now, but there is nothing inherently expensive about nuclear energy. It is extremely dense energy, uses materials and land very efficiently compared to other clean energy sources and provides us with reliable energy services – something that wind and solar alone are yet unable to do at higher penetrations. 

7. How does nuclear energy affect the EU’s climate ambition?

Strengthening EU Climate targets generally requires unanimity among the member states. In general, EU countries with the  most carbon-intensive economies are the least supportive to strengthening the targets. Improving the decarbonization prospects of carbon intensive member states is, therefore, an important prerequisite towards strengthening the climate targets.

Decarbonization prospects depend significantly on the financial aid from the EU and on the investment conditions for low emission energy sources. Regarding this, the availability of funding for nuclear power plays an important role. Currently, governments in many EU member states view nuclear energy as an important part of their decarbonization plans. Hungary and the Czech Republic opposed the 2050 climate neutrality target until very recently. Both considered the investment conditions for nuclear energy an important prerequisite for their support. Poland still opposes the target, and it is also planning on extending its nuclear energy production. The Polish Minister of Climate recently sent top EU officials a letter, stating that EU energy and climate policy needs to be developed in a technology neutral and evidence-based manner, including the European Green Deal and Sustainable Finance Packages, and that further prejudice against nuclear will hinder progress and prevent the achievement of 2050 climate goals. 

EU climate ambition needs to be strengthened further in the future. To achieve this, it may be essential to provide good investment conditions to all safe and low emission energy sources in the member states. 

8. Should EU sustainable finance taxonomy include nuclear?

The investment conditions for nuclear power are closely related to how the EU formulates the sustainable finance taxonomy, and how rigorously the “do-no-harm”-principle is applied on nuclear power. The EU taxonomy significantly affects the availability of investment funding for different energy sources. Consequently, investment conditions affect the financial feasibility of low emission energy sources. The taxonomy was commissioned to be a technology neutral tool for sustainable investments, yet nuclear power is treated completely differently when it comes to Do-No-Significant-Harm criteria. See more information on the “Sustainable Nuclear Assessment Report” downloadable here

At this point, we cannot accurately predict which low carbon energy sources will be most economically efficient. However, restricting the pool of available choices in advance will lower the expected return of future sustainable investments. The more options available in the taxonomy, the better is the freedom for investors to invest in most profitable projects from their perspective. Therefore, the invested sums will be higher and the amount of energy produced with a given amount of invested money will be greater. The latter also applies to the EU’s 100 billion euro Just Transition Mechanism. European Commission proposed to exclude nuclear energy from it.

The expected amount of investments in low carbon energy is crucial for member states’ willingness to stop using high emission energy sources. Investments will be greater when interest rates are lower – for example due to inclusion in “green” or “sustainable” portfolios that the EU Taxonomy aims to facilitate. Member states may view that using only renewable energy sources – with their variability and storage problems – is a too expensive path for decarbonisation. The wider the decarbonization toolbox available to EU countries, the higher is their confidence in supporting ambitious emission reduction goals. 

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Appendix: Common misunderstandings regarding nuclear

There are a couple of commonly circulating misconceptions about nuclear energy. While this document cannot cover them all in detail, two examples are provided below. One has to do with the lifecycle emissions, the other with nuclear accidents and their health effects. These cases are representative of the whole, as often categorical anti-nuclear arguments are based on one or more of these three: 1. They are factually incorrect or based on a fringe-study that has very different results compared to mainstream science and meta-studies. 2. They are based on logically fallacious arguments. 3. They are presented in a “vacuum”, meaning no relevant comparisons are made. For example: Nuclear is “risky” only if you do not compare it to other energy sources or the lack of modern energy services. 

Lifecycle emissions

Although both the IPCC (2015) as well as National Renewable Energy Laboratory in the United States has found nuclear energy’s lifecycle emissions to be extremely low (comparable with wind power) in their wide meta-studies, people surprisingly often think that nuclear has somewhat high lifecycle emissions. There are a couple of reasons for these misconceptions.

Studies have been done that have found higher numbers. There are a number of problems with these studies, and some of them have not been peer-reviewed. For example, they can:

  • Use very low ore grade for uranium mining
  • Use outdated enrichment technology not in use anymore (gaseous diffusion vs. centrifuges that are ~50 times more energy efficient).
  • Assume larger energy use for uranium mines than can be verified from real world data. For example, the commonly cited non-peer reviewed “Storm & Smith study” notes that Rössing uranium mine in Namibia uses more energy each year than the whole Namibian state consumes, and roughly 80 times more than what the records of the mining company say it uses.
  • Assume that building and operating nuclear power plants use much more energy than they use in reality. Again in the Storm & Smith study, they assumed that the Swedish Forsmark nuclear power plant construction used 240 petajoules of energy, while the number from the independently audited Environmental Product Declaration was 8 petajoules.  

And so forth. The aforementioned Storm & Smith study is cited in other studies as a source (such as the one by Benjamin Sovacool – which is also often presented as “evidence”), which are then cited in reports by organizations such as the IPCC. The important thing to remember is that the studies done by the IPCC and NREL were meta-studies, so they included all relevant individual studies and can, therefore, be considered to be the nearest thing to a scientific consensus. 

Another source of confusion might be the fact that several environmental organizations, for example WWF, have deemed it necessary to use an arbitrary number – comparable to natural gas or coal, for example – for nuclear emissions in their reports and studies for no sensible reason. If one repeats things like this often enough, many people will start to believe them, even if they have no base in reality. 

Nuclear accidents

What about the nuclear accidents? Most people have strong and horrific images in their mind when they think of nuclear accidents, and there are many reasons for these images. But such a question deserves a credible and science-based answer. 

Of the three major civilian nuclear accidents, only Chernobyl caused any verifiable casualties. And even Chernobyl was not the disaster many think it was. According to UNSCEAR’s latest, most comprehensive report to date on Chernobyl:

  • 134 plant staff and emergency workers suffered acute radiation syndrome (ARS) from high doses of radiation.
  • In the first few months after the accident 28 of them died.
  • Although another 19 ARS survivors had died by 2006, those deaths had different causes not usually associated with radiation exposure.
  • Further, some 6,000 thyroid cancer cases were reported in the three most affected countries of Belarus, Ukraine and four most affected regions in the Russian Federation. 15 of them had proven fatal, although very likely not all of them were caused by the Chernobyl fallout. 

At most, there are 62 confirmed fatalities from the worst nuclear accident in our history. Statistically, there might be some 4,000 extra fatalities all in all due to the radiation from the Chernobyl accident, according to some models. However, the models have what the UNSCEAR calls unacceptable uncertainties at these low doses and has recommended that they are not to be used for epidemiological purposes,

UNSCEAR stands for United Nations Scientific Committee on Atomic Radiation. They arguably have the best experts and sufficient resources to carefully study and review studies done by others. Yet even in mainstream media one sees vastly larger numbers cited for deaths from nuclear accidents.

The common misconceptions of hundreds of thousands or even millions of casualties come from non-peer reviewed studies that have very clear problems in their methods and reasoning and have no evidence to back their claims up. One such study was called TORCH. It came up with 30,000 to 60,000 extra fatalities, mainly by misusing the models mentioned above. Greenpeace also made their own report, and they came up with 93,000 fatalities. The method was rather curious: any area that had any amount of fallout was included. If there were any increased fatalities in that area after 1986, these were counted as being due to Chernobyl. This dubious method meant that the increased fatalities that were due to liver cirrhosis in the area of the Soviet Union, dissolved five years after the accident, were promptly attributed to Chernobyl.

There are also other estimations of casualties that are commonly used but are not fact-based. Alexei V. Yablokov, one of the authors involved in the Greenpeace report, a former member of Russian Academy of Science and one of the founders of Greenpeace Russia, wrote a book called Chernobyl: Consequences of the Catastrophe for People and the Environment (2007). It is based mainly on a wide variety of materials written in the Slavic languages. The book claims that around a million humans have died or will die due to the Chernobyl accident. In addition to blaming liver cirrhosis and other diseases that have no known connection with radiation, the book makes other claims that are proven to be wrong. For example, a study concerning the area of Tampere concluded that birth defects had decreased after the Chernobyl accident but Yablokov in his book generalized the study to cover the whole of Finland and changed “decreased” to “increased”. 

Further readings

Partanen, R., Korhonen, J.M., The Dark Horse: Nuclear Power and Climate Change (2020). Link.

Partanen, R., Korhonen, J.M., Climate Gamble – Is Anti-Nuclear Activism Endangering Our Future? (2017). Link.Goldstein, J., Qvist, S., A Bright Future: How Some Countries Have Solved Climate Change and the Rest Can Follow, PublicAffairs (2019). Link.