Nuclear in Bullet Points

Written by on May 29, 2025

The goal of this page is to provide a quick summary of key facts related to Nuclear Energy. Deeper Analysis and Explanations are left to dedicated articles and sources. I care a lot about acknowledging the work of other people, so here is a list of websites, associations and institutions from which these data are mostly based.

As always if you think that some of the data are not correct or are presented in a biased way, please let me know ( in a polite way please).

Before reading further test your knowledge about nuclear by taking our quiz here .

Nuclear Safety

Nuclear Power has a low number of deaths per TwH of electricity produced

It is comparable to solar and wind

Nuclear Accidents have a limited amount of deaths

Chernobyl: between 300 and 500. Numbers from OurWorldInData

2 workers died in the blast
28 workers and firemen died in the weeks after due to acute radiation Syndrome (ARS)
19 ARS survivors had died later by 2006; most were from causes not related to radiation, but it’s not possible to rule all of them out (especially five that were cancer-related)
96-385 due to thyroid cancer due to Milk contamination.

Fukushima: 1 dead because of actual radiation, 2314 because of evacuation

Nuclear Carbon Emissions

Generating Electricity with Nuclear Power is the most climate friendly way of doing it.

Nuclear Construction Times

Median construction time of nuclear power plants worlwide varied a lot in the last 75 years, between 40 and 120 months.

There is a significant difference in construction times between Europe and China. Page 22 of IEA report

Median time to build (not including planning time) nuclear power plant in Europe in the last 30 years is around 12 years. Notable example of plants with delays and cost overrun:

Olkiluoto-3 in Finland: based on the European Pressurized Reactor (EPR) model

Original cost was €3 billion, actual final cost is around €11 billion.
Started in 2005, original completion timeline should have been in May 2009 but it entered service only in Aprile 2023.
More info about Nuclear Energy in Finland can be found here

Flamanville 3 in France: based on the European Pressurized Reactor (EPR) model

Original cost was supposed to be €3.3 billion, latest cost estimations are €19.1 billions.
Started in 2007, original completion timeline should have been in 2012 but it was connected to the grid in December 2024.

Median time to build (not including planning time) nuclear power plant in China, Japan and South Korea in the last 30 years is around 5-6 years. Notable example of plants that were built quickly:

Korea Ulchin Unit 5 in South Korea. Started in October 1999 and finished in July 2004 for a total of around 5 years
Onagawa Unit 3 in Japan. Started in January 1998 and finished in January 2002 for a total of around 4 years
Yangjiang Unit 1 in China. Started in December 2008 and finished in March 2014 for a total of around 5 years

Not clear why there is such a huge difference but some reasons can be:

Specialised Workforce: building nuclear power plants requires a specifically trained workforce. Countries that build nuclear plants often can benefit from economy of scale.
Regulations: some countries might have regulations that make it easier to build fast.
Engineering Complexity: building multiple times the same type of nuclear power plant likely helps reducing the times.

Nuclear Costs

The median price for building nuclear power plants is quite high and it increased between 2009 and 2019.

It’s quite hard to compare different electricity sources because for example renewables require energy accumulation and investment in the grid which are typically not included in their costs.

Nuclear Waste

90 % of the waste is considered Low-Level and is mostly made of normal objects that became lightly radioactive after being used in the nuclear power plant. Example of this are work clothes. The radioactivity in these objects is short lived.
7 % are intermediate level waste, like filters and steel components.
3% constitutes high level waste. Note that about 97% of the fuel can be recycled.

Nuclear Capacity Factor

Nuclear power plants run almost always at full capacity, meaning that they almost always generate their theoretical maximum amount of power.

Unfortunately most of the other climate friendly electricity source have a low capacity factor ( with the exception of hydropower)

Nuclear Power Plants Duration

Typically Nuclear power plants lasts for 40 to 60 years.
Some countries are considering to extend this duration to 80 years.

Nuclear Power Plants Development

China is currently the nation building the most Nuclear Power Plants

Nuclear Land Use

Nuclear is the energy source that requires the less amount of land