How Long Does It Take To Build a Nuclear Reactor?
Let’s take a look at the data.
That the EU has moved to classify investment in natural gas and nuclear energy as green has caused an outcry across European civil society, albeit to different people for different reasons. While some praise gas as a lower-carbon transition fuel on the way towards 100% renewable energy, others point to France’s low energy-related emissions and promote more investment in the nuclear sector. Now, the risk of gas shortages due to the Russia’s invasion of Ukraine has rekindled the debate around the role of nuclear power in the energy transition.
Data from the IPCC (2014) shows that nuclear energy is one of the least carbon intensive energy sources we have. At about 12 gCO2eq/kWh, only wind power emits less greenhouse gases per kilowatt-hour.
Despite some high-profile disasters, nuclear power is also one of the safest sources of energy we have. According to estimates by OurWorldInData, each terawatt-hour of nuclear energy is responsible for about 0.03 deaths. For perspective, compare that to the 24.6 deaths/TWh from coal (mostly due to air pollution).
Among the numerous problems with nuclear power (storage of nuclear waste, centralization of energy production, nuclear weapons proliferation, national security concerns, price, fuel availability, etc.), a factor that has the most practical impact on its success for the transition away from fossil fuels is how fast we can build nuclear power plants. Construction time is one of the main problems of nuclear power limiting its usefulness in the problem we have to solve right now.
The argument goes that nuclear power plants would take too long to build to be of any use now. So, how long does it take to build a nuclear reactor?
Luckily, the International Atomic Energy Agency (IAEA) has compiled a neat overview of all nuclear reactors — those in operation, in planning, under construction, and even those permanently shut down.
What we are analyzing here is the time from the start of the construction (i.e., the first pouring of concrete) until the reactor is connected to the power grid for the first time.
We then average this construction time over all operational and shut down reactors. The average construction time is almost exactly seven years. This figure comes with a large spread, however: while the shortest construction time was just under two years, the longest took almost 43 years to complete! The standard deviation is about four years, meaning that about 68% of all reactors are completed between three and eleven years.
How does a reactor’s capacity factor in? Surely a larger reactor like China’s Taishan units (1660 MW each) will take longer to build than a research reactor like Germany’s first test reactor in Kahl (150 MW) or the world’s smallest reactor still in operation, Russia’s Bilibino reactor (11 MW).
Plotting reactor construction time vs. electrical nameplate capacity reveals an interesting relationship. While the construction time does increase with capacity, it does so only to a very small degree. Based on a best-fit linear regression, we can estimate the average reactor construction time to be:
average construction time = 5.5 years + (capacity × 2.0 years/GW)
The most common reactor capacity — as seen in the histogram at the top of the chart — is about 1 GW (=1000 MW). The linear regression tells us that the average construction time of such a reactor would be about 7.5 years.
So there we have it! A usual reactor takes about three-quarters of a decade to build. If we started right now in 2022, we could have new finished reactors by 2030.
There are some caveats, of course.
What we looked at is the construction time only — it does not take into account the excessive planning and approval phase prior to construction. If we were to want to start construction of new nuclear reactors now, we would also have to take into account this preliminary delay.
Furthermore, we are only considering the time it takes until the first grid connection. In general, this does not correspond necessarily to the time the reactor operates commercially at full capacity.
With proper maintenance, nuclear reactors can run for a long time — India’s Tarapur reactor blocks are running for about 52 years already, for instance. This mitigates the disadvantages the construction time brings with it somewhat (especially compared to renewable energy projects), but puts a serious obstacle in the way of the “explosive” nuclear reactor construction spree necessary to meet the 1.5°C goal with nuclear power alone.
Whether nuclear power can be considered renewable is another question. While sufficiently enriched uranium is somewhat limited, fast breeder reactors (like France’s Superphénix) in conjunction with reprocessing facilities (like France’s La Hague site) can overcome this limitation.
According to the IPCC report mentioned earlier, nuclear power will play a significant role in the energy transition. How big of a role it is capable of taking on, however, remains to be seen. ⬢
Tools: The infographic was created using Microsoft Excel and OriginLab for basic plotting and statistical analysis. I used Adobe Illustrator to pretty it up and add additional information. You are welcome to check out my other work on Behance.
Data: Reactor construction time and installed capacity is taken from the IAEA’s Nuclear Power Reactors in the World 2021 report. They provide helpful downloads for the raw data as well (“Supplementary Data”). The information of the individually highlighted reactors is taken from the corresponding Wikipedia pages.
