Over the past 80 years, nuclear power has gone from being the energy source of the future to one that has seen essentially stagnant growth over the past three decades. Since 1996, the only nuclear reactor to come online is the Tennessee Valley Authority Watts Bar Unit 2, which began operations in 2016. The opinions around nuclear energy have changed drastically since its beginning, with catastrophic failures such as Three Mile Island (U.S.), Chernobyl (U.S.S.R.), and Fukushima (Japan) making global news. However, for the United States, the slow of nuclear power growth cannot be attributed to the fear of failure. A shift in the economics of electrical energy has decreased national motivation to build and maintain nuclear plants as future sources of "clean" energy [1]. In the near future, the country will either need to overcome these hurdles to improve its aging nuclear fleet, or lean heavily on another source of energy to fill the gaps left behind by the die-out of nuclear.
So, how important is nuclear to the future of energy? In 2021, nuclear energy made up 18.9% of the electrical energy produced in the United States, equating to 778 billion kWh [2]. For reference, renewables produced 20% of the electrical energy consumed [2]. However, since 2000, renewable energy generation has grown 132%, and nuclear energy generation has stayed fairly consistent at around 790 billion kWh of production (peaking at 20.6% of US generation in 2001, and dipping to 18.9% in 2021) [2]. So, why is it that nuclear energy production has not grown with renewables, as the effort to de-carbonize the grid has increased?
One major issue with nuclear energy generation is the cost of the construction of a reactor. In a study of the average construction costs of different types of power plants, the construction of a nuclear facility was estimated to be around $5,148 per kWh [3]. The next highest cost was solar, at $2,921 per kWh [3]. However, since there has only been one nuclear plant constructed in the last two decades, the estimate is only based on an economic model conducted by EIA in 2018 [3]. The real costs of nuclear power plant construction could be much higher.
Another aspect that has hindered the growth of nuclear of the past decades is the amount of time required for construction, and the regulations that are in place. The first construction permit for the Watts Bar site was received by TVA in 1973 [4]. In 1985, with construction not yet complete on Watts Bar One, construction was delayed. Later that year, the Nuclear Regulatory Commission (NRC) completed an initial inspection of the reactor and allowed construction to continue [4]. However, Unit Two construction was delayed further. In 1996, 23 years after initial construction, Unit One was given a full power license by the NRC, allowing them to go online [4]. Unit Two, still stuck in the same stage of construction from 1985, was further delayed [4]. In 1999, TVA issued a request to push the completion date of Unit Two to 2010, which was granted [4]. In 2007, construction was resumed, and in 2016, Unit Two reached full commercial operation [4]. Overall, the project took 43 years to complete [4]. Any project developer would be apprehensive to take on a nuclear project after seeing that timeline.
The third issue with nuclear energy is actually calling it "clean" energy. It is not uncommon knowledge that the byproduct of a nuclear reactor is radioactive material. However, this not only refers to the uranium fuel pellets and "nuclear poison" rods used in the plant, but also to the tools and clothes used by workers that have come in contact with nuclear dust [5]. These can stay radioactive for thousands of years [5].
None of this would cause problems if the industry had developed an effective method for disposing of nuclear waste. However, this still poses many issues. Both low-level waste (LLW), which makes up about ~90% of radioactive waste, and high-level waste (HLW) need to decay underground for long periods of time after removal from the nuclear plant [6]. LLW can be stored in near-surface disposal sites (at or close below ground level for up to 30 years), but HLW requires more complex methods of disposal [6].
Currently, there is no active method for the disposal of HLW. Past the initial cooling and storage of the waste, there is no final management solution in operation [6]. Deep geological disposal, for periods of 50 years or more, is the plan that has gained the most traction in the nuclear community [6]. Sweden is expected to begin the operation of a mined repository, a type of deep geological disposal and the first of its kind, in 2023. In the Swedish plant, waste will be stored at depths of 250-1000m below the surface of the Earth, and left there to decay [6].
Now, that's a ton of issues. But, there's more. What happens to decommissioned nuclear plants?
The process of decommissioning a nuclear plant involves four things: decontaminating the facility, dismantling existing structures, removing contaminated materials, and storing nuclear waste until it can be removed for "disposal" [7]. Only after these tasks are complete can the area be released for other uses [7].
There are two methods used in the US to decommission nuclear plants: DECON and SAFSTOR [8]. In DECON, all nuclear waste is removed from the site, allowing for quicker reuse of the land [8]. This process takes at least 47 years [8]. The second method, SAFSTOR, is a much longer timeline, allowing for up to 50 years of the on-site containment of nuclear waste, followed by a 10-year decommissioning process [8]. This can be a more cost-effective process for a project owner since payment is spread over a much longer time than in DECON.
At the end of 2021, the US had 93 nuclear reactors still in operation, with an average age of 40 years [9]. In 2012, there were 104 reactors in operation [9]. With an aging fleet, declining reactor population, and limited enthusiasm to expand the industry, the US will need to act fast to fill the gap that nuclear will leave behind, a gap consistently making up around 20% of US electrical energy generation [2]. With technological improvements, nuclear power could once again see the same type of expansion that it experienced at the end of the 20th century. The question is, will the push to decarbonize the grid move too fast for nuclear technology to keep up?
Image: TVA Watts Bar Nuclear Facility
References
[1] Hsu, "Nuclear Power looks to Regain its Footing 10 Years After Fukushima," Scientific American, 9 Mar. 2021. https://www.scientificamerican.com/article/nuclear-power-looks-to-regain-its-footing-10-years-after-fukushima/#:~:text=%E2%80%9CThe%20decrease%20of%20U.S.%20nuclear,on%20the%20agency's%20Web%20site.
[2] "Energy Explained: Electricity in the United States," U.S. Energy Information Administration, 15 Jul. 2022. https://www.eia.gov/energyexplained/electricity/electricity-in-the-us.php
[3] Gerardi, "Power Plant Construction: How Much Does it Cost?" ProEst, 22 Feb. 2021. https://proest.com/construction/cost-estimates/power-plants/
[4] "History of Watts Bar Unit 2 Reactivation," United States Nuclear Regulatory Commission, 24 Mar. 2021. https://www.nrc.gov/info-finder/reactors/wb/watts-bar/history.html
[5] "Nuclear Energy," National Geographic. https://education.nationalgeographic.org/resource/nuclear-energy
[6] "Storage and Disposal of Nuclear Waste," World Nuclear Association, May 2021. https://world-nuclear.org/information-library/nuclear-fuel-cycle/nuclear-waste/storage-and-disposal-of-radioactive-waste.aspx#:~:text=Disposal%20of%20low%2Dlevel%20waste,the%20most%20radioactive%20waste%20produced.
[7] "Decommissioning Nuclear Power Plants," Nuclear Energy Information, Aug. 2016. https://www.nei.org/resources/fact-sheets/decommissioning-nuclear-power-plants#:~:text=The%20Decommissioning%20Process,-The%20companies%20that&text=Generally%2C%20sites%20must%20spend%20no,an%20extended%20period%20of%20time.
[8] "Decommissioning Nuclear Reactors is a Long-Term and Costly Process," U.S. Energy Information Administration, 17 Nov. 2017.https://www.eia.gov/todayinenergy/detail.php?id=33792
[9] "Nuclear Explained: US Nuclear Energy," U.S. Energy Information Administration, 18 Apr. 2022. https://www.eia.gov/energyexplained/nuclear/us-nuclear-industry.php#:~:text=At%20the%20end%20of%202021,commercial%20operation%20in%20December%201969.
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