Nuclear Fission Energy: Overcoming Demons to Help Solve Climate

By: Arnaud Paquet

Gigaton Potential

Nuclear energy generated more than half of the U.S. carbon-free electricity in 2021, according to the IEA (International Energy Agency). Over the past 50 years, nuclear has saved our atmosphere from more than 60 gigatons of CO2 emissions that would have otherwise come from fossil fuels. The IPCC found that global nuclear capacity would need to triple, reaching 1160 GW of electricity by 2050, to achieve our climate ambitions. This alone could save 5 gigatons of CO2 annually.

For reference: in 2019, the world emitted 51 gigatons of CO2-equivalent greenhouse gases. Project Drawdown estimates we need to cumulatively eliminate 1,000 GT from 2020-2050 to keep global warming below 2 degrees Celsius.

What You Should Know

As population grows, living standards improve, and electrification accelerates (e.g., through increased adoption of heat pumps and EVs), the world needs clean, abundant, and cheap electricity.

Nuclear power is attractive because it does not emit CO2 and is independent of meteorological factors, unlike wind or solar energy. Hence it does not require storage capacities to be reliable and has a high capacity factor (~90%). It also produces much more energy than other sources on a given land area.

Yet, the West is observing a decline in nuclear capacity. The nuclear fleet in advanced economies is ageing and 25% of existing reactors are expected to be shut down by 2025. With this status quo, the energy transition in advanced economies will require an additional $1.6 trillion of investment over the next two decades. As nuclear reactors retire, gas-fired power plants will play an even more central role. Every new gas capacity built now will most likely remain in the energy landscape beyond 2050, the target date for carbon neutrality.

Why are we observing this nuclear fade case? Three demons, three reasons: waste, safety, and cost.

Nuclear waste encompasses different categories, but the most radioactive waste is spent fuel that is recovered from the reactor core. Spent fuel must be stored safely (e.g., underground) for 300,000 years before getting back to natural radioactivity levels. However, on this time scale, there can be no certainty that required information will be properly transmitted through generations. A solution would be to burn the spent fuel with a new type of reactor using fast neutrons.

Nuclear energy is haunted by the Chernobyl and Fukushima accidents. Those events have told us that the nuclear risk exists, but must also teach us to put it in perspective with the climate risk. Chernobyl’s reactor was a RBMK design, which was inherently unstable and is no longer operated in the West today. The Fukushima nuclear accident did not cause any adverse effects on the health of Fukushima inhabitants, according to a 2021 United Nations report. Meanwhile, fossil fuels are responsible for the deaths of 7M people worldwide every year, according to WHO. Our World in Data has compared the death rate of energy sources, and nuclear is the second safest, after solar energy.

The nuclear industry has a recent history of construction delays and cost overruns. In the U.S., the Vogtle nuclear power plant’s two new reactors are seven years behind schedule and $16 billion over budget. While utilities hope to accelerate their learning curve, there is a valid argument against large reactors because of their intrinsic complexity. For this reason, the industry has recently been bullish on Small Modular Reactors (SMRs).

Another solution to lower the cost of nuclear and electricity in general is to extend the lifetime of existing reactors. Most nuclear reactors can operate safely beyond their designed lifespan of 40 years. With plants already depreciated, lifetime extension offers CO2-saving opportunities at extremely low cost compared to new build, making nuclear cheaper than renewables. Inexpensive nuclear energy can also be used to power the hydrogen economy. DOE estimated that a 1-GWe reactor could produce up to 150,000 tons of clean hydrogen per year. In addition to cost benefits, lifetime extension will allow the industry to maintain know-how while developing new advanced nuclear technologies.

A recent example is Diablo Canyon, California’s last operating nuclear power plant, which has received federal funding for life extension. But such examples are rare. U.S. utilities are incentivized to retire their assets when fully depreciated, which is the exact opposite of what should be done. This is the Averch-Johnson effect, and new regulations are needed to remove these inefficient incentives.

Opportunities for Innovation

Small Modular Reactors (SMRs) bring innovative answers to crucial questions. Their small size (10-300 MWe; large reactors are usually > 1 GWe) reduces upfront capital requirements and lowers investment risk profiles. Smaller size also enables close integration to industrial sites with intensive energy demand (e.g., the Dow and X-Energy partnership). Because SMR designs come with a variety of sizes and technologies, they are particularly suited to produce carbon-free process heat. In 2021, 90% of the heat was still generated by fossil fuels.

Historically, nuclear reactors have always been built bigger and bigger for economies of scale. The paradigm has changed, and that’s where modularity comes in. SMR components (modules) are intended to be standardized and built in a factory, rather than on site in case of large reactors. This would theoretically reduce construction costs and time and accelerate learning curve. SMRs are trying to replicate what allowed an 80% drop in solar PV costs over the last decade. Thanks to their modularity and load-balancing capabilities, SMRs can step in or step back, whether renewables generation is low or high. In this carbon-free scenario, nuclear energy accelerates the deployment of renewables by compensating for their intermittent nature. For this reason, electricity markets must properly reward dispatchability, i.e., the grid services needed to maintain security of supply.

SMR companies show great promise, but have yet to prove they can deliver on time and on budget. NuScale Power, a long-time leader in SMRs, has seen its construction cost estimates rise due to inflation and supply chain issues.

NuScale VOYGR™ SMR power plant. Source: NuScale Power.

Generation IV reactors may be the ultimate answer to nuclear waste. Gen IV encompasses six different reactor technologies, one of which is being developed in my home country, Belgium. MYRRHA is a lead-cooled fast reactor project, which uses fast neutrons (as opposed to thermal neutrons for today’s reactors) to address the problem of waste radiotoxicity. By transmuting minor actinides in the spent fuel, this advanced technology could reduce the required storage time from 300,000 to 300 years – much more realistic and manageable on a human timescale – and the volume of high level radioactive waste by 99%.

A 3-D render of the full MYRRHA facility. Source: MYRRHA, SCK CEN.       

Conclusion

This vision of an energy mix made of renewable and nuclear energy is shared by many trusted international organizations, such as the IPCC and IEA. Support for nuclear power may come from an honest observation: renewables are a cornerstone of the energy transition, yet on their own they will not be sufficient to decarbonize the whole economy in time.

Author Bio

Arnaud Paquet is an MBA candidate at UC Berkeley, with years of experience in the clean energy sector. His passion lies at the intersection of energy transition and social impact, and he is interested in learning more about how to decarbonize the hard-to-abate sectors. Arnaud also has a secret admiration for heat pumps!