Diving into Nuclear Energy

A couple of months ago I stumbled across a TED talk by Michael Shellenberger where he explained why he has changed his opinion about nuclear energy. That made me want to learn about this controversial topic.

Belgium, Germany, Spain and Switzerland have planned nuclear phase-outs by 2030. By contrast, the electricity generated by nuclear power plants is 75% in France, around 20% in the USA, 26% in South Korea and 30% in Japan. According to Our World in Data, nuclear energy is one of the cleanest, safest and efficient energy methods with one of the lowest death rates due to accidents and air pollution. Then why is it being phased-out in so many countries?

I spent the last few weeks trying to understand the reasons behind this controversy and how the future holds for this sector.

Firstly, I think it is important to define what nuclear energy is. What is the most efficient energy source? What are the advantages and disadvantages of nuclear energy compared to renewables? And what about the generated waste? I tried to answer these questions and it was not an easy task. I found it particularly difficult to find unbiased information about this matter. It seems that if you are pro-renewables, you are automatically against nuclear power, and the same the other way around... We can easily understand that it is in fact a very controversial topic. Let 's dive in!

What is nuclear energy?

Nuclear energy is the energy obtained from nuclear fission or nuclear fusion, the latter being the source of energy that powers stars. In nuclear fission, a neutron collides with a uranium atom and splits it, this split generates energy which is used to heat water and generate steam which in turn spins turbines to generate power. Every atomic fission emits new neutrons which will trigger new fissions and so forth. This multiplying effect is called a nuclear chain reaction. This reaction is controlled in a reactor to produce the desired amount of heat. Most nuclear power plants use uranium atoms, though plutonium atoms can also be used.

FUEL - A nonrenewable resource

Uranium is not a renewable resource. Is this an argument against nuclear energy?

One of the arguments used against nuclear energy is the fact that Uranium is not a renewable source. Uranium demand is driven by the number of operating reactors, which ultimately is driven by the demand for electricity. According to the report "Uranium 2020, Resources, Production and Demand", from the Nuclear Energy Agency, there is sufficient uranium resources to support continued use of nuclear power and significant growth in nuclear capacity for electricity generation, for over 135 years considering uranium requirements of about 59 200 tU (data as of 1 January 2019). Also, further exploration and improvements in extraction technology are likely to at least double this estimate over time. Furthermore, with Breeder reactors (nuclear reactors that generate more fissile material than what they consume) we could get the maximum use of the Uranium resources on Earth which can last thousands of years. This requires advances in seawater uranium extraction, reactor construction performance, and public acceptance. Breeder reactors have been developed in the past, but they remain a small minority of our current fleet. This topic deserves its own article because although 135 years of uranium supplies do not look sustainable, this shouldn’t be enough to exclude nuclear energy given the potential for this timeframe to be extended by technologies such as breeder reactors.

EFFICIENCY

What is the most efficient way of producing energy?

The Nuclear Energy Institute reported that one uranium fuel pellet (about the size of a gummy bear) creates as much energy as one ton of coal, 149 gallons of oil or 17,000 cubic feet of natural gas. To put this in perspective, five grams of a tiny pellet can produce enough energy to power a normal household for 6 months. A single nuclear power reactor generates enough electricity on average to power 755,000 homes without emitting any greenhouse gases.

Furthermore, The Department of Energy in Washington shared some interesting facts. One nuclear power plant produces around 1 gigawatt of power per plant on average. In order to produce the same amount of energy, we would have to build 3.125 million PV panels (based on the average silicon model panel size of 320 watts) or 431 utility-scale wind turbines (based on the average utility-scale wind turbine size of 2.32 MW installed in 2017).

Also, as we can see from the image below, nuclear energy has by far the highest capacity factor of any other energy source, which also speaks about its better efficiency.

*Capacity factor by Energy Source in 2020

Is nuclear energy a clean source of energy?

According to the Intergovernmental Panel on Climate Change (the United Nations’ body for assessing the science related to climate change), Nuclear power plants produce no greenhouse gas emissions, and over the course of their life-cycle, they produce about the same amount of carbon dioxide-equivalent emissions per unit of electricity as wind, and one-third when compared with solar.

Average life-cycle carbon dioxide-equivalent emissions for different electricity generators (Source: IPCC) *A lifecycle approach includes: emissions from all phases of the project (construction, operation, and decommissioning).

SAFETY

If nuclear energy is the most efficient and one of the cleanest sources of energy, why isn't it an obvious choice?

One of the first things most people think of when they hear about nuclear power plants is the disaster at Chernobyl (1986) and Fukushima (2011). Even though the potential risks of nuclear energy are real, the data shows it as the 4th safest energy source as we can see in the graph below.

The death rate associated with nuclear power includes the estimated 4000 Chernobyl deaths (WHO data) and 574 deaths from Fukushima (one worker death, and 573 indirect deaths from the stress of evacuation). The remaining are occupational deaths largely from mining and milling.

By contrast, the worst accident of all time in the energy sector was the 1975 collapse of the Banqiao hydroelectric dam in China. It collapsed and killed between 170,000 and 230,000 people.

However there is still a big stigma and misinformation around this topic which discourages the growth of this field which might be the best answer to our energy needs. Not to mention that any modern nuclear power plant is orders of magnitude safer than Chernobyl was. Furthermore, a Chernobyl-type accident could not have happened outside of the Soviet Union because this type of reactor was never built or operated in the West. The known fatalities during the Chernobyl accident were mostly emergency first responders. Newer generations of nuclear reactors, particularly what is called pebble-bed reactors, are designed so that the nuclear chain reaction cannot run away and cause a meltdown - even in the event of complete failure of the reactor’s machinery.

The Chernobyl disaster was a unique event and the only accident in the history of commercial nuclear power where radiation-related fatalities occurred. Moreover, Fukushima and Chernobyl are the only major accidents to have occurred in over 18,500 cumulative reactor-years of commercial nuclear power operation in 36 countries.

RADIATION

There is also a fear associated with the impacts of the radiation on humans and wildlife. Coal, oil, natural gas, and biomass energy production have killed 100 million people in the last 50 years. This is mostly due to pollution generated by burning fossil fuels. The World Health Organization explains that it is safer to work in a nuclear power plant than in a big city office as the urban air pollution of ozone, sulfur dioxide, carbon monoxide and nitrogen dioxide causes 7 million deaths annually. Only 0.005% of the average American's yearly radiation dose comes from nuclear power. This is 200 times less than a cross-country flight, and about the same as eating 1 banana per year.

WASTE - Nuclear and Renewables

Nuclear energy produces radioactive waste that must be securely stored. Storage of radioactive waste is a major challenge facing nuclear power plants. Sincethere’s no way to destroy nuclear waste, the current solution is to seal it securely in containers and store it deep underground where it can’t contaminate the environment. The solutions developed to store the nuclear waste were designed to prevent any movement of any radioactivity for thousands of years. So even in the case of an earthquake or other natural disaster, the repositories will keep the waste from reaching the surface and release radiation.

Does the transport of this waste pose a risk to people and the environment?

Hazardous waste is produced by most major industrial processes. Of all hazardous material shipped each year in the USA, radioactive waste accounts for just 5% of the total; and of that 5%, less than 10% relates to nuclear power production. Again, we have to put this in perspective. At least 25,000 shipments of HLW (high level waste) have been made worldwide, covering many millions of kilometres on land and sea. There has been no instance of radioactive release causing harm to people, property or the environment in many millions of transport miles.

The IAEA estimates that 370,000 tonnes of heavy metal (tHM) in the form of used fuel have been discharged from all nuclear power plants worldwide since they started being used in energy production in 1954 through the end of 2013. The agency also estimates that the disposal volume of the current solid HLW (high level waste) inventory is approximately 22,000m3. For us to better understand what this means, this is roughly the volume equivalent to a three metre tall building covering an area the size of a soccer pitch.

Now, regarding renewable energy, it is solar panels that have a particular problem. There is growing evidence that broken panels release toxic pollutants. The International Renewable Energy Agency (IRENA) estimates that solar panels produced 250,000 metrictonnes of waste in 2018 alone.

Most solar panels have lifespans of at most 30 years. Panels installed today will need disposal around 2050. According to the EPA briefing, by 2050 the United States will have 10 million tons of solar waste, China 20 million, India 7.5 million, Japan 7.5 million, and Germany4.3 million.

Regarding wind, the University of Cambridge estimates wind turbine blades will generate 43 million tonnes of waste by 2050. While the majority of wind turbine components can be recycled, particularly steel and copper wires, the fibreglass blades can’t.

Investment

The biggest challenge concerning nuclear power plants may be the costs involved. According to a two-year study from MIT students examining the future of nuclear energy in the U.S. and western Europe, building new nuclear plants isn't a profitable investment.

It´s true that the capital cost of building these plants is too high, but one thing that is almost never considered is the distributed costs over the lifespan of the technology which according to the video “The Economics of Nuclear Energy”, tend to be low compared to the long term profit that they generate.

Future research, development, and demonstration (RD&D) funding should prioritize reactor designs that optimize costs, including construction costs.

Forecasts

Worldwide, nuclear power could be a significant player in the coming decades. China, the largest greenhouse gas emitter, increased its nuclear output 6% in 2020 and currently has 17 new reactors under construction, according to the World Nuclear Association.

Deployment of advanced reactors and fuel cycle technologies could also significantly contribute to the world’s energy supply in the long term. As technology improves, we will hopefully find better ways of storing radioactive waste.

In addition to this, thorium, which is more abundant than uranium in the earth’s crust, is also a potential source of nuclear fuel if alternative fuel cycles are developed and successfully introduced in a cost-effective manner.

Regarding solar and wind, it seems that without a strategy for their end-of-life management, solar panels, electric vehicle batteries, and windmills will place an unintended burden on our planet and economy.

After everything I’ve learned, I would say that the best option for a low-carbon and reliable future would be having a share of nuclear power, a share of renewables and energy storage. Solar and wind are still very good alternatives and essential to achieve a zero-carbon future, but that is a topic that I will address in another article.

I found the arguments on both sides much more complex than what I have written here. This article was based solely and exclusively on my genuine interest in better understanding the controversy behind nuclear energy.