February 2, 2018 Nuclear Energy Written by Sara Slavikova
Is nuclear power renewable
The United States, France, Russia,

South Korea and China, as diverse as these countries are, share one common characteristic. They are the top nuclear power producers in the world and they lead the efforts to convince everyone that this technology is clean and renewable [1]. This would enable them to access some of the benefits (like governmental subsidies) allocated to the expansion of renewable energy.

The idea stems from the extremely low greenhouse gas emissions released during the process of energy generation. Indeed, when talking emission-wise, this characteristic brings nuclear power much closer to solar, wind, geothermal or hydropower – renewable sources that emit just a fraction of carbon emissions compared to the fossil fuel industry. In fact, nuclear power emits between 10 to 130 grams of carbon dioxide per kilowatt hour of generated power. A similar amount is released by one of the lowest emitters – wind energy.

But there is one major problem with this concept – we should not assess renewability of resources based on the amount of emissions they release but on their capacity to naturally renew.

So, into which category does nuclear power really belong despite the pro-active lobbying of the nuclear industry?

Let’s start right from the core to determine the answer.
 

How is nuclear energy produced?

Nuclear power is released in the process of nuclear fission. This process basically breaks bonds which hold together the core of an atom.

Each atom has a core, also called nucleus, which consists of protons with a positive electrical charge and neutrons without any charge. Protons and neutrons in the core are drawn together by a strong nuclear force.

It is hard to imagine, but this force is actually multiple times stronger than gravity [2]. However, even such a strong bond is not unbreakable. Under the right conditions (for example inside the nuclear reactors), bonds in the core can be disrupted, releasing enormous amount of energy.

A nuclear power plant with four working reactors

A nuclear power plant with four working reactors


 

What happens to uranium during nuclear fission? 

Uranium is the most common nuclear fuel. When a large atom of uranium undergoes nuclear fission, two neutrons are separated from the core along with the energy. At the same time, the core itself splits into two fission byproducts with smaller cores. These elements are not always the same, but share two common characteristics – they are highly unstable and radioactive.

The two neutrons released together with the energy, quickly hit other uranium atoms, which split and the whole process repeats again for as long as more fissile uranium atoms are present in the reactor [3].

Based on this information you might already guess the answer about the renewability of the nuclear power. Despite the arguments of the nuclear proponents about low emissions and higher efficiency, this form of energy is non-renewable.
 

Why is nuclear power non-renewable?

To create nuclear fission, heavy fissile element like uranium is needed. Even though, uranium is a common metal on our planet, it is still a non-renewable source.

Nuclear power plants use as a fuel only one isotope of uranium, known as uranium-235 (U-235).  It is because its atoms are easily split apart. The problem is that in nature, this isotope represents only 0.7 percent of uranium. The remaining 99.3 percent of uranium are present as an isotope uranium-238 (U-238), which cannot be used for nuclear fuel [4].

To get suitable quantities of U-235 for the nuclear fuel, extracted uranium ore has to go through a milling process to separate uranium from the ore. Once the milling is completed, uranium must be enriched to have the composition needed to fuel nuclear reactors.

At the moment, identified uranium resources amount to a total of 5.5 million metric tons, while it is estimated that an additional 10.5 million metric tons remain undiscovered [5]. Given today’s consumption rate where nuclear energy makes about 11% of all energy sources worldwide, this means we have roughly a 230-year supply of uranium [6].
 

The theory of breeder reactors or turning uranium fuel into a renewable resource

Professor Bernard Leonard Cohen published in 1983 a scientific paper, where he claims that we have at our disposal enough uranium to last for the lifetime of our solar system. With this statement, he pronounced nuclear power a renewable source of energy in the same context as the solar energy is. Once the Sun ceases to exist, our planet will die too, and we will not be bothered by the renewability aspect of our resources anymore.

Professor Cohen’s theory combines two thoughts. The first thought is the use of nuclear fission in breeder reactors. Breeder reactors are 100 percent more efficient than traditional nuclear reactors, because they generate new fuel during the process of fission. The chain reaction can, therefore, continue much longer, releasing more energy [9].

The second thought is the extraction of uranium from seawater. According to his calculation, seawater contains 3.3 parts per billion of uranium and could approximately supply energy for the next seven million years.

Sea waves hitting the shore

Sea waves hitting the shore

When reading such positive convictions, our level of enthusiasm might rise and say “Nuclear power is renewable after all.” But at the same time, we have to ask why this strategy hasn’t been applied since 1980s, if the world had such a great solution at hand.

The answer is the best expressed in the report of the International Panel on Fissile Materials from 2010: after 60 years of testing, breeder reactors come with serious problems, ranging from the safety issues, higher proliferation risks, lengthy repair time and high costs to operate.

Unfortunately, all these issues together represent a too big challenge for this technology to be effective for our purpose at the moment [10].
 

The environmental impact of nuclear power

Nuclear energy is therefore not only a non-renewable form of energy since uranium stocks will be depleted in the foreseeable future, leaving us locked with a technology that can no longer be used, but extraction of the raw materials required to kick-start the process results in a number of environmental concerns.

More specifically, one reactor needs in one year 25 tons of uranium fuel. The process of extraction and milling of this fuel leaves behind 500,000 tons of excavated material and 100,000 tons of highly toxic mill tailings. These tailings contain a variety of radioactive elements such as thorium, radium, and polonium, together with heavy metals and arsenic [7]. And for sure you don’t want to be anywhere close to them.

Even more concerning is the fact that the amount of tailing sludge left behind equals the amount of the gained uranium ore, and also contains 85 percent of the initial radioactivity.

The decay of radium continuously emits into the atmosphere radioactive gas radon-222, known to cause lung cancer to those breathing this gas for longer periods of time [8].

And when it comes to radioactive substances, the time can surely be very long… More precisely, radium’s half-life is 1,600 years.
 

To sum up

Even the process of nuclear fuel extraction is hazardous for the environment and our health. In other words, while nuclear energy offers distinct benefits over other non-renewable energy sources such as fossil fuels, we would be remiss to forget that nuclear power is also a form of non-renewable energy, which comes with several drawbacks in terms of extraction, use and disposal of radioactive waste.

 


References

[1] http://www.eia.gov/energyexplained/index.cfm/index.cfm?page=nuclear_home
[2] https://simple.wikipedia.org/wiki/Strong_interaction
[3] https://en.wikipedia.org/wiki/Nuclear_fission
[4] https://goo.gl/keQrcz
[5] https://goo.gl/XTje76
[6] https://www.nei.org/Knowledge-Center/Nuclear-Statistics/World-Statistics
[7] https://www.theguardian.com/commentisfree/2008/dec/05/nuclear-greenpolitics
[8] http://www.wise-uranium.org/uwai.html
[9] https://en.wikipedia.org/wiki/Breeder_reactor
[10] http://fissilematerials.org/blog/2010/02/history_and_status_of_fas.html