Nuclear Power - Is our Fear Jeopardising our Future?

This is just a small post to share a video of a talk by Michael Shellengerger; an environmental policy expert who has dabbled in a large area of climate change topics from the planetary boundary hypothesis, to carbon pricing and beyond. This talk discusses how the impact of declining nuclear energy production is having a negative effect on our overall 'clean' energy productions, while also looking at the public's perception of nuclear, and the barriers this presents for the future of nuclear energy and climate change.

Michael's talk brings forward a number of thought provoking points, so if you would like to discuss any of them, please leave a comment down below.

Nuclear Fusion - The Future of Nuclear Energy?

A month or so ago I talked about ‘the science behind a nuclear power plant’ with a brief description of nuclear fission, which is the process of splitting an atom into two smaller atoms and is the way we harness nuclear energy for electricity at the moment. Today I’ll be talking about nuclear fusion, which is seen by some scientists as the way forward for nuclear power and part of the key to a greener future with near unlimited energy supply.

Nuclear fusion, in the way most people will know about it, is the process that powers the sun and ultimately is responsible for all life as we know it on this planet (ITER 2016). In the sun, hydrogen atoms are fused together a number of times to produce a helium atom, and it is this fusing of atoms that produces the energy.

Nuclear Fusion Process in the Sun (Wikipedia 2016)

However on Earth, things have to be done slightly differently; the nuclear fusion that occurs in the Sun begins at roughly 15 million °C, which is pretty hot as you’d imagine (FusionForEnergy 2015). Sadly on Earth, we don’t have it as easy. Due to the sheer size of the sun, it emits immense gravitational forces which produce intense pressure as well as a high heat which allow it to carry out its nuclear fusion (WNA 2016). On earth, we are not able to produce pressures on such a magnitude so we have to compensate for this by increasing the temperature input to around 50 million °C (WNA 2016). The most efficient and feasible reaction scientists are able to perform at the moment is a fusion of deuterium and tritium, which is essentially two different heavy forms (isotopes) of hydrogen (HyperPhysics 2016).  The tritium and deuterium are fused together and a helium atom is created, with a neutron as a by-product; it is this reaction that produces the energy. The aim is to get enough of these fusion reactions to occur continuously that the process will be self-sufficient, and more energy will be produced than is inputted. When this is achieved, nuclear fusion will produce 4 times the energy yield of fission, and for every time pressure within the reaction is doubled, the energy produced is increased four-fold (WNA 2016) (MIT News 2016).

D-T Nuclear Fusion Process on Earth (AtomicArchive 2015)

Now this is all sounds amazing, but there must be some reasons why we aren’t doing this right now; and there are quite a few as you’d imagine. First up is that extremely high temperature that is required to even begin the reaction. This is needed to overcome the electrostatic forces that act as a gateway to the fusion of the hydrogen atoms (WNA 2016). The issue isn’t creating the temperatures, but creating a device that could contain such a reaction for long periods of time. Without a long enough time period, the fusion reaction wouldn’t be able to be self-sufficient and have a net-energy output (WNA 2016). Secondly there is a slight issue of fuel; while the deuterium occurs naturally in seawater (the deuterium in a gallon of seawater has the energy equivalent of 300 gallons of gasoline), the tritium is a bit harder to come by (HyperPhysics 2016). The tritium has no sizeable natural source and due to its radioactivity, has a half-life of around 12 years, which means it has to be bred from lithium; this could possibly be a bottleneck in fuel supply (HyperPhysics 2016). Finally a big problem is the cost and scale it is going to take to research and finally produce a workable reactor. Initial costs of a fusion power plant are estimated to be around £10 billion, but the research for it is even higher, with ITER (International Thermonuclear Experimental Reactor) the centre of nuclear fusion experiments expecting to cost over €20 billion to even construct let alone run the experiments (EUROfusion 2016) (Bloomberg 2016). As fusion reactions are in a gas form compared to fission which occurs in a solid form, the energy released is less concentrated, so fusion reactors will be bigger and more costly to build and maintain (WNA 2016).

ITER Construction Site (Science 2015)

Other than the near unlimited energy that seems oh so far away, are there any other positives? Well, like nuclear fission they would only have a negligible contribution to greenhouse gas emissions if any and are seen as a way to help reduce our CO₂ emissions (WNA 2016). Unlike fission, fusion reactors are easily shutdown and it would be near impossible for a Chernobyl or Fukushima situation to occur (CCFE 2016). The issue of containing the reaction is also seeing positive results, with magnetic fields which hold the plasma where the reaction takes place being the preferred method (MIT News 2016). In terms of waste, no long-lived radioactive products are produced and any unburnt gas is dealt with on sight. There is the slight issue about the reactor structure itself becoming radioactive due to long-term bombardment of high-energy neutrons, but the radioactivity itself would be easily dealt with (WNA 2016). A big concern is a tritium release into the surrounding environment, however this is hoped to be dealt with by forgoing tritium altogether, and just fusing deuterium with deuterium instead (WNA 2016).

Nuclear Fusion Reactor with Magnetic Field (FusionForEnergy 2015)

Nuclear fusion is often seen as the finish line for nuclear energy, and part of the end game in reaching our planet's energy needs. With nuclear fusion experiments breaking previous records and devices containing the reaction for longer periods of time and at higher pressures being built, it seems we are edging closer to the goal (MIT News 2016). However, a long-running joke since the 70’s is that commercial nuclear fusion is always 40 years away, and as you can probably guess, is the latest estimate for now as well (CCFE 2016). Perhaps nuclear fusion is just one nut we’ll never be able to crack?

If you have any questions or are just curious about nuclear fusion, don’t hesitate to leave a comment down below and I’ll get back to you as quick as I can. 

Uranium Reserves – How much is there?

Uranium, as touched upon in a previous blog post, is the fuel used for nuclear fission and is primarily obtained through mining. As an element in the Earth’s crust, uranium is a relatively common metal on the scale of tin or zinc (Kidd 2011). Throughout the crust, uranium is found in different concentrations known as ppm (parts per million), which is how much of a certain rock is uranium. Rocks which have higher ppms will be given a higher grade and will therefore be more economically viable to exploit. The viability of the ore-body will also be dependent on the cost of energy produced from other sources, as a higher energy cost would in turn make more ore-bodies with lower ppms viable (WNA 2016).

Uranium can be found in various regions around the world, although are highly concentrated in certain places, with the top 5 countries having roughly 66% (OECD 2016) of known recoverable resources and just over 75% of Uranium output (Mining-Tech. 2014). The top dog in terms of uranium resources by far is Australia, with 29% of total known recoverable reserves, with Kazakhstan, Canada and Russia each having a respectable 13-9% each (WNA 2016). This spread of uranium reserves across the global and political landscape would mean it would be hard to truly blockade a country from accessing uranium to feed its nuclear intent.

Global distribution of Uranium in the top 15 countries  (OECD 2016)

Uranium per Country with Cost (WNA 2016)

The big questions are how much uranium is there? And how long will the uranium last? This is mainly measured from the price of extracting said uranium, as some ore-bodies will cost more to extract. At a price of USD 130/kg and less, there is predicted to be 5.7 million tons of identified uranium that can be mined (OECD 2016), which if matched up with the 2006 uranium requirements of 66,500 tons, which would last roughly 85 years (Chmielewski 2008). Different sources using slightly different values calculate 80 years and 90 years of Uranium supply left at this price (Kidd 2011) (WNA 2016). These calculations are based on a scenario that nuclear energy doesn't really change going into the future, and a whole range of different scenarios could increase or decrease viable reserves. A decrease would only likely come about if the overall cost of producing energy decreased to a point, that nuclear energy was being priced out by other energy sources. If prices dropped to a point where only uranium mined at a price of USD 80/kg or less was viable, then only 37% of the 5.7 million tons mentioned earlier, would be able to be mined (OECD 2016). Increases of viable reserves could be caused by a number of things; simply an increase in the price of energy would allow more orebodies to be mined that were once too expensive. Discovery of further uranium resources from geological predictions will of course increase supply, with (Chmielewski 2008) estimating that we would have enough Uranium to last 300 years. Recycling plutonium from spent fuel cells could increase the life of today’s known uranium supply by 70 times, which would mean the reserves could last up 3000 years! Technological advances also have the capability to reduce mining costs and extend the life of fuel cells, with the new Generation-IV fast neutron reactors with their closed fuel cycle producing 100 times the energy with the same quantity of uranium (Chmielewski 2008). All these factors have the potential to come together, to give us the uranium we need for thousands of years.

Worldwide uranium resources and potential years of generation (Chmielewski 2008)

Uranium resources have been increasing significantly since 1975 in correspondence to increased expenditure on exploration. This would suggest that as exploration increases, viable reserves of uranium would also increase, with previously uneconomic uranium from Florida once again being examined for possible extraction, and lower-grade ore bodies such as those in Morocco also being investigated (Kidd 2011). This is because, the uranium fuel only makes up a fraction of the cost of nuclear energy; only 2% of the cost is attributed to the uranium, with the vast majority attributed to building the plant, operating and maintenance. This means that a theoretical doubling of uranium prices would only add a 2% increase on to final electricity bills (Chmielewski 2008).

Known Uranium Resources, their prices and Exploration Expenditure (WNA 2016)

As technology advances and additional orebodies become viable and are discovered, it appears that reserves of uranium will be around for thousands of years to come if managed correctly. This could pave the way to an era of cleaner energy if managed correctly. This is dependent on the research and exploration being done however, which may be at risk from investment as recent discoveries of cheap shale have the potential to side-track nations away from uranium exploration. Or there is the potential that uranium may not be needed at all by 2050, with hopeful estimates that we could have nuclear fusion power plants in operation by then!