Rivers flowing with nuclear waste!

Not all nuclear energy and waste that is produced is stored carefully - some can also find it's way into rivers and lakes which can have disastrous effects. Despite the London Convention, which was signed in order to prohibit the disposal of radioactive substances in rivers during 1972, developed countries have still failed to stop the leaking or dumping of waste in rivers (Melosi 2009). This historical problem, despite it's consequences, has not been given enough attention as the focus is much more on nuclear waste leaking underground (Plato 1974). Well, I think it should be given more attention! Nuclear reactors regularly emit liquid radioactivity which contains isotopes such as Cesium 137 and Strontium 89. Normally this liquid radiation is stored and taken care of, however many times it has leaked which has led to severe health complications. In her study in South Korea, Lee et al. (2015) explains how radioactive isotopes such as Strontium 89 (which has a half life of 30 years) have been known to spread throughout the body which has led to a reduced sperm count and organ failure in many cases.  Let me show you a real life example where nuclear waste in a river has led to severe consequences...

Hanford Site in Columbia River


The Hanford Site on the Columbia River, which has now been decommissioned, was established in 1943 and was the world's first plutonium production reactor. It has been declared as 'the largest nuclear clean-up site in the Western Hemisphere' according to the Times. Decommissioned in the 1960s, the plant left around 53 million US gallons of radioactive material which had been stored in nuclear tanks and eventually this leaked in 1962 which led to around 0.6-1.5 million gallons of toxic material such as Cesium 137 and nitrates being released into the Columbia River. Water sediments taken by Fredrickson et al. (2004) have shown an increase in river temperature due to the presence of radioactive material which is still present today. The exact cause of this leak has still not been discovered, however the main explanation is that the carbon steel shells which stored the material had cracked which led to the escape of the radioactive liquid.

Selection of pictures taken in 2012 showing the cracks in the carbon steel shells 

Although clean up of the plant and the nearby river started in 1988, construction companies such as Bechtel have been given government contracts to develop water treatment plants amounting to over $12.2 billion. The total cost to treat the area has been reported to have reached $40 billion and further leaks were reported in 2013. Imagine where else that money could have been used! The ecological effects of this disaster are still ongoing as low radioactive concentrations of Plutonium-238 have been reported in the nearby fish and aquatic wildlife which the Native American population relies on (Delistraty et al. 2010).  The sad fact however is that Hanford is not the only place which has seen this disaster. Lake Karachay in Central Russia was used as a dumping ground for radioactive waste during the Cold War. According to 1990 figures, just standing by the lake edge for a few minutes could have given you a dose of around 600 roentgen which could have been enough to kill someone. This shows how crucial it is to have the constant maintenance of nuclear disposal sites to ensure that there are no leaks in the future. Not only that, but I believe that international sanctions and rules should be strengthened to ensure that any negligence or carelessness is dealt with accordingly. After all, these incidents have an impact on generations to come.

Lake Karachay has become more toxic over time 

USA's radioactive waste problem

Last week I spoke about how managing nuclear waste, both above and below ground is a key economic, social and safety challenge. A country which epitomises this challenge is the USA, a country which I will focus on in more detail. Most striking is the fact that 1 out of 3 Americans live within 50 miles of a nuclear waste site and this figure is set to increase as more waste is produced. Finding space for this nuclear waste is also a problem and this is compounded by the fact that there are risks that terrorist might try and target nuclear reactors and disposal sites in the aftermath of 9/11. This poses a key problem for the US government and especially the Department of Energy who have so far failed to create a comprehensive strategy to deal with nuclear waste disposal according to the Nuclear Energy Institute.

Rising nuclear waste in America 

Yucca Mountain nuclear waste repository: a failed project

The Yucca Mountain nuclear waste project is a typical example of how politicised nuclear waste can actually become. Through the Nuclear Waste Policy Act (1987), the Yucca Mountain in Nevada was designated as a deep geological storage facility where around 70,000 metric tons could be stored. In 2002, President George Bush recommended the site to be constructed however problems started to emerge straight afterwards. Many of the governments own reports, one from the Nuclear Waste Technical Review Board, reported that there was 'limited confidence in current performance estimates'. There were many other conflicting reports that were published by the government, some supporting the proposal and some suggesting that the site was not geologically safe to be built upon. Funding has since stopped for the project as the Obama administration reported that it was not a attractive solution for storing nuclear waste according to the New York Times in 2011. Amid these political difficulties, Ewing and Macfarlane (2002) effectively summarise that long term implications for the project were not looked at in terms of it's cost and long term maintenance. However, I would like to argue that the main reason why this project failed was because of the behind the scenes lobbying work carried out by the local Western Shoshone people who opposed the project - academic literature has largely ignored their efforts. Have a look at this short documentary called 'An Act of Genocide: The Fight to Save Yucca Mountain' which shows how the local people fought against these proposals through their demonstrations and political lobbying:

Toxic waste removal

Last week I spoke about how nuclear power is actually produced through the process of nuclear fission. Although it is a very interesting process scientifically, there are some major challenges that arise after nuclear energy has been created - nuclear waste. At every stage of the nuclear fuel cycle, nuclear waste is produced, either through the process of uranium mining or through the reprocessing of the fuel that is left over. In fact, according to Greenpeace, the level of spent nuclear fuel is increasing by around 10,000 tonnes annually. Not only that, but unlike our normal household rubbish, this nuclear waste cannot be dumped in a bin but has to be stored carefully due to it's radioactive nature which I will explain later.

According to the United States Nuclear Regulatory Commission (USNRC), there are two types of nuclear waste - high level and low level waste. Low level waste is any item that has been used during the process to create nuclear energy and has been exposed to some form of radiation. That includes everything from mops, medical tubes, equipment and even the clothes that have been worn by staff working in nuclear power plants. High level waste, however, is the spent fuel that has been used during the nuclear fission process. That is where the concern lies. During the process of nuclear fission, transuranic elements are produced. Although these elements do not produce enough heat energy, they take longer to decay and account for a large majority of the radioactive waste that decays over a period of around 1,000 years according to Molecke's 1980 study. Some of the radioactive isotopes in these elements decay within minutes, however some of the elements take quite long to decay - for example Plutonium-239 has a half life of over 24,000. The safe storage of these radioactive elements is a major concern for scientists and governments across the world. Most recently, writing for the American Geophysical Union, Colgan et al. (2016) reported that nuclear waste which has been buried under the Greenland ice during the Cold War period might be released due to rising global warming which is melting the ice layers. The study concluded by saying that this radioactive material might even be released into oceans by the end of the century - yikes! If you think that this is another doomsday scenario by an expert then you are completely WRONG. A radiation leak worth £240m occurred during March 2015 at the Waste Isolation Pilot Plant in New Mexico, US which sent shockwaves through the scientific community. There are many other nuclear waste leak examples, some of which I will mention later in my blog, however let's have a look at some of the ways in which radioactive waste is stored.


How is radioactive waste stored?

One of the main ways in which nuclear waste is stored is through underground repositories where radioactive material is held in canisters or tankers for hundreds of years. An interesting example is the Oilkiuoto repository on the west coast of Finland which is currently being constructed. This 3 billion euro underground facility, as Gibney (2015) reports in 'Nature', will start storing nuclear waste by 2023.

Oilkiuoto underground repository under construction

The main problem, however is public opposition against such large nuclear disposal sites and this poses a key challenge for governments as they try to find new disposal sites. Earlier in 2013, there were plans to build a nuclear disposal facility in West Cumbria near the Lake District however these plans were scrapped because of public opposition. For a minute have a think. Would you want a nuclear disposal site close to your house? Well, I guess the answer would probably be NO. 

Secondly, low-level nuclear waste (which I mentioned earlier) is usually stored overground as it is deemed to be safer in terms of radioactivity. This again presents new problems for engineers, governments and scientists. If radioactive waste is stored overground, there is a heightened risk of corrosion due to air humidity levels (Larsen 2015). Air humidity levels need to be controlled to allow the easy ventilation of air to avoid any corrosion and the cost of keeping these facilities is substantial as this type of low-level waste could stay radioactive for over 25 years. Complex computer generated simulations, as the image below shows, need to be analysed to monitor air ventilation. In a nutshell, nuclear waste poses key challenges for society, both above and below the ground. This can be in financial terms through constant maintenance and even social terms through public opposition and safety risks. 

Simulations showing the circulation of air flow around a nuclear storage facility

How is nuclear power produced?

Before we start the discussion on whether nuclear energy can have a positive or negative impact on our energy needs, it is very important to actually understand how nuclear power is produced. According to research conducted by the Nuclear Energy Institute, 30 countries around the world have operational nuclear reactors (around 450 in total) and over 60 are currently under construction. Not only that, but nuclear energy provides around 12% of the world's electricity according to a worldwide study conducted by Mycle Schneider and his colleagues for the World Nuclear Industry Report 2016. For many countries nuclear energy contributes towards a large chunk of electricity consumption, whereas for others it is not that substantial - 75% of France's electricity is generated through nuclear power but for India the figure is only 2% (see the figure below).

  Nuclear power production worldwide 

Often our understanding of nuclear energy is shaped by what we see in the media and through popular culture e.g. Hollywood films and TV adverts (Gamson and Modigliani 1989). We all remember cartoons like Dexter's Laboratory which showed how nuclear energy is made by a touch of a button or Marvel films which show bubbling cylinders of Uranium.  Whether we realise it or not, such representations have given many people (including myself before this blog) a very simplistic view of what nuclear energy is and how it is produced. Let's change that!

How is nuclear energy produced?

The crucial element in producing nuclear power is uranium. A silvery-white metal ore, uranium is a radioactive substance which is mined underground and is predominantly found in parts of Australia, Kazakhstan and Russia. The key advantage of using uranium is that it is quite abundant across the world, unlike coal and oil reserves which are seen to be dwindling in volume. In fact, a study by Smith (2006) has shown that are around 10 million tonnes of uranium which are classified as being 'undiscovered resources' - resources that have not even been explored yet. Once uranium has been mined, it is turned into small pellets that can be used to generate electricity. Each small pellet, which is generally the size of a peanut, can generate as much power as 800kg of coal (EDF energy research). 

All the magic then happens in the nuclear reactors - the commonly used ones are called Pressurised Water Reactors (PWRs) which can be seen below:

Different components in a nuclear power reactor 

Neutrons are fired at the uranium isotope (Uranium 235) which makes it unstable. When that happens, the uranium atom splits which causes the release of more neutrons which collide with other particles to create a chain reaction. These splitting atoms, as the diagram below shows, creates a considerable amount of heat energy which is needed to create electricity down the pipeline. The process through which the uranium atom splits is known as nuclear fission, and according to a MIT study by John Deutch and Ernest Moniz in 2003, the energy released by the fission of one kilogram of uranium is typically equivalent to the energy released by around 22,000 kilograms of coal. 

How an Uranium atom splits

Once enough heat energy has been produced, water is then passed into the vessel to allow it to heat to around 300 degrees. This heated water is then passed through to the steam generator and turbines which cause this water to turn into steam so that it can turn the turbines to produce electrical energy. An electromagnetic field then turns this steam into electrical energy which is then transmitted to the transformer so that the electricity can be allocated to where it is needed e.g. houses and factories.  Phew! That was a long process.  Since the first phase of nuclear reactors in the 1940s, Stoneham (2010) explains how technological developments have made nuclear energy production more efficient over time as laboratory research has enabled scientists to make sure that heat loss is reduced in nuclear reactors. 

If you would like to see nuclear power in action, have a look at this clip from the BBC program 'Bang Goes The Theory' where the presenter explores a reactor core in Austria: