In the 1960s attention was turned from using nuclear material to create atomic weapons and instead utilising its massive energy to create a domestic fuel supply. Conscious of the earth’s limited supply of organic fuels such as coal, oil and naturally occurring gas, nuclear energy was seen by many as the holy grail of safe, economically sound and sustainable energy supply.
In fact, the creation and use of industrial reactors to process radioactive elements such as uranium, thorium and plutonium to generate electricity has raised one of the most contentious and as yet unsolved problems of the last century: how do we deal with our radioactive waste?
What exactly is radioactive waste?
The University of Leeds defines radioactive waste as “the solid, liquid or gaseous waste produced by nuclear power stations, nuclear fuel production, reprocessing of spent fuel, weapons manufacture and nuclear plant decommissioning”. These types of radioactive waste, classified as ‘high level waste’ are the most harmful: without adequate protection, a human exposed to high level radioactive waste would die within seconds from acute radiation sickness. Arms production facilities and nuclear fuel processing plants aren’t the only sources of potentially harmful radioactive waste though; ‘intermediate level’ and ‘low level’ wastes are produced by hospitals, laboratories and decommissioned power plants, and all of these wastes need to be dealt with practically and safely.
Why is radioactive waste so difficult to deal with?
High level radioactive waste, such as the spent fuel rods from nuclear reactors, generates an extreme amount of heat. Normal practice is to submerge spent radioactive fuel rods in baths of boric acid, which absorbs some of the radioactivity, for a period of at least six months although in the absence of a long-term storage solution for spent fuel rods they often remain in these baths for many years. Leaving aside the immediate problem of heat generation, the fundamental aspect that makes radioactive waste so difficult to deal with is that radioactive material remains radioactive forever. However, radioactivity decreases or ‘decays’ over time. Since, as mentioned above, radioactivity doesn’t have a finite lifespan we talk about a material’s radioactive decay in terms of its ‘half-life’ – the length of time it takes for a material’s radioactivity to decrease by half.
Different variations (known as ‘isotopes’) of the same chemical element have different half-lives. A radioactive isotope of iodine (iodine-131) is routinely used in medical screening applications. It has a short half-life of just eight days, which means that it becomes harmless after a few months. By contrast, the two isotopes of uranium (uranium-238 and uranium-235) which comprise the fuel rods used in many nuclear power processing plants have half-lives of 4.47 billion years and 700 million years respectively. These uranium isotopes are comparatively harmless prior to the fission reaction which takes place to produce energy in a power plant, but produce extremely harmful radioactive by-products as a result of the process. The half-life of these now hazardous spent fuel cells – radioactive waste – is thirty years but the period of radioactive decay required to render them harmless to humans and animals is estimated to be at least 250,000 years.
So how do we deal with our radioactive waste?
Currently, the only solutions we have for dealing with hazardous radioactive waste are temporary. The least harmful, low-level radioactive waste is allowed to decay until it is no more harmful than the natural background radiation that is ever-present in the atmosphere and is then incinerated or transported to landfill sites. Intermediate and high-level radioactive waste is encased in concrete, or in Pyrex glass surrounded by a steel canister which is then buried deep beneath the ground.
So far, every long-term solution for dealing with radioactive waste has been dismissed: it cannot be launched into space until a transportation craft is produced that can be absolutely guaranteed not to break up before it leaves the earth’s atmosphere – the result of any leak of radioactive material into the atmosphere would be catastrophic for life on earth.
Radioactive waste cannot be buried beneath the Antarctic; international treaty dictates that Antarctica must remain ‘unspoilt’ by human intervention. Burial beneath the ocean floor is not an option either both for environmental reasons and for the fact that disposing any kind of waste material at sea is unilaterally banned.
As the world’s arms manufacturers and nuclear processing plants continue to produce high level radioactive waste, secure storage appears to be the only viable method of dealing with it that is currently available. But even the most secure storage facilities will require expensive periodic maintenance, and safe, isolated storage locations on an already crowded planet are inevitably finite which means that the race against time to find a conclusive method for dealing with our radioactive waste continues.
John is a guest writer from UK skip hire comparison service Skip & Bin