Nuclear power is a contentious political issue and it is something that most people hold a strong opinion on.
Some people are against nuclear power as a result of the severe consequences of nuclear power plant disasters in Chernobyl and Fukushima (when 14m waves from a tsunami led to a major incident). These incidents have greatly impacted the public’s perception of how safe nuclear power generation is and, as a direct consequence of the Fukushima disaster, Germany has pledged to close down all of its nuclear power stations by 2020.
However, you may not know that over 20% of the UK’s power is currently generated by nuclear power – enough to make ~1,400,000,000,000 cups of tea per year! The UK nuclear power industry has not had a major safety incident for over 60 years, and ensuring that power plants continue to operate safely is of paramount importance.
As some people are strongly opposed to nuclear power generation, I am always slightly apprehensive of the response that I will receive when a stranger asks me what I am researching.
One of the most interesting conversations I had was with a stranger I met on a train. After I explained that my research is focussed on improving the safety and reliability of steels used in nuclear power plants, they replied “That is all well and good, but why are we still researching nuclear power when we have all of these renewable power sources such as solar, wind, and tidal?”. Not a bad question!
However, research focussed on improving the safety of nuclear power stations is important and something that will directly impact you in a positive way. I hope that I can convince you why.
Each time you make a pot of tea you are using electricity. Electricity is indispensable to many in modern society and, with the rising popularity of the electric car, it is vital that we have a reliable electricity generation network.
Fossil fuels, such as coal, are known to contribute towards global warming and we are aiming to reduce the amount of electricity produced via these fuels. Using more renewable or nuclear power sources will help us achieve this. Renewables already account for a significant chunk of our electricity generation, but they are not 100% reliable and cannot bear the entire load alone. To keep the lights on during those cloudy days, continued operation of nuclear power plants will be critical.
My research is focused on a key component inside the nuclear power station, the reactor pressure vessel. If you imagine the nuclear reactor as a kettle, I am interested in the main outer body; the part that contains the water whilst it boils. I am sure you can envisage the problems that could be caused if this part broke whilst your kettle was bubbling away!
I am interested in ensuring that the metal we use in this part of the power plant remains strong during the many years it is in operation, as well trying to make a better steel that could, potentially, be used in future nuclear power plants. If we can create a steel that maintains its strength for longer, we will be able to safely operate nuclear power plants for extended periods of time and reduce the amount of waste we generate.
A key component of my research is the use of a specialist instrument called an atom probe. The atom probe allows me to determine the location of individual atoms within a material, as well as which element each atom is. Using this technique allows me to create a 3D model of the material that I am interested in. I am then able to “see” where each atom in the material is located.
Clusters of copper atoms as small as 15 atoms in size can greatly weaken the steels that are used in nuclear power stations. Figuring out why these clusters form in old steels is required if we want to stop them forming in the next generation of steels. Meanwhile, calculating their average size and how abundant they are is critical if we want to accurately predict how strong the steel is. The atom probe allows me to do this.
The below figure shows typical data from an atom probe experiment. The scale bar is 20nm – that is one thousand times smaller than the width of an average human hair! Each dot in the figure represents an atom from the material and each element has its own colour; iron (Fe) is pink, copper (Cu) is orange, and nickel (Ni) is green. We can see the clusters of copper that are responsible for weakening the steel.
Figure 1: Data from an atom probe experiment showing the distribution of iron (Fe), copper (Cu), and nickel (Ni) atoms in a steel used in nuclear power plants. Clusters of copper atoms can be seen.
Like the person on the train, I hope that you now have a better idea of what I do and why I do it. If you are reading this on a laptop or a tablet, I hope that you are thinking of the nuclear power plants that are safely generating the electricity you are currently using.
Figure 2: Artists impression of nuclear power plant that is to be built at Hinckley Point, Somerset. (https://www.bbc.co.uk/news/business-36897180)