Climate change caused by rising global CO2 is arguably the most important issue of today. A significant proportion of CO2 is emitted by the energy sector while producing electricity from fossil fuels - be they coal, gas, or oil.
In 2017, 65% of global electricity was produced from fossil fuels. And with an ever increasing world population and urbanisation, electricity demand is expected to jump accordingly in the coming decades. Even with anticipated improvements in energy efficiency, the World Energy Council estimates that global energy demand will rise by 25% in the next two decades.
So how can we reduce our dependence on fossil fuels, while meeting the increasing demand for electricity?
While low-carbon renewable electricity sources are expected to play larger roles, almost all reports on future energy supply highlight that an expanded role of nuclear power is also required to create a sustainable future energy system. Although controversial, nuclear power generation remains one of the lowest carbon emitting sources of electricity production (beating both solar and wind power but behind hydroelectric power) which is suitable for large-scale, continuous electricity demand where reliability and predictability are important.
In a nuclear reactor, the nuclear chain reaction takes place (i.e. fission), where uranium atoms split, releasing neutrons and heat. The neutrons hit other uranium atoms, causing them to split further and continue the process, generating more neutrons and more heat. This heat creates steam which turns a turbine to generate electricity.
If the world leans towards nuclear power to generate electricity capacity, this will undoubtedly impact the Zirconium and Hafnium markets, as both metals are integral to the functioning of a nuclear reactor due to their unique properties. On the one hand, Zirconium has a small thermal neutron capture cross section - this means that it acts as a neutron blocker, as it absorbs very few neutrons, and so does not interfere with the efficiency of the nuclear chain reaction. Zirconium alloys are therefore used as the cylindrical fuel rods which contain the uranium oxide granules. Conversely, Hafnium has a large thermal neutron capture cross section - this means that it absorbs many neutrons, hence is known as a neutron absorber, reducing the efficiency of the chain reaction. Thus they are used in control rods to control the fission rate and prevent the reactor from overheating. The main use for Hafnium control rods these days is in nuclear submarines.