Nuclear Fission

Controversy and demand

Nuclear fission power is a contentious topic. For thoughts on nuclear fusion which could be part of our future see that story. Globally, the risks associated are debated from the link to nuclear weapons to the treatment of radioactive waste. We’ll cover these in other stories. Usually however cost is one of the key blockers of the development of new large power stations.

Demand however is driven by four key factors:

  • Low running costs as the marginal running costs once built mean nuclear is very cheap to operate outside of the initial build and clean-up of waste at decommissioning
  • Proven dependable baseload as the technology has been proven to run dependably as a key baseload provider
  • Security of supply as the fuel is available and not tied to the same political and economic risks as fossile fuel or the link to sunny or windy weather as in the case of renewables
  • The CO2 impact if nuclear is incredibly low as there are no CO2 emissions from generation


In essence, a nuclear reactor creates heat from the fission of Uranium 235 isotope which heats the surrounding coolant. This then drives a steam turbine and generates electricity in the same way other generators do. Fission is the process whereby a heavy atom is split when it’s bombarded by a free neutron. The mass of the remaining atoms that are created is less than the original atom. This change in mass equates to the energy through the famous equation E=mc2 which makes nuclear power so much more effective than combustion.

You can read more on the technology in detail at the World Nuclear Association but there are five key types of reactor. The first two account for the majority of reactors worldwide however the UK pioneered the Magnox gas-cooled reactor.

  • Pressurised Water Reactor (PWR)
  • Boiling Water Reactor (BWR)
  • Fast Breeder Reactor (FBR)
  • High Temperature Gas Cooled Reactor (HTGR)
  • Pressurised Heavy Water Reactor (PHWR)


The first experimental electricity generated over 70 years ago on September 3rd 1948 at Oak Ridge in an X-10 graphite reactor that had been used to produce Plutonium as part of the Manhattan Project. The first large scale nuclear power plant was connected to the grid on 27th August 1956 at Calder Hall in England. Four Magnox 60 MWe generators were connected to the grid and the power plant kept generating until 2003 having run for 47 years. Note, a 5MW reactor was connected to the grid in Russia at Obninsk in 1954.

Global impact

As of September 2018 there were 454 reactors in operation in 31 countries, and a further 55 under construction. China tops the list of countries developing new nuclear power stations. The most recent was a Westinghouse Pressurised Water Reactor connected to the Chinese grid on 17th August 2018.

In 2017, over 2.5 petawatt hours of power were generated globally. This is roughly 10% of global power. The economics of nuclear power as well as associated environmental concerns around the waste mean that the future for nuclear fission is uncertain however this is a technology that is set to be with us for many decades to come.

In the UK, Hinkley Point C was given the go ahead by the UK Government in September 2016. This huge project built by EDF Energy will take many years to complete but has and will likely face further challenges.

What are your views on nuclear power and Hinckley C?

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