• Rahul Rao

Going nuclear: nuclear for good

by Rahul Rao, Varun Rao and Yasir Aheer


Summary:

  • As with airplanes, the internet and GPS, nuclear technology first developed for the military spilt over into civilian lives and nuclear fission began to be used for energy production after World War II.

  • Nuclear fission promised clean and plentiful energy for many decades after the war.

  • Statistics bear out the safety of nuclear energy compared to traditional energy sources but high profile accidents involving nuclear energy have turned the tide of public opinion against nuclear power.


We covered the journey of nuclear fission from Ernest Rutherford’s laboratory to the Manhattan Project in a previous article. Here, we examine the use of nuclear fission for the generation of electricity in the post-war years.


Nuclear fission reactions belong to a category generally known as chain reactions. The splitting of one atom of uranium with a neutron produces three more neutrons, which, given more uranium, can split three more atoms of uranium. This chain reaction quickly runs away, leading to the fission of the entire mass of uranium in a short time and the release of a massive quantity of energy. This is clearly no good for power generation where energy needs to be released consistently, controllably and most importantly, safely.


An ingenious design uses control rods to moderate the fission reaction. These rods are made of materials that absorb neutrons and are placed between different pieces of uranium to allow an operator to remove one or more of the three neutrons from the chain reaction, thereby splitting a greater or fewer number of uranium atoms per second and regulating the rate of energy release. The concept and application of control rods is crucial to the safe use of nuclear reactors.

In the decades after World War II, the use of nuclear fission to generate energy grew quickly. From nuclear power plants in Russia and the UK, to nuclear submarines in the US, the post-war years painted nuclear power as the new, endless source of clean energy. Between 1960 and the late 1980s, global nuclear power generation grew by an incredible 300%. Even some of NASA’s spacecraft both past and present have been nuclear-powered.


Public discourse is full of polarised debate when it comes to nuclear power generation. On one hand it is hailed as a source of plentiful clean energy. On the other, concerns range from safety in case of accidents to nuclear proliferation to radioactive waste disposal. These arguments have merit.


Although somewhere near 96% of spent nuclear fuel is recycled at the site of generation, the remaining 4% still has to be disposed of safely. Equally importantly, the public has to be convinced of the safety of nuclear waste disposal for nuclear power to be broadly accepted. Although standards for disposal and storage are stringent, there have been several accidents where stored material contaminated the surrounding environment in various parts of the world [1, 2, 3] which make public trust difficult to achieve.


Of all concerns relating to nuclear power, however, the most emotionally charged is arguably the spectre of nuclear reactor accidents, given the events of Chernobyl and Fukushima Daiichi.

To be fair to nuclear energy, in both of these cases, faulty design or operational practices were identified as the cause, rather than fundamental flaws of the concept of nuclear energy. While this knowledge does nothing to alleviate the suffering of the victims, it does point to a possible future where nuclear energy is safe if best practices are followed.


The failure at Chernobyl in 1986 was traced back to a poorly designed reactor. RBMK reactors of that era, of which Chernobyl was an example, suffered from a positive value for a characteristic known as void coefficient. Positive values for the void coefficient indicate that the reactor produces more energy as cooling water boils to form steam. More energy converts even more water to steam, leading to even higher reactivity. For the more technically-minded, this is an excellent explanation of the positive void coefficient characteristic of the Chernobyl reactor that led to its doom. Modern reactors instead have negative void coefficients; they have lower reactivity as water boils to form steam.


At Fukushima Daiichi, the reactor was shutting down as planned when the earthquake hit but the diesel generators were drowned in the tsunami. These generators were required to keep circulating cooling water while the reactor was shut down. Their failure caused the water to overheat, pressure to increase and the reactor to explode. This failure could have been prevented by locating the generators higher up or by providing them an alternate air supply.


Both of these failures were followed by the strengthening of the global anti-nuclear movement. The voice of this movement has been loud enough to make some countries reconsider nuclear power. One year after Chernobyl, Italy began phasing out its nuclear reactors. In 2011 Germany shut down eight of its seventeen reactors permanently and pledged to shut the others down by 2022. In the same year, the Japanese government abandoned its pro-nuclear policy and detailed a plan to reduce its reliance on nuclear power. Over 94% of Italians polled in a referendum in 2011 voted to remain nuclear-free. In 2019, non-OECD countries led the construction of new nuclear plants, while the OECD countries seemed to be following a different trajectory. A study by the IEA suggests the production of energy via nuclear reactors in advanced economies will decline by approximately 66% between now and 2040.


What does a world without nuclear power look like? Nuclear power currently produces 10% of the global energy requirements, and 18% in OECD countries. Shutting down nuclear power entirely means this gap will have to be filled with some clean source of energy, given the current climate change crisis. Wind, hydro or solar energy production will have to grow, requiring investment and the building of infrastructure. Until these large infrastructure projects are complete, it stands to reason that some of this gap could be filled with coal, oil, or natural gas.


The argument tips in favour of nuclear power if the alternative is a traditional fossil fuel; nuclear energy’s track record when not only accidents, but also air pollution and greenhouse gas emissions are taken into account is nothing short of extraordinary when compared to gas, oil or coal. Nuclear power accounts for 0.07 deaths per terawatt-hour of energy produced, compared to 32.7 for brown coal, 24.6 for coal and 2.7 for natural gas. Renewable energy is lower still (0.02-0.04), but not by much. Filling that nuclear-sized gap will cost lives, possibly more lives than nuclear has claimed in its entire history.

From its humble beginnings in Ernest Rutherford’s laboratory, to its most terrible moments in Hiroshima and Nagasaki, the atom bomb was known to be a thing of evil. Its golden child, nuclear power, started life as a saviour before the sheen was dulled. “You either die a hero or live long enough to see yourself become the villain” mused Harvey Dent in The Dark Knight. It seems he was following in the footsteps of nuclear power.


We leave you here with the cloud of uncertainty hanging over nuclear energy. Our next article focuses on new technologies that may give nuclear energy a new lease of life and on the ultimate goal - renewable energy.


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Disclaimer: This article is based on our personal opinion and does not reflect or represent the views of any organisation that we might be associated with.