Nuclear Energy

How Do Nuclear Power Stations Work?

This is a surprisingly rarely asked question! Perhaps because “nuclear” is a word so often featured in the media, people tend to convince themselves that familiarity is equivalent to understanding.

Uranium (and sometimes Plutonium) atoms split in a process called nuclear fission. Small particles called neutrons split the molecules, releasing a vast amount of energy that can be used to boil water. The steam produced from the boiling water will spin a turbine, and the motion of this turbine is what drives electricity production. Commercial reactors contain very little fission material and plenty of control rods that can absorb excess neutrons and prevent uncontrolled reactions. [1]

How are Nuclear Power Stations Different to Nuclear Weapons?

Nuclear power plants contain approximately 4% fissile material, whereas nuclear weapons contain over 90%. Unlike power plants, where the goal is to confine and control the reaction with specialist control rods and chambers, bombs are constructed to react uncontrollably to cause as much damage as possible and accelerate the explosion. [2]

“It should be emphasised that a commercial-type power reactor simply cannot under any circumstances explode like a nuclear bomb.”

The World Nuclear Association [3]

Nuclear power plants heat our homes, power our devices and operate under strict protocols to prevent accidents. Nuclear weapons cannot compare. [2]

Are Nuclear Reactors Safe?

In 50 years of use, nuclear power generation has caused only three significant accidents; Three Mile Island, Chernobyl and Fukushima. [3] Damage to a reactor in 1979 on Three Mile Island caused no adverse health or environmental effects due to the safe containment of the radioactive material. The accident at Fukushima in 2011 was caused by a tsunami and saw no deaths or severe injury due to radioactivity. The tsunami itself, however, was destructive and killed 19,000 people.

Chernobyl was a terrible accident, caused by poorly designed Soviet reactors and poorly trained staff, which claimed 30 lives. [3]

“The operators deliberately and in violation of rules withdrew most control and safety rods from the core and switched off some important safety systems.”

A Report by the International Nuclear Safety Advisory Group [4]

These events are awful. They are shocking consequences of natural disasters, poor reactor design and human error. The safety of nuclear energy production is (quite rightfully) examined in detail.

But what about the thousands of people that die in coal mine accidents? Everybody has heard about what happened during the Chernobyl accident in Ukraine, but have you heard about the Ukrainian Donbas coal mine explosions? In 1980, 68 people died in a methane gas explosion in the coal mines in Donbas, Ukraine. In 1998, 63 people died in the same location in a similar accident. And again in 1999, killing over 50 people. And still, just a year later in 2000, killing 80 people. And again, in 2004, killing another 36 people. [5]

These accidents are senseless, repeating and largely unpreventable – yet we still rely heavily on the coal industry to provide us with energy. In contrast, nuclear power accidents are outliers and have been used to improve more recent generations of reactor design.

“The use of nuclear energy for electricity generation can be considered extremely safe.”

World Nuclear Association [3]

The accidents encountered in energy production are still negligible in comparison to the indirect deaths caused by air pollution. A study by Markandya and Wilkinson in 2007 concluded that air pollution from the burning of coal kills approximately 24.5 people for every TWh of energy produced, whereas deaths caused by air pollution from nuclear energy production are negligible. [6] The graph below summarises the findings of the paper.

[6] Number of air pollution deaths caused per TWh of electricity produced. A graphical summary of the results of Markandya and Wilkinson in 2007

How is Nuclear Waste Disposed of in the UK?

Much of the UK’s nuclear waste treatment takes place in Sellafield, where much of it is recycled, and the fissile material chemically extracted and reprocessed into mixed oxide fuel. [7] While this is a highly effective process for generating further energy from spent nuclear fuel, it is only part of the story.

The unrecyclable waste is currently stored in metal containment chambers in the Sellafield facility, but the government has plans to build a geological disposal facility underground. Geological disposal units are internationally considered the safest long-term storage solution. [8]

Nuclear waste is radioactive for a long time. Many websites estimate the time for the radioactivity to reduce to theoretically nothing. In real life, there is notable background radiation everywhere, and zero radioactivity is impossible. What we should be comparing is natural uranium ore, as this is the source material that we dig up from the ground. A more reasonable comparison reduces the time taken for radioactive decay from millions to hundreds of years. [9]

There are many developing technologies for reprocessing waste that could see that figure drop even more and even eventually eliminate the need for new nuclear material to enter the system. [9] SILEX laser separation has been described as “five times more energy-efficient” than current procedures. [10] Other upcoming recycling processes include pyroprocessing and the creation of liquid thorium fuels from nuclear reactor by-products. [9]

How Can Nuclear Power Provide a Solution to Climate Change?

Intelligent and responsible management of nuclear technologies could make a reliable backdrop to renewable energies. The main problem we face with renewables is the unreliable nature of energy production. Renewables will be making so much electricity that sometimes they may trigger a surge in the national grid, yet at other times (when the sun isn’t shining, or the wind isn’t blowing) they produce no energy at all. We don’t yet have the battery technology to store these energies, so we need a low carbon backdrop to both satisfy the demand for electricity and prevent irreversible warming to our planet. [11]

Nuclear power should not be a long-term addition to our energy supply makeup but shouldn’t be dismissed either. While other renewables such as hydropower can create the backdrop, their set up needs rigorous planning. Dams trap water behind them, flooding the area. Not only would this potentially require communities to relocate, but it may also negatively impact land use, protected species or even release carbon stores in areas surrounding the dam. [12]

[11] A Bright Future: How Some Countries Have Solved Climate Change and the Rest Can Follow by Joshua Goldstein and Staffan A. Qvist