Before learning about
the history of nuclear reactors, it is important to understand how nuclear
reactors work and some of the processes that take place within a reactor
complex. Many people share common misconceptions about the dangers of nuclear
reactors; understanding what exactly a reactor does will help change those
misconceptions. Throughout history, nuclear meltdowns are some of the most
prominent events involving nuclear energy, and international opinions are
changing because of some of the consequences of radioactive accidents. Understanding
what happens when meltdowns occur and the historic events that surround nuclear energy
will help the public understand how we should approach nuclear energy in the
future.
How Do Nuclear Reactors Work?
In the nuclear power industry, nuclear reactors produce energy through a process called nuclear fission. Essentially, nuclear fission is when atoms are broken down into smaller particles, releasing thermal energy. The heat given off from the splitting of the particles is used to boil water into vapor which turns hydraulic turbines to make energy. The method of energy production is simple enough, and the reaction is self-sustaining, as atoms continuously split by themselves.
What Happens When a Reactor is Turned Off?
The
reality is that at some point in the future, every nuclear power plant in the world
must eventually retire. It seems that the process would be simple – just
end the fission reaction, the water will stop boiling, and energy will cease to
be produced. The process begins with just that; workers use “control rods” made of neutron-absorbing compounds to
stabilize the uranium inside a reactor, thus ending fission by causing the
splitting of atoms to cease. But stopping the reaction is the easy part – even
after fission ends, the control rods can still retain a large amount of heat. Radioactive
waste may also arise from ending the reaction, releasing more heat. As such, control and
uranium rods are kept submerged in circulating tanks of cool water to draw
away heat. However, if the water supply runs out and cannot be refilled, the remaining
water boils off, and the hot uranium can
burn through its encasements and begin melting the reactor around it. If accidents like this occur, the
resulting meltdown could be catastrophic, but if a complete retirement process is carried out properly, no safety issues should arise.
The Process of Decommissioning a Nuclear Reactor
In order to safely
decommission a nuclear reactor, the company can choose from one of three
options: they can immediately remove and treat the remaining radioactive material, allow the material to safely decompose inside the plant until it’s at a safer
state for removal, or the company can choose to encase the material inside
cement and bury it until it decomposes entirely on its own. Whatever option a
company may choose to take, the process is still long, drawn out, extremely
expensive, and potentially hazardous.
But at some point in the future, each and every nuclear plant in the world must
one day make a choice about how best to be decommissioned. However, the
clashing opinions on nuclear power, coupled with the discrepancies between the
concern for public safety and the international need for economic and
environmental sustainability make the questions of when and how to
decommission aging nuclear plants much more difficult.
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A Brief Timeline of Nuclear Power Worldwide
Significant Nuclear Meltdowns Throughout History
Three Mile Island
Near Harrisburg, PA, in 1979, a nuclear power plant on Three Mile Island experienced a malfunction due to the failure of a water pump used to channel cooling water into a reactor. A faulty relief-valve allowed for heat to build up inside the reactor, melt part of the core, and release a small amount of radioactive waste into the surrounding atmosphere. |
Fukushima Daiichi
In 2011, after an earthquake disabled nuclear reactors at the Fukushima Daiichi Nuclear Power Station in Japan, unstable radioactive waste began to eat through its protective encasements and burned through the plant. Left with no time to properly decommission the plant, workers were reduced to pumping cold seawater into the reactor to cool the uranium rods and partially stabilize all waste before a major meltdown occurred.
In 2011, after an earthquake disabled nuclear reactors at the Fukushima Daiichi Nuclear Power Station in Japan, unstable radioactive waste began to eat through its protective encasements and burned through the plant. Left with no time to properly decommission the plant, workers were reduced to pumping cold seawater into the reactor to cool the uranium rods and partially stabilize all waste before a major meltdown occurred.
Chernobyl
Unauthorized experiments on nuclear reactors in Chernobyl, Ukraine in 1986 led to the overheating of four pressurized-water reactors. The excess heat triggered two explosions and a fire, and released large amounts of radiation into the atmosphere.
Chernobyl is by far the most disastrous nuclear accident to occur in history. The radiation released from the power plant is still the cause of countless health problems that arise in the area today. After the accident, hundreds of Ukrainian children in the surrounding area were born with birth defects and abandoned by their parents to live out their lives at various asylums and hospitals.
Unauthorized experiments on nuclear reactors in Chernobyl, Ukraine in 1986 led to the overheating of four pressurized-water reactors. The excess heat triggered two explosions and a fire, and released large amounts of radiation into the atmosphere.
Chernobyl is by far the most disastrous nuclear accident to occur in history. The radiation released from the power plant is still the cause of countless health problems that arise in the area today. After the accident, hundreds of Ukrainian children in the surrounding area were born with birth defects and abandoned by their parents to live out their lives at various asylums and hospitals.
International Nuclear and Radiological Event Scale
The International Nuclear and Radiological Event Scale (INES) is a classification system which rates nuclear accidents on a scale from zero to seven, with seven posing the most dangerous threat or hazardous effect on the outside world. On this scale, Fukushima was rated only a four out of seven, while other well-known meltdowns, Three Mile Island and Chernobyl, were rated a five out of seven and a seven out of seven on the INES, respectively.
The International Nuclear and Radiological Event Scale (INES) is a classification system which rates nuclear accidents on a scale from zero to seven, with seven posing the most dangerous threat or hazardous effect on the outside world. On this scale, Fukushima was rated only a four out of seven, while other well-known meltdowns, Three Mile Island and Chernobyl, were rated a five out of seven and a seven out of seven on the INES, respectively.
Changing Perspectives on Nuclear Reactors
Though the damage from the most recent meltdown at Fukushima paled in comparison to meltdowns like Three Mile Island or Chernobyl, the reminder of radiation danger created uneasiness on an international level, as countries have reconsidered their positions on nuclear energy.
For
countries like Germany and Switzerland, the events at Fukushima were enough to
sway the governments’ positions on nuclear power; the two countries are
currently working towards gradually phasing out of nuclear energy. Despite Fukushima’s clear example
of the dangers from nuclear power sources,
some countries such as the United
States, China, Iran, Russia, and India have supported nuclear energy even more enthusiastically.
The fear caused from the word nuclear has greatly affected the world’s future with nuclear power. The fear of what could happen in a worst-case scenario and the examples we have seen so far have pushed back every nation’s agenda in the nuclear power industry. Therefore, the key is to learn from our past to develop the future; in order to create a world in which nuclear power is a safe and profitable energy alternative, we must examine and utilize our own fear to progress towards a more positive future.
The fear caused from the word nuclear has greatly affected the world’s future with nuclear power. The fear of what could happen in a worst-case scenario and the examples we have seen so far have pushed back every nation’s agenda in the nuclear power industry. Therefore, the key is to learn from our past to develop the future; in order to create a world in which nuclear power is a safe and profitable energy alternative, we must examine and utilize our own fear to progress towards a more positive future.