What is nuclear power? Is it safe and eco friendly? All I really know about it if from watching The Simpsons and hearing about chernobyl. But I somehow don’t think theres drums of glowing gloop laying around anywhere!
In: Technology
Nuclear power is power stations that use Nuclear Fission (or in the future Nuclear Fusion) as an energy source. Modern nuclear power plants cause controlled reactions in Fissile material like Uranium. Uranium is natural unstable and wants to break down into lighter elements, this is turn releases energy in the form of radiation and heat.
A nuclear power station encourages Fission in these materials by controlling the flow of free neutrons that shatter atoms like pool balls flying around a pool table. The resulting heat is captured using coolant, usually water, which in turn is used to turn turbines which generate electricity.
Modern Nuclear power stations are quite safe, they use different nuclear materials and techniques that make them easier and safer to operate. Environmentally speaking they are potentially better than other power stations because Nuclear power is so energy dense that you can make lots and lots of power from very little input compared the vast amount of space you need for things like Wind, Solar, and Hydro.
The big concerns with Nuclear power are safety, and Nuclear waste. The byproducts of the stations are dangerously radioactive, but we have ways of storing and disposing of this material safely. One concern is making sure such materials don’t fall into the wrong hands as the waste could be used to make dirty bombs that can irradiate an enemy (different from a nuclear bomb)
The green goop associated with nuclear power on TV doesn’t actually exist. The Uranium is metal made into rods and looks similar to steel.
Modern plants are heavily automated and have excellent safety features. An ongoing concern particularly in North America is that most of the Nuclear plants are quite old because people are generally too scared of Nuclear Power to allow newer and safer facilities to be built.
The Chernobyl disaster was the result of the Soviets cutting corners to get into the nuclear game as quickly and cheaply as possible. Such a reactor would never have been approved in the West as it was a dangerous design. Also the Soviet Government hid key details and design flaws from the very people working on the reactor to avoid embarrassing the government (and that backfired catastrophically)
3 Mile Island happened because of operator error, but the station shutdown safely despite the reactor getting damaged. The safety systems did their job.
Fukushima meanwhile was built in the early 70’s and was destroyed by an act of God Tsunami, but arguably the power station was improperly built with inadequate safeties. A similar station up the shore survived just fine because it’s designer went above and beyond on the design in terms of safety.
Therefore many of the concerns with Nuclear power is that those building the station will cut too many corners to save costs and add too much risk in the design.
Einstein’s equation, E=mc^2 , says that energy and mass are interchangeable. There’s a lot of energy stored in the binding of protons and neutrons inside of atoms. Atoms lighter than iron release energy when fused (two small atoms combining to make a larger atom), and the element you get from it is slightly lighter than the two atoms you put in. Atoms heavier than iron release energy when fissioned (split apart) and, again, the products are lighter than the fuel. That missing mass becomes energy in the form of heat and radiation.
The hard part is getting the atoms to do what you want. Fortunately, atoms much heavier than iron – like uranium – tend to be unstable and kind of already want to fission on their own. Some kinds of those atoms release a high energy neutron when they undergo fission. If that neutron hits another one of the unstable uranium atoms it will cause *that* atom to fission, too.
Nuclear power plants have fuel rods made of an unstable element like uranium that they use to control the rate of fission. They are kept in water which acts as a *mediator*. The high energy neutrons have *too much* energy and usually zip right past other atoms without interacting at all. The rods can be extended out into the water, close together. As they spontaneously undergo fission they will emit neutrons which, because of the water, have a high chance of hitting atoms in nearby fuel rods, causing atoms there to fission and release neutrons, which hit another fuel rod, and so on.
The rods can be retracted back into a safe housing that completely absorbs the neutrons so they don’t hit other fuel rods. The atoms will still spontaneously fission, but this is very slow. It won’t produce very much energy at all. To get a usable amount, you need the mediator like water. Engineers control how much energy is being generated by controlling how much of the fuel rods is extended into the water.
The energy is released as heat, which heats up the water around the fuel rods. The water is pumped through a heat exchanger to heat up another pool of water. They’re kept separate so that any contamination stays in the main pool. The other pool gets superheated and turned into steam, which expands and flows through turbines, which turn magnets, which generates electricity.
Some plants use molten salt to transfer heat for complicated technical reasons instead of water.
It’s generally very safe. A few nuclear disasters have called that safety into question, but only Chernobyl and Fukushima had much impact. Three Mile Island *almost* caused a disaster, but safety features worked properly to prevent it. Chernobyl was the result of a series of blunders that would be comedic if it hadn’t caused such a horrible disaster. Suffice it to say, a disaster of that magnitude is all but unthinkable today and not in the USSR. Fukushima was the result of one of the worst natural disasters Japan experienced in many years and, while bad, wasn’t nearly as bad as it could be.
It’s generally considered to be environmentally friendly because it creates a *ton* of power for very little waste. There are no carbon emissions, no combustion products…only some mildly radioactive products that come into contact with the nuclear core, and spent fuel rods. The problem, of course, is that those spent fuel rods are *very* dangerous and have to be carefully disposed of in specialized facilities. So the argument against them being environmentally friendly is that although they barely produce any waste that waste is very concentrated and very bad for everything. And, nuclear waste has not always been handled appropriately in the past.
In the most simple way, like I would explain to a 5 year old, nuclear energy is taking radioactive elements that are naturally very hot and using them to heat up water into steam which we use to spin a turbine that creates electricity, in the same way that a wind turbine uses the wind to spin a turbine, or a dam uses water to spin a turbine.
These radioactive elements can be dangerous if people get near them for too long, but we keep them locked up in very strong buildings. If the buildings get damaged then it can be dangerous if the elements get into the atmosphere and carried far away.
power plants work by boiling water, which creates steam, which spins a generator, that generates electricity.
the fuel source for boiling the water varies, it can be coal, it can be natural gas, or it can be nuclear power, or it can be geothermal.
some types of power plants bypass the boiling water part and just spins the turbine another way, ie hydroelectric, which uses water flow to spin the turbine, or wind power.
solar panels are slightly different which uses the photovoltaic effect to generate DC power, which is converted to AC using an inverter.
so nuclear power plants generate heat to boil water by fusion or fission, which fuses atoms or splits atoms. you have to carefully balance the rate of reaction with various factors. if you let the reaction get out of control, it’s basically the same as a nuclear bomb. so you have to very carefully and precisely control the reaction rate. if it gets too high, you might cause a reactor meltdown or in worst cases, an explosion. if it gets too low, you kill the fusion/fission process and have to restart it which takes a huge amount of initial energy.
so what happened in cherynobol was a defect in the design of the reactor which no one really understood at the time, and politics from the USSR which would rather have working reactors than not working reactors as a show of force/power, that combined with an untrained crew that didn’t understand how the reactor worked.
if you do it right, nuclear power is very safe and very efficient. the waste products can be problematic because they require very specialized disposal/storage methods.
**EDIT: Please check the REPLIES to this post instead. They’re more accurate.**
*———[Original post below]———*
*Virtually all power plants work by using heat to create steam to spin a turbine. Coal works this way, geothermal works this way, nuclear works this way… basically, uranium pellets are put into a controlled reactor, and the heat generated from that creates the steam. What makes nuclear *infinitely* more environmentally-friendly than coal is the sheer difference in the amount of heat created for the amount of fuel used, and that the waste doesn’t go into the air.*
*The glowing goop portrayed in fiction doesn’t actually exist. Uranium is just metal. After the nuclear reactions have occurred, you have *depleted uranium* — slightly less radioactive metal which is often (albeit controversially) recycled for other purposes.*
*Chernobyl was the result of exceptionally poor management, exceptionally cheap building materials, and exceptionally absent safety protocols.*
Everything around you is made up of atoms. In the late 1930s, it was discovered that some particularly large atoms can split in two (or *fission*), releasing a shockingly large amount of energy. When these atoms are arranged properly in a machine, one splitting atom can cause nearby ones to split, creating a chain reaction. Such a machine is called a *nuclear reactor*, and can convert the nuclear energy into electricity, shaft horsepower (for submarines, etc.), building heating, desalinated water, and lots of other things useful to civilization. Today, nuclear power plants worldwide produce around 400 GW of electricity, enough to power 400 million average households.
Nuclear energy is controversial due to concerns about radiation. Public support varies geographically, but nuclear is generally among the least popular forms of energy.
In short, some atoms are unstable and will break into two atoms, neutrons or protons, and release a lot of energy as heat during the process. Usually, that happens very slowly. Without outside influence, Uranium-235 (a common nuclear material) has a half-life of 703 million years, meaning in that time, half of it will degrade into smaller elements.
But, when you have a lot of it together, those stray neutrons will hit other unstable atoms and make them degrade, setting off a chain reaction, where one reaction creates one or more reactions. Nuclear power takes a bunch of unstable uranium and keeps it just barely at the point where one reaction creates another, which ends up releasing a lot of heat. That heat is sent to steam turbines to turn it into electricity.
But it has downsides; at best you’re left with nuclear waste that can’t really be used; it just needs to be stored for millions of years where it won’t kill people. At worst, if the reaction isn’t controlled, all the energy gets released at once, and the core melts down and can irradiate the area for miles around.
But on the up side, it creates a lot of power for a long time, and produces no carbon dioxide. It’s very clean if the nuclear waste is not released unintentionally
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