Friday, December 8, 2017

What is Nuclear Power?

Following the disasters in Three Mile Island (1979) and Chernobyl (1986), nuclear power has been on the top of environmentalists’ villains list. Also on the list are the absence of cyclist lane, littering, and NASCAR probably. However, the same people who compiled the list in the first place are currently faced with the dilemma that nuclear can in fact be the savior to postpone an already scheduled event where everyone is invited called Destruction of Planet Earth by Greenhouse Gases; environmentalists keep on receiving emails filled with suggestions to change the name of the event, but they refuse to give respond.

Nuclear power produces zero greenhouse gas, making it an excellent pollution-free alternative to the predominant fossil fuels. Based on rough calculation, a pound of uranium – from which nuclear power is generated – can produce the same amount of energy as 1 million gallons of gasoline or 3 million pounds of coal; apparently environmentalists also understand that rough calculation is more preferable than an actual math.

The process of generating electricity always creates byproducts or at least environmental impacts. Even hydropower potentially introduces negative effects to natural habitats by altering flow of river; solar panel also produces toxic chemicals during its construction and at the end of its life. Since nuclear power plant does not create greenhouse gas as byproduct, there must be something else. Unfortunately, this something else is radioactive waste such as iridium-192, cobalt-60, cesium-137, and others things with uninteresting names. Many of them can trigger birth defects and cause cancer. There is also a chance that a person exposed to radioactive waste will transform into mutants, maybe with useless superpowers if they’re lucky enough. Nuclear power is therefore at the same time full of good promises and sinister smiles. It is basically just like Lex Luthor.

A nuclear power facility may stretch to dozens of square miles, but the witchcraft happens on subatomic levels – these are the levels where no one can see or observe without assistance from flying brooms and some pointy hats. Such facility is built for one sole purpose: generating electricity from nuclear fission – a chemical reaction where a single atom splits into two smaller nuclei.

The fuel used in nuclear power plants is enriched uranium oxide comprised of uranium-238 (96% - 97%) and uranium-235 (3% - 4%). The latter is the main fissile (capable of undergoing and sustaining nuclear fission chain reaction) isotope of uranium. Natural uranium contains much less amount U-235 so enrichment is required for more effective energy production. The enrichment process and methods will not be discussed here in details due to health and safety reasons; potential use of many advanced scientific terms can be overly abusive to the brains and may cause serious headache.

While Uranium is the heaviest natural element, it is also one of the easiest to break apart. When free neutron bumps into a U-235 atom, the neutron will get absorbed and render the entire atom unstable. At the tipping point of its unstable state, the atom splits into two smaller atoms. This fission reaction generates more free neutrons which will run into many other U-235 atoms and repeat the process to infinity. Every time an atom splits, a small portion of its original mass becomes heat or energy. Water that separates fuel tubes absorb the heat and turns into steam. Then, the steam drives a turbine which generates electricity. As a result, the self-sustaining energy creation process generates massive amount of electricity to power your light bulbs, computer, microwave, TVs, and those weird-shaped electric massagers.

What is Nuclear Power
One of the main purposes of nuclear power is to create gigantic mushroom out of smoke just few miles away from a beach

Of course a nuclear power plant houses a myriad of equipment worth millions of dollars to control the fission reaction. Simply putting uranium rods next to each other will not trigger any kind of energy-production cycle. In case you have the opportunity wander inside a nuclear facility – there is a near zero chance of it happening – you will probably bump into the nuclear reactor which contains the fuel and fission control instruments.

The fuels are comprised of around 150 (if not more) bundles of 12-foot long rods; each bundle has more than 200 individual rods made from pellets of uranium oxide. These rods are immersed in a coolant and contained inside pressure vessel. Fission reactions are controlled by the amount of neutrons used. In addition to uranium rods, a reactor also houses control rods made from neutron-absorbing element for example cadmium.

Due to the nature of the fission where there are always more neutrons than required following every atom-split occurrence - hence chain reaction - the energy-production process can go berserk. Fission also increases in speed over time and leads to uncontrolled reaction if left without some sort of interference. By inserting some control rods into the bundle, large amount of neutrons are absorbed to prevent runaway reaction. To increase the speed of fission reaction again, control rods can be partially or entirely lifted out from fuel rods.

Radioactive waste, as byproduct of nuclear fission, must be treated in the instance it is produced. This is why the reactor is housed in a concrete liner inside a pressure vessel built within a disaster-proof concrete building. Imagine a shiny steel safe where people who don’t trust the bank keep their money; because they also don’t trust the safe either, they put another safe inside it. For some reasons, these people are convinced that even two layers of security measures are not enough, so they buy a bigger safe to house the two smaller ones. Then they purchase a piece of land and build a safe house for the sole purpose of keeping money. Because it is unbelievably safe, they allow some of their richest friends to keep money for a fee. In short, they build their own bank when they don’t trust the bank.

Extra precautionary measures are critical to make sure that the nuclear fission inside the reactor is always in secure safe controlled conditions. Three Mile Island and Chernobyl disasters gave examples of what can happen if either the facility or human resource operating the facility is incapable. On the other hand, properly harnessed nuclear power accompanied by suitable radioactive waste treatment can potentially release us from the addiction to fossil fuels.