Monday, March 14, 2011

Engineering 101: A Crash Course on Nuclear Power Plant Disaster

Hello and welcome to Jacksparrow's educational 101 series program - a series dedicated to educate the non-technical people on some very technical things expressed in a very non-technical manner. This course is essential to those who want to know about technical aspects of things but do not have sufficient knowledge about them in a very short period of time. This course is elaborated in such an approach that it introduces fun and exciting way to learn things, my way.

Today we will be learning about a nuclear power plant. 

In conjunction with the issues currently going on up in the far East where the Land of the Rising Sun is located regarding a failing nuclear power plant following a tsunami attack some days back, this course is very informative to those who want to know just what the hell is going on right now. 

This course will introduce you all you need to know about a nuclear power plant, how does it commonly fail and the relation with the Fukushima Daiichi nuclear power plant that recently suffered the second explosion on its main structure.

So here goes.

* * *


Contrary to certain beliefs, a nuclear power plant is a not a powerful, mutant radioactive vegetable nor any type of mighty green plants. This statement will crush many kid's imaginative thoughts and cause them to be very angry.

A nuclear power plant is a facility where the energy from radioactive materials is harvested to produce electricity just so that the customer can enjoy electricity to light their houses, watch the TV or surfing the internet just like you are currently doing now. Before we go further, let's take a look at the image below:

Now as you can see, there are a few key components of a nuclear power plant. There are the reactor core, the steam generator, the steam turbine and the electric motor generator. We now split these four components into subchapters for better learning, to avoid confusion and to avoid sparks of rebellious movement against the academic society just because some people cannot understand certain things in life and in the same time are clouded in the fog of confusion:

1. The Reactor Core
The reactor core is where the fuel rods are housed. These fuel rods contain radioactive fuel, such as Uranium-235 and Plutonium-239 that undergoes nuclear fission when reacted. Nuclear fission produces heat. That is why a place where thermal generation takes place from chemical reactions (fission, gasification, combustion etc) is called a reactor. The key information here is: nuclear core reactor produces heat. This heat is used to heat up circulating water that goes into the reactor up to its boiling point and above, in the state of steam. If this is hard to perceive, try picture the core reactor as your common electric kettle heating coil. Both of them does the same thing - heating water up. 

2. The Steam Generator
The steam generator is essentially a tank of water with a separate pipe in its gut. This separate pipe channels the steam from the reactor core to heat up the water in the steam generator into steam, hence its name steam generator. So the point is, the steam from the reactor core is used to produce steam in the steam generator. This concept can also be seen in daily life of a university student, where sometimes one will boil water in the kettle and pour the boiling water over a can of sardine or baked beans or 'Instant Curry' wrapper in a desperate measure to have a warm dinner. Don't anyone tell me they never did this, nor ever had the idea in mind to do this.

3. The Turbine and Electric Generator
The steam from the core reactor helps produces another steam in the steam generator. Now where the hell does this steam go? In your neighbor's toilet every time he (or she, gosh I'm tired of this) flushes the toilet? Well of course not. The steam will follow a series of pipeline into a steam turbine, where the steam will move the turbine well enough to move the electric generator connected to it to produce electricity. The closes example of this electric generator motor is the dynamo set people during the old days usually attach to their bicycle wheels to generate electricity when they cycle at night, just so that they won't bump into some wild boars that are having some very hot and sexy party in the middle of the road, for unknown reasons. From hereon, the electricity is wired out to the user.

So, pretty straightforward and simple, eh? Good. As a bonus, let's take a look at the structure of a common reactor core in the image below. 

This reactor is 4-story tall and is equivalent to any building that is 4-story tall - a perfect choice for someone with suicide intention in mind. Click on the picture for larger resolution.  


Simple. Throw a curious 5-year old kid in the control room of a nuclear power plant and the reactor will melt before you are able to yell at him (or her, goddamn it this is ridiculous). 


Anyway, since most nuclear power plant operators do not let any children (and some adult too for some certain reasons) into the control system, it is safe to say that the failure of a nuclear power plant could come in two types: internal problem and external problem. 

Internal problem consists of problems created within the plant that can put the blame on the plant when it occurs. The variety includes: operators mess things up by not doing their job right, structure failure, someone forgot to close a valve while leaving another one completely open, that kind of thing. External problem includes all the external factor that can affect a nuclear power plant, most commonly in terms of a sabotage. For instance, someone, for some reason, detonates a nuclear warhead next to the power plant. But the biggest culprit of sabotage works on a nuclear power plant is also the biggest bitch that has caused many people since the dawn of men many sorts of trouble - Mother Nature. 

You don't believe me? Well who recently attacked the Fukushima Daiichi nuclear power plant? Exactly.


Everyone will experience certain uneasiness at the lower, rear part of their body.

Lets look at the reactor again as a large kettle. Suppose that the reactor core is the heating element of your average electric kettle, you have to ensure that when you boil water in it the level of water has to be above the heating element, just so that the heating element remains submerged during operation. if you keep the heating element exposed during boiling, you will cause the kettle to fail due to overheating, unless your kettle has a prevention measure that cuts out electricity should an overheating occurs. Otherwise, when you come back to the kettle after leaving it to boil water with its heating element exposed, you might find your kettle already melted. 

Melted. That's the word. 

The same goes with out large water kettle. The nuclear reactor core has within it so much energy that if not cooled will cause overheating. That is why fuel rods are supposed to be kept submerged below water level at all time during operation. This rods will continuously undergo fission that steams keep on being generated. And to shut down fuel rods operation is not as easy as turning off the power button on your small kettle. Prolonged overheating will dry out the liquid water and slowly expose the rods to air. By this time the operators will become very nervous, and the scientists who know about this will already be waiting for the next flight to places 25,000 miles away.

The overheated reactor will proceed to empty the water surrounding it and start to melt the surrounding concrete and graphite walls around them. This will result into a pond of lava. And this lava will keep on melting everything around them that until one point it is so hot that the reactor will explode. The best example of this explosion was the explosion experienced in the nuclear power plant in Chernobyl, where it sent the roof of the reactor flying 1 kilometer above its original position. 

And when that happens, it will release so much radiation that declaring a state of emergency won't help much. A perimeter hundreds of miles surrounding the plant will be affected, and many will find themselves dying in a very painful manner within hours to months from the exposures to the radiation, depending on their received radiation dosage. 


Well, first Mother Earth, over some very unfamiliar case of female angriness shook the land at 8.9 Richter scale. Everyone went upside down before it stopped. Even before these people were able to remove the stuffs that landed on their heads and trying to recover themselves after the unforeseen quake, Mother Earth sent them a huge wave from the sea, best described by these people and everyone around the world who borrowed the word as a tsunami. 

This tsunami swept and slammed on everything in its way, including the nuclear power plant. The huge amount of water caused the plant's electricity to fail. This means the pumps that pull the cooling water into the reactor stopped working. Furthermore the pipelines that channel the water were damaged, causing another trouble to resume the cooling operation. Uncooled reactors started behaving like monkeys on fire - they produced extremely huge steam from the remaining water surrounding them. The thing is, since the water pipelines were damaged, this steam did not have anywhere to go to exit the system. Since there was no way out the reactor, the steam decided to make one itself. 

When you boil water, expansion happens. This too means there is an increment in pressure. If you don't believe me, try boiling the water in your kettle with all openings closed. You will find yourself covered with boiling water and steam as the kettle explodes due to this increasing pressure that builds up during the boiling stage.

And this is what happened to the power plant. Generated steam did not have any way to go out, so they made their way out through the roof, sending roof segments flying at all directions following an explosion.  So the Japanese saw this and they decided to let seawater into the reactor to keep the reactor cool and below water level. Somewhat, another explosion as shown in the image below, took place where again it was caused by superheated vapor or steam at elevated pressures making their escape from the reactor.

Now, the reactors have to be cooled sufficiently to prevent meltdown from happening. The question whether the state of Fukushima Daiichi will face a declared state of emergency for the highest nuclear disaster alarm cannot be confidently answered. The game is to do whatever that can be done and hope for the best. 

The second explosion this morning has caused a lot of people to become very very nervous, including coming out with statements that tomorrow there will be acid rains all over Malaysia, and whoever gets exposed to it will catch cancer. 

So my question to the readers is: how does acid rain be formed here in Malaysia, when what happened has nothing to do with acidic disaster? Shouldn't we be expecting radioactive rain or something?

But don't worry. Despite the major disaster currently going on in Japan, we will hardly be affected physically except on the economic part and a few other small parts of shared benefits with Japan. If there ever is acid rain tomorrow, it will not going to be formed from the radioactive materials released in Fukushima Daiichi. Most probably it is formed from that industrial factory at the back of your house.

So stay calm, and thanks for learning with me!

Anyway.....any question? Hah.


Kairel Keflee said...

Nice info bro. Very detail.

Mohamad Nazmi Zaidi said...

Thank beb!