sikilmahfud

Do you know human-error can cause the deaths of thousands people? Now, I’ll tell you the worst nuclear accident, Chernobyl. This accident is the explosion of nuclear reactor near Pripyat, a small city in Ukraine, in April 26, 1986. This explosion caused direct deaths for 46 workers and more than 600,000 peoples have been contaminated, and about 4000 of them died because of thyroid cancer in 1986-2004 periods.

I’ll tell you a little about how nuclear reactor works. In the core of reactor, there are radioactive materials that produce heat continuously. To keep reactor core in the safe temperature so there’s not overheated, coolant water must be flowed continuously. In reactor 4 Chernobyl (that exploding happened), there consisted of 1600 fuel channel and each of them need 28 tonnes of coolant water per hour.

That have been planned, in daytime April 25, 1986, reactor 4 will be shutted down for routine maintenance and an experiment will be held to test emergency core cooling safety during shut down process. Although reactor is in shut down condition, radioactive materials inside continue to produce heat and hence control rods must be entered here to stop it, and then removed by coolant water.

It’s the chronology about fatal human error that cause explosion of reactor 4 and blow so many radioactive materials.

Daytime, April 25, 1986
A team of engineers had arrived to test the new voltage regulating system. During shut down, the output of reactor was decreased about 50%. Unfortunately, a regional power station went offline. It can cause lack of producing electricity, hence Kiev grid controller commanded to delay the test.

April 25, 11:04 pm
This delay caused serious result. According to plan, the test should end in the daytime and in the night it just for maintenance after shut down. But because of the delay, the test was held in the night. Thus the procedure for test in the night wasn’t prepared. At that moment, there are two people who were responsible for the night shift: Alexander Akimov (the chief) and Leonid Toptunov (the reactor’s operational manager).

Because of the test, the reactor’s output was decreased, from 3200 MW to 70-100 MW.
Toptunov did a serious mistake, entered too many control rods, thus the reactor was near shut down condition (the output became 30 MW).

In that condition, the test was impossible to be held. And there was a condition that they didn’t realize: in the lower output condition like that, xenon-poisoning happened, where much of xenon-135 absorb neutrons and hence inhibit nuclear reaction.

The operators that unaware it, thought that the cause of low heat producing was too many control rods. Then they pulled out the control rods and turned off automatic control rods system, but because of xenon poisoning that inhibit nuclear reaction, the output was just 200 MW. Then the test was continued.

April 26, 1:05 am
Coolant water activated, as the routine procedure.

1:19 am
Coolant water exceeded safe limit, caused decreased heat producing and steam void. This is caused operators removed all the control rods manually.

Control rods removal caused unstable reactor condition. Steam production failure happened. In that condition, shut down should be activated but the operators disabled the shut down system.

1:23:04 am

Coolant water flow decreased and steam generators produced heat again. Unfortunately, the control rod remnants inhibited radioactive materials to reach the coolant water. Consequently, overheated happened, exceed that xenon can be absorbed. Within automatic and manual control rods disable, nothing can avoid this overheated condition.

1:23:40 am
Operators pressed AZ-5 (Rapid Emergency Defense-5) and activated SCRAM system (to shut down reactor and enter all the control rods). Unfortunately, this mechanism worked slowly, about 18-20 seconds. Ironically, the erroneous graphite tip control rods design caused control rods to remove the coolant water before nuclear reaction decreased. This condition actually increased nuclear reaction rate, therefore nuclear core overheated. Some of control rods fractured and trapped the next control rods that should be entered. In three seconds the output became 530 MW.

1:23:47 am
Seven seconds afterward, the output became 30 GW, ten times from the normal output. Consequently, it ruptured fuel channels and the pipes that was used to flow coolant water.

1:24:20 am
The first steam generators explosion happened and destroyed reactor’s roof, blew radioactive materials in the air. This explosion caused more fuel channels, control rods, and pipes destroyed.
1:24:23
Second explosion happened. More radioactive material released, and the reactor’s roof that is composed by graphite aggravated it.

All operators that work died within one week. They worked without protective suit. In short time after the accident, firefighter team arrived to extinguish this reactor. Ironically, they didn’t know if this wasn’t a regular fire. “We don’t know if it’s a nuclear reactor. No one tell us”, said Vladimir Pravik, the commander of that firefighter, that dies in May 9, 1986 because of acute radiation.

In 5 am the fire can be extinguished, but the fire inside the reactor continued until May 10, 1986. That fire was handled by many helicopters that dropped more that 5000 tonnes of sand, lead, clay, and boron, and also sprayed liquid nitrogen.

The eyewitnesses, before they died, were asked how that they felt about the radioactive contamination. They said that they tasted “metal sensation”, and they felt their face was sticked by thousands of pins and needles.

The next results, all of Pripyat residents were evacuated. Victims were inevitable. Twenty seven workers in Moldova died because of thyroid cancer in that year. Great evacuation happened in Russia, Ukraine, Belorussia, and Moldova, the areas which felt the worst effect of Chernobyl disaster. Further, radioactive materials were found in the Sweden workers’ clothes.

These are the results in human. How about the environment? Pripyat River wasn’t suitable to be consumed. Radioactive materials were accumulated in the fishes’ body. Forests that are in 4 square kilometers around Chernobyl reactors were badly damaged; the pine trees were browned and died. Some animals died, and the others stopped reproduce.

So, beware about nuclear. I think it’s better to use water or earth power plant rather than nuclear power plant. Although water power plant produce less energy than nuclear, but it’s safer.
------------------ S A V E O U R W O R L D F O R T H E B E T T E R F U T U R E-----------

Original source: wikipedia

Hi friends...
Let's join in www.freewebs.com/youthforchange
Let our ideas help our worlds for a better future....

Later, if I’ve became established in my life, I want to travelling around the world. Maybe through backpacking, real tourist, or, researching that allow me to go to overseas. Or, maybe I can join with expert photography club?

If I may choose, I’ll go to the ‘extreme’ place! What’s the meaning of ‘extreme’? I mean, I’ll go to islands that people rarely notice. Because I want to know what’s the exist things there. I think, these places are still natural and less people go to, for example, Christmas Island ( do you know this island in world map? Hehe…) , rather than Tokyo, Vancouver, or Los Angeles.

Do you know Tierra del Fuego island? I think it’s neglected area in the world map, hehe. But I want to go there! Can you imagine, an island that facing directly to Antartica! Every morning I can see and maybe, play with penguins that live there. Penguin, penguin. Funny and cute animal. If I am lucky, I can see colorful sky in the night that caused by Australis Aurora. Astonishing!

Or, I want to stay for a month in somewhere near lake in Finland. Every morning, while I wake up and stare from my window, I’ll see clear and pure water that reflecting sunlight. Behind my house, there is pine forest. I want to feel how to be a deer hunter. And in the night, I’ve already near fireplace, wearing a warm coat, and eating roasted deer that I hunted morning before, while snow falls outside. How beautiful! Peaceful! It’s difficult to be explained by word…

In addition, I like big cities like Tokyo, London, New York, and Vancouver. I want to go by Japanese fast train, Shinkansen, or having a photo about me with Liberty statue background. Faraway, faraway. Oh God, thanks for this beautiful world that You’ll show me about these beauty, scenery, and many beautiful things…..

Actually, if I notice my parents’ interests, it’s rather odd. My dad likes sport, like soccer and boxing. My mom likes politic issues. So, it’s truly my interest. Sometimes, gene’s factor doesn’t play its role, does it?

My childhood is rather odd. Sometimes I dreamed about science in my bed. For example, in a moment, I am alone in an arid and barren planet. And I saw some aliens working like coolies. In other dream, I saw a strange and very big object flying above me. Its shape likes UFO. And the pilot gave me a code through his hand. I dreamed these not only once, but sometimes! Wow, rather terrify…

Ah, forget about dreams. It just little Yose’s fantasies. Actually, in my childhood my mom often gave me science books, like stars and planets, dinosaur, some books about animals, etc. I like watch Natural Geographic too. I grate to God because in my childhood my mom didn’t give my too many comic. If not, maybe I’ll not like science like now.

When I was in elementary school, it was my fantasy time. I was often curious, when sun stops shining? Why Jupiter can’t be explorated? What is Antartica and what things are exist here?
In that time I was very socially awkward. And I was different from my friends, because not like my other friends who like comic, I like to borrow science books like how storm happen, life in North Pole, etc. Although in that time I was very socially awkward, but if I remember it, I want to back to my past!

It’s my past time. How about now? You know, my interests are become wider because of TV and video games’ effect! I like watch Matrix Revolution, Terminator, and Resident Evil. I like play science fiction games like Half-Life 2. Therefore, I began to like robot. If you came to my house, see my desktop computer! I collect many science fiction’s wallpapers and e-book.
And I hope, all of my incredible fantasies don’t stop as fantasies. I want to realize it at least one. Now, I am very desire to jump to the future!

God creatures this world variously. Nothing’s same in this world, including its fauna. Try to turn your globe! Just as you turn it for a little, it has already shown different areas and of course, different fauna for each area.

Look! For each area in this world, surely it is at least one special animal. These animals are often used as emblem for this area. Now, let’s start our journey! In this part, I’ll invite you to Asia and Australia.

1. Let’s turn your globe to east part of this world… China! And I think you’ve already known their special animal. Yeah, panda.

(this picture is taken from http://www.lesliebradshaw.com)

Panda is very funny and cute animal. Panda is a kind of bear, but it’s unique – panda eats bamboo, not meat. Panda also eats egg and insect. Their habitat is in mountains area. Panda is one of animal which is in extinction threatening. Hence it is necessary to build a panda reservation. Now, the most famous panda reservation is in Wolong, Sichuan, China.

Actually, panda is very lazy animal, especially for copulation. It is one of the factor why it’s difficult to increase their population. In addition, panda willn’t eat bamboo, if the bamboo isn’t from the nature forest!

2. Turn down your globe, and you’ll find an archipelago, Indonesia. In Indonesia, so many animals live, because there are tropical forest here. And I’ll direct your journey to Komodo Island in Nusa Tenggara, because it is one of the candidate of seven wonders of the world.

(this picture is taken from www.whozoo.com)

Komodo, a scary animal. It’s similar with a very big house lizard. I’ll tell you a story about komodo.

There was a hunter, he was chased by a komodo. In his panic, he climbed up a tree to save himself. Unfortunately, the number of komodo increased! They waited for the hunter for 2 days. What a pity.

Fortunately, in day 3, another group of hunters who coincidentially passed saved him.

In one time komodo eat, they can eat a cow which have two times of komodo’s weight. Be careful, avoid to see komodo from the near because if you are bitten, your injury will be decayed.
3. Now, direct your globe to South Asia, and look for India. You know, for centuries, the tribes in India is famous because of their strength army. This is because, not like the other armies in other areas in the world, they used elephant as their “vehicle”! So, not like horseman, their “vehicle” can help them for war, too.

(this picture is taken from http://www.time.com/)

The strength of ‘elephant-man’ of India has inspired a famous film, Lord of The Ring.

4. Turn left your globe for a little, and look for Arab peninsula, which is famous because of their desert. And guess which animal can survive well in the desert? Yes, camel. This special animal has been “exploited” for more than two centuries. Like in this picture, camel has humps as its water and grease reservation. Also, camel just excretes its urine for a very, very little. That’s why camel is number one in survival in desert.

(this picture is taken from www.starponyz.com)

5. Jump to the other continent, fasten your belt, because we’ll fly to Australia. Wow, a nice journey, isn’t it?
Australia. What animal do you think if you remember this continent? Koala, kangaroo, platypus, black swan, and more! Because people call Australia as ‘kangaroo continent’, I’ll explain about it.
Kangaroo – a famous animal because they “cradle their baby” in the pouch. Kangaroo moves with its incredible jump. An animal that I think – very agile, unique.

(this picture is taken from http://myanimal.wordpress.com)

Ironically, the kangaroo’s population in Australia is very much, even they cause damaged in the forest and agriculture environment! Fauna experts in Australia said ,“ If you want to save the environment, eat kangaroo.”

Up till now, our world is depending on natural gas and petroleum oil. Every important aspect in this world can’t be rid of these two things: transportation, cooking, even world’s politic and economy. For instance, Arab Emirates Union that’s very rich from their abundant “black gold” resources. With its abound oil sources, this country can build so many super sophisticated buildings.

However, scientists estimate, approximately in 2020’s our petroleum will be exhausted. Although many countries try to limit the use of these, it just delays for a little time. The effect will be very bad. Surely, Arab countries will be collapse, and so do countries which depend on Arab’s oil export. This is even possible that world war will be happen because so many countries struggle to get remaining oil source.

Many research are being done to solve this problem. Biofuel is the most interesting solution and it is easy to be developed. This isn’t a new thing, just not all countries apply it. Europe plan, in 2010 5.75% of their fuel for transportation are ethanol, that’s derived from wheats, beets, potatoes, or corns. And the use will be increased become 20% in 2020. The other country that use biofuel is Brazil, that is more advanced that Europe in biofuel use. A quarter of their transportation fuels in 2002 is ethanol.

From the name, biofuel means the fuel that’s derived from living creature. The common materials are the product from wet cesspool (like animal’s feces) to yield biogas, combustion of dry cesspool, or planter of the fast-growth plant like sugar cane, corn, and castor oil plant.

Certainly, not all of plant can be became biofuel ‘s material. There are two criteria. First, the plants must contain plenty of sugar, like sugar cane and beet, or contain high carbohydrate, like corn. Using yeast fermentation, sugar and carbohydrate are changed into alcohol ethyl. Second, plants that contain high vegetable oil like oil palm, castor oil plant, algae, and soybean. This vegetable oil will be heated so their viscosity will be decreased. Afterward, they will be in combustion process in diesel machine and processed chemically, and finally yield biodiesel fuel.

Biofuel that are in common developed now is still first generation (still using plant that’s consumed by human and animal). Actually, in the past our world has been used primitive biofuel, charcoal. The more modern first generation biofuel is biofuel which material is from cooking oil. There’s a peculiar machine that is used to separate cooking oil from water and other particles, so the cooking oil can be used as fuel. However, it’s annotated that it just used in limited scale because the quality of the product isn’t good enough.

The most popular first generation biofuel is biodiesel and bioalcohol. Biodiesel is common in Europe, and bioalcohol is commonly used in Brazil. Biodiesel is made from vegetable oil high-contained plant. Oil is composed with sodium hydroxide and methanol by chemical reaction and yields biodiesel (the chemical composition, methyl ethyl ether). While kinds of bioalcohol are ethanol, propanol, and butanol. Ethanol will be explained here, because it is the most common bioalcohol. Ethanol is made by sugar fermentation from wheat, beets, and the other plants that high-contained of sugar.

The main problem from biofuel is caused by the material that’s used to make biofuel. It is made by the plant which is consumed by human and animals, and it can cause severe poverty if we just rely on the mass production from the first generation biofuel. Hence, biofuel experts claim that they have been developing the second generation of biofuel, that’s not made by consumed plant, like biomass cesspool, wheat’s stem, corn’s stem, wood, and Mischantus. The expected products are biohydrogen, biomethanol, and wood diesel. Besides, scientists are doing experiment with organism that derived from DNA synthetic that can increase biofuel’s production.

The use of biofuel is very advantageous, besides it can solve the problem of oil lack, it also decrease global-warming threat, because CO2 that contained in the smoke is much greater than biofuel. Now, it’s difficult to apply biofuel massively, because there are so many poor and developed countries that relied on their agriculture production. Nevertheless, we’re much hoping that second generation biofuel success to develop, so biofuel is the most proper way to solve the world’s problem.