News / Asia

What is a Nuclear Meltdown?

Japanese officials and nuclear experts have said they cannot rule out the possibility of a nuclear meltdown at a Japanese nuclear power plant that was badly damaged by last week's earthquake and tsunami.  Here is a quick guide to the nuclear process, what can go wrong, and how to prevent catastrophe.

-- Nuclear power is produced by harnessing the heat produced by the splitting of atoms inside uranium - a process known as fission.

-- Rods packed with uranium are submerged into water, and the heat produced by the nuclear reaction creates steam, which is used to power turbines that produce electricity.

-- The nuclear reaction can be controlled utilizing rods made of neutron-absorbing material, such as boron, essentially shutting down the fission process.  But the rods still produce heat, even when control rods are in place, requiring a cooling system to maintain temperatures.

-- When the cooling system failed at Japan's Fukushima Dai-Ichi reactor Number 2, the fuel rods boiled through the available water and were for a period of hours exposed to the air.

-- If the rods get too hot, they can eventually melt, thus the term "meltdown."

-- In the event of a complete meltdown, the still-burning hot nuclear fuel could drip to the floor of the reactor.  If the containment structure around the reactor is not strong enough, the fuel potentially could be exposed to the outside environment, and can have devastating consequences for nearby communities.

-- The world's worst nuclear power disaster was in Chernobyl, Ukraine in 1986.  After an explosion at the plant, a cloud of radioactive dust spread for hundred of kilometers and was blamed for a surge of cancer deaths and birth defects. It has left some nearby towns uninhabitable to this day.

-- People also can be exposed to radiation poisoning through contaminated food and water.  A recent U.N. study estimates the Chernobyl disaster caused 6,000 cases of thyroid cancer in children, largely through contaminated milk.

-- Workers at the Fukushima plant are pumping seawater, treated with boron, to try to cool the overheating reactor cores.  This process, if successful, will completely shut down and destroy the reactor.

-- After the reactors are brought under control, nuclear technicians will either have to remove the spent fuel, or try to bury the remnants in a concrete "sarcophagus" that will prevent the excess radiation from leaking out, until they can be safely removed.

You May Like

Video Miami Cubans Divided on New US Policy

While older, more conservative Cuban Americans have promoted anti-Castro political movement for years, younger generations say economically, it is time for change More

2014 Sees Dramatic Uptick in Boko Haram Abductions

Militants suspected in latest mass kidnapping of over 100 people in Gumsuri, Nigeria on Sunday More

Video Cuba Deal Is Major Victory for Pope

Role of Francis hailed throughout US, Latin America - though some Cuban-American Catholics have mixed feelings More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Sudan School Becomes Target of Aerial Attacksi
X
December 19, 2014 12:45 AM
The school dropout rate is at an all-time high in Sudan's South Kordofan state because many schools have been destroyed during the three-year civil war between the government and SPLA-N rebel forces. Adam Bailes visited Sudan's Nuba Mountains' region and reports many children are simply too scared to go to school
Video

Video Sudan School Becomes Target of Aerial Attacks

The school dropout rate is at an all-time high in Sudan's South Kordofan state because many schools have been destroyed during the three-year civil war between the government and SPLA-N rebel forces. Adam Bailes visited Sudan's Nuba Mountains' region and reports many children are simply too scared to go to school
Video

Video VOA Reporter Tours Devastated Peshawar School

Islamist militants wearing military uniforms and strapped with explosives attacked a military run school Tuesday in the northwestern Pakistani city of Peshawar. At least 141 people were killed in the horrific attack, most of them young students. VOA reporter Ayaz Gul visited the devastated school and attended the funeral of the principal who courageously tried to save her students from the deadly attack.
Video

Video Nigerians Fleeing Boko Haram Languish in Camp Near Capital

In its five-year effort to impose Islamic law in northeastern Nigeria, the Boko Haram extremist group has killed thousands of people and forced hundreds of thousands to flee. Some of those who ran for their lives now live in squalor on the edges of the capital, Abuja. Chris Stein reports for VOA.
Video

Video Putin Says Russian Economy Will Emerge Stronger

Russian President Vladimir Putin has said his country's sinking economy will not only recover but also become stronger, despite falling oil prices and Western sanctions over Ukraine. VOA's Daniel Schearf reports.
Video

Video Detained Turkish Journalists Follow Teachings of US-Based Preacher

The Turkish government’s jailing of critical journalists has sparked international condemnation and is being seen as an effort to undermine the followers of an ailing Turkish preacher based in the United States. VOA religion reporter Jerome Socolovsky has more.
Video

Video ‘Anti-Islamization’ Marches Increase Tensions In Germany

Anti-immigrant rallies in Germany have been building in recent weeks, peaking Monday night in the city of Dresden where tens of thousands of people turned out to demonstrate against what they call the ‘Islamization’ of the West. Germany has offered asylum to more Syrian refugees than any other country, and this appears to have set off the protests. Henry Ridgwell reports from London.
Video

Video Aceh Rebuilt Decade After Tsunami, But Scars Remain

On December 26, 2004 there was an earthquake in the Indian Ocean so powerful it caused the Earth’s axis to wobble a few centimeters. Onshore on the island of Sumatra, the resulting tsunami was devastating. A decade later, VOA Correspondent Steve Herman reports from Banda Aceh, Indonesia, where although there is little remaining evidence of the physical devastation, the psychological scars among survivors remain.
Video

Video Refugees Living in Kenya Long for Peace in the Home Countries

Kenya is host to numerous refugees seeking safe haven from conflict. Immigrants from Somalia face challenges in their new lives in Kenya. Ahead of International Migrants Day (December 18) Lenny Ruvaga has more for VOA News from the Kenyan capital.

All About America

AppleAndroid