News / Asia

IAEA: No Indication of Nuclear Reactor Meltdown in Japan

Fukushima Daiichi power plant's Unit 1 is seen in Okumamachi, Fukushima prefecture, Japan, Friday, March 11, 2011
Fukushima Daiichi power plant's Unit 1 is seen in Okumamachi, Fukushima prefecture, Japan, Friday, March 11, 2011
TEXT SIZE - +

The head of the International Atomic Energy Agency, or IAEA, said Monday in Vienna that despite problems at two nuclear power plants in Japan stemming from last week's earthquake and tsunami, there is no indication of a reactor meltdown.  But the fluid situation and fears of a possible meltdown are raising concerns.

IAEA Director General Yukiya Amano sought to calm fears about the release of radioactive gas into the air, following two explosions at the Fukushima nuclear power plant, some 200 kilometers north of Tokyo. "Despite the hydrogen explosions, reactors vessels and containment vessels stayed in tact.  As a result, the release of radioactivity was limited," he said.

Amano described the many layers of protection at the Japanese plant. "The nuclear reactors BWR [i.e., boiling water reactor] have multiple safety measures. The nuclear core is contained in reactor vessels that are made of higher [grade] steel.  Then the reactor's vessel is contained in a primary containment vessel that is made of concrete," he said.

Japan expert Daniel Aldrich of Purdue University in the U.S. state of Indiana says the situation at the stricken plant is not as serious as the 1986 nuclear power accident at Chernobyl in what is now Ukraine. "This is a smaller scale meltdown, where the fuel rods themselves have not been cooled down by water or normally by other cooling fluids.  So in this case, it means the fuel gets so hot, the rods themselves melt.  And if uncontrolled, this could build into a larger meltdown.  So right now, to our knowledge, this is only a partial meltdown," he said.

But nuclear engineer David Lochbaum with the Union of Concerned Scientists cautions that it is difficult to detect a meltdown.  "There's not an annunciator; there's not an alarm window or a computer print out that says, 'I've experienced a core meltdown.'"

A partial core meltdown occurs when nuclear fuel is not cooled for several hours and begins to melt.  A full nuclear meltdown occurs when the fuel in the core melts and falls to the bottom of the reactor's containment vessel.  If the heat ruptures the vessel, it could result a large and violent release of radiation with serious health effects.

Expert Daniel Aldrich says that so far, the release of radiation at the Fukushima plant has been similar to the 1979 accident at Three Mile Island in the United States rather than the Chernobyl disaster, the worst nuclear accident in history.

"Well we know from Chernobyl, it was a tremendously large, full meltdown, we had there in Russia.  It's possible for radioactivity to travel literally thousands of miles in the atmosphere.  From Three Mile Island though, which I think is a better to comparison to what's going on now, the maximum distance we think it traveled was just a few miles.  In fact, Three Mile Island never had provable health effects on local residents there," he said.

But physicist Edwin Lyman with the Union of Concerned Scientists says the radiation exposure levels of three U.S. helicopters crews flying far from the Fukushima plant, should be cause for concern.  "I think it's not a surprise that there would be a propagation of some fission products as far as 100 miles [from the plant], but what  is surprising is the extent of the dose rate that I heard was attributed to the airman, which seems to be a little bit higher than I would have been expected at this point," he said.

About 200,000 people have been evacuated from areas around Fukushima and other troubled nuclear power stations.  About 600 people still in homes near the Fukushima plant have been advised to remain indoors.

You May Like

Multimedia Anti-Keystone XL Protests Continue

Demonstrators are worried about pipeline's effect on climate change, their traditional way of life, health and safety More

Thailand's Political Power Struggle Continues

Court gave Prime Minister Yingluck Shinawatra until May 2 to prepare her defense over abuse of power charges but uncertainty remains over election timing More

Malaysia Plane Search Tests Limits of Ocean Mapping Technology

Expert tells VOA existing equipment’s maximum operating depth is around 6 kilometers as operation continues on ocean bed for any trace of MH370 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.
Pet Kangaroo Helps Spread Environmental Messagei
X
Penelope Poulou
April 22, 2014 5:53 PM
Children’s author Julia Heckathorn travels the world to learn about different ecosystems and endangered animals. She pours her knowledge into children’s books, hoping the next generation will right the environmental wrongs of our times. As in many children's books, the main character in Heckathorn's stories is an animal. Unlike those other characters, though, this one is real - a kangaroo, that lives in the author’s backyard. VOA’s Penelope Poulou has more.
Video

Video Pet Kangaroo Helps Spread Environmental Message

Children’s author Julia Heckathorn travels the world to learn about different ecosystems and endangered animals. She pours her knowledge into children’s books, hoping the next generation will right the environmental wrongs of our times. As in many children's books, the main character in Heckathorn's stories is an animal. Unlike those other characters, though, this one is real - a kangaroo, that lives in the author’s backyard. VOA’s Penelope Poulou has more.
Video

Video Pro-Russian Separatists Plan 'Federalization Referendum' in Eastern Ukraine

Pro-Russian separatists in eastern Ukraine say they plan to move forward next month with a referendum vote for greater autonomy, despite the Geneva agreement reached with Russia, the U.S. and Ukraine to end the political conflict. VOA's Brian Padden reports from the city of Donetsk in Eastern Ukraine.
Video

Video Pope Francis Hopes Dual Canonizations Will Reconcile Church

On April 27, two popes - John the XXIII and John Paul II - will be made saints in a ceremony at St. Peter’s Square. VOA religion correspondent Jerome Socolovsky says the dual canonization is part of the current pope’s program to reconcile liberals and conservatives in the Roman Catholic Church.
Video

Video In Capturing Nature's Majesty, Film Makes Case for Its Survival

French filmmaker Luc Jacquet won worldwide acclaim for his 2005 Academy Award-winning documentary "March of the Penguins". Now Jacquet is back with a new film that takes movie-goers deep into the heart of a tropical rainforest - not only to celebrate its grandeur, but to make the case for its survival. VOA's Rosanne Skirble reports.
Video

Video Boston Marathon Bittersweet for Many Runners

Monday's running of the Boston Marathon was bittersweet for many of the 36,000 participants as they finished the run that was interrupted by a double bombing last year. Many gathered along the route paid respect to the four people killed as a result of two bombings near the finish line. VOA's Carolyn Presutti returned to Boston this year to follow two runners, forever changed because of the crimes.
Video

Video International Students Learn Film Production in World's Movie Capital

Hollywood - which is part of Los Angeles - is the movie capital of the world, and many aspiring filmmakers go there in hopes of breaking into the movie business. Mike O'Sullivan reports that regional universities are also a magnet for students who hope to become producers or directors.
Video

Video Pacific Rim Trade Deal Proves Elusive

With the U.S.-led war in Iraq ended and American military involvement in Afghanistan winding down, President Barack Obama has sought to pivot the country's foreign policy focus towards Asia. One aspect of that pivot is the negotiation of a free-trade agreement among 12 Pacific Rim nations. But as Obama leaves this week on a trip to four Asian countries he has found it very difficult to complete the trade pact. VOA's Ken Bredemeier has more from Washington.
Video

Video Autistic Adults Face Housing, Job Challenges

Many parents of children with disabilities fear for the future of their adult child. It can be difficult to find services to help adults with disabilities - physical, mental or emotional - find work or live on their own. The mother of an autistic boy set up a foundation to advocate for the estimated 1.2 million American adults with autism, a developmental disorder that causes communication difficulties and often social difficulties. VOA's Faiza Elmasry reports.
AppleAndroid