Fears of Japan nuclear meltdown rise

An explosion and feared meltdown at a Japanese nuclear plant yesterday exposed the scale of the disaster facing the country after a massive quake and tsunami left more than 1,000 dead.
Japanese Prime Minister Naoto Kan said the magnitude 8.9 quake and the terrifying tsunami that followed were an “unprecedented national disaster” and vowed to protect those living near the stricken plant.
Reactor cooling systems failed at two nuclear facilities after Friday’s record earthquake, which unleashed a terrifying 10m tsunami that tore through coastal towns and cities, destroying everything in its path.
Smoke was seen billowing from the Fukushima No. 1 atomic plant about 250km northeast of Tokyo after an explosion at the site.
Kyodo News agency said radioactive caesium had been detected near the aging facility, citing the nuclear safety agency.
However, Kan’s top spokesman, Yukio Edano, said that the Fukushima plant’s operator had reported the reactor container was not damaged and that radiation levels near it had fallen after the blast.
Kyodo and Jiji reported before the explosion that the plant “may be experiencing nuclear meltdown,” while public broadcaster NHK quoted the safety agency as saying metal tubes that contain uranium fuel may have melted.
The cooling system of the plant was damaged in the massive earthquake that struck the region 24 hours earlier, leaving authorities scrambling to fix the problem and evacuate tens of thousands of people within a 20km radius.
Thousands were evacuated near another damaged plant, Fukushima No. 2.
The atomic emergency came as the country struggled to assess the full extent of the devastation wreaked by the massive tsunami, which was unleashed by the strongest quake ever recorded in Japan.
The wall of water pulverized towns and cities along the northeastern coast. Police reportedly said 200 to 300 bodies had been found in the city of Sendai.
About 300 to 400 bodies were recovered in Rikuzentakata, a coastal town of about 23,000 people, NHK quoted the military as saying.

What Is Nuclear Meltdown?

A nuclear meltdown is an informal term for a severe nuclear reactor accident that results in core damage from overheating. The term is not recognized by the International Atomic Energy Agency nor by the U.S. Nuclear Regulatory Commission.
A meltdown occurs when a severe failure of a nuclear power plant system prevents proper cooling of the reactor core, to the extent that the nuclear fuel assemblies overheat and melt. A meltdown is considered very serious because of the potential that radioactive materials could be released into the environment. A core meltdown will also render the reactor unusable until and unless it is repaired. The scrapping and disposal of the reactor core will incur substantial costs for the operator.
Two meltdowns occurred at American civil nuclear power plants. The partial meltdown at the Fermi 1 experimental fast breeder reactor required the reactor to be repaired, though it never achieved full operation afterward. The Three Mile Island accident led to the permanent shutdown of that reactor. Both meltdowns, though dramatic incidents, did not lead to any deaths or serious injuries; no deaths or serious injuries have ever been attributed to radiation from a Western civil nuclear power plant.
Within the former Soviet Union several nuclear meltdowns of differing severity have occurred. In the most serious example, the Chernobyl disaster, design flaws and operator negligence led to a power excursion that subsequently caused a meltdown. According to a report released by the Chernobyl Forum (consisting of numerous United Nations agencies, including the International Atomic Energy Agency and the World Health Organization; the World Bank; and the Governments of Ukraine, Belarus, and Russia) the disaster killed twenty-eight persons due to acute radiation syndrome, could possibly result in up to four thousand fatal cancers at an unknown time in the future and required the permanent evacuation of an exclusion zone around the reactor. The Chernobyl plant did not have a containment building as found on Western commercial reactor designs.

Radiation level rising at Fukushima nuclear plant in quake-hit Japan

Nuclear emergency as Fukushima cooling system fails after Japan quake