BY UDUMA KALU with agency reports
THE United Nations nuclear agency, the International Atomic Energy Agency, IAEA, yesterday, said that Japan has declared a state of emergency at another earthquake-affected nuclear plant where higher-than-permitted levels of radioactivity were measured.
The IAEA said Japan informed it that the source of the radioactivity at the Onagawa power plant was being investigated. It said all three reactors at the plant are under control. Japan also said authorities at another plant have resorted to using sea water to cool a second reactor in an attempt to prevent a meltdown. Japan said earlier attempts to cool the No. 3 reactor at the Fukushima Dai-ichi plant had failed. Sea water is also being used to cool the plant’s No. 1 reactor. Sea water is corrosive and is being used as a last resort.
Chief Cabinet Secretary, Yukio Edano, also said Sunday that a hydrogen explosion could occur at Unit 3 of the Fukushima Dai-ichi nuclear complex, the latest reactor to face a possible meltdown. That follows a blast the day before in the power plant’s Unit 1, and operators attempted to prevent a meltdown there by injecting sea water into it.
Edano said: “At the risk of raising further public concern, we cannot rule out the possibility of an explosion. If there is an explosion, however, there would be no significant impact on human health.”
But Japanese authorities are operating on the presumption that possible meltdowns are under way at two nuclear reactors. A government official said, yesterday, that there have been no indications yet of hazardous emissions of radioactive material into the atmosphere.
CNN quoted Yukio Edano as saying: “We do believe that there is a possibility that meltdown has occurred. It is inside the reactor. We can’t see. However, we are assuming that a meltdown has occurred at the No. 1 reactor at the Fukushima Daiichi nuclear facility. And with reactor No. 3, we are also assuming that the possibility of a meltdown as we carry out measures.”
Tokyo Electric Power Co. said, yesterday, that another reactor of its quake-hit Fukushima nuclear power plants had lost its cooling functions, while at least 15 people at a nearby hospital were found to have been exposed to radioactivity. The utility supplier notified the government early Sunday morning that the No. 3 reactor at the No. 1 Fukushima plant had lost the ability to cool the reactor core.
The Japanese police, yesterday, said more than 10,000 people were killed in the Japan earthquake. The police spokesman, Go Sugawara, told the Associated Press, that though that was an estimate – only 400 people have been confirmed dead in Miyagi, which has a population of 2.3 million.
According to officials, more than 1,400 people were confirmed dead – including 200 people whose bodies were found Sunday along the coast – and more than 1,000 were missing in Friday’s disasters. Another 1,700 were injured.
For Japan, one of the world’s leading economies with ultramodern infrastructure, the disasters plunged ordinary life into nearly unimaginable deprivation.
Hundreds of thousands of hungry survivors huddled in darkened emergency centers that were cut off from rescuers, aid and electricity. At least 1.4 million households had gone without water since the quake struck and some 1.9 million households were without electricity.
A NUCLEAR meltdown is an informal term for a severe nuclear reactor accident that results in core damage from overheating. The term is not officially defined by the International Atomic Energy Agency or 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 unstable until it is repaired. The scrapping and disposal of the reactor core will incur substantial costs for the operator.
The fuel assemblies in a reactor core can melt if heat is not removed. A nuclear reactor does not have to remain critical for a core damage incident to occur, because decay heat continues to heat the reactor fuel assemblies after the reactor has shut down, though this heat decreases with time.