TOKYO - The Industrial and Nuclear Safety Oversight Japan ( NISA) Friday , March 18 , 2011 to correct the danger level of nuclear accidents from level 4 to level 5 , on a scale of 7 bedasarkan International Nuclear Events Scale (Ines ) . Immediately panic broke out after the danger level is changed. After correction this level, several newspapers reported that Japan ' s nuclear industry was in crisis with potentially dire consequences . Please note level 5 is synonymous with the level when there are accidents at Three Mile Island - 2 ( TMI - 2 ) that occurred in the United States ( U . S . ) in 1979 . Effect of TMI - 2 accident, the United States to halt all construction industry related to nuclear power plants in the country for more than 11 years. " Coverage - news like this of course only makes the layman like in Indonesia who have no clue about the nuclear power plant became very panicked at the time to read it . Making everyone understand what is happening without having to make the reader become more panic , is the current information needed to gives a clear picture of Fukushima accident today , " he was quoted as saying Indonesian Embassy in Tokyo, Japan , on Monday ( 21 / 5 / 2011 ) . Some reasons that can be used so as not to make us panic , namely : 1 . Distance Tokyo - Fukushima as far as 250 - 300 km, was established within a radius that is very safe. The radiation dose rate data in some areas north and south of Fukushima can be concluded that there is still a level that does not endanger human health . 2 . The explosion occurred at Fukushima reactor is an explosion caused by the accumulation of hydrogen gas at backers of the reactor building . The explosion was not due to nuclear fission explosion. This explosion is an explosion caused by hydrogen gas accumulates in the reactor containment building and the concrete due to the process of venting (opening pressure relieve valve , pressure regulator valve ) to decrease the pressure in reactor. Hydrogen gas generated in the reactor as a result of oxidation of the fuel cartridge made of Zircalloy . The reaction above occurs with increase in temperature of the fuel as a result of cooling system failure . The higher the fuel sheath temperature the higher the rate of reaction. The blast occurred outside the reactor , while the reactor was not damaged . Had observed an increase in radiation levels while, especially around the location of nuclear power plants. 3 . The reactor was not operating, there is no nuclear fission reactions . So the reactor accident is different from the case of Chernobyl or There Mile Island ( TMI ) , in which nuclear fission is still going on in the reactor core when the second accident occurred . Power levels of TMI - 2 reactor when the accident occurred is approximately 97 percent , and 50- 20 percent in the case of Chernobyl . Efforts are made nuclear experts in Japan today , is an effort in order to prevent the increase in the number of damaged fuel either in the spent fuel pool or in the reactor core due to residual decay heat energy results. If the fuel to melt, required a very large cost and time consuming to clean the reactors. 4 . Radioactive substances were detected at this time is a radioactive substance has a half - life is very short . In short here in the sense that a few minutes . The release of radioactive material in the form of gas that diffuses out of the reactors . Radioactive material will be immediately lost from the body by using a water rinse. Prevention is done by always using a mask and clothing that covers the entire surface of the body for people - people who work around the area of plant. For those who are outside the area 20 km around NPP Fukushima, anticipation can be done with the same anticipation to the prevention of radiation due to pollen allergy in Japan end - the end of this . For that citizens are often advised to wear masks and always rinse . 5 . Although quite old , Fukushima nuclear power plant has a high and modern security systems. The reactor was designed to follow the philosophy of Defense in Depth . Design plant is designed with a layered security to anticipate all the worst .