It will be raised to 'Level 7' along with Fukushima Daiichi Nuclear Power Plant accident and Chernobyl nuclear plant accident

Regarding the accident at the Fukushima Daiichi Nuclear Power Station, it has been found that the government has reviewed the level of the International Nuclear Event Scale (INES) and is considering raising it to 'Level 7', which corresponds to a serious accident.

Overseas agencies had already rated the accident as equivalent to Level 6, but the Nuclear Safety and Safety Agency affirmed the accident level as 5 on 18 March . This time, there will be a two-step increase in numbers from there.

Fukushima nuclear accident, the same 'Level 7' as Chernobyl = media coverage | Reuters
http://www.reuters.com/article/topNews/idJPJAPAN-20554420110411

Fukushima Daiichi Nuclear Power Plant: Government, Level 7 Review ... Most Serious-Daily jp (Daily Newspaper)
http://mainichi.jp/select/today/news/20110412k0000m04016200c.html ( InternetArchive )

Accident evaluation To the worst level 7 NHK news
http://www3.nhk.or.jp/news/html/20110412/k10015249911.html ( InternetArchive )

Initially, NISA viewed this accident as 'no major risk to the outside of the business site' level 4 (equivalent to the Tokai Mura JCO criticality accident ), but after that, the Three Mile Island nuclear accident and I raised it to the same level 5 . Overseas, they were rated as equivalent to Level 6 by institutions such as France and the United States.

“Level 7”, which is currently under consideration, is the highest level event in the International Nuclear Event Assessment Scale, in which more than a few tens of thousands of terabeculles (131 iodine equivalent) of radioactive materials are released outside the office. The nuclear reactors and radioactive material barriers are destroyed, and it is believed that they can not be rebuilt. A comparable example is the Chernobyl nuclear power plant accident known as the worst nuclear accident ever.

The Nuclear Safety Commission estimates that up to a maximum of 10,000 tera-Becrel-scale radioactive material may have been released per hour, and it has been continuing for several hours.