* Situation clearly a catastrophe -- French safety authority
* U.S. think tank says disaster may reach level seven
* Used only once before, for Chernobyl
(adds think-tank on level 7 possible)
PARIS, March 15 France's ASN nuclear safety
authority said on Tuesday the nuclear accident at Tokyo Electric
Power Co's (9501.T) Fukushima Daiichi plant could now be classed
as level six out of an international scale of one to seven.
On Monday, the ASN had rated the ongoing accident at the
plant, located 240 km (150 miles) north of Tokyo, as a five or
Level seven has been used only once, for Chernobyl in
Ukraine in 1986. The 1979 accident at the Three Mile Island
nuclear power plant in the United States was rated a level five.
"We are now in a situation that is different from
yesterday's. It is very clear that we are at a level six, which
is an intermediate level between what happened at Three Mile
Island and Chernobyl," ASN President Andre-Claude Lacoste told a
news conference in Paris on Tuesday.
"We are clearly in a catastrophe," Lacoste added, citing the
deterioration of the containment structure at Daiichi 2 as one
of the key elements supporting the ASN's more pessimistic
Two reactors exploded on Tuesday at the Fukushima Daiichi
plant after days of frantic efforts to cool them.
Japan, which rated the accident a four on Saturday, is under
global scrutiny over its handling of a nuclear crisis triggered
by a huge earthquake and tsunami that crippled three reactors
and raised fears of an uncontrolled radiation leak.
A U.S.-based think-tank said the situation had "worsened
considerably" and that it was now closer to a level 6 event,
"and it may unfortunately reach a level 7."
"A level 6 event means that consequences are broader and
countermeasures are needed to deal with the radioactive
contamination," the Institute for Science and International
Security (ISIS) said in a statement.
"A level 7 event would constitute a larger release of
radioactive material, and would require further extended
countermeasures," it said, adding the international community
should step up assistance to Japan.
(Reporting by Mathile Cru in Paris and by Sylvia Westall and
Fredrik Dahl in Vienna; writing by Marie Maitre; editing by