LONDON -- An international consortium has submitted a $1.6 billion proposal to Ukraine's government to build a new "tomb" to encase the cracked structure containing the Chernobyl nuclear reactor wrecked nine years ago.


In a statement issued in London Wednesday, the Alliance consortium said it believed its plan would solve the problem of the cracking "sarcophagus" -- to be replaced as part of Ukraine's program to close down the station by the year 2000.


"Collapse of the sarcophagus would cause a new ecological disaster, and therefore taking no action cannot be considered an option," the statement said. "As it is, atmospheric and ground water pollution is already occurring."


In Kiev, the official in charge of the tomb said he was satisfied with the study 10 months after it was commissioned and financed by the European Union.


"The differences between what Western experts wanted and what we proposed have gradually narrowed. We now agree on most things, even the cost," Valentin Kupny said in an interview.


Kupny had previously admitted that the cracks in the tomb, hurriedly erected after the reactor exploded April 26, 1986, posed a potential danger and had to be replaced.


Alliance said the new structure would comprise a concrete arch with a waterproof membrane and a stainless steel lining inside.


Ukrainian officials say at least $4 billion is needed to make the station safe, but Western countries have been cautious in pledging financing.