US redesigning its nuclear arsenal

American scientists, worried that the nation's ageing nuclear arsenal is becoming increasingly fragile, have begun designing a new generation of nuclear arms meant to be sturdier and more reliable and to have longer lives, a media report said on Monday.

The programme could help shrink the arsenal and the high cost of its maintenance, the report said quoting federal officials and private experts.

But critics were quoted as saying it could needlessly resuscitate the complex of factories and laboratories that make nuclear weapons and could possibly ignite a new arms race.

So far, The New York Times report said, the quiet effort involves only $ 9 million for warhead designers at the nation's three nuclear weapons laboratories --

Los Alamos, Livermore and Sandia.

Federal bomb experts at these heavily guarded facilities are now scrutinising secret arms data gathered over a half century for clues about how to achieve the new reliability goals.

The relatively small initial programme, involving fewer than 100 people, is expected to grow and produce finished designs in the next 5 to 10 years, culminating, if approval is sought and won, in prototype warheads, the Times said.