1.   Age is an issue now because the Energy Department is no longer turning out new warheads or new plutonium fuel to replace the existing stock.

2.   Ever since, Los Alamos and Livermore have waged a design competition to build new warheads.

3.   Even so, the Pentagon announced that it was deploying a new experimental warhead designed to penetrate deep into caves.

4.   Its plug was pulled as military strategists concluded that Moscow could overwhelm it with a rush of new warheads then being deployed.

5.   Paris insists that the main purpose of the tests is to guarantee the accuracy of its new nuclear warheads and to perfect methods for future testing by computer simulation.

6.   That would be after seven or eight underground explosions, which France says are needed to establish the reliability of a new submarine warhead.

7.   The U.S. no longer needs tests to design new warheads, assess the reliability of old warheads or rattle potential foes.

8.   Black quoted the source as saying that a permanent end to testing would make it harder to develop new warheads.

9.   But arms control advocates say Paris mostly wants to use the tests to complete the design of a new warhead.

10.   But opponents say Paris mostly wants to use the tests to complete the design of a new warhead.