wolit@cbnewsm.ATT.COM (Jan Wolitzky) (06/02/89)
From: wolit@cbnewsm.ATT.COM (Jan Wolitzky)
A recent contributor asked about the mechanism for varying the
yield of nuclear weapons. Here's what the Nuclear Weapons Databook,
has to say about selectable yields (p. 31):
There is little in the open literature describing how the yields
of current nuclear weapons are varied. The actual designs
probably incorporate one (or more) of the following procedures.
In a pure fission device, the yield can be varied by varying the
timing of the initiation of the chain reaction or by interchanging
pits. In modern weapons, the chain reaction is initiated by a
neutron gun.
In a boosted fission weapon, or a thermonuclear weapon with a
boosted primary, the yield can be varied readily by carefully
selecting the amount of tritium gas bled into the fissile core
from an external reservoir.
In thermonuclear weapons with one (or more) fusion stages, the
yield is varied by tritium control or by interchanging the pits.
In addition, mechanical measures that dictate whether or not
additional fusion stages ignite could be used, although there is
no evidence in the open literature that this is done. The yield
of some older bombs in the U.S. stockpile, e.g., the B28, appears
to be varied by interchanging the pits. This procedure, which is
performed on the ground, is less flexible than selecting the yield
by tritium control, the approach used in more modern weapons.
Also (p. 38):
. . . the technology exists with most of the newest warheads to
select a variable yield by merely turning a dial.
[Reference: Thomas B. Cochran, William M. Arkin, and Milton M. Hoenig:
"Nuclear Weapons Databook, Vol. I: U.S. Nuclear Forces and
Capabilities." Cambridge, MA: Ballinger Publishing Co., 1984.]
--
Jan Wolitzky, AT&T Bell Labs, Murray Hill, NJ; 201 582-2998; mhuxd!wolit
(Affiliation given for identification purposes only)