Friday, 26 Aug 94 Washington, DC
1. HOW MUCH WEAPONS-GRADE PLUTONIUM DOES IT TAKE TO MAKE A BOMB?
With plutonium smuggled out of Russia showing up in Germany, and
with North Korea determined to make its own, maybe we ought to
know. The International Atomic Energy Agency says 8 kilograms,
but some experts think that figure was deliberately inflated to
discourage would-be proliferators. They don't seem to be all
that discouraged; one of the three plutonium seizures in Germany
amounted to 500 grams. In a report released this week by the
Natural Resources Defense Council, physicists estimate that as
little as one kilogram may be enough to make a one-kiloton bomb.
Although that may not sound like much compared to megaton bombs,
the radius of destruction would be roughly one-third that of the
Hiroshima bomb. Making bombs with less plutonium does take some-
what more sophisticated technology. In fact, Edward Teller has
been urging the development of baby bombs on the 100-ton scale to
quell small disturbances. You got a problem? Eddie's got a bomb.
2. IF YOU CAN'T GET WEAPONS-GRADE PLUTONIUM, TRY REACTOR-GRADE!
Traffic in the weapons stuff may be on the gram scale, but trade
in civilian plutonium is by the ship load
(WN 15 Jan 93). It's
awkward stuff for bombs because of a high Pu-240 content, which
builds up when Pu-239 is exposed to neutrons. In a simple design,
a high background of neutrons from spontaneous fission of Pu-240
would produce a "fizzle"--but the "fizzle yield" would still be a
few kilotons! That could be increased in a sophisticated design.
3. IF YOU'RE NOT THAT SOPHISTICATED, USE HIGHLY ENRICHED URANIUM!
The simplest design of all is the "gun type" used at Hiroshima,
but even with weapons-grade plutonium, the Pu-240 content would
be too high. That would seem to make HEU the material of choice
for unsophisticated proliferators, although it would take about
three times as much to make a bomb. To eliminate international
trade in HEU, the US has been urging our allies to stop using it
in research reactors. It seems like a reasonable request, but
for the fact that the proposed Advanced Neutron Source at Oak
Ridge calls for the use of HEU. The ANS, which has already run
into appropriations trouble
(WN 1 Jul 94), could be redesigned to
use non-weapons fuel, but at a cost in flux and operating time.
4.THE APS WASHINGTON OFFICE HAS BEEN REORGANIZED: MICHAEL LUBELL,
professor of physics at the City College of New York, is spending
his sabbatical leave in the Washington Office as Acting Director
of Public Affairs. Robert Park, who in real life is professor of
physics at the University of Maryland, continues to head the
Office and assumes the title of Director of Public Information.
5. IN THE MAIL: "ELECTRICITY BY ITS VERY NATURE IS UNPREDICTABLE"
From a flyer sent to Baltimore Gas and Electric Customers pushing
a surge protector. Michael Faraday is not available for comment.