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UNITED STATES
ATOMIC ENERGY COMMISSION
WASHINGTON 25, D..C..
December 17, 1953-Honorable Robert LeBaron
Chairman, Military Liaison Committee
to the Atomic Energy Commission
Dear Mr.
LeBaron:
It is clear that with the entrance of nuclear weapons into
the realm of megaton yields, new concepts of civilian defense
must be formulated which will prepare civilian defense organizations
for the destruction which would follow the detonation of such
weapons over any portion of the United States.
That this problem
was recognized both by the AEC and by the Federal Civil Defense
Administration is demonstrated in part by exchange of corresponderce
between the Federal Civil Defense Administrator and the Chairman
of the AEC (Enclosures 1 and 2)* As requested by the Civil
Defense Administrator, a "sanitized" version of the motion picture
on Operation Ivy has been prepared for showing before the group
of mayors who will be attending the Mayors' Conference sponsored
by the White House on December 14 and 15.
DOE ARCHIVES
The film, a deleted version of the film "Operation Ivy",
shows certain of the footage pertaining to the Mike Shot of
Operation Ivy.
(This film was shown to the Chief of AFSWP and
his staff on November 25, 1953.)
Ail information which would give
éeny indication as to the nature of the thermonuclear reaction,
tnecluding ic¢entity of reactants, or the manner in which the rezetion is brought about, has been deleted from the film leaving
only the clear indication that the detonation was that of a thermonuclear device.
While all specific mention of the yield of Ivy
Mike has been deleted from the film, sufficient information remains
to permit calculation of an approximate yield by a technically
qualified person. This information has been allowed to remain in
the modified version since to remove it would destroy the usefulness of the film. . The Commission has determined that declassification of the yield of the Mike device, Operation Ivy, to this
extent will not adversely affect the common defense and security.
It does not give any indication as to how such a device is designed
or built or any indication as to how it operates.
Moreover, the
yield of Mike is well within that which our foremost scientists
have often openly discussed as being possible
(e.g.
"a thousand
times more powerful than the Hiroshima bomb" -- H. A. Bethe).
In addition, the observed yield of any particular device does not
in any way imply that such a device is the most powerful or least
Secretariat Note: *Circulated as AEC 413/16 ~ vac %- Saniy Gena Se
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