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General Advisory Committee's Majority and Minority Reports on
Building the H-Bomb
October 30, 1949
On October 29 and 30th, 1949 a panel of scientific advisors, known as the
General Advisory Committee to the Atomic Energy Commission, met to discuss how
the United States should respond to the news that the Soviet Union had an
atomic bomb. A large part of the discussion was devoted to whether or not the
United States should initiate an all-out effort to develop the hydrogen bomb.
While there was much agreement, the scientists were not unanimous on all the
issues and so they split into two groups which signed separate annexes to the
GENERAL ADVISORY COMMITTEE
to the U.S.
ATOMIC ENERGY COMMISSION
Dear Mr. Lilienthal:
At the request of the Commission, the seventeenth meeting of the General
Advisory Committee was held in Washington on October 29 and 30, 1949 to
consider some aspects of the question of whether the Commission was making all
appropriate progress in assuring the common defense and security. Dr.
Seaborg's absence in Europe prevented his attending this meeting. For purposes
of background, the Committee met with the Counsellor of the State Department,
with Dr. Henderson of AEC Intelligence, with the Chairman of the Joint Chiefs
of Staff, the Chairman of the Military Liaison Committee, the Chairman of the
Weapons Systems Evaluation Group, General Norstadt and Admiral Parsons. In
addition, as you know, we have had intimate consultations with the Commission
The report which follows falls into three parts. The first describes certain
recommendations for action by the Commission directed toward the common defense
and security. The second is an account of the nature of the super project and
of the super as a weapon, together with certain comments on which the Committee
is unanimously agreed. Attached to the report, but not a part of it, are
recommendations with regard to action on the super project which reflect the
opinions of Committee members.
The Committee plans to hold plans to hold its eighteenth meeting in the city of
Washington on December 1, 2 and 3, 1949. At that time we hope to return to
many of the questions which we could not deal with at this meeting.
J. R. Oppenheimer
THE GAC REPORT of OCTOBER 30, 1949
UNITED STATES ATOMIC ENERGY COMMISSION
WASHINGTON, DC 20545
HISTORICAL DOCUMENT NUMBER 349
David E. Lilienthal
U.S. Atomic Energy Commission
Washington 25, DC
(1) PRODUCTION. With regard to the present scale of production of fissionable
material, the General Advisory Committee has a recommendation to make the
Commission. We are not satisfied that the present scale represents either the
maximum or the optimum scale. We recognize the statutory and appropriate role
of the National Military Establishment in helping to determine that. We
believe, however, that before this issue can be settled, it will be desirable
to have from the Commission a careful analysis of what the capacities are which
are not now being employed. Thus we have in mind that an acceleration of the
program on beneficiation of low grade ores could well turn out to be possible.
We have in mind that further plants, both separation and reactor, might be
built, more rapidly to convert raw material into fissionable material. It
would seem that some notion of the costs, yields and time scales for such
undertakings would have to precede any realistic evaluation of what we should
do. We recommend that the Commission undertake such studies at high priority.
We further recommend that projects should not be dismissed because they are
expensive but that their expense be estimated.
(2) TACTICAL DELIVERY. The General Advisory Committed recommends to the
Commission an intensification of efforts to make atomic weapons available for
tactical purposes, and to give attention to the problem of integration of bomb
and carrier design in this field.
(3) NEUTRON PRODUCTION. The General Advisory Committee recommends to the
Commission the prompt initiation of a project for the production of freely
absorbable neutrons. With regard to the scale of this project the figure
per day may give a reasonable notion. Unless obstacles appear,
we suggest that the expediting of design be assigned to the Argonne National
With regard to the purposes for which these neutrons may be required, we need
to make more explicit statements. The principal purposes are the following:
(a) The production of U-233.
(b) The production of radiological warfare agents.
(c) Supplemental facilities for the test of reactor components.
(d) The conversion of U-235 to plutonium.
(e) A secondary facility for plutonium production.
(f) The production of tritium (1) for boosters, (2) for super bombs.
We view these varied objectives in a quite different light. We have a great
interest in the U-233 program, both for military and for civil purposes. We
strongly favor, subject to favorable outcome of the 1951 Eniwetok tests, the
booster program. With regard to radiological warfare, we would not wish to
alter the position previously taken by our Committee. With regard to the
conversion to plutonium, we would hardly believe that this alone could justify
the construction of these reactors, though it may be important should
unanticipated difficulties appear in the U-233 and booster programs. With
regard to the use of tritium in the super bomb, it is our unanimous hope that
this will not prove necessary. It is the opinion of the majority that the
super program itself should no be undertaken and that the Commission and its
contractors understand that construction of neutron producing reactors is not
intended as a step in the super program.
The General Advisory Committee has considered at great length the question of
whether to pursue with high priority the development of the super bomb. No
member of the Committee was willing to endorse this proposal. The reasons for
our views leading to this conclusion stem in large part from the technical
nature of the super and of the work necessary to establish it as a weapon. We
therefore here transmit an elementary account of these matters.
The basic principle of design of the super bomb is the ignition of the
thermo-nuclear DD reaction by the use of a fission bomb, and of high
temperatures, pressure, and neutron densities which accompany it. In
overwhelming probability, tritium is required as an intermediary, more easily
ignited than the deuterium itself and, in turn, capable of igniting the
deuterium. The steps which need to be taken if the super bomb is to become a
(1) The provision of tritium in amounts perhaps of several
(2) Further theoretical studies and criticisms aimed at reducing the very great
uncertainties still inherent in the behavior of this weapon under extreme
conditions of temperature, pressure and flow. (3) The engineering of designs
which may on theoretical grounds appear hopeful, particularly with regard to
the problems presented.
(4) Carefully instrumented test programs to determine whether the
deuterium-tritium mixture will be ignited by the fission
It is notable that there appears to be no experimental approach
short of actual test which will substantially add to our conviction that a
given model will or will not work, and it is also notable that because of the
unsymmetric and extremely unfamiliar conditions obtaining, some considerable
doubt will surely remain as to the soundness of theoretical anticipation. Thus
we are faced with a development which cannot be carried to the point of
conviction without the actual construction and demonstration of the essential
elements of the weapon in question. This does not mean that further
theoretical studies would be without avail. It does mean that they could not
be decisive. A final point that needs to be stressed is that many tests may be
required before a workable model has been evolved or before it has been
established beyond reasonable doubt that no such model can be evolved.
Although we are not able to give a specific probability rating for any given
model, we believe that an imaginative and concerted attack on the problem has a
better than even chance of producing the weapon within five years.
A second characteristic of the super bomb is that once the problem of
initiation has been solved, there is no limit to the explosive power of the
bomb itself except that imposed by requirements of delivery. This is because
one can continue to add deuterium-an essentially cheap material-to make larger
and larger explosions, the energy release and radioactive products of which are
both proportional to the amount of deuterium itself. Taking into account the
probable limitations of carries likely to be available for the delivery of such
a weapon, it has generally been estimated that the weapon would have an
explosive effect some hundreds of times that of present fission bombs. This
would correspond to a damage area of the order of hundreds of square miles, to
thermal radiation effects extending over a comparable area, and to very grave
contamination problems which can easily be made more acute, and may possibly be
rendered less acute, by surrounding the deuterium with uranium or other
material. It needs to be borne in mind that for delivery by ship, submarine or
other such carrier, the limitations here outlined no longer apply and that the
weapon is from a technical point of view without limitations with regard to the
damage that it can inflict.
It is clear that the use of this weapon would bring about the destruction of
innumerable human lives; it is not a weapon which can be used exclusively for
the destruction of material installations of military or semi-military
purposes. Its use therefore carries much further than the atomic bomb itself
the policy of exterminating civilian populations. It is of course true that
super bombs which are not as big as those here contemplated could be made,
provided the initiating mechanism works. In this case, however, there appears
to be no chance of their being an economical alternative to the fission weapons
themselves. It is clearly impossible with the vagueness of design and the
uncertainty as to performance as we have them at present to give anything like
a cost estimate of the super. If one uses the strict criteria of damage area
per dollar and if one accepts the limitations on air carrier capacity likely to
obtain in the years immediately ahead, it appears uncertain to us whether the
super will be cheaper or more expensive that the fission bomb.
Although the members of the Advisory Committee are not unanimous in their
proposals as to what should be done with regard to the super bomb, there are
certain elements of unanimity among us. We all hope that by one means or
another, the development of these weapons can be avoided. We are all reluctant
to see the United States take the initiative in precipitating this development.
We are all agreed that it would be wrong at the present moment to commit
ourselves to an all-out effort toward its development.
We are somewhat divided as to the nature of the commitment not to develop the
weapon. The majority feel that this should be an unqualified commitment.
Others feel that it should be made conditional on the response of the Soviet
government to a proposal to renounce such development. The Committee
recommends that enough be declassified about the super bomb so that a public
statement of policy can be made at this time. Such a statement might in our
opinion point to the use of deuterium as the principal source of energy. It
need not discuss initiating mechanisms nor the role which we believe tritium
will play. It should explain that the weapon cannon be explored without
developing it and proof-firing it. In one form or another, the statement
should express our desire not to make this development. It should explain the
scale and general nature of the destruction which its use would entail. It
should make clear that there are no known or foreseen nonmilitary applications
of this development. The separate views of the members of the Committee are
attached to this report for your use.
October 30, 1949
We have been asked by the Commission whether or not they should immediately
initiate an "all-out" effort to develop a weapon whose energy release is 100 to
1000 times greater and whose destructive power in terms of area of damage is 20
to 100 times greater than those of the present atomic bomb. We recommend
strongly against such action.
We base our recommendation on our belief that the extreme dangers to mankind
inherent in the proposal wholly outweigh any military advantage that could come
from this development. Let it be clearly realized that this is a super weapon;
it is in a totally different category from an atomic bomb. The reason for
developing such super bombs would be to have the capacity to devastate a vast
area with a single bomb. Its use would involve a decision to slaughter a vast
number of civilians. We are alarmed as to the possible global effects of the
radioactivity generated by the explosion of a few super bombs of conceivable
magnitude. If super bombs will work at all, there is no inherent limit in the
destructive power that may be attained with them. Therefore, a super bomb
might become a weapon of genocide.
The existence of such a weapon in our armory would have far-reaching effects on
world opinion; reasonable people the world over would realize that the
existence of a weapon of this type whose power of destruction is essentially
unlimited represents a threat to the future of the human race which is
intolerable. Thus we believe that the psychological effect of the weapon in
our hands would be adverse to out interest.
We believe a super bomb should never be produced. Mankind would be far better
off not to have a demonstration of the feasibility of such a weapon, until the
present climate of world opinion changes.
It is by no means certain that the weapon can be developed at all and by no
means certain that the Russians will produce one within a decade. To the
argument that the Russians may succeed in developing this weapon, we would
reply that our undertaking it will not prove a deterrent to them. Should they
use the weapon against us, reprisals by our large stock of atomic bombs would
be comparably effective to the use of a super.
In determining not to proceed to develop the super bomb, we see a unique
opportunity of providing by example some limitations on the totality of war and
thus of limiting the fear and arousing the hopes of mankind.
James B. Conant
Cyril Stanley Smith
L. A. DuBridge
Oliver E. Buckley
J. R. Oppenheimer
October 30, 1949
AN OPINION ON THE DEVELOPMENT OF THE "SUPER"
A decision on the proposal that an all-out effort be undertaken for the
development of the "Super" cannot in our opinion be separated from
consideration of broad national policy. A weapon like the "Super" is only an
advantage when its energy release is from 100-1000 times greater than that of
ordinary atomic bombs. The area of destruction therefore would run from 150 to
approximately 1000 square miles or more.
Necessarily such a weapon goes far beyond any military objective and enters the
range of very great natural catastrophes. By its very nature it cannot be
confined to a military objective but becomes a weapon which in practical effect
is almost one of genocide.
It is clear that the use of such a weapon cannot be justified on any ethical
ground which gives a human being a certain individuality and dignity even if he
happens to be a resident of an enemy country. It is evident to us that this
would be the view of peoples in other countries. Its use would put the United
States in a bad moral position relative to the peoples of the world.
Any postwar situation resulting from such a weapon would leave unresolvable
enmities for generations. A desirable peace cannot come from such an inhuman
application of force. The postwar problems would dwarf the problems which
confront us at present.
The application of this weapon with the consequent great release of
radioactivity would have results unforeseeable at present, but would certainly
render large areas unfit for habitation for long periods of time.
The fact that no limits exist to the destructiveness of this weapon makes its
very existence and the knowledge of its construction a danger to humanity as a
whole. It is necessarily an evil thing considered in any light.
For these reasons we believe it important for the President of the United
States to tell the American public, and the world, that we think it wrong on
fundamental ethical principles to initiate a program of development of such a
weapon. At the same time it would be appropriate to invite the nations of the
world to join us in a solemn pledge not to proceed in the development or
construction of weapons of this category. If such a pledge were accepted even
without control machinery, it appears highly probable that an advanced stage of
development leading to a test by another power could be detected by available
physical means. Furthermore, we have our possession, in our stockpile of
atomic bombs, the means for adequate "military" retaliation for the production
or use of a "super."
I. I. Rabi
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