UP to Atomic Bomb: Decision
UP to Leo Szilard Online

I. Preamble
The only reason to treat nuclear power differently
from all the other developments in the field ofphysics is its staggering possibilities as a means ofpolitical pressure in peace and sudden destruction in
war. All present plans for the organization ofresearch, scientific and industrial development, andpublication in the field of nucleonics are conditionedby the political and military climate in which one
expects those plans to be carried out. Therefore, inmaking suggestions for the postwar organization of
nucleonics, a discussion of political problems cannot
be avoided. The scientists on this Project do notpresume to speak authoritatively on problems ofnational and international policy. However, we foundourselves, by the force of events, the last five years
in the position of a small group of citizens cognizant
of a grave danger for the safety of this country as
well as for the future of all the other nations, ofwhich the rest of mankind is unaware. We therefore
felt it our duty to urge that the political problems,arising from the mastering of atomic power, be
recognized in all their gravity, and that appropriate
steps be taken for their study and the preparation ofnecessary decisions. We hope that the creation of theCommittee by the Secretary of War to deal with all
aspects of nucleonics, indicates that these
implications have been recognized by thegovernment. We feel that our acquaintance with thescientific elements of the situation and prolonged
preoccupation with its world-wide political
implications, imposes on us the obligation to offer tothe Committee some suggestions as to the possible
solution of these grave problems.

The Franck Report, June 11, 1945--------------------------------------------------------------Report of the Committee on Political and Social
Problems
Manhattan Project "Metallurgical Laboratory"
University of Chicago, June 11, 1945
(The Franck Report)
Members of the Committee:
James Franck (Chairman)
Donald J. Hughes
J. J. Nickson
Eugene Rabinowitch
Glenn T. Seaborg
J. C. Stearns
Leo Szilard
Source: U.S. National Archives, Washington D.C.:
Record Group 77, Manhattan Engineer District
Records, Harrison-Bundy File, folder #76.
Copyright Notice: The original of this document isbelieved to be in the public domain. Its transcription
and formatting as an e-text, however, is copyright
1995-1998 by Gene Dannen (gene@dannen.com).
The URL of this page is:
http://www.dannen.com/decision/franck.html--------------------------------------------------------------SECRETThis document consists of 16 pages and 0 figures
No. 2 of 6 copies, Series A
This document contains information affecting thenational defense of the United States within themeaning of the Espionage Act, U.S.C. 50; 31 and 32.
Its transmission or the revelation of its contents inany manner to an unauthorized person is prohibitedby law.
SECRET
THIS PAGE REGRADED UNCLASSIFIED
Order Sec Army By TAG per
720564

Scientists have often before been accused ofproviding new weapons for the mutual destruction ofnations, instead of improving their well-being. It is
undoubtedly true that the discovery of flying, forexample, has so far brought much more misery thanenjoyment or profit to humanity. However, in thepast, scientists could disclaim direct responsibility
for the use to which mankind had put theirdisinterested discoveries. We cannot take the same
attitude now because the success which we haveachieved in the development of nuclear power isfraught with infinitely greater dangers than were all

Political and Social Problems
I. Preamble
II. Prospectives of Armament RaceIII. Prospectives of Agreement
IV. Methods of Control
V. Summary

1the inventions of the past. All of us, familiar with thepresent state of nucleonics, live with the vision
before our eyes of sudden destruction visited on ourown country, of Pearl Harbor disaster, repeated inthousandfold magnification, in every one of ourmajor cities.

but to the last day of the European war, we havebeen living in constant apprehension as to their
possible achievements. The knowledge that Germanscientists were working on this weapon and that theirgovernment certainly had no scruples against using it
when available, was the main motivation of theinitiative which American scientists have taken indeveloping nuclear power on such a large scale formilitary use in this country. In Russia, too, the basic
facts and implications of nuclear power were wellunderstood in 1940, and the experiences of Russianscientists in nuclear research is entirely sufficient toenable them to retrace our steps within a few years,
even if we would make all attempts to conceal them.
Furthermore, we should not expect too much successfrom attempts to keep basic information secret inpeacetime, when scientists acquainted with the workon this and associated Projects will be scattered tomany colleges and research institutions and many ofthem will continue to work on problems closely
related to those on which our developments are
based. In other words, even if we can retain ourleadership in basic knowledge of nucleonics for acertain time by maintaining the secrecy of all results
achieved on this and associated Projects, it would befoolish to hope that this can protect us for more thana few years.

In the past, science has often been able toprovide adequate protection against new weapons it
has given into the hands of an agressor, but it cannot
promise such efficient protection against thedestructive use of nuclear power. This protection can
only come from the political organization of theworld. Among all arguments calling for an efficientinternational organization for peace, the existence of
nuclear weapons is the most compelling one. In theabsence of an international authority which would
make all resort to force in international conflicts
impossible, nations could still be diverted from apath which must lead to total mutual destruction, by
a specific international agreement barring a nuclear
armaments race.
II. Prospectives of Armaments Race
It could be suggested that the danger of destruction
by nuclear weapons can be prevented - at least as far
as this country is concerned - by keeping ourdiscoveries secret for an indefinite time, or bydeveloping our nucleonic armaments at such a pacethat no other nations would think of attacking us
from fear of overwhelming retaliation.

It may be asked whether we cannot achieve amonopoly on the raw materials of nuclear power.
The answer is that even though the largest now
known deposits of uranium ores are under the control
of powers which belong to the "western" group(Canada, Belgium and British Indies); the olddeposits in Czechoslovakia are outside this sphere.
Russia is known to be mining radium on its own
territory; and even if we do not know the size of thedeposits discovered so far in the USSR, theprobability that no large reserves of uranium will befound in a country which covers 1/5 of the land areaof the earth (and whose sphere of influence takes in
additional territory), is too small to serve as a basis
for security. Thus, we cannot hope to avoid a nuclear
armament race, either by keeping secret from thecompeting nations the basic scientific facts ofnuclear power, or by cornering the raw materials
required for such a race.

The answer to the first suggestion is that
although we undoubtedly are at present ahead of therest of the world in this field, the fundamental factsof nuclear power are a subject of common
knowledge. British scientists know as much as we doabout the basic wartime progress of nucleonics - withthe exception of specific processes used in ourengineering developments - and the background of
French nuclear physicists plus their occasional
contact with our Projects, will enable them to catchup rapidly, at least as far as basic scientific facts areconcerned. German scientists, in whose discoveries
the whole development of this field has originated,apparently did not develop it during the war to thesame extent to which this has been done in America;

One could further ask whether we cannot feel2

ourselves safe in a race of nuclear armaments byvirtue of our greater industrial potential, including
greater diffusion of scientific and technicalknowledge, greater volume and efficiency of ourskilled labor corps, and greater experience of ourmanagement - all the factors whose importance has
been so strikingly demonstrated in the conversion ofthis country into an arsenal of the Allied Nations in
the present war. The answer is that all that theseadvantages can give us, is the accumulation of alarger number of bigger and better atomic bombs and this only if we produce those bombs at the
maximum of our capacity in peace time, and do not
rely on conversion of a peace time nucleonics
industry to military production after the beginning of
hostilities.

dispersal of our industry and the scattering of ourmetropolitan population will considerably decrease
the temptation of attacking us by nuclear weapons.
Ten years hence, an atomic bomb containing
perhaps 20 kg of active material, may be detonated at
6% efficiency, and thus have an effect equal to thatof 20,000 tons of TNT. One of these may be used todestroy something like 3 square miles of an urban
area. Atomic bombs containing a larger quantity ofactive material but still weighing less than one ton
may be expected to be obtainable within ten years
which could destroy over ten square miles of a city.
A nation which is able to assign 10 tons of atomic
explosives for the preparation of a sneak attack on
this country, can then hope to achieve the destructionof all industry and most of the population in an areafrom 500 square miles upwards. If no choice oftargets, in any area of five hundred square miles ofAmerican territory, will contain a large enoughfraction of the nation's industry and population to
make their destruction a crippling blow to thenation's war potential and its ability to defend itself,then the attack will not pay, and will probably not be
undertaken. At present, one could easily select in thiscountry a hundred blocks of five square miles each
whose simultaneous destruction would be a
staggering blow to the nation. (A possible total
destruction of all the nation's naval forces would be
only a small detail of such a catastrophe.) Since thearea of the United States is about six million square
miles, it should be possible to scatter its industrial
and human resources in such a way as to leave no500 square miles important enough to serve as atarget for nuclear attack.

However, such a quantitative advantage inreserves of bottled destructive power will not makeus safe from sudden attack. Just because a potential
enemy will be afraid of being "outnumbered andoutgunned," the temptation for him may beoverwhelming to attempt a sudden unprovoked blow
- particularly if he would suspect us of harboring
agressive intentions against his security or "sphere of
influence." In no other type of warfare does theadvantage lie so heavily with the agressor. He canplace his "infernal machines" in advance in all our
major cities and explode them simultaneously, thus
destroying a major part of our industry and killing alarge proportion of our population, aggregated indensely populated metropolitan districts. Ourpossibilities of retaliation - even if retaliation would
be considered compensation for the loss of tens of
millions of lives and destruction of our largest cities will be greatly handicapped because we must rely on
aerial transportation of the bombs, particularly if wewould have to deal with an enemy whose industry
and population are dispersed over a large territory.

We are fully aware of the staggering
difficulties of such a radical change in the social andeconomic structure of our nation. We felt, however,that the dilemma had to be stated, to show what kindof alternative methods of protection will have to beconsidered if no successful international agreement
is reached. It must be pointed out that in this field weare in a less favorable position than nations which
are either now more diffusely populated and whose
industries are more scattered, or whose governments
have unlimited power over the movement of
population and the location of industrial plants.

In fact, if the race of nuclear armaments isallowed to develop, the only apparent way in which
our country could be protected from the paralyzing
effects of a sudden attack is by dispersal of industries
which are essential for our war effort and dispersal of
the population of our major metropolitan cities. Aslong as nuclear bombs remain scarce (this will be thecase until uranium and thorium cease to be the only
basic materials for their fabrication) efficient

If no efficient international agreement is3

achieved, the race of nuclear armaments will be on inearnest not later than the morning after our first
demonstration of the existence of nuclear weapons.
After this, it might take other nations three or four
years to overcome our present head start, and 8 or 10
years to draw even with us if we continue to do
intensive work in this field. This might be all thetime we have to bring about the re-groupment of ourpopulation and industry. Obviously, no time should
be lost in inaugurating a study of this problem byexperts.

appropriately selected object in Japan. It is doubtful
whether the first available bombs, of comparatively
low efficiency and small size, will be sufficient tobreak the will or ability of Japan to resist, especiallygiven the fact that the major cities like Tokyo,
Nagoya, Osaka, and Kobe already will largely be
reduced to ashes by the slower process of ordinary
aerial bombing. Certain and perhaps important
tactical results undoubtedly can be achieved, but wenevertheless think that the question of the use of thevery first available atomic bombs in the Japanese
war should be weighed very carefully, not only by
military authority, but by the highest politicalleadership of this country. If we consider
international agreement on total prevention of
nuclear warfare as the paramount objective, andbelieve that it can be achieved, this kind of
introduction of atomic weapons to the world may
easily destroy all our chances of success. Russia, andeven allied countries which bear less mistrust of ourways and intentions, as well as neutral countries, will
be deeply shocked. It will be very difficult topersuade the world that a nation which was capableof secretly preparing and suddenly releasing aweapon, as indiscriminate as the rocket bomb and athousand times more destructive, is to be trusted inits proclaimed desire of having such weaponsabolished by international agreement. We have large
accumulations of poison gas, but do not use them,and recent polls have shown that public opinion inthis country would disapprove of such a use even if itwould accelerate the winning of the Far Eastern war.
It is true, that some irrational element in mass
psychology makes gas poisoning more revolting thatblasting by explosive, even though gas warfare is in
no way more "inhuman" than the war of bombs andbullets. Nevertheless, it is not at all certain that theAmerican public opinion, if it could be enlightened
as to the effect of atomic explosives, would support
the first introduction by our own country of such anindiscriminate method of wholesale destruction ofcivilian life.

III. Prospectives of Agreement
The prospect of nuclear warfare and the type ofmeasures which have to be taken to protect a country
from total destruction by nuclear bombing, must be
as abhorrent to other nations as to the United States.
England, France, and the smaller nations of theEuropean continent, with their congeries of people
and industries, are in an entirely hopeless situation in
the face of such a threat. Russia, and China are theonly great nations which could survive a nuclear
attack. However, even though these countries value
human life less than the peoples of Western Europe
and America, and even though Russia, in particular,
has an immense space over which its vital industries
could be dispersed and a government which canorder this dispersion, the day it is convinced thatsuch a measure is necessary - there is no doubt that
Russia, too, will shudder at the possibility of asudden disintegration of Moscow and Leningrad,
almost miraculously preserved in the present war,and of its new industrial sites in the Urals andSiberia. Therefore, only lack of mutual trust, and notlack of desire for agreement, can stand in the path ofan efficient agreement for the prevention of nuclear
warfare.
From this point of view, the way in which
nuclear weapons, now secretly developed in thiscountry, will first be revealed to the world appears ofgreat, perhaps fateful importance.

Thus, from the "optimistic" point of view looking forward to an international agreement on
prevention of nuclear warfare - the militaryadvantages and the saving of American lives,
achieved by the sudden use of atomic bombs against

One possible way - which may particularly
appeal to those who consider the nuclear bombs
primarily as a secret weapon developed to help win
the present war - is to use it without warning on an
4

Japan, may be outweighed by the ensuing loss ofconfidence and wave of horror and repulsion,
sweeping over the rest of the world, and perhaps
dividing even the public opinion at home.

material the comparatively abundant common
isotopes of thorium and uranium. This stage requires
no elaborate plans and can provide us in about 5 - 6years with a really substantial stockpile of atomic
bombs. Thus it is to our interest to delay the
beginning of the armaments race at least until the
successful termination of this second stage. The
benefit to the nation, and the saving of American
lives in the future, achieved by renouncing an early
demonstration of nuclear bombs and letting the othernations come into the race only reluctantly, on thebasis of guesswork and without definite knowledge
that the "thing does work," may far outweigh theadvantages to be gained by the immediate use of thefirst and comparatively inefficient bombs in the war
against Japan. At the least, pros and cons of this use
must be carefully weighed by the supreme politicaland military leadership of the country, and thedecision should not be left to considerations, merely,of military tactics.

From this point of view a demonstration of the
new weapon may best be made before the eyes ofrepresentatives of all United Nations, on the desert ora barren island. The best possible atmosphere for theachievement of an international agreement could beachieved if America would be able to say to theworld, "You see what weapon we had but did notuse. We are ready to renounce its use in the future
and to join other nations in working out adequate
supervision of the use of this nuclear weapon."This may sound fantastic, but then in nuclear
weapons we have something entirely new in theorder of magnitude of destructive power, and if wewant to capitalize fully on the advantage which its
possession gives us, we must use new andimaginative methods. After such a demonstration theweapon could be used against Japan if a sanction of
the United Nations (and of the public opinion athome) could be obtained, perhaps after a preliminary
ultimatum to Japan to surrender or at least to
evacuate a certain region as an alternative to the total
destruction of this target.

One may point out that the scientists
themselves have initiated the development of this"secret weapon" and it is therefore strange that theyshould be reluctant to try it out on the enemy as soon
as it is available. The answer to this question wasgiven above - the compelling reason for creating thisweapon with such speed was our fear that Germany
had the technical skill necessary to develop such a
weapon without any moral constraints regarding its
use.

It must be stressed that if one takes a
pessimistic point of view and discounts thepossibilities of an effective international control of
nuclear weapons, then the advisability of an early useof nuclear bombs against Japan becomes even more
doubtful - quite independently of any humanitarianconsiderations. If no international agreement isconcluded immediately after the first demonstration,
this will mean a flying start of an unlimited
armaments race. If this race is inevitable, we have allreason to delay its beginning as long as possible inorder to increase our headstart still further. It took us
three years, roughly, under forced draft of wartime
urgency, to complete the first stage of production of
nuclear explosives - that based on the separation of
the rare fissionable isotope U-235, or its utilization
for the production of an equivalent quantity of
another fissionable element. This stage requiredlarge-scale, expensive constructions and laborious
procedures. We are now on the threshold of thesecond stage - that of converting into fissionable

Another argument which could be quoted infavor of using atomic bombs as soon as they areavailable is that so much taxpayers' money has been
invested in these Projects that the Congress and theAmerican public will require a return for theirmoney. The above-mentioned attitude of theAmerican public opinion in the question of the use of
poison gas against Japan shows that one can expect it
to understand that a weapon can sometimes be madeready only for use in extreme emergency; and assoon as the potentialities of nuclear weapons will be
revealed to the American people, one can be certainthat it will support all attempts to make the use ofsuch weapons impossible.
Once this is achieved, the large installations
and the accumulation of explosive materials atpresent earmarked for potential military use, will5

become available for important peace timedevelopments, including power production, large
engineering undertakings, and mass production ofradioactive materials. In this way, the money spent
on war time development of nucleonics may becomea boon for the peace time development of national
economy.

mined. Certain difficulty with this method of control
will arise in the second stage of production, when
one pound of pure fissionable isotope will be usedagain and again to produce additional fissionable
material from thorium. These could perhaps be
overcome by extending control to the mining and useof thorium, even though the commercial use of thismetal may cause complications.

IV. Methods of International Control

If check is kept on the conversion of uranium
and thorium ore into pure fissionable materials, thequestion arises how to prevent accumulation of large
quantities of such material in the hands of one orseveral nations. Accumulations of this kind could be
rapidly converted into atomic bombs if a nation
would break away from international control. It has
been suggested that a compulsory denaturation ofpure fissionable isotopes may be agreed upon - theyshould be diluted after production by suitable
isotopes to make them useless for military purposes(except if purified by a process whose development
must take two or three years), while retaining theirusefulness for power engines.

We now consider the question of how an effective
international control of nuclear armaments can beachieved. This is a difficult problem, but we think it
to be soluble. It requires study by statesmen andinternational lawyers, and we can offer only somepreliminary suggestions for such a study.
Given mutual trust and willingness on all sides
to give up a certain part of their sovereign rights, byadmitting international control of certain phases ofnational economy, the control could be exercised(alternatively or simultaneously) on two different
levels.

One thing is clear: any international agreementon prevention of nuclear armaments must be backed
by actual and efficient controls. No paper agreement
can be sufficient since neither this or any othernation can stake its whole existence on trust into
other nations' signatures. Every attempt to impede
the international control agencies must be considered
equivalent to denunciation of the agreement.

The first and perhaps simplest way is to ration
the raw materials - primarily, the uranium ores.
Production of nuclear explosives begins withprocessing of large quantities of uranium in large
isotope separation plants or huge production piles.
The amounts of ore taken out of the ground atdifferent locations could be controlled by resident
agents of the international Control Board, and eachnation could be allotted only an amount which would
make large scale separation of fissionable isotopes
impossible.

It hardly needs stressing that we as scientists
believe that any systems of controls envisaged
should leave as much freedom for the peacedevelopment of nucleonics as is consistent with thesafety of the world.

Such a limitation would have the drawback ofmaking impossible also the development of nuclear
power production for peace time purposes. However,it does not need to prevent the production ofradioactive elements on a scale which will
revolutionize the industrial, scientific and technicaluse of these materials, and will thus not eliminate themain benefits which nucleonics promises to bring to
mankind.

Summary
The development of nuclear power not only
constitutes an important addition to the technologicaland military power of the United States, but also
creates grave political and economic problems forthe future of this country.

An agreement on a higher level, involving
more mutual trust and understanding, would be toallow unlimited production, but keep exact
bookkeeping on the fate of each pound of uranium

Nuclear bombs cannot possibly remain a"secret weapon" at the exclusive disposal of thiscountry, for more than a few years. The scientific
6facts on which their construction is based are wellknown to scientists of other countries. Unless aneffective international control of nuclear explosives
is instituted, a race of nuclear armaments is certain toensue following the first revelation of our possessionof nuclear weapons to the world. Within ten years
other countries may have nuclear bombs, each ofwhich, weighing less than a ton, could destroy anurban area of more than five square miles. In the war
to which such an armaments race is likely to lead, theUnited States, with its agglomeration of populationand industry in comparatively few metropolitan
districts, will be at a disadvantage compared to thenations whose population and industry are scatteredover large areas.

available without a demonstration, the postponementof the latter may be deemed inadvisable, because
enough information might leak out to cause othernations to start the armament race, in which we willthen be at a disadvantage. At the same time, thedistrust of other nations may be aroused by aconfirmed development under cover of secrecy,
making it more difficult eventually to reach an
agreement with them.
If the government should decide in favor of anearly demonstration of nuclear weapons it will thenhave the possibility to take into account the public
opinion of this country and of the other nations
before deciding whether these weapons should be
used in the war against Japan. In this way, othernations may assume a share of the responsibility forsuch a fateful decision.

We believe that these considerations make theuse of nuclear bombs for an early, unannounced
attack against Japan inadvisable. If the United States
would be the first to release this new means ofindiscriminate destruction upon mankind, she would
sacrifice public support throughout the world,
precipitate the race of armaments, and prejudice thepossibility of reaching an international agreement on
the future control of such weapons.

To sum up, we urge that the use of nuclear
bombs in this war be considered as a problem oflong-range national policy rather than military
expediency, and that this policy be directed primarily
to the achievement of an agreement permitting aneffective international control of the means of
nuclear warfare.

Much more favorable conditions for the
eventual achievement of such an agreement could becreated if nuclear bombs were first revealed to theworld by a demonstration in an appropriately
selected uninhabited area.

The vital importance of such a control for ourcountry is obvious from the fact that the only
effective alternative method of protecting thiscountry, of which we are aware, would be a dispersalof our major cities and essential industries.

If chances for the establishment of an effective
international control of nuclear weapons will have to
be considered slight at the present time, then not only
the use of these weapons against Japan, but even
their early demonstration may be contrary to theinterests of this country. A postponement of such ademonstration will have in this case the advantage ofdelaying the beginning of the nuclear armaments
race as long as possible. If, during the time gained,
ample support could be made available for further
development of the field in this country, thepostponement would substantially increase the leadwhich we have established during the present war,and our position in an armament race or in any later
attempt at international agreement will thus bestrengthened.

--------------------------------------------------------------UP to Atomic Bomb: Decision
UP to Leo Szilard Online
URL: http://www.dannen.com/decision/franck.html
Gene Dannen / gene@dannen.com

On the other hand, if no adequate public
support for the development of nucleonics will be7