(d) Providing for the disposal of any existing stocks of atomic weapons and for the proper use of nuclear fuel adaptable for use in weapons.

(e) Specifying the means and methods of determining violations of its terms, setting forth such violations as shall constitute international crimes, and establishing the nature of the measures of enforcement and punishment to be imposed upon persons and upon nations guilty of violating the terms of the treaty or convention.

The judicial or other processes for determination of violations of the treaty or convention, and of punishments therefor, should be swift and certain. Serious violations of the treaty shall be reported immediately by the international control agency to the nations parties to the treaty, to the General Assembly, and to the Security Council. Once the violations constituting international crimes have been defined and the measures of enforcement and punishment therefor agreed to in the treaty or convention, there shall be no legal right, by veto or otherwise, whereby a wilful violator of the terms of the treaty or convention shall be protected from the consequences of violation of its terms.

The enforcement and punishment provisions of the treaty or convention would be ineffectual if, in any such situations, they could be rendered nugatory by the veto of a State which had voluntarily signed the treaty.

4. In consideration of the problem of violation of the terms of the treaty or convention, it should also be borne in mind that a violation might be of so grave a character as to give rise to the inherent right of self-defense recognized in article 51 of the Charter of the United Nations.

5. The treaty or convention should embrace the entire program for putting the international system of control and inspection into effect and should provide a schedule for the completion of the transitional process over a period of time, step by step, in an orderly and agreed sequence leading to the full and effective establishment of international control of atomic energy. In order that the transition may be accomplished as rapidly as possible and with safety and equity to all, this Commission should supervise the transitional process, as prescribed in the treaty or convention, and should be empowered to determine when a particular stage or stages have been completed and subsequent ones are to

commence.

Part IV: A First Report on the Scientific and Technical Aspects of the Problem of Control

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Introduction

UCLEAR PHYSICS was already a well-developed science when uranium fission was discovered in January 1939. Numerous nuclear transformations, some of them spontaneous, others induced artificially in the laboratory, were recognized as such and understood in considerable detail. It was known that nuclear energy was often set free in such transformations. Against this background, the discovery of fission was an interesting scientific event that added one more type of transformation which eventually found its natural place within the scientific picture.

But in the world of practical affairs, nuclear fission soon proved to be a discovery of the greatest consequence. Indeed, fission made possible a self-propagating release of enormous quantities of nuclear energy by means of a self-sustaining chain reaction. The first application was to mass destruction on a staggering scale. But, at the same time, the way was opened to a new era of industrial and scientific achievement.

On July 31, 1946, Committee 2 made the suggestion "that the Scientific and Technical Committee present a report on the question of whether effective control of atomic energy is possible, together with an indication of the methods by which the Scientific and Technical Committee considers that effective control can be achieved." At the beginning of our discussion, it was realized that a broad exploration of the technically possible methods of controlling atomic energy to ensure against its use as a weapon would inevitably lead us to the consideration of problems of a non-technical or political nature, which would have to be taken into account in a system of control. Since political matters are wholly within the jurisdiction of other committees of the Atomic Energy Commission, it was decided to limit ourselves strictly to the scientific and technical aspects of the question.

International negotiations may lead in the future to definite political agreements, which would determine upon a system of control. In preparing this report, we have not made any sugges tions as to the nature of such a possible future control system. The report is intended rather to draw attention to the scientific and technical facts which have to be considered in devising any system of control.

In approaching our task, we have constantly kept in mind that the problem before the United Nations Atomic Energy Commission is not solely the question of what to do about a frightful weapon, but rather the entire problem of what use shall be made of a discovery so great that its consequences will affect the future of human society.

Broadly speaking our report falls into the two following parts: First, we present the basic scientific and technical facts governing the domain of atomic energy and show that the activities leading to peaceful and destructive ends in this domain are so intimately interrelated as to be almost inseparable (Chapters 1 and 2).

Secondly, we analyze the principal activities which will be carried on in the peaceful use of atomic energy, and point out the dangers which will exist if effective safeguards are not established against the use of atomic energy for destructive ends (Chapters 3 and 4).

Our Committee has of necessity dealt with limited information. all of which is non-secret and has been previously published. Two categories of information have been available, that contained in the pre-war scientific literature and that released after the bombing of Hiroshima. Much of the information in the latter category has not been given in full nor have all the scientific statements been confirmed by full description of experimental procedures, as is usual in scientific publication. It is equally true, however, that no scientific arguments would lead one to doubt the essential accuracy

'The main body of information is contained in the well-known report by H. D. Smyth, entitled "Atomic Energy for Military Purposes," 1945. Additional information is contained in A Report on the International Control of Atomic Energy prepared for the United States Secretary of State's Committee on Atomic Energy, 1946, Lilienthal Board Report [Department of State publication 2498], and in the press release of the United States Department of State, Apr. 9, 1946. Articles and announcements have also been published in the Physical Review and in other scientific journals. Useful summaries will be found in the two volumes of "Scientific Information Transmitted to the United Nations Atomic Energy Commission by the United States Member", dated June 14, 1946 and July 10, 1946. [See Department of State publication 2661.]

of this information. It represents an orderly extension of the pre-war science of nuclear physics, and there are no apparent inconsistencies with this pre-existing body of scientific fact.

There exists a possibility that the information with which the Committee has dealt may be incomplete in another sense, namely, that major discoveries, as distinguished from technological developments, may have been made somewhere in the world but not disclosed. Such discoveries, as well as any which may be made within the next few years, might well affect some aspects of the problem of control in a significant way. Logically such a possibility cannot be excluded; on the other hand there are scientific grounds for believing that discoveries unknown to us, which might seriously invalidate our analysis of the technical aspects of control, are improbable.

However that may be, this report is based on the information available to us, and we believe that the statements contained in it are relevant and significant for the problem of control, provided no major discoveries which would fundamentally affect the field of atomic energy are made or have been made.

Chapter 5 deals with the relation of the possibility of future discoveries and inventions to the problem of control. Chapter 6 summarizes our main conclusions.

Chapter 1: The Production of Nuclear Fuels

Chain Reactions

Atomic energy in quantities useful for peace or war comes only from a nuclear chain reaction, which, like fire, is self-propagating and releases energy in proportion to the nuclear fuel consumed. Only one material found in nature in appreciable quantities has the property of "nuclear inflammability", though two other nuclear fuels can be created through the "burning" of the naturally occurring one. The nuclear fuel provided by nature is uranium-235, one of the isotopes in naturally occurring uranium, but present only in the proportion of one part in one hundred and forty. At this dilution the U-235 can be burned only under the very special circumstances achieved in a structure called a primary reactor (or

The terms "nuclear inflammability”, “burning”, and “fuel” refer to nuclear reactions which resemble ordinary combustion only in the sense that "fuel" material is used up in a self-sustaining process which releases energy. The nuclear reactions are otherwise quite unlike ordinary combustion, and do not, for example, require oxygen.

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"pile"). Otherwise, the U-235 must be partly or completely separated from the more abundant U-238. This process of isotope separation is exceedingly difficult and requires large and elaborate installations.

Two new materials (plutonium-239 or uranium-233) can be formed from U-238 or thorium in nuclear fires burning U-235. They can be isolated by chemical methods more easily than isotopes can be separated, and will serve as nuclear fuels as well as U-235.

Thus there are three materials (U-235, Pu-239, and U-233) from which nuclear energy can be obtained by a chain reaction. The reaction may be used to deliver energy at a steady rate by incorporating the fuel materials into a reactor, a lattice structure big enough to confine and utilize the neutrons which propagate the reaction from atom to atom. Controlled burning is achieved by inserting materials to absorb enough of the neutrons to prevent a run-away explosion, but not so many as to quench the reaction.

The same fuel materials may be burned explosively in an atomic bomb. Again, the amount of material must be large enough to trap and use the neutrons. The violence of the explosion depends also on the rate of burning, so materials that absorb the neutrons must be carefully excluded.

Whereas concentrated nuclear fuel is required for bombs, a less concentrated material is sufficient for peaceful applications. This has led to the suggestion that material be added which may make the fuel less suitable for bomb production, while maintaining its suitability for use in a controlled reactor. Such materials, which are called "denaturants", must be chosen so that they are extremely difficult to remove from the fuel material proper.

Raw Materials

All the manifold applications of atomic energy depend on uranium and thorium as primary raw materials. It will be useful to trace the procurement of nuclear fuels from these raw materials. The pictorial chart (Appendix 1) and the flow chart (Appendix 2) indicate the principal stages and operations in processing uranium.

The mining and extraction of uranium ore and thorium ore is essentially a conventional operation comparable in scale with other mining operations, though not as large as many.

3 A Report on the International Control of Atomic Energy by the Lilienthal Board; press release of the United States Department of State, Apr. 9, 1946; "Scientific Information Transmitted to United Nations Atomic Energy Commission by the United States Member", vol. 1, p. 18.