The impact of the German V-2 and the American atomic bomb on the minds of most thinking people has been so great that the time scale and effort involved in these developments are neglected or forgotten. It would seem that the mouse labored and produced a mountain.
In some quarters this shock and confusion have produced a strange kind of algebra in which V-2 plus U-235, plus a small amount of time, equals push button war.
It is best to start the discussion by rejecting this algebra and saying that in the real time scale of the nuclear age we have seen only a few pre-dawn flashes of lightning The first question might be, why is a nuclear age possible? The answer is that for some reason not yet declassified by Nature a fairly rare isotope, actino-uranium or U-235, in an element itself as rare as silver, has the property of breaking up (fissioning) when its nucleus is struck by a slow or fast neutron. Another essential is that the fission of U-235 gives rise to from one to three neutrons to replace the one whose capture resulted in fission. This increase in the neutron population keeps the nuclear fire (chain reaction) going on in a controlled reactor or atomic pile, or in a runaway chain reaction called an atomic bomb. Two other nucleii, U-233 and plutonium-239, can be fissioned by the impact of a slow or fast neutron, but these atoms occur in Nature in such sub- microscopic quantities that for practical purposes they can be produced only by transmutation of thorium and uranium-238. This transmutation involves “burning” (fissioning) U-235 in an atomic pile or “primary reactor” to produce neutrons which may then transmute thorium-232 to uranium-233 and uranium-238 to plutonium-239.1
Thus if U-235 had been as rare as U-234 (.006% instead of its actual 0.7% in natural uranium) the nuclear age would have remained in the laboratory.
It may be useful, now that we know a few of the answers, to look backward over the long, slow time scale which preceded the discovery of nuclear fission.
Uranium oxide was discovered in 1789 by Klaproth. Either the techniques or the interest of chemists were not equal to the task of releasing its strong grip on oxygen until 1842, when this was accomplished by Peligot using potassium.
The next half century passed without radioactivity being discovered. Since physicists during these years were interested in both fluorescence and photography, certain highly fluorescent and slightly radioactive uranyl salts and photographic emulsions could have been in close proximity many times. Nature’s random signals were not heard by the right man during these years.
However, by the 1890’s so many imaginations and detecting instruments were attuned to the insistent signals from Nature that radioactivity and radium were discovered, thus bringing in the nuclear age.
The period from 1896 to 1919 was active, and ended with the discovery by Rutherford that man can change the atomic nucleus. His group had great difficulties in obtaining and observing hits on the nitrogen nucleus, using alpha particles from radium C, but their genius and techniques were equal to the task.2
From 1920 until 1932, in some respects the imaginations of physicists went ahead of their techniques. The neutron or neutral particle was recognized to be a logical necessity, and many attempts were made to detect it. In this case Nature was using a very subtle code, a particle which produced no direct electrical effect. After many attempts which were unsuccessful because the technique was not sufficiently developed, Chadwick, an associate of Rutherford, discovered the neutron in 1932.
During the next six years neutron experiments went ahead of interpretation. [Since these uncharged particles were undeflected electrically and therefore hit the nucleus with great regularity, neutrons were fired with enthusiasm against practically every known atomic nucleus. In this game the uranium nucleus was particularly interesting because scientists hoped to build so-called transuranic elements (beyond 92). We now know that Nature was sending a message “Uranium fission!” to many physicists for several years, using powerful 200 million electron volt signals that could move oscilloscopes off scale, before they and the chemists finally understood the message.
This understanding of nuclear fission came in Germany, shortly after Munich. At that time German weapons and thinking had crystallized and the initial moves in the gambit of World War II were already on the chessboard.
Nuclear fission could easily have been discovered in 1935. The full and free scientific discussion of those days might have brought home to the Nazis and the German General Staff its implications. If this had happened, World War II could have begun in the early 1940’s in a very different manner.
The German mental approach to war in the late 1930’s was brittle in that a quick victory was assumed. Perhaps for this reason no real effort was made to use the tremendous potential of German science to drive toward new developments. Perhaps also the production-minded militarists of 1938 were actually hostile to scientific assistance if it went beyond expert trouble shooting and demanded changes in design.
After Stalingrad the short-war theory had to be abandoned. Scientists were called in, but there was too little time and no organization similar to the United States Office of Scientific Research and Development to promote and coordinate the scientific effort.
Dr. S. A. Goudsmit of Northwestern University, who investigated the German atomic energy work for the United States, made the following statements in a letter to the New York Times dated February 4, 1947:
It is, of course, wise to keep the atom secrets as much as possible to ourselves to postpone an atomic war as long as we can. But don’t let this give us a false sense of security. Let us not fall into the same mistake which the Germans made. They were so convinced of their own superiority that up to the day of Hiroshima they believed themselves to be ahead of us in atomic energy research. In reality they were very far behind, and even on the wrong track.
Their fatal conceit is clearly shown in a letter to Goering, dated July, 1943, which contains the statement “ . . . considerable progress has been made in the last few months. Though our work will not lead in a short time to the construction of practical machines or explosives, it furnishes on the other hand, however, the security that the enemy powers cannot have any surprises in store for us.”
We made a safe error by overestimating the Germans. Let us avoid overestimating ourselves.
In this same July, 1943, at Los Alamos in the mountains of New Mexico we were far from overestimating our chances of success in any small number of years. We were forced to draw major deductions from experiments made with the microscopic amounts of plutonium then available.
There were many scientists in the Manhattan District who believed that the Germans were very likely to be already in the homestretch. In fact, rumors that heavy explosions had been heard in remote parts of Germany led some of these scientists to the conclusion that the Germans had already held their initial tests of atomic bombs! Since I had this opportunity to observe the reaction of many American and British scientists under the stress of all-out pre- atomic war, and with the added realization that the Germans might soon strike with atomic bombs, I am not easily convinced by statements that human nerves will fail under similar conditions.
The facts that nuclear fission was discovered in 1939 and that in less than three years of all-out scientific and industrial effort beginning in 1942 the atomic bomb was produced as a combat weapon, should not be taken as the basis for prediction of other tremendous nuclear developments in a short time. Technical and political progress at this pre-dawn stage in the atomic time scale depend on the solution of several major long- haul problems.
The first is a teaching problem at the level of graduate students. In order to make real progress in nuclear development we must transmit the basic knowledge of this new field from the present handful of physicists to a larger and younger group of potential scientists and development engineers. This process is going on now. Dividends can be expected in about five years.
The second long-haul technical problem has to do with availability of uranium and thorium. As mentioned earlier, uranium is estimated to be about as abundant as silver, taken as an average, in the earth’s outer crust. Thorium is slightly more abundant. Fortunately for the atomic bomb development of 1942-45 there had been for two generations a fairly thorough search of many countries for pitchblende ore which contains both uranium and radium. However, before any widespread industrial use of nuclear energy is made there must be a search for additional sources of high grade ore. This must be paralleled by development of methods of processing low grade ore.
Progress toward international control of atomic energy began with the Truman, Attlee, King declaration in Washington on November 15, 1945. Essentially the same proposals were formulated at the Moscow Conference of Foreign Ministers of Russia, the United Kingdom, and the United States in December, 1945. These basic proposals, on January 24, 1946, became the terms of reference of the United Nations Atomic Energy Commission, saying:
In particular, the commission shall make specific proposals:
(a) for extending between all nations the exchange of basic scientific information for peaceful ends;
(b) for control of atomic energy to the extent necessary to ensure its use only for peaceful purposes;
(c) for the elimination from national armaments of atomic weapons and of all other major weapons adaptable to mass destruction;
(d) for effective safeguards by way of inspection and other means to protect complying States against the hazards of violations and evasions.
The first meeting of the United Nations Atomic Energy Commission was held in New York on June 14, 1946. At this meeting Mr. Baruch, the United States representative, proposed:
the creation of an International Atomic Development Authority, to which should be entrusted all phases of the development and use of atomic energy, starting with the raw material and including—
(1) Managerial control or ownership of all atomic-energy activities potentially dangerous to world security.
(2) Power to control, inspect, and license all other atomic activities.
(3) The duty of fostering the beneficial uses of atomic energy.
(4) Research and development responsibilities of an affirmative character intended to put the Authority in the forefront of atomic knowledge and thus to enable it to comprehend, and therefore to detect, misuse of atomic energy. To be effective, the Authority must itself be the world’s leader in the field of atomic knowledge and development and thus supplement its legal authority with the great power inherent in possession of leadership in knowledge.
These United States proposals, which were unprecedented on the part of a world power in possession of a monopoly, did not come as a surprise to the other representatives on the Commission. This was because these United States proposals had for practical purposes been announced by the release of the so-called Acheson-Lilienthal Report some two months earlier. Thus the rejection of the Baruch plan by Russia, five days after it was proposed, could not be discounted as action taken in haste. The essence of the Russian counter-proposal is contained in the following paragraphs quoted from a speech of Mr. Gromyko before the United Nations Atomic Energy Commission on June 19, 1946:
The high contracting parties solemnly declare that they will forbid the production and use of a weapon based upon the use of atomic energy, and with this in view, take upon themselves the following obligations:
(a) Not to use, in any circumstances, an atomic weapon;
(b) To forbid the production and keeping of a weapon based upon the use of atomic energy;
(c) To destroy within a period of three months from the entry into force of this agreement all stocks of atomic energy weapons, whether in a finished or semi-finished condition.
The period from June through December, 1946, was spent in intensive discussion and examination of the Baruch plan by the United Nations Atomic Energy Commission and its Committees. On December 30, 1946, the Commission adopted a report embodying the Baruch plan by a vote of ten to none, with Russia and Poland abstaining. This report, which was transmitted to the Security Council on December 31, 1946, divides atomic energy operations into two categories with respect to supervision:
(a) For operations including mining, milling, refining, and the chemistry and metallurgy of natural uranium and thorium, management by the Authority is not necessary but it must have unrestricted access to all equipment and operations and facilities for independent weighing, assay, and analysis.
(b) For isotope separation plants and large nuclear reactors and associated chemical extraction plants, the management must be responsible to the Authority.
In order to ensure detection of clandestine activities the report of December 31 states among other things:
The international control agency will require broad privileges of movement and inspection, including rights to conduct surveys by ground and air. These privileges should, however, be very carefully defined to ensure against misuse.
On February 18, 1947, Mr. Gromyko, the Russian representative, proposed material changes in the provisions of the above report. These changes in the editorial opinion of the New York Times “would in effect tear the heart out of the plan recommended by the Commission.”
On March 5, 1947, Mr. Gromyko, speaking before the Security Council of the United Nations, recalled that on October 23, 1946, Generalissimo Stalin had said, “A strict international control is necessary.” However, Russian reaction to the form of control embodied in the Baruch plan is indicated by the following paragraphs of Mr. Gromyko’s speech:
The United States proposals on control proceed from the erroneous premise that the interests of other States should be removed to the background during the exercise by the control organ of its control and inspectorial functions. Only by proceeding from such fundamentally vicious premises, was it possible to come to the conclusion contained in the proposals submitted to the Atomic Energy Commission by the United States representative on the necessity of transferring atomic enterprises to the possession and ownership of the international organ which is to be charged with responsibility for the realization of control. A proposal of this sort shows that the authors of the so-called Baruch plan completely ignore national interests of other countries and proceed from the necessity of subordinating the interests of these countries to the interests actually of one country; that is, the United States of America.
It is easy to understand that the granting of such rights to control organs would mean a complete arbitrariness of these organs and, first of all, of those who would be in a position to command a majority in these organs. Granting such rights to control organs would give an easy opportunity for interference in the activities of the enterprises on the territory of one or another country, without any grounds for such interference. . . .
I have already pointed out that the proposal on granting to an international control organ the right to possess establishments for the production of atomic energy, and unlimited power to carry out other important functions connected with the ownership and management of the establishments and with the disposition of their production, would lead to interference by the control organ in the internal affairs and internal life of States, and eventually would lead to arbitrary action by the control organ in the solution of such problems as fall completely within the domestic jurisdiction of a State. I deem it necessary to emphasize that granting broad rights and powers of such a kind to the control organ is incompatible with the State sovereignty. Therefore, such proposals are unacceptable and must be rejected as unfounded. Not only do they not facilitate the solution of the problem of establishing strict and effective international control, but, on the contrary, they complicate the solution of this problem.
An observer trained in Nineteenth Century diplomacy might consider that the Russian disagreement with the Baruch plan indicated in the above remarks was so fundamental that further negotiations at this time would be futile, but post-World War II diplomacy and the crucial importance of achieving a solution are reflected in the action of the Security Council on March 10, 1947, in which the United Nations Atomic Energy Commission was “urged” by the Security Council: “in due course to prepare and submit to the Security Council a draft treaty or treaties or convention or conventions incorporating its ultimate proposals.”
The long-haul character of further negotiations toward international control of atomic energy was recognized by Senator Vandenberg, Chairman of the Senate Foreign Relations Committee and member of the Joint Committee on Atomic Energy, in his speech of April 3, 1947, on confirmation of the United States Atomic Energy Commissioners:
Mr. Lilienthal could not escape the many mandates of the bill in this direction even if he would, and he will never get a chance because his appointment runs only for 17 months; and unfortunately there is no possibility of international agreements dependably to outlaw atomic bombs, under adequate discipline against bad faith, within this time.3
While it is emphasized that the only real defense against atomic bombs is prevention of war, and the only sure defense against surprise atomic attack lies in effective international control, it would be folly for the United States and a disservice to Western civilization to plan for the future on anything but a thoroughly realistic basis.
Since we have just finished a five-year all- out world war, it would seem offhand that military planning, which in this age means national planning, would be fairly straightforward, at least for the coming generation. However, the advent of jet propulsion, guided missiles, and atomic energy has injected so many disturbing elements that planners— when they try to lean over backward to be objective and realistic—are faced by the difficulty that they do not know which way is backward.
In anticipating the effect of these and other new developments, they have the choice of what might be called the “blue” and the “rose-colored” crystal balls. The blue crystal ball philosophy would require a planner to assemble a group of the best informed scientists and development engineers in a particular field, and to base his plans on the collective opinion of this group. He would impose the requirement that their extrapolation into the future should be based only on discoveries and knowledge which are already possessed by man. Predictions made under these conditions will inevitably be pessimistic if the period extends beyond, say, five years, because they discount the unpredictable effect of discoveries yet to come.
On the other hand, a planner who uses the rose-colored crystal ball will go beyond present knowledge and attempt to take into account the effect of future discoveries. These predictions will be in error because of the inevitable tendency always to predict discoveries in accordance with the taste of the individual planner. It might be characterized as thinking ahead unembarrassed by facts.
In considering the effect of the atomic bomb upon military tactics and strategy, it should be borne in mind that the bomb was used at the end of World War II when Japan was already defeated at sea, industrially, and in the air. As an example, the only difficulty in the entire Hiroshima attack following the takeoff in the darkness of August 6, 1945, lay in the fact that 600 B-29’s were returning to the Marianas from a saturation attack of the previous evening. For practical purposes, in August, 1945, the air over Japan belonged to the United States. This should be borne in mind also when one is considering the psychological effect of the atomic bombing on the Japanese.
The above situation is in all probability far different from the one in which two fully armed atomic adversaries would find themselves at the beginning of a future war. In any future war, as in World War II, delivery of atomic bombs will be a major consideration. This problem has frequently been passed over lightly or solved by glib statements and proof by assertion. In the light of any developments known at the end of World War II, a supersonic V-2 rocket with an atomic warhead, once launched, could not be intercepted and destroyed. Thus, for ranges of less than five hundred miles it may be said that the elements of mechanisms already exist for push button atomic war.
When the bombing range is extended from hundreds to thousands of miles, the technical situation is radically altered. Using the blue crystal ball philosophy, it may be said that present scientific and engineering knowledge in the field of propulsion and control for guided missiles does not justify the expectation that intercontinental supersonic guided missiles will come in the 1950’s.
With regard to delivery by manned aircraft at extreme range and at transonic speeds, there is a fundamental difficulty in the propulsion system. This difficulty arises from the operation of two limitations imposed by Nature. First, in the transonic range (.85 to 1.4 times sound velocity), air resistance (drag) is proportional to something between the third and fifth power of the velocity; and in the supersonic range it is approximately proportional to the square of the velocity. Second, thrust which overcomes drag is proportional to the momentum, which is the product of the mass of air (gas) moved to the rear, and its velocity. In the case of propeller-driven aircraft, the mass of air is large and the velocity is low; in the case of jet-propelled aircraft, the mass of air is small and the velocity is large. The trouble lies in the fact that the energy or work done is proportional to mass times velocity squared. Thus the jet achieves high speed but is very expensive in miles per gallon.
It is apparent from the above that very long range transonic or supersonic bombers are practically barred under the blue crystal ball philosophy. These limitations of range do not, however, bar the development of transonic or supersonic intercepting vehicles, either manned or externally guided. In fact, the fair assurance that inter-continental attack can be intercepted provides a major justification for developing these instruments of defense.
If the planner of inter-continental super bombers has been handicapped by the tremendous energy (fuel) requirements which transonic or supersonic speeds impose, he may hope that substitution of nuclear fuel for chemical fuel will solve the problem.
However, there are several major difficulties in using nuclear fuel to propel manned or unmanned vehicles through the air:
(a) If human crews are carried, there is a major shielding problem. This arises from the fact that nuclear fission is a highly radioactive process giving rise to copious ejection of neutrons and unstable atoms which have alpha, beta, and gamma activity. Calculations made so far lead to the conclusion that a manned airplane propelled by nuclear energy would at least equal the weight of the B-36, and would probably weigh several times as much, in order to carry the shielding load,
(b) In order to achieve jet propulsion with nuclear power reactors, major problems including heat transfer, high- temperature metallurgy, and ceramics must be solved. Thermodynamic efficiency demands operation at the highest possible temperature. There is no theoretical limit to the temperatures which can be generated in a nuclear chain reaction (witness the bomb), but this heat must be transmitted to the gas through materials which must remain rigid. In the case of a chemical fire, the heat transfer is relatively simple since the combustion itself takes place in the moving gas.
(c) The heat transfer and high temperature considerations also apply to rocket propulsion. In addition there is the problem of providing momentum reaction (thrust) by a gas which is heated in the nuclear reactor. The lightest atoms give the best jet efficiency, so hydrogen will probably be chosen. In order to get inter-continental ranges with a nuclear powered rocket, many tons of liquid hydrogen would have to be carried. This is the space rocket of the Sunday supplements. It actually runs out of thrust as soon as the hydrogen supply is gone.
(d) A nuclear chain reaction differs from a chemical chain reaction (fire) in that it will not maintain itself unless there is at least one critical mass of active material present. If this were true in chemical combustion, a sub-critical coal pile would not burn under any circumstances; but if coal were added, it would smoke and burn spontaneously just as criticality was reached. This minimum nuclear fuel requirement means that each power reactor must contain a far-from-negligible fraction of the entire available amount of active material in order to “burn” at all. Thus scientists and engineers working toward nuclear powered flight face the bleak prospect that in the event that they achieve success in heat transfer and high temperature metallurgy, and have ready a prototype power reactor, the required shielding weight could prevent it from leaving the ground with a human crew, and the probability of loss of precious active material might prevent it from flying in a guided missile!
The above considerations apply generally to use of atomic power for ship propulsion. In this case the weight and space limitations are not so rigid and the ship designers have no hydrogen-fed jets to worry them. However, the best qualified experts have gazed long and hard into the blue crystal ball and have not seen nuclear powered ships in the middle 1950’s.
In general, in the first and second years of the Atomic Age the tendency has been to treat nuclear energy as the magic cure for every problem from cancer to war. Actually, nuclear fission has created ten problems for every one it has directly solved. One of the created problems is that loose or emotional thinking has been dignified by injecting the word “atomic” in every sentence.
As an example of pathological optimism, exaggerated claims have been made regarding atomic cure of cancer. The facts are summarized by Dr. C. P. Rhoads in a United States report to the United Nations Atomic Energy Commission as follows:
The two non-cancerous conditions—hyperthyroidism and polycythemia—are accessible today to treatment, the first with radioactive iodine and the second with radioactive phosphorus. The two cancerous conditions—thyroid cancer and cancer of blood-forming tissues—are not proved to be very accessible to cure or to control by the use of radioactive iodine in the first case or of radioactive phosphorus in the second case.
In the charged atmosphere of the fall of 1945, cure of disease, atomic power for general use within a few years, and “atomically” accelerated obsolescence of existing military equipment and tactical concepts were generally regarded as axiomatic. However, in many quarters it was clear that in redesigning military equipment we should start with the types in use or under development at the end of World War II, rather than with a push button alone.
The Joint Chiefs of Staff were keenly aware of this problem and formed a committee under General LeMay to recommend the kind and scope of tests in which naval vessels and other military equipment would be subjected to attack by atomic bombs. Out of the LeMay Committee’s recommendations, and the action on them by the Joint Chiefs of Staff, grew the concept of the Bikini tests. The actual plan for the tests and the name “Crossroads” were contributed by Vice Admiral (now Admiral) Blandy after he was appointed Task Force Commander. To Admiral Blandy also fell the major task of organizing Joint Task Force One to conduct Operation Crossroads, and reconciling the divergent and conflicting views of the many groups involved in conditioning the target ships and planning the target layouts.
The technical side of Operation Crossroads can be appreciated by picturing a colossal laboratory with about the same relation to a university laboratory that the atomic bomb has to a TNT bomb. The requirements for remote—or at least unmanned —control of all instrumentation can be appreciated when one thinks merely of the violence of an explosion of 20,000 tons of TNT. Added to this there was the potent radioactivity of the fission products, which was initially equal to 1,000 tons of radium.
It was considered to be absolutely necessary to subject actual target ships at full scale to this detonation rather than models or mere arrays of pressure gages, because actual ships are so complicated mechanically that mathematical predictions of their action under this prolonged impulse and shock would be unreliable. Furthermore, it was considered essential to load the ships with their normal explosive cargoes and with fuel and gasoline so that if the bomb would start chemical chain reactions in the form of fires and explosions in an actual fleet, it would do so also in the Bikini fleet.
Summing up the tests, I would say that both were valid, and that technical information of great value to military design and planning was obtained. The technical reports of the operation are now in the hands of the Joint Chiefs of Staff Evaluation Board. I believe the overwhelming—and to a certain degree unpredictable—result of the Bikini tests came from the underwater detonation of the bomb in Test Baker. None of the previous atomic bombs had been detonated underwater or underground, and it was not known what percentage of the fission fragments would remain on the ships and in the lagoon. The results of Test Baker demonstrated conclusively that the atomic bomb is not only a most terrible blast instrument but, detonated under water, it is also a deadly spreader of radioactive poison.
The conclusions of the Joint Chiefs of Staff Evaluation Board and the action of the Joint Chiefs of Staff on the report of the Bikini tests will guide the planners and designers of our Navy of the future. To attempt to anticipate or comment in advance on these conclusions would be improper and unwise. However, information already released paints the picture with a broad brush -—after all, an atomic bomb is hardly a subtle phenomenon! This picture in the setting of the mid-Twentieth Century atomic weapon and delivery situation outlined and discussed earlier is one of evolution rather than revolution. At least for the coming generation, use of the sea and therefore control of the sea will continue to be decisive.
With respect to the predictions as to technical progress, it is again emphasized that these predictions discount new discoveries. On the bright side, it is as certain as any human event that the new research tools which have come from scientific discoveries in the last fifteen years will, in the next fifteen years, give us basic discoveries in physics, chemistry, and biology. And we may hope that necessity will be the mother of invention in the field of international control of our actual and potential super weapons.
1. Equations
92U238+0n1—>92U239—>93Np239+-1e0
93Np239—>94Pu239+-1e0
90TH232 + 0n1—>90Th233—>91Pa233+-1e0
91Pa232—>92U233+-1e0
2. (Rutherford’s experiment)
2He4+7N14—>9F18—>8Ol7+1H1
3. Section 10(a)(1) of the U. S. Atomic Energy Act of 1946 reads as follows:
That until Congress declares by joint resolution that effective and enforceable international safeguards against the use of atomic energy for destructive purposes have been established, there shall be no exchange of information with other nations with respect to the use of atomic energy for industrial purposes.