Critical Mass: How Nazi Germany Surrendered Enriched Uranium for the United States' Atomic Bomb
432
Critical Mass: How Nazi Germany Surrendered Enriched Uranium for the United States' Atomic Bomb
432Paperback(Third Edition, Third edition)
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Product Details
| ISBN-13: | 9781634241175 |
|---|---|
| Publisher: | Trine Day |
| Publication date: | 08/01/2016 |
| Edition description: | Third Edition, Third edition |
| Pages: | 432 |
| Sales rank: | 546,089 |
| Product dimensions: | 6.00(w) x 8.90(h) x 0.80(d) |
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Critical Mass
How Nazi Germany Surrendered Enriched Uranium for the United States' Atomic Bomb
By Carter Plymton Hydrick
Trine Day LLC
Copyright © 2016 Carter Plymton HydrickAll rights reserved.
ISBN: 978-1-63424-117-5
CHAPTER 1
U-234/U235
"The most important and secret item of cargo, the uranium oxide, which I believe was radioactive, was loaded into one of the vertical steel tubes [of German U-boat U-234]. ... Two Japanese officers ... [were] ... painting a description in black characters on the brown paper wrapping. ... Once the inscription U235had been painted on the wrapping of a package, it would then be carried over ... and stowed in one of the six vertical mine shafts."
– Wolfgang Hirschfeld, Chief Radio Operator of U-234
"Lieut Comdr Karl B Reese USNR, Lieut (JG) Edward P McDermott USNR and Major John E Vance CE USA will report to commandant May 30th Wednesday in connection with cargo U-234."
– US Navy secret transmission #292045 from Commander Naval Operations to Portsmouth Naval Yard, 30 May 1945
"I just got a shipment in of captured material. ... I have just talked to Vance and they are taking it off the ship. ... I have about 80 cases of U powder in cases. He (Vance) is handling all of that now."
– Telephone transcript between Manhattan Project security officers Major Smith and Major Traynor, 14 June 1945.
The traditional history of the atomic bomb accepts as an unimportant footnote the arrival of U-234 on United States shores, and admits the U-boat carried uranium oxide along with its load of powerful passengers and war-making materials. The accepted history also acknowledges these passengers were whisked away to Washington for interrogation and the cargo was quickly commandeered for use elsewhere. The traditional history even concedes two Japanese officers were onboard U-234 and that they committed a form of unconventional Samurai suicide rather than be captured by their enemies.
The traditional history denies, however, the uranium on board U234 was enriched and therefore easily usable in an atomic bomb. The accepted history asserted there was no evidence the uranium cargo of U234 was transferred into the Manhattan Project (although recent admissions acknowledged this occurred). And the traditional history asserts the bomb components on board U-234 arrived too late to be included in the atomic bombs that were dropped on Japan.
The documentation indicates quite differently on all accounts.
Before U-234 landed at Portsmouth – before it even left Europe – United States and British intelligence knew U-234 was on a mission to Japan and that it carried important passengers and cargo. A portion of the cargo, especially, was of a singular nature. According to U-234's chief radio operator, Wolfgang Hirschfeld, who witnessed the loading of the U-boat:
The most important and secret item of cargo, the uranium oxide, which I believe was highly radioactive, was loaded into one of the vertical steel tubes one morning in February, 1945. Two Japanese officers were to travel aboard U-234 on the voyage to Tokyo: Air Force Colonel Genzo Shosi, an aeronautical engineer, and Navy Captain Hideo Tomonaga, a submarine architect who, it will be recalled, had arrived in France aboard U-180 about eighteen months previously with a fortune in gold for the Japanese Embassy in Berlin. I saw these two officers seated on a crate on the forecasting engaged in painting a description in black characters on the brown paper wrapping gummed around each of a number of containers of uniform size. At the time I didn't see how many containers there were, but the Loading Manifest showed ten. Each case was a cube, possibly steel and lead, nine inches along each side and enormously heavy.
Once the inscription U235 had been painted on the wrapping of a package, it would then be carried over to the knot of crewmen under the supervision of Sub-Lt Pfaff and the boatswain, Peter Scholch, and stowed in one of the six vertical mineshafts.
Hirschfeld's straightforward account of the uranium being "highly radioactive" – he later witnessed the storage tubes being tested positively with Geiger counters – and labeled "U235" provides profoundly important information about this cargo. U is the scientific designation of enriched uranium – the type of uranium required to fuel an atomic bomb.
While the uranium remained a secret from all but the highest levels within the United States until after the surrender of U-234, a captured German Enigma encoder/decoder had allowed the Western Allies to decode intercepted German radio transmissions. Some of these captured signals had already identified the U-boat as being on a special mission to Japan and even identified General Kessler and much of his cortège as likely to be onboard, but the curious uranium was never mentioned. The strictest secrecy was maintained, nonetheless, around the U-boat.
As early as 13 May, the day before U-234 was actually boarded by the Sutton's prize crew, orders had already been dispatched that commanded special handling of the passengers and crew of U-234 when it was surrendered:
Press representatives may be permitted to interview officers and men of German submarines that surrender. This message applies only to submarines that surrender. It does not apply to other prisoners of war. It does not apply to prisoners of the U-234. Prisoners of the U-234 must not be interviewed by press representatives.
Two days later, while the Sutton was steaming toward Portsmouth with U-234 at her side, more orders were received. "Documents and personnel of U-234 are most important and any and all doubtful personnel should be sent here," the commander of naval operations in Washington, D.C. ordered. The same day, the commander in chief of the Navy instructed, "Maintain prisoners U-234 incommunicado and send them under Navy department representative to Washington for interrogation."
The effort to keep U-234 under wraps was only partially successful. Reporters had been allowed to interview prisoners from previous U-boats, and, in fact, were allowed to interview captured crews from succeeding U-boats, as well. When the press discovered U-234 was going to be off limits, a cry and hue went up that took two days to settle. Following extended negotiations, a compromise was struck between the Navy brass and the press core. The reporters were allowed to take photographs of the people disembarking the boat when it landed, but no talking to prisoners was permitted. When they landed at the pier, the prisoners walked silently through the gawking crowd and climbed into buses, to be driven out of the spotlight and far from the glaring eyes of history.
On 23 May, the cargo manifest of U-234 was translated, quickly triggering a series of events. On the second page of the manifest, halfway down the page, was the entry "cases, 560 kilograms, uranium oxide." Whoever first read the entry and understood the frightening capabilities and potential purpose of uranium must have been stunned. Certainly questions were asked. Was this the first shipment of uranium to Japan or had others already slipped by? Did the Japanese have the capacity to use it? Could they build a bomb?
Whatever the answers, within four days personnel from the Office of Naval Intelligence had brought U-234's second watch officer, Karl Pfaff – who had not been brought to Washington with the original batch of high-level prisoners but who had overseen loading of the U-boat in Germany – to Washington and interrogated him. They quickly radioed Portsmouth:
Pfaff prepared manifest list and knows kind documents and cargo in each tube. Pfaff states ... uranium oxide loaded in gold-lined cylinders and as long as cylinders not opened can be handled like crude TNT. These containers should not be opened as substance will become sensitive and dangerous.
The identification that the uranium was stowed in gold-lined cylinders and that it would become "sensitive and dangerous" when unpacked provides persuasive substantiation that this was U235 – enriched uranium – and not natural uranium. Uranium that has had its proportion of the isotope U increased compared to the more common isotope of uranium, U238, is known as enricheduranium. When that enrichment becomes 70 percent or above it is bomb-grade uranium. The process of enriching uranium during the war was highly technical and very expensive – it still is.
Upon first reading the uranium on board U-234was stored in gold-lined cylinders, this author tracked down Clarence Larsen, former director of the leading uranium enrichment process at Oak Ridge, Tennessee, where the Manhattan Project's uranium enrichment facilities were housed. In a telephone conversation I asked Mr. Larsen what, if anything, would be the purpose of shipping uranium in gold-lined containers. Mr. Larsen remembered the Oak Ridge program used gold trays when working with enriched uranium.
He explained that, because uranium enrichment was a very costly process, enriched uranium needed to be protected jealously; but because it is very corrosive, it is easily invaded by any but the most stable materials, and would then become contaminated. To prevent loss to contamination of the invaluable enriched uranium, gold was used. Gold is one of the most stable substances on earth. While expensive, Mr. Larsen explained, the cost of gold was a drop in the bucket compared to the value of enriched uranium. Would natural uranium, rather than enriched uranium, also be stored in gold containers? I asked. Not likely, Mr. Larsen responded. The value of natural uranium is, and was at the time, inconsequential compared to the cost of gold.
Assuming the Germans invested roughly the same amount of money as the Manhattan Project to enrich their uranium, which it appears they did, the cost of the U235 on board the submarine was somewhere in the neighborhood of $100,000 an ounce – in 1945 dollars – by far the most expensive substance on earth. The fact the enriched uraniumhad the capacity to deliver world dominance to the first country that processed and used it made it priceless. A long voyage with the U235 stowed in anything but gold could have cost the German/Japanese atomic bomb program dearly in contaminated enriched uranium.
Further inquiries revealed gold was not only good for withstanding the corrosive characteristics of uranium but added a secondary benefit as a logical choice for protection from a nuclear chain reaction within the enriched uranium, as well. While not the greatest of insulators from a chain reaction, gold absorbs neutrons at a relatively efficient rate. This is helpful especially for chain reaction-prone thermal neutrons that are often created when a neutron passes through water – a constant occurrence in the open mine tubes of a submarine, which is where the uranium tubes were stored. Neutrons passing freely through the cylinders could potentially have started a nuclear reaction. So besides shielding the uranium from contamination, the gold shield would also have helped insulate it from going critical.
The neutron-absorbing characteristic of gold, therefore, gave it an additional advantage as a deterrent from possible critical events within the U-boat.
Other substances, such as cadmium, are much better neutron absorbers but may not have been available to the Germans at the time.
In addition to the gold-lined shipping containers corroborating Hirschfeld's identification of the uranium as U235, the description for handling the cargo and of the uranium's characteristics when its containers were opened also indicates the uranium was enriched and not natural uranium. Uranium of all kinds is not only corrosive, but it is toxic if swallowed. In its natural state, however, which is 99.3 percent U238, the substance poses little threat to man as long as he does not eat it. The stock of natural uranium eventually was processed by the Manhattan Project originally had been stored in steel drums and was sitting in the open at a Staten Island storage facility. Much of the German natural uranium discovered in salt mines at the end of the war also was stored in steel drums, many of them broken open. The material was loaded into heavy paper sacks and carried from the storage area to waiting trucks by apparently unprotected G.I.s. Since then, more precautions have been taken in handling natural uranium, but at the time, caution was minimal and natural uranium was considered to be relatively safe.
For the Navy, therefore, to note the uraniumwould become "sensitive and dangerous" when the containers were opened, and should be "handled like crude TNT," is another indicator the uranium was, in fact, enriched. Uranium enriched significantly in U235 produces a much higher level of alpha radiation than natural uranium. Alpha radiation alone, however, is not harmful; it is barely powerful enough to penetrate the dead layer of skin all humans carry. This, in and of itself, poses no threat.
But alpha radiation – which is merely neutrons being released by the U235 – in a large enough body of enriched uranium so dense a significant quantity of neutrons strike other atoms, causing them to split and release their nuclear energy, may potentially generate lethal gamma radiation.
Opening multiple containers each holding sub-critical amounts of enriched uranium in close proximity to one another, therefore, could raise the quantity of free neutrons available from the combined U to approach a critical state, and possibly initiate a slow chain reaction and the gamma radiation that would be released with it. Preventing such a potential health hazard would be handled with appropriate caution, such as warning against opening the containers, and that the contents would be "sensitive and dangerous" when opened, as the communiqué described.
Detractors to the suggestion the uranium on board U-234 was enriched argue that warning the uranium was "sensitive and dangerous" referred to it being pyrophoric, not radioactive. Pyrophoria describes substances that have the capacity of self combusting. The phenomenon occurs when uranium has been reduced to its metal form and then ground or otherwise converted to a fine grain, then exposed to oxygen. But, as noted, this only occurs to uranium in its metallic state. Reduction to metal is the very last step that occurs in preparation for making a bomb. Uranium, raw or enriched, would not be stored or shipped in its metallic state for this reason.
The Manhattan Project intentionally converted its enriched uranium from tetraflouride form – its condition when processed through the beta calutrons – to tri-oxide for the express purpose of putting it in a stable ceramic state. The process is simple enough and certainly one the Germans would follow given the potential for disaster had they not. It is absurd to think they would ship 560 kilos of highly pyrophoric material of any kind anywhere, much less highly-valued uranium on a submarine loaded with near priceless cargo and intellectual capital in the form of important human beings, when this condition could be simply and inexpensively overcome. This is borne out by the fact literally every other reference to German uranium available – whether in the Salzburg mines, pitchblende from Joachimsthal or barrels bought from Union Miniére, states it was in oxide form.
Detractors to the enriched uranium idea forward other arguments against it, as well, such as if the uranium was highly enriched the gold lining in the cylinders would have melted. They assume this because of assumptions made in turn by Wolfgang Hirschfeld that the uranium was gamma radioactive. Hirschfeld reported witnessing high radiation readings when the tubes were checked with Geiger counters. He reasoned the uranium was highly radioactive because it was exposed in a reactor, creating gamma radiation. Those who have tried to negate his testimony have nevertheless adopted his erroneous reasoning – and a resulting non sequitur. They denounce the high levels of radiation report by citing the fact Germany had no reactors, which is true, and therefore there could be no high radiation levels, which is untrue.
"That the gold would melt if enriched uranium was stored in it is a croc," responded Dr. Delmar Bergen, retired director of the Nuclear Weapons Program at Los Alamos. He explained that his program used highly neutron-absorbing cadmium, which is 40 times more efficient absorbing neutrons than gold, but that it did not produce enough heat to cause the cadmium to melt. "Gold would be even less prone to melt," assured Dr. Bergen.
(Continues...)
Excerpted from Critical Mass by Carter Plymton Hydrick. Copyright © 2016 Carter Plymton Hydrick. Excerpted by permission of Trine Day LLC.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
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Table of Contents
Contents
Cover,Praise for Critical Mass!,
Title page,
Copyright page,
Dedication,
Author Carter Hydrick,
Author's Note to the Third Edition of Critical Mass,
Foreword,
Acknowledgments,
Introduction,
Prologue,
Part One,
The Uranium Bomb,
The German U-boat U-234,
U-234/U235,
General Leslie R. Groves,
The Two Billion Dollar Bet,
Uranium,
Baron Manfred von Ardenne, Professor Fritz Houtermans & Wilhelm Ohnesorge,
The Hidden Bomb,
Oak Ridge,
Part Two,
The Plutonium Bomb,
J. Robert Oppenheimer & General Groves,
Timing,
Hanford,
Simple Math,
Part Three,
Martin Bormann,
The crew of U-234,
Maiden Voyage,
Albert Speer, Martin Bormann & Adolph Hitler,
A Pig Digging For A Potato,
Operation Fireland,
The Pig Finds a Potato,
13) Escape,
Riddles,
The prize crew of the USS Sutton prepares to raise the U.S. flag over U-234,
Surrender,
Allen Dulles and Karl Wolff,
Occam's Razor,
Hiroshima,
Epilogue,
Sources,
Index,
Contents,
Landmarks,