Part One - The Uranium Bomb


Chapter One - 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 U235 (the scientific designation for enriched uranium, the type required to make a bomb - author's note) had been painted on the wrapping of a package, it would then be carried over...and stowed in one of the six vertical mine shafts." [i]
      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." [ii]
      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."iii
     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 that 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, that the uranium on board U-234 was enriched and therefore easily usable in an atomic bomb. The accepted history asserts there is no evidence that the uranium stocks of U-234 were transferred into the Manhattan Project, although recent suggestions have hinted that this may have occurred. And the traditional history asserts that 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 had 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.iv 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.v

  Hirschfeld's straightforward account of the uranium being "highly radioactive" - he later witnessed the storage tubes being tested with Geiger counters,vi - and labeled "U235" provides profoundly important information about this cargo.  U235 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 ULTRA encoder/decoder had allowed the Western Allies to intercept and decode German and Japanese 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 cortege 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.vii

  Two days later, while the Sutton was slowly 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,"viii 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."ix

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.x 

The reporters were allowed to take photographs of the people disembarking the boat when it landed, but no talking to the prisoners was permitted.xi  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 translatedxii by the office of Naval Intelligence, quickly triggering a series of events.  On the second page of the manifest, halfway down the page, was the entry "10 cases, 560 kilograms, uranium oxide." 

Whoever first read the entry and understood the frightening capabilities and potential purpose of uranium must have been stunned by the entry.  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 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.xiii

  The identification that the uranium was stowed in gold-lined cylinders and that it would become "sensitive and dangerous" when unpacked provides clear substantiation of radio officer Hirschfeld's assertion that the uranium was labeled with the title U235. Uranium that has had its proportion of the isotope U235 increased compared to the more common isotope of uranium, U238, is known as enriched uranium. 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 that the uranium on board U-234 was 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.xiv 

Mr. Larsen remembered that 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 the 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 raw uranium, rather than enriched uranium, be stored in gold containers, I asked?  Not likely, Mr. Larsen responded.  The value of raw 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,xv the cost of the U235 on board the submarine was somewhere in the neighborhood of $100,000 an ounce; by far the most expensive substance on earth.  The fact that the enriched uranium had 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 addition to the gold-lined shipping containers corroborating Hirschfeld's identification of the uranium as U235, the description of the uranium's characteristics when its container was opened also tends to support the conclusion the uranium was enriched.  Uranium of all kinds is not only corrosive, but it is toxic if swallowed. In its raw 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 raw uranium that 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.xvi  Much of the German raw 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 by apparently unprotected G.I.s.xvii Since then, more precautions have been taken in handling raw uranium, but at the time, caution was minimal and raw uranium was considered to be relatively safe.xviii  For the Navy to note the uranium would become "sensitive and dangerous" and should be "handled like crude TNT" when it was unpacked tends to indicate that the uranium enclosed was, in fact, enriched uranium. Uranium enriched significantly in U235 is radioactive and therefore should be handled with appropriate caution, as the communiqué described.

  By 16 June 1945, a second cargo manifest had been prepared for U-234, this time by the United States Navy.  But the uranium was not on the list.  It was not even marked as shipped out or having once been on hand.  It was never mentioned.  It was gone - as if it never existed.
  Where did the uranium go? Eleven days after U-234 was escorted into Portsmouth, and four days after Pfaff identified its location on the U-boat, a team was selected to oversee the offloading of U-234. Portsmouth received the following message:

Lieut. Comdr. Karl B Reese USNR, Lieut (JG) Edward P McDermott USNR and Major John E Vance CE USA [Corps of of Engineers, United States Army (the Manhattan Project's parent organization)  - author's note] will report to commandant May 30th Wednesday in connection with cargo U-234.

It is contemplated that shipment will be made by ship to
ordnance investigation laboratory NAVPOWFAC Indian
Head Maryland if this is feasible.xix

The order, dispatched by the chief of naval operations, is revealing if not outright startling for the selection of one member of its three-man team. Including Major Vance of the Army Corps of Engineers in what was otherwise an all Navy operation seems a telling selection.  The military services of the United States, as in most other countries, were highly competitive with one another.  True, U-234's cargo included a mixed bag of aeronautics, rocketry and armor-piercing technology that the Army could use, too, but the Navy had programs for all of these materials and surely would have done its own analysis first and then possibly shared the information with its service brothers.
  Someone, somewhere at a very high level, appears to have seen that the Army was brought into the scavenging operation that had become U-234; not just any Army group, but the group that oversees the Manhattan Project - the Corps of Engineers.

  Major John E. Vance was not only from the Corps of Engineers, the Army department under which the Manhattan Project operated, but, if a telephone transcript taken from Manhattan Project archives refers to the same "Vance" as the Major assigned to offload U-234 - as it appears to - then he was part of America's super-secret atomic bomb project, as well. The transcript is of a conversation between Manhattan Project intelligence officers Smith and Traynor and was recorded two weeks after "Major Vance" was assigned to the team responsible for unloading the material captured on U-234.

Smith: I just got a shipment in of captured material and there were 39 drums and 70 wooden barrels and all of that is liquid.  What I need is a test to see what the concentration is and a set of recommendations as to disposal. I have just talked to Vance and they are taking it off the ship and putting it in the 73rd Street Warehouse.  In addition to that I have about 80 cases of U powder in cases.  He (Vance) is handling all of that now.  Can you do the testing and how quickly can it be done?  All we know is that it ranges from 10 to 85 percent and we want to know which and what.

Traynor: Can you give me what was in those cases?
Smith:  U powder.  Vance will take care of the testing of that.

Traynor:  The other stuff is something else?
Smith:  The other is water.xx

U-234's cargo manifest reveals that, besides its uranium, among its cargo was 10 "bales" of drums and 50 "bales" of barrels.  The barrels are noted in the manifest to have contained benzyl cellulose, a very stable substancexxi that may have been used as a biological shield from radiation or as a coolant or moderator in a liquid reactor.xxii  The manifest lists the drums as containing "confidential material."  As surprising as it may seem, this secret substance may have been the "water" that Major Smith noted in his discussion with Major Traynor. Why would Major Smith want the water tested?  And what did he mean when he said that its concentration ranged "from 10 to 85 percent and we want to know which and what"?

  The leaders of the German project to breed plutonium had decided to use heavy water, or deuterium oxide, as the moderator for a plutonium-breeding liquid reactor.  The procedure of creating heavy water results in regular water molecules picking up an additional hydrogen atom.  The percentage of water molecules with the extra hydrogen represents the level of concentration of the heavy water.  Thus Major Smith's seemingly overzealous concern about water and his question about concentration is predictable if Smith suspected the material was intended for a nuclear reactor. And using heavy water as a major element of their plutonium breeding reactor project, it is easy to see why the Germans labeled the drums "confidential material."  The evidence indicates that U-234 - if the captured cargo being tested by "Vance" was from U-234, which seems very probable given all considerations - carried components for making not only a uranium bomb, but a plutonium bomb, also.

  Further corroborating the connection of the barrels and drums as those that were taken from U-234 is a handwritten note found in the Southeast national archives held at East Point, Georgia.xxiii  Dated 16 June, 1945, two days after Smith's and Traynor's telephone conversation, the note described how 109 barrels and drums - the exact total given in the Smith/Traynor transcript - were to be tested with geiger counters to determine if they were radioactive.  The note also included instructions that an "intelligence agent cross out any markings on drums and bbls. [sic. - abbreviation for barrels - authors note] and number them serially from 1 to 109 and make note of what was crossed out."  The note goes on to say that this recommendation was given to and approved by Lt.Colonel Parsons, General Groves' right-hand man on the military side of the Manhattan Project.  And lastly, the writer of the note had called Major Smith, apparently to report back to him, leading one to believe the note's author may have been Major Traynor.

  Was the captured cargo discussed by Smith and Traynor from U-234?  The presence of a Mr. "Vance" who was in charge of "U powder," almost certainly determines that such was the case.  The documents under consideration and the conversation they detail are from Manhattan Project files and are about men who worked for the Manhattan Project. Using the letter "U" as an abbreviation for uranium was widespread throughout the Manhattan Project.  That there could have been another "Vance" who was working with uranium powder - especially "captured" uranium powder - seems unlikely even for coincidence. 

And the fact that the contents of the barrels listed on the U-boat manifest were identified as containing a substance likely to be used in a nuclear reactor, benzyl cellulose, and that the barrels in the Smith/Traynor transcript and the untitled note - as well as the drums - were tested for radioactivity by geiger counter, certainly links the "captured" materials to no other source than U-234. The new-found evidence taken en mass demonstrates that, despite the traditional history, the uranium captured from U-234 was enriched uranium that was commandeered into the Manhattan Project more than a month before the final uranium slugs were assembled for the uranium bomb. 

The Oak Ridge records of its chief uranium enrichment effort - the magnetic isotope separators known as calutrons - show that a week after Smith's and Traynor's 14 June conversation, the enriched uranium output at Oak Ridge nearly doubled - after six months of steady output.[xxiv]  Edward Hammel, a metallurgist who worked with Eric Jette at the Chicago Met Lab, where the enriched uranium was fabricated into the bomb slugs, corroborated this report of late-arriving enriched uranium.  Mr. Hammel told the author that very little enriched uranium was received at the laboratory until just two or three weeks - certainly less than a month - before the bomb was dropped.[xxv] The Manhattan Project had been in desperate need of enriched uranium to fuel its lingering uranium bomb program.  Now it is almost conclusively proven that U-234 provided the enriched uranium needed, as well as components for a plutonium breeder reactor.



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