Critical Mass
The Real Story Of The Birth Of The Atomic Bomb And The Nuclear Age
by Carter P. Hydrick
1998
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.
Notes:
i Wolfgang Hirschfeld and Geoffrey Brooks, Hirschfeld:The Story of A U-boat NCO 1940-1946, pp. 198,199
ii US Archives NARA II, U-boat U-234 file, US Navy secret dispatch
#292045, 30 May 1945
iii US Archives Southeast Region, East Point, Georgia, telephone
transcript titled Telephone Conversation Between Major Smith, WLO and
Major Traynor, 14 June, 1945
iv US Archives NARA II, extract of intercepted transmission sent from
Chief Inspector in Germany to Bureau of Military Operations and Military
Affairs, #165, 15 April, 1945, declassified # NND975001, NARA date
9/15/97
v Wolfgang Hirschfeld and Geoffrey Brooks, Hirschfeld:The Story of A U-boat NCO 1940-1946, pp. 198,199
vi Wolfgang Hirschfeld and Geoffrey Brooks, Hirschfeld:The Story of A U-boat NCO 1940-1946, Appendix
vii US Archives NARA II, U-boat U-234 file, confidential dispatch #131509, 13 May 1945
viii US Archives NARA II, U-boat U-234 file, secret dispatch #151716, 15 May, 1945
ix US Archives NARA II, U-boat U-234 file, secret dispatch #151942, 15 May, 1945, declassified #NND745085
x US Archives NARA II, U-boat U-234 file, Log of Public Relations -
Restricted, by Commander N.R. Collier, 17 May, 1945; transcript,
Telephone Conversation Between Capt. V.D. Herbster, USN (Ret.), and
Commodore Kurtz, U.S.N. E.S.F., 18 May, 1945; second telephone
conversation transcript Captain Herbster and Commodore Kurtz, 18 May,
1945
xi US Archives NARA II, U-boat U-234 file, Log of Public Relations -
Restricted, by Commander N.R. Collier, 17 May, 1945; transcript,
Telephone Conversation Between Capt. V.D. Herbster, USN (Ret.), and
Commodore Kurtz, U.S.N. E.S.F., 18 May, 1945; second telephone
conversation transcript Captain Herbster and Commodore Kurtz, 18 May,
1945
xii US Archives NARA II, Manifest of Cargo For Tokio On Board U-234,
translated from German, 23 May, 1945, declassified #NND903015, NARA Date
12/11/93
xiii US Archives NARA II, secret dispatch #262151, 27 May, 1945
xiv Personal telephone conversation between the author and Clarence
Larsen, Director of Y-12 calutrons operations at Oak Ridge, no date
recorded
xv Joseph Borkin, The Crime and Punishment of I.G. Farben, p 116; Paul
Manning, Nazi In Exile, p.153; compare to Chapter Four, page 82
xvi Richard Rhodes, The Making of the Atomic Bomb, p. 427
xvii Richard Rhodes, The Making of the Atomic Bomb,p p. 608, 609
xviii Richard Rhodes, The Making of the Atomic Bomb, p. 461
xix US Archives NARA II, U-boat U-234 file, US Navy secret dispatch #292045, 30 May 1945
xx US Archives Southeast Region, East Point, Georgia, telephone
transcript titled Telephone Conversation Between Major Smith, WLO and
Major Traynor, 14 June, 1945
xxi Personal telephone conversation between the author and Dr. Susan
Frost, PhD, Associate Professor of Biochemistry and Molecular Biology,
College of Medicine, University of Florida, 30 August 1999, also Dr.
Wentworth, University of Houston
xxii Interscience Publishers, Concise Encyclopedia of Nuclear Energy, p. 688
xxiii US Archives NARA Southeast Region, East Point, GA, untitled handwritten note dated 6/16/45
xxiv US Archives NARA Southeast Region, East Point, GA, Beta Oxide Transfer Report; see also chart on page __
xxv Personal telephone conversation between the author and Edward Hammel, Manhattan Project metallurgist, 14 May, 1996
Bac