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Mon Jun 10, 2019, 04:18 PM

The Nazis almost built a working nuclear reactor.

Tracking the journey of a uranium cube

The world entered the nuclear age when the Trinity bomb was detonated on 16 July 1945 near Alamogordo, New Mexico. The origin of the age can be traced back through a small uranium metal cube and 663 others like it. The Manhattan Project and the immense power unleashed by the weapons it produced were created in response to fears that scientists in Nazi Germany were working on their own weapon. The cube, a component of the “reactor that Hitler tried to build,” represents the Germans’ failed endeavor that catalyzed the nuclear age.

Some questions remain. How did a piece of uranium from Germany end up in Maryland 70 years later? How many like it are out there? What happened to the rest? Who is Ninninger? Years of research into the cube and its history has revealed a complex, intriguing, and incomplete story. From our research, we have uncovered some new information about the German nuclear program itself: The Germans could have built a nuclear reactor.

--more--

https://physicstoday.scitation.org/doi/10.1063/PT.3.4202


Had the Germans succeeded they were still a long way from building a bomb. Breeding and refining plutonium, or separating uranium 235 from natural uranium were still problems requiring formidable resources, as was building an implosion type bomb.

The Nazis had none of those resources when the B-VIII heavy water reactor was built.

Unaware of the immense progress the Manhattan Project had made, the Germans hoped that though they were almost certainly going to lose the war, they would be able to salvage the reputation of their physics community by being the first to achieve a self-sustaining nuclear reactor.


It's interesting that the Reich Minister for Armament and Ammunition, Albert Speer, had released German stocks of uranium in the summer of 1943 for use in non-nuclear ammunition. Uranium is still used in armor-piercing projectiles. Many parts of Iraq are still contaminated with Uranium used in our war to overthrow Saddam Hussein.

It's also interesting that even though Germany realized they probably didn't have the resources to build atomic bombs, they were still imagining things like nuclear powered submarines.

https://en.wikipedia.org/wiki/German_nuclear_weapons_program

I've always been keenly aware of ethical questions in science and engineering. One of my grandfathers was an Army Air Corp officer in World War II, the other grandfather a Conscientious Objector who had agreed to build and repair ships for the Merchant Marine rather than go to jail.

My Army Air grandfather never flew, which was a good thing because he was a bit of a klutz, probably somewhere on the autistic spectrum, but he did mysteriously acquire a knack for exotic metals during the war, and was hired by the aerospace industry when the war ended. I think he saw the war as a dirty business that needed to be done. Nazi Germany and Imperial Japan must not prevail. (My other grandfather had a similar opinion, which is probably why, even though he was a pacifist who would not take up arms, he chose work in the shipyards over prison.)

My Army Air grandfather was taciturn about military work, partly I assume because much of it was still classified, but partly out of some kind of humility. The last job he had before he retired was working for the Apollo Project. He was immensely proud of that work and would always talk about it.

I like to imagine that my grandfathers wouldn't have aggressively applied their talents to the war effort had they been on the other sides, in Germany or Japan. In that case I wouldn't be here. It's likely that my engineer grandfather would have been killed on some battlefield, and that my pacifist grandfather would have died as a dissident in some horrible manner. My ancestors didn't come to America in the 19th century for the opportunity, they came because the Europe they knew was a dangerous place for political and religious dissidents. Later, atomic scientists like Albert Einstein and Enrico Fermi came here for similar reasons.

Returning to the article I posted, don't you think it was a bit late in 1944 to be worrying about the "reputation" of German Physics?

Are there scientists today working under similar assumptions as the builders of the B-VIII heavy water reactor? If so, in what fields of science?

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Arrow 21 replies Author Time Post
Reply The Nazis almost built a working nuclear reactor. (Original post)
hunter Jun 2019 OP
Wellstone ruled Jun 2019 #1
hunter Jun 2019 #5
Wellstone ruled Jun 2019 #7
The Velveteen Ocelot Jun 2019 #2
hunter Jun 2019 #8
zipplewrath Jun 2019 #3
hunter Jun 2019 #4
SCantiGOP Jun 2019 #6
hunter Jun 2019 #10
Javaman Jun 2019 #16
zipplewrath Jun 2019 #11
localroger Jun 2019 #9
zipplewrath Jun 2019 #12
Javaman Jun 2019 #18
hunter Jun 2019 #15
localroger Jun 2019 #20
Javaman Jun 2019 #17
SCantiGOP Jun 2019 #13
Javaman Jun 2019 #19
localroger Jun 2019 #21
NNadir Jun 2019 #14

Response to hunter (Original post)

Mon Jun 10, 2019, 04:30 PM

1. Was not the distruction

of a Heavy Water production plant the main reason this project never made it to the testing state. Our College Physic's Text Book mentioned something along that line.

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Response to Wellstone ruled (Reply #1)

Mon Jun 10, 2019, 06:10 PM

5. I was thinking this as well, but now it seems it was more of an organizational problem.

They had enough uranium, they had enough heavy water, but not all in one place. They weren't willing to put all their eggs in one basket.

Boron free nuclear graphite, as used by the U.S.A. and later the Soviet Union might have been beyond Germany's means even if their physicists had recognized the problem. Removing the boron from German coal derived graphite wouldn't have been easy, and the diversion of coal required to accomplish it from the coal powered war machine would have been a very hard sell.

Nevertheless, "writing as late as 1947, Heisenberg still did not understand that the only problem with graphite was the boron impurity."

The U.S.A. and the Soviet Union had abundant sources of energy and boron free carbon.

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Response to hunter (Reply #5)

Mon Jun 10, 2019, 06:44 PM

7. Forgot about the Boron

contamination. Been 60 years since the days of being a lab rat. If you don't use it you do lose it.

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Response to hunter (Original post)

Mon Jun 10, 2019, 04:31 PM

2. There's a fascinating TV miniseries, The Heavy Water War,

about some aspects of the program. I think it's on either Netflix or Amazon Prime.

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Response to The Velveteen Ocelot (Reply #2)

Mon Jun 10, 2019, 07:16 PM

8. I'll look for it.

Seems it's no longer on U.S.A. Netflix, so I'll have to look elsewhere.

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Response to hunter (Original post)

Mon Jun 10, 2019, 04:35 PM

3. Depleted uranium

Uranium is still used in armor-piercing projectiles. Many parts of Iraq are still contaminated with Uranium used in our war to overthrow Saddam Hussein.


Depleted uranium is used for those bullets (among other things). The germans wouldn't have had the technology to separate it out from the other isotopes.

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Response to zipplewrath (Reply #3)

Mon Jun 10, 2019, 05:28 PM

4. Depleted uranium is used because there are huge stockpiles left over from uranium enrichment.

Natural uranium works as well in armor piercing projectiles. It's all about chemistry and density, nothing nuclear.

Uranium is toxic as a heavy metal, like lead or mercury.

By ethical measures there's not much difference between natural uranium projectiles or depleted uranium projectiles.

In a society that accepted nuclear power depleted uranium might be used as fuel for nuclear power plants. In that case it would be absurd to use depleted uranium in munitions since each gram of it has the potential energy of a few million grams of burning coal.

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Response to hunter (Original post)

Mon Jun 10, 2019, 06:42 PM

6. One of my Dad's favorite jokes

“If the war had lasted another year, the Germans would have had The Bomb —- dropped on them.

He was always very supportive of Truman using the bomb in Japan. He was a Marine pilot in the Pacific, and because of the extra planes and pilots that were being freed up by the end of fighting in Europe, his group had already been told that they would likely be retrained for tanks to take part in the assault on mainland Japan. Some estimates were that that invasion could cost 1 million US lives and 10 million Japanese.

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Response to SCantiGOP (Reply #6)

Mon Jun 10, 2019, 08:15 PM

10. Every "alternative history" following the success of the Trinity Test is moot.

The U.S.A. would have kept dropping atomic bombs on Japan until they surrendered or there was nothing left of Japan. Instantly, after the successful Trinity Test, one million American lives were no longer at stake.

The U.S.A. didn't stop with the plutonium bomb that destroyed Nagasaki. We built more than 100 "Fat Man" type bombs before 1950 and only quit building them because we had better bombs.

In too many disturbing ways the destruction of Nagasaki was an experiment. Some factions in the U.S.A. wanted to see what these plutonium bombs could do.

U-235 gun bombs, like the bomb that that destroyed Hiroshima, were too expensive, and just too damned scary as weapons. They could go off by accident. Oops. Mushroom cloud. One less military base.

But mostly it was the money.

Many people don't recognize the scale of the Manhattan Project. The goal shifted, from fighting an all-out nuclear war with Germany to world domination.

Thus the subsequent horror when other nations, starting with the Soviet Union, built their own bombs.

They would have done it anyways, even without espionage. That's the way science works.

You ask the right question, you do the right experiment, and you get your answer.


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Response to hunter (Reply #10)

Tue Jun 11, 2019, 08:54 AM

16. "The U.S.A. would have kept dropping atomic bombs on Japan until they surrendered"

Exactly right. Sounds like you know full well about Operation Downfall.

An A-bomb was to be used at each of the 3 landing zones in prepperation for the invasion landings. And that was just the start.

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Response to SCantiGOP (Reply #6)

Mon Jun 10, 2019, 08:38 PM

11. Caution

"Some estimates" had the casualties for the airborne in Normandy on D-day at 80%. We didn't get anywhere near that.

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Response to hunter (Original post)

Mon Jun 10, 2019, 08:00 PM

9. This is all well documented by Richard Rhodes

...in The Making of the Atomic Bomb. The Germans didn't know at the time their carbon was contaminated with boron, so mistakenly came to the conclusion that carbon couldn't be used as a moderator at all, and yes, the British bombed the Norsk Hydro heavy water plant in Norway and sank the last ferry out at our behest to deny them that approach. So they didn't "almost" build a reactor; they built a test article that never came close to sustaining a reaction, and they didn't have the resources to build an expanded version. It didn't help that they had chased away many of their best physicists for the crime of being Jewish. They did have a fair stockpile of uranium on hand which ended up being processed through US production plants to make plutonium after we captured it.

You will also sometimes hear such "almost had a reactor/bomb" claims about the Japanese, but while they had a couple of people who were aware of the possibility of atomic energy their feeble efforts in that direction were even more laughable and hopeless than the Germans'.

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Response to localroger (Reply #9)

Mon Jun 10, 2019, 08:47 PM

12. It's harder than one thinks

Nuclear reactors are harder to build than people understand. And at the time no one really understood how to do it. We had some of the literally smartest people in the world here (because the Germans chased many of them out of Europe) and we still almost killed huge numbers of people. The Chicago reaction almost got out of control. Several people died at Los Alamos when experiments went badly wrong.

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Response to zipplewrath (Reply #12)

Tue Jun 11, 2019, 08:59 AM

18. I remember when I first read about this, still amazes me that it was allowed to happen...

https://en.wikipedia.org/wiki/Demon_core

On May 21, 1946,[11] physicist Louis Slotin and seven other Los Alamos personnel were in a Los Alamos laboratory conducting another experiment to verify the closeness of the core to criticality by the positioning of neutron reflectors. Slotin, who was leaving Los Alamos, was showing the technique to Alvin C. Graves, who would use it in a final test before the Operation Crossroads nuclear tests scheduled a month later at Bikini Atoll. It required the operator to place two half-spheres of beryllium (a neutron reflector) around the core to be tested and manually lower the top reflector over the core using a thumb hole on the top. As the reflectors were manually moved closer and farther away from each other, scintillation counters measured the relative activity from the core. The experimenter needed to maintain a slight separation between the reflector halves in order to stay below criticality. The standard protocol was to use shims between the halves, as allowing them to close completely could result in the instantaneous formation of a critical mass and a lethal power excursion. Under Slotin's own unapproved protocol, the shims were not used and the only thing preventing the closure was the blade of a standard straight screwdriver manipulated in Slotin's other hand. Slotin, who was given to bravado, became the local expert, performing the test on almost a dozen occasions, often in his trademark blue jeans and cowboy boots, in front of a roomful of observers. Enrico Fermi reportedly told Slotin and others they would be "dead within a year" if they continued performing the test in that manner.[12] Scientists referred to this flirting with the possibility of a nuclear chain reaction as "tickling the dragon's tail", based on a remark by physicist Richard Feynman, who compared the experiments to "tickling the tail of a sleeping dragon".[13][14]

On the day of the accident, Slotin's screwdriver slipped outward a fraction of an inch while he was lowering the top reflector, allowing the reflector to fall into place around the core. Instantly there was a flash of blue light and a wave of heat across Slotin's skin; the core had become supercritical, releasing an intense burst of neutron radiation estimated to have lasted about a half second.[6] Slotin quickly twisted his wrist, flipping the top shell to the floor. The heating of the core and shells stopped the criticality within seconds of its initiation,[15] while Slotin's reaction prevented a recurrence and ended the accident. The position of Slotin's body over the apparatus also shielded the others from much of the neutron radiation, but he received a lethal dose of 1,000 rad (10 Gy) neutron and 114 rad (1.14 Gy) gamma radiation in under a second and died nine days later from acute radiation poisoning. The nearest person to Slotin, Graves, who was watching over Slotin's shoulder and was thus partially shielded by him, received a high but non-lethal radiation dose. Graves was hospitalized for several weeks with severe radiation poisoning and developed chronic neurological and vision problems as a result of the exposure.[8] He died 20 years later, at age 55, of a heart attack. It may have been caused by hidden complications from radiation exposure, but could also have been genetic in nature, as his father had died from the same cause.[16][17][18]

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Response to localroger (Reply #9)

Tue Jun 11, 2019, 01:42 AM

15. To quote from the article posted:

The reactor core as designed would not have been able to achieve a self-sustaining nuclear chain reaction given the amount of uranium and its configuration. But the design might have worked if the Germans had put 50% more uranium cubes in the core.


They had the uranium, they just didn't know what they were doing.

"Laughable" is misinformation.

Building a working reactor is not easy, but there was also a very strong incentive not to let anyone else know how much uranium, heavy water, and boron free graphite might be required to accomplish it.

The first Soviet reactor, the F-1, which operated from December 25, 1946 until November 2016, was designed with the expectation it would require much more uranium than was actually required.

Fermi had likewise overestimated (but not the the same extent) the amount of uranium required for Chicago Pile 1, which was the first human-made self-sustaining nuclear chain reaction on December 2, 1942.

In some alternate universe maybe Germany did build a successful uranium / heavy water / aircraft cable nuclear reactor, but that would have been only the first very small step towards a working plutonium bomb.

But it's not really "laughable" as judged by other nations that have built atomic weapons.

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Response to hunter (Reply #15)

Tue Jun 11, 2019, 05:07 PM

20. Actually it was laughable

The Germans had plenty of uranium (we made good use of it after capturing it) but they had no more heavy water nor any other critical materials necessary, nor any way to make use of the energy produced. Even if it had worked it would have been only a first experimental step like CP-1, and they had no resources to continue research. I once saw it stated that the only reason they were bothering was to salvage the reputation of German science once the war was well and truly lost.

If they had been able to pursue carbon as a moderator, or if they had not been denied isotope separation by the fact that the single means they had the resources to try didn't work with uranium hexaflouride, and most importantly if Hitler hadn't gotten the whole country bogged down in Russia in the winter with Operation Barbarossa, then there might have been a non-laughable chance of the Germans getting some kind of effective nuclear technology. As it was, just a useless waste of resources they would have gotten more benefit from directed toward some more practical element of the war -- much as with the V-weapons and jet aircraft which were never effective enough to justify their high costs.

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Response to localroger (Reply #9)

Tue Jun 11, 2019, 08:55 AM

17. that was such a brilliant book. Probably my favorite. nt

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Response to hunter (Original post)

Mon Jun 10, 2019, 08:51 PM

13. The real irony

Is that the US would have never built a usable bomb as quickly as they did without the Jewish scientists who fled Germany and other European nations to escape the Nazis.

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Response to SCantiGOP (Reply #13)

Tue Jun 11, 2019, 09:03 AM

19. I read a lot of alt history and I always wondered...

if hitler hadn't been the genocidal maniac that he was and didn't kill 6 million Jews plus another 4 million non-Jews but instead embraced them as the fellow human beings, how different the world would have been today.

still a fascist but not a genocidal fascist.

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Response to Javaman (Reply #19)

Tue Jun 11, 2019, 05:09 PM

21. Many Russians were willing to embrace the Germans as saviors

...until the Germans started massacring them, of course.

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Response to hunter (Original post)

Mon Jun 10, 2019, 09:56 PM

14. In 1943, after his famous meeting with Heisenberg, Neils Bohr escaped Denmark to England...

...an eventually made is way to Los Alamos where he drew a diagram of the German nuclear technology about which Heisenberg told him.

The American/British/Hungarian/German scientists found it amusing, and realized immediately it wasn't a bomb at all.

The Alsos mission found the reactor, which was basically along the lines of an early CANDU, and concluded it wouldn't work all that well.

Overall, the Americans found the German efforts laughable.

The Japanese also had a nuclear weapon program, but like Germany had nothing like the resources to see it through. The program that did succeed began as a British project, when impounded "Enemy Aliens" Otto Frisch and Rudolf Peierls, at British request, calculated the correct (more or less) critical mass of U-235 to make a bomb. In 1942, the British program was way ahead of the Americans, but certainly lacked the resources to see the matter through.

Bohr was stunned at the scale of the American effort, but was considered by Leslie Groves to be nothing more than a thorn in his side.

The debate has long been whether Heisenberg was incompetent to build a bomb or reactor, or whether he was deliberately sabotaging the effort.

I go with the former.

For the Nazis to build either a reactor or a bomb, they would need "Jewish Physics" which Heisenberg knew quite well but couldn't necessarily acknowledge, but he was never really the equivalent of Fermi, not even close. Although a great theoretician, Heisenberg lacked the experimental abilities that Fermi showed.

I saw Fermi's reactor last week at ORNL on the AMSE tour. It's a graphite machine, quite large, quite primitive, but it ran for 20 years.

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