The spark of the Super: Teller-Ulam and the birth of the H-bomb--rivalry, credit, and legacy at 75 years

[NNadir]

I'm not entirely sure the word "credit" is the correct one, but this case is important in nuclear history.

The spark of the Super: Teller–Ulam and the birth of the H-bomb—rivalry, credit, and legacy at 75 years

In early 1951, Los Alamos scientists Edward Teller and Stanislaw Ulam devised a breakthrough that would lead to the hydrogen bomb [1]. Their design gave the United States an initial advantage in the Cold War, though comparable progress was soon achieved independently in the Soviet Union and the United Kingdom.

The technical details of the design breakthrough remain classified. Instead of discussing the technology, here I present the story of the disputes that quickly followed its conception—particularly over who deserved credit. Teller and Ulam were brilliant, forceful, often difficult men who held little affection for each other [2,3]. Their contrasting accounts, alongside recollections from equally remarkable contemporaries, reveal how scientific breakthroughs emerge from a volatile mix of cooperation, competition, and flashes of independent insight.

These were not idle quarrels: Teller pointedly refused to cosign the hydrogen bomb patent—withholding shared recognition—and declined to attend the 1952 Ivy Mike test in the Pacific. His absence was interpreted (at least in part) as a protest stemming from Los Alamos Scientific Laboratory Director Norris Bradbury’s decision to keep Teller from directing the Mike engineering effort—an entirely justified call...

...The Teller–Ulam paper holds a place in fusion history comparable to the 1940 Frisch–Peierls memorandum for fission (as described in Cameron Reed’s excellent article in the July 2025 Nuclear News, “The Frisch-Peierls Memorandum: A Seminal Document of Nuclear History” [4–6]). The hydrogen bomb fundamentally changed the world’s geopolitics. It contained Soviet ambitions through the rapid expansion of nuclear arsenals and the military-industrial complex, underpinned strategies such as Massive Retaliation, influenced arms control agreements, and eventually helped shape a global nuclear order—embodied in the Treaty on the Non-Proliferation of Nuclear Weapons and the spread of peaceful reactor technologies. That order, however, has been under strain in recent years [7]...

"Under strain" is putting it mildly. It appears that a venal functional idiot suffering from dementia has some level of control of these weapons...

...Assessments of “who deserves credit” inevitably depend on whether one considers both phases of the solution: (1) Ulam’s initial concept and Teller’s radiation elaboration, and (2) Teller’s working out of the energetics. Both men, in their own retellings, acknowledged the two parts. Hans Bethe, in his detailed and fascinating history, also used this “two parts” framing [12]. Ultimately, any attempt to assign percentagesb is subjective.

The timeline was astonishing: just two and a half years from Truman’s directive to a full-scale thermonuclear test. It was even more extraordinary, in some ways, than the development of the fission bomb. The physics was more intricate; the computing tools were primitive, if trailblazing (ENIAC); and opportunities for experimental validation were limited. Its success was not assured. Unlike fission weapons, there were few intermediate tests to confirm progress. An exception came in 1951 with the Greenhouse George experiment, which produced the first sustained burning deuterium-tritium fusion plasma. Fuel was easier to obtain than fissile material but still demanded new industrial capacity, particularly for liquefying deuterium..

These bombs contain fissionable material, most likely plutonium (as well as tritium which must be replenished). Given that unstable beings can gain control of them, I do hope that sensible people, given the chance, will dismantle them and put the fissionable material to use to slow, if not stop, the death of the planetary atmosphere.

[LearnedHand]

1. I think Richard Rhodes' Dark Sun tells the history of this effor

Last edited Thu Feb 5, 2026, 12:05 PM - Edit history (1)

He definitely captures the rivalry and (for such giants of science) petty behavior.

[eppur_se_muova]

3. Rhodes is one hell of a writer. nt

[LearnedHand]

5. I saw him in person once

He signed my ratty copy of Making Of, which I’ve read like 3 times. He IS a hell if a writer.

[hunter]

2. There's an interesting reference in the bibliography of that paper...

... especially in regards to the handling of hydrogen for anyone interested in poking around the roots of the impractical "hydrogen as a motor fuel" concept.

It started with the hydrogen bomb.

The Untold Story of Building the First Megaton Thermonuclear Fusion Device: The Simple Element and IVY Mike

Abstract:

This report is a research and development engineer’s perspective on the fascinating story of the world’s first megaton-class thermonuclear device, IVY Mike (10.4 Mt). Few modern scientific endeavors have matched the complexity and breadth of scientific achievement in such a short amount of time as IVY Mike. This paper will take a look at the design, engineering, fielding, and execution of the world’s first megaton-class physics experiment by Los Alamos Scientific Laboratory and the birth of industrial liquid hydrogen use spawned by the Cold War effort. Although others have written on aspects of this technical history, they have not benefited from access to the original classified documents used by the present author. The present paper must necessarily omit some technical details that remain classified but represents the most comprehensive summary of the engineering and fabrication of the IVY Mike device in the open literature.

--more--

https://www.tandfonline.com/doi/full/10.1080/15361055.2025.2503035#abstract

The hydrogen bomb was "invented" at least three times, by the United States, the Soviet Union, and Britain. The greatest hurdle to overcome in building such a complex thing, of course, is knowing that it's possible.

The hush hush nuclear secrets! disclaimer in both these articles is rather quaint. The biggest hurdle any nation wanting to build a nuclear bomb has to overcome here in 2026 is having the intellectual and industrial infrastructure to do it, or having allies who are willing to share that capacity.

[eppur_se_muova]

4. Interesting article ! I knew ortho- and para-H2 existed, and could be separated, but didn't realized the isomerism

carried any drawbacks with it !

III. THE DEVELOPMENT OF INDUSTRIAL-SCALE LIQUIFIED HYDROGEN

III.A. Define the Problem and Research the Background

Liquid hydrogen has two isomeric forms at cryogenic temperatures: orthohydrogen and parahydrogen. Ordinary hydrogen liquifies at a ratio of 75% orthohydrogen to 25% parahydrogen. Over time, ordinary liquid hydrogen transforms to 99.8% parahydrogen in an exothermic reaction from orthohydrogen.[Citation11] As a result, ordinary liquid hydrogen/deuterium evaporates at a rate up to 20%/day until all the orthohydrogen exotherms to parahydrogen. The two isomers of hydrogen were known at the time of the project, but an effective catalyst to convert the orthohydrogen to parahydrogen was not known, despite active work on catalysts.[Citation12] Because of this, a large amount of work had to be performed to overcome the exothermic reaction and protect the precious liquified deuterium. This included the design, construction, and use of helium refrigerators. [An effective catalyst for volume production of parahydrogen was discovered by the National Bureau of Standards (NBS) in 1953, after Mike was detonated.][Citation13] Today, a mere 1% loss is considered acceptable.[Citation15]

[Igel]

6. This line's a bit problematic.

though comparable progress was soon achieved independently in the Soviet Union

Yes, the USSR achieved the H-bomb independently, if you count espionage as "independent research".

In much the same way that the PRC has managed to accelerate development, esp. "independently" acquiring IP from other countries.

[NNadir]

7. This is incorrect. Andrei Sakharov developed the first DELIVERABLE hydrogen bomb.

It has been reported that the Soviets were amused by the first American bomb, mocking it, since it was the size of a small house, relying on a considerable array of cryogenic devices. They obviously knew about it, but that knowledge was not critical to their success.

Sakharov also developed the Tokamak fusion reactor concept. When the temperatures reported for the reactor was announced by the Soviets, the British sent a delegation to Russia to confirm the numbers, since the Western world suspected the announcement was a propaganda type lie. The British confirmed the result.

The horror that Sakharov experienced after the Tsar Bomba nuclear test, to this day the largest nuclear weapon ever developed, caused him to become a dissident.

He was, besides his political activity, marking him as a great man especially considering what he surrendered to dissent, a truly great physicist, equal, and perhaps even better than the American physicists working on fusion systems.

It is true that Karl Fuchs, an important physicist who worked on the plutonium implosion project during the Manhattan Project, his work being critical to its success, was a communist and a Soviet spy, who aided the Soviet nuclear program, expediting it but not critical to preventing it.

Russia, Britain and France all developed nuclear weapons largely independently, although British scientists (Fuchs was a British citizen), played key roles in the Manhattan project, and didn't have far to go.

One can now learn on the internet how to make a nuclear weapons; the restriction being access to materials, not military secrets. There really aren't all that many nuclear weapons secrets, and probably never really were. Anyone with the resources to do it, could. There are many papers published in the scientific literature discussing weapons design, notably, those by Kessler et al on how to denature plutonium to make it useless for nuclear weapons.