“The core of the devil”: what the third atomic bomb that the US was preparing to drop on Japan was like (and the two fatal accidents it caused)

August 6 and 9, 1945 The United States dropped the only two nuclear bombs ever used in a war on Hiroshima and Nagasaki.

Together they were the most lethal attacks that have ever occurred, in which it is estimated that around 200, 000 people.

From the US perspective, they were aiming to press the surrender of Japan and end WWII.

And in case they weren’t enough, Washington had practically a third atomic bomb ready.

His nickname was Rufus, and it consisted of a plutonium core, similar to the one used in the Fat Man bomb, which detonated over Nagasaki.

Rufus never converted It was a functional bomb, but it did cause two fatal accidents, so it was recorded in history as “the core of the devil.”

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“It was essentially the same as the Fat Man nucleus,” Alex Wellerstein, historian specialist in nuclear weapons and author of the blog Nuclear Secrecy.

That means that it could have become a bomb capable of generating an explosion of about 20 kilotons, as happened in Nagasaki.

Sec In official US communications cited in an article by Wellerstein, a bomb made from Rufus should have been ready to drop as of 17 or 18 August 1945.

In the first days of August of 1945, it was not clear if two atomic bombs would be enough to subdue Japan, explains Wellerstein.

Only after his surrender on 15 August “it became clear that two bombs had been ‘enough ‘, but too much “, says the expert.

So finally it was not necessary to use Rufus .

“What happened between 15 and the 21 of August? I don’t know ”, writes Wellerstein, but what is documented is that as of 21 August, researchers at Los Alamos Laboratory in New Mexico, where the atomic bombs were designed, began using this plutonium core to extremely dangerous experiments.

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Tickle a dragon

In 1945, the only plutonium cores that had been manufactured were Rufus, Fat Man and the one who was placed in the Gadget bomb, which was used in the Trinity test, the first test of a nuclear explosion carried out by the United States.

In Los Alamos, the researchers They wanted to find out what the limit was at which plutonium became supercritical, that is, they wanted to know what was the point at which a plutonium chain reaction would unleash a explosion of deadly radiation.

The idea was to find more efficient ways to get a core to supercritical state and optimize the pump load.

Handling a plutonium core is an extremely delicate maneuver. That is why the researchers referred to these exercises as “tickling the tail of a dragon.”

“They knew that if they had the misfortune to wake up the furious beast , they would end up burned “, wrote the journalist Peter Dockrill in an article on the portal Science Alert.

According to explains Wellerstein, those who participated in these experiments were aware of the risk, but they did it because it was a way to obtain valuable data.

Lethal moments

Rufus’ first victim was the American physicist Harry Daghlian , which by then had 24 years.

Daghlian He had worked on the Manhattan Project, with which the US manufactured its first nuclear bombs.

The 21 August 1945 Daghlian set about building a stack of tungsten carbide blocks around Rufus.

His idea was to see if he could create a “neutron reflector” in which the neutrons launched by the nucleus would bounce and thus bring it more efficiently to the critical point.

It was night and Daghlian was working alone, violating security protocols, as documented by the portal Atomic Heritage Foundation.

The young scientist had already stacked several blocks, but when he was finishing placing the last one, his monitoring device told him that if he did so, the core could become supercritical.

It was like risking his life in an extreme game.

He maneuvered to remove the block, but unfortunately dropped it onto the core , which went into a supercritical state and generated a burst of neutrons.

Also, his reaction was to destroy the tower of blocks, so was exposed to a additional dose of gamma radiation.

Those moments were lethal.

During 25 days Daghlian endured the painful radioactive poisoning until he finally died at the hospital. It is estimated that you received one dose of 510 rem of ionic radiation.

The rem is the unit of measurement of the radiation absorbed by a person. On average, 500 rem are deadly for a human.

“That’s it”

Just nine months later the dragon attacked again.

The 21 May 1946 the American physicist Louis Stolin was practicing an experiment that he had done several times.

By then, Stolin was the world’s leading expert in handling dangerous amounts of plutonium, according to Wellerstein.

Along with a group of colleagues, he was showing how to bring a nucleus of plutonium -Rufus in this case- to the supercritical point.

The exercise consisted of joining two halves of a sphere of beryllium , forming a dome in which the neutrons will bounce towards the nucleus .

The key to not cause A disaster was to prevent the two half spheres from completely covering the nucleus.

To do this, Stolin used a screwdriver as a separator that served as escape valve for neutrons. That way he could record how increased fission , without the chain reaction reaching a critical point.

Everything was fine, but the only thing happened that shouldn’t happen.

Stolin slipped the screwdriver and the dome closed completely.

It was only an instant, but it was enough for the nucleus to reach the critical point and release a stream of neutrons that produced a intense blue glow.

“The blue flash was clearly visible throughout the room, even though it was well lit,” Raemer Schreiber, one of the physicists who was watching the experiment, wrote in a report.

“The flash did not last more than a few tenths of a second.”

Stolin reacted quickly and uncovered the dome, but it was too late : he had received a lethal dose of radiation.

Nine months before, he He himself had accompanied his colleague Daghlian during his last days of life, and it was clear to him that a similar fate awaited him.

“Well, that’s it”, were the first words he said, in all resigned , after he was the screwdriver will slip, as Schreiber recalls in his report, cited by Dockrill in Science Alert.

Estimates indicate that Stolin received in his body 2. 100 rem of neutrons, gamma rays and rays x.

His agony lasted nine days.

In that period suffered nausea, abdominal pain, weight loss and “mental confusion” , as described by Wellerstein in a magazine report The New Yorker.

Finally died at 35 years in the same room as l hospital in which his colleague Daghlian had died.

Ironically, Wellerstein points out, Stolin was doing the procedure for his colleagues to learn the technique in case he was not present.