image source, Getty
The first application of plutonium: the nuclear bomb.
Plutonium is perhaps the most feared element on the entire periodic table.
It is known to be the main ingredient in atomic bombs such as the infamous Fat Man dropped on Nagasaki on August 9, 1945, which ended up killing 70,000 people. Japan surrendered six days later, but the threat of nuclear annihilation trapped the world for decades in the Cold War.
However, the plutonium story is not all about Armageddon or the threat of the apocalypse. It also has to do with the incredible journey into the unknown.
You’ve probably heard or read the phrase “Houston we have a problem.” That’s what Commander Jim Lovell told NASA’s command center on Earth moments after Apollo 13 was rocked by an explosion.
It happened in April 1970 when the spacecraft already had 56 hours and 200,000 mission miles traveled. It was the third attempt by humans to land on the Moon.
One of the oxygen tanks had exploded, severely damaging the ship’s main power source and causing the temperature on board to drop dangerously and carbon dioxide levels to rise.
Lovell and his crew had to retreat to the lunar module that carried scientific instruments on board powered by a battery containing 8.5 pounds of pure plutonium.
That battery helped save the lives of astronauts.
Since then, plutonium has been key to several successful missions. The Voyager space probe contains batteries that still provide an estimated 300 watts of power a day, 200 less than when it was launched in 1977.
The Mars recovery vehicle also relies on the heat generated by the plutonium to keep its joints from freezing, and of course, to give it electricity.
Apollo 13 commander Jim Lovell carrying a stack of plutonium.
The battery works because the nucleus of plutonium is much bigger than any other natural element and that makes it unstable. If it breaks it produces radiation and also heat, which can be converted into electricity.
The plutonium in those batteries is not the same as the one in the atomic bombs, plutonium-239.
Plutonium batteries use a different isotope, plutonium-238, which has one fewer neutron in its nucleus and decays faster, has a life of 88 years, a fraction of the 24,000 years for plutonium-239, or 80 million. of plutonium-244.
But even 80 million years is much less when compared to the 4.5 billion years of our planet’s existence. That explains why only a few minute traces of plutonium-244 were still found on Earth… until 1940.
journey into the unknown
This was when another great journey into the unknown occurred, this time into the world of chemistry, into the “transuranium” elements.
“Uranium for a long time was seen as the end of the periodic table, the Ultima Thule“, explains Professor Andrea Sella of University College London, who uses a term from medieval geographers to refer to the confines of the unknown. “It was as far as you could go.”
That began to change in 1932 with the cyclotron, an invention of American scientist Ernest Lawrence, a device for accelerating particles around a circular chamber of electromagnets.
By impacting atoms and particles together, nothing more and nothing less than alchemy was achieved, transforming one element into another. What makes an element chemically unique is its number of protons in the nucleus. Add another proton and suddenly you have a new chemical.
Plutonium is now used for more peaceful applications.
This is how synthetic plutonium was created in December 1940.
A team led by radiochemist Glenn Seaborg used the cyclotron to bombard a uranium sample with deuterium, creating another element that Seabrog’s colleague Edwin McMillan had identified earlier that year: neptunium, as we now call it.
This disintegrates in two days giving life to another element: plutonium.
The Californian city of Berkeley looks a strange place to be the place where it was created. Sunscreens on eucalyptus trees stand out around a lab that hugs a hill above San Francisco Bay.
But in 1940 much of the world was at war and the race was on to create the deadliest weapon ever seen, the nuclear bomb.
new items
There was uranium, element 92, after the planet Uranus. Neptune, the next planet, which will end the name neptunium, element 93 and logically Pluto and element 94, plutonium.
Plutonium-239 atoms shoot out neutrons when they decay. It puts them close enough together and it sets off a chain reaction.
I had the honor of meeting nuclear scientist Heino Nitsche at Berkeley just days before he died on July 15.
image source, Scientific Photo Library
The cyclotron built by Ernest Lawrence at the Berkeley, California laboratory.
He wasn’t a big fan of nukes and compared plutonium to a mousetrap box full of ping-pong balls that you throw one more into to activate them.
The development of the atomic bomb was not the only investigation around plutonium, or the one that ended ethical questions.
In the 1990s, American journalist Eileen Welsome of the Albuquerque Journal won the Pulitzer Prize for bringing to light public studies commissioned by the country’s armed forces on the effects of exposing humans to radiation.
These include experiments carried out by the US military on people without their consent. Inmates and hospital patients were used as guinea pigs. In one experiment, radiation doses were given in the breakfasts of orphaned children.
Investigative reporter Peter Marshall reported these experiments to the BBC in 1994.
At one point, he said, a radioactive cloud 700 times above safe levels was released over the Hanford nuclear plant in Washington state.
The experiments were carried out in the dark period of the Cold War, Marshall explains, when US authorities were terrified of a possible nuclear conflagration.
Marshall was able to interview Glenn Seaborg, who was in charge of the Atomic Energy Commission that coordinated the radiation experiments.
Seaborg told him that he did not believe anyone on the commission was responsible for the experiments.
But beyond the ethical implications behind the radiation experiments, another door was also opened on the foundations of physics, which also revolutionized chemistry.
image source, Scientific Photo Library
Glenn Seaborg in 1946, five years before he won the Nobel.
Three research centers, Berkeley in California, Dubna in Russia and Darmstadt in Germany, compiled just to see how many new synthetic elements could be created using devices descended from the first cyclotrons.
A total of 24 new elements have been confirmed to date and another two await confirmation, so the periodic table now includes up to 118 elements out of the original 92.
The names of these new items reflect the concerns of the people who cool them.
berkelium, dubnium and darmstadius
Naturally there’s berkelium, dubnium and darmstadium, as well as livermorium, named after the Lawrence Livermore National Laboratory, which, among other things, makes sure the US nuclear arsenal doesn’t disintegrate too quickly.
Many have been named after great scientists: einsteinium, curium, fermium, mendelevium, bohrium, and rutherfordium.
Others, like americium, californium, and hassium (named after the state Darmstadt is in), have patriotic roots.
Glenn Seaborg was immortalized by element 106, seaborgium, which he considers an even higher honor than the Nobel Prize, which he won in 1951 with his colleague McMillan.
But now many elements are being used for more peaceful applications.
image source, Scientific Photo Library
Americium, one of the many new elements on the periodic table.
For example, scientists are using radioactive elements to help cure cancer.
They are also using experiments and other molecules to directly target cancer cells. The idea is that the radiation they emit destroys cells but does not penetrate further into the body and damage other organs.
This method appears to be especially effective in long-dose chemotherapy and can give people several years of extra life.
If anything, these apps are the fruit of an original effort that focused on creating the most destructive weapon on the planet.
As Professor Sella says: “What is interesting is the way in which these useful applications emerge from highly questionable research” that has been done in the past.
