The Scientists Who Pee Plutonium

SCIENCE

Members of the exclusive UPPU Club lived and breathed radiation . . . literally. (War is Boring)

See the club’s group project here.

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

Manhattan Project scientists Louis Slotin and Herb Lehr help assemble the Trinity “Gadget”—the world’s first atomic bomb—in 1945. Once you know what you’re looking at, the big round bomb on the left is less evocative than the small, cylindrical “slug” sitting on the wooden crate on the right. That slug is made of uranium-238, and it’s heavy—hence the two-handled carrying mechanism. The uranium slug carried the plutonium sphere that ultimately reached “critical mass” and caused Trinity’s chain reaction—a nuclear explosion.  Photograph courtesy Los Alamos National Laboratory Archives. (CC BY-NC-ND 2.0)

Manhattan Project scientists Louis Slotin and Herb Lehr help assemble the Trinity “Gadget”—the world’s first atomic bomb—in 1945. Once you know what you’re looking at, the big round bomb on the left is less evocative than the small, cylindrical “slug” sitting on the wooden crate on the right. That slug is made of uranium-238, and it’s heavy—hence the two-handled carrying mechanism. The uranium slug carried the plutonium sphere that ultimately reached “critical mass” and caused Trinity’s chain reaction—a nuclear explosion. 
Photograph courtesy Los Alamos National Laboratory Archives. (CC BY-NC-ND 2.0)

Discussion Ideas

 

  • What was the Manhattan Project?

 

  • What is plutonium?
    • Plutonium is a silvery metal that reacts with many other elements. Its atomic number 94 and its atomic weight is 244. It’s expensive, rare, and powerful stuff.

 

  • OK, so plutonium is awesome. Why is there plutonium in the urine of some scientists who worked on the Manhattan Project?
    • Chemists, metallurgists, and technicians involved in the Manhattan Project routinely worked with and around plutonium. (And most, it should be stressed, were never exposed to high or dangerous doses.)
    • Most UPPU Manhattan Project scientists and engineers were exposed to traceable amounts of plutonium by breathing dust containing the element. According to the good folks at Los Alamos, “Approximately 5% to 25% of inhaled [plutonium] particles are retained by the body. Depending on particle size (the smaller the particle, the higher its risk to be retained) and chemical form (soluble forms are more easily absorbed by the blood), inhaled plutonium will remain lodged in the lung or lymph system, or it will be absorbed by the blood and delivered mainly to the liver or bones.”
    • In other words, in high enough doses, plutonium will settle in your body and be excreted as urine, along with water, salts, and waste products.

 

 

  • If radiation poisoning is lethal, why are these scientists still alive?
    • Members of the UPPU club had low-level exposure to plutonium and “the mortality rate for the group is about 50% lower than the national average.” (Note: This does not mean plutonium is good for you!) High-level exposure will likely result in an increased risk for lung cancer, and possibly bone and liver cancer.
    • The radioactive risks of plutonium may have been overstated—it doesn’t work like kryptonite on Superman. According to this fascinating article from Los Alamos Science, “Driven by knowledge of the possible harmful health effects of plutonium, scientists carefully warned the public about them and established procedures to protect the workers in plutonium-processing facilities. In fact, their care was so extreme that many believe it was the scientists themselves who promoted an overstated idea that became well known at the end of the 1940s: ‘Plutonium is the most toxic substance known to man.’”

 

  • Should I be worried about exposure to plutonium?
    • Not really. Although tiny, tiny amounts of plutonium exist in nature, it is, by definition, a “rare earth element.” Most plutonium on Earth is radioactive fallout from nuclear testing done in the last century. “From the Trinity Test in 1945 until atmospheric testing was banned in 1963, over 5 tons of plutonium were dispersed in the atmosphere in the form of small particles blown around the globe by the wind.” But this isn’t quite reason to worry:
      • Most of this plutonium dust fell into the oceans, and approximately 96% of that amount simply sank as sediment onto the ocean floors because plutonium is not readily soluble in seawater. The fact that plutonium dissolves very slowly in water also explains why the plutonium concentration in our oceans is low and will continue to be so.”
      • Minute amounts of plutonium settled in topsoil, although its chemical properties largely prevent it from being absorbed by plants.
    • There are two major—and very rare—ways to join the UPPU club.

 

  • Are any other substances radioactive?
    • Trick question! All elements have radioactive isotopes. Radioactive isotopes (also called radionuclides) have an imbalance of nuclear energy. This imbalance makes them unstable, emitting energy (radiation) as they undergo consistent, predictable radioactive decay.
    • The 38 so-called “radioactive” elements are those that lack any stable isotopes.

 

TEACHERS’ TOOLKIT

War is Boring: The Scientists Who Pee Plutonium

Nat Geo: 1945: Trinity Atomic Bomb Test

United States Nuclear Regulatory Commission: Backgrounder on Plutonium

US Department of Energy: The Manhattan Project

Los Alamos Science: Plutonium and Health: How Great is the Risk?

Wikipedia Featured Article: Trinity (nuclear test)

Wikipedia Featured Article: Manhattan Project

Wikipedia Featured Article: plutonium

6 responses to “The Scientists Who Pee Plutonium

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