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Caesium-137

3rd February, 2023 Science and Technology

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Context:

  • A Caesium-137 capsule lost in transit two weeks ago was discovered when a vehicle equipped with specialist detection equipment picked up the radiation.
  • The small, round and silver capsule containing radioactive caesium-137 went missing in transportation through Western Australia.

Cesium and Cs-137:

  • Cesium (Cs) is a soft, flexible, silvery-white metal that becomes liquid near room temperature, but easily bonds with chlorides to create a crystalline powder. The most common radioactive form of cesium is Cesium-137 (Cs-137).
  • Cs- 137 is also one of the byproducts of nuclear fission processes in nuclear reactors and nuclear weapons testing.
  • Caesium-137 was discovered by Glenn T. Seaborgand Margaret Melhase.

Caesium-137 Characteristics:

  • Caesium-137 has a relatively low boiling pointof 671 °C and is volatilized easily when released suddenly at high temperature, as in the case of the Chernobyl Nuclear Accident. With atomic explosions, it can travel very long distances in the air.
  • After being deposited onto the soil as radioactive fallout, it moves and spreads easily in the environment because of the high water solubility of caesium's most common chemical compounds, which are salts.
  • A Cs-137 atom emits radiation in the form of medium-energy gamma rays, and to a lesser extent, high-energy beta particles.
  • Caesium-137 has a half-life of approximately 30 years, which means that after a period of 30 years, the amount of Cs-137 will have halved due to radioactive decay. 

Applications of Cs-137:

  • Cs-137 is produced by nuclear fission for use in medical devices and gauges.
  • In larger amounts, Cs-137 is used in medical radiation therapy devices for treating cancer; in industrial gauges that detect the flow of liquid through pipes; and in other industrial devices to measure the thickness of materials, such as paper, photographic film, or sheets of metal.

Health Hazards:

  • External exposure to large amounts of Cs-137 can cause burns, acute radiation sickness.
  • Exposure to Cs-137 can increase the risk for cancer because of exposure to high-energy gamma radiation.
  • High levels of radioactive cesium in body can cause nausea, vomiting, diarrhea, bleeding, coma, and even death. This may occur after nuclear accidents or detonation of atomic bombs.

Model Question

Q. Due to its long half-life, Caesium-137 is most significant nuclide for the radiation exposure of the population after a nuclear accident. Comment. Also, throw light on the applications of Cs-137 in today’s world.

 

https://indianexpress.com/article/explained/explained-global/radioactive-capsule-lost-and-found-australia-8418556/