Plutonium explainer

Officials have detected plutonium in multiple locations around Japan’s crippled Fukushima nuclear facility.

Tokyo Electric Power Co. said in a statement that the plutonium was discovered Monday in five locations around the plant.

The discovery of plutonium is just the latest in a string of misfortunes, after radiation leaking from the facility has been detected in vegetables, raw milk and tap water as far away as Tokyo.

Safety officials say the amount of plutonium found does not pose a risk to humans, but critics say the finding supports suspicions that dangerously radioactive water is leaking from damaged nuclear fuel rods.

As the situation at Fukushima worsens we take a closer look at plutonium.

What is plutonium?

Plutonium is a silvery-grey, radioactive metal. Its chemical symbol is Pu and its atomic number is 94.

It was discovered in 1941 by Glenn Seaborg, Edwin McMillan, Joseph Kennedy, and Arthur Wahl.

Plutonium is man-made, and is created from uranium in nuclear reactors.

There are 16 isotopes of plutonium, having mass numbers ranging from 232 to 247. Plutonium-239 is the isotope used in nuclear weapons and nuclear reactors.

Plutonium-239 is used in nuclear weapons because it is among the few materials whose atoms can be split to create a nuclear explosion. When Plutonium-239 atoms are split (or “fissioned”) massive amounts of energy are instantly released.

Approximately 110 tonnes of Plutonium-239 are generated each year in nuclear power plants across the globe.

Plutonium’s half-life

Plutonium remains radioactive for very long time. It decays by releasing small amounts of energy over time. The radioactivity level of an isotope is determined by its half-life, or the amount of time it takes for half of the original quantity of the isotope to decay. Plutonium-239 has a half-life of 24,100 years.

Plutonium risks

Because plutonium is radioactive, it is difficult to handle and store. Plutonium reacts with carbon, halogens, nitrogen and silicon. When exposed to air, plutonium gets very hot and can spontaneously ignite. Because plutonium easily fissions, it cannot be stored in large quantities. Storing more than a few pounds of plutonium in close proximity to each other could cause a nuclear chain reaction that ends in large amounts of radiation to be released into the atmosphere.

When plutonium remains outside of the human body, it generally does not pose a health risk. However, when inside the human body plutonium is toxic and can damage living tissue, cause radiation sickness and cancer.

The most common ways plutonium enters the body is through inhaling contaminated air, or ingesting contaminated food or water. Exposure to plutonium through inhalation poses a much bigger health risk than when ingested.

Plutonium is not easily digested by the stomach, therefore when plutonium is ingested it is generally passed out of the body.

However, when plutonium particles are inhaled they can become lodged in lung tissue and continue to give off radiation internally for years. The particles can also enter the bloodstream and travel to the liver, bone or bone marrow. If plutonium particles reach internal organs they can remain there for decades, continually damaging the surrounding tissue.

Being one of the heavier elements, plutonium isn’t able to travel as far through the air, meaning dangerous plutonium particles are unlikely to reach Canada’s coast.