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Name: Aamir
Status: student
Age: 20s
Location: N/A
Country: N/A
Date: 1999 

What is the lifetime of a nuclear bomb?

I was told that because Uranium decays, the bomb becomes a dud if its fuel is not replishned.

The useful lifetime of nuclear weapons is not known. Uranium is not much of a problem, as its decay process (half-life = 500 million years) is very long on a human time scale. Plutonium, with a much shorter half-life (17,000 years), is more of a problem. The problem isn't exactly that the fissile fuel gets depleted, as that the process of radioactive decay damages the material. This changes the density and crystalline form of the metal, which can affect how it behaves under the conditions used for ignition. The weapons labs are spending a lot of time, effort, and money to try to figure out how old the metal can be and still function. They aren't allowed to find out the obvious way, by testing, because of the test ban.

Richard E. Barrans Jr., Ph. D.

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