How do radioactive isotopes decay, and what types of radiation are produced? How dangerous is this radiation?
Why You Should Care
Radioactive decay is a natural process where isotopes release energy and particles. The more neutrons the atom has, the more unstable it will be. The more unstable the isotope, the more energy and particles will be released as radiation. Radiation is classified by the amount of matter and energy released (alpha releases the most matter and has the least energy, beta has less matter and more energy, and gamma has the least matter and the most energy). Gamma radiation is most dangerous with proximity, as it can instantly damage cells and cause DNA damage. Alpha radiation is most dangerous if it is inhaled or ingested, as its radiation damages cells over the long term.
This radiation is what powers reactors. Each step also creates large amounts of low-level radioactivity that will take millions to billions of years to become safe.
Test Your Vocabulary
Choose the correct term for each of the following definitions:
Term
Definition
Atoms that spontaneously emit subatomic particles and/or energy.
The time it takes for half of the radioactive isotopes in a sample to decay to a new form.
Hollow metal cylinders filled with uranium fuel pellets for use in fission reactors.
Rods that absorb neutrons and slow the fission chain reaction.
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1.
How long would it take for half of radioactive polonium-210 to decay?
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According to the table, which unstable isotope has the longest half-life?
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Polonium-214 has a half-life of 1.5 milliseconds. How long would it take for there to be 12.5% of the original polonium-214 left?
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4.
If radioactive elements naturally decay, why are they considered long-term risks to the environment?
Radioactivity releases energy and particles as elements decay. Half-lives measure how long it takes, not how much is released, so half-lives that last hundreds, thousands, or millions of years mean that the risks also last that long.
Infographic 27.6: Radioactive Isotopes Can Release One or More of Three Different Kinds of Radiation
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Which of the forms of radiation from decay has the MOST penetrating power?
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Which form of radiation is MOST likely to enter the body through eating or by being breathed in?
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Lead shielding is often used around reactors to block which radiation(s)?
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8.
After the Chernobyl disaster in 1986, which radiation showed up in cows and ultimately in milk?
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9.
If the goal of nuclear power generation is creating radiation that has the most energy and smallest release of matter, then which type of radiation would be the best?
Alpha radiation releases the least energy and most matter, so we would want to minimize this radiation. Gamma radiation has the most energy and releases the least matter, so it is the goal of nuclear power generation.