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Glossary

A

Alpha Decay (α)

Criticality: 3

A type of radioactive decay where an atomic nucleus emits an alpha particle, causing its atomic number to decrease by 2 and its mass number by 4.

Example:

Uranium-238 undergoes Alpha Decay (α) to transform into Thorium-234, releasing a helium nucleus.

H

Half-life

Criticality: 3

The specific time period required for half of the radioactive atoms in a given sample to undergo radioactive decay.

Example:

If a sample of a substance has a half-life of 10 days, after 20 days, only one-quarter of the original radioactive material will remain.

N

Nuclear fission

Criticality: 2

A nuclear reaction where a heavy atomic nucleus splits into two or more lighter nuclei, typically releasing a significant amount of energy.

Example:

The energy generated in nuclear power plants is a result of controlled nuclear fission of uranium atoms.

Nuclear fusion

Criticality: 2

A nuclear reaction in which two or more light atomic nuclei combine to form a heavier nucleus, releasing a tremendous amount of energy.

Example:

The immense energy output of the Sun is powered by nuclear fusion, where hydrogen nuclei combine to form helium.

R

Radioactive decay

Criticality: 3

The spontaneous process by which an unstable atomic nucleus transforms into a more stable one by emitting particles and/or energy.

Example:

Carbon-14 undergoes radioactive decay to become Nitrogen-14, a process used for carbon dating ancient artifacts.

a

alpha particle

Criticality: 3

A particle consisting of two protons and two neutrons, identical to a helium-4 nucleus, emitted during alpha decay.

Example:

When a heavy nucleus undergoes alpha decay, it ejects an alpha particle, reducing its mass and atomic number.

c

charge

Criticality: 3

A fundamental property of matter that dictates its interaction with electromagnetic fields; in nuclear reactions, the total *charge* of the system must remain constant.

Example:

During beta decay, a neutron transforms into a proton and an electron, ensuring that the total charge before and after the decay remains balanced.

d

daughter

Criticality: 2

The new nuclide that is formed as a result of the radioactive decay of a parent nucleus.

Example:

When Carbon-14 decays, Nitrogen-14 is the stable daughter nuclide produced.

n

nucleon number

Criticality: 3

The total count of protons and neutrons within an atomic nucleus, which must be conserved in all nuclear reactions.

Example:

When Uranium-238 undergoes alpha decay, its nucleon number decreases by 4, reflecting the emission of an alpha particle.

p

parent

Criticality: 2

The original, unstable nuclide that undergoes radioactive decay to form a new, often more stable, nuclide.

Example:

In the decay chain of Uranium-238, Uranium-238 is the parent nuclide that eventually decays into Lead-206.

r

radioactive

Criticality: 3

Describes isotopes with unstable nuclei that spontaneously decay, emitting particles and/or energy to achieve a more stable state.

Example:

Iodine-131 is a radioactive isotope used in medical imaging due to its predictable decay properties.