Overview of Nuclear Reactions and Radiation Effects

Nuclide

A specific isotope of an element.

Nuclei

Plural of nucleus.

Unstable nuclide

An isotope that will spontaneously undergo a nuclear reaction.

Stable nuclide

An isotope that never undergoes spontaneous reactions.

Nucleon

A proton or a neutron.

Parent nuclide

A nuclide that decays into smaller, daughter nuclides.

Transmutation

The changing of an element into another by nuclear decay, nuclear bombardment, or some other nuclear reaction.

Nuclear isomerization

A nucleon in an excited state relaxes emitting a photon of gamma radiation.

Nuclear decay (radioactive decay)

The spontaneous emission of particles and/or energy as an unstable nuclide transforms into another nuclide.

Alpha decay

The spontaneous emission of a helium nucleus from an unstable nuclide.

Beta decay

The spontaneous emission of an electron from the nucleus of an unstable atom as a neutron becomes a proton.

Gamma rays

Frequently released during nuclear isomerization as products of a nuclear reaction relax.

Positron Emission

The emission of a positive electron, positron, from an unstable nuclide as a proton becomes a neutron.

Electron capture (κ-capture)

When an electron is sucked into the nucleus of an atom, converting a proton to a neutron.

Nuclear Fission

When a large nuclide spontaneously breaks into smaller daughter nuclides.

Alpha particle

Symbolized as (_2^4)He or α, representing a helium nucleus.

Beta particle

Sometimes written as (_−1^0)e or β-.

Positron

Represented by (_+1^0)β, emitted along with an electron neutrino.

Electron neutrino

A nearly massless neutral subatomic particle emitted during positron emission.

Nuclear Chain Reaction

A process where a product of a reaction is also a reactant, often occurring when a lot of U-235 is present.

Nuclear Fusion

A reaction where two smaller nuclei combine to form a larger nuclide, producing a lot of energy, such as the energy produced by the sun.

Artificial Nuclear Reactions

Nuclear reactions caused by human-made experiments, often involving high-speed collisions of particles to create new elements.

Nuclear Reactions

Reactions that change the nuclei of the atoms involved, which can involve the creation or destruction of matter as energy is consumed or produced.

Ionizing Radiation

Radiation that has enough energy to remove tightly bound electrons from atoms, potentially causing harm.

Particle Radiation

A type of ionizing radiation that includes alpha (α), beta minus (β-), and beta plus (β+) particles, which can produce unstable molecules or radicals.

Radical Cascade

A chain reaction where a radical produces another radical, continuing until energy is dissipated or a stabilizing chemical is encountered.

Electromagnetic Radiation

Radiation that can ionize substances depending on their threshold frequencies, which are typically in the higher energy side of ultraviolet radiation.

Somatic Mutations

Mutations that occur in any cell of the body except gametes, potentially causing cell death or cancer without affecting offspring.

Germ-line Mutations

Mutations that occur in gametes, which can lead to mutant offspring and may cause miscarriages.

Penetrating Power

The ability of radiation to pass through materials, which can be mitigated by shielding.

Nuclear Isomerization

A change in the nuclear structure that does not alter the nuclides involved.

Transuranium Elements

Elements with atomic numbers greater than 92 that have been artificially produced and are typically unstable and radioactive.

Radiation Exposure Duration

The length of time one is exposed to ionizing radiation, where longer exposure increases the risk of adverse effects.

High-Speed Collisions

Collisions of particles at high speeds that can lead to the production of new elements in artificial nuclear reactions.

Radiation Shielding

The different kinds of radiation are prevented from penetrating tissue by increasing levels of shielding.

Ionizing Radiation Measurement

The measurement of ionizing radiation utilizes the ionizing nature of radiation to make it visible to us or a machine.

Imaging

Uses chemistry based in ionization of modern digital imaging to detect high energy photons to see radioactive substances.

Geiger Counter

An instrument that uses the ionization of gas in a tube to measure how much radiation a source is giving off.

Scintillation Counters

Machines that measure the amount of a radioactive substance in a sample prepared with a scintillating material that flashes whenever an ion is produced.

Dosimeter

A film badge that measures the cumulative amount of radiation you are exposed to.

First Order Kinetics

Radioactive decay is an example of first order kinetics, meaning the amount of nuclides that decay is directly proportional to the amount of the decaying nuclides.

Half-Life

The amount of time it takes for half the sample to decay, which is a constant that depends on the nuclide.

Carbon-14 (C-14)

An unstable isotope of carbon formed in the atmosphere by the disintegration of atoms producing free neutrons that react with nitrogen-14.

Beta Decay

The process by which C-14 breaks down, represented by the equation (_6^14)C → (_7^14)N + (_−1^0)β.

C-14 Half-Life

The half-life of C-14 is about 5,730 years.

C-14 Dating

Can reliably date organic material to ~50,000 years; older than that there isn't enough C-14 left to get a reliable date.

C-14:C-12 Ratio

Living plants and animals have a constant C-14:C-12 ratio as long as they are alive and able to take in more C-14.

C-14 Ratio Decrease

At death, no more C-14 enters into their tissue and the C-14:C-12 ratio decreases.

Fission nuclear reactors

A major source of carbon emission-free energy where heat is produced by a nuclear chain reaction.

Critical mass

The minimum amount of fissionable material needed to maintain a nuclear chain reaction, approximately 52 kg of uranium.

Control rods

Materials inserted into a nuclear reactor to absorb excess neutrons and maintain a critical state.

Subcritical reactor

A state where the reactor has insufficient material to sustain a fission reaction.

Critical reactor

A controlled state of a reactor where the fission reaction is maintained at a steady rate.

Supercritical reactor

A state of a reactor that can lead to an uncontrolled reaction and potential disaster.

Chernobyl accident

A 1986 nuclear disaster in Ukraine caused by a test failure, leading to immediate deaths and long-term health effects.

Low Level Waste

Radioactive waste such as tools and clothing that is usually short-term and less hazardous.

Intermediate Level Waste

More radioactive waste that requires storage in shielded areas for a prolonged time.

High Level Waste

Highly radioactive waste that needs extensive shielding and cooling, requiring long-term secure storage.

Nuclear accidents

Incidents in nuclear plants that can lead to the spread of radioactive material and contamination.

Evacuated radius

A designated area around a nuclear accident site, such as the 20km radius around Fukushima.

Radioactive waste recycling

The process where about 96% of nuclear waste is recycled, leaving 4% as high-level waste needing secure storage.

Long-term effects of nuclear accidents

Health and environmental impacts that are studied over time following nuclear incidents.

Nuclear reactor cooling

The process of maintaining safe temperatures in reactors, which can involve pumping seawater in emergencies.

Contamination of the ocean

The spread of radioactive materials into marine environments due to nuclear accidents.

Nuclear preparedness

Plans and resources in place to respond to nuclear emergencies, such as those provided by United Way of Connecticut.