Conservation, conversion and efficiency II

Nuclear Fission

Splitting of a very heavy atomic nucleus into two lighter nuclei, releasing an extremely large amount of energy that must be controlled to harness it.

Daughter Products (Fission)

Highly radioactive byproducts of nuclear fission.

Nuclear Fusion

Fusing together of two light nuclei to form a heavier one, releasing a large amount of energy.

Daughter Product (Fusion)

Helium-4; not harmful, considered a beneficial byproduct.

Lanthanides and Actinides

Elements that can be used to power a nuclear reactor, shown on the chart of nuclides.

Nucleus

Composed of protons and neutrons (nucleons), held together by the strong nuclear force.

Coulomb's Law

Describes the repulsive force between protons within a nucleus.

Atomic Number (Z)

The number of protons in an atom.

Atomic Mass (A)

The total number of protons and neutrons in an atom.

Isotopes

Atoms with the same atomic number but different atomic mass due to varying numbers of neutrons.

Strong Nuclear Force

A fundamental force that holds protons and neutrons together in the nucleus.

Binding Energy

The energy required to separate the nucleus into individual protons and neutrons.

Nuclear Reactor

A system that controls nuclear fission to generate power, composed of four main parts: fuel, moderator, control systems, and coolant.

Control Rods

Absorb excess neutrons to regulate the fission chain reaction; commonly made of graphite.

Moderator

Slows down neutrons to thermal speeds, improving efficiency of the nuclear reaction.

Nuclear Fuel

Best isotopes are uranium-235 and plutonium-239; uranium must be enriched for use in reactors.

Uranium Enrichment

Process of increasing the proportion of uranium-235 from natural uranium-238 to make it usable in reactors.

Plutonium Production

Does not exist naturally; must be produced in nuclear reactors and reprocessed for fuel use.

Closed Fuel Cycle

A process where plutonium is bred and extracted for reuse in another reactor.

Chain Reaction

A self-sustaining process where fission releases neutrons that trigger more fission events.

Runaway Chain Reaction

An uncontrolled reaction that can lead to reactor accidents if control rods fail.

Thermal Neutrons

Neutrons that have been slowed by a moderator to increase the probability of fission.

Uranium-236

A highly radioactive isotope that undergoes fission spontaneously.

Ionizing Radiation

Radiation that damages living cells by breaking molecular bonds, leading to DNA damage.

Radiation Dose

High exposure (~5 Sv) is lethal; prolonged low-dose exposure can cause mutations and cancer.

Background Radiation

Naturally occurring radiation from cosmic rays and the Earth's crust; average exposure in the UK is 2 mSv per year.

Nuclear Safety

Concerns over reactor accidents and radioactive material release; e.g., the Chernobyl disaster (1986).

Radioactive Waste

Spent nuclear fuel remains hazardous for thousands of years, leading to disposal concerns.

Deep Geological Disposal

Proposed method of storing nuclear waste underground, but long-term security is uncertain.

Nuclear Renaissance

UK plans to build two new advanced light-water reactors with 1.6 GW capacity each, costing £22 billion.

Pros of New Nuclear Reactors

Increased safety, better economic competitiveness, and longer plant lifetimes (60 years).

Nuclear Power and CO₂

Nuclear power does not contribute to CO₂ emissions or acid rain.

Energy Security

Nuclear power does not suffer from supply concerns like fossil fuels.

Nuclear Power in the UK

Provided ~18% of the UK’s electricity but is costly to generate

UK Nuclear Plant Lifetimes

Most UK nuclear power stations will reach the end of their operating lives by 2025.