What is fusion power?
A: Fusion power is a proposed form of power generation that would generate
electricity by using heat from nuclear fusion reactions.
In a fusion process, two lighter atomic nuclei combine
to form what?
A: A heavier nucleus, while releasing energy.
Devices designed to harness this energy are known as
what?
A: Fusion reactors.
Fusion processes require fuel and a confined
environment with sufficient temperature, pressure, and confinement time to
create a what?
A: A plasma in which fusion can occur.
The combination of these figures that results in a
power-producing system is known as what?
A: The Lawson criterion.
In stars, the most common fuel is what?
A: Hydrogen.
Gravity provides extremely long what?
A: Confinement times.
Proposed fusion reactors generally use heavy hydrogen
isotopes such as what?
A: Deuterium and tritium.
Most designs aim to heat their fuel to how hot?
A: 100 million degrees.
As a source of power, nuclear fusion is expected to
have many advantages over what?
A: Fission.
These include reduced radioactivity in operation and
little what?
A: High-level nuclear waste, ample fuel supplies, and increased safety.
The needed combination of temperature, pressure, and
duration has proven to be difficult to what?
A: Produce in a practical and economical manner.
Research into fusion reactors began in the
1940s, but
to date, no design has produced what?
A: More fusion power output than the electrical power input.
A second issue that affects common reactions is
managing neutrons that are released during the reaction, which over time do
what?
A: Degrade many common materials used within the reaction chamber.
Fusion researchers have investigated various what?
A: Confinement concepts.
The early emphasis was on what three main systems?
A: z-pinch, stellarator, and magnetic mirror.
What are the current leading designs?
A: They are the tokamak and inertial confinement (ICF) by
laser.
Researchers are also studying other designs that may
offer what?
A: Cheaper approaches.
Fusion reactions occur when two or more atomic nuclei
come close enough for long enough that the nuclear force pulling them
together exceeds what?
A: The electrostatic force pushing them apart, fusing them into heavier
nuclei.
Since hydrogen has a single proton in its nucleus, it
requires the least what?
A: Effort to attain fusion, and yields the most net energy output.
Since it has one electron, hydrogen is the easiest fuel
to what?
A: Fully ionize.
The strong force acts only over what?
A: Short distances (at most one femtometre, the diameter of one proton or
neutron),
The amount of kinetic energy needed to bring the fuel
atoms close enough is known as what?
A: The "Coulomb barrier".
Ways of providing this energy include speeding up atoms
in a particle accelerator, or what?
A: Heating them to high temperatures.
Once an atom is heated above its ionization energy, its
electrons are what?
A: Stripped away, leaving just the bare nucleus.
This process is known as what?
A: Ionization.
The resulting nucleus is known as a what?
A: An ion.
The result is a hot cloud of ions and free electrons
formerly attached to them known as what?
A: Plasma.
Because the charges are separated, plasmas are what?
A: Electrically conductive and magnetically controllable.
Many fusion devices take advantage of this to confine
the particles as they are what?
A: Heated.