Topic 2: Nuclear Energy

A substance is radioactive if it emits energy in the form of EMR(gamma rays) or particles(alpha, beta, or neutrons)
Nuclear reaction are said to be ionizing because some forms of radiation and particles released can penetrate solid material and damage living cells

Isotopes are elements with the same atomic numbers, but different atomic masses because of a different number of neutrons

*to calculate neutrons mass-atomic#

Isotopes become unstable when the force of repulsion in the nucleus is greater than the nuclear force of attraction holding the nucleus together
The unstable isotope will change into another substance and release energy in the form of radiation and particles

Atomic mass of an element is equal to the nucleons of an element: the number of protons and neutrons in a nucleus

Nuclear Fusion

Nuclear fusion: when 2 smaller nuclei with high-energy join together to form a larger nucleus while releasing energy
Occurs in the sun and all stars
Can we use nuclear fusion to produce energy?
- Not yet! we have plenty of deuterium(raw material for fusion) but we cannot contain the energy produced

Nuclear Fission

Nuclear fission: When a large nucleus splits into smaller nuclei while releasing energy
- Opposite of nuclear fusion
Begins when a large atom such as uranium is struck by a neutron causing it to become unstable
It then splits into 2 smaller nuclei and more neutrons that will go on to hit other atoms, therefor continuing the reaction
- This reaction is difficult to control

CANDU reactor stands for: Canadian Deuterium Uranium Reactor
Uses uranium-235 as fuel
Heavy water(deuterium oxide D2O) is used a moderator(use to sustain fission by slowing down neutrons)
Control Rod absorbs neutrons in an energy shut down(Also help to control the rate of fission)
Steel or concrete is used as shielding
The energy from nuclear fission is used to heat water and produce steam, turning a turbine, spins a generator which creates electricity

Pros and cons

Perspectives to consider	Pro	Con
Societal perspective	Produces large amounts of energy compared to burning coal = efficient	Nuclear materials can be used in nuclear weapons Nuclear material is radioactive
Environmental/ecological perspective	No gaseous emissions	Non-renewable Thermal pollution of air and water Storage of used fuel/radioactive waste Risk of meltdown
Economical perspective	Lower operating costs We have lots of uranium	Nuclear plants cost more money to build

Coal-fired power plant vs Nuclear power plant

	Coal-fired power plant	Nuclear power plant
Fuel source	Coal	Uranium-235
The energy stored in the fuel is called	Chemical potential	Intranuclear potential
Reaction used to release energy from the fuel	Combustion	Nuclear fission(using a neutron)
Energy conversion sequence	Solar→chemical potential→kinetic→electrical	Intranuclear potential→thermal→kinetic→electrical