Radioactivity

What is radioactivity?

·       The spontaneous emission of energy from unstable atoms

·       Atoms – Neutrons:Protons (ratio) is not ideal

·       Nucleus approaches a more stable neutron to proton ratio

·       Radioactive decay releases different types of energetic emissions

o   Fission

The three most common types of radioactive emissions

·       Alpha particles

o   Made up of two protons and two neutrons

o   Often referred to as a helium nucleus

o   Positively charged nuclear particle

o   Emitted spontaneously in some types of radioactive decay

o   Produced when Helium atoms are completely ionised

o   

·       Beta particles

o   Form of ionizing radiation

o   Closely related to other types of radiation

o   High-speed electron that has been released from a degenerative radioactive nucleus

o   Low mass and medium-energy

o   One of the least-damaging types of radiation

o   Pose a large health risk – break chemical and create ions, lead to tissue damage

o   Not radioactive

o   

·       Gamma rays

·       Composed of electromagnetic

·       Very penetrating

·       Most useful type of radiation for medical purposes,

o   Also most dangerous because of its ability to penetrate large thicknesses of material

·       Among all electromagnetic waves, gamma rays have

o   Shortest wavelengths

o   Highest frequencies

o   Highest energies 

·       Most energetic form of light

·       Produced by the hottest regions of the universe

Interesting facts about radioactivity

·       Radioactive elements break down (decay) to form lighter atoms

o   Energy released is made up of small, fast-moving particles and high-energy waves(invisible)

o   Elements with naturally occurring radioactive forms

§  Carbon

§  Bismuth

§  Radon

§  Strontium

·       Random process that happens naturally as the isotopes in particular elements decay

·       Isotopes continue to break down over time

·       The length of time that is taken for half of the nuclei in an element to decay is called its 'half-life'(refer to the topic above)

o   Can be very short (milliseconds to hours) or very long (hundreds of thousands of years).

Advantages and Disadvantages of a nuclear plant

Nuclear Plants

Advantages of nuclear plant

·       Bring jobs and prosperity to a town or country

·       Provides the world with most of its electricity 

·       Good for the country’s economy 

·       More efficient than ever before

o    New technology has made them more reliable and safer

§  Evidenced by more and more nations (such as China) building nuclear power plants.

·       Reduce greenhouse gas emissions

·       Although the initial cost of building is high, the running costs are low

·       Reduces dependence on foreign oils and natural gas (like bio fuels).

·       Can be safely stored underground 

·       Release a million times more energy, as compared to hydro or wind energy.

Disadvantages of nuclear plant

·       Radioactive waste

o   Produce a lot of waste material

o   Waste material is extremely hazardous and difficult to dispose off safely

§  Keep on site or is buried underground in huge concrete pits

§  Must be carefully looked after for many thousands of years.

·       High risks associated with accidents

o   Small radiation leaks can cause devastating effects on the surrounding environment and people (Japan)

o   A cataclysmic accident can cause widespread radiation poisoning across many countries

§  Chernobyl Nuclear disaster

·       Terrorist Targets 

o   Because of the wide spread damage a reactor breach could cause

§  Terrorist Targets

§  Some nuclear reactions also produce plutonium in large quantities

·       Used in nuclear weaponry

·       Not renewable

o   Uranium is a scarce metal

o   Will one day run out

§  All nuclear power plants obsolete

·       Time and Money

o   Long time

§  Plan and build a nuclear power plant that is safe and effective

o   Lot of money spent

§  Ensure it is safe

§  Unsafe nuclear plants more prone to accidents

 
 

How is radiation transmitted and why it is harmful

Why is radiation harmful?

·        The delivery of energy waves causes a change in the atoms’ molecular structure

o   If constant exposure happens, the atoms cannot return to normal structure

§  Abnormal atoms become more dominant

§  As the atoms become irregular, the healthy cells that maintains the body’s homeostatic state gets killed due to radiation

·       Hair, nails, bone marrow, mucous membranes

o   Leukemia and other forms of cancer develops

o   People are concern of the deadly effects

·       Normal body tissues vary in their response to radiation

·       Early effects of radiation may be seen a few days or weeks after treatments have started

o   May continue for several weeks after treatments have ended

o   Other effects may not show up until months, or even years, later.

·       Some common side effects

o   Fatigue

o   Skin

o   Mouth and throat

o   Brain

o   Lung

How is radiation transferred?

·       Previously, we learnt about nuclear fusion and nuclear fission, as well as alpha, beta particles and gamma rays…

o   When nuclear fission or fusion occurs, many types of radiation are created

§  Alpha particles, beta particles, gamma rays and neutrons

§  Alpha and beta particles would mostly be harmless

·       Too big to pass through much matter

·       Only pose a serious danger when they're inhaled or fall onto the food we eat

o   Gamma rays and neutrons are much more dangerous following a nuclear explosion

§  Neutrons are heavier than electrons

·       Can easily penetrate matter

·       Gamma rays are photons

o   Have more energy and can easily pass through several inches of a heavy element(lead).