Francis Tenazas Nuclear Power Point Copy

8/6/2019 Francis Tenazas Nuclear Power Point Copy

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Chernobyl Disaster

y On April 26, 1986, anuclear power plantlocated at Chernobyl,Russia had a catastrophicmeltdown killing anestimate of 28 people afew weeks after the

incident. It contaminatedneighboring towns such asBelarus, risking itsresidents of cancer andother dire diseases.


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In Context with our Community

We Do Not Want This!

Let me explain to you further

how Nuclear Power works,and what its Consequences

are.


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Nuclear power plants and Nuclear weapons run

and initiate with the use ofNuclear Fission

y A nuclear fission is a nuclear reaction in which the nucleus ofan atom splits into two or more pieces.

y This is triggered when an atomic nucleus absorbs a neutronmaking it unstable(fissile), and subsequently undergo fission.


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Here is a breakdown of what happens in a

nuclear fission, with the use of a word equation.

y When a fissile material such as Uranium-235 absorb a

neutron, it produces a highly unstable Uranium-236.This in hand causes it to break off, splitting into two ormore atoms (Krypton-91, Barium-142), and a fewneutrons.

yThis process, observes the law of conservation of mass.If you add up the total of mass of the product, it willequate with the mass of reactant.

y Nuclear Fission also discharges radioactive particles, a

main factor why I protest nuclear activity in our area.


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Damaging Effects of Radioactivity

y Exposure to radioactivity can damage the geneticblueprint of the living cells. This can either kill your

cells, or sometimes cause it to multiply and become acancer.

y This can alter your DNA sequence, and consequently

cause mutation.


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Another Problem with Nuclear

Energy- Is its radioactive waste products.

The use and production of radioactive materials

generate radioactive waste which can be veryharmful to our community

The fact that the only way to dispose of suchhazardous material is through its nature of decay,involving multiple half lives that can range to amillion years make it detrimental to productionand to our environment.


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Half LifeyA half life of a radioisotope is

the time it takes for half of the

nuclei to decay spontaneously.y This is the decay series of

uranium-238. It involvesmultiple decays before it

becomes the stable lead-206which is now suitable fordisposal.


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Chain Reactiony When an atom undergoes nuclear fission, a few neutrons

are ejected from the reaction.

y A chain reaction can occur from this.

y The neutrons released from thereaction can initiate other

atoms to undergo fissionand continue.

y This is used for nuclear reactors andweapons because it is able to

incur high levels of energy.

Different levels of energy can be obtained by the mannerthe chain reaction is played. These are labelled as theSubcritical, Critical, and Supercritical mass. The critical

mass is what we should focus.


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Critical mass is observed to achieve a

sustained chain reaction.y In order to utilize the energy from a chain reaction, the

right purity and size must be used.

y The chain reaction is somewhat balanced because not all

emitted neutrons are absorbed.y Nuclear reactors comply with this enabling them to

harness the high energy of its nature with a sense ofsustainability.

y Despite the management, risks are still present


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Nuclear Fuel

y There are different possible fuels that can be used toderive nuclear energy. A few examples are uranium-235and plutonium-239. They are both readily fissile.

y But the most commonly used fuel is uranium-235because it is found in the earths crust.

y However, uranium-235 is very scarce. A chain reactioncan not occur with such insufficient composition, thus

it must be enriched.y Nuclear weapons require over 90% purity, while

reactors only need about 3%. Despite the lowpercentage for reactors the risks are on its mechanism.


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The Nuclear ReactoryA nuclear reactor is composed of: fuel rods, moderator,

control rods, coolant and is enclosed with a radiationshield.


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Fuel Rods

y Fuel rods are thin aluminum tubes filledwith enriched uranium, or such

as, in pellet form. By

enriched, I mean increasingthe purity of uranium-235 to over3%. This is done by reducing the

amount of uranium-238 in thecomposition, thus making it able

to undergo a sustained chainreaction, harnessing the right amount of energy.Fuel rods eventually get depleted. Each needs to bereplaced every four years or so.


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Moderator Control Rods

y For a nuclear fission to occur,a thermal neutron is ideal.This is where the moderatoris in use. It slows down ormoderates the speed of the

free neutron making it easierfor an isotope to absorb aneutron.

y Some materials that arecommonly used as

moderators are: Water, heavywater, carbon dioxide, andgraphite.

y A nuclear chain reaction cancreate a great amount ofenergy. The number ofneutrons released during theuncontrolled fission chain

reaction grows exponentially,releasing enormous amountsof energy in a split second.This can be controlled withthe help of control rods.

When the control rods arelowered the number ofneutrons are managed, thus itis sustained.


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How it Works

y The core consistsof the fuel rods

and control rodsimmersed in

water which is themoderator. When

the chain reactionis started an enormous

amount of heat energy is produced, thus goes to theturbines and produce energy. The heated water is thenpassed through a coolant which brings the water backto the core. Multiple coolant pipes are installed in actto prevent meltdowns which can cause a catastrophic

accident.


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Another way of getting rid of radioactive

waste is by not having it at all!

y Consider the risks

y Consider the safety of our Community

yJoin me work for a nuclear free world

Francis Tenazas Nuclear Power Point Copy

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