nulcear power

8/6/2019 Nulcear Power

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Benefits and Nuisances with use of NUCLEAR POWER

The main constituent of nuclear power is nuclear fuel which ismost widely uranium-235.

The reason behind using this uranium is its special ability toundergo a special type of chemical process and that process iscalled Nuclear fission.A brief discussion about Nuclear Fission

Nuclear fission is process of splliting of heavy nucleus likeUranium 235 into small fragments along with emission of largeamount of energy.

Nuclear fission is a nuclear reaction in which the nucleus of anatom splits into smaller parts (lighter nuclei ), often producingfree neutrons and photons (in the form of gamma rays). The twonuclei produced are most often of comparable size, typically witha mass ratio around 3:2 for common fissionable isotopes. Mostfissions are binary fissions, but occasionally (2 to 4 times per1000 events), three positively-charged fragments are produced in

a ternary fission. The smallest of these range in size fromprotons to argon nuclei.


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Fission of heavy elements is an exothermic reaction which canrelease large amounts of energy both as electromagneticradiation and as kinetic energy of the fragments.In order forfission to produce energy, the total binding energy of theresulting elements must be less than that of the startingelement. Fission is a form of nuclear transformation because theresulting fragments are not the same as the original atom.

Fission is usually the product of an energetic nuclear energyinduced by a neutron, although it is occasionally seen as a form ofspontaneous radioactive decay, especially in very high mass-number isotopes. The lack of any exact and predictable

composition in the products (which are produced in a broadprobabilistic and somewhat chaotic manner) distinguishes fissionfrom purely quantum tunnelling processes

Nuclear fission produces energy for nuclear power it is possiblebecause certain substances called nuclear fuels like U-235undergo fission when struck by fission neutrons, and in turn emitneutrons when they break apart. This makes possible a self-

sustaining chain reaction that releases energy at a controlledrate in a nuclear reactor (or at a very rapid uncontrolled rate in anuclear weapon)

The amount of free energy contained in nuclear fuel is millions oftimes the amount of free energy contained in a similar mass ofchemical fuel such as gasoline making nuclear fission a verytempting source of energy. The products of nuclear fission,

however, are on average far more radioactive than the heavyelements which are normally fissioned as fuel, and remain so forsignificant amounts of time, giving rise to a nuclear wasteproblem. Concerns over nuclear waste accumulation and over thedestructive potential of nuclear weapons may counterbalance the


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desirable qualities of fission as an energy source and give rise toongoing political debate over nuclear power.

Now it is obvious we should not everytime initiate the samereaction. but beauty of nuclear fission is that it continues on its


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own and even may become divergent so once started it continueson its own when maintained under controlled conditions. The mainadvantage of using nuclear fission is that is generatestremendous amount of energy. I atom of U-235 produces energywhich will be generated by burning 20000 tones of coals.The actuall energy release in this process is given by

Instantaneously released energy

Kinetic energy of fission fragments . . . . . . . .

168.2 MeV U-233

169.1 MeV U-235

175.8 MeV Pu-239

Kinetic energy of prompt neutrons . . . . . . . . . .

4.9 U-233

4.8 U-2355.9 Pu-239

Energy carried by prompt -rays . . . . . . . . . .

7.7 U-233

7.0 U-235

7.8 Pu-239

Energy from decaying fission products

Energy of -particles . . . . . . . . . . . . .


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5.2 U-233

6.5 U-235

5.3 Pu-239

Energy of anti-neutrinos . . . . . . . . . . . . . .

6.9 U-233

8.8 U-235

7.1 Pu-239

Internal structure of Nuclear reactor


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History of chain reaction and nuclear fission

A nuclear chain reaction was proposed by Leo Szilard in 1933,shortly after the neutron was discovered, but some years beforenuclear fission was discovered. Szilard proposed to use neutronsfrom certain nuclear reactions in lighter isotopes, to inducefurther reactions in light isotopes that produced more neutrons.He did not envision nuclear fission as one of these reactions,since this reaction was not known at the time. Experiments heproposed using beryllium and indium failed.

Later, after nuclear fission was discovered in 1938, Szilardimmediately realized the possibility of using neutron-inducedfission as the particular nuclear reaction needed for a chain-reaction, so long as fission also produced neutrons. In 1939, withEnrico Fermi, Szilard proved this neutron-multiplying rection inuranium. In this reaction, a neutron plus a fissionable atom causesa fission resulting in a larger number of neutrons than the single

one that was consumed in the initial reaction. Thus was born thepractical nuclear chain reaction by the mechanism of neutron-induced nuclear fission.

Specifically, if one or more of the produced neutrons themselvesinteract with other fissionable nuclei, and these also undergofission, then there is a possibility that the macroscopic overallfission reaction will not stop, but continue throughout the

reaction material. This is then a self-propagating and thus self-sustaining chain reaction. This is the principle for nuclearreactors and atomic bombs.

[The above description is somewhat simplified. The crucial issueis whether enough of those secondary neutrons themselves


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produce a further fission. The nuclear chain reaction is describedin significantly more detail in the article on Stan Ulam, who"discovered" or realized the details of the amplification concept,when fission by prompt fission neutrons were the mechanism].

Demonstration of a self-sustaining nuclear chain reaction wasaccomplished by Enrico Fermi and others, in the successfuloperation of Chicago Pile-1, the first artificial nuclear reactor, inlate 1942.then people freely started using this ultimate source ofenergy regularly and many nuclear power plants were set up. Andpeople started looking for better advancements in sametechnology and this process is still going.

As our main discussion is on advantages and disadvantages ofnuclear power

So lets first discuss the advantagesof nuclear power!!!

Among the many benefits of nuclear power, the mainadvantage this type of power has over other methods isthat it is a clean way to produce energy as it does not resultin the emission of any of the poisonous gases like carbondioxide, sulfur dioxide or nitrogen dioxide. In todays worldwhen pollution of the atmosphere is one of our main worries,an option such as this is definitely preferable compared to

burning of fossil fuels which causes so much ofpollutionWhen compared to the fossil fuel waste, thenuclear waste which occurs due to the production of nuclearpower is not only small in quantity but also remains confinedso as not to affect anyone in its surroundings. It has beenproved that if a typical family of four uses nuclear power


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for all its needs then the waste produced over a period of alifetime would be as small as a golf ball.

The disposal of nuclear waste which results during the

generation of nuclear power is much easier because it is justdumped in to a geological site where it decays over a periodof time and has no negative impact on the ecosystem. Thisturns out to be one of the main benefits of nuclear power ascompared to the chemical waste like arsenic or mercurywhich refuse to decompose or poisonous gases which causeglobal warming, acid rain and smog.

Nuclear power is safe and even though there have been two

serious accidents in Pennsylvania and Chernobyl, these arebut sporadic incidents when compared to the rate ofaccidents which occur in fossil fuel industries, coal minesand gas pipelines which have a history of eruption.

One of the main benefits of nuclear power is that it is anextremely reliable source of power because most nuclearreactors have a life cycle of 40 years which can be easilyextended further for 20 more years.

The availability of nuclear power is competitive compared toother sources of power like oil and gas since the cost of thenuclear fuel is a small part of the total reaction andtherefore even if there is a slight fluctuation in the marketthe entire reaction need not be affected.

The source of nuclear power is uranium and this is availablein abundance in the crust of the Earth with major deposits

being uncovered in Canada and Australia. Therefore sincethe source of nuclear power is readily available now and alsofor centuries to come, this form of power is virtuallyinexhaustible.


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The nuclear power is generated at a place which is known asthe nuclear power station and this is a compact buildingwhich is as big as the area occupied by a football stadium.

The biggest fear associated with nuclear power is the fearof radiation and this can only be overcome by educating thepeople about the method of radiation and its behavior.People would be surprised to know that radiation has been apart of our environment ever since its existence and thatradiation in moderate amounts can even be advantageous toour health. Therefore, radiation need not be feared frombut can be channeled appropriately to serve mankind in a

positive way. The main benefits of nuclear power are that it is good,

scientific as well as environment friendly because of whichit is being supported by many ecological organizations andenvironmentalists who were previously biased against it.

These are some main advantages of nuclear energy but it also hassome major disadvantageswhich make its use risky so few ofthem are.

Waste

One of the biggest disadvantages of nuclear energy is thewaste. Although the output of waste is relatively small, it


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releases harmful radiation as it decays. There is no methodto get rid of the radioactivity of the waste or speed up therate of decay. The waste must be sealed and buried in asafe location to prevent contamination of the environmentand other people. Currently, there are no suitable locationsthat provide a permanent storage site for nuclear waste.

Accidents

Another one of the biggest disadvantages of nuclear energyis the occurrence of accidents due to core meltdown. These

accidents happen when the core overheats and radiationproducts are allowed to escape the building. Thiscontaminates the surrounding area with radioactive materialthat is very harmful people's health, often causing cancer.

Cost

Cost is also one of the major disadvantages of nuclearenergy. It costs between three and five billion dollars justto build a nuclear power plant. Maintenance and operatingcosts are also high because lots of money must be sent onsafety systems in case something goes wrong.

Weapons

One of the most feared disadvantages of nuclear energy is

the potential for weapons. Each year, every nuclear reactoris capable of making enough plutonium to build over thirtynuclear bombs. Nuclear plants must be secured well enoughto prevent this material from falling into the wrong hands.


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Nuclear power cannot solve global warming:

Once seen as the solution to global climate change, nuclear poweris far from it. Everywhere along the nuclear chain - from the

mining of uranium to its transportation to the construction of thepower plant - greenhouse gases are emitted.

Furthermore, their construction takes too long to solve globalwarming. In fact, investing in nuclear power deprives otherefforts - such as energy efficiency, conservation and renewableenergy - of further funding and development.Chernobyl, in TheUkraine and affecting Russia and Belarus too was another story

and still today serves to highlight safety as a disadvantage ofnuclear energy. With Chernobyl, there was a full scale breakdown,which was not contained. A massive release of nuclear radiationoccurred and the complete affect of this accidental release willnot be known for generations. Although the authorities movedquickly to contain and remediate the problem (unlike the slowgovernmental reaction in the Gulf of Mexico with the BPDeepwater Horizon offshore oil rig disaster), there is only so

much you can do to contain nuclear radiation. The radiationbecame distributed within the environment for over a hundredmiles and will remain in the environment for a very long time.

The major disadvantage of nuclear power is safety.Proponents would argue that despite the three notoriousnuclear accidents, nuclear energy still has a very good trackrecord. Whether that may actually be correct, like airplanes

versus cars, the magnitude of a problem when it occurshowever infrequently compounds the public perception ofrisk. For example, it is known that airplanes have a bettersafety record than automobiles, but when there is a planecrash it is a disaster and grabs headlines. Car crashes areso common that they are not even news. Similarly, any


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problem with nuclear power is a big issue and garners majormedia coverage.

Nuclear Proliferation: Proliferation is the spread of nuclearweapons to unreliable owners a disadvantage of nuclearpower. Increasingly proliferation is becoming the primedisadvantage. This is because it is an unfortunate reality ofthe world that a lot of governments cannot be consideredreliable or trustworthy with dangerous substances, andincreasingly it is feasible for them to develop nuclearweapons. In a world where freedoms and equality have beenattacked, it becomes of concern that such governments

might possess nuclear weaponry, or that non-governmentalorganizations like terrorist groups might use nuclear bombsto serve some twisted political agenda.

In the cold war period, nuclear weapons were only accessibleto generally predictable powers, whether the United Statesor Soviet Union, or the U.K. or reportedly Israel. However,with the fragmentation and realignment following the end ofthe cold war increasingly weapon technology has found its

way to less predictable powers. Such unstable or territorially ambitious governments could

secretly transfer crude nuclear weapons to non-governmental organizations, such as terrorist groups theycontrol or influence. For example it is well within theimagination that the government of Iran, or a rogueoperatives within the government of Pakistan would handover a nuclear weapon to a terrorist group they control or

influence, such as Hezbollah or Hamas in the case of Iran orthe Taliban in the case of Pakistan. Similar concerns arepresent with North Korea weapons control.

As the debate concerning Irans drive to create a nuclearpower industry goes on, it is evident that their true goal isnot just to produce electricity. After all when sitting on a


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field of oil, there is no need for nuclear electric generation.So the reality is Iran, with its unstable regime subject to asimmering discontented population is the epitome of anunstable and untrustworthy owner of a nuclear weapon.However it is not only Iran, but other emergingdictatorships that seek a nuclear weapon as well.

Nuclear reactors can be used to help generate weaponsgrade bomb materials so nuclear weapon proliferation is ofgreat concern as a disadvantage of nuclear power.

Nuclear Waste Disposal: Another disadvantage of nuclearenergy is disposal of the spent fuel rods. They remain

radioactive literally for hundreds if not thousands of years.So they must be disposed of in a secure nuclear wastedisposal facility. Naturally nobody wants a nuclear wastedump in their backyard, so location of a suitable long-termstorage has bedeviled the industry for years.

Discussions of the disadvantages of nuclear power naturallyfocus on the disastrous enormity if the consequence of anuclear disaster - whether involving safety or proliferation.

Nuclear Energy Safety: Safety is the primary disadvantageof nuclear power as viewed by the consuming public. BeforeChernobyl and Three Mile Island, nuclear energy was viewedas a great green, non-polluting source of electrical powerproduction. Then came along those two famed nuclearaccidents, and that changed the discourse for many years.By comparison Three Mile Island was mild a relativelysmall amount of nuclear radiation released, and quickly

contained before any serious releases, or other damage tothe reactor core could occur. However, as the debatestarted to favor nuclear power development came the Japanearthquake of 2011 and the nuclear disasters at theFukushima Daiichi (Dai-Ichi) nuclear power stations ofTokyo Electric Power Company in Okumamachi, Fukushima


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prefecture - the initial disaster at Fukushima I andcontainment issues and subsequent disasters at Fukushima2, 3 and 4 - four of the six reactors in the Fukushima Dai-Ichi complex. All nuclear plants are vulnerable to accidentsor attacks. Nevertheless, if an accident did occur, thecurrent evacuation plans are completely unrealistic. Inaddition, the Price-Anderson Act ensures the utility'sliability of an accident is limited to only $10.8 billion. This isabsurd, considering a serious reactor accident could causeas much as $600 billion of damage. Once again, the balancewould likely have to be paid by us, the taxpayers.

There are better alternatives:

What bothers us most is we already have better, cleaner, saferand cheaper alternatives available and ready to implement.Perhaps with the recent election of our new US government,nuclear energy will be put to rest and renewable energy will be

harnessed on a larger scale.

But while we wait, it is possible to start harnessing renewableenergy at home. What's more is, it does not cost very much andis rather simple to implement. Various solar and wind powerguides have already become available, which you can see in ourreviews section.


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So this discussion ends with a conclusion that nuclear

power is ultimate source of energy but it still needs

some developments in its technique so that its use will

become more safe and we will not experience energy

crisis!!!!

Pranav NaikSY E&TC

110907087

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