Chapter 5 RADIOACTIVITY5.4 NUCLEAR ENERGYA student is able todefne atomic mass unit (a.m.u.)describe nuclear fssioni!e e"amples o# nuclear fssiondescribe chain reactionsdescribe nuclear #usioni!e e"amples o# nuclear #usionrelate the release o# ener$ in a nuclear reaction %ith a chane o# mass accordin to the e&uation describe the eneration o# electricit$ #rom nuclear fssion5.4 NUCLEAR ENERGY2mc E =A student is able to'usti#$ the use o# nuclear fssion in the eneration o# electricit$sol!e problems in!ol!in nuclear ener$5.4 NUCLEAR ENERGYAtomic mass unit (a.m.u.)(uclear ener$ is the ener$ released durin the splittin and #usin o# atomic nuclei.The stud$ o# nuclear reactions in!ol!es the mass o# the nucleus.)ince the mass o# the nucleus is !er$ small* another unit #or mass is introduced so that !alues o# nuclear mass can be %ritten in a more con!enient #orm.5.4 NUCLEAR ENERGYAtomic mass unit1 atomic mass unit or 1 u is 1/12 of the mass of the carbon-12 atom.The mass o# one carbon+,- atom is ,...-/5 " ,0+-/ 1* there#ore5.4 NUCLEAR ENERGYkg 10 66 . 1 u 1kg 10 99265 . 1121u 12726 = =Atomic mass unit5.4 NUCLEAR ENERGYNuclear FissionNucear !ssion is the splitting of a heavy nucleus into t%o lihter nuclei.5.4 NUCLEAR ENERGYn n1090381435410235923 Sr Xe U + + = +Nuclear FissionNucear !ssion usuall$ occurs %hen the nucleus o# an atom is bombarded %ith a neutron.5.4 NUCLEAR ENERGYn n1090381435410235923 Sr Xe U + + = +Nuclear FissionThe ener$ o# the neutron causes the taret nucleus to split into t%o (or more) nuclei that are lihter than the parent nucleus* reeasin" a ar"e amount of ener"# durin the process.5.4 NUCLEAR ENERGYn n1090381435410235923 Sr Xe U + + = +Nuclear Fission2iure sho%s a slo% neutron hittin a uranium+-35 nucleus* causin it to split producin strontium+.0* "enon+,43 and three neutrons. The e&uation #or the reaction can be %ritten as55.4 NUCLEAR ENERGYn n1090381435410235923 Sr Xe U + + = +Chain ReactionA nuclear fssion reaction produced three #ree neutrons.5.4 NUCLEAR ENERGYChain ReactionIn one o# these neutrons bombards another uranium+-35 nucleus then more fssion %ill occur* releasin more neutrons. In this %a$* a chain reaction is produced.5.4 NUCLEAR ENERGYChain ReactionA chain reaction is a sel# 6 sustainin reaction in %hich the products o# a reaction can initiate another similar reaction b$ a neutron.5.4 NUCLEAR ENERGYChain ReactionIn nuclear reactions* a controlled chain reaction is used to enerate electrical ener$.5.4 NUCLEAR ENERGYChain ReactionI# uncontrolled chain reaction ta1es place the hue amount o# ener$ bein released and resultin in an e"plosion such as an atomic bomb.5.4 NUCLEAR ENERGYNuclear FusionAnother %a$ #or a less stable nucleus to become more stable is b$ fusion.5.4 NUCLEAR ENERGYNuclear FusionIn a #usion reaction* t%o liht nuclei combine to #orm a hea!ier nucleus* releasin a !ast amount o# ener$ durin the process.5.4 NUCLEAR ENERGYNuclear FusionIn a #usion reaction* t%o liht nuclei combine to #orm a hea!ier nucleus* releasin a !ast amount o# ener$ durin the process. This process is accompanied b$ the release o# a hue amount o# ener$.5.4 NUCLEAR ENERGYNuclear FusionT%o e"amples o# #usion reactions75.4 NUCLEAR ENERGYNuclear Fusion2usion is much more di8cult to achie!e than fssion because the h$droen nuclei %ith positi!el$ chare repel each other.This e"plains %h$ #usion can onl$ occur at !er$ hih temperature such as #usion in the sun.And also ener$ released in nuclear #usion is !er$ much more than in nuclear fssion.5.4 NUCLEAR ENERGYEnergy in a nuclear reactionAccordin to 9instein* neither mass nor ener$ are conser!ed separatel$ but the$ can be e"chaned one #or the other and onl$ the total :mass+ener$; is conser!ed.A loss o# mass means that the mass has chaned to ener$.5.4 NUCLEAR ENERGYEnergy in a nuclear reactionThe relationship bet%een the mass and the ener$ is i!en b$ the e&uation7%here E < ener$ released* in 'oules (=)m < loss o# mass or mass de#ect* in 1c < speed o# liht < 3.00 " ,0> m s+,5.4 NUCLEAR ENERGY2mc E =Energy in a nuclear reaction9"ample ,5.4 NUCLEAR ENERGYa. 2ind the mass de#ect in(i) a.m.u.(ii) 1?, a.m.u. < ,.// " ,0+-@ 1 5 , eV < ,.// " ,0+,. =AEnergy in a nuclear reaction9"ample ,5.4 NUCLEAR ENERGYb. Calculate the amount o# ener$ released in(i) =(ii) eVEnergy in a nuclear reaction9"ample -5.4 NUCLEAR ENERGYEnergy in a nuclear reaction9"ample 35.4 NUCLEAR ENERGYGeneration of electricity5.4 NUCLEAR ENERGYA nuclear reactor produces tremendous amount o# ener$ throuh nuclear fssion. This ener$ is used to enerate o# electricit$.Generation of electricity5.4 NUCLEAR ENERGYThe uranium #uel is #ormed into ceramic pellets.Generation of electricity5.4 NUCLEAR ENERGY2ission enerates heat and is used to produce steam. The steam turns hue turbine blades.Generation of electricity5.4 NUCLEAR ENERGYAs the turbines turn* the$ dri!e enerators to produced electricit$.Generation of electricity5.4 NUCLEAR ENERGYBater is used to cool the structure o# the po%er plant.Generation of electricity5.4 NUCLEAR ENERGY(uclear reactors is a place %here a nuclear chain reaction %ill ta1e place.Generation of electricity5.4 NUCLEAR ENERGYThe neutrons produced in a fssion reaction are !er$ #ast neutrons. To slo% do%n the neutrons raphite as a moderator is used.Generation of electricity5.4 NUCLEAR ENERGYThe rate o# reaction is controlled b$ boron control rod %hich can absorb neutrons.Generation of electricity5.4 NUCLEAR ENERGYIn electric po%er plants* the reactors suppl$ the heat to produced steam %hich dri!es the turbine 6 enerators.5.4 NUCLEAR ENERGYREA$%N &%R '(E U$E %& NUCLEAR ENERGYIt is not e"pensi!eIt does not produce smo1e or carbon dio"ide and does not contribute to the reenhouse eCect.It produced hue amounts o# ener$ #rom small amounts o# #uel.It produced small amounts o# %aste.(uclear po%er is reliable.(uclear reactors can also be used in research and in the production o# medical and industrial isotopes.5.4 NUCLEAR ENERGYREA$%N AGA)N$' '(E U$E %& NUCLEAR ENERGYRadioacti!e %aste is haDardous.(uclear ener$ #rom uranium is no rene%ableThe #uel and %aste products ha!e to be constantl$ monitored to pre!ent abuse.A nuclear accident can be a ma'or disaster.5.4 NUCLEAR ENERGYhttps7EE%%%.$outube.comE%atchF!