Name:  ______________________________________  Block:  ___________  Date:  ______________________________  

Science  10:  Fission  and  Fusion   1  

      Science  10:  Radioactivity!

Comparing Fission and Fusion Notes  (Ch  11)    http://www.atomicarchive.com/Movies/index.shtml      Nuclear Reactions:  an  atom’s  nucleus  changes  by  gaining  or  releasing  particles  or  energy.    Protons,  neutrons,  electrons  and/or  gamma  rays  can  be  lost  or  gained.      There  are  small  changes  in  mass  and  really  big  changes  in       .        How  are  nuclear  reactions  different  from  chemical  reactions?        Radioactive  decay  (alpha,  beta,  gamma)  occurs  naturally,  but  scientists  can  force  a  nuclear  reaction.    This  is  called  an            nuclear  reaction.    A  nucleus  is  bombarded  with  alpha  particles,  beta  particles  or  gamma  rays  causing  it  to  become  unstable  and  force  it  to  undergo                 .    Example:  

   *Important…  The  sum  of  the  mass  numbers  on  both  sides  of  the  equation  stays  the  same.  The  sum  or  the  charges  (atomic  numbers)  on  both  sides  of  the  equation  stays  the  same.    Questions  A:  

Name:  ______________________________________  Block:  ___________  Date:  ______________________________  

Science  10:  Fission  and  Fusion   2  

 Nuclear  FISSION:  the            of  nuclei.    One  heavy  nucleus  is  split  into  two  or  more          nuclei,  some  sub-­‐atomic  particles  and         .    A  heavy  nucleus  is  usually  unstable,  due  to  many                  repelling  each  other.      When  fission  occurs,            is  produced  and            are  released.    

   Equation:      þ          must  equal  on  both  sides  of  the  equation.  þ          must  equal  on  both  sides  of  the  equation.    Nuclear  fission  is  used  to  produce  energy  in                and           .    Nuclear  Power  Plant:  

Chapter 7 The atomic theory explains radioactivity. • MHR 319

CANDU ReactorsCanada is a leader in the peaceful use of nuclear technology for bothmedical uses and for power generation. Canadian nuclear reactors arecalled CANDU reactors. CANDU stands for “Canadian deuteriumuranium” reactor. Deuterium is an isotope of hydrogen-1 that is twice asheavy as it has both a proton and a neutron in its nucleus.

The design of the CANDU reactor is among the safest in the world,and the reactor can be shut down quickly if a problem arises. Canadaprovides nuclear power technology and expertise to other countries tohelp them establish nuclear power generation stations.

Figure 7.23 shows eight CANDU reactors at the Pickering NuclearGenerating Stations. A diagram of the inside of each reactor is shown inFigure 7.24. The reactor core produces heat as a result of reactions likethe following:

10n ! 235

92U ➔ 9236Kr ! 141

56Ba ! 3 10n ! energy

Nuclear power plants and fossil-fuel burning power plants are similarin that both produce a lot of heat. This heat is used to boil water andgenerate steam, which then drives the turbines that produce electricity. Aturbine is a large rotating device that can be forced to turn when steam isapplied to it. You may recall from earlier science studies that a turbinedrives a generator that produces electricity.

Did You Know?CANDU reactors use heavywater—water in which thehydrogen atoms are deuterium—

as both moderator andcoolant.

Figure 7.23 The Pickering Nuclear Generating Stations inPickering, Ontario, include eight separate reactors. All arevisible in the photo.

reactor building

reactor

steamgenerator

steam

fuel-loadingmachine

turbine building

turbine

circulating water

generator

Figure 7.24 The nuclear fuel produces heat, which isused to make steam. The stream drives turbines that areconnected to electrical generators.

BCS10_C07_F 3/11/08 4:55 PM Page 319

   Questions  B:  

   

 

 

Name:  ______________________________________  Block:  ___________  Date:  ______________________________  

Science  10:  Fission  and  Fusion   3  

 Nuclear  Fission:  Chain  Reactions    Chain  reaction:  one  reaction  starts  the  next  reaction,  which  starts  the  next  reaction  and  so  on.    This  can  be  used  to  create  nuclear  power.    This  process  must  be  monitored  very  closely  so  that  it  does  not  get  out  of  control.    

         

Nuclear FUSION:  the          of  nuclei.    Two  light  nuclei  are  joined  into  one               .    In  the  core  of  the  sun,  two  hydrogen  nuclei  join  under  lots  of  heat  and  pressure  to  form  a        nucleus.    When  the  helium  atom  is  formed,  huge  amounts  of  energy  are  released.    

  Equation:  

 Scientists  cannot  yet  find  a  safe,  manageable  method  to  harness  the  energy  of  nuclear  fusion.    So-­‐called  “            “  would  occur  at  temperatures  and  pressures  that  could  be  controlled.      

Name:  ______________________________________  Block:  ___________  Date:  ______________________________  

Science  10:  Fission  and  Fusion   4  

 Nuclear Equations for Fission and Fusion  1.  Categorize  the  following  reactions  as  fission  or  fusion  by  circling  the  fission  reactions.  

 2.  What  elements  are  typically  found  in  fission  reactions?      3.  What  elements  are  typically  found  in  fusion  reactions?      4.     a)  What  is             ?          

b)  What  type  of  reaction  is  it  found  in  and  is  it  a  reactant  or  product?      5.  Summarize  the  major  difference  between  fission  and  fusion  reactions.                        6.  For  the  following  reactions  identify  them  as  fission  or  fusion  and  fill  in  the  missing  isotopes.  

 

Name:  ______________________________________  Block:  ___________  Date:  ______________________________  

Science  10:  Fission  and  Fusion   5  

 Comparison of Fission and Fusion Reactions  

   

Chapter 7 The atomic theory explains radioactivity. • MHR 321

A large facility is being builtin California to producefusion in a drop of liquidhydrogen. Powerful lasersare to be directed into abubble of hydrogen, causingthe outside of the bubble toexplode and the inside toimplode. The shock of theexplosion should cause heatand pressures similar towhat is found in the centresof stars. This process iscalled inertial confinementfusion. Find out more atwww.bcscience10.ca.

Fusion nuclear equationThe nuclear equation for fusion in the Sun and in fusion reactionexperiments is:

21H ! 3

1H ➔ 42He ! 1

0n ! energy

Researchers have worked for over half a century to find a technologythat will allow us to extract energy from fusion reactions. One of thedifficulties is achieving the high temperatures and pressures needed.Another is simply finding a way to contain a reaction that is so hot thatno vessel can hold it without being destroyed. Fission and fusionreactions are compared in Table 7.11.

Did You Know?

Due to its constant output ofenergy, the Sun loses almost 4 million tonnes of mass each

second as the mass isconverted to energy.

Table 7.11 Comparison of Fission and Fusion Reactions

Fission Reaction Fusion Reaction

Heavy unstable nuclei split apart Two lightweight nuclei join together into two smaller nuclei. to form a heavier nucleus.

Unstable nuclei release a huge Lightweight nuclei release a huge amount of energy when they split. amount of energy when they join.

Heavy nuclei will not release excess Lightweight nuclei will not release energy by splitting if they are as light excess energy if the nucleus generatedas the element iron or lighter. by fusing is heavier than iron.

Fission reactions often produce daughter Fusion reactions often do not produceproducts that are radioactive. This causes products that are radioactive. This a radioactive waste problem for nuclear makes nuclear fusion reactors an energy production. attractive possibility for nuclear

energy production.

Many countries, including Canada, No commercial fusion reactorsgenerate some electrical power are in use or under construction.through fission reactions.

Research continues to try to produce Research continues to try to environmentally friendly nuclear produce a fusion nuclear reactor.power generation.

A fission reaction is used in modern nuclear A fusion reaction is used in modern weapons by itself or to produce an nuclear weapons to generate most of explosion that will generate sufficient heat the energy released in the blast. A and pressure to trigger a fusion reaction. fusion reaction needs the heat and

pressure from a fission nuclear explosion to get it started.

Equation of a typical reaction: Equation of a typical reaction:

10n ! 235

92U ➔ 9236Kr ! 141

56Ba !3 10n ! energy 21H ! 3

1H ➔ 42He ! 1

0n ! energy

BCS10_C07_F 3/11/08 4:55 PM Page 321