NUCLEAR CHEMISTRY: Fundamental Concepts, Nuclear Fission & Fusion Dr. N. K. Shukla Associate Professor Department of Chemistry Mahatma Gandhi P.G. College Gorakhpur-273001

AN INTRODUCTION TO FISSION & FUSION

Introduction The reactions in which nuclei of atom interact with another nuclei or elementary particles such as alpha particle, proton, neutron ,deuteron etc. resulting in the formation of a new nucleus and one or more elementary particles are called Nuclear Reactions. In all the nuclear reaction the total number of neutron and proton are conserved .

Various Types of Nuclear Reactions Projectile Capture Reaction Particle-particle Reactions Spallation Reaction Fission Reaction Fusion Reaction The focus of this presentation are the processes of Nuclear fission and Nuclear fusion Both fission and fusion processes deal with matter and energy

Matter and Energy Earlier studies have taught us that “matter and energy cannot be created nor destroyed” We now need to understand that Matter and Energy are two forms of the same thing

E = mc2 Matter can be changed into Energy Einstein’s formula above tells us how the change occurs In the equation above: E = Energy m = Mass c = Speed of Light (Universal Constant) Energy Mass Light Speed

E = mc2 The equation may be read as follows: Energy (E) is equal to Mass (m) multiplied by the Speed of Light (c) squared This tells us that a small amount of mass can be converted into a very large amount of energy because the speed of light (c) is an extremely large number

Fission Fission may be defined as the process of splitting an atomic nucleus into fission fragments The fission fragments are generally in the form of smaller atomic nuclei and neutrons Large amounts of energy are produced by the fission process

Fission Fissile nuclei are generally heavy atoms with large numbers of nucleons The nuclei of such heavy atoms are struck by neutrons initiating the fission process Fission occurs due to electrostatic repulsion created by large numbers of protons within the nuclei of heavy atoms

Fission A classic example of a fission reaction is that of U-235: 92U235 + 1 Neutron = 2 Neutrons + 36Kr92 + 56Ba142 + Energy In this example, a stray neutron strikes an atom of U-235. It absorbs the neutron and becomes an unstable atom of U-236. It then undergoes further fission.

Fission The fission process is an a natural one as a French researcher found a natural uranium reactor in Gabon, West Africa; it has been estimated to be over 2 billion years old Fission produces large amounts of heat energy and it is this heat that is captured by nuclear power plants to produce electricity

+ ENERGY

Fusion Fusion is a nuclear reaction whereby two light atomic nuclei fuse or combine to form a single larger, heavier nucleus The fusion process generates tremendous amounts of energy For fusion to occur, a large amount of energy is needed to overcome the electrical charges of the nuclei and fuse them together

Fusion Fusion reactions do not occur naturally on our planet but are the principal type of reaction found in stars The large masses, densities, and high temperatures of stars provide the initial energies needed to fuel fusion reactions The sun fuses hydrogen atoms to produce helium, subatomic particles, and vast amounts of energy

REFERENCES Source Book on Atomic Energy- S. Glasstone Modern Physical Chemistry- R.P. Rastogi, K. Singh, K. Kishore, V.K. Srivastava & M.L. Srivastava Essentials of Physical Chemistry- Arun Bahl, B.S. Bahl & G.D. Tuli Principles of Physical Chemistry – Puri, Sharma & Pathania