Slide 1

Chapter 25 Nuclear Chemistry 25.3 fission and Fusion of Atomic Nuclei

Slide 2

Chemistry Today we are learning to:- 1. Describe what happens in a nuclear chain reaction 2. Explain the use of water in the storage of spent fuel rods 3. Distinguish fission reactions from fusion reactions

Slide 3

When the nuclei of uranium-235 or plutonim-239 are bombarded with neutrons, they undergo fission, the splitting of a nucleus into smaller fragments. The steps are as follows: i.A slow moving neutron strikes a uranium-235 nucleus ii.The nucleus splits into two roughly equal halves iii.3 more neutrons are released iv.These neutrons start a chain reaction with other uranium-235 nuclei Nuclear Fission Fission and Fusion of Atomic Nuclei

Slide 4

Nuclear Fission Fission and Fusion of Atomic Nuclei

Slide 5

Nuclear Fission Fission and Fusion of Atomic Nuclei Chain Reaction Video

Slide 6

Nuclear Power Fission and Fusion of Atomic Nuclei Indian Point Energy Center is a three-unit nuclear power plant station located in Buchanan, New York just south of Peekskill NY.

Slide 7

Half-Life

Slide 8

Neutron moderation is a process that slows down neutrons so the reactor fuel (uranium-235 or plutonium-239) captures them to continue the chain reaction. Water and graphite are good moderators Neutron absorption is a process that decreases the number of slow- moving neutrons. Control rods, made of a material such a cadmium, are used to absorb neutrons. Nuclear Power Fission and Fusion of Atomic Nuclei

Slide 9

Why are spent fuel rods from a nuclear reaction stored in water? They are highly radioactive and dangerous to the environment Water keeps spent fuel rods cool Water acts as a radiation shield, absorbing dangerous radiation Nuclear Waste Fission and Fusion of Atomic Nuclei

Slide 10

Nuclear Fusion Fission and Fusion of Atomic Nuclei Fusion occurs when nuclei combine to produce a nucleus of greater mass. In solar fusion, hydrogen nuclei (protons) fuse to make helium nuclei and two positrons. Fusion reactions, in which small nuclei combine, release much more energy than fission reactions, in which large nuclei split. The sun has been supplying energy via nuclear fusion for about 4.567 billion years, and is about half way through its life cycle

Slide 11

The use of controlled fusion as an energy source on Earth is appealing as the potential fuels are inexpensive and readily available. The problems with fusion lie in achieving the high temperatures necessary to start the reaction (40,000,000,000 C) and in containing the reaction once it has started. Nuclear Fusion Fission and Fusion of Atomic Nuclei

Slide 12

2.3 Vocabulary 25.3 Vocabulary Fission: the splitting of a nucleus into smaller fragments Neutron moderation: process of slowing down neutrons do they will be absorbed by nuclei. Neutron absorption: process of decreasing the number of slow moving neutrons by using control rods Fusion: when light nuclei fuse together to form a single nuclei

Slide 13

END OF SHOW