Nuclear Reactor : Nuclear Reactor Slide 2: NUCLEAR REACTOR
A nuclear reactor is a device in which nuclear chain reactions are initiated, controlled, and sustained at a steady rate, as opposed to a nuclear bomb, in which the chain reaction occurs in a fraction of a second and is uncontrolled causing an explotion. Nuclear Fission Reaction:- : Prentice-Hall © 2002 General Chemistry: Chapter 26 Slide 3 of 47 Nuclear Fission Reaction:- Fission: History and Overview : Fission: History and Overview Discovered 1938 Otto Hahn and Frittz Strassmann
Presented 1939 Lise Meitner Otto Frisch
Research of Nuclear Fission began U.S. Weapons Program
1942 First Controlled self sustaining fission reaction, Enrico Fermi
Nuclear Fission Creates electricity
Three types of nuclear energy, Fission reactions, Fusion reactions, andRadioactive decay Nuclear Fission Chain Reaction : 5 Nuclear Fission Chain Reaction Basic Diagram of a nuclear reactor : Basic Diagram of a nuclear reactor http://www.nrc.gov/ Piecing Together a Reactor : Piecing Together a Reactor Fuel
Cooling tower Slide 8: NUCLEAR FUEL
Nuclear fuel is any material that can be consumed to derive nuclear energy. The most common type of nuclear fuel is fissile elements that can be made to undergo nuclear fission chain reactions in a nuclear reactor
The most common nuclear fuels are 235U and 239Pu. Not all nuclear fuels are used in fission chain reactions Slide 9: CONTROL RODS
Control rods made of a material that absorbs neutrons are inserted into the bundle using a mechanism that can rise or lower the control rods.
. The control rods essentially contain neutron absorbers like, boron, cadmium or indium. Slide 10: STEAM GENERATORS
Steam generators are heat exchangers used to convert water into steam from heat produced in a nuclear reactor core.
Either ordinary water or heavy water is used as the coolant. Slide 11: STEAM TURBINE
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into useful mechanical
Various high-performance alloys and superalloys have been used for steam generator tubing. Slide 12: COOLANT PUMP
The coolant pump pressurizes the coolant to pressures of the orderof 155bar.
The pressue of the coolant loop is maintained almost constant with the help of the pump and a pressurizer unit. Slide 13: CONDENSER
Condenser is a device or unit which is used to condense vapor into liquid.
The objective of the condenser are to reduce the turbine exhaust pressure to increase the efficiency and to recover high quality feed water in the form of condensate & feed back it to the steam generator without any further treatment. Slide 14: COOLING TOWER
Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere.
Water cirulating through the codenser is taken to the cooling tower for cooling and reuse What Happens to Used Fuel? : What Happens to Used Fuel? Uranium in a nuclear reactor comes in the form of ceramic pellets.
Only one of the uranium isotopes fission, U-235. New fuel contains about 5% U35, the rest is U-238.
When most of the U-235 has split, the used-up or “spent fuel” is stored in a large pool to cool off. Dry Cask Storage : Dry Cask Storage After the fuel has “cooled”, it is moved into concrete casks.
Eventually, the fuel will be sent for permanent disposal deep under ground. Slide 17: ADVANTAGES
Nuclear power generation does emit relatively low amounts of carbon dioxide (CO2). The emissions of green house gases and therefore the contribution of nuclear power plants to global warming is therefore relatively little.
This technology is readily available, it does not have to be developed first.
It is possible to generate a high amount of electrical energy in one single plant Slide 18: DISADVANTAGES
The problem of radioactive waste is still an unsolved one.
High risks: It is technically impossible to build a plant with 100% security.
The energy source for nuclear energy is Uranium. Uranium is a scarce resource, its supply is estimated to last only for the next 30 to 60 years depending on the actual demand. Nuclear “Accidents” : Prentice-Hall © 2002 General Chemistry: Chapter 26 Slide 19 of 47 Nuclear “Accidents” Three Mile Island – partial meltdown due to lost coolant. Chernobyl – Fault of operators and testing safety equipment too close to the limit. France – safe operation provides 2/3 of power requirements for the country. Results of the Explosion : Results of the Explosion Conclusion : Conclusion So we can conclude that the nuclear energy is very help for next coming generation. But it must be implemented at best at safe level to prevent accendints. Thank You : Thank You