AboutOsman Kemal Kadiroglu Expertise Nuclear Engineering, Nuclear Engineering Education, Nuclear Reactors, Pebble Bed Modular Reactors, Engineering Education
Experience Has been teaching Nuclear Engineering for more than 20 years and been in this field for more than 30 years
Organizations belong to American Nuclear Society
Society of Nucelar Engineers of Turkey
Emeritus Prof. Nuclear Engineering Department, Hacettepe University Ankara Turkey
Extra-ordinary Prof. Nuclear Engineering Department, North-West Uni. Potchefstroom South Africa
Education/Credentials (Mak. Y. Müh.) MS in Mech. Eng. Istanbul Technical University '68
MS in Nuclear Eng. MIT'72
Sc.D. in Nuclear Eng. MIT'76
Question Is nuclear power environmentally safer than coal power and why?
Answer Dear Basi,
I would like to apologize for my delay, I was in Lesbos, Greece for more than a week and did not have Internet connections there. I hope my replay is not too late and useless.
Naturally, nuclear power is much more better than the fossil fired plants. When one burns any kind of hydrocarbon, may it be oil, coal or gas, one produces exhaust gases like CO2, NOx, SO2 etc. and ash. If gas is used there will not be any ash but CO2 and, depending on the properties of the gas source, some amount of SO2 are produced. If the combustion happens at high temperatures then NOx is produced as well. If oil or coal is burned similar gases are produced as well as ash containing various metals like poisonous Cadmium, and radioactive uranium. The composition and amount of gases and metal compounds produced by burning fossil fuels changes with the type and quality of the fuel and the combustion methods. In short all the fuel one puts into the fossil fuel fired plant comes out in a form that is dangerous to the environment.
CO2 and Methane are important gases that increases the atmospheric temperature due to green house effect. SO2 is the main cause of the acid rain. (Lakes in Finland were effected by the British coal fired plants!) NOx is produced at high temperature combustion in Diesel engines and gas turbines, effect the ozone layer. Ash from a large coal fired plant produces ash mountains yearly. Ash has many heavy elements, radioactive elements and poisonous elements in it.
Nuclear power plants use uranium as the fuel. Uranium is fission in the reactor core and during this process heat is generated as well as many many isotopes. Most of those isotopes are extremely radioactive and thus extremely dangerous. That is why all nuclear facilities are build with "defense in depth" philosophy. The fuel is ceramic and thus will reduce the amount of leakage from the fuel to outside. Ceramic fuel pellets are housed in a stainless steel pressure tube called the fuel cladding. This is the second barrier. The whole fuel rods are housed in a pressure vessel of 25cm thick. This is the third barrier. The whole nuclear reactor is housed in a 2 meter thick steel/concrete containment vessel. During the normal operations no harmful radioactive material will ever be released to the environment. The only discharge from a nuclear power plant is the condenser water which is not radioactive at all. Once in a while some radioactive gases and liquids in very small amounts that will not cause harm to environment is released under control with the permission of the regulating agency.
During an accident thing could go really bad as it did in Chernobyl accident. A very similar accident that happened years before Chernobyl, the Three Mile Island accident, on the other hand proved that even in case of a worst case accident no harmful effects are inflicted on the environment. TMI accident released no harmful gases or liquids during and after the accident.
The only harmful effect nuclear power plants have on the environment is the so called thermal pollution. Nuclear power plants have lower operating temperatures (300C versus 600C for fossil fired plants) and thus lower thermal efficiencies (0.33 versus 0.45). A 1000MW electricity producing nuclear power plant ejects approximately 2000MW heat to the environment. (New nuclear designs that are inherently safe and has thermal efficiencies around 0.5 are being tested.)
Based on these facts I would say nuclear power is much safer for the environment.
