NUCLEAR POWER

What is Nuclear Power? Process of harvesting energy stored in atoms Used to produce electricity Nuclear fission is the form of nuclear power in use today

Structure of an Atom Nitrogen (N) 7 protons 7 neutrons 7 electrons

The Reaction Neutrons bombard the nuclei of atoms (U235 and Pu239) Energy released used to heat water High pressure steam used to spin turbines that generate electricity Rate of reaction controlled by control rods –Boron or cadmium –Fuel rods contain pellets of radioactive fuel

Uranium 235 Neutrons bombard Uranium- 235 Uranium-235 nucleus absorbs a neutron to be a uranium-236, it splits into two Some neutrons are emitted and a huge amount of energy Does not always split into Ba and Kr but usually into two fragments with almost equal masses The emitted energy is not always constant, but is almost 200 MeV.

Nuclear Fission Reactor

Pros and Cons of Nuclear Power Pros –Large fuel supply –Low environmental impact –Cheaper than many other forms of energy –Only moderate land disruption and use –Low risk of accidents Cons –Nonrenewable –Spent fuel rods must be stored in cement bunkers for 240,000 yr –Costly to remove and recycle remaining waste stored for 10,000 years –Target for terrorists

Aged Nuclear Reactor When a nuclear reactor reaches the end of its useful life, its highly radioactive materials must be kept from reaching the environment for thousands of years. At least 228 large commercial reactors worldwide (20 in the U.S.) were scheduled for retirement by –Many reactors are applying to extend their 40- year license to 60 years. –Aging reactors are subject to embrittlement and corrosion.

Nuclear Power in the US There are 61 commercially operating nuclear power plants with 99 nuclear reactors in 30 states in the United States. Thirty-five of these plants have two or more reactors Cost averaged 2.4 cents per kilowatt hour, about 1/3 the cost of a new natural-gas fired plant,1/4 the cost of a new onshore wind unit.

Nuclear Power in the US Nuclear Power Plants are being decommissioned ahead of schedule EX: San Onofre Power Plant located in North San Diego County closed in 2013 –Leak detected in a new steam generator –Will lead to rising costs of electricity –Will lead to increased carbon emissions as natural gas will replace nuclear power

Nuclear Accidents Three Mile Island, Harrisburg, PA –March 1979 –Mechanical and human error –Partial meltdown in reactor core released radioactive gasses into atmosphere –Reactor unusable and unapproachable for more than 10 years

Nuclear Accidents Tokaimura Criticality Accident, Japan –September 30, 1999 –Untrained workers, 2 died –Nuclear fission chain reaction ran out of control Fukushima Daini Nuclear disaster 2011 –Earthquake and tsunami –Water overwhelmed the seawall and flooded generators causing failure & meltdowns –18,500 died in earthquake and tsunami –Deaths directly because of radiation –Possible increase in thyroid cancers in children

The Chernobyl Accident April 26, 1986 Series of explosions blew off one of the reactors and released radioactive debris Radioactive cloud moved around Russia and parts of Europe, eventually around the globe

Chernobyl: How did the Accident Happen? Engineers running unauthorized experiments Turned off controls Reaction ran out of control No secondary containment Explosion

Chernobyl: The Effects 100X radioactivity released by US atomic bomb dropped on Hiroshima in WWII 100,000+ people had to abandon contaminated homes, farms, animals Most people were not evacuated for 10 days following the explosion Thyroid cancer among children, birth defects, other unknown effects in future

Future of Nuclear Power MIT report: – "The nuclear option should be retained precisely because it is an important carbon-free source of power." –Fossil fuel-based electricity is projected to account for more than 40% of global greenhouse gas emissions by 2020 –In the U.S. 90% of the carbon emissions from electricity generation come from coal-fired generation, even though this accounts for only 52% of the electricity produced. –Nuclear energy limited by four unresolved problems: high relative costs perceived adverse safety, environmental, and health effects potential security risks stemming from proliferation unresolved challenges in long-term management of nuclear wastes.

Bibliography “Control the Nuclear Power Plant.” 20 Nov Nov “Energy Information Administration.” Nov Four reactors picture. ons/4/4e/Nuclear_Power_Plant_Cattenom.jpg&imgrefurl= d.blogspot.com/2007_03_01_archive.html&h=1536&w=2048&sz=283&hl=en&start=6 &um=1&tbnid=Av1Hzs8mNXi- bM:&tbnh=113&tbnw=150&prev=/images%3Fq%3Dnuclear%2Bpower%2Bplant%26s vnum%3D10%26um%3D1%26hl%3Den%26safe%3Dactive%26rls%3Dcom.microsof t:en-us%26sa%3DN&safe=on. 20 Nov “How Nuclear Power Works.” 20 Nov MIT. “Future of Nuclear Power.” 20 Nov Reactor picture Nov Several Nuclear Power Plants Retiring Early. others-at-risk/ 7 Apr others-at-risk/ “Solcomhouse.” 20 Nov