Nuclear Reactors

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Nuclear Reactors. What is fission again?. Nuclear reactors take advantage of the process of nuclear fission which splits an atom and releases a great deal of energy FP = Fission Product. Quick Review of Nuclear Plants. Different T ypes of Power Plants. In the US: Pressurized Water Reactor - PowerPoint PPT Presentation

Text of Nuclear Reactors

Nuclear Reactors II

Nuclear Reactors

What is fission again?Nuclear reactors take advantage of the process of nuclear fission which splits an atom and releases a great deal of energy

FP = Fission Product

Quick Review of Nuclear Plants

Different Types of Power PlantsIn the US:Pressurized Water ReactorBoiling Water ReactorIn general, most reactors are Generation II, such as the Fukushima Dai-ichi reactorsModern reactors are Generation III which are dramatically improved and more efficientSo-called passive safety measures which rely solely on natural laws such as gravity

Cut-Away of Peach BottomHow is Radiation Contained?The nuclear core is contained within a 3.9 to 7.9 ft thick pre-stressed, steel-reinforced, air-tight concrete dome to prevent escape

How is Waste Material Secured?Fuel can be replaced every 12-18 monthsTwo types of waste:Low-Grade: Refers to materials in contact with the fuel rods, directly or indirectlyHigh-Grade: Refers to the spent nuclear material and byproductSecured in underground pools and depots for several years in the plants or nearbyGeologists study naturally occurring fission processes to better understand how to dispose of waste materialWhat could go wrong?Damage to the core due to loss of coolingDue to loss of pressureDue to loss of coolantDue to uncontrolled power excursionNuclear MeltdownNot a technical term, but refers to the melting of nuclear material and a breach in the containment vessel

Worst-caseWhen:A limiting fault that leads to the failure of heat removal within the coreThe Emergency Core Cooling System(ECCS) failsThen the core would heat beyond its melting point and turn into corium causing a containment breach

Radiation in the EnvironmentIodine 129 and 131 are radioactive and can be absorbed by the body causing thyroid cancerAcute radiation syndromeStunted growth and death in local wildlifeIncrease in mutations in humans and other animalsGroundwater absorbs radionuclidesNaturally Occurring FissionFirst found in OkloinGabon, Africa by physicist Francis PerrinThese reactions occurred about 2 billion years ago, and were self-sustained for some hundred thousand yearsScientists are studying this process to better learn how radioactive material travels through the Earths crust and how to contain radioactive inert gases release

1. Nuclear reactor zones2. Sandstone3. Uranium ore layer4. Granite