nucular waste managment

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Nucular Waste Managment Faisal Sadaat

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Presentation on Nuclear waste management.

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Nucular Waste Managment

Nucular Waste ManagmentFaisal Sadaat

Radioactivityalpha () particle emission (decay)

beta () particle emission (-), positron emission (+) and orbital electron capture (ec)

gamma () decay including internal conversionDefinitionAny spontaneous change in the state of the nucleus accompanied by the release of energy.Major Types

WHAT CONCERNS DO WE HAVE ABOUT THE NUCLEAR FUEL STORAGE AND TRANSPORTATON?

Nuclear WasteWhy?Recently nuclear power has entered many discussions as world energy needs rise and oil reserves diminish. Most opponents of nuclear power point to two main arguments: meltdowns and nuclear waste.Nuclear waste is any form of byproduct or end product that releases radioactivity.How to safely dispose of nuclear waste is pivotal for the continued operation of nuclear power plants, safety of people living around dump sites, and prevention of proliferation of nuclear materials to non-nuclear states. Nuclear Fuel CycleMost nuclear waste comes from the byproducts of the nuclear fuel cycle. The cycle typically is split into three sections: front end, service period, and back end. There can be intermediate stages that include the reprocessing of nuclear waste elements.

Nuclear Fuel Cycle (Cont.)

ClassificationsNuclear waste is segregated into several classifications.Low level waste is not dangerous but sometimes requires shielding during handling.Intermediate level waste typically is chemical sludge and other products from reactors.High level waste consists of fissionable elements from reactor cores and transuranic wastes.Transuranic waste is any waste with transuranic alpha emitting radionuclides that have half-lives longer than 20 years.Low Level WasteLLWLow level waste is any waste that could be from a high activity area.90% volume of wasteIt does not necessarily carry any radioactivity.Split into four catagories: A, B & C.What about Low-Level Waste?Class ASoil and building debrisContaminated tools and equipmentContaminated clothes and glovesIon exchange resin from liquid cleanupClass B and CSmoke detectors and exit signsMedical WasteActivated MetalsMedical Research MaterialsManufacturing Materials

Intermediate Level Waste ILWIntermediate level waste requires shielding when being handled.7% volume of wasteDependent on the amount of activity it can be buried in shallow repositories. High Level Waste HLWHigh level waste has a large amount of radioactive activity and is thermally hot.3% volume of waste95% of radioactivityCurrent levels of HLW are increasing about 12,000 metric tons per year.Most HLW consists of Pu-238, 239, 240, 241, 242, U-236Transuranic Waste TRUWTransuranic waste consists of all waste that has radionuclides above uranium. TRUWs typically have longer half-lives than other forms of waste.Typically a byproduct of weapons manufacturing.Only recognized in the United States.Creation of Nuclear WasteNuclear waste is generated at all points of the fuel cycle.Front end waste consists primarily of low level alpha emission waste.Service period waste typically includes LLW and ILW such as contaminated reactor housings and waste from daily operation.Back end waste normally is the most radioactive and includes spent fuel rods and reactor cores.Front End WasteFront end waste consists mostly of LLW and ILW.The primary front end waste is depleted uranium and radium. DU has several uses due to its high density (19,050 kg/m3).Mix with uranium to form reactor fuelService Period WasteConsists of mostly ILW.Mostly waste produced at the plant during normal operation.Spent fuel rods are the most dangerous waste produced during the service period.Back End WasteNuclear waste developed during the back end of the fuel cycle is the most dangerous and includes most of the HLW produced.Most back end waste emits both gamma and beta particles.Also uranium-234, neptunium-237, plutonium-238 and americium-241are found in back end waste.

Spent nuclear fuel in a cooling pond in NorthKorea.

Waste Management (LLW)There are several options available for the disposal of LLW due to its lack of radioactivity.Waste Isolation Pilot PlantOn-site disposal

Map of WIPP FacilityTreatment (LLW)FiltrationIon ExchangeEvaporationIncinerationCompactionSolidification

Typical LLW treatment facility.Waste Management (HLW)Most common utilized option are reactor pools and dry cask storage.Other Options for waste management include:Deep Geological StorageTransmutationReuseLaunching it into spaceLocations of storage sites for nuclear waste in the U.S.

TreatmentMost common initial treatment of waste is vitrification.Waste is first mixed with sugar and then passed through a heated tube to de-nitrite the material.This material is then fed into a furnace and mixed with glass.The molten glass mixture is poured into steel cylinders and welded shut.Treatment (Cont.)Mid level active waste is commonly treated with ion exchangeProcess reduces the bulk volume of radioactive material.Typically, mixed with concrete for a solid storage form.Treatment (Cont.)Synroc is a new method for storing nuclear waste developed in 1978 by Ted Ringwood.Attempts to hold radioactive material in a crystalline matrix.Currently in use for military waste management at Savannah River Site.Can hold 50%-70% volume of waste.Deep Geological RepositoryMost common method for handling nuclear waste.Typically kept separate from actual plants and buried far below ground.First used in 1999 in the US.Current research is focusing on Yucca Mountain.

Yucca Mountain SiteTransmutation of Nuclear WasteReduces transuranic waste. Integral Fast ReactorBanned 1977-1981 (U.S.)MOX FuelBehaves as low-enriched uraniumResearch now in subcritical reactors.Fusion also being researched.Reuse of Nuclear WasteResearch is being performed to find uses for nuclear waste.Caesium-137 and strontium-90 already used in industrial applications.Some waste can be used for radioisotope thermoelectric generators (RTGs). Overall can reduce total HLW but not eliminate it.Launch it into SpaceNear infinite storage spaceCompletely removes waste from biosphereTechnical risks and problemsPolitical entanglements

NIMBY: Not In My Back YardFear of radiation because they dont understand itConcern that the waste facility willrelease long-term contaminationWorry that property values will be reducedwith construction of a waste facilityBelief that power companies are the ones responsible for storing their own wastePeople dont want dumped on by otherpeoples wasteBelief that nuclear power should just goaway and be replaced by other energyresourcesEnvironmental concerns

ConclusionsHLW is most dangerous byproduct of nuclear power.Borosilicate glass most common storage.Several venues being researched for the safe disposal of HLW.