A TECHNICAL ANALYSIS
NUCLEAR WASTE
BY:Arpit Modh (16BCH035)B.Tech ChemicalNirma University,Ahmedabad.
Environment Studies
Nuclear Waste…WHY?• 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 Cycle..!Most 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.
Intermediate Level WasteILWIntermediate level waste requires shielding
when being handled.7% volume of wasteDependent on the amount of activity it can
be buried in shallow repositories. Not recognized in the United States.
High Level WasteHLWHigh 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, Np-237, U-236
High 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, Np-237, U-236
High Level WasteHLW
Transuranic WasteTRUWTransuranic 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 Waste• Nuclear 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.
Service Period Waste
Consists 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.
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
Treatment (LLW)FiltrationIon ExchangeEvaporationIncinerationCompactionSolidification
Waste Management (HLW)Most common utilized option are reactor
pools and dry cask storage.Other Options for waste management
include:Deep Geologoical StorageTransmutationReuseLaunching it into space
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.
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.
Transmutation of Nuclear WasteReduces transuranic waste. Integral Fast ReactorBanned 1977-1981 (U.S.)MOX Fuel
Behaves 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
ConclusionsHLW is most
dangerous byproduct of nuclear power.
Borosilicate glass most common storage.
Several venues being researched for the safe disposal of HLW.