DISPOSAL OF RADIOACTIVE WASTE

VADIVELAN 2013111107SIDHAARTH 2013111118SAI KRISHNA 2013111122

NUCLEAR WASTE

• Composed of Radionuclides• Low, Medium and High level wastes• High level wastes produced in nuclear reactors consists of

oFission products(short-half lives)oActinides(long-half lives)

CLASSIFICATIONS

• Nuclear waste is segregated into following classificationsoLow level waste which is not dangerous but sometimes requires shielding

during handling.o Intermediate waste typically is chemical sludge and other products from

reactors.oHigh level waste consists of fissionable elements from reactor core.oTransuranic waste is any waste with transuranic alpha emitting radionuclides

whose half-life is longer than 20 years.

WASTE VOLUME

LOW LEVEL WASTE (LLW)

• Contains VERY LOW concentration of radioactivity.• Waste which does not require shielding during normal handling and

transportation.• 90% volume of waste.

INTERMEDIATE LEVEL WASTE (ILW)

• Intermediate level waste contains higher radioactivity levels than low level wastes.• Waste which requires shielding but needs little or no provision for heat

dissipation during its handling and transportation.• Intermediate level waste typically is chemical sludge, resins etc.• 7% volume of the waste.

HIGH LEVEL WASTE (HLW)

• High level waste has a large amount of radioactive activity and is thermally hot.• 3% volume of waste.• 95% of radioactivity.• Current levels of HLW are increasing at about 12,000 metric tons per

year.• Most HLW consists of Pu-238, 239, 240, 241, 242, Np-237, U-236.

BASIC STEPS AND ACTIVITIES IN RADIOACTIVE WASTE MANAGEMENT• Waste generation occurs during the operational period. It can be in the form of solid, liquid or

gaseous waste.• Pretreatment is the initial step that occurs just after generation. It consists of collection, segregation,

chemical adjustment and decontamination.• Treatment involves changing the characteristics of the waste. Basic treatment concepts are volume

reduction, radionuclide removal and change of composition.• Conditioning involves those operations that transform radioactive waste into a form suitable for

handling, transportation, storage and handling.• Storage facilities maybe co-located with a nuclear power plant or licensed disposal facility. • Retrieval involves the recovery of waste packages from storages either for inspection purpose or

further storage in a disposal facility.• Disposal consists of the authorized emplacement of packages of radioactive waste in a disposal

facility.

DISPOSAL OF LOW LEVEL WASTE

NEAR SURFACE DISPOSAL:• Disposal in a facility consisting of engineered channels or vaults constructed

on the ground surface or up to few tens of meters below ground level.• These type of wastes loses most or all of its radioactivity within 300 years.• It includes contaminated equipment from the operation of nuclear power

plant like clothing, rags, tools and equipment.• Very short-lived low-level radioactive waste such as that from hospitals,

universities and industry generally contains only small amounts of radioactive materials with short half-lives. This means that radioactivity decays away in hours or days.

DISPOSAL OF LOW LEVEL WASTE

DISPOSAL OF INTERMEDIATE LEVEL WASTE

• Depending on its characteristics, intermediate level radioactive wastes can be disposed in facilities of different types.• Disposal could be by emplacement in a facility constructed in caves,

vaults or silos at least few hundred meters below the ground level.• Intermediate level radioactive wastes require long-term management.• These are much bulkier materials and are first sealed in steel drums

and are encased in concrete trenches.

DISPOSAL OF INTERMEDIATE LEVEL WASTE

DISPOSAL OF HIGH LEVEL WASTE

GEOLOGICAL DISPOSAL:• A deep geological repository is a nuclear waste repository excavated

deep within a stable geologic environment.• Most long-lived radioactive wastes are stored here.• The volume of these HLW can be reduced by Nuclear reprocessing.

This reprocessing does not eliminate the need for a repository, but reduces the volume.• These repositories are at least a few hundred meters below the ground

level.

DISPOSAL OF HIGH LEVEL WASTE

DEEP BOREHOLES

• Deep borehole disposal is the concept of disposing high-level radioactive waste from nuclear reactors in extremely deep boreholes instead of in more traditional deep geological repositories that are excavated like mines.• Similar concept to geological repositories.• Kilometers deep rather then hundreds of meters.• Provide further insulation from ground water.

DEEP BOREHOLES

LAUNCH INTO SPACE

• Near infinite storage space.• Completely removes waste from biosphere.• High technical risks and problem of space vehicle failure.• High energy cost of space launch.• The current cost to launch an object into orbit around the earth is about

$20,000 per kilogram.

LAUNCH INTO SPACE

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