Radioactive Waste Disposal

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Classification of Waste
$%
HAZARDOUS
WASTE
BIOHAZARDOUS
WASTE
RADIOACTIVE
WASTE

RADIOACTIVITY
Certain elements that compose matter emit
particles and radiations spontaneously. This
phenomenon is referred to as `radioactivity´
Three different kinds of rays-alpha, beta
and gamma rays are associated with
radioactivity
Decay Rates are measured as half-lives-the
time it takes for one half of any given
quantity of a radioactive element to
disintegrate

easured in Becquerel (Bq) units
1 Bq = 1 decay or disintegration per
second
Health risk is measured in terms of
rem or Sievert (Sv)
1 rem = 0.01 Sv = 10 mSv

Radioactive Waste
Waste, by definition, is any material
(solid materials such as process
residues as well as liquid and gaseous
effluents) that has been or will be
discarded as being of no further use
Waste that emits nuclear radiation is
radioactive waste.

Cause for Concern
%he stuff we are dealing with can´t go
away until it decays. You can
containerize it, solidify it, immobilize
it and move it , but you can´t make it
go away
- James D. Werner

Cause for Concern
Radioactive waste can be in gas,
liquid or solid form, and its level of
radioactivity can vary.
The waste can remain radioactive for
a few hours or several months or
even hundreds of thousands of years.
Because it can be so hazardous and
can remain radioactive for so long,
finding suitable disposal facilities for
radioactive waste is difficult.

Depending on the type of waste disposed,
the disposal facility may need to contain
radiation for a very long time.
Proper disposal is essential to ensure
protection of the health and safety of the
public and quality of the environment
including air, soil, and water supplies
Disposal of radioactive waste is a complex
issue, not only because of the nature of the
waste, but also because of the complicated
regulatory structure for dealing with
radioactive waste.

Classification Based on Origin
Spent nuclear fuel from nuclear reactors
High-level waste from the reprocessing of
spent nuclear fuel
Transuranic waste mainly from defence
programs
Uranium mill tailings from the mining and
milling of uranium ore
Low-level waste
Naturally occurring and accelerator-
produced radioactive materials

Spent Nuclear fuel from nuclear
reactors & High Level Waste
Operation of nuclear reactors results
in spent fuel
Spent fuel is stored in water pools at
the reactor site where it was
produced. The water removes leftover
heat generated by the spent fuel and
serves as a radiation shield to protect
workers at the site.
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Continued.
HLW is the liquid waste produced by
the reprocessing of spent fuel to
recover unfissioned uranium &
plutonium
HLW is now stored in underground
tanks or stainless steel silos
These facilities have begun programs
to solidify and structurally stabilize
the waste in preparation for disposal
at a national repository
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Transuranic Radioactive Waste
Originates from nuclear weapon
production facilties
"Transuranic" refers to atoms of man-
made elements that are heavier
(higher in atomic number) than
uranium
The most prominent element in most
TRU waste is plutonium
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Continued.
Emits high levels of penetrating
radiations -requires protective
shielding
Dangerous when small particles are
inhaled or digested
Long half life-half of the original
amount of plutonium- in the
waste will remain harmful after
,000 years
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Continued.
Disposal options include
Leaving it in place, monitoring it
Leaving it in place, improving containment
Removing, processing & disposing of the
waste in a repository
An underground, geologic repository called
the Waste Isolation Pilot Plant (WIPP)
excavated in a salt bed 100ft underground
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Uranium ill Tailings
Radioactive sand like materials that
remain after uranium is extracted by
milling ore mined from the earth
Important radioactive component of
uranium mill tailings is radium, which
decays to produce radon. Also
contains selenium, molybdenum,
uranium, and thorium.
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Continued.
Public are affected by tailings by
Diffusion of radon gas-lung cancer
Inhaling or ingesting small particles
Emission of gamma radiations
Dispersal by wind, water, leaching etc
Active & passive control measures to
limit radon emissions & protect
ground water
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Low Level Radioactive Waste
Significantly less radioactivity
ade up of isotopes having much shorter half
lives
Large amounts of waste contaminated with
small amounts of radio nuclides, such as
contaminated equipment (glove boxes, air
filters, shielding materials and laboratory
equipment) protective clothing, cleaning rags,
etc. constitute low-level radioactive waste.
Shallow & Land disposal methods
Waste pre-processing done to reduce waste
volume
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Naturally occurring & Accelerator
produced Radioactive waste
NOR generally contain radionuclides
found in nature
Discrete NOR has a relatively high
radioactivity concentration in a very
small volume
Diffuse NOR has a much lower
concentration of radioactivity, but a
high volume of waste
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Accelerator-produced radioactive
waste is produced during the
operation of atomic particle
accelerators for medical, research, or
industrial purposes
Radioactivity being short-lived, can
be stored in laboratories until it is no
longer radioactive
Continued.
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ethods of Disposal
Landfilling
Incineration
Geological Deposits
Sea Dumping
Ocean bed Dumping
Solar Dumping
Transmutation
Subductive Waste Disposal
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Landfilling of Low Level Waste
Engineered landfills, reinforced concrete
trenches are used
aximum quantity of radioactivity in
each container at the time of removal
from the premises is 0 Bq for
radionuclides with a half-life less than or
equal to days; Bq for
radionuclides with a half-life greater
than days, 0 Bq for carbon-1
and tritium
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Continued.
Waste shall be moved to the site in a
sealed container
It shall be buried in its container
beneath not less than 1. metres of
earth or ordinary waste
Wastes containing 1Cs, 1Cs, 0Sr,
0Co,n and H can be disposed by
landfilling

Incineration
Solid radioactive waste that is not suitable
for disposal to landfill because of other
hazardous properties, e.g. clinical waste,
can be authorised for disposal by
incineration at an authorised incinerator
During incineration of radioactive waste,
emissions which contain radioactive
particulate matter released into the air.
Hence when adapted, one uses fine
particulate filters and the gaseous effluents
are diluted and released

Geological Deposits
Geologic disposal in deep geological
formations -whether under continental
crust or under seabed - as a means of
radioactive waste disposal has been
recognized since 1, for handling long-
lived waste
The deep geological sites provide a natural
isolation system that is stable over
hundreds of thousands of years to contain
long-lived radioactive waste
Eg:Yucca ountain Repository

Yucca ountain High Level
Waste Repository
Located at Las Vegas, Nevada
Layers of consolidated, compacted ashfalls
from volcanic eruptions occurring more
than 10 million years ago
Underlying the tuff is sedimentary
carbonate rock
Repository horizon in `unsaturated zone´,
about 00 meters below the surface, and
00-00 meters above the water table
Two major aquifers in the saturated zone
below Yucca ountain, one in tuff, one in
carbonate rock


Sealed Storage Cask

Sub Sea Bed Disposal
Involve isolation of radioactive waste within a
geological strata
The floor of deep oceans is a part of a large tectonic
plate below the sea surface, covered by hundreds of
metres of thick sedimentary soft clay. These regions
are desert-like, supporting virtually no life.
The Seabed Burial Proposal envisages drilling these
`mud-flats´ to depths of the order of hundreds of
metres, such boreholes being spaced apart several
hundreds of metres.
The high-level radioactive waste contained in
canisters would be lowered into these holes and
stacked vertically one above the other interspersed

Ocean Bed Dumping
For many years the industrialized countries of
the world opted for the least expensive method
for disposal of the wastes by dumping them
into the oceans
Proposal for disposing of nuclear and asbestos
waste by means of Free-Fall Penetrators -
waste-filled missiles, which when dropped
through 000 m of water, will embed
themselves 0-0 m into the seabed´s clay
sediments. These penetrators are expected to
survive for 00 to 100 years. Thereafter the
waste will diffuse through the sediments.

Deposition hole for canister
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Solar Dumping
It is proposed that `surplus weapons´,
plutonium and other highly
concentrated waste might be placed
in the Earth orbit and then
accelerated so that waste would drop
into the Sun.
Involves vast technical development
Extremely high cost
Robust containment
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Transmutation
Use transmutational devices, consisting of a hybrid of
a subcritical nuclear reactor and an accelerator of
charged particles to `destroy´ radioactivity by
neutrons.
The fission fragments can be transmuted by neutron
capture and beta decay, to produce stable nuclides.
Transmutation of actinides involves several competing
processes, namely neutron-induced fission, neutron
capture and radioactive decay.
The large number of neutrons produced in the
spallation reaction by the accelerator are used for
`destroying´ the radioactive material kept in the
subcritical reactor.

Subductive Waste Disposal
Subduction is a process whereby one tectonic
plate slides beneath another and is eventually
reabsorbed into the mantle.
The subductive waste disposal method forms a
high-level radioactive waste repository in a
subducting plate, so that the waste will be
carried beneath the Earth´s crust where it will
be diluted and dispersed through the mantle.
It is the single viable means of disposing
radioactive waste that ensures non return of
the material to the biosphere

Nuclear Incidents-
Three ile Island
Three ile Island (TI ) is a nuclear plant
in iddletown, US.
The accident began about :00 a.m. on
arch , 1, when the plant
experienced a failure in the secondary,
non-nuclear section of the plant.
The main feedwater pumps stopped
running, which prevented the steam
generators from removing heat

The pressure in the nuclear portion
began to increase
Cooling water poured out of the stuck-
open valve and caused the core of the
reactor to overheat
The nuclear fuel overheated to the point
at which the zirconium cladding (the
long metal tubes which hold the nuclear
fuel pellets) ruptured and the fuel
pellets began to melt.

Small releases of radioactive gases were
measured off-site by the late morning of
arch
Estimates are that the average dose to
about million people in the area was
only about 1 millirem.
The maximum dose to a person at the
site boundary would have been less than
100 millirem.

Chernobyl Power Plant, Ukraine
On April , 1, during a testing operation,
one of the four reactors at the Chernobyl
nuclear power plant went out of control and
exploded.
Due to the explosion and subsequent 10-day
fire at the site large amounts of radioactive
substances (00 times that of bombing of
Hiroshima) were released into the atmosphere.
The major radioactive contaminants of concern
were iodine (11I) and caesium (1Cs and
1Cs).

The plume moved predominately northward and then
over western Europe. 0% of the radioactive material
was deposited over Belarus
All of the noble gases, including krypton and xenon,
contained within the reactor were released immediately
into the atmosphere by the first steam explosion.
About % of the radioactive iodine in the reactor was
released, as a mixture of vapor, solid particles and as
organic iodine compounds.
Caesium and tellurium were released in aerosol form
Two sizes of particles were released: small particles of
0. to 1. micrometers (aerodynamic diameter) and
large particles of 10 micrometers.

The large particles contained about 0% to
0% of the released nonvolatile radioisotopes
zirconium-, niobium-, lanthanum-10,
cerium-1 and the transuranic elements,
including neptunium, plutonium and the minor
actinides, embedded in a uranium oxide
matrix.
The total amount of radioactive material that
was released had an activity of millions Bq.
,000 Bq had a long half-life (caesium,
strontium and plutonium
Approximately million people who received
increased doses of radiation, per cent have
become ill.

Diseases of the cardiovascular and endocrine
system, the airways and gastrointestinal tract
predominate
Thyroid cancer in children, Leukaemia in
children and adults, Breast cancer and the
effects of radiation on pregnancy are common
Scandinavia, Poland, Czechoslovakia, Austria,
southern Germany and northern Italy- Within
these countries, the soil was contaminated to
varying degrees.
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Nuclear reactor after the disaster
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Conclusions
Radioactive and nuclear wastes being
fatal must be handled and disposed
with high care
It is thus our moral duty to reduce
such wastes and implement efficient
disposal options for waste disposal.

References
http://www.nei.org/keyissues/nuclearwaste
disposal/
http://www.dae.gov.in/rules/waste.pdf
http://www.nea.fr/html/rwm/reports/1/
progress.pdf
http://www.nrc.gov/reading-rm/basic-
ref/teachers/10.pdf
http://www.epa.gov/rpdweb00/rert/radiatio
nincidents.html
http://www.epa.gov/rpdweb00/rert/monito
ring.html