Presentation includes a brief introduction of radiation and its types, processing and disposal methods of different radioactive waste and a note on nuclear accidents.

1. Radioactive pollution- Ionising radiation, disposal of
radioactive waste, nuclear accidents

2.  Radiation is energy travelling through space.
 Energy can be transported either in form of
electromagnetic waves (radiations) or a stream of
energetic particles, which can be electrically charged or
neutral.
 These radiations are of two types :
(1) Non-ionizing radiations
(2) Ionizing radiations

3. Non-ionizing radiation
 Non-ionizing radiations are the electromagnetic waves of
longer wavelength from near ultraviolet rays to radio
waves.
 These waves have energies enough to excite the atoms
and molecules of the medium through which they are
moving, causing them to vibrate faster
 These do not have enough energy to ionize them.
 Non-ionising radiation does not penetrate deep into the
tissues but increases the risk of damage to the skin and
eyes.

4. Ionizing radiations
 Ionizing radiations are the electromagnetic radiations
having high energy, such as short wavelength ultra
violet radiations, x-rays and gamma rays.
 The energetic rays like produced in radioactive decay
can cause ionization of atoms and molecules of the
medium through which they pass and convert them
into charged ions.
 Alpha (), beta () and gamma () radiations are
produced by the process called radioactive decay.
 The unstable nuclei decay spontaneously and emit
these radiations.

6. Radioactive Pollution
 Living organisms are continuously exposed to a variety of
radiations called background radiations.
 If the level of the radioactive radiations increases above a
certain limit it causes harmful effects to living beings.
 This harmful level of radiations emitted by radioactive
elements is called radioactive pollution.

8. Disposal of radioactive waste
 Radioactive waste is generated from a variety of
industries.
 Any waste that contains or contaminated with radioactive
materials are called as radioactive waste.
 They can be generated from operation and discharging of
nuclear facilities, radionuclides using industry,
radionuclides containing raw material, medicine and
research.
 Radioactive waste is also generated during the cleanup of
sites affected by radioactive residues from various
operations or accidents.

9.  Radioactive waste arises from many different activities:
 Operation and discharging of nuclear facilities (e.g. nuclear
power plants)
 Application of radionuclides in industry, medicine, and research
 Cleanup of contaminated sites
 Processing of raw materials containing naturally occurring
radionuclide

10. Classification of Radioactive waste
Low level waste (LLW)
 Waste that is above clearance levels, but with limited amounts
of long lived radionuclides are categorized as LLW.
 Contains VERY LOW concentration of radioactivity.
 Waste which does not require shielding during normal handling
and transportation.
 LLW is generated from hospitals and industry, as well as the
nuclear fuel cycle.

11. Intermediate level waste (ILW)
 Waste that particularly of long lived radionuclides, requires a
greater degree of containment and isolation than that provided
by near surface disposal.
 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.

12. High level waste (HLW)
 Waste with levels of activity high enough to generate
significant quantities of heat by the radioactive decay process
or waste with large amounts of long lived.
 High level waste has a large amount of radioactive activity and
is thermally hot.
 HLW is produced by nuclear reactors
 Current levels of HLW are increasing at about 12,000 metric
tons per year.
 Most HLW consists of Pu-238, 239, 240, 241, 242, U-236.

14. Disposal of Radioactive Waste
 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.

15.  The following options can implement for radioactive
waste disposal
 Deep geological repositories
 Under water disposal i.e. Ocean dumping mainly
 Seabed burial
 Sub-seabed disposal
 Subductive waste disposal method
 Transforming radioactive waste to non-radioactive stable waste
 Dispatching to the Sun.

16. 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.

18. 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.

20.  Generally used for intermediate and high level waste from
a spent fuel pool is sealed (along with an inert gas) in a
steel cylinder, which is placed in a concrete cylinder
which acts as a radiation shield.

21. 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.

24. Deep boreholes
 Disposing of high-level radioactive waste from nuclear
reactors in extremely deep boreholes.
 Placing the waste as much as five kilometres beneath the
surface of the Earth.
 Waste is sealed in strong steel containers and lowered
down the borehole, filling the bottom one or two
kilometres of the hole.
 Borehole is then sealed with materials, including perhaps
clay, cement, crushed rock backfill, and asphalt, to ensure
a low- permeability.

26. Nuclear accidents

27.  Nuclear accidents can expose large populations to
dangerous levels of radioactivity, triggering enormous
liabilities for the firm responsible.
 Some Serious nuclear accidents are
 Fukushima Daiichi.
 Chernobyl.
 Three Mile Island.
 Enrico Fermi Unit 1
 SL-1.
 Sodium Reactor Experiment.
 Windscale.

28. Fukushima Daiichi, Japan
 The meltdown at the Fukushima
Daiichi Nuclear Plant on 11th
March 2011, is one of the worst
nuclear disasters in the world
history.
 The accident which occurred
following a huge earthquake and
a 15-metre tsunami left over a
million people displaced.
 While the number of direct deaths
from the incident are estimated to
be zero, around 1,600 people died
due to stress and evacuation
procedures.

29. Chernobyl, Ukraine (former Soviet Union)
 World's worst nuclear disaster till
date and classified as Level 7 on
INES (International Nuclear
Events Scale), the nuclear accident
at Chernobyl happened due to a
sudden rush in power during a
reactor system test in the Reactor
No. 4.
 It is estimated that approximately
2,00,000 people had to be
relocated from their homes to
escape the massive amounts of
harmful radiations and 31 people
died as a direct result of the
accident.

30. Three Mile Island, USA
 The 1978 accident at the
Three Mile Island nuclear
power plant in Pennsylvania
was the worst disaster in the
history of US.
 Although, the accident
claimed no lives and released
only little radioactive
radiations, it did provoke an
outcry over the country's
nuclear energy program.

31. Mayak or Kyshtym, former Soviet Union
 A fault in the cooling system at
the nuclear complex near
Chelyabinsk resulted in a
chemical explosion in 1957 and
the release of an estimated 70 to
80 tonnes of radioactive material
into the air.
 Thousands of people were
exposed to radiation and were
evacuated from their homes.
 Within a few days of the
accident, 300 residents died of
radiation poisoning. This
accident was categorized as
Level 6 on the 7 point INES.

32. Windscale, UK
 A fire in the graphite-core
reactor at Cumbria in 1957
resulted in a limited release of
radioactivity.
 The reactor was later buried in
concrete.
 Whereas no deaths have been
directly linked to this accident,
it did cause 200 cases of cancer
in Britain.
 This accident was categorised
as Level 5 on the seven-point
INES.