Radioactive waste comes in low-level and high-level forms. Low-level waste includes slightly contaminated materials that are buried or stabilized in concrete. High-level waste is highly radioactive spent nuclear fuel, which is currently stored on-site at reactors in water pools or dry casks until a national repository opens. Managing radioactive waste safely and finding locations to dispose of it long-term continues to be a politically challenging issue due to public health concerns and NIMBY opposition.

1. Radioactivity & Waste

2. For more help contact me
Muhammad Umair Bukhari
Engr.umair.bukhari@gmail.com
www.bzuiam.webs.com
03136050151

3. Structure of the Atom
Nucleus
Neutrons
+ +
+
Protons
Electrons
(Electron Clouds)

4. Radioactivity
Definition
Any spontaneous change in the state of the nucleus
accompanied by the release of energy.
Major Types
alpha ( ) particle emission (decay)
beta ( ) particle emission ( -), positron
emission ( +) and orbital electron capture
(ec)
gamma ( ) decay including internal
conversion

5. Ionizing Radiation
Definition - Any type of radiation possessing enough
energy to eject an electron from an atom,
thus producing an ion.
Major Types of Ionizing Radiation Alpha, Beta, Gamma
Alpha Particle
Large Mass (nuclei) – Helium
+
+
Atom with a +2 charge
Beta Particle
Small Mass - Electron
(subatomic particle)
Gamma Photon No Mass
(Electromagnetic
and X-Rays
Radiation)

6. Decay
has a discrete energy that can be measured and
related to the parent. The neutron to proton ratio is to
low !
+ 4He Nucleus
+
Ejected from Nucleus
+
+ +
+
+ +2
+
+
This is radioactive!! Most of the energy
associated with
(monoenergetic)
238U 4He + 234Th

7. Decay
Either too many neutrons or too many protons
neutrino Change a neutron
into a proton
take away - charge
+
-
+
Electron (negatron)
+
+ +
+
+
+ anti-neutrino Change a proton
+ into a neutron
+ take away + charge
(positron)
3 products share energy – therefore beta has a continuous range of energies

8. Electron Capture
X-ray
Change proton into neutron
X-ray

9. Decay
• Emission of a photon from the nucleus
• Most often occurs after or emission when nucleus is left in an excited
state
• Given off with discrete energies
• Can measure photon energy and possibly identify parent
+
+ Gamma Photon
+
+ +
+
+
+
+
or
+2
-
neutrino

10. Radiation Dosimetry Units
Exposure, X:
amount of charge produced anywhere in air by the
complete stoppage of all electrons liberated by photons
in an incremental volume of air per unit mass of air in
that volume.
Standard International (SI) unit: Coulomb/kilogram (C/kg)
Traditional unit: roentgen ( R ) 1 R = 2.58x10-4 C/kg
Exposure definition applies only to photons of energy less than or
equal to 3 MeV interacting in air.

11. Radiation Dosimetry Units
Absorbed dose:
RAD
is the energy deposited by any type of ionizing radiation
in a volume element of mass.
SI unit: gray (Gy)
Traditional unit: rad 1Gy = 100 rad
Absorbed dose definition applies to all forms of ionizing
radiation in any material.

12. Relative Biological Effectiveness and
Quality Factor
Relative Biological Effectiveness (RBE)
( Biological effect of radiation Y at dose X
Biological effect of 250 kVp x-rays at dose X )
Both produce the same biological effect.
Quality factor (Q)
radiation Q
photon, 1
proton, neutron 10
alpha 20

13. Relative Biological Effectiveness
Ln (S)
Shoulder of curve indicates
cell repair at low doses
No shoulder - no cell repair
Effect
Same Biological Effect Dn D
Different Dose from 2
types of radiation
Dose

14. Radiation Dosimetry Units
Dose Equivalent
Dose equivalent: allows the description of the biological
effect of an absorbed dose of a particular type of radiation or
mixed radiations for the Human Body.
Dose Equivalent (DE) in Rem = Dose in Rads x Q
SI unit: sievert (Sv)
traditional unit: rem 1 Sv = 100 rem
millirem
For photons: 1 R 1 rad = 1 rem

15. PRECAUTIONS
FOR
AVOIDING UNNECESSARY RADIATION EXPOSURE

16. External Radiation Exposure
Definition: Exposure of the body from radiation
originating outside of the body
Level of Hazard and Control Depend Upon:
1. Type of Radiation (Alpha, Beta Gamma)
2. Energy of the Radiation (Low or high energy)
3. Dose Rate (Low or high dose rate)

17. Reducing External Radiation
Exposure
•Time:
reduce time spent in radiation area
•Distance:
stay as far away from the radiation source as possible
•Shielding:
interpose appropriate materials between the source and
the body

18. Radioactive Waste
We will discuss -
 Low Level Radioactive Waste
 High Level Radioactive Waste
 Mining Tailings

19. Radioactive Waste
Low Level Radioactive waste consists of
microcurie, millicurie and at times curie
activity waste.
(A Curie is a unit of nuclear transformations.
1 Curie is 3.7 x1010 transformations per
second)

20. Radioactive Waste
 Low level radioactive waste consists of:
– Contaminated solids
– liquids
– animal carcasses
– small sealed sources

21. Radioactive Waste
 Low level radioactive liquids are either:
– Incinerated
– Deep well injected (not as frequent anymore)
– Solidified
– Sewer Disposed (Regulations allow curie levels
of some isotopes to be sewer disposed of if
dilution is large enough)

22. Radioactive Waste
 Radioactive animal carcasses are either
incinerated or buried onsite.

23. Radioactive Waste
 Small sealed sources
are “Stabilized” in
concrete and buried.
Stabilized concrete is
concrete that is
certified to resist
wear for a certain
time period.

24. Radioactive Waste
 Low level
contaminated solid
wastes are buried.
GSU has it’s solid
waste
“Supercompacted”
at 30,000 psi to
reduce the volume to
be buried

25. Radioactive Waste
Most low level wastes come from Government
and Utilities. These consist of contaminated
solids from nuclear reactor usage and weapon
construction.

26. Radioactive Waste
 Colleges, research and medical applications
account for less than 25% of the low level
Radioactive wastes created

27. Radioactive Waste
 Class A low-level radioactive waste is the least hazardous,
containing mostly short-lived radionuclides that will be
reduced in radioactivity (decay) in a relatively short time.
It contains only small amounts of radionuclides that take a
relatively short time to decay. Class A waste will be
disposed of in concrete canisters that will maintain their
shape and strength for hundreds of years.

28. Radioactive Waste
 Class B low-level radioactive waste is more hazardous
than Class A waste. Most of it comes from nuclear
reactors. It must be in a stable form for disposal and will
also be disposed of in concrete canisters. Stabilization can
be accomplished by solidifying liquid waste, compacting
solid waste, or placing the low-level radioactive waste in a
container that will be stable for many years. Class B low-
level radioactive waste makes up only a small percent of
the waste volume generated; but along with Class C waste,
it contains the largest portion of the total radioactivity.

29. Radioactive Waste
 Class C low-level radioactive waste is the
most hazardous and must be handled
accordingly. It also must be disposed of in a
stable form.

30. Radioactive Waste

31. Radioactive Waste
 There are 3
LLRW
Burial sites:
– Hanford
– Envirocare
– Barnwell

32. Radioactive Waste

33. Radioactive Waste

34. Radioactive Waste
 Politics of LLRW
– Compacts
– On-site burial
– NIMBY

35. Radioactive Waste
 The compact system was set up by NRC to
have all states share in the responsibility of
disposal of radioactive waste and to limit
waste transport distance. Georgia is in the
Southeast compact.
 Until 1992, all states within the SE compact
(excluding Florida) would host a LLRW
landfill on a 20-25 year revolving timetable.

36. Radioactive Waste
 Kentucky was the first (Maxie Flats), then South
Carolina (Barnwell). In 1995, North Carolina was
to open a site but the citizens protested and sued.
The State legislature refused.
 North Carolina was then “kicked out” of the S.E.
compact and left with no place to dispose of
waste. Other States followed N.C.’s lead and
refused
 This lead to the collapse of the traditional compact
system and the

37. Radioactive Waste

38. Radioactive Waste
In the past, many Universities and
companies were allowed to bury their
radioactive wastes onsite. Some were
allowed to deep well inject liquid
radioactive waste.

39. Radioactive Waste
N.I.M.B.Y.
Not
In
My
Back
Yard
The true politics of Hazardous Waste

40. Radioactive Waste
Did North Carolina, by not
opening up a waste site, better
protect it’s citizens?

41. Radioactive Waste
 High-Level Radioactive Waste is: the
irradiated fuel from the cores of nuclear
reactors, the liquid and sludge wastes that
are left over after irradiated fuel has been
reprocessed (a procedure used to extract
uranium and plutonium), the solid that
would result from efforts to solidify that
liquid and sludge from reprocessing.

42. Radioactive Waste
Because there is
currently no high
level radioactive
waste disposal
facility, HLRW is
held On-Site in
water pools

43. Radioactive Waste
Once these
Pools are
full, Waste
is
transferred
to casks
which are
also held
on-site

44. Radioactive Waste

45. Radioactive Waste
A HLRW repository is
being constructed at
Yucca Mountain in
Nevada to hold all
this waste. NIMBY
again is playing a
role in the opening

46. Radioactive Waste
YOUR THOUGHTS
AND DISCUSSION