Radiation Safety Principles
Osama Taqatqa
Radiation Safety Officer
Nuclear Engineering Department
May 6, 2014
12:30-2:00pm, Ibn-Al-Nafis Hall
Radiation Safety Officer: Osama Taqatqa
Outlines
-
Responsibilities of RSO
FANR (Federal Authority for Nuclear Regulation)
Introduction to Radiation
Units of Activity
Alpha, Beta, Gamma Radiation
Definitions
Background Radiation
Dose limits
ALARA
Radiation safety equipment
Radiation Safety Officer: Osama Taqatqa
Summary
What are the responsibilities of RSO?
The RSO is responsible for:
• Developing, reviewing, and implementing a Radiation Protection Program.
• Keeping careful records of all transactions regarding radioactive materials.
• Testing radioactive materials for leaks.
• Supervising the safe disposal of radioactive waste.
• Examining all personnel monitoring reports.
• Investigating any accidents or spills that involve radioactive materials.
• Training for employees, students and non-users on how to protect
themselves from radiation exposure.
Radiation Safety Officer: Osama Taqatqa
Safety is not just for users, but also for all
- We will be holding a training session lasting 2-4 days, in Fall 2014,
through the College of Engineering, for all.
- For all means for radiation workers, students, and non users.
- “Non users” means maintenance workers..., I’m now preparing
presentation “Awareness”, which will be translated to 4 languages,
in addition to Arabic and English.
Radiation Safety Officer: Osama Taqatqa
FANR
Federal Authority for Nuclear Regulation
Radiation Safety Officer: Osama Taqatqa
Introduction to radiation
Radiation: is energy in the form of moving particles or
electromagnetic waves.
There are two types of radiation:
- Non-ionizing radiation: does not have enough energy
to remove an electron from the atom or molecule.
Microwave, radio wave,…
- Ionizing radiation: Radiation with
enough energy to remove an electron
or more from the atom or molecule,
producing ions.
Alpha particles, Beta particles, gamma-rays, X-rays
Radiation Safety Officer: Osama Taqatqa
Radiation Safety Officer: Osama Taqatqa
Radioactivity
• The process by which unstable atoms
spontaneously transform into new atoms
and emit radiation during the process.
Radiation Safety Officer: Osama Taqatqa
Isotope & Radioisotope
• Isotopes: Atoms of the same element, that
contain the same number of protons, but
different number of neutrons.
• Radioisotope: unstable isotope of an element
that has radioactivity: undergoes spontaneous
decay, emitting radiation.
Radiation Safety Officer: Osama Taqatqa
Units of Activity
• Becquerel (Bq): 1 disintegration per second.
Henri Becquerel, French Physicist (1852-1908)
• Curie (Ci): 3.7X1010 disintegration per
second.
1mCi=37MBq
Radiation Safety Officer: Osama Taqatqa
Marie Curie, Polish Physicist(1867–1934)
Half-Life
The time required
for the activity to
reach one half of its
original value.
Radiation Safety Officer: Osama Taqatqa
Alpha Radiation
• Helium Nucleus.
• Most massive type of radiation.
• Alpha particles have a relatively
large electric charge, thus a very
strong interaction with matter.
Because of this they have a short
range.
• Hazardous only via ingestion or inhalation of alpha emitters
(Internal Hazard).
Radiation Safety Officer: Osama Taqatqa
Beta Radiation
Positively charged beta particles
(Positrons)
• Annihilation of radiation: The
interaction between beta particle
and the electrons from the
surrounding atoms, producing 2
gamma rays.
Negatively charged beta particles
(Electrons)
There are 2 main mechanisms
of interaction:
1- Ionization: The interaction
between the beta particle and the
orbital electrons of surrounding
atoms.
2- Bremsstrahlung
• External hazard to skin and eyes.
Radiation Safety Officer: Osama Taqatqa
Radiation Safety Officer: Osama Taqatqa
Bremsstrahlung: Bremsen-Strahlung
bremsen "to brake" and Strahlung "radiation
- Bremsstrahlung is caused by the deflection of high-energy electron by the electric
field of an atomic nucleus.
X-ray
K1
K1- K2=hv
e
-
K2
e
-
- Conservation of Energy: Some of the kinetic energy of the moving electron is converted
into a photon.
Radiation Safety Officer: Osama Taqatqa
Gamma rays and X-rays
- Photons
- No charge
- No mass
- Highly Penetrating
- External hazard to deep organs and tissues.
Radiation Safety Officer: Osama Taqatqa
Radiation Safety Officer: Osama Taqatqa
Definitions (1)
• Exposure (R): Amount of charge
produced per unit mass of air
from ionized radiation.
1 R = 2.58X10-4 C/kg
Wilhelm Röntgen (1845–1923) German
Physicist
• Absorbed Dose (Gy): Amount of
energy deposited per unit mass of
material (J/kg).
1 Gy = 100 rad
Radiation Safety Officer: Osama Taqatqa
(1905–1965) British Physicist
Definitions (2)
• Dose Equivalent (Sv):
The quantity DE (J/kg) is used to describe the human
health risk due to the exposure to radiation.
DE= D X WR
1 Sv = 100 rem
D: Absorbed dose
WR: Radiation Weighting Factor
For example:
For equal absorbed doses, alpha
particles could be 20 times more
damaging than beta particles.
Radiation Safety Officer: Osama Taqatqa
Rolf Sievert (1896–1966) Swedish Medical Physicist
Radiation Safety Officer: Osama Taqatqa
Example
• Calculate the dose equivalent:
-1 Gy of gamma rays.
DE (Sv) = WR x D (Gy)
= 1 X 1= 1 Sv
-1 Gy of Alpha
DE (Sv) = WR x D (Gy)
= 20 X 1= 20 Sv
Radiation Safety Officer: Osama Taqatqa
Definitions (3)
Effective dose (Sv):
Taking relative radiosensitivity of each organ and tissue.
E= DE X WT
DE: Dose Equivalent
WT: Tissue Weighting Factor
Radiation Safety Officer: Osama Taqatqa
Organ or tissue
Tissue weighting
factor (WT)
Gonads
Red bone marrow
Colon
Lung
Stomach
Bladder
Breast
Liver
Oesophagus
Thyroid
Skin
Bone surface
Remainder
0.2
0.12
0.12
0.12
0.12
0.05
0.05
0.05
0.05
0.05
0.01
0.01
0.05
Total
1.0
Radiation Safety Officer: Osama Taqatqa
Example
Colon was exposed to 5mGy of gamma rays,
Calculate the effective dose?
E= D X WR X WT
E= 5 mGy X 1 X 0.12
E= 0.6 mSv
Radiation Safety Officer: Osama Taqatqa
Background radiation
Source of exposure
Cosmic radiation
Directly ionizing and photon
component
Neutron component
Cosmogenic* radionuclides
Total cosmic and cosmogenic
Outdoors
Indoors
Total external terrestrial radiation
External terrestrial radiation
Annual effective dose (mSv)
Average
0.28
0.10
0.01
0.39
0.07
0.41
0.48
Uranium and thorium series
0.006
Radon (Rn-222)
Thoron (Rn-220)
Total inhalation exposure
K-40
Ingestion
Uranium and thorium series
1.15
0.1
1.26
0.17
Inhalation
Total ingestion exposure
Total
0.12
0.29
2.4
* Cosmogenic: rare isotope created when a high-energy cosmic-ray interacts with the nucleus.
Radiation Safety Officer: Osama Taqatqa
Radioactive levels (Intake)
Food
Radioactive levels (Bq/kg)
Daily intake
(g/d)
Ra-226
Th-228
Pb-210
K-40
Rice
Wheat
Pulses
150
270
60
0.126
0.296
0.233
0.267
0.270
0.093
0.133
0.133
0.115
62.4
142.2
397.0
Other
Vegetables
70
0.126
0.167
--
135.2
Leafy
Vegetables
15
0.267
0.326
--
89.1
Milk
90
--
--
--
38.1
Composite
Diet
1370
0.067
0.089
0.063
65.0
Radiation Safety Officer: Osama Taqatqa
Radiation Safety Officer: Osama Taqatqa
To USA = 5µSv/h X 14 h= 70 µSv
Radiation Safety Officer: Osama Taqatqa
Recommended dose limits
Application
Effective dose
Occupational
20 mSv per year
the lens of the eye
150 mSv
the skin
500 mSv
the hands and feet
500 mSv
Investigation Levels:
- Quarterly Investigation Levels (3 months)
Based on 2.5 % of any applicable occupational limit.
- Annual Investigation Levels ( 12 months)
Based on 10 % of any applicable occupational limit.
Radiation Safety Officer: Osama Taqatqa
Public
1 mSv in a year
20 mSv
Basic principles of radiation protection
Justification
of Practice
Optimization
of Protection
Individual dose
limits
Radiation Safety Officer: Osama Taqatqa
ALARA
As Low As Reasonably Achievable
Each Individual is responsible for ensuring that his or
her exposures are kept “ALARA”.
HOW
Reduce TIME in radiological area
Increase DISTANCE to radioactive material
Use a suitable SHIELD between you and sources of radiation
Radiation Safety Officer: Osama Taqatqa
Three basic factors for protection
Use a suitable SHIELD between you and sources of radiation
Radiation Safety Officer: Osama Taqatqa
plastic
Lead
Beta Source
Bremsstrahlung x-ray
The intensity of Bremsstrahlung x-rays increases with increasing
atomic number of absorber.
Radiation Safety Officer: Osama Taqatqa
Gamma or x-ray
Lead
Because of its high density, and large
number or electrons, LEAD is a very good
medium for scattering x-rays and
gamma-rays.
Radiation Safety Officer: Osama Taqatqa
Suitable Shield of Neutron Source
- The most effective shielding materials are
hydrocarbons, e.g. polyethylene, paraffin wax ,
or water.
- Light atoms slow down the neutrons by elastic
scattering, so that they can then be absorbed.
Radiation Safety Officer: Osama Taqatqa
Reduce TIME in radiological area
10mGy/h
Total Dose= Exposure rate X Time
1 hour
= 10mGy/h X 1 h = 10mGy
2 hour
= 10mGy/h X 2 h = 20mGy
Radiation Safety Officer: Osama Taqatqa
Increase DISTANCE to radioactive material
???? mSv
40 mSv
50 cm
150 cm
E1 X (d1)2 = E2 X (d2)2
40 X (50)2 = E2 X (150)2
E2 = 4.4 mSv
Radiation Safety Officer: Osama Taqatqa
E2= E1 X (d1)2
(d2)2
Radiation Safety Equipment
(Personal Monitoring)
Radiation Safety Officer: Osama Taqatqa
Radiation safety equipment
(Workplace Monitoring)
Radiation Safety Officer: Osama Taqatqa
Signage
Radiation Warning Sign
Radiation Safety Officer: Osama Taqatqa
Summary
- Radiation Workers & NE students are required to review and
understand IAEA Safety Standards.
- You should keep your exposures “ALARA”.
- To understand the basics of safety, you
must know how to use UNITS.
- Always use radiation safety equipment,
and comply with the approved dose limits.
- Always make SAFETY your No.1 on the list.
- Be ready for training in fall, 2014.
Radiation Safety Officer: Osama Taqatqa
Radiation Safety Officer: Osama Taqatqa
Thank you for your very kind
attention
http://www.safetypostershop.com/
Radiation Safety Officer: Osama Taqatqa