The document discusses sources of radiation, natural and man-made, and outlines safety procedures for radiography operations. It notes that radiation comes from cosmic, terrestrial, and internal sources. For radiography work, safety equipment like dosimeters, barricades, signs, and certified radiography workers are required to limit exposure and ensure safe operation. Regular monitoring and training are also needed to protect radiography workers.

1. Radiography Safety

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What Are the Sources of Radiation?
 Ionizing Radiation Exposures
 At work or home, on board a plane or train, in the
mountains or ocean – wherever we go we are always
exposed to small detectable doses of radiation that
cause no harm. The sources of this radiation are
divided into natural and manmade. This dose is
called background radiation that is an integral factor
of life.

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Natural Sources of Radiation
We are constantly bombarded by cosmic
radiation from space, similar to a steady
drizzle of rain. Charged particles from the
sun and stars interact with the Earth’s
atmosphere and magnetic field to produce a
shower of radiation, typically beta and gamma
radiation.
What Are the Sources of Radiation?

4. 4
What Are the Sources of Radiation?
 Small amounts of radioactive material are also found
naturally in soil, water, and vegetation. Some of these
materials can be ingested with food and water, while
others, such as radon gas, are inhaled. Certain
earthen building materials such as clay bricks, cement
blocks and wood can also have detectable amounts of
radiation that has been absorbed from the environment.
Your dose from these terrestrial sources varies in
different parts of the world, depending upon local
geology and many other factors.
 In addition to the cosmic and terrestrial sources, all
people have radioactive potassium-40, carbon-14, and
other isotopes inside their bodies from birth.

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Man-Made Sources of Radiation
 Both the general public and radiation workers receive exposure
from manmade radiation sources.
 Sources of manmade radiation exposures include:
 Medical Procedures - Diagnostic x-rays, nuclear medicine, and
radiation therapy.
 Consumer products - Tobacco, television screens, luminous
watches dials, smoke detectors, fluorescent lamp starters,
camping lantern mantles, Airport X-ray systems.
 The public is also exposed to shipments of radioactive materials
and residual fallout from nuclear weapons testing and accidents,
such as Chernobyl.
 We all receive a total background radiation dose of about 360
millirems (mREM) or 3.6 milliSievert (mSv) per year,
approximately 81% percent from natural sources and 19 % from
manmade sources. These small natural and artificial background
radiation doses are not different in any kind or effect.

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Man-Made Sources of Radiation
 Above this background level of radiation exposure,
Radiation Regulations require that licensees to limit
maximum radiation exposure to individual members
of the public to 100 mREM (1 mSv) per year, and
limit occupational radiation exposure to adults
working with radioactive material to 50 mSv per year.
 Protecting personnel from harmful ionizing radiation
exposure is only possible through complying with
international radiation safety requirements.

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Non-Destructive Testing (NDT)
Non-Destructive testing (NDT) has a number of
important roles to play in ensuring the through-life
quality and reliability of many important products
whose integrity is of paramount importance. The
traditional role of NDT in quality control during
manufacture - predominantly defect detection - has
been complemented in recent years with
increasingly important inspections in-service on plant
and equipment at varying stages through life. The
correct application of NDT can prevent accidents,
save lives, protect the environment and avoid
economic loss.

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Non-Destructive Testing (NDT)
 To achieve these objectives there is a need to
manage NDT operations to ensure that they are safe
to use. Many of the necessary controls are available
through the “Site Radiography Procedure“ such as;
 Training and Certification for the Radiography
Workers
 Medical Examination
 Equipment Certification
 Personal Alarm System and Exposure monitoring
devices (Film Badge, Dosimeter, Bleeper Radiation
Alert)
 Radiation Monitoring Equipment (Survey meter)

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Radiography Workers
 All personnel performing radiographic work shall be
licensed and approved by the appropriate
Government authorities. Documentation proving a
valid license and government approval shall be
examined prior to allowing any work to proceed.
 Licensed approved contractors shall establish post,
maintain, and monitor perimeter barricades that will
limit personnel exposure outside the barricade to 2
MR/HR (milliroentgens per hour) or less.

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Radiography Operation
 When using this equipment, one thing is paramount
above all else – the radiographer must have and use a
fully calibrated and functional radiation monitor at all
times. Radiography cameras are mechanical devices
and there is always a possibility of a malfunction.
 Before use, the camera must be checked with a
monitor to ensure that the source is in the camera.
 When the source is wound out, the site must be
monitored to ensure no person is exposed.
 When the source is retracted, the site must be
monitored to ensure that the source has been retracted.
The camera must be monitored to ensure that the
source is in the camera.

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Radiography Operation
 There are certain statutory requirements governing the
design and use of isotope cameras.
 They cannot be closed or locked unless the source is fully
retracted.
 They must include an effective locking device.
 When loaded with a source, the radiation level at any point
5 cm from the surface must not exceed 2000μSv/hr
(microsievert per hour), and the radiation level at a distance
1 m from the external surface must not exceed 100μSv/hr.
 It must be durably marked with the radiation hazard symbol
(tre-foil), and the words “Caution – Radioactive Material”
and a number of additional details that will allow the source
to be identified in the event of an accident.

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Radioactive Symbol

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Radiography Operation
 Working distance from an exposed source is critical to
minimize radiation dose
 Wind-out cameras are provided with a cable that is
sufficiently long enough to enable the operator to
control the source from a location where the dose rate
is as low as practicable. The national code requires
that this control cable is at least 10 m long
 The guide tube and hose must be placed so that the
source is propelled away from the operator and the
general public as it emerges from the container

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Radiography Operation
The operator is closest to the source at the moment it
leaves the container during wind-out, and again as it is
re-enters the container during retraction. This operation
of winding out and retracting should be done quickly,
but without undue haste that could lead to damage of
the winding mechanism.

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Radiography Operation
Tungsten Collimator
 The far end of the guide tube should incorporate a collimator
made from a heavy metal such as tungsten. This device directs
the radiation in a beam towards the item to be radiographed,
and provides shielding in other directions.
 Safe working distance depends largely upon the use and
effectiveness of shielding devices such as collimators during a
gamma ray exposure.
 The national code of practice states that the maximum dose
rate at the boundary of an exposure area is 25μSv per hour.

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Radiation Exposure Controls
Radiation Monitoring
Equipment (Survey
meter)
 An equipment use to to
determine the
presence and intensity
of radiation; the units
normally in mREM or
μSv/hr (microsievert
per hour)

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Radiation Exposure Controls
Radiation Alert (Bleeper )
 Audible alarms are devices that emit a
short "beep" or "chirp" when a
predetermined exposure has been
received. It is required that these electronic
devices be worn by an individual working
with gamma emitters. These devices
reduce the likelihood of accidental
exposures in industrial radiography by
alerting the radiographer to dosages of
radiation above a preset amount. Typical
alarm rate meters will begin sounding in
areas of 450-500 mR/h. It is important to
note that audible alarms are not intended
to be and should not be used as
replacements for survey meters.

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Radiation Exposure Controls
Direct Reading Dosimeter
(DRD) & Digital Electronic
Dosimeter (DED)
 Pocket dosimeters are used
to provide the wearer with an
immediate reading of his or
her exposure to x-rays and
gamma rays. As the name
implies, they are commonly
worn in the pocket. The two
types commonly used in
industrial radiography are the
Direct Read Pocket
Dosimeter and the Digital
Electronic Dosimeter.

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Radiation Exposure Controls
Film Badge is a dosimeter
used for monitoring
exposure to ionizing
radiation. The badge
requires two parts to be
effective: photographic film,
and a holder
 Record all radiography
exposure level
 Develop and replace every
month
 Mandatory for all
Radiography workers

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Radiation Exposure Controls
Additional Safety Equipments that needs to be install
to prevent and inform other personnel that a
Radiography works is in progress;
 Barricade
 Warning Signs
 Beacon lights
Note: Standby watchman shall also be provided if
necessary

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Radiation Exposure Controls
Beacon Light or
Warning Light
 A bright rotating
warning light to warn
other personnel that a
hazards is present.
 Two different color
Beacon lights are some
times use to determine
if the area is safe or
unsafe or area is clear
from radiation

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Radiation Exposure Controls
Barricade Tape
 Barricades shall be erected,
based on calculations, at a
distance from the source of
radiation where levels are 2
MR/HR or less.
Tape/barricade on posts at
waist level is an acceptable
barricade. The barricade
shall consist of 2" wide
yellow tape with a magenta
stripe or with radiation
symbol.

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Radiation Exposure Controls
Warning Signs
 Standard "Danger-
Radiation Area" signs
shall be placed on all
sides of the barricade in
conspicuous places and
at probable entrance
points.

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Source Container
 Requirements:
 It shall be durably marked with an accepted radiation
hazard symbol and the words "DANGER RADIOACTIVE".
This durable marking shall be made so as to remain
legible if the container is subjected to damage as a result
of a vehicle accident or fire.
 It shall be resistant to toppling, rolling or impact.
 It shall be provided with suitable lifting devices or
attachments.
 It shall bear a firmly attached metal plate durably marked
with the data of the Subcontractor's name and telephone
number.

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Source Container
 Firmly attached plate marked with the maximum
equivalent activities (of specified radioisotopes) which
may be kept in the container preferably expressed in
an appropriate form such as 'Rating Curie's cobalt 60'.
This information shall be given for all radioisotopes,
which the Subcontractor may wish to place in the
container.
 The identification markings of the sources in the
container.
 Tagging of the source container with a removable tag
is not allowed.

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Source Camera
Radioisotopes must be
handled in shielded
containers to prevent
exposure of operators and
the general public to
ionizing gamma rays. In
years gone by, these
containers were
constructed from lead, as it
is a dense metal with high
absorption of gamma rays.

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Source Camera
 All radioisotope cameras used by the NDT industry are the remote
controlled type. The national code of practice requires that these
cameras be essentially safe, whether they are operated manually
or by power (electrical or hydraulic).
 A wind-out camera is one where the radioisotope source is moved
from the shielded container to an exposure position outside of the
container. The most common form of operation is a Bowden cable
fitted to a mechanical winding handle. This cable is attached to a
pigtail fitted behind the radioisotope holder, and the source is
wound forward through a guide tube or hose to its exposure
position. A collimator is normally fitted over the hose at the
exposure position to absorb most of the radiation that is emitted in
directions not required for the exposure.
 There are two basic types of wind-out cameras:
 The S-tube
 The straight tube

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Source Camera
The S-tube type
 In the shielded position, the source is locked in
the centre section of the S-tube. Radiation
travels in straight lines and so cannot escape.

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Source Camera
The straight tube
 The straight through type of wind-
out camera must include shielding
directly behind and directly ahead
of the radioisotope while it is in the
stored position. Hence, the pigtail
on these cameras is often made
from articulated segments of
tungsten or depleted uranium so
that they are sufficiently flexible to
travel around bends, and a plug or
a shutter drops into place ahead of
the isotope when the camera is
closed. These cameras
incorporate several safety
interlocks to prevent accidental
opening.

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Source Camera
The Pigtail
 The pigtail consists of the source holder, a connecting
device and a wire cable joining the two. When not in
use, the connector is locked by a clamping device to
prevent accidental movement of the source.

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Permit To Work
 Radiography Permit to Work shall be secure prior to any
Radiography works. Area must be clear for any unauthorized
personnel.
 Close coordination should me made with the Site Emergency
Response Team or Site Radiography Officer.
 A Permit to Work is a communication aid to ensure that all parties
involved in carrying out the work are consulted on the mitigation
to be carried out before the work is to start until such time that the
place of work is left in a safe state upon completion.
 The object of the permit to WORK system is to ensure that written
permission and authorization is given to carry out the defined
WORK which is potentially hazardous and that all possible
measures are taken to maintain the safety of the personnel and
equipment in all areas of operation.

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Summary
 The sources of radiation can be natural and manmade.
 Radiography or NDE works is safe as long it will be
done according to Safe procedure.
 Different types of Safety equipments are essential
during Radiography Operation.
 Proper Training, Certification for the Radiographer and
close Supervision is a must during this operation
 Regular Film Badge monitoring and medical check-up
is a must for radiographer