Radio Graphic Inspection

8/6/2019 Radio Graphic Inspection

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RADIOGRAPHICINSPECTION:

Radiography is the process for detecting discontinuities in test

objects by passing ionizing radiation through them and recording

the transmitted radiation pattern on Radiographic films.

This is a well-established technique, which gives a permanent

record and widely used to detect internal flaws in a welded

specimen,casting,assemblies.



The radiation sources used for industrial radiography

can be Gamma ray sources and X-ray machines.

Characteristics of Gamma Ray sources:

Source Half Life

IRIDIUM-192 74d

Cobalt-60 5.26yCesium-137 30y

Thorium-170 127d

CHARECTERISTICS:



For X-ray sources, it needs electric power and

continuous cooling arrangement as it get heated up.

Energy and intensity can be controlled by controlling KV

andmA.The higher the voltage, the greater the penetrating power

of the radiation. Industrial x-ray equipment ranges from

about 20kv to 20MV and the most powerful equipment can

be used to radiograph up to 500mm steel.



Radiation units used to determine radiation hazard:

1.Strength of the source:

The old unit Curies (Ci) and new unit is Bequerel (Bq).

1 Curie = 3.7x1010 disintegrations/sec

1 Bequerel = One transmission/sec

1 Curie-37G Bq (G stands for Giga=109

)2.Exposure Rate:

Exposure rate gives the radiation level (X and Gamma rays) at any point and

place in air.

Exposure® = Exposure rate (R/hr) x time (hr)

3. Dose:For all types of radiation it gives the energy deposited or absorbed in any

medium. Its unit is radian.

4.Dose equivalent:

The dose equivalent gives the biological effect. The unit of dose equivalent is

rem.



General Safety Measures

Always wear film bandage while handling radiation sources.Check the functions of radiography cameras routinely.

Keep radiography sources securely and safely to avoid any

theft or misplacement.

Do not stand near a source unnecessarily.

Keep full inventory of all the sources at the site.

Always use proper handling tools and accessories for safe

handling of sources.In case of unusual occurrences (damage to camera) inform

RP&AD,BARC,MUMBAI promptly.



Don'ts

Do not allow an unqualified person to handlethe camera.

Do not sit on the wooden box carrying the

camera with radiography source.Do not handle the camera roughly and

carelessly.



TRANSPORT INDEX(TI)

Number expressing the maximum radiationlevel in mR/hr. at 1M from surface of the

package.



Category-I

Whitelabel:

Radiation level on the surface of the package is less than 0.5

mR/hr.



Category-II YELLOW LABEL:

Radiation level on the surface-0.5 mR/hr. to 50 mR/hr.

Radiation level at 1M from the surface of package is lessthan 1mR/hr.



Category-III YELLOWLABEL:

Radiation level on the surface-50 mR/hr. to 200 mR/hr.

Radiation level at 1M from the surface of package 10

mR/hr.



PERMISSIBLE LEAKAGE LEVEL AROUND

RADIOGRAPHY CAMERAS

( as per ISO 3999)

CLASS

Maximum exposure rate

nA/kg (mR/h)

On external surfaceof container 50 mm from externalsurface of container 1 m from externalsurface of container

PORTABLE 14.3(200) or 3.6 (50) 0.1 (2)

MOBILE 14.3(200) or 7.2 (100) 0.4 (5)

FIXED 14.3(200) or 7.2 (100) 0.7 (10)



Camera Storage Room



Specific Safety Procedures:

Work Practices:

Cameras must be operated only by certified Radiographers.Radiography should be carried out during little or No occupancy

around (Night time/Day time with restricted scale).

An appropriate area around the radiation source must be cordoned

off.The distance to be cordoned off is determined by the type and

strength of radiation, which can be monitored by suitable & calibrated

radiation survey meter.

Radiation warning symbols must be displayed along cordon.The placard and the radiation symbol should be readable from a

distance of 6 to 7 meters under normal illumination.

Red warning lights must be conspicuously displayed during night

along the cordon.



Specific Safety Procedures:

Suitable supporting and fastening devices must be used for hoisting

and positioning radiography cameras/X-ray machines in order toavoid mishaps.

Making use of the shielding provided by the body of the equipment

& camera should be operated by positioning oneself behind the

machine.After termination of each exposure, it must be verified by means of

a radiation survey meter in proper working condition that the source

has indeed returned to its safe position inside the camera.





CORDON

OFF

DISTANCECALCULA

TION



I NT E R NAT I O NA

L S Y S T E M OF U NI T S



DOSE LIMITS

Application Dose limitOccupational public

Whole body:

(effective dose)

20 mSv per year, averagedover defined period of 5years, with no more then 50mSv in a single year

1 mSv in a year,

Averaged over 5 years

Parts of the body

(equivalent body)

Lens of the eye

Skin *

Hands and feet*

150 mSv per year

500 mSv per year

500 mSv per year

15 mSv in a year

50 mSv in a year

* Averaged over areas of no more than any 1cm2 regardless of the area exposed



SIGNIFICANCE OF DIFFERENT LEVELS OF

RADIATION EPOSURE

DOSE SIGNIFICANCE

1-2 mSv/y 100-200mrem/y

Whole body Background radiation level at sea level(outdoors)

1 mSv/y 100 mrem/y Whole body Limit for non-radiation workers

5mSv/y 500 mrem/y Whole body Average occupational exposure

10 mGy 1 rad Whole body Risk of cancer mortality about 5 per 10000 exposed

20 mSv/y 2 rem/y Whole body Limit for radiation workers

150 mSv/y 15 rem/y Eye Limit for eye lens

500 mSv/y 50 rem/y Partial body Limit for skin and extremities

100 mGy 10 rad Whole body Detectable increase in chromosomeaberrations no detectable injury or

sickness ( contd…)





GOVERNMENT PUBLICATIONS ON RULES AND

REGULATION OF RADIATION SAFETY.

• The atomic energy Act, 1962 (33 of 1962), Government of India, Ministryof law, Government of India Press, New Delhi published in (1963).

• Radiation Protection Rules, 1971. The Gazette of India, New Delhi,October30,1971 1893, GSR 1601, Department of Atomic Energy, Bombay,

the 13th September, 1971.• The industrial radiography (Radiation Surveillance) Procedures, GSR 735,

Department of Atomic Energy, Bombay, the 30th January, 1980

• Safety code for transport of radioactive materials, 1986.

• Safety guide on enclosed radiography installations, 1986.

• Safety guide on open field industrial radiography,1987.• Safety guide for handling of radiation emergencies in industrial

radiography,1989.



STORAGE OF CAMERA



PIT-ROOM (For Camera storage)



Documents

Radio Graphic Inspection