8: Safe Working Procedures Flashcards
As per CNSC regulations, what is an exposure device used for?
Carrying out gamma radiography
As per CNSC regulations, what does an exposure device include?
Sealed source assembly, drive cable or drive tube and a source guide tube
Industrial radiography works with what range of radiation intensity (GBq)?
740 GBq - 3700 GBq
As per regulations, what does “operate” entail?
Coupling/uncoupling drive mechanism, locking/unlocking exposure device and ALL activities while source is not locked inside device in fully shielded position.
Work must be stopped immediately if EDO becomes aware of a reading reaching what amount?
2 mSv/h (200 mR/h)
What two types of exposure devices are there?
- Cable operated (cable drive)
2. Pneumatically operated (air drive)
What does a cable operated exposure device contain?
Source attached to pigtail which includes locking ball, Teleflax cable and a connector
How does the source get to the end of the guide tube in a cable operated exposure device?
With a drive cable and crank
How does the source get to the end of the guide tube in a pneumatically operated exposure device?
A pneumatic pump and drive tube
What does the GO NOGO gauge inspect?
Pigtail (female connector)
Which exposure device uses a double acting pump?
Pneumatically operated
What should you inspect the guide tube and drive tube for?
Kinks, cuts or breaks
What should you inspect the connectors for?
Damage, dirt and wear
What should you inspect the nozzle for?
Firmly in place on the guide tube
What does a pipeline exposure device contain?
Boomer plate with chains and spring loaded boomer handle to secure device in multiple positions
Who certifies ALL exposure devices used by CEDO’s in Radiography?
CNSC (Canadian Nuclear Safety Commission)
The final radiograph must contain 3 things…
- identification of item inspected
- location identifiers
- image quality indicators
What is clock tape?
Lead numbers sealed in transparent plastic tape that’s made in house
IQI (Image Quality Indicators) indicate which 2 things…
Quality and sensitivity
IQI’s must be made of what?
Same material as component inspected
What are the two types of IQI’s?
- Plaque/hole type
2 Wire type
How do you know which type of IQI to use?
Specified by codes and standards
A plaque type penetrameter is percentage of the component’s thickness?
2% (thousands of an inch)
You have a 1 inch thick section which is calculated by - 1 x 2% = 0.020”
What number penetrameter would you use?
20
You have material that is 8 inches thick, calculated by - 8 x 2% = 1.6”
What number penetrameter would you use?
16
How do you measure the sensitivity of an inspection?
The smallest visible hole
When using a plaque type penetrameter, where should it be placed in relation to area of concern?
BESIDES area of concern (instead of over it)
Describe a Wire Type IQI…
6-8 wires arranged in order of increasing diameter, between 2 sheets of clear, vinyl plastic
The smallest wire (#1) of the Wire Type IQI is equivalent to what ASTM hole type penetrameter?
7 ASTM hole type penetrameter
The largest wire (#6) of the Wire Type IQ is equivalent to what ASTM hole type penetrameter?
25 ASTM hole type penetrameter
Shooting a circumferential weld can be divided into 2 techniques, what are they?
Single/double wall exposure and single/double wall viewing
Describe single/double wall exposure:
Radiation travels through one or two wall thicknesses
Describe single/double wall viewing:
One or both walls of the tubular section are visible on radiograph
Contact exposure (DWE w/ SWV)
Source against specimen, shielded with collimator, only bottom part of weld visible on radiograph and mainly used on small pipes
Superimposed Exposure (DWE w/ DWV)
Source placed distance away from pipe and directly above, top and bottom weld will be superimposed on each other so markers need to be used to indicate difference
Used on small pipes - less than 3.5” in diameter
Elliptical Exposure (DWE w/ DWV)
Source distance away, slight angle to weld (about 15-30 degrees), cone of radiation “pushes” weld from perpendicular plane to horizontal position on film - top AND bottom weld visible on radiograph
Used on small pipes, less and 3.5” in diameter
Panoramic/Circumferential Exposure (SWE w/ SWV)
Whole weld inspection in ONE SHOT
Used for larger pipes/vessels
Bungee cords used as positioning fixtures need to be..
Strong enough to support weight of guide tube and collimator
Magnet stands are commonly used for what type of exposure?
Elliptical and superimposed
When elliptical exposure is not attainable (due to geometry or restricted accessibility), what is usually the next alternative?
Superimposed exposure
How many exposures are required to be taken for Superimposed?
3 required to obtain 100% coverage. First at 60 degrees, then 120 degrees..
What is a magnetic film holder used for?
Holding film or guide tubes in place during radiograph
What type of exposure device contains a pigtail?
Cable drive exposure device
Tool used with pneumatic device before connecting source guide tube and drive tube?
Dummy source
When is a push pull cable used?
During a pipeline radiographic operation using a pneumatically operated device
What equipment must an EDO have in possession before starting a radiographic operation?
Survey meter, DRD, PAD, TLD/OSD, emergency equipment
What is the emergency equipment required?
- Tongs - min 1.5 m
- Shielding material - will reduce intensity by factor of 100
- Tool to sever drive tube
Most IMPORTANT piece of EQUIPMENT you have for keeping yourself safe from radiation?
Survey meter
What is the range of approved survey meter?
20 microSv/h - 100 mSv/h
2 microR/h - 10 R/h
Accuracy required for a DRD?
+/- 20%
At what does rate must barriers be set up to prevent entry into where a radioactive source is being used?
0.1 mSv/h
10 mR/h
How do you determine the source-to-film distance?
In the codes and standards
What is a penetrameter used for?
Verify correct sensitivity and technique
2 types of commonly used DWV (double wall viewing) techniques?
Superimposed and elliptical
What type of radiation source is centered inside of a welded pipe?
Panoramic exposure
3 types of source positioning fixtures used for radiography?
- Bungee cords/straps
- Magnetic stand
- Magnetic film holder/paddle magnets
DOSE RATE limit for a source in shielded position?
2 mSv/h (200 mR/h) at any point of surface
DOSE RATE limit for barriers/signs?
Anywhere dose rate will be more than 0.1 mSv/h (10mR/h)
DOSE RATE limits of radiation signs?
Boundary of room where person could be exposed to 25 microSv/h (2.5 mR/h) or higher
DOSE RATE limit for a PAD?
Reaches or exceeds 5 mSv/h (500 mR/h)
What is the ACCUMULATED dose limit for a non-NEW per week and year?
- 1 mSv (10 mrem)/week
0. 5 mSv (50 mrem)/year
Max annual dose for a pregnant NEW?
4 mSv (400 mrem)
Max annual dose for a non-NEW?
1 mSv (100 mrem)
Max annual dose for a NEW?
50 mSv (5 rem)
When do you verify the boundaries around your operation?
During initial exposure
What is the metal tag on the exposure device made out of?
Brass
One of the most important checks that a CEDO should make sure to perform correctly?
GO NOGO/gauge check
What is a leak test?
Taking a wipe sample and measuring the radioactivity collected
As per NSRDR, leak tests must be conducted with instrument able to detect how much?
200 Bq
How often should a leak test be performed?
Every 12 month or whenever capsule assembly is changed
Who deals with the transport of all dangerous goods?
Transport Canada
Which regulations need to be considered when transporting in Canada?
CNSC’s regulations: Packaging and Transport of Nuclear Substances (PTNS) regulations
Who prepares a consignment for transport?
Consignor
Who receives the consignment?
Consignee
What is a Competent Authority?
National/international regulatory body/authority designated to act of behalf of a country in all matters related to transport of radioactive material
What is assigned to a Class 7?
Any substance with a specific activity greater than 70 kBq/kg
(all radioisotopes used in industrial radiography)
What are the 2 MAIN types of packages?
Type A (activity under x amount) and B (when activity exceeds x amount)
What are the shipping names and UN numbers used for?
To identify nature and characteristics of material being shipped (internationally recognized)
What does the Transport Index (TI) do?
Provides control over radiation exposure to transport workers and to the public
How do you determine TI?
Measure max radiation (mSv/h) at a distance from 1 meter from external surface of package - multiply number by 100 - round to first decimal
How often should leak tests be performed?
Every year (2 years for empty device) or when changed
3 things needed to perform leak tests?
Survey meter, sealable plastic bags, swab
Once leak test is completed, what should be done with samples?
Samples put in a sealed, labelled container, placed in locked, approved shipping container and sent by COURIER to leak testing facility
When receiving new source, what are 2 basic precautions that must be taken prior to performing source change?
Inspect package for damage and use survey meter to determine if there are leaks
Exposure/Dose control program is sometimes referred to as?
ALARA
What if CEDO meets or exceeds the third action level or “investigation” level of company’s manual?
CEDO will be informed they’ve met/exceeded level, audit would be performed to ensure employee is taking proper precautions, investigate to make sure a specific incident didn’t cause it, employee will take written test, their job will be shadowed by safe employee for 3+ shifts
