Overview of Industrial Radiography Sources and Accidents
IAEA Day 5 – Lecture 3 International Atomic Energy Agency Objectives
To understand:-
• the applications of industrial radiography
• the potential for accidents during the use of industrial radiography radiation sources.
IAEA 2 Contents
• The beneficial uses of ionizing radiation as used in industrial radiography practices • The potential harmful effects due to the lack of and/or effectiveness of an adequate and appropriate radiation safety program • The consequences of radiological accidents
IAEA 3 What is Industrial Radiography?
Industrial radiography is:- • a process of non-destructive testing for examining the quality of a component or product;
• most often utilized for quality control of metal fabrication for the oil/gas industry; • also used to test a range of other products.
IAEA 4 Imaging Principles
IAEA 5 Overview of Industrial Radiography Equipment
Knowledge is required of:- • the devices that use ionizing radiation from radiation sources (radioactive substances and x-ray devices) for industrial radiography;
• the types of radionuclides and activities used; • work environments, that may range from clean laboratories to fabrication workshops and mining environments; • equipment design and the work procedures that are essential to protect both the radiation worker and the public.
IAEA 6 History
• Roentgen discovers x-rays in 1895 • Early x-ray tubes were unreliable • Vacuum x-ray tube and heated filament (Coolidge-1913) • 200kVp achieved in 1922
IAEA 7 History (cont)
• 1930s and 1940s 226Ra was used. • 60Co and 192Ir after World War II
IAEA 8 Types of Industrial Radiography Equipment
Common Uncommon •gamma source projectors •betatron •directional x-ray •linear accelerator •panoramic x-ray •neutron radiography •x-ray crawlers •torch devices •gamma crawlers •fluoroscopy •crawler control sources
IAEA 9 X-ray Equipment
Has three main components:- • x-ray tube assembly; • x-ray control panel; • high tension (HT) cables.
IAEA 10 Betatron
Special Considerations • survey meters with appropriate response • operator training • shielding
IAEA 11 Gamma crawler equipment
Special applications • on-shore pipelines • off-shore pipelines (on a barge) • remotely controlled with a separate ‘control’ source, typically 137Cs.
IAEA 12 Radioactive Sources and some properties
Half Value Layer (cms) Tenth Value Layer (cms) Isotope Lead Iron Concrete Lead Iron Concrete 192Ir 0.6 1.3 4.6 2.0 4.3 14.7 60Co 1.2 2.0 6.6 4.0 6.9 20.6 169Yb 0.26 0.95 0.29 1.8 75Se 0.11 0.8 3.0 0.475 2.75 9.0
IAEA Projector-type radiography equipment
IAEA Source containers
Source containers must comply with recognized standards to ensure that exposures to users and the public are kept As Low As Reasonable Achievable.
The shielding of source containers must remain intact following any credible accident or incident. The shielding of this container (right) remained intact following a severe fire at the licensed premises.
IAEA 15 Fluoroscopy
IAEA 16 Industrial Radiography Accidents
• 48 industrial radiography accidents1 were reported to the US Nuclear Regulatory Commission between 1971 and1980. • Severe injuries and a number of deaths have since been reported and investigated.
1involving doses greater than 50 mGy to the whole body or 750 mGy to a part of the body. (Ref: NUREG/BR-0024). Many accidents may go unreported because those responsible fear the legal consequences.
IAEA 17 Industrial Radiography Accidents (cont)
•IAEA Safety Report Lessons Learned from Accidents in Industrial Radiography. Series No.7:- • 43 cases; 9 involving the public or other non-radiation workers.
IAEA Industrial Radiography Accidents (cont)
Severe injuries to a non-radiation Day 15 worker resulting from the radiography worker failing to use a survey meter to confirm the source had been returned to the shielded container.
• 185 GBq 192Ir in shirt pocket for 90 minutes • estimated skin dose of 30 Gy; whole body as 2-5 Gy
IAEA 19 Industrial Radiography Accidents (cont)
Poor source security leading to severe injuries and death
137Cs industrial radiography source; Argentina 1968
IAEA 20 Industrial Radiography Accidents (cont)
Poor source security leading to severe injuries and death Doses • 17000 Gy (localized) • 1 - 8 Gy (internal organs) • 0.6 Gy (head)
137Cs industrial radiography source; Argentina 1968
IAEA 21 Industrial Radiography Accidents (cont)
Yanango, Peru 1999
1.37 TBq 192Ir. 2 days after accident; blister on upper thigh.
IAEA 22 Industrial Radiography Accidents (cont)
Source not properly secured. Loss not apparent for 6 hours.
Skin dose at 1cm estimated at 10 kGy; right leg amputated. The worker’s wife and two children were also exposed.
IAEA 23 Consequences of Accidents
• Severe deterministic effects death, loss of limbs, erythema
• Increased stochastic risk
fatal cancer • Environmental contamination • Social & economic consequences
IAEA 24 Causes of Accidents
•Causes identified as contributing to accidents:
• Lack of or inadequate regulatory framework
authorization
inspection
enforcement • Lack of or inadequate safety culture
management
quality control
training and qualifications of workers
IAEA 25 Causes of Accidents (cont)
Regulatory control Failure to use lacking or survey meter inadequate
Equipment ACCIDENT Inadequate or failure lack of training
Safety procedures Lack of safety not followed program
IAEA 26 Causes of Accidents (cont)
Regulatory control lacking or inadequate
ACCIDENT The Regulatory Authority has inadequate:- • authorization processes; • field inspections; • inspection follow up.
IAEA 27 Causes of Accidents (cont)
ACCIDENT Inadequate or lack of training
Lack of training (and ongoing training) results in:- • unqualified and poorly instructed workers; • poor or no understanding of emergency procedures
IAEA 28 Causes of Accidents (cont)
ACCIDENT
No safety program • inadequate management Lack of safety • lack of safety culture program
IAEA 29 Causes of Accidents (cont)
Safety procedures not followed indicates:- • lack of safety culture • inadequate supervision • lack of training ACCIDENT
Safety procedures not followed IAEA 30 Causes of Accidents (cont)
Equipment ACCIDENT failure
Equipment failure indicates:- • lack of manufacturer’s recommended maintenance; • poor use of equipment; • equipment being used beyond design limits
IAEA 31 Causes of Accidents (cont)
Failure to use survey meter
Failure to use survey meter indicates- ACCIDENT • insufficient and/or non-functioning meters; • inadequate user safety training; • hurrying to complete the work (employer pressure); • lack of safety culture.
IAEA 32 Safe use of Radiation Sources
Radiation Sources: • are widely used; • provide substantial benefits; but • can cause harmful effects (injury or death).
Safe operation requires: • training; • maintenance; } SAFETY CULTURE • control.
IAEA 33 Safe use of Radiation Sources (cont)
the RISKS BENEFITS should outweigh
IAEA 34 References
• IAEA, International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources, Safety Series No. 115, Vienna (1996).
• IAEA, Organization and Implementation of a National Regulatory Infrastructure Governing Protection against Ionizing Radiation and the Safety of Radiation Sources, IAEA-TECDOC-1067, Vienna (1999).
• IAEA, Lessons learned from accidents in industrial radiography, (reports in) Safety Reports Series.
• IAEA, Accident reports.
IAEA 35 Exercise
•Consider the following industrial radiography equipment; portable x-ray; fixed x-ray; fixed gamma; portable gamma. • Which has the greatest potential to cause serious harm to the user and to the public?
• Why?
IAEA 36