1. Categorization and Field Identification of Sealed Radioactive Sources
Regional Training Course “Orphan Source Search Training”
TC Regional Project RAS/9/062 and RAS/9/085
Philippine Nuclear Research Institute (PNRI)
Quezon City, Philippines
October 2016

2. Introduction By the end of this module students will be able to:
Categorize sealed radioactive sources;
Identify common sources and devices by appearance

3. Overview
Categorization of radioactive sources is based upon radioisotope and radioactivity or practice
Typical practices in each category
Examples of common sources and devices in each category

4. Categorization of Radioactive Sources Safety Standards Series: RS-G-1
To provide an internationally harmonized basis for risk-informed decision making on radioactive sealed sources
Scope:
Includes radioactive sources used in industry, medicine, agriculture, research and education
Focuses on sealed radioactive sources
Excludes:
X-ray machines
Nuclear materials as defined in the Convention on the Physical Protection of Nuclear Materials

5. Basis for Categorization of Radioactive Sources
Categorization is based on the potential to cause death or severe injuries
Considers radioisotope and radioactivity (A)
A dangerous source is one with an activity (≥D) that could, if not under control, give rise to an exposure sufficient to cause an effect that is fatal or life threatening or results in a permanent injury that decreases the quality of life A D

6. Categorization of Radioactive Sources
Category
Activity Ratio A/D
Practice 1
A/D ≥ 1000
RTG’s; Irradiators;
Teletherapy; Gamma Knife 2
1000>A/D≥10
Industrial gamma radiography
Brachytherapy (High and Medium Dose Rate) 3
10>A/D≥ 1
Fixed industrial gauges with high activity sources (level, dredge, conveyor gauges etc.)
Well logging gauges 4
1>A/D≥ 0.01
Brachytherapy (LDR except eye plaques & permanent implants)
Industrial gauges with lower activity sources (e.g. portable moisture/density gauges)
Bone densitometers; Static eliminators 5
0.01>A/D
and
A>Exempt
Brachytherapy (eye pl. & perm implants);
XRF devices; Electron capture devices; Mossbauer sources: PET check sources
Increasing Risk

7. Some D values of interest
Radionuclide
D (TBq)
D (Ci)
Am-241
0.06 2
Co-60
0.03
0.8
Cs-137
0.1 3
Ir-192
0.08
Sr-90/Y-90 1 30

8. A little more about the D Value..
A dangerous source is one that could give rise to an exposure sufficient to cause a severe deterministic effect (SDE)
(A deterministic effect is one for which a threshold level of dose exists and above it, severity increases with dose)
A SDE is fatal or life threatening or causes permanent injury
D values are calculated from the quantity of RAM that could give rise to a SDE for given scenarios and dose criteria

9. D Value: Scenarios and Dose Criteria
Scenarios include dispersion due to malevolent acts
Unshielded source in hand for 1 hr or pocket for 10 hrs or room for days to weeks
Dispersal of source by fire or explosion or human action
Dose criteria
1 Gy to bone marrow or 6 Gy to lung in 2 days (low LET)
25 Gy to the lung from inhalation of high LET radiation in one year
5 Gy to the thyroid in 2 days
For a source contacting tissue, 25 Gy at a depth of 2 cm
For source too big to be carried, a dose of 1 Gy to bone marrow in 100 hrs at a distance of 1 m
Page of RS-G-1.9

10. Categorization of Radioactive Sources
Category
Activity Ratio A/D
Practice 1
A/D ≥ 1000
RTG’s; Irradiators;
Teletherapy; Gamma Knife 2
1000>A/D≥10
Industrial gamma radiography
Brachytherapy (High and Medium Dose Rate) 3
10>A/D≥ 1
Fixed industrial gauges with high activity sources (level, dredge, conveyor gauges etc.)
Well logging gauges 4
1>A/D≥ 0.01
Brachytherapy (LDR except eye plaques & permanent implants)
Industrial gauges with lower activity sources (e.g. portable moisture/density gauges)
Bone densitometers; Static eliminators 5
0.01>A/D
and
A>Exempt
Brachytherapy (eye pl. & perm implants);
XRF devices; Electron capture devices; Mossbauer sources: PET check sources
Increasing Risk

11. What the categories mean:
Category
Plain language description of risk is being close to an individual source
Risk in the event at the radioactive material is disbursed by fire or explosion 1
Extremely dangerous to the person
Could permanently injure or be life threatening to persons in the immediate vicinity 2
Very dangerous to the person
Little or no risk of health effects beyond a hundred meters 3
Dangerous to the person
Little or no risk to persons a few meters away 4
Unlikely to be dangerous to the person
Could not permanently injure persons 5
Most unlikely to be dangerous to the person
Could not permanently injure anyone
Source, Table 3 of RS-G-1.9

12. Category 1 A/D ≥ 1000 Applications:
Radioisotopic thermoelectric generators (RTG’s)
Industrial Irradiators (e.g. sterilizers and food irradiators)
Teletherapy
Fixed multi-beam teletherapy (gamma-knife)
Seed irradiators

13. Radioisotope Thermoelectric Generators (RTGs)
Devices that use sources to generate heat that is converted to electricity to power various devices, often in remote locations
90Sr Activity ranges from:
90Sr 3.3 – 25 PBq (9,000 – 680,000 Ci)
Lighthouses, military uses
Radioisotope heaters and
Extraterrestrial RTGs - Galileo space craft Galileo was an American unmanned spacecraft that studied the planet Jupiter and its moons, as well as several other Solar System bodies. Named after the astronomer Galileo Galilei, it consisted of an orbiter and entry probe.
Each GPHS-RTG, mounted on a 5-meter long boom, carried 7.8 kilograms (17 pounds) of 238Pu.[11] Each RTG contained 18 separate heat source modules, and each module encased four pellets of plutonium dioxide, a ceramic material resistant to fracturing. The modules were designed to survive a range of hypothetical accidents: launch vehicle explosion or fire, re-entry into the atmosphere followed by land or water impact, and post-impact situations. An outer covering of graphite provided protection against the structural, thermal, and eroding environments of a potential re-entry. Additional graphite components provided impact protection, while iridium cladding of the fuel cells provided post-impact containment. The RTGs produced about 570 watts at launch. The power output initially decreased at the rate of 0.6 watts per month and was 493 watts when Galileo arrived at Jupiter.
A diagram of Galileo's main components.
As the launch of Galileo neared, anti-nuclear groups, concerned over what they perceived as an unacceptable risk to the public's safety from Galileo's RTGs, sought a court injunction prohibiting Galileo's launch. RTGs had been used for years in planetary exploration without mishap: the Lincoln Experimental Satellites 8/9, launched by the U.S. Department of Defense, had 7% more plutonium on board than Galileo, and the two Voyager spacecraft each carried 80% as much plutonium as Galileo did. However, activists remembered the messy crash of the Soviet Union's nuclear-powered Cosmos 954 satellite in Canada in 1978

14. Industrial Irradiators
Typically 137Cs or 60Co Activity ranges:190 TBq-560 PBq
(5,000–15,000,000 Ci)

15. Seed Irradiators 137Cs in 100’s of TBq (1000’s Ci) quantities

16. Blood Irradiators Used to sterilize blood
Found in medical or research applications
Typically 60Co, 137Cs, 170Tm
Activity ranges from:
60Co 56 TBq – 1.9 PBq (1,500 – 50,000Ci)
137Cs 37–440 TBq (1,000–12,000Ci)

17. Field Identification: Irradiators

18. Teletherapy Used for treating tumors Found in medical clinics
Typically contains 60Co or 137Cs
Activity ranges from:
60Co 37–560 TBq (1000–1,5000 Ci)
137Cs 19–56 TBq (500–1,500 Ci)

19. Abandoned 60Co Teletherapy Device

20. Teletherapy Source

21. Category 2 1000>A/D≥10 Applications: Industrial gamma radiography
High and medium dose rate brachytherapy
Instrument calibration

22. Industrial Radiography
Used to take pictures of dense objects to check for defects
Portable
192Ir ,60Co,75Se,169Yb,170Tm
Typical activities are
0.19–7.4 TBq (5–200 Ci)

23. Field Identification: Radiography

24. Field Identification: Radiography

25. Brachytherapy (HDR/MDR)
Sources placed inside or near a tumor to deliver a large dose to the tumor tissue
Radionuclide and activity depends varies based on type of tumor:
137Cs • 198Au
60Co • 125I
192Ir • 252Cf

26. Instrument Calibration Sources

27. Category 3 10>A/D≥ 1 Applications:
Fixed industrial gauges with high activity sources
level gauges
dredger gauges
conveyor gauges containing large sources
spinning pipe gauges
Well logging gauges

28. Industrial Level Gauges

29. Industrial Gauges Common 137Cs 110 GBq (3 Ci) Contact dose rate
up to 75 Sv/h
industrial gauges

30. Field Identification: Level/Density/Flow Gauges

31. Well logging 241Am/Be 37 GBq (1 Ci) Neutron and gamma dose rate
10 cm from tool
up to 2.1 mSv/h

32. Oil Well Logging Sources

33. Pacemaker
Pu-238 (87.7 years)

34. Category 4 1>A/D≥ 0.01 Applications:
Low dose rate brachytherapy (except 90Sr eye plaques and permanent implant sources)
Industrial gauges that incorporate low activity sources
Thickness/fill-level gauges
Portable gauges (e.g., moisture/density gauges)
Bone densitometers
Static eliminators
High level lightning rod arrestors (154/152Eu)

35. Beta thickness gauges 147Pm 3.7 GBq (0.1 Ci) Shutter open (beta)
Between guide plates
up to 10 Sv/h

36. Field Identification: Thickness Gauges

37. Thickness and Density Gauge

38. Source capsules
Beta emitter
Low energy gamma

39. Neutron gauges 241Am/Be ~ 1.85 GBq (50 mCi)
Neutron and gamma dose rate
Contact dose rate
up to 30 Sv/h

40. Moisture Density Gauge
Unit can have two sources:
Gamma 137Cs or 226Ra
Neutron 241AmBe or 252Cf
Activity ranges:
137Cs: 300–410 MBq
(8 – 11 mCi)
241AmBe: 370–3700 MBq (10–100 mCi)
226Ra: 74–150 MBq
(2–4 mCi)
252Cf: 1.1–2.6 MBq
(30–70 Ci)

41. Field Identification: Moisture/Density Gauges

42. Field Identification: Hydrology
Information available on source from the devices shown?
Information on device
can be used with IAEA Source Catalogue, US NRC Sealed Source and Device Registry – or communicated back to more knowledgeable organization to assist in identifying individual source data

43. Static Electricity Eliminators

44. High Level Lightning Rod Arrestors
154/152Eu 2-15 GBq ( mCi)
60Co 18 GBq (500mCi)

45. Category 5 0.01>A/D and A>Exempt Applications:
Low dose-rate brachytherapy eye plaques and permanent implant sources
X-ray fluorescence devices
Electron capture devices
Mossbauer spectrometry
PET check sources
Low level lightning rod arrestors

46. Low Activity Sealed SourcesX X

47. Field Identification: X-Ray Fluorescence Devices

48. Low Level Lightning Rod Arrestors
Trade Mark: Nuclear Ibérica
Model: Minocptor
Sources: Am-241
Trade Mark: Nuclear Ibérica
Model: Ionocaptor
Sources: Am-241
Trade Mark: Helitita
Source: Am-241
Typically
MBq (1-10 mCi)
Tests done in the 1960s with millicurie sized radioactive sources including thoroim and in particular, radium 226 did not indicate any advantage in preventing lightning strikes
However in the 1980s again using small radium sources of approximately 0.72 µci seem to indicate some benefit over a simple metal Franklin style lightning rod.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 30, NO. 5, SEPTEMBER / OCTOBER
Lightning Protection Systems: Advantages Disadvantages Donald W. Zipse, Fellow, IEEE
Trade Mark: Energía Fría
Sources: C-14
Trade Mark: : Fair Raythor
Sources: Am-241 or Ra-226

49. Tritium Exit Signs

50. Field Characterization: Source Markings

51. Field Characterization: Device Labels
Very useful information – especially when coupled with type of device or manufacturer sources are in

52. International Catalogue of Sealed Radioactive Sources and Devices

53. Objectives of the Catalogue
Two major objectives:
To provide vital information for a wide range of individuals and organizations on industrially manufactured radioactive sources and devices
To facilitate identification of design specifications based on limited information from orphan sources and devices to allow safe handling of these items

54. Catalogue entries 10 000 sources, 10 000 devices, 1300 suppliers

55. Example of Use: “Metal object” in scrap yard.
“The length of the cylinder was approximately 20 cm and the diameter 5 cm. The diameter of the screw was 1 cm.”
Cyrillic: IBN-8-1
Cyrillic: Year 1986

56. Source could fit behind “screw”

57. Characterization: Manufacturers’ Documentation

58. Characterization: Identify through Measurement
Last resort:
Dose rate
Type of radiation
Isotope identifier
Quantification?
Hand held isotope identification instrumentation typically limited when spectrum is busy or high degrees of resolution are required
High occurrences of mis-identification
Training and qualification on instrumentation a key to success

59. Summary
Radioactive sources come in a large variety of isotopes, activities and appearances
The more hazardous sources are in Categories 1, 2 and 3
There are a number of ways of identifying radioactive sources including: warning signs, labels, measurements and catalogues

60. More Information on Source Identification
IAEA International Catalogue of Sealed Radioactive Sources can help identify a source:
US DOE Off-Site Source Recovery Project, information and contact information at:
IAEA Nuclear Security Series No. 5, Identification of Radioactive Sources and Devices, IAEA, Vienna, 2007
IAEA Web Site: