National Sealed Source Registry and Sealed Source Tracking System Report for 2017

Sealed sources are radioactive nuclear substances encased in a sealed capsule or in a cover to which the substance is bonded. They can be used for a variety of activities, including medical, industrial, commercial, and academic and research applications. An inventory of sealed sources within Canada is housed in the National Sealed Source Registry (NSSR), which was established in 2006 to conform to the International Atomic Energy Agency (IAEA) Code of Conduct on the Safety and Security of Radioactive Sources. The NSSR is used to maintain an accurate and secure inventory of sealed sources in Canada, with a particular focus on those classified as high risk.

The Sealed Source Tracking System (SSTS) is a secure information-management system used in conjunction with the NSSR to track new and existing high-risk sources within Canada. Source transfers done online through the SSTS update and populate the NSSR so that the information is as current as the licence reporting allows (e.g., reporting within two days of receipt and seven days in advance of any transfer). The CNSC places particular emphasis on capturing data on high risk sources, with the NSSR housing detailed information such as the serial number, isotope, activity, and current location. Information on moderate- and low-risk sources is updated annually using the inventory data included in licensee's annual compliance reports (ACRs) and validated by the CNSC for accuracy and consistency.

Categories of sealed sources

Sealed sources are classified by the IAEA into five different categories:

Category 1

Very high risk

Category 2

High risk
(or risk-significant)

Category 3

Moderate risk

Category 4

Low risk

Category 5

Very low risk

For more information on how sealed sources are categorized, consult the CNSC website.

By the end of 2017, the NSSR contained information on 112,543 radioactive sealed sources in Canada. The SSTS actively tracks Category 1 and 2 sources. In 2017, 6,260 Category 1 and 56,970 Category 2 sources were tracked. The remaining 49,313 in the NSSR were Category 3, 4 or 5, which are not subject to mandatory tracking for every movement.

Sealed Source Inventory Trends

The number of sources located in Canada increases every year, mainly due to source manufacturers accepting returned sources for recycling, reuse and long-term storage. Figure 1 shows the total number of sealed sources, as well as the number of sealed sources in each category, that were accounted for in Canada on December 31, 2017. In 2017, there was a 9% increase in the number of high-risk sources compared to 2016, with the majority of the increase coming from the production of Category 2 sources. The increase in Category 3 sealed sources was primarily attributed to the return of sealed sources no longer suitable for use in prescribed equipment and to the decay of Category 2 sources held by licensees.

Figure 1. Breakdown of sealed sources in Canada on December 31, 2017
2013 2014 2015 2016 2017
Total sources 66139 79077 92831 100996 112543
Category 1 3993 5734 6748 6273 6260
Category 2 32466 39167 45673 51501 56970
Category 3 24242 28701 34899 37675 43784
Category 4 484 224 200 293 258
Category 5 4954 5251 5311 5254 5271

Performance measures and verification

To gauge the effectiveness of the SSTS and verify the accuracy of the data in the system, CNSC inspectors physically cross-reference SSTS data against licensees’ actual inventory of sealed sources. Routine CNSC compliance inspections include requirements to verify sealed source tracking information. Inconsistencies are immediately addressed to ensure accuracy in the data. Typically administrative in nature, these inconsistencies may include errors in source serial numbers and reference dates, or the use of non-standard terminology when identifying sealed source assemblies.

In 2017, 133 inspections were conducted. Of these, 130 (98%) were found to be compliant and 3 (2%) were found to be non-compliant. The licensees that were initially found to be non-compliant have adequately addressed the issues identified during their inspections. The non-compliances included licensees not providing notification of SSTS transactions within the required time frame as per their licence conditions, and not up-to-date tracking information.

For more information on inspection results of Canadian licensees using nuclear substances relative to doses to workers, radiation protection, operating performance and sealed source security, refer to the annual Regulatory Oversight Report on the Use of Nuclear Substances in Canada.

Event mitigation

Licensees must immediately report lost or stolen nuclear substances to the CNSC and must also submit descriptions of any actions taken or proposed to recover missing nuclear substances. The CNSC investigates every such event and informs local, national, and international stakeholders who may assist with recovery. A list of events involving sealed sources can be found in the Lost or Stolen Sealed Sources and Radiation Devices Report.

The International Nuclear and Radiation Events Scale (INES) is a tool for communicating the safety significance of nuclear and radiological events to technical communities and the public. Every event reported from the commercial, academic and research, industrial, and medical sectors is classified in accordance with the INES, based on its safety significance rating. Of the following events, only one event was rated at INES Level 1 (anomaly). All other events were rated at INES Level 0, which are considered below scale and have no safety significance.

Figure 2. INES rating descriptions


A total of 19 sealed sources were involved in 11 events in 2017 (15 lost sources, 2 stolen sources and 2 recovered sources). These sources were classified as Category 4 or 5, which are low- to very-low risk sources.

Figure 3. Number of reported events involving, lost, stolen and found sealed sources from 2013 to 2017
2013 2014 2015 2016 2017
Lost/stolen 14 13 16 12 10
Found 3 3 1 3 1

Notes for figure 3:

  • No events involved Category 1 sources.
  • No events involved Category 2 sources.
  • No events involved Category 3 sources.
  • Three events involved a total of six Category 4 sources. These are considered low-risk sources and are unlikely to be dangerous. All events involved portable gauges that contained two sealed sources.
    1. Lost Category 4 sources: A portable gauge fell off the back of a truck during transportation. A search was conducted and a police report was filed. Three days later, a member of the public found the gauge and notified the police. The gauge was recovered in its transport box with no visible signs of damage, and the radiation levels were found to be within normal limits. The licensee implemented corrective actions to prevent future recurrences. This event is now closed.
    2. Stolen Category 4 sources: A portable gauge was stolen from the back of a locked vehicle. Local authorities were contacted to report the theft and to release a public notification. The portable gauge has not been recovered and this event remains under investigation. Based on the number of nuclear substances involved and the type of event reported, theft, this event was ranked as an INES Level 1 (anomaly). However, because of the low-risk nature of the sources involved, this event does not pose a significant risk to the public or the environment.
    3. Found Category 4 source: A portable gauge was found on the doorstep of a member of the public who was previously a CNSC licensee. The CNSC issued a contract with a servicing licensee for the pickup, storage and disposal of the gauge. The servicing licensee has confirmed that all services have been rendered, and this event is now closed.
  • Eight events involved Category 5 sources. There were 8 events involving a total of 13 Category 5 sealed sources. All events described below involve lost or missing sealed sources. These are considered very low risk and pose no danger because of their low activities, short half-lives or radiological nature.
    1. In three cases, three sealed sources (one source in each case) used as radioactive seeds were not recovered following surgery. Licensees made efforts to find the seeds, but the searches were unsuccessful. Two licensees have implemented corrective actions to prevent future recurrences. The third incident was determined to be an isolated event and so no further actions were required. Due to the negligible risk to the public and the environment, these events are considered closed.
    2. One sealed source used for teaching purposes was reported missing by a licensee. There is no reason to believe that the source was stolen; it was likely misplaced. The licensee implemented corrective actions to prevent recurrences. Due to the negligible risk to the public and the environment, this event is considered closed.
    3. In one case, a calibration source was misrouted while being delivered to a licensee. The licensee was unaware that the source was being delivered, and attempts to find the source have been unsuccessful. The licensee implemented corrective actions to prevent future recurrences. Due to the negligible risk to the public and the environment, this event is considered closed.
    4. In one case, a licensee reported five sealed sources as missing while performing an inventory check. It is believed that the sources were not stolen but misplaced or lost. The licensee implemented corrective actions to prevent future recurrences. Due to the negligible risk to the public and the environment, this event is considered closed.
    5. In one event, two Category 5 sources were discovered missing from a licensee’s inventory but were later recovered. The licensee’s internal permit to possess sealed sources was temporarily suspended and corrective actions were implemented to prevent recurrences. This event is closed.
    6. In one event, a calibration source was noted to be missing. The licensee believes it may have been inadvertently returned to the supplier along with other isotopes. The supplier was notified, but could not confirm the location of the source. The licensee implemented corrective actions to prevent recurrences. Due to the negligible risk to the public and the environment, this event is considered closed.

Transaction statistics

The NSSR is populated by licensees reporting their transactions via the online SSTS interface or by other means (such as fax, email or regular mail). Figures 3, 4 and 5 show transactions entered in the SSTS in 2017, statistics for import and export of sealed sources, and the percentage of online SSTS transactions from 2013 to 2017, respectively.

Figure 4. SSTS transactions in 2017
Import Export Exchange Create Change Cancel Transfer Receive
Transactions 14858 18491 3484 16514 9975 255 5864 5735
  • Create: Creation of a new source manufactured in Canada
  • Exchange: Replacement of one source for another in a radiation device or prescribed equipment at a licensed location
  • Export: Transfer of a sealed source from Canada to a foreign destination
  • Import: Transfer of a sealed source to Canada from a foreign destination
  • Receive: Reception of sources by licensees at licensed locations
  • Transfer: Transfer of sources within Canada between licensees and licensed locations
  • Change: Transaction date change or correction
  • Cancel: Cancellation of transaction due to unforeseen circumstances (e.g., export and shipment cancellations, delayed transfers)

A total of 75,176 sealed source transactions were recorded in the SSTS in 2017, which represents a 15% increase over the number of transactions recorded in 2016.

Figure 5. Number of sealed source imports and exports from 2013 to 2017
2013 2014 2015 2016 2017
Number of sources imported into Canada 12218 14307 14924 11577 14858
Number of sources exported from Canada 14171 19047 17029 17311 18491

Users of nuclear substances in Canada routinely import and export sealed sources in accordance with their licences. There was a 7% increase in the number of exports, and a 28% increase in the number of imports in 2017 over 2016.

Figure 6. Percentage of SSTS transactions completed online from 2013 to 2017
2013 2014 2015 2016 2017
Percentage of Web transactions relative to number of transactions 88 94 93 95 94

In 2017, 94% of all transactions were done via the SSTS Web portal, a proportion that has remained steady since 2014.

Licensees’ continued use of the SSTS indicate that its implementation, as well as that of the NSSR, has been effective, and that Canada is maintaining its commitment to the Code of Conduct on the Safety and Security of Radioactive Sources.

Additional resources

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