Leak Testing

CNSC requires that all sealed sources that are not exempt for licensing and that contain 50 MBq or greater of radioactive material, be monitored to assess the integrity of the material housing the source.By definition a sealed source provides a level of assurance that the radioactive material can not escape and result in contamination or an inadvertent exposure. Unfortunately due to age, use or damage, the integrity of the housing material can be compromised resulting in a potential serious situation. In evaluating the risk verses the probability of an incident CNSC has set a graduated leak test frequency schedule that takes into consideration whether the sources are in storage, incorporated into devices, or in use.


The frequency of leak testing is as follows:

  • immediately after an event which may have resulted in the sealed source or shielding being damaged;
  • immediately before using a source that had been in storage for a period of 12 consecutive months or greater;
  • every 6 months for sealed sources in use and not incorporated into a device;
  • every 12 months for sealed sources incorporated into a device;
  • every 24 months when a source is in storage
It is the responsibility of the permit holder to ensure all the sealed sources in their possession that require leak testing are monitored at the designated frequency. CNSC requires that the leak testing procedures be approved by Commission, the interval between sampling and measuring should be as short as possible and must be completed within 10 days of the each other and finally both procedures and the results recorded on dedicated forms (below). Depending upon your faculty and laboratory it may be possible to coordinate the leak test sampling and measuring with others permit holders to allow for a more effective and efficient process. In some circumstances this may not be possible due to the location of the laboratory, use scheduling of the source, or personal preference. As a result individual permit holders may elect to leak test their own sources independently. Regardless of the process, ORM must receive a copy of both the sampling and measuring certificate for addition to the permit holder's file. In addition, the permit holder must retain these records for 3 years. Additional information may be obtained by contacting ORM.


Should a source be found to be leaking 200 Bq or greater, the following action must be taken:

  • discontinue the use of the sealed source or sealed source incorporated into a device,
  • minimize the risk of contamination,
  • immediately contact ORM, so that the appropriate reporting of the incident can occur to CNSC, and
  • in consultation with ORM determine the remedial actions to be undertaken to minimize exposure to the radiation and to decontaminate where necessary
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