Nuclear substance safety - Canadian Nuclear Association

Nuclear substance safety

The Canadian Nuclear Safety Commission (CNSC) issues licences to organizations that plan to work with nuclear substances or in nuclear facilities; these licences require that the organizations comply with Canada’s nuclear laws and regulations – and can be revoked at any time that the organization does not.

To verify compliance, in 2016, the CNSC conducted 1,452 inspections of organizations involved in four broad areas of activity:

  • medical – use of nuclear energy and nuclear substances for medical diagnostics and therapies, principally for heart diseases and cancer;
  • industrial – use of nuclear substances in fixed and portable gauges for activities such as civil engineering, industrial radiography, and oil-well logging;
  • academia and research – use of nuclear substances for biological and biomedical research, and with particle accelerators and research irradiators; and
  • commercial – production and sale of devices and equipment containing nuclear substances, such as smoke detectors, self-lighting exit signs, and security-screening equipment.

The CNSC evaluates licence compliance on five performance-measurement categories: radiation exposure, operating performance, radiation protection, sealed-source tracking, and reported events.

Radiation exposure

In 2016, CNSC sampled 1,584 licence holders, representing 62,013 workers, to ensure that workers were not exposed to unsafe levels of radiation.


Dosimeter. Source: Cameco.

Of the 62,013 workers, 22,606 qualified as nuclear energy workers: those who worked with nuclear substances or at a nuclear facility. These workers carry devices called “dosimeters” that measure the accumulated exposure of the worker to radiation over a set period (usually one year).

All but one of the workers received radiation doses well below the regulatory limit of 500 millisieverts (mSv) per year for nuclear energy workers. The one exception was an extremity dose of 1,100 mSv from contamination while administering medical isotopes.

None of the nuclear energy workers exceeded the one-year effective dose limit of 50 mSv.

One member of the public received a dose of 1.62 mSv as a result of the transport of packages containing nuclear substances with passengers. That dose exceeded the regulatory limit of 1 mSv.

Operating performance

The CNSC conducted 1,313 operating performance inspections in 2016. It found 92% of licence holders in the commercial sector had fully complied with safety laws and regulations, as did 91.4% of holders in the academic and research sector, 88.2% of holders in the medical sector and 86.4% of holders in the industrial sector. The licence holders that did not fully comply with safety laws and regulations were required to take corrective measures, such as re-evaluating and revising their procedures, or retraining their workers.

Radiation protection

All licence holders are required to have a radiation-protection program that ensures that contamination levels and radiation doses received are monitored, controlled and maintained as low as reasonably possible.

Through 1,309 radiation-protection inspections carried out in 2016, the CNSC found that 91.8% of licence holders in the commercial sector, 91% of licence holders in the academic and research sector, 84.4% of licence holders in the industrial sector and 80.2% of licence holders in the medical sector returned satisfactory results. As the CNSC notes, large institutions such as hospitals hold several licences; a single issue in a corporate radiation-protection program can become evident in several inspections and thus reduce the institution’s overall compliance score.

Sealed-source tracking

NDT pipeline inspection

Pipeline inspection by non-destructive testing, using industrial radiography equipment that contains a sealed source.

Licence-holders are required to maintain and manage “sealed sources”: to reduce exposure, certain nuclear substances must be contained in a sealed capsule or bonded to a cover in a way that shields the substance from contact with people and the environment. In 150 inspections conducted in 2016, the CNSC found 94% compliance by the medical, commercial, industrial, and academic and research sectors. Non-compliant licence holders carried out corrective actions such as a complete verification of their sealed-source inventories.

The CNSC reports on its sealed-source tracking system on its website.

Reported events

The CNSC received 139 reports of events in 2016, including 45 malfunctioning or damaged devices, 20 spills or contaminations, 13 missing or found nuclear substances or radiation devices, 12 unplanned exposures, 5 security breaches, and 44 issues related to packaging or transport. In all cases, no worker or member of the public received a radiation dose exceeding regulatory limits, and the environment received no adverse exposure.