Requirements for people responsible for security-enhanced sources
The Code of Practice for the Security of Radioactive Sources requires that those responsible for security-enhanced sources take physical, administrative and personnel security measures to meet appropriate security outcomes, depending on the category of the radioactive source.
Under this risk-based security approach, Category 1, 2 and 3 sources (or aggregations) require the implementation of a security management system and security plan. The level of security measures to be undertaken is proportional to the risk of the source and the consequences of malicious use.
What must people responsible for radioactive sources do?
Those responsible for radioactive sources may apply the Code through the following steps.
Categorisation of sealed radioactive sources
The initial step in determining how the Code applies is for whoever is authorised by the EPA to be in possession of, and responsible for, a radioactive source to undertake the categorisation of each source, or the aggregation of sources, for which they are responsible.
The category of a source is determined by the ratio of the activity of the source to the dangerousness (D-value) of the radionuclide. Depending on that ratio, the source is categorised from 1 to 5.
Schedule B of the Code sets out D-values for radionuclides and details the methodology for categorising sources; some of the common radionuclides are listed in the table below.
Categorisation thresholds of common radionuclides
These thresholds apply to sources or aggregations of the same radionuclide. Those responsible for sources should apply the formula in Schedule B of the Code to aggregate sources of different radionuclides.
Radionuclide | Category 1 (TBq) | Category 2 (GBq) | Category 3 (GBq) | Category 4 (GBq) | Category 5 exemption levels (MBq) |
Am-241 | 60 | 600 | 60 | 0.6 | 0.01 |
Am-241/Be | 60 | 600 | 60 | 0.6 | 0.01 |
Cs-137 | 100 | 1000 | 100 | 1 | 0.01 |
Cf-252 | 20 | 200 | 20 | 0.2 | 0.01 |
Co-60 | 30 | 300 | 30 | 0.3 | 0.1 |
Cm-244 | 50 | 500 | 50 | 0.5 | 0.01 |
Ir-192 | 80 | 800 | 80 | 0.8 | 0.01 |
P-32 | 10,000 | 100,000 | 10,000 | 100 | 0.1 |
Pu-238 | 60 | 600 | 60 | 0.6 | 0.01 |
Po-210 | 60 | 600 | 60 | 0.6 | 0.01 |
Ra-226 | 40 | 400 | 40 | 0.4 | 0.01 |
Se-75 | 200 | 2000 | 200 | 2 | 1 |
Sr-90 | 1000 | 10,000 | 1000 | 10 | 0.01 |
Change of source details
When a sealed radioactive source contained in a device or kept on premises registered with the EPA is replaced, it is imperative that the person responsible for the source notifies the EPA of the new source details, so that reliable records of radioactive sources in the community can be maintained. A form is available from the EPA for this purpose.
Outcomes for security-enhanced sources
If the sources for which a person is responsible fall into Category 1, 2 or 3, a source security plan, which demonstrates how the requirements of the Code appropriate to the category of the source will be met, must be prepared. The outcomes to be achieved differ depending on the category of the source and the relevant security environment.
Category 1 security-enhanced sources
Category 1 sources are considered to pose the highest risk and are subject to the most stringent security requirements. Category 1 sources include industrial irradiation facilities, larger blood or research irradiators, and gamma knife devices.
When in use, or when being stored or transported, a Category 1 security-enhanced source must be protected by physical security measures capable of providing sufficient delay to allow immediate detection and assessment of an intrusion, and for a guard or police service to interrupt unauthorised removal of the source.
Category 2 security-enhanced sources
Category 2 sources include most blood and research irradiators and industrial radiography sources.
When in use, a fixed or mobile Category 2 security-enhanced source (or any Category 2 security-enhanced source when it is being stored or transported) must be protected by physical security measures capable of providing sufficient delay to allow immediate detection and assessment of unauthorised access to the source.
Category 3 security-enhanced sources
Category 3 sources include sources used in brachytherapy and larger fixed industrial gauges.
When in use, a fixed or mobile Category 3 security-enhanced source (or any Category 3 source when being stored or transported) must be protected by physical security measures capable of preventing unauthorised access to the source by human force.
Category 4 and 5 sources
Category 4 and 5 sources include low-dose brachytherapy units, most industrial gauges, and portable soil moisture and density gauges used in road building and agriculture.
Those responsible for these sources should apply safety-based security measures for Category 4 and 5 sources, which are outlined in the EPA registration conditions.
More detail on security measures is provided.
Page last updated: 03 April 2013
