Regulatory Guide - Radiation incidents (ARPANSA-GDE-1749)

Last updated date:	Reason for update:
25 February 2026	Periodic review; alignment with RAD processes.

This Regulatory Guide informs licence holders on the actions to be taken if a radiation incident occurs, when ARPANSA must be notified, and how to make such a notification.

Associated forms

Report a notifiable incident

Introduction

Sections 57A & 58 of the Australian Radiation Protection and Nuclear Safety Regulations 2018 (the Regulations) places obligations on licence holders to prevent, control and minimise incidents; in doing so they must take into account human and organisational factors.

Incidents that must be reported to ARPANSA are defined, as are the actions that must be taken by the licence holder if an incident occurs.

An incident is:

any unintended event, including an operating error, equipment failure, initiating event, accident precursor, near miss or other mishap; or
any unauthorised act, whether or not malicious

the consequences or potential consequences of which are not negligible from the point of view of protection and safety.

This includes events where controlled apparatus or material had the potential to result in an exposure to radiation to any person or the environment, outside the range of that normally expected for a particular practice.

Notifiable incidents

A notifiable incident requires immediate action and must be reported to ARPANSA within 24 hours, and a written report must be provided to ARPANSA within 14 days.

A notifiable incident means any of the following:

an incident that exposes a person to a dose of ionising radiation that exceeds an effective dose limit mentioned in section 77 or an equivalent dose limit mentioned in section 79 of the Regulations
an incident involving a diagnostic or interventional medical procedure resulting in an observable acute radiation effect
an incident involving exposure to non-ionising radiation from controlled apparatus that exceeds the non-ionising radiation exposure limits or results in noticeable eye or skin damage
a theft or loss of controlled material or controlled apparatus, other than controlled material or controlled apparatus in Group 1
an incident involving the release of controlled material if the result of the activity value division steps* for the controlled material is greater than 10⁴
an incident involving transport of a package of controlled material if the result of the activity value division steps for the controlled material is greater than 10⁴ and the package is damaged in such a way that safety provisions are degraded.

* activity value division steps for sources or controlled materials are the following:

(a) first, divide the activity of each nuclide in the sources or controlled materials by the activity value set out in Part 1 of Schedule 1 of the Regulations for the nuclide;
(b) secondly, if there is more than one nuclide in the sources or controlled materials, total the result of paragraph (a) for each nuclide.

Note: Section 5 of the Regulations affects how the activity of a parent nuclide mentioned in Part 2 of Schedule 1 (or marked ^a in Part 1 of Schedule 1) is worked out, by providing for inclusion of the activity of certain progeny nuclides that are included in secular equilibrium with the parent nuclide.

Worked example

Suppose there are two vials in a laboratory cupboard, one containing 10 MBq of Co-60 and the other containing 100 MBq of Cs-137. Assume a fire destroys the cupboard and the vials and all activity is released. Is this a notifiable incident?

Schedule 1 Part 1 of the Regulations gives activity values of 10⁵ Bq and 10⁴Bq for Co‑60 and Cs-137 respectively. If all activity is released, the result would be:

(10⁷/10⁵) + (10⁸/10⁴) =10² + 10⁴ which is > 10⁴ Hence this is a notifiable incident

What to do if a notifiable incident occurs

Preserve the site

Priority should be given to controlling and mitigating the consequences of the incident. However, as far as possible, it is essential that the integrity of the incident site is preserved to allow an analysis of the conditions at the site and a thorough investigation as to the cause(s) of the incident.

Special attention should be paid to the importance of securing the site or the facility to prevent any destruction or cross-contamination of the physical information as well as to protect responding personnel and others.

See Regulatory Guide: Radiation incident site preservation for further information.

Notify ARPANSA

Within 24 hours of a notifiable incident occurring the licence holder must tell ARPANSA.

Call the ARPANSA 24/7 Duty Officer on (03) 9432 5384
As soon as possible, within 14 days, complete an Incident Notification Form via the RAD Portal - or if that is not possible send it to licenceadmin@arpansa.gov.au.

Investigate and provide a written report within 14 days

When investigating a radiation incident the following questions should be considered:

What happened?
How did it happen?
Why did it happen?
As described in the holistic safety guide, consider the whole system of technical (e.g. human-machine interface design), human (e.g. cognitive demands, fatigue), and organisational (e.g. leadership, safety culture) factors. Also consider the interactions between these factors (e.g. how individuals use technology to communicate safety-critical information across multi-disciplinary teams).
Was the severity of the incident and its likelihood of occurrence accurately reflected in the risk assessment?

These questions will help identify the causes and contributing factors with the ultimate aim to improve safety.

A written report must be provided to ARPANSA that contains an account of the incident and its consequences including where possible:

an estimate of the dose received by any person
an assessment of any impact on the environment
an assessment of technical, human and organisational factors that contributed to the incident
any corrective action taken as a result of the incident
actions taken to prevent the recurrence of similar events
the impact on safety
identified security implications.

NOTE: If the report is not final it should still be submitted within 14 days and be clearly marked as preliminary. The final version must be provided as soon as practicable and within a reasonable timeframe.

Review of plans and arrangements

Following a notifiable incident the licence holder must review and update plans and arrangements for managing safety. This review should include:

the design process for equipment, or processes relevant to the incident
the performance of the risk assessment
any review or safety approval system that authorised an activity which led to the incident.

The licence holder must complete the review within 6 months of the incident happening and must provide the CEO with a written summary of the outcome of actions resulting from the review within 7 months of the incident happening. The CEO may extend these periods on request.

Reporting other incidents

Any other incidents - such as operating errors, equipment failures, initiating events, accident precursors, near misses or other mishaps - that are not notifiable within 24 hours should be reported to ARPANSA as part of routine compliance reporting. This can be completed via the RAD Portal at any time.

This allows ARPANSA to follow-up as necessary especially where there may be lessons for other licence holders or the industry more broadly.

Disclosure of information

For incidents of the type mentioned in the National Directory for Radiation Protection (2^nd Edition, 2021) (NDRP) de-identified information will be included in the Australian Radiation Incident Register (ARIR), Australia's national database of incidents and events resulting from activities involving radiation.

ARPANSA may also submit relevant information to international registers such as that maintained by the IAEA for events on the International Nuclear and Radiological Event Scale (INES).

ARPANSA may also share information with other regulatory agencies including safety and state and territory radiation protection regulatory bodies where this is required.