Advisory Note: Use of the term ‘incident’ as defined in the Planned Exposure Code

Summary  

  • When referring to an accident or unauthorised act, the term ‘incident’ should be used as far as possible as this is consistent with international best practice in radiation protection and nuclear safety. 
  • An incident is a term that captures accidents, unauthorised malicious acts, and any other incident, situation, occurrence or event, the consequences or potential consequences of which are not negligible from the point of view of protection and safety. 
  • The Australian Radiation Incident Register (ARIR) is Australia's national database of radiation or radioactivity ‘incidents’.

Note to readers  

This advisory note provides explanation of the practical application of the term ‘incident’ as defined in the RPS C-1: Code for Radiation Protection in Planned Exposure Situations (Rev. 1) (ARPANSA 2020), herein referred to as the Planned Exposure Code.  

What is an Incident?  

The Planned Exposure Code gives meaning to an ‘incident’ as: 

Any unintended event, including operating errors, equipment failures, initiating events, accident precursors, near misses or other mishaps, or unauthorised act, malicious or non-malicious, the consequences or potential consequences of which are not negligible from the point of view of protection and safety.  

In practice this term is all-encompassing, capturing accidents, unauthorised malicious acts, and any other incident, situation, occurrence or event, the consequences or potential consequences of which are not negligible from the point of view of protection and safety. 

The flow of information about any incident is initiated by a licensee having identified an incident then communicating it to the relevant regulatory authority, usually without delay.   

The Guide for Radiation Protection in Emergency Exposure Situations, RPS G-3 (ARPANSA 2019) uses the generic term emergency throughout, which may be interpreted in reference to a radiological or nuclear incident, accident or event. The guide defines an emergency as: 

A non-routine situation (incident or accident) or event that necessitates prompt action, primarily to mitigate a hazard or adverse consequences for human health and safety, quality of life, property and the environment. 

The term ‘incident’ is not expressly defined in the guide however it is intended to be read in conjunction with the Planned Exposure Code and the definition therein. 

International best practice in radiation protection and nuclear safety and the term ‘incident’  

In 2018 an Integrated Regulatory Review Service (IRRS) mission reviewed Australia’s framework for radiation protection and nuclear safety against the International Atomic Energy Agency (IAEA) General Safety Requirements Part 3 (IAEA 2014). 

These safety standards use ‘incident’ across many areas of radiation protection and nuclear safety. For example, in the areas of emergency preparedness, a fundamental principle is that arrangements must be made for emergency preparedness and response for nuclear or radiation incidents. 

The definition of incident in the Planned Exposure Code was adopted without alteration from the IAEA General Safety Requirements Part 3.  

Use of the term ‘incident’ as defined in the Planned Exposure Code should be used as far as possible as this is consistent with international best practice in radiation protection and nuclear safety.  

Interchangeability of ‘incident’ and ‘accident’ 

When referring to an accident or unauthorised act, the term ‘incident’ should be used as far as possible. 

Consider a scenario where a person commits an unauthorised act by stealing a high activity source with the intent of causing malicious harm. This is not an accident as it was unauthorised and intentional. This is a security incident. For any unauthorised act, malicious or non-malicious, ‘incident’ and ‘accident’ are not interchangeable. The term ‘accident’ should not be used to refer to unauthorised acts. The term ‘incident’ should be used to refer to unauthorised acts.  

Consider an unintended event with a high activity source, which occurs while undertaking an authorised planned exposure. It is the unintended nature of the event that qualifies the event as an accident. Where an incident happens unintentionally and unexpectedly the term ‘incident’ may be used (interchangeably with the word ‘accident’) to refer to an unintended event.  

International Nuclear and Radiological Event Scale (INES) 

The International Nuclear and Radiological Event Scale (INES) was developed in 1990 by the IAEA as a tool for communicating the safety significance of nuclear and radiological events to the public. 

In Australia using the INES scale for early notification of incidents to the regulator is not advocated. For the purpose of a licensee communicating information about an incident, use of the INES rating can be confusing and add unnecessary complexity. INES gives specific meaning to the terms ‘accident’ and ‘incident’ and they are not interchangeable. For example, an ‘INES accident’ means an event rated at Level 4 or above. A licensee may wish to report an ‘accident’, but it may only be Level 2 which is regarded as an ‘incident’ not an ‘accident’ on the INES rating scale.  

It is interesting to note that the US Nuclear Regulatory Commission (USNRC 2021) does not require its licensees to classify events or to provide off-site notifications using the INES scale. 

Australian Radiation Incident Register (ARIR)  

The National Directory for Radiation Protection (ARPANSA 2017) sets out the kinds of events that are to be reported by regulators as an ‘incident’. The definition of ‘incident’ from the Planned Exposure Code fits well with this.  

The Australian Radiation Incident Register (ARIR) is Australia's national database of radiation or radioactivity incidents. The purpose of the ARIR is to raise awareness on where, how and why incidents and events occur, and how they can be best prevented. Reports are provided by Commonwealth, State and Territory radiation protection authorities.   

At the licensee-regulator communication interface a range of terms are used across jurisdictions within Australia. The term ‘dangerous event’ is commonplace in the NT, TAS and QLD; the term ‘radiation accident’ is used in SA and NSW while ‘radiation incident’ is used in the ACT, VIC and WA.  

These events, accidents and incidents are initially reported to the regulator using a range of terms, but all are reported as ‘incidents’ to the ARIR. 

It is recognised that universal use of the term ‘incident’ may not be possible in all situations. However, the term ‘incident’ should be used as far as possible, as this terminology is most compatible with the ARIR, the Planned Exposure Code and international best practice in radiation protection and nuclear safety. 

References  

ARPANSA 2021. National Directory for Radiation Protection (2nd Edition). Australian Radiation Protection and Nuclear Safety Agency [National Directory for Radiation Protection (2021)

ARPANSA 2019. Guide for Radiation Protection in Emergency Exposure Situations RPS G-3. Australian Radiation Protection and Nuclear Safety Agency [Radiation Protection Series G-3 | ARPANSA

ARPANSA 2020. Radiation Protection in Planned Exposure Situations Rev. 1. Radiation Protection Series C-1. Australian Radiation Protection and Nuclear Safety Agency 2020. [https://www.arpansa.gov.au/regulation-and-licensing/regulatory-publications/radiation-protection-series/codes-and-standards/rpsc-1]  

IAEA 2014. International Atomic Energy Agency Safety Standards Series No. GSR Part 3. [Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards | IAEA

USNRC 2021. International Nuclear and Radiological Event Scale (about emergency preparedness), Website Advice, [International Nuclear and Radiological Event Scale (about Emergency Preparedness) | NRC.gov