responds to emergencies will be part of the licencing basis. In the case of a facility, the safety analysis report (SAR), and the operating limits and conditions (OLC) will also be key documents of the licensing basis. In general, proposed changes to a facility that are within the bounds of its approved licensing basis have already been approved by ARPANSA and are therefore unlikely to have significant implications for safety. However, the significance of any changes that could impact on the boundary established by the licensing basis should be assessed against the criteria of this guide. In addition, if any of the following apply to the proposed change, it is likely to have a significant implication for safety (and therefore requires prior approval): Results in more than a minimal increase in the likelihood or consequences of an accident or malfunction previously evaluated in the SAR. Create the possibility of an accident or malfunction of a different type to what was evaluated in the SAR. Results in a radiological constraint or consequence as described in the SAR being exceeded or increased. Involves departure from a method of evaluation described in the SAR used in establishing the design or in the safety analysis. It should be noted that reviews by the licence holder to determine the applicability of section 63 or 64 of the Regulations do not necessarily aim to determine if the proposed change is good or bad. The licence holder is expected to have other processes for determining if the proposed change is justified or warranted. The review focuses merely on whether prior approval by ARPANSA is required. A cumulative effect of two or more relevant changes that individually do not have significant implications for safety must also be considered. This principle addresses the scenario where successive minor changes can, over time, lead to a significant change in the safety of controlled sources or facilities (organisational drift). Licence holders should be able to show that cumulative effects have been considered when making relevant changes. Consequence thresholds for section 63 The table below provides the thresholds above which ARPANSA considers a change to have significant implications for safety. In order to categorise changes, licence holders must have systems in place to evaluate the risk of certain changes. ARPANSA may ask licence holders to provide documentation to support their evaluation of a change considered unlikely to have significant implications for safety. Note: Appropriate review allows licence holders to know and manage the risks associated with their operation Implication for safety Threshold for section 63
responds to emergencies will be part of the licencing basis. In the case of a facility, the safety analysis report (SAR), and the operating limits and conditions (OLC) will also be key documents of the licensing basis. In general, proposed changes to a facility that are within the bounds of its approved licensing basis have already been approved by ARPANSA and are therefore unlikely to have significant implications for safety. However, the significance of any changes that could impact on the boundary established by the licensing basis should be assessed against the criteria of this guide. In addition, if any of the following apply to the proposed change, it is likely to have a significant implication for safety (and therefore requires prior approval): Results in more than a minimal increase in the likelihood or consequences of an accident or malfunction previously evaluated in the SAR. Create the possibility of an accident or malfunction of a different type to what was evaluated in the SAR. Results in a radiological constraint or consequence as described in the SAR being exceeded or increased. Involves departure from a method of evaluation described in the SAR used in establishing the design or in the safety analysis. It should be noted that reviews by the licence holder to determine the applicability of section 63 or 64 of the Regulations do not necessarily aim to determine if the proposed change is good or bad. The licence holder is expected to have other processes for determining if the proposed change is justified or warranted. The review focuses merely on whether prior approval by ARPANSA is required. A cumulative effect of two or more relevant changes that individually do not have significant implications for safety must also be considered. This principle addresses the scenario where successive minor changes can, over time, lead to a significant change in the safety of controlled sources or facilities (organisational drift). Licence holders should be able to show that cumulative effects have been considered when making relevant changes. Consequence thresholds for section 63 The table below provides the thresholds above which ARPANSA considers a change to have significant implications for safety. In order to categorise changes, licence holders must have systems in place to evaluate the risk of certain changes. ARPANSA may ask licence holders to provide documentation to support their evaluation of a change considered unlikely to have significant implications for safety. Note: Appropriate review allows licence holders to know and manage the risks associated with their operation Implication for safety Threshold for section 63
reg-rc-sup-250a_0.docx