Considerations for developing the protection strategy implied from

implemented through the pre-established emergency arrangements. However, recognizing that an emergency is unlikely to be identical to any of the scenarios considered at the preparedness stage, a capacity for flexibility and adjustment needs to be incorporated into the protection strategy at the preparedness stage. This includes consideration of arrangements for: (a) assessment, including the establishment of the relevant priorities for gathering information to support decision making; (b) revision and application of criteria; and (c) processes for adjusting or lifting protective actions or other restrictions. The level of flexibility, which is provided in the protection strategy and, thus, in the associated emergency plans, procedures and other arrangements, will strongly depend upon the time after the emergency onset, i.e. the phase of the emergency response (see Fig. 5).

FIG. 5. Emergency response phases [8].

In addition, the protection strategy needs to be continually adapted during the response as the emergency evolves (the adapted protection strategy, see Section 2), depending on the scale and phase of the emergency and on the amount and type of information available. Means and processes to be used for this adaptation are an important part of the strategy.

A range of temporal and spatial aspects needs to be considered when implementing the protection strategy which may have an impact on the development of the strategy at the preparedness stage as well. For large or prolonged releases, the impact of the emergency differs from one area to another, potentially resulting in different exposure pathways dominating in different areas (e.g. deposition, resuspension, ingestion) and different dominant radionuclides. The range of received, projected and residual doses varies spatially, hence it is to be expected that the optimum protective actions vary from area to area and with time, and the protection strategy needs to reflect this. The protection strategy for implementation needs to include a planned timescale for actions, broken down if necessary and where appropriate by areas which are similar in contamination and/or dose.

In conjunction with considerations about the non-homogeneous spread of contamination, it is possible that the pre-emergency demographic, economic, land usage and other factors will vary with area, again potentially leading to different protective actions. Furthermore, protective actions may be adjusted to take account of non-radiological factors (for example, to avoid dividing a population group or a community, decision makers may prompt evacuation over a wider area than what is expected based on the radiation monitoring results). It is necessary to determine the likely impact of actions in one area on another area. This will

indicate whether it is necessary to implement actions in a particular order to reduce adverse consequences in other areas. Issues such as discussed above might be faced in a response when the protection strategy needs to be implemented and, thus, they need to be considered in the development of the strategy and its justification and optimization.

4.2.1. Considerations for the urgent response phase

As soon as the emergency has been declared, prompt implementation of the protection strategy is of paramount importance to provide the best level of protection under the prevailing circumstances, even if very little information is available and uncertainties are large. During this phase, the protection strategy needs to be implemented according to the detailed emergency plans, procedures and other arrangements developed and agreed upon at the preparedness stage and corresponding to the protection strategy. The focus needs to be on the protection of those at highest risk for radiation induced health effects.

Urgent protective actions ideally are triggered by plant conditions (i.e. EALs) or other observable conditions. The protection strategy for the urgent response phase needs to be planned in detail at the preparedness stage to ensure its effectiveness, considering that during this phase there is insufficient time for data gathering, consultation and adaptation and limited information is available. Thus, it is essential that decisions related to the urgent response phase are made at the preparedness stage and consider what is to be undertaken, when, where and how.

However, it is recognised that specific conditions prevailing at the time during the urgent response phase may require flexibility in the protection strategy to enable its safe implementation. For example, severe weather conditions may render planned evacuation unsafe. Thus, it is important to consider such factors at the preparedness stage and include in the protection strategy in order to avoid the necessity of making unplanned adjustments in an emergency. Example conditions that may require adaptation of the pre-planned protection strategy during the urgent response phase include, but are not limited to:

− Destroyed infrastructure (e.g. by a serious natural event);

− Severe adverse weather conditions; and

− Unavailability of resources due to prior deployment for other purposes.

4.2.2. Considerations for the early response phase

As the emergency evolves and progresses into the early response phase, more information on the circumstances leading to the emergency and its consequences become available. In this phase, there is less urgency than in the urgent response phase, so improving the understanding of the situation comes also in focus with the implementation of the public protective actions.

Moreover, the urgent protective actions taken need to be reconsidered at this stage to determine whether the actions are appropriate and sufficient, and to adjust them as necessary.

It is at this time possible to begin to consider revising, justifying and optimizing the protective actions, and the adapted protection strategy, taking into account:

− How the potential or actual situation varies from the most similar scenario assumed in the basis for the protection strategy developed during the preparedness stage;

− How the situation may continue to evolve; and

− Whether protective actions and other response actions need to be adjusted or lifted (e.g.

if no longer justified).

The situation needs to be continually assessed in order to make informed adjustments about the extent to which the protection strategy continues to be appropriate for the hazards posed

by the prevailing circumstances. Any adaptation of the protection strategy needs to be based on an iterative process of justification and optimization that takes account of a range of radiological and other relevant factors, discussed in Section 5. The objective needs to be to ensure that the adapted protection strategy continues to do more good than harm and be the best under the prevailing circumstances. The reference level may need to start playing a role in this phase as a tool to guide further efforts and to help judging effectiveness of the protection strategy implemented by that time. However, even during the early response phase, there is likely to be limited time for comprehensive justification and optimisation, assessment of effectiveness and consultation (see Sections 5 and 6) and, thus, more detailed planning for the protection strategy might be appropriate for this phase as well. Still, some practical aspects may call for attention at certain point of time during the early response phase.

Examples of such aspects are provided in Table 2.

TABLE 2. EXAMPLES OF PRACTICAL ASPECTS TO CONSIDER WHEN ADJUSTING THE PRE-ESTABLISHED PROTECTION STRATEGY DURING THE EARLY RESPONSE PHASE

Types of consideration Examples of necessary information, when and if available

The current radiological or non-radiological situation

− Whether any individuals at immediate risk due to radiological or non-radiological hazards.

− The current picture of the local region and infrastructure and how has this changed from the emergency plan as a consequence of the emergency.

− Estimates of projected and residual dose.

− The position with regard to agriculture and water supplies.

− The adequacy of the food and water supplies in areas where restrictions are necessary and where people are present.

The actual conditions of the

− Meteorology during any release of radionuclides and current weather conditions and future weather predictions.

The protective actions that have already been implemented

− The effectiveness of the implemented and planned protective actions at reducing exposures in this emergency.

− The uptake of the protective actions by the population.

− The potential for negative impacts from continuation of the protective actions.

Whether or not the protective

actions that have been

implemented can be lifted or modified

− Whether or not the protective actions are still effective.

− Whether or not the protective actions are still justified.

− Whether any other required activities to facilitate lifting of the protective actions have been undertaken.

Types of consideration Examples of necessary information, when and if available

− Whether any past protective actions preclude taking additional protective actions.

− Positive and negative effects and other limitations associated with the proposed protective actions (see Appendix III).

− For this particular emergency, what is the likely effectiveness of actions in dose reduction (if the effectiveness of an action is unclear, a pilot study may be needed to determine whether it is appropriate for use on a larger scale).

− Optimum initiation timings of proposed protective actions, relative timings and priorities in regard to the implementation of each and also to existing protective actions, applicability and priorities in each affected area.

− Collation of information on data for input to decisions on recovery and decontamination (these are given elsewhere but include resources available, estimated areas affected, prioritisation of areas, estimated waste arisings and disposal routes).

Other circumstances that may be impacting the pre-determined

protection strategy and/or

arrangements

− Destroyed infrastructure due to a natural disaster.

− Severe and adverse weather conditions.

− Unavailability of resources due to their prior deployment for other purposes.

Other considerations need also to be included in the justification and optimization processes, such as (a) feasibility; (b) acceptability and public trust; (c) possible adverse psychological and sociological consequences, as discussed in more detail in Section 5. The level at which all these considerations are tackled during this phase will increase with time.

Throughout the early response phase, the protection strategy needs to be continuously reassessed and adapted on the basis of the prevailing conditions, as the time allows for effective protection of the public. The reassessment of the situation based on actual circumstances may lead to decisions to lift protective actions that are no longer justified and/or to implement new justified actions. The rationale for each adapted protection strategy needs to be transparent, documented and communicated with relevant authorities and interested parties. It is necessary to specify relevant criteria and to explain and justify changes from the earlier protection strategy with reference to the conditions considered (including radiological and other factors).

Any limitation to what and when can be done at this stage needs to be well thought and reflected in the protection strategy for this phase.

4.2.3. Considerations for the transition phase

As the emergency progresses, there is a progressively greater understanding of the precise nature of the emergency and the circumstances surrounding it. Therefore, decision making needs to be based on actual conditions rather than pre-planned response, to a progressively greater extent. It is expected that, before or during the transition phase, the emergency situation is brought under control and that the radiological situation is characterized in detail.

This information may then be used to further adapt the protection strategy, as appropriate. At this stage, it is possible to apply the justification and optimization processes more rigorously, including consultation with interested parties. For large emergencies, there need to be an increasing focus on activities to allow social and economic activity to resume.

All aspects for consideration in adapting the protection strategy outlined for the early response phase also apply to the transition phase with the aspect of having more time to shape the response better to the actual situation using all necessary means. Additional considerations in the transition phase that need further consideration in the protection strategy include:

- Primary objective and prerequisites to enable the emergency to be terminated and allow social and economic activity to be resumed as appropriate to the circumstances;

- The change in what acceptable reference level is to enable the transition to an existing exposure situation.

As in the early response phase, it is important to ensure that any adaptations to the protection strategy in the transition phase are transparent, documented and communicated with relevant authorities and relevant interested parties, following agreed processes in the strategy at the preparedness stage. As indicated above, it is necessary to specify the relevant criteria and conditions considered (both radiological and non-radiological) in this process. Also, as for the early response phase, various actions (individually or in combination) need to be appropriate in the transition phase, and it may be anticipated that the adopted protection strategy needs to be further developed in detail for different areas and with a clear timescale for each area rather than this to be done in the strategy at the preparedness stage. It is important to ensure that the reasons for changes in the protection strategy over time, for the circumstances of the particular emergency, are clear and appropriately explained. Further guidance on factors to consider in the protection strategy for the transition phase is provided in GSG-11 [8]. The general and specific prerequisites provided in Section 3 of GSG-11 [8] help in identifying possible actions and activities to be considered in the protection strategy for this phase.

There is less urgency associated with the transition phase than either the urgent or early response phases. Therefore, the level of planning in preparedness for the transition phase is less detailed than for the earlier phases, since there is more time available to adapt the protection strategy to the particular circumstances. During the preparedness stage, it is therefore important to establish a flexible general framework for decision making that may be applied in the transition phase, taking account of the following priorities for this stage:

− Full characterization of the radiological and non-radiological situation;

− Adaptation of the protection strategy by means of comprehensive justification and optimization processes, including consultation with interested parties;

− Facilitation of the resumption of social and economic activity with care given to the well-being of those affected.

5. JUSTIFICATION AND OPTIMIZATION OF PROTECTION AND SAFETY