Due to the nature of nuclear reactor emergencies, where the hazard and its location are known and, the extent of the hazard is normally verifiable, protective action decision-making can be categorized according to the following phases of the emergency:

  1. Urgent Response Phase
  2. Early Response Phase
  3. Transition Phase
  4. Recovery (See the PNROP for more details)

N.1 Urgent Response Phase

The Urgent Response Phase starts with an initial notification from the reactor facility of a General or Onsite Emergency notification category, which may require urgent protective and operational actions to deal with the immediate effects of radiation.

Upon receipt of an initial notification from the reactor facility of an ongoing or imminent emission, protective measures should be implemented (subject to operational situation considerations), based on a conservative estimate of the situation because time or data may not be available to carry out a comprehensive assessment of imminent risk. These protective measures shall be detailed in the applicable site-specific implementing plan and may include sheltering-in-place, evacuation, and ITB.

In situations where a release is not imminent or ongoing, decision-making should commence as soon as data is available (i.e., status of affected reactor(s)’ control, cooling, and containment) and well before exposure is expected to occur. This is accomplished with an assessment of projected doses, compared against the GC (Annex Q ), to determine the need for protective measures (Annex L).

Ingestion control measures shall be directed as appropriate. The measures may be modified in later phases based on the results of environmental field monitoring of food, milk, and water. The following additional protective measures are not associated with either a numerical intervention level (GC or OILs) and may be directed in combination with any of the protective and precautionary measures listed in Annex L:

  1. protective clothing
  2. respiratory protection
  3. self-decontamination

Population monitoring and medical management would begin during the Urgent Response Phase of a nuclear response (See Annex S ).

N.2 Early Response Phase

The Early Response Phase begins (and, by extension, the Urgent Response Phase ends) once the nuclear release is brought under control (though not necessarily contained), permitting environmental radiation surveys to continue, radiological sampling to be undertaken, and decision-making to be based on actual dose rate and radiological contamination measurements.

Evacuation and/or temporary relocation are the preferred protective measures during the Early Response Phase to prevent external exposure from deposited radioactive particles (e.g., ground contamination) as well as to prevent internal exposure from inhalation of radioactive particulates.

Ingestion control measures shall be directed as appropriate based on the results of environmental field monitoring of food, milk, and water.

A technical assessment of actual environmental radiation monitoring results applied against OILs (Annex Q.2) should inform the decision-making process to determine the need for both ingestion and exposure control measures.

The developing situation should be continuously re-assessed, and appropriate decisions made to apply protective measures and rescind those no longer necessary.

During the Early Response Phase, the CEM or designate (e.g. PEOC Commander) may recommend other, practical dose reduction measures to the public. Such measures may be implemented in combination with the measures described in this Annex or may simply be recommended to provide an additional level of protection against possible radioactive material present in the air or on the ground. Implementation of these measures are not based on GC or OILs and include:

  1. Respiratory protection, such as covering of the nose and mouth with available material that can filter particulates when present in the air
  2. Self-decontamination, including removing and bagging contaminated clothing, showering, and decontaminating surfaces of critical areas and objects
  3. Staying indoors to the extent that it is practical, e.g., only conducting outdoor tasks when necessary (e.g., seeking medical attention, buying foodstuff and necessities).

Advice regarding these measures shall be issued through the emergency bulletin process (See Section 8.7.2.2) as well traditional public communications methods.

All technical assessments shall be evaluated in the context of operational factors and public policy (e.g., psychosocial and economic) considerations. Such considerations shall provide an overall assessment of the risks and costs associated with various protective measures to provide for decision-making that optimizes public health, safety, and welfare.

The Early Response Phase starts to overlap with the Transition Phase once there is no potential for further releases and the need for early protective actions diminishes. The Early Response Phase ends at the moment the Recovery Phase begins.

Population monitoring and medical management would continue during the Early Response Phase of the response (See Annex S ).

N.3 Transition Phase

The Transition Phase can begin when the radiological environment has been characterized to the point where the risk to recovery workers is fully understood and manageable. The transition to recovery in these areas may proceed independent of ongoing Early Response Phase activities, including those in other areas.

The imposition and rescinding of protective measures, as well as the distinction between the first three phases, may not be uniform across the affected area as contamination levels may differ. Relevant partners and affected communities should be consulted and engaged early and often when developing and implementing Recovery Phase long-term protective action strategies.

The practical dose reduction measures detailed in the Early Response Phase are also applicable to the Transition Phase.

During both the Transition Phase and the Recovery Phase, recovery operations will be controlled and coordinated through a recovery management organization (RMO). Establishing the RMO is not a mandatory action when the PEOC is activated but should be considered at the earliest practical opportunity. As the nuclear emergency stabilizes, recovery operations will require planning for the transfer of operational control to the RMO.

N.4 Recovery Phase

Recovery is the final stage in responding to a nuclear emergency. The goal during the Recovery Phase is to return Ontario to a state of normalcy as quickly and effectively as possible, to the extent practically achievable. Recovery operations may begin before to the Transition Phase is complete. At this time, oversight of operations transfers from the PEOC Commander to the RMO Commander.

Recovery operations will be managed by the RMO (Figure N – 1). Recovery Phase decision-making should focus on adjusting or rescinding of protective measures imposed during the previous phases with the goal of reducing environmental radiation to appropriate levels established in consultation with relevant partners and affected communities, in order to improve living conditions and resume social and economic activities.

Recovery Phase decision-making should be based on ongoing environmental and assurance monitoring results and continuous re-assessment of the radiological situation in order to optimize long-term protective actions and manage the long-term radiological exposure situation.

The Recovery Phase is detailed in the Provincial Nuclear Recovery Operations Plan.

This diagram is for visual reference only. See the text below this figure for the full description.

This diagram illustrates the Recovery Management Organization (RMO) structure during full activation. A detailed description of the diagram follows the image.

Figure N – 1 : RMO Full Activation Organization

The diagram illustrates the Recovery Management Organization (RMO) structure during full activation. The Lieutenant Governor in Council and the Premier have the highest authority, followed by the Cabinet Committee on Emergency Management. Directly beneath them is the Deputy Minister's Steering Committee on Emergency Management, which connects to the Commissioner of Emergency Management. The Commissioner links to the RMO, which includes an Information Officer, Recovery Ops Commander, and a Safety Officer. Below this group are six functional sections: Operations, Planning, Logistics, Finance and Administration, Public Information Management, and Scientific. The Recovery Management Organization (RMO) links to Ministry Recovery Operations Centres and Municipal/ Regional Recovery Operations Centres. Ministry Recovery Operations Centres are ministries that focus on individual recovery responsibilities, while Municipal and Regional Recovery Operations Centres oversee localized recovery projects.