Agustín Navarro_GIETMA: There is a wide range of risks that can trigger evacuation

What types of hazards or emergencies may require population evacuation?

There is a wide variety of risks that may necessitate evacuation. On the one hand, there are hazards stemming from human activity: from residential building fires to more specific threats such as chemical incidents (e.g. a fire at a chemical facility producing a toxic plume), radiological or nuclear risks (such as damage to a hospital-use radiological source), and biological hazards (facilities housing patients with highly contagious diseases like haemorrhagic fevers). All these situations may require moving the population to a safe zone.

On the other hand, natural hazards can also prompt evacuation. These include wildfires, floods, heavy snowfalls and volcanic eruptions, such as the 2021 eruption on La Palma island, where lava flows, infrastructure collapse under volcanic ash, and toxic gas emissions combine to pose significant threats.

What evacuation plans would be implemented in the event of a radioactive release from a nuclear power plant?

Several key factors must be considered when planning an evacuation. To support decision-making, there are various plans and guidelines designed to serve as operational frameworks. In the event of an emergency at a nuclear facility, the Basic Nuclear Emergency Plan (PLABEN) would be activated. PLABEN sets out the applicable rules and criteria for handling such emergencies.

It mandates the development of several interlinked plans: The Site Emergency Plan (SEP) for nuclear facilities; the Nuclear Emergency Plan (NEP) for the province where the facility is located; and the Municipal Emergency Plan (PLAMEN), which governs response activities in municipalities near the plant. These plans operate in coordination and are supported at national level by the Central Nuclear Emergency Plan for Response and Support (PENCRA).

What actions are foreseen within these plans?

These plans include protocols that anticipate a range of possible scenarios or incidents, particularly since the Fukushima disaster, after which many additional contingencies have been incorporated. In the event of an incident at a nuclear facility, a situational assessment is conducted before any measures are taken. The type and severity of the incident and the surrounding environment are key considerations. Based on this assessment, a range of urgent actions and protective measures, such as shelter-in-place directives, radiological prophylaxis, and evacuation, may be triggered. The applicability of each measure must be carefully evaluated.

Authorities must then determine the potential impact on the population, environment and animals. Variables such as the quantity of radioactive material released, local radiation dose rates, wind speed and direction, distance of affected populations, and other meteorological conditions all influence this analysis. Additional considerations include the number of people affected, whether vulnerable individuals are present, and the availability of evacuation resources. In addition to assessing the means available for evacuation, it is necessary to assess whether decontamination of the personnel to be evacuated is necessary and where to relocate them. Authorities must also assess the need for decontamination and determine safe relocation areas.

Once the Emergency Commander authorises evacuation, a comprehensive evacuation plan is drawn up to ensure the operation is carried out in a safe, swift and orderly manner. Resource coordination is essential to optimise the process and ensure the protection of evacuees. An evacuation sequence is established, beginning with zones at highest or immediate risk, and progressing to areas at lower risk. Evacuation then proceeds along designated routes. In cases where the population has been exposed to radiation, evacuees will be processed through decontamination stations, where trained personnel carry out the decontamination protocol and monitor for contamination. Only once individuals are confirmed to be decontaminated are they cleared for relocation to a safe area.

What other types of evacuation may be necessary in an emergency, and what measures would they require?

Evacuations may be carried out either because an incident has already occurred or due to the anticipation of an imminent threat. One type of evacuation, beyond the general evacuation of a population, involves the evacuation of a specific facility. In such cases, while the measures required are broadly similar, there is the advantage that employees are usually familiar with the evacuation routes outlined in the facility’s emergency plans. Additionally, the use of public address systems or light signals can help maintain order.

It is also important to note that evacuations are not limited to the personnel affected by the incident. Emergency services and response teams may also be required to withdraw from the intervention area in situations where the incident exceeds the capacity of available resources or where there is a clear and present danger to responders. Examples of such scenarios include the risk of a BLEVE (Boiling Liquid Expanding Vapour Explosion) or an imminent boil-over event.

How important are company and industry safety protocols and action plans in prevention?

Nuclear power plants, along with various other types of industrial facilities, have extensive safety protocols and emergency action plans tailored to the size, complexity and operational risk of each site. These protocols are essential in preventing incidents. Regular simulation exercises, often involving the Military Emergency Unit (UME) and other agencies. In the event of a real emergency, all these entities would participate jointly and actively in advising and coordinating the response efforts, as would the Nuclear Safety Council (CSN) in this case.

It is essential to emphasise the importance of developing comprehensive emergency plans and conducting regular drills, not only those mandated for industrial sites but also those implemented at the municipal level. These should be based on the specific risks identified for each locality. Such preparation greatly facilitates a coordinated emergency response and enhances the effectiveness of intervention teams during real incidents.

Finally, if you are required to evacuate or shelter in place due to an emergency, it is critical to remain calm and follow the instructions issued by the authorities and emergency services. Doing so is vital not only for your own safety but also for the safety of those around you.