Protective Actions are the simple steps we can take to reduce our radiation dose if we are affected by a radiation emergency.
Protective actions in practice
The three most effective protective actions for the period when the plume is airborne are:
- Shelter - This reduces inhalation dose by keeping radioactive gases and dusts out and reduces gamma shine by providing shielding and distance
- Evacuation - If done in time this prevents the plume dose pathways inhalation and cloud dose. If sustained after the plume has passed prevents resuspension and ground gamma dose;
- Stable Iodine - (for operating reactor accidents only) - This reduces the uptake of radio-iodine by the thyroid gland.
After the plume has passed the concern switches to the effect of deposited radionuclides and measurements will be made of radioactivity in foods and drinks and of external gamma radiation and appropriate advice will be given.
See Pathways page for more information.
Protective Actions in Literature
"Protective Actions" sometimes called "countermeasures", in this context, are the steps we take to protect workers, the public and the environment from a release
of radioactivity to the atmosphere.
The IAEA states that ''countermeasures are forms of intervention. They may be protective actions or remedial actions, and these more specific terms should be used where possible''
IAEA Safety Glossary, Terminology Used in Nuclear, Radiation, Radioactive Waste and Transport Safety.
A '''protective action''' is defined as ''An intervention intended to avoid or reduce doses to members of the public in emergencies or situations of chronic exposure.''
Longer term protective actions are those that are not urgent and may last for weeks or months such as relocation, agricultural countermeasures and remedial actions.
A '''Remedial Action''' is ''an action taken when a specified action level is exceeded, to reduce radiation doses that might otherwise be received, in an intervention situation involving chronic exposure.''
This IAEA terminology is not often used in the UK.
The Government view on the application of countermeasures can be found in the
National Nuclear Emergency Planning and Response Guidance.
The more recent Public Health England advice is also available
The older NRPB documents are still worth a read (Board Statement on Emergency Reference Levels)
and Application of Emergency Reference Levels of Dose in Emergency Planning and Response.
The IAEA view of countermeasures is given in IAEA General Safety Requirements, No. GSR Part 7, Preparedness and Response for a Nuclear or Radiological Emergency..
Protective Actions in REPPIR
REPPIR regulation 2(1) defines a protective action as "an action or actions taken in order to prevent or reduce the exposure of emergency workers, members of the public,
the environment or the contamination of property from ionising radiation in the event of a radiation emergency, and includes the provision of appropriate information to the public
in accordance with regulations 21 and 22".
Guidance (para 66) adds:
(a) Mitigatory action which is immediate action taken by the operator or other party, in relation to a radiological hazard on the premises, to:
(i) Reduce, and where possible prevent, the potential for conditions to develop that would result in exposure or a release of radioactive material requiring emergency
response action on and/or off the premises;
(ii) Mitigate source conditions that may result in exposure or a release of radioactive material that require, or are likely to require, urgent or longer-term protective
actions on and/or off the premises; and
(iii) Prevent escalation of an emergency and to return the facility to a safe and stable state.
(b) Urgent protective action which is aimed at reducing exposure to people prior to and during the early phase of a radiation emergency. It includes sheltering-in-place; administration of
stable iodine; evacuation; and restrictions on food and water supplies. Some of this action may be taken on a precautionary basis. In addition, other urgent protective actions, such as personal
decontamination, medical intervention and reassurance monitoring, may be required at an individual level and on a case-by-case basis, according to the prevailing circumstances.
(c) Longer-term protective action which is aimed at reducing exposure to people during the intermediate and long-term phase resulting from a radiation emergency (such as transition to an
existing exposure situation). This action includes continuing restrictions on food and water supplies; temporary and permanent relocation; and recovery action. Recovery action provides protection
from longer-term exposures from contamination of the environment and food supplies. Some longer-term protective actions, such as follow-up health surveillance, may be taken on a precautionary basis.