• sheltering (instructing the population to stay inside)
• evacuation (urgent moving of the population from the contaminated area)
• iodine prophylaxis (saturating of the thyroid gland with stable iodine in order to prevent intake of the radioactive iodine)

Among the most significant long-term countermeasures are:

• temporary relocation (relocation of the population from the contaminated area for a period of up to two years)
• permanent relocation
• food countermeasures (reduction of the contamination level of foodstuff, restrictions on consumption of contaminated food)
• agricultural countermeasures (restrictions on consumption of contaminated feedstuff, modifications of agricultural practices)

The decision making process related to the implementation of the countermeasures is very complex. Namely, each of the countermeasures beside the benefits (reduction of introduced radiation doses), causes more or less significant side effects.