In a radiation hazard situation, radiation measurements aim to obtain as good a picture as possible of the radiation situation and its development. For example, if there was a serious accident at a nuclear power plant, the number of samples and locations to be measured would be large.
When assessing the urgency of the measurements, the size of the exposed population and the people most exposed are taken into account:
- The people who are most exposed to radiation are measured urgently.
- Samples or objects that cause the most radiation exposure are primarily analyzed, also taking into account the enrichment rate of radioactive substances.
- The focus will be on areas where deposition has occurred and where protective measures are needed. It is also important to clarify the boundaries of these areas.
- In the early and later phases of a large-scale radiation hazard situation, measurements are not primarily carried out in evacuated areas, but instead the measurement activities are concentrated in areas where people are present and/or where large quantities of daily food are produced.
In the early phase, measurements are needed to determine the level of contamination of the environment and human exposure. In this case, the most important thing is to obtain information on the dose rates of external radiation and the concentrations of radioactive substances in the air and deposition. The results of the measurements will be published on the website of the Radiation and Nuclear Safety Authority.
- Ulkoisen säteilyn annosnopeudet (Säteilytilanne tänään -sovellus) [sivua ei ole vielä englanninkielisenä]
- Ulkoilman radioaktiiviset aineet [linkki - sivua ei vielä ole]
As the situation progresses, radioactive substances in the air and deposition increase the concentrations of radioactive substances in food, drinking water and animal feed, making their concentration measurements the most important.
By restricting the use of food, internal radiation doses received by humans through food can be avoided. Information on the radioactivity of foodstuffs is also needed for the monitoring of food use, sales and export limits.
Among the raw materials related to primary production, milk, eggs, meat and grains are important. In order for food to be safe to eat, attention must also be paid to ensuring that food does not become contaminated during production in the food industry.
At a later phase of the radiation hazard situation, measurements are made of the products collected from the wild and game and fish.