Radiation safety

Working in a so-called uncontrolled area is no different from other industrial work. Those systems that contain or may contain radioactive materials are located within the so-called controlled area and are closely monitored.

Radiation safety at Loviisa power plant

Working at a nuclear power plant

Working in a so-called uncontrolled area is no different from other industrial work. Those systems that contain or may contain radioactive materials are located within the so-called controlled area and are closely monitored.

The controlled area is demarcated and access and egress is through personnel monitors. At the perimeter, it is ensured that everyone entering the control area is equipped with basic equipment and dosimeters. Nothing may be taken out of the control area without careful measurements.

Radiation and the environment

Normal operation of the Loviisa nuclear power plant results in very low radiation doses to the environment. The annual radiation dose to the population in the vicinity from the operation of the plant is so low that it cannot be measured.

Calculated, it is at most on the order of a thousandth of the dose from natural sources. This means that a person living in the immediate vicinity of the power plant all year round would have an average annual exposure of about 0.001 mSv from the emissions of the power plant. This corresponds to the amount that a local resident would receive from natural radiation in a few hours. In the eastern Uusimaa, natural radon concentrations are high due to the granitic rock and soil.

Radiation dose and dose rate

The radiation dose describes the health damage caused by radiation. It is often expressed in thousandths of a sievert, or millisieverts (mSv), or parts per million, or microsieverts (µSv).

The dose rate indicates the dose a person receives in a given time. The unit of dose rate is sieverts per hour (Sv/h).

Some examples of radiation doses

Dose rateWhat the rate causes
0,01 mSvThe radiation dose received by a patient having his/her teeth X-rayed.
0,1 mSvThe radiation dose received by a patient having his/her lungs X-rayed.
2 mSvThe annual dose of cosmic radiation received by a person working in an aeroplane.
3,2 mSvThe average annual radiation dose for Finns caused by indoor radon, X-ray examinations, etc.
20 mSvThe highest permitted dose for a radiation worker over a period of a year.
1000 mSvThe dose which may cause symptoms of a radiation sickness (e.g. tiredness and nausea) if received within 24 hours.
6000 mSvA dose that when received within under 24 hours causes radiation sickness and can be fatal.

 

Some examples of external dose rates

Dose rateExample
0,04–0,30 µSv/hNatural background radiation in Finland.
0,2–0,4 µSv/hThe dose rate which, if it's exceeded, causes an alarm in an automatic radiation monitoring station in the Finnish automatic external dose rate monitoring network. Each station in Finland has its own station-specific alarm level, which is determined separately for each station. Alarm levels in Finland are between 0.2 and 0.4 µSv/h. The differences are mainly caused bu the level of natural radioactivity in the soil surrounding each sensor.
5 µSv/hThe dose rate in an aeroplane flying at an altitude of 12 kilometres.
5 µSv/hThe highest dose rate measured in Finland during Chernobyl accident.
10 µSv/hSome protective measures are needed, e.g. avoiding being outdoors unnecessarily.
30 µSv/hThe dose rate measured at a distance of one metre from a patient that has undergone isotope treatment. When the dose rate is less than 30 µSv/h, the patient can be discharged.
100 µSv/hIt is necessary to take protective measures, e.g. to shelter indoors.
Source: STUK.fi 

 

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