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In accordance with a decision of the Radiation and Nuclear Safety Authority, the following provisions are issued by virtue of section 59, subsection 2 and section 63, subsection 3 of the Radiation Act (859/2018):

This regulation applies to the measurements of ionizing radiation carried out under the Radiation Act.

In rescue operations and civil defense referred to in the Rescue Act (379/2011), this regulation applies to radiation measurements with portable meters.

For the purposes of this regulation, the following terms have the following meanings:

1. measuring instrument means a radiation meter measuring external radiation other than a contamination meter, and which is calibrated or the calibration of which is checked by means of a reference instrument;
2. expanded uncertainty of measurement means the product of combined uncertainty of measurement and coverage factor;
3. uncertainty of measurement means a quantitative assessment of the quality of the measurement result that describes the presumed variation in the values of the measured quantity;
4. measurement system means a system intended for measurements, comprising radiation meters, radiation detectors, a reader or readers, peripheral equipment and computer programs and operating instructions;
5. reference conditions mean the radiation type and radiation quality stated in the standard pertaining to the measuring instrument and the stated environmental conditions where the reference values have been defined;
6. intrinsic error means a defined error in reference conditions;
7. radiation quality means the energy distribution of a radiation type;
8. radiation type means the physical form of radiation;
9. reference instrument means a measuring instrument that is calibrated using measurement standards;
10. error means the difference between a measurement result and the correct value of the measured quantity after all the known corrections have been made;
11. environmental conditions mean conditions other than those resulting from ionizing radiation that may affect the measurement result.

The following shall be used in measurements:

1. the base units set out in the Government Decree on Units of Measurement (1015/2014) and other SI units;
2. the quantities and measurement units used in the determination of radiation exposure set out in the Government Decree on Ionizing Radiation (1034/2018);
3. the quantities and measurement units defined in Annex 2.

The radiation meter shall be suitable for the measurement with the values, radiation types and radiation qualities of the quantity being measured. If the dose rate of the radiation being measured is pulsed, the measuring instrument and the measuring system shall be capable of measuring both continuous and pulsed radiation. Additionally, the radiation meter shall be suitable for the environmental conditions prevailing in its place of use.

The metrological traceability of a measurement result shall be demonstratable based on the information provided in the calibration certificate of the measuring instrument and measurement system and the description of the method of measurement used.

To demonstrate the metrological traceability of the measuring result of the measuring instrument, the calibration data referred to in section 14 may be provided in the data of the user’s management system instead of a calibration certificate.

An uncertainty assessment shall be conducted on the measurement results of measurements concerning radiation practices and radon concentration measurements of a workplace, dwelling or other premise used by people.

The reliability, measuring instrument and measurement system of radiation measurements shall meet the requirements specified in Annex 1, Tables 1.1—1.3.

The measurement quantities set out in Annex 1, Table 1.1 and 1.3 shall be used in radiation measurements conducted for radiological surveillance and individual monitoring and in radiation measurements conducted to ensure the safety of population.

In radiation measurements conducted for radiological surveillance and public exposure, the effect of radiation on the response of the radiation meter shall be known.

If the dose rate in the measurements referred to in subsection 1 may exceed the operating range of the meter, the meter shall in such cases indicate overloading.

When the accuracy of the dosimetry system used for determining the individual dose of a radiation worker is determined, the radiation type and quality, variation range of dose rate and dose as well as the pulsed form of the radiation shall be taken into account.

In determining the dose from internal exposure, activity measurements must consider the nuclides to be measured.

Specifications shall be available of the characteristics and performance of the dosimetry system intended for individual monitoring, including test results on the dependency of the response of the dosemeter on the measured dose, radiation energy and energy distribution, the direction of radiation, the detection threshold of the measurement system and the effect of environmental conditions on the measurement result.

The dosimetry system intended for individual monitoring and the meters included in it shall be capable of measuring the personal dose equivalent H_p(d).

Specifications shall be available of the characteristics and performance of the measurement system used for determining occupational and internal public exposure, and with regard to the test results, reference shall be made to the standards used for demonstrating the reliability of the measurements, or a description of the testing method shall be provided. When the dose arising from internal exposure is determined, the time of the exposure, the ways of exposure, the absorption class, the particle size and any prior exposure shall be taken into account.

A portable dose rate meter used in rescue operations and civil defence shall have a continuously operating audio signal for detecting the dose rate and any changes in it. The measuring instrument shall be provided with instructions for use. The power source used in the measuring instrument shall be of a commonly used type.

A meter for measuring radon concentration and radon-induced exposure shall be a reference instrument.

Specifications shall be available of the characteristics and performance of the meter and the measuring system for measuring radon concentration and radon-induced exposure. With regard to the test results, reference shall be made to the standards used for demonstrating the reliability of the measurements, or a description of the testing method shall be provided.

When the medical exposure in X-ray examinations and procedures and in external radiotherapy and brachytherapy is measured, the measurement quantities set out in Annex 1, Table 1.2 shall be used.

If a quantity other than that referred to in subsection 1 is used in the display of an instrument used in X-ray examinations and procedures, the operator shall know the relationship of this quantity to the quantity referred to in section 1 and the metrological traceability of the measurement results.

The requirements of sections 13 and 15(4) shall apply to any computational displays used for determining medical exposure in X-ray examinations and procedures.

In nuclear medicine examinations and treatment, the measured quantity in the measurement of the radiopharmaceutical shall be activity.

The intrinsic error of the measurement may not exceed 10% with activity in excess of 3.7 MBq. When the activity is not more than 3.7 MBq, the intrinsic error may be higher than 10%, but its highest possible value shall be estimated. If the radioactive substance being measured has daughter isotopes whose activity is measured and that are not in equilibrium with their parent nuclides, the effect of this in the measurement result shall be taken into account.

The deviation of an individual measurement result from the average of the results in a series of ten measurements may not exceed 5%. The activity used in the measurement shall be the activity of a typical radiopharmaceutical administered to a single patient.

If the activity meter is used for measuring gamma radiation with energy not exceeding 100 keV, beta radiation or alpha radiation, the effect of the ampoule and the measurement geometry on the measurement result shall be taken into account.

The linearity deviation of the response of the activity meter may not exceed 5% with an activity not exceeding 5 GBq. The linearity of the response of the activity meter shall be measured with at least one radionuclide. With activity in excess of 5 GBq, the activity meter shall be calibrated with the activity used.

The radiation meter and the measuring system shall be calibrated prior to their commissioning.

The radiation meter and the measuring system shall be calibrated based on an applicable standard. If there is no such standard, the calibration shall be carried out using other standardized methods and international good practices.

By way of derogation from the calibration requirements set out in subsection 2 of this section, the calibration of a measuring instrument may be based on a procedure which is in accordance with the general calibration principles.

The dosimetry system used for individual monitoring and the reference instruments for radiation practices and rescue operations shall be calibrated by a laboratory accredited for calibrations of radiation meters or a national metrological laboratory.

The meter and the measurement system used for determining radon concentration in the air and radon-induced exposure shall be calibrated by laboratory accredited for radon concentration measurements.

The presentation of the calibration results shall meet the requirements of ISO/IEC 17025 for calibration and testing laboratories and the specific requirements for a calibration laboratory. However, the calibration results of a radiation meter that is only used as a measuring instrument can be limited to only include the calibration procedure, the calibration quantity, the numerical result and its unit and uncertainty.

Measuring instruments shall be calibrated using a reference instrument.

The operation of a portable radiation meter used for rescue operations, civil defence or radiological surveillance can be checked by means of a radiation source and a reference instrument instead of calibration.

The calibration interval of a reference instrument, measuring instrument and measurement system may not exceed five years, unless otherwise provided below or otherwise decided by the Radiation and Nuclear Safety Authority when approving the method of measurement or practice or otherwise.

The calibration interval of a meter or measurement system for radon concentration in air or radon-induced exposure may not exceed two years.

In external radiotherapy, the calibration interval of radiation meters used for the dose calibration of radiotherapy equipment, and in brachytherapy, calibration interval of radiation sources and radiation meters used for the calibration of radiation sources may not exceed three years.

The calibration interval of a measuring instrument used for measuring medical exposure may not exceed two years.

A radiation meter shall be in an operating condition. The operating condition shall be verified by means of testing.

The operation of a radiation meter shall be tested at regular intervals using a suitable radiation source or reference instrument. Additionally, the operation shall be tested whenever there is a reason to suspect changes to the operating condition of the meter.

The operation of a radiation meter shall be tested under known and reproducible radiation conditions. The measurement results obtained shall be compared against the radiation values known based on similar measurements previously conducted, and the meter shall be recalibrated if necessary.

The alarm functionalities in the radiation meter shall be tested.

This regulation enters into force on 1 May 2021 and it will be valid until further notice.

This regulation applies to any matters pending on the date of its entry into force.

This regulation repeals the Radiation and Nuclear Safety Authority’s Regulation on Radiation Measurements (STUK S/6/2018).

In Helsinki on 27 April 2021

Annexes 1 and 2

Council Directive 2013/59/Euratom (32013L0059); OJEU L 13, 17.1.2014, p. 1
Reported to the Commission in accordance with Article 33 of the Treaty establishing the European Atomic Energy Community.