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Verification of licensee's monitoring of radioactive effluents from nuclear installations

  • The BfS verifies the reliability and quality of the licensee’s monitoring of radioactive effluents by operators of nuclear installations.
  • Key instruments for quality assurance are a control measurement programme and proficiency tests. It is mandatory for the operators of nuclear installations or for their contracted measurement laboratories to participate in these proficiency tests.

For more than 30 years, the Federal Office for Radiation Protection (BfS) and its predecessor authority respectively, have been verifying the reliability and quality of the licensee’s monitoring of radioactive effluents by operatorsof nuclear installations.

Exemplary analysis result of the  proficiency test "waste water" in 2022 Interlaboratory comparison waste waterExample: Analysis result of the proficiency test "waste water" in 2022

Instruments for quality assurance

Key instruments for quality assurance are a control measurement programme and proficiency tests. To this end, the BfS carries out random control measurements according to § 103 (4) Radiation Protection Ordinance.

Control measurement programme

All samples used for assessment are submitted to the BfS by the operators. The BfS selects randomly selects samples among those submitted samples according to the guideline "Verification of the Licensee's Monitoring of Radioactive Effluents from Nuclear Power Plants", (see table) and carries out its own activity determinations.

Monitoring the emissions of a nuclear power plant:
Annual control measurement programme exhaust air / waste water
Radionuclide / radionuclide groupFrequency and type of control measurement for each nuclear power plant
Exhaust air-
gamma emitters10 per cent of the weekly samples
iodine isotopes10 per cent of the weekly samples
strontium isotopes4 quarterly mixed samples
alpha emitters4 quarterly mixed samples
carbon-14at least 1 quarterly mixed sample
tritiumat least 1 quarterly mixed sample
radioactive noble gaseson-site comparative measurements every three years
Waste water-
gamma emitters8 - 9 weekly mixed samples
strontium isotopes1 quarterly mixed sample
total alpha1 quarterly mixed sample
tritium1 quarterly mixed sample
iron-55 / nickel-631 annual mixed sample

Exhaust air sample Exhaust air sampleExhaust air sample

Proficiency Tests

Supported by the Physikalisch-Technische Bundesanstalt (PTB, National Metrology Institute of Germany), the BfS organises an annual

  • proficiency test "exhaust air" for measuring the activity of selected radionuclides on standard filter preparations as well as (see figure "exhaust air sample prepared for measurement")
  • proficiency test "waste water" for determining the radionuclide composition of a model waste water sample from a nuclear installation (see figure "waste water samples prepared for interlaboratory comparison measurements").

Waste water samples for proficiency test measurements Waste water samplesWaste water samples prepared for proficiency test measurements

Additionally, proficiency tests for tritium and carbon-14 on molecular sieve samples are carried out in irregular intervals in the field of “exhaust air”.

It is mandatory for the operators of nuclear installations or for their contracted measurement laboratories to participate in these proficiency tests.

The proficiency tests allow for the objective evaluation of the quality of the measurement values determined in the framework of licensee's monitoring.

In recent years, the participation of international measurement laboratories has increased.

If you are interested in the proficiency test of the BfS, you can register by e-mail:

Expert talks

Expert talks in the fields of "exhaust air" and "waste water" are held regularly by the BfS. The operators of nuclear installations and the competent supervisory authorities participate in the talks.

At the talks, the BfS provides information on current problems identified during control measurements or proficiency tests and discusses them in the plenary. Furthermore, expert talks are a significant contribution to communicating the state of the art of science and technology in the field of emission monitoring.

State of 2023.06.19

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