Reactor dosimetry

The Nuclear Systems Measurements unit provides neutron reactor dosimetry services. This includes following activities:

  • Determination of the neutron induced gamma- (or X-ray) activity of dosimeters or samples.
  • Determination of the neutron flux and fluence at the dosimeter or sample position.
  • Design and composition of neutron dosimetry sets for experiments and for reactor pressure vessel surveillance programmes.
  • Irradiations in neutron standard fields in the BR1 reactor.
  • Consultancy and services for retrospective reactor dosimetry and for research and reactor experiments.

Dosimetry tubes prepared for an ex-vessel irradiation at a nuclear power plant
 
Typical dosimetry sets: wire dosimeters to be inserted in stainless steel tube (top) and two sets of foils to be inserted in a Cd or Al box

SCK•CEN and the reactor dosimetry group in particular is actively involved in the European Working Group on Reactor Dosimetry.

Quality Assurance

The SCK•CEN reactor dosimetry service has been accredited by BELAC (Ministry of Economic Affairs) under the accreditation number 015-TEST, norms NBN EN ISO/IEC 17025, for the following measurements:

Standard

Test

ASTM E181

Standard Test Methods for Detector Calibration and Analysis of Radionuclides

ASTM E261

Standard Practice for Determining Neutron Fluence Rate, Fluence, and Spectra by Radioactivation Techniques

ASTM E262

Standard Test Method for Determining Thermal Neutron Reaction and Fluence Rates by Radioactivation Techniques

ASTM E263

Standard Test Methods for Measuring Fast-Neutron Reaction Rates by Radioactivation of Iron

ASTM E264

Standard Test Methods for Measuring Fast-Neutron Reaction Rates by Radioactivation of Nickel

ASTM E523

Standard Test Methods for Measuring Fast-Neutron Reaction Rates by Radioactivation of Copper

ASTM E526

Standard Test Methods for Measuring Fast-Neutron Reaction Rates by Radioactivation of Titanium

ASTM E704

Standard Test Methods for Measuring Reaction Rates by Radioactivation of Uranium-238

ASTM E705

Standard Test Methods for Measuring Reaction Rates by Radioactivation of Neptunium-237

ASTM E1005

Standard Test Method for Application and Analysis of Radiometric Monitors for Reactor Vessel Surveillance

ASTM E1297

Standard Test Methods for Measuring Fast-Neutron Reaction Rates by Radioactivation of Niobium

Our equipment

The reactor dosimetry laboratory is equipped with six hyper-pure germanium detectors at which sample activities ranging from 102 Bq up to 108 Bq can be measured. One of these systems is exclusively used for the detection of X-rays.


Typical germanium detection system

In order to increase the laboratory efficiency, a fully automated detection system has been developed. This is a stand-alone system operated with in-house developed, validated software and has a sample changer in which up to thirty dosimeters can be loaded.

The measurement data are converted to activities, neutron fluxes and fluences using Excel worksheets and in-house developed software taking into account irradiation history and material burn-up corrections.


Drawing of the automated detection system

In addition to the six germanium detectors, the laboratory is equipped with:

  • a glove box
  • a fume hood
  • precision balances
  • a separate dosimeter preparation and weighing room


Precision balance for the dosimeter mass determination

Contact: Jan Wagemans