Individual electronic neutron dosimetry in workplaces of the French and European power plants and fuel processing facilities
T. Lahaye, Q. Chau, S. Ménard, T. Bolognese-Milsztajn, V. Lacoste, IRPA 24-28 mai 2004, Madrid, Espagne.
Despite a widely recognised need, electronic devices for personal dosimetry in neutrons or mixed neutron-photon fields are still far less established than systems for photons alone. The workers of the nuclear installations are mainly exposed to neutron fields with energy varying on more than eight decades. The European inter-comparison carried out by EURADOS at the end of the 90ies clearly showed that the performances of the current passive dosemeters used for routine monitoring are still not completely satisfactory.
The development of electronic neutron dosemeters was necessary to comply with the European directive 96/29 and to provide a better radiation monitoring of the nuclear industry workers.
Hence, the Institute for Radiological Protection and Nuclear Safety (IRSN) has developed the “Saphydose-n” dosemeter, an electronic personal dosemter based on a silicon detector. This new EPD has some spectrometric capabilities since the Si detector is divided into four cells made of various type of materials. More than eight neutron energy decades are covered then evaluated in broad intervals. This method leads to a constant neutron energy response of the dosemeter. It is then suitable for any nuclear facility without prior knowledge of the neutron spectrum or the neutron-gamma ratio. Furthermore, this dosemeter complies with the recommendations of the IEC 1323 standards. During the last two years, the Saphydose-n dosemeter was tested in several nuclear installations (French and European) and its readings were compared to other individual electronic devices.
In this paper, the main characteristics of Saphydose-n as well as the measurements and results obtained with individual neutron dosemeters in different representative workplaces in France and in Europe are presented. IRSN participates to the EVIDOS program research funded by EC (“Evaluation of Individual Dosimetry in Mixed Neutron and Photon Radiation Fields”) intended to provide significant improvements by spectrometric and dosimetric investigations in representative neutron/photon workplaces in the nuclear industry.
In this framework the results of the Saphydose-n will be compared with reference values derived from spectrometric systems.