Description: Das Projekt "Verbesserung passiver und aktiver Neutronennachweisverfahren fuer die Charakterisierung von Gebinden fuer radioaktive Abfaelle" wird vom Umweltbundesamt gefördert und von Physikalisch-Technische Bundesanstalt durchgeführt. The final storage of radioactive waste containers requires their compliance with given waste acceptance criteria. For this reason, appropriate quality control procedures have to be carried out to determine various physical and chemical parameters of die waste form and to identify and quantify all relevant radioactive isotopes present in die container. Within these procedures, preferably non-destructive techniques are used in order to minimise inspection time and to avoid unnecessary secondary waste by invasive sampling and subsequent chemical and radiochemical preparation, separation and analysis of the obtained material. The characterisation of neutron emitting nuclides and fissile material can be performed best with passive and active neutron assay techniques. While these methods have been used in safeguarding successfuelly, in waste monitoring precise measurements are difficult due to the usually unknown and inhomogeneous matrices and die random localisation of the emitters in the bulk of these matrices. These problems are still present, although passive neutron counting and active neutron interrogation devices are commercially available, respectively. The main objective of the project is die improvement of localisation and quantification of neutron emitters due to spontaneous fission (sf), (a, n)-reactions and induced fission within typical waste packages. These comprise drums ranging from 200 1 up to 500 1 filled with different (inhomogeneous) matrices with densities ranging from ca. 0,5 g/cm3 up to ca. 3,0 g/cm3. Within die first work package of the project the characterisation of sf- and (a,n)-emitters by passive neutron counting is investigated thoroughly. This includes the study of the applicability of time correlation methods (TCM) for the distinction between sf- and (a,n)-emitters for typical waste matrices and the development of the basics for die improved localisation and quantification of neutron emitters resulting in a general algorithm. Commercially available active neutron interrogation devices do not provide sufficient information from measurements to characterise die waste packages with respect to their neutron moderation and absorption characteristics. Using these devices complex calibration procedures for each waste form are needed. The classification of waste packages by a low number of calibrations is very problematic due to die heterogeneity of the waste. Therefore, die measurement accuracy for die quantification of fissile is decreased. To overcome this well known matrix problems the properties of existing neutron sources and advanced detector configurations have to be considered.
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Neutronenstrahlung ? Abfallvermeidung ? Kalibrierung ? Radioaktiver Abfall ? Sensor ? Sperrmüll ? Main ? Endlagerung radioaktiver Abfälle ? Aufbereitungstechnik ? Radionuklid ? Strahlungsmessung ? Transportbehälter ? Qualitätsmanagement ? Abfall ? Abfallbehälter ? Chemikalien ? Messverfahren ? Studie ? Abfalleinstufung ? Verpackung ? Abfallgebinde ? Aktiver-Neutronennachweis ? Nachweisverfahren ? Neutronen ? Passiver-Neutronennachweis ?
Region: Lower Saxony
Bounding box: 9.16667° .. 9.16667° x 52.83333° .. 52.83333°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 1996-02-01 - 1999-01-31
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