STP1490

    Retrospective Dosimetry of Fast Neutrons Focused on the Reactions 93Nb(n,n')93Nbm and 54Fe(n,p)54Mn

    Published: Jan 2007


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    Abstract

    An overview is given of practices for “retrospective” dosimetry based on extraction and counting of niobium and manganese present in typical pressure vessel materials. The main problem of counting structural materials is the overwhelming presence of the nuclide 60Co in the gamma-ray spectra of irradiated materials. Chemical separation of niobium and manganese is needed to determine the induced 93Nbm and 54Mn activities. Procedures have been developed for retrospective dosimetry applicable at normally equipped radiochemical laboratories. Chemical separation procedures have been applied followed by determination of the amount of niobium in dissolution after separation. Special attention has been given to the accurate counting of the very weak X rays of 93Nbm. Different techniques have been applied. Advantages, disadvantages, and the accuracy that can be achieved are discussed. Special attention has been given to the maximum accuracy that can be reached and the minimum amount of niobium that has to be collected to reach this accuracy.

    Keywords:

    retrospective dosimetry, neutron fluence, neutron damage, niobium, manganese, column anion exchange, liquid scintillation counting, neutron activation analysis


    Author Information:

    Voorbraak, W. P.
    MMI-Monitoring, Netherlands Research and Consultancy Group NRG, Petten,

    Kekki, T.
    VTT Technical Research Centre of Finland,

    Serén, T.
    VTT Technical Research Centre of Finland,

    Van Bockxstaele, M.
    SCK-CEN, Mol,

    Wagemans, J.
    SCK-CEN, Reactor Physics & Myrrha Department, Mol,

    Woittiez, J. R. W.
    Medical Applications, Netherlands Research and Consultancy Group NRG, Petten,


    Paper ID: STP45470S

    Committee/Subcommittee: E10.08

    DOI: 10.1520/STP45470S


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