STP1547: Material Investigations on Highly Irradiated Aluminum Magnesium Alloys for Lifetime Assessment of a Neutron Beam Tube in the BER II Research Reactor

    Hein, Hieronymus
    AREVA NP GmbH, Erlangen,

    Schnabel, Hilmar
    AREVA NP GmbH, Erlangen,

    Welzel, Stephan
    Helmholtz Zentrum Berlin, Berlin,

    Pages: 19    Published: Jan 2013


    Abstract

    For the research reactor BER II operated in Berlin, Germany material investigations on irradiated and unirradiated AlMg3 specimens were performed in order to assess the allowable operation time of a conic neutron beam tube. For this purpose, tensile specimens have been manufactured from archived material and from a highly irradiated decommissioned component of the same material. The uniform elongations obtained in this way were used for the proof of the remaining ductility of the neutron beam tube with respect to the neutron fluence accumulated. The irradiation history, the essential steps of the neutron fluence determination, of the manufacturing process and of the testing procedure are described. The results of the tensile tests are discussed in detail and with respect to the remaining lifetime of the component. The measured tensile data shows reasonable agreement with existing test data for similar materials and comparable conditions. Below the designed end of life fluence of 1 × 1022 n/cm2 (E > 0.1 MeV) a uniform elongation of at least 5 % was confirmed which is the minimum to ensure sufficient ductility during operation.

    It can be concluded that the use of representative material from decommissioned components is an appropriate measure to monitor the irradiation behavior of research reactor components made by aluminum magnesia alloy. Finally, an approach for fracture toughness testing is introduced in order to complement tensile testing in dedicated surveillance programs for research reactors.

    Keywords:

    aluminum magnesium alloys, irradiation embrittlement, neutron irradiation, research reactor


    Paper ID: STP104128

    Committee/Subcommittee: E10.02

    DOI: 10.1520/STP104128


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