STP754: Long-Term Test Results of Promising New Zirconium Alloys

    Castaldelli, L
    Metallurgist and senior metallurgist, Comitato Nazionale per l'Energia Nucleare, Rome,

    Fizzotti, C
    Metallurgist and senior metallurgist, Comitato Nazionale per l'Energia Nucleare, Rome,

    Lunde, L
    Metallurgist, Institute for Energy Technology, Kjeller,

    Pages: 22    Published: Jan 1982


    Abstract

    A series of new alloys has been long-term tested in different reactors and environments together with other alloys, including Zr-2.5Nb, Ozhennite 0.5, and Zircaloy-2. One of the new alloys with the composition of Zr-1Nb-1Sn-0.5Fe has significantly improved properties.

    The zirconium-niobium alloys have corrosion properties similar to Zircaloy-2 in the temperature range 240 to 400°C while they are better at 450°C and above. Conditions leading to nodular corrosion in Zircaloy-2 did not produce nodular attack on the Zr-1Nb-1Sn-0.5Fe alloy, or on Zr-2.5Nb. The niobium-containing alloys fail to suffer intergranular cracking in iodine-methanol solution even when stressed to 80 percent of their yield strength for more than 60 days. The other alloys failed at 30 percent of yield strength in a few hours. Preliminary iodine-argon iodine-pressurized burst tests indicate some improvement for the Zr-1Nb-1Sn-0.5Fe alloy compared with Zircaloy-2 with a five to ten times increase in time to failure for the same stress level.

    Elongation was markedly reduced by irradiation in all the alloys. Uniform elongations of about 1 percent were observed in the 2.5Nb alloy while the highest uniform elongation of 2 to 3 percent was shown by the Zr-1Nb-1Sn-0.5Fe alloy.

    Keywords:

    zirconium, nuclear industry, zirconium alloys, corrosion, mechanical properties, irradiation, reactors


    Paper ID: STP37050S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP37050S


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