STP939: Development of a Sensitive and Reproducible Steam Test for Zircaloy Nodular Corrosion

    Cheng, B
    Principal Engineer and Manager, General Electric Company, Pleasanton, CA

    Levin, HA
    Principal Engineer and Senior Program Manager, Fuel Design and Development, Nuclear Fuel Engineering Department, San Jose, CA

    Adamson, RB
    Principal Engineer and Manager, General Electric Company, Pleasanton, CA

    Marlowe, MO
    Principal Engineer and Senior Program Manager, Fuel Design and Development, Nuclear Fuel Engineering Department, San Jose, CA

    Monroe, VL
    Manager, Equipment and Component Quality, GE Wilmington Fuel Manufacturing Department, Wilmington, NC

    Pages: 25    Published: Jan 1987


    Abstract

    The sensitivity and reproducibility of high-temperature, high-pressure steam tests for Zircaloy nodular corrosion were studied as a function of test parameters, such as temperature, pressure, test duration, and flow rate, using a recirculating autoclave loop. Other variables, such as heat-up rate and oxygen and hydrogen gas contents, were also studied.

    The effects of the test variables and gaseous species on test reproducibility are minimized by the addition of a prefilming step at 410°C for 4 to 8 h before exposing the test samples to a higher nodule-forming temperature. The prefilming treatment reduces the degree of nodular corrosion, but the reduced nodule sensitivity can be regained by controlling the second-step test temperature. A test involving a prefilming step at 410°C/1500 psig (102 bars) for 8 h and a nodule sensitivity step at 510°C/1500 psig (102 bars) for 16 h has been found to be capable of reproducibly discriminating Zircaloy cladding source materials into a broad spectrum of nodular corrosion susceptibility. Good reproducibility of the 410/510°C two-step test was demonstrated over 40 test runs using control samples. The two-step test was calibrated to in-reactor corrosion performance using pretested samples and irradiated plenum samples removed from fuel rods.

    Keywords:

    Zircaloy, nodular corrosion, steam test, in-reactor corrosion, test reproducibility


    Paper ID: STP28124S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP28124S


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