STP676: In-Reactor Stress Relaxation of Type 348 Stainless Steel In-Pile Tube

    Beeston, JM
    Senior scientist and supervisor, EG&G Idaho, Inc., Idaho Falls, Idaho

    Burr, TK
    Senior scientist and supervisor, EG&G Idaho, Inc., Idaho Falls, Idaho

    Pages: 16    Published: Jan 1979


    Abstract

    The results of a slit tube test, which show that large residual stresses do not develop during irradiation of in-pile tubes at operating temperatures of 573 to 698 K are presented. The slit width measurement at ambient conditions indicates that the predicted stress gradient due to irradiation growth was completely relaxed, and the residual stress that opened the slit was caused by the tube wall temperature change (hot to cold) when the reactor was shut down. No voids were detected and no immersion density gradient or difference in transmission electron microscopic (TEM) observations of irradiation-produced defects was found through the wall thickness. The microstructural mechanism for plastic flow through irradiation creep could explain the relief of the differential swelling stresses.

    Keywords:

    stress relaxation, irradiated stainless steel, density, irradiation-produced defects, temperature range, slit width measurement, irradiation creep, irradiation swelling


    Paper ID: STP37422S

    Committee/Subcommittee: E28.11

    DOI: 10.1520/STP37422S


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