An Alternative Non-Destructive Method for Evaluating the Remaining Service Life of Thermal and Nuclear Power Plants: Miniaturized-Specimen Creep Testing

Creep is the main degradation mechanism in steels operating at high temperatures in thermal and nuclear units, like reheater, heater and main steam line. For a realistic calculation of the remaining useful life of these units is essential to obtain creep data from the materials in operation. However, in many applications, there are severe limitations to obtain sufficient material for the fabrication of standard size specimens. The use of smaller specimens for creep tests may come as an important tool for the assessment of power plant components, since the removal of a limited amount of material does not cause structural damage. The objective of this article is to compare creep test results of a CrMo ferritic steel using specimens with conventional, reduced sizes and small punch creep test (SPC) specimens, in order to assess the effectiveness of these alternatives. The results showed that the use of miniaturized specimens for creep tests yields a reliable monitoring technique for the equipment's remaining life, and, ultimately, the life of the power plant, whether thermal or nuclear.