Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: Creep-fatigue assessment of a thermina test specimen using the R5 procedure

Abstract

A creep-fatigue life assessment of an axisymmetric 316 stainless steel test specimen under constant mechanical and cyclic thermal shock loading using the R5 Procedure is described in this paper. This test was carried out at CEA, France, and formed part of the 'Thermina' series. Stress analysis has been carried out using both full inelastic finite element analysis and also the simplified shakedown methods, based on elastic calculation, within R5. The estimates of strain range and the stress at the start of the creep dwell have then been used with R5 to estimate creep and fatigue damage per cycle and hence to make predictions of component life. The predicted lives are compared with the lives observed in the tests. The simplified R5 estimate of life, based on development of a crack of depth 200 microns, is 260 cycles using best-estimate material properties. Experimentally, cracks of depth at least 150 microns were observed in between 526 and 650 cycles, for two similar tests. The simplified R5 route therefore leads to an estimate of life which is conservative but not unduly so on this component. Detailed cyclic inelastic analysis using the ORNL constitutive model and the ABAQUS finite element code to estimate the strain range and dwell stress led to a best estimate of 618 cycles to crack initiation using R5.

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Reference:

Creep-fatigue damage rules for advanced fast reactor design. Technical committee meeting, Manchester (United Kingdom). 11-13 Jun 1996

International Atomic Energy Agency, Vienna (Austria)

IAEA-TECDOC--933, pp:261-279