<p style="margin: 0mm">The seismic probabilistic risk assessment is an important methodology to evaluate the seismic safety of nuclear power plants. In the assessment, the core damage frequency is evaluated by using the seismic fragilities, seismic hazard, and accident sequence. When the age-related degradation due to the long-term operation of nuclear power plants is unneglectable, it is required to consider the changes in seismic response characteristics and the deterioration of strength during the seismic fragility evaluation. The probabilistic fracture mechanics can be applied as a useful evaluation technique for aged piping with crack or wall thinning due to the age-related degradation, in the seismic fragility evaluation. Here, to advance seismic fragility evaluation methodology for the long-term operated nuclear power plants, a probabilistic fracture mechanics analysis code PASCAL-SP has been developed and a guideline for the seismic fragility evaluation on the typical aged piping of nuclear power plants has been completed, taking the aged-related degradation into account, in our JAEA. The guideline consists of a main body and a supplement. The evaluation procedure, key points of evaluation, recommendation models and methods are provided in the main body. The technical bases for the recommendation, the typical analysis conditions and analysis results are provided in the supplement. The fragility evaluation for aged piping can be conducted by referring to the guideline. In this paper, the outline of the guideline is explained and some evaluation examples based on the guideline utilizing PASCAL-SP are presented.</p>

Development of Guideline on Seismic Fragility Evaluation for Aged Piping

Paper Proceedings: https://asmedigitalcollection.asme.org/PVP/PVP2021/volume/85314

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