Session: CS-08-02 The Warren H. Bamford Memorial Symposium on Recent Developments in ASME Codes and Standards: ASME Code Section XI Activities-2

Paper Number: 155330

155330 - Crack Growth Evaluation of Nozzle Corner Cracks Using the Jsme Code Case and Existing Solutions 

Abstract: 

Fatigue crack growth analysis results were compared to validate the JSME Code Case which provides analytical solutions for nozzle corner cracks. The JSME Fitness-for-Service (FFS) Code requires structural integrity evaluation when cracks are detected at nozzle corner. However, stress intensity factor (SIF) solution for nozzle corner cracks was not provided in the JSME FFS Code. SIF solution for nozzle corner cracks was investigated by finite element analysis using 3-D models and existing SIF solutions. An appropriate and conservative approach was selected based on comparisons of SIF results. The JSME proposed a unique approach to calculate SIF of nozzle corner cracks which employes flat plate solutions provided in the current FFS Code combined with crack characterization. In the crack characterization, quarter-circle crack at nozzle corner is characterized as a semi-elliptical crack in a flat plate. Crack sizes and thickness of a flat plate are determined by the corner crack sizes and nozzle/shell geometries. The Case provides SIF solutions for nozzle with quarter-circle corner crack subjected to internal pressure and enable analytical evaluation for fatigue. Effect of SIF solutions on fatigue crack growth analysis was investigated by comparison of the analysis results using the Case and existing solutions. As a result, the Case solution is almost the same as existing solutions or conservative.

Presenting Author: Fuminori Iwamatsu Hitachi, Ltd.

Presenting Author Biography: In March 2006, the author completed master's course in Graduate School of Engineering, Yokohama National University.
In April of the same year, he joined Hitachi, Ltd., Hitachi Research Laboratory.
He is now engaged in research and development on structural integrity of nuclear power plants.

Authors:

Fuminori Iwamatsu Hitachi, Ltd.
Teppei Kubota Hitachi-GE Nuclear Energy, Ltd.