Session: SE-09-02 Advanced Seismic Evaluation and Code - 2

Paper Number: 107197

107197 - Elastic-Plastic Analysis for Crossover Piping by Using ASME Code Case N-900 and JSME Code Case NC-CC-008 

　In 2019, two remarkable code cases （ASME CC-N900/JSME NC-CC-008） regarding  seismic design method by elastic-plastic analysis were published by ASME/JSME almost simultaneously. However, there are few practical applications by both code cases in actual seismic design work.

The initial edition of N900 was developed so that it had additional conservatism until additional supporting test data is available and can be reviewed. ASME CC-N900 has some technical issues to be addressed such as limitation to usage factor, constitutive equation of materials, limitation to fabrication strain of pipe fittings and tri-axiality factor.

Also, ASME code case provides limitation to the fatigue with progressive ratcheting deformation, based on the assumption that piping failure due to maximum response displacement for one SSE level ground motion, which the equivalent seismic cycle number, is 10 cycles occurs and fatigue failure don't occur because the damping of piping is large and response displacement rapidly decrease in a short time.

However, in case of seismic design of crossover piping across the building isolation boundary, which are supported at many points, the seismic design of crossover has the antimony issues that it’s necessary to resolve overstressed piping due to both large seismic anchor movements and large seismic inertia forces. It’s difficult to resolve this issues and perform the rational seismic design by current ASME code cases.

 This report provides the technical topics regarding specific seismic design rules for crossover piping across the building isolation boundary, based on design example of large bore crossover piping by both code case（ASME CC-N900/JSME NC-CC-008）.

Presenting Author: Kenichi Shibukuwa IHI Corporation

Presenting Author Biography: Kenichi Shibukuwa is a manager at IHI Corporation in Japan. His work focuses specifically on management of maintenance and construction project for Domestic Nuclear Power Plant. He has a lot of expertises in the piping engineering of nuclear power plant for 33 years. Also, He has been active in JSME(The Japan Society of Mechanical Engineers) and JEA(The Japan Electric Association) as code engineer since 2020.

Authors:

Kenichi Shibukuwa IHI Corporation