Session: CS-12-01 High Temperature Codes and Standards

Paper Number: 105722

105722 - Comparison of Ratcheting Results Using Available Methodologies in Asme Iii Division 5 

While conventional nuclear reactors have solid fuel rods that need constant cooling, typically using water at around 300°C under high pressures. In Seaborg’s Compact Molten Salt Reactor, fuel is mixed in a liquid salt that also acts as a coolant.

This ensures the fuel can always be cooled and cannot melt down or explode. For this to happen, the reactor must operate at much higher temperatures and low pressures. Combined with long operating times, these conditions require evaluating specific failure modes, such as accumulation of inelastic strain or ratcheting, creep-fatigue damage interaction, and time-dependent buckling.

Specifically for ratcheting, the procedures described in ASME BPVC Section III division 5 are broad. They range from simple and conservative elastic methods to complicated and more realistic inelastic methodologies. More recently, Code Case N-861-1 was published, presenting a newly developed Elastic-Perfectly-Plastic analysis methodology to address the inapplicability of simplified methods for certain materials above temperatures where plasticity and creep behavior can not be decoupled.

This work aims to compare ratcheting results using elastic analysis, simplified-inelastic analysis, and Elastic-Perfectly-Plastic rules for a specific Class 1 nuclear component fabricated from SS316H operating at elevated temperatures for 100000 hours, testing different combinations of Primary and Secondary Stress combinations.

Presenting Author: Gaston Bourguigne Seaborg Technologies ApS

Presenting Author Biography: G. Bourguigne studied Mechanical Engineering in Mar del Plata, Argentina where he got his bachelor's degree. He for his Master's degree in Materials and Structures in France and then specialized in the Nuclear Energy Industry for more than 10 years.
Fatigue monitoring of operating nuclear power plants, seismic qualification, and plant life extension in both CANDU and german heavy water design plants.
He is now a Senior stress Analyst at Seaborg Technologies assisting in the design and verification of Class A and B high-temperature nuclear components.

Authors:

Gaston Bourguigne Seaborg Technologies ApS
Martin Brusconi Seaborg Technologies ApS