Session: CS-07-01 Recent Developments in ASME Codes and Standards-1

Paper Number: 122795

122795 - Substantiating the Design of a U-Tube Heat Exchanger's Tube-to-Tubesheet Joint: Demonstrating Conformance in Accordance With the Principles of Asme Bpvc Iii Class 1 Nuclear Components and Tema 

This paper presents the work conducted by Rolls-Royce to substantiate the design of a U-tube Heat Exchanger’s (HE) tube-to-tubesheet joint, including demonstrating conformance with the ASME Boiler and Pressure Vessel Code (BPVC) Section III NB rules for Class 1 nuclear components and the Standards of the Tubular Exchanger Manufacturers Association (TEMA).

The U-tube HE tubesheet forms part of the boundary between the shell-side and tube-side fluids. Tube-to-tubesheet joints locate the tubes within the tubesheet and consist of a hydraulically expanded region and a seal weld. Finite Element Analysis (FEA) could not accurately model the seal weld due to its small size causing singularities in the crevice region, generating unrealistic peak loads. Furthermore, local geometric constraints limited the use of a full-strength weld in lieu of a smaller seal weld.

Consequently, ASME BPVC Section III NB-3353, 4350 and 5274 were used in conjunction with the TEMA Class R and Class C rules to demonstrate safety and provide a robust design substantiation for the joint without FEA. Conformance to ASME BPVC Section III NB and compliance with the principles of TEMA Class R demonstrated that joint failure and subsequent fluid leakage will not occur.

This paper also describes the correlation between adhering to the rules of the ASME BPVC Section III NB and the TEMA standards and the mitigation of common failure mechanisms for tube-to-tubesheet joints. The risk of tube pull-out, fatigue, environmentally assisted cracking and weld failure were shown to be low when qualitatively assessed with knowledge of adherence to the ASME BPVC Section III NB code.

Presenting Author: William Shore Rolls-Royce plc

Presenting Author Biography: My name is William Shore and I am a Mechanical Design Engineer at Rolls-Royce in the United Kingdom. I hold an integrated Master's in Mechanical Engineering (MEng) Degree from Cardiff University.

I have a keen interest in pressure vessels and helping to advance pressure vessel technologies for the future. I also have experience in utilising the standards of ASME III NB for several pressure vessel applications.

Authors:

William Shore Rolls-Royce plc
Alexander Morris Rolls-Royce plc